API  4.2 For C++ developers
OpenSim::DeGrooteFregly2016Muscle Class Reference

This muscle model was published in De Groote et al. More...

Inheritance diagram for OpenSim::DeGrooteFregly2016Muscle:

## OpenSim Properties, Sockets, Outputs, Inputs

Properties (single-value)
double activation_time_constant
"Smaller value means activation can increase more rapidly. " "Default: 0.015 seconds." More...

double deactivation_time_constant
"Smaller value means activation can decrease more rapidly. " "Default: 0.060 seconds." More...

double default_activation
"Value of activation in the default state returned by " "initSystem(). Default: 0.5." More...

double default_normalized_tendon_force
"Value of normalized tendon force in the default state returned by " "initSystem(). Default: 0.5." More...

double active_force_width_scale
"Scale factor for the width of the active force-length curve. " "Larger values make the curve wider. Default: 1.0." More...

double fiber_damping
"Use this property to define the linear damping force that is " "added to the total muscle fiber force. It is computed by " "multiplying this damping parameter by the normalized fiber " "velocity and the max isometric force. Default: 0." More...

bool ignore_passive_fiber_force
"Make the passive fiber force 0. Default: false." More...

double passive_fiber_strain_at_one_norm_force
"Fiber strain when the passive fiber force is 1 normalized force. " "Default: 0.6." More...

double tendon_strain_at_one_norm_force
"Tendon strain at a tension of 1 normalized force. " "Default: 0.049." More...

std::string tendon_compliance_dynamics_mode
"The dynamics method used to enforce tendon compliance dynamics. " "Options: 'explicit' or 'implicit'. Default: 'explicit'. " More...

Outputs
double passive_fiber_elastic_force
Provides the value of getPassiveFiberElasticForce() and is available at stage SimTK::Stage::Dynamics . More...

double passive_fiber_elastic_force_along_tendon
Provides the value of getPassiveFiberElasticForceAlongTendon() and is available at stage SimTK::Stage::Dynamics . More...

double passive_fiber_damping_force
Provides the value of getPassiveFiberDampingForce() and is available at stage SimTK::Stage::Dynamics . More...

double passive_fiber_damping_force_along_tendon
Provides the value of getPassiveFiberDampingForceAlongTendon() and is available at stage SimTK::Stage::Dynamics . More...

double implicitresidual_normalized_tendon_force
Provides the value of getImplicitResidualNormalizedTendonForce() and is available at stage SimTK::Stage::Dynamics . More...

bool implicitenabled_normalized_tendon_force
Provides the value of getImplicitEnabledNormalizedTendonForce() and is available at stage SimTK::Stage::Model . More...

SimTK::Vec2 statebounds_normalized_tendon_force
Provides the value of getBoundsNormalizedTendonForce() and is available at stage SimTK::Stage::Model . More...

OpenSim Properties, Sockets, Outputs, Inputs inherited from OpenSim::Muscle
double max_isometric_force
"Maximum isometric force that the fibers can generate" More...

double optimal_fiber_length
"Optimal length of the muscle fibers" More...

double tendon_slack_length
"Resting length of the tendon" More...

double pennation_angle_at_optimal
"Angle between tendon and fibers at optimal fiber length expressed in radians" More...

double max_contraction_velocity
"Maximum contraction velocity of the fibers, in optimal fiberlengths/second" More...

bool ignore_tendon_compliance
"Compute muscle dynamics ignoring tendon compliance. Tendon is assumed to be rigid." More...

bool ignore_activation_dynamics
"Compute muscle dynamics ignoring activation dynamics. Activation is equivalent to excitation." More...

double excitation
Provides the value of getExcitation() and is available at stage SimTK::Stage::Dynamics . More...

double activation
Provides the value of getActivation() and is available at stage SimTK::Stage::Dynamics . More...

double fiber_length
Provides the value of getFiberLength() and is available at stage SimTK::Stage::Position . More...

double pennation_angle
Provides the value of getPennationAngle() and is available at stage SimTK::Stage::Position . More...

double cos_pennation_angle
Provides the value of getCosPennationAngle() and is available at stage SimTK::Stage::Position . More...

double tendon_length
Provides the value of getTendonLength() and is available at stage SimTK::Stage::Position . More...

double normalized_fiber_length
Provides the value of getNormalizedFiberLength() and is available at stage SimTK::Stage::Position . More...

double fiber_length_along_tendon
Provides the value of getFiberLengthAlongTendon() and is available at stage SimTK::Stage::Position . More...

double tendon_strain
Provides the value of getTendonStrain() and is available at stage SimTK::Stage::Position . More...

double passive_force_multiplier
Provides the value of getPassiveForceMultiplier() and is available at stage SimTK::Stage::Position . More...

double active_force_length_multiplier
Provides the value of getActiveForceLengthMultiplier() and is available at stage SimTK::Stage::Position . More...

double fiber_velocity
Provides the value of getFiberVelocity() and is available at stage SimTK::Stage::Velocity . More...

double normalized_fiber_velocity
Provides the value of getNormalizedFiberVelocity() and is available at stage SimTK::Stage::Velocity . More...

double fiber_velocity_along_tendon
Provides the value of getFiberVelocityAlongTendon() and is available at stage SimTK::Stage::Velocity . More...

double tendon_velocity
Provides the value of getTendonVelocity() and is available at stage SimTK::Stage::Velocity . More...

double force_velocity_multiplier
Provides the value of getForceVelocityMultiplier() and is available at stage SimTK::Stage::Velocity . More...

double pennation_angular_velocity
Provides the value of getPennationAngularVelocity() and is available at stage SimTK::Stage::Velocity . More...

double fiber_force
Provides the value of getFiberForce() and is available at stage SimTK::Stage::Dynamics . More...

double fiber_force_along_tendon
Provides the value of getFiberForceAlongTendon() and is available at stage SimTK::Stage::Dynamics . More...

double active_fiber_force
Provides the value of getActiveFiberForce() and is available at stage SimTK::Stage::Dynamics . More...

double passive_fiber_force
Provides the value of getPassiveFiberForce() and is available at stage SimTK::Stage::Dynamics . More...

double active_fiber_force_along_tendon
Provides the value of getActiveFiberForceAlongTendon() and is available at stage SimTK::Stage::Dynamics . More...

double passive_fiber_force_along_tendon
Provides the value of getPassiveFiberForceAlongTendon() and is available at stage SimTK::Stage::Dynamics . More...

double tendon_force
Provides the value of getTendonForce() and is available at stage SimTK::Stage::Dynamics . More...

double fiber_stiffness
Provides the value of getFiberStiffness() and is available at stage SimTK::Stage::Dynamics . More...

double fiber_stiffness_along_tendon
Provides the value of getFiberStiffnessAlongTendon() and is available at stage SimTK::Stage::Dynamics . More...

double tendon_stiffness
Provides the value of getTendonStiffness() and is available at stage SimTK::Stage::Dynamics . More...

double muscle_stiffness
Provides the value of getMuscleStiffness() and is available at stage SimTK::Stage::Dynamics . More...

double fiber_active_power
Provides the value of getFiberActivePower() and is available at stage SimTK::Stage::Dynamics . More...

double fiber_passive_power
Provides the value of getFiberPassivePower() and is available at stage SimTK::Stage::Dynamics . More...

double tendon_power
Provides the value of getTendonPower() and is available at stage SimTK::Stage::Dynamics . More...

double muscle_power
Provides the value of getMusclePower() and is available at stage SimTK::Stage::Dynamics . More...

OpenSim Properties, Sockets, Outputs, Inputs inherited from OpenSim::PathActuator
GeometryPath GeometryPath
"The set of points defining the path of the actuator." More...

double optimal_force
"The maximum force this actuator can produce." More...

double tension
Provides the value of computeActuation() and is available at stage SimTK::Stage::Acceleration . More...

OpenSim Properties, Sockets, Outputs, Inputs inherited from OpenSim::ScalarActuator
double min_control
"Minimum allowed value for control signal. Used primarily when solving " "for control values." More...

double max_control
"Maximum allowed value for control signal. Used primarily when solving " "for control values." More...

double actuation
Provides the value of getActuation() and is available at stage SimTK::Stage::Velocity . More...

double speed
Provides the value of getSpeed() and is available at stage SimTK::Stage::Velocity . More...

OpenSim Properties, Sockets, Outputs, Inputs inherited from OpenSim::Actuator
double power
Provides the value of getPower() and is available at stage SimTK::Stage::Dynamics . More...

OpenSim Properties, Sockets, Outputs, Inputs inherited from OpenSim::Force
bool appliesForce
"Flag indicating whether the force is applied or not. If true the force" "is applied to the MultibodySystem otherwise the force is not applied." "NOTE: Prior to OpenSim 4.0, this behavior was controlled by the " "'isDisabled' property, where 'true' meant that force was not being " "applied. Thus, if 'isDisabled' is true, then 'appliesForce is false." More...

double potential_energy
Provides the value of computePotentialEnergy() and is available at stage SimTK::Stage::Velocity . More...

OpenSim Properties, Sockets, Outputs, Inputs inherited from OpenSim::Component
Component components
"List of components that this component owns and serializes." More...

## Public Member Functions

DeGrooteFregly2016Muscle ()

Property-related functions
const double & get_activation_time_constant () const
Get the value of the activation_time_constant property. More...

double & upd_activation_time_constant ()
Get a writable reference to the activation_time_constant property. More...

void set_activation_time_constant (const double &value)
Set the value of the activation_time_constant property. More...

const double & get_deactivation_time_constant () const
Get the value of the deactivation_time_constant property. More...

double & upd_deactivation_time_constant ()
Get a writable reference to the deactivation_time_constant property. More...

void set_deactivation_time_constant (const double &value)
Set the value of the deactivation_time_constant property. More...

const double & get_default_activation () const
Get the value of the default_activation property. More...

double & upd_default_activation ()
Get a writable reference to the default_activation property. More...

void set_default_activation (const double &value)
Set the value of the default_activation property. More...

const double & get_default_normalized_tendon_force () const
Get the value of the default_normalized_tendon_force property. More...

double & upd_default_normalized_tendon_force ()
Get a writable reference to the default_normalized_tendon_force property. More...

void set_default_normalized_tendon_force (const double &value)
Set the value of the default_normalized_tendon_force property. More...

const double & get_active_force_width_scale () const
Get the value of the active_force_width_scale property. More...

double & upd_active_force_width_scale ()
Get a writable reference to the active_force_width_scale property. More...

void set_active_force_width_scale (const double &value)
Set the value of the active_force_width_scale property. More...

const double & get_fiber_damping () const
Get the value of the fiber_damping property. More...

double & upd_fiber_damping ()
Get a writable reference to the fiber_damping property. More...

void set_fiber_damping (const double &value)
Set the value of the fiber_damping property. More...

const bool & get_ignore_passive_fiber_force () const
Get the value of the ignore_passive_fiber_force property. More...

bool & upd_ignore_passive_fiber_force ()
Get a writable reference to the ignore_passive_fiber_force property. More...

void set_ignore_passive_fiber_force (const bool &value)
Set the value of the ignore_passive_fiber_force property. More...

const double & get_passive_fiber_strain_at_one_norm_force () const
Get the value of the passive_fiber_strain_at_one_norm_force property. More...

double & upd_passive_fiber_strain_at_one_norm_force ()
Get a writable reference to the passive_fiber_strain_at_one_norm_force property. More...

void set_passive_fiber_strain_at_one_norm_force (const double &value)
Set the value of the passive_fiber_strain_at_one_norm_force property. More...

const double & get_tendon_strain_at_one_norm_force () const
Get the value of the tendon_strain_at_one_norm_force property. More...

double & upd_tendon_strain_at_one_norm_force ()
Get a writable reference to the tendon_strain_at_one_norm_force property. More...

void set_tendon_strain_at_one_norm_force (const double &value)
Set the value of the tendon_strain_at_one_norm_force property. More...

const std::string & get_tendon_compliance_dynamics_mode () const
Get the value of the tendon_compliance_dynamics_mode property. More...

std::string & upd_tendon_compliance_dynamics_mode ()
Get a writable reference to the tendon_compliance_dynamics_mode property. More...

void set_tendon_compliance_dynamics_mode (const std::string &value)
Set the value of the tendon_compliance_dynamics_mode property. More...

Set methods.

If ignore_tendon_compliance is true, this sets nothing.

void setNormalizedTendonForce (SimTK::State &s, double normTendonForce) const

Public Member Functions inherited from OpenSim::Muscle
const double & get_max_isometric_force () const
Get the value of the max_isometric_force property. More...

double & upd_max_isometric_force ()
Get a writable reference to the max_isometric_force property. More...

void set_max_isometric_force (const double &value)
Set the value of the max_isometric_force property. More...

const double & get_optimal_fiber_length () const
Get the value of the optimal_fiber_length property. More...

double & upd_optimal_fiber_length ()
Get a writable reference to the optimal_fiber_length property. More...

void set_optimal_fiber_length (const double &value)
Set the value of the optimal_fiber_length property. More...

const double & get_tendon_slack_length () const
Get the value of the tendon_slack_length property. More...

double & upd_tendon_slack_length ()
Get a writable reference to the tendon_slack_length property. More...

void set_tendon_slack_length (const double &value)
Set the value of the tendon_slack_length property. More...

const double & get_pennation_angle_at_optimal () const
Get the value of the pennation_angle_at_optimal property. More...

double & upd_pennation_angle_at_optimal ()
Get a writable reference to the pennation_angle_at_optimal property. More...

void set_pennation_angle_at_optimal (const double &value)
Set the value of the pennation_angle_at_optimal property. More...

const double & get_max_contraction_velocity () const
Get the value of the max_contraction_velocity property. More...

double & upd_max_contraction_velocity ()
Get a writable reference to the max_contraction_velocity property. More...

void set_max_contraction_velocity (const double &value)
Set the value of the max_contraction_velocity property. More...

const bool & get_ignore_tendon_compliance () const
Get the value of the ignore_tendon_compliance property. More...

bool & upd_ignore_tendon_compliance ()
Get a writable reference to the ignore_tendon_compliance property. More...

void set_ignore_tendon_compliance (const bool &value)
Set the value of the ignore_tendon_compliance property. More...

const bool & get_ignore_activation_dynamics () const
Get the value of the ignore_activation_dynamics property. More...

bool & upd_ignore_activation_dynamics ()
Get a writable reference to the ignore_activation_dynamics property. More...

void set_ignore_activation_dynamics (const bool &value)
Set the value of the ignore_activation_dynamics property. More...

Muscle ()
Default constructor. More...

double getMaxIsometricForce () const
get/set the maximum isometric force (in N) that the fibers can generate More...

void setMaxIsometricForce (double maxIsometricForce)

double getOptimalFiberLength () const
get/set the optimal length (in m) of the muscle fibers (lumped as a single fiber) More...

void setOptimalFiberLength (double optimalFiberLength)

double getTendonSlackLength () const
get/set the resting (slack) length (in m) of the tendon that is in series with the muscle fiber More...

void setTendonSlackLength (double tendonSlackLength)

double getPennationAngleAtOptimalFiberLength () const
get/set the angle (in radians) between fibers at their optimal fiber length and the tendon More...

void setPennationAngleAtOptimalFiberLength (double pennationAngle)

double getMaxContractionVelocity () const
get/set the maximum contraction velocity of the fibers, in optimal fiber-lengths per second More...

void setMaxContractionVelocity (double maxContractionVelocity)

bool getIgnoreTendonCompliance (const SimTK::State &s) const
Get/set Modeling (runtime) option to ignore tendon compliance when computing muscle dynamics. More...

void setIgnoreTendonCompliance (SimTK::State &s, bool ignore) const

bool getIgnoreActivationDynamics (const SimTK::State &s) const
Get/set Modeling (runtime) option to ignore activation dynamics when computing muscle dynamics. More...

void setIgnoreActivationDynamics (SimTK::State &s, bool ignore) const

double getFiberLength (const SimTK::State &s) const
get the current working fiber length (m) for the muscle More...

double getPennationAngle (const SimTK::State &s) const
get the current pennation angle (radians) between the fiber and tendon at the current fiber length More...

double getCosPennationAngle (const SimTK::State &s) const
get the cosine of the current pennation angle (radians) between the fiber and tendon at the current fiber length More...

double getTendonLength (const SimTK::State &s) const
get the current tendon length (m) given the current joint angles and fiber length More...

double getNormalizedFiberLength (const SimTK::State &s) const
get the current normalized fiber length (fiber_length/optimal_fiber_length) More...

double getFiberLengthAlongTendon (const SimTK::State &s) const
get the current fiber length (m) projected (*cos(pennationAngle)) onto the tendon direction More...

double getTendonStrain (const SimTK::State &s) const
get the current tendon strain (delta_l/tendon_slack_length is dimensionless) More...

double getFiberPotentialEnergy (const SimTK::State &s) const
the potential energy (J) stored in the fiber due to its parallel elastic element More...

double getTendonPotentialEnergy (const SimTK::State &s) const
the potential energy (J) stored in the tendon More...

double getMusclePotentialEnergy (const SimTK::State &s) const
the total potential energy (J) stored in the muscle More...

double getPassiveForceMultiplier (const SimTK::State &s) const
get the passive fiber (parallel elastic element) force multiplier More...

double getActiveForceLengthMultiplier (const SimTK::State &s) const
get the active fiber (contractile element) force multiplier due to current fiber length More...

double getFiberVelocity (const SimTK::State &s) const
get current fiber velocity (m/s) positive is lengthening More...

double getNormalizedFiberVelocity (const SimTK::State &s) const
get normalized fiber velocity. More...

double getFiberVelocityAlongTendon (const SimTK::State &s) const
get the current fiber velocity (m/s) projected onto the tendon direction More...

double getPennationAngularVelocity (const SimTK::State &s) const
get pennation angular velocity (radians/s) More...

double getTendonVelocity (const SimTK::State &s) const
get the tendon velocity (m/s) positive is lengthening More...

double getForceVelocityMultiplier (const SimTK::State &s) const
get the dimensionless multiplier resulting from the fiber's force-velocity curve More...

double getFiberForce (const SimTK::State &s) const
get the current fiber force (N) applied to the tendon More...

double getFiberForceAlongTendon (const SimTK::State &s) const
get the force of the fiber (N/m) along the direction of the tendon More...

double getActiveFiberForce (const SimTK::State &s) const
get the current active fiber force (N) due to activation*force_length*force_velocity relationships More...

double getPassiveFiberForce (const SimTK::State &s) const
get the total force applied by all passive elements in the fiber (N) More...

double getActiveFiberForceAlongTendon (const SimTK::State &s) const
get the current active fiber force (N) projected onto the tendon direction More...

double getPassiveFiberForceAlongTendon (const SimTK::State &s) const
get the total force applied by all passive elements in the fiber (N) projected onto the tendon direction More...

double getTendonForce (const SimTK::State &s) const
get the current tendon force (N) applied to bones More...

double getFiberStiffness (const SimTK::State &s) const
get the current fiber stiffness (N/m) defined as the partial derivative of fiber force with respect to fiber length More...

double getFiberStiffnessAlongTendon (const SimTK::State &s) const
get the stiffness of the fiber (N/m) along the direction of the tendon, that is the partial derivative of the fiber force along the tendon with respect to small changes in fiber length along the tendon More...

double getTendonStiffness (const SimTK::State &s) const
get the current tendon stiffness (N/m) defined as the partial derivative of tendon force with respect to tendon length More...

double getMuscleStiffness (const SimTK::State &s) const
get the current muscle stiffness (N/m) defined as the partial derivative of muscle force with respect to muscle length More...

double getFiberActivePower (const SimTK::State &s) const
get the current active fiber power (W) More...

double getFiberPassivePower (const SimTK::State &s) const
get the current passive fiber power (W) More...

double getTendonPower (const SimTK::State &s) const
get the current tendon power (W) More...

double getMusclePower (const SimTK::State &s) const
get the current muscle power (W) More...

double getStress (const SimTK::State &s) const override
get the stress in the muscle (part of the Actuator interface as well) More...

void setExcitation (SimTK::State &s, double excitation) const
set the excitation (control) for this muscle. More...

double getExcitation (const SimTK::State &s) const

void computeEquilibrium (SimTK::State &s) const override final
Find and set the equilibrium state of the muscle (if any) More...

void assign (Object &aObject) override
This allows copy assignment in the Java GUI. More...

Public Member Functions inherited from OpenSim::PathActuator
PathActuator ()

GeometryPathupdGeometryPath ()

const GeometryPathgetGeometryPath () const

bool hasGeometryPath () const override
Return a flag indicating whether the Force is applied along a Path. More...

void setOptimalForce (double aOptimalForce)

double getOptimalForce () const override

virtual double getLength (const SimTK::State &s) const

virtual double getLengtheningSpeed (const SimTK::State &s) const

double getPower (const SimTK::State &s) const override

double getStress (const SimTK::State &s) const override

void addNewPathPoint (const std::string &proposedName, const PhysicalFrame &aBody, const SimTK::Vec3 &aPositionOnBody)
Note that this function does not maintain the State and so should be used only before a valid State is created. More...

double computeActuation (const SimTK::State &s) const override

virtual double computeMomentArm (const SimTK::State &s, Coordinate &aCoord) const

const GeometryPathget_GeometryPath () const
Get the value of the GeometryPath property. More...

GeometryPathupd_GeometryPath ()
Get a writable reference to the GeometryPath property. More...

void set_GeometryPath (const GeometryPath &value)
Set the value of the GeometryPath property. More...

const double & get_optimal_force () const
Get the value of the optimal_force property. More...

double & upd_optimal_force ()
Get a writable reference to the optimal_force property. More...

void set_optimal_force (const double &value)
Set the value of the optimal_force property. More...

void assign (Object &aObject) override
This allows copy assignment in the Java GUI. More...

PathActuatorclone () const override
Create a new heap-allocated copy of the concrete object to which this Object refers. More...

const std::string & getConcreteClassName () const override
Returns the class name of the concrete Object-derived class of the actual object referenced by this Object, as a string. More...

Public Member Functions inherited from OpenSim::ScalarActuator
ScalarActuator ()

virtual double getControl (const SimTK::State &s) const
Convenience method to get control given scalar (double) valued control. More...

int numControls () const override

virtual void setActuation (const SimTK::State &s, double aActuation) const

virtual double getActuation (const SimTK::State &s) const

virtual void setSpeed (const SimTK::State &s, double aspeed) const

virtual double getSpeed (const SimTK::State &s) const

void setMinControl (const double &aMinControl)
Methods to manage the bounds on ScalarActuator's control. More...

double getMinControl () const

void setMaxControl (const double &aMaxControl)

double getMaxControl () const

void overrideActuation (SimTK::State &s, bool flag) const
Enable/disable a ScalarActuator's override actuation. More...

bool isActuationOverridden (const SimTK::State &s) const
return ScalarActuator's override status More...

void setOverrideActuation (SimTK::State &s, double value) const
set the actuation value used when the override is true More...

double getOverrideActuation (const SimTK::State &s) const
return override actuation More...

const double & get_min_control () const
Get the value of the min_control property. More...

double & upd_min_control ()
Get a writable reference to the min_control property. More...

void set_min_control (const double &value)
Set the value of the min_control property. More...

const double & get_max_control () const
Get the value of the max_control property. More...

double & upd_max_control ()
Get a writable reference to the max_control property. More...

void set_max_control (const double &value)
Set the value of the max_control property. More...

void assign (Object &aObject) override
This allows copy assignment in the Java GUI. More...

Public Member Functions inherited from OpenSim::Actuator
Actuator ()

virtual const SimTK::Vector getDefaultControls ()
Actuator default controls are zero. More...

virtual const SimTK::VectorView_< double > getControls (const SimTK::State &s) const

virtual void getControls (const SimTK::Vector &modelControls, SimTK::Vector &actuatorControls) const
Convenience methods for getting, setting and adding to actuator controls from/into the model controls. More...

virtual void setControls (const SimTK::Vector &actuatorControls, SimTK::Vector &modelControls) const
set actuator controls subvector into the right slot in the system-wide model controls More...

virtual void addInControls (const SimTK::Vector &actuatorControls, SimTK::Vector &modelControls) const
add actuator controls to the values already occupying the slot in the system-wide model controls More...

void assign (Object &aObject) override
This allows copy assignment in the Java GUI. More...

Public Member Functions inherited from OpenSim::Force
virtual bool shouldBeParallelized () const
Tell SimBody to parallelize this force. More...

bool appliesForce (const SimTK::State &s) const
Return if the Force is applied (or enabled) or not. More...

void setAppliesForce (SimTK::State &s, bool applyForce) const
Set whether or not the Force is applied. More...

const bool & get_appliesForce () const
Get the value of the appliesForce property. More...

bool & upd_appliesForce ()
Get a writable reference to the appliesForce property. More...

void set_appliesForce (const bool &value)
Set the value of the appliesForce property. More...

void assign (Object &aObject) override
This allows copy assignment in the Java GUI. More...

Public Member Functions inherited from OpenSim::ModelComponent
ModelComponent ()
Default constructor. More...

ModelComponent (const std::string &aFileName, bool aUpdateFromXMLNode=true)
Construct ModelComponent from an XML file. More...

ModelComponent (SimTK::Xml::Element &aNode)
Construct ModelComponent from a specific node in an XML document. More...

virtual ~ModelComponent ()
Destructor is virtual to allow concrete model component cleanup. More...

void connectToModel (Model &model)
Connect this ModelComponent to its aggregate- a Model. More...

const ModelgetModel () const
Get a const reference to the Model this component is part of. More...

ModelupdModel ()
Get a modifiable reference to the Model this component is part of. More...

bool hasModel () const
Does this ModelComponent have a Model associated with it? More...

void preScale (const SimTK::State &s, const ScaleSet &scaleSet)
Perform any computations that must occur before ModelComponent::scale() is invoked on all ModelComponents in the Model. More...

void scale (const SimTK::State &s, const ScaleSet &scaleSet)
Scale the ModelComponent. More...

void postScale (const SimTK::State &s, const ScaleSet &scaleSet)
Perform any computations that must occur after ModelComponent::scale() has been invoked on all ModelComponents in the Model. More...

void assign (Object &aObject) override
This allows copy assignment in the Java GUI. More...

Public Member Functions inherited from OpenSim::Component
Component ()
Default constructor. More...

Component (const std::string &aFileName, bool aUpdateFromXMLNode=true)
Construct Component from an XML file. More...

Component (SimTK::Xml::Element &aNode)
Construct Component from a specific node in an XML document. More...

Component (const Component &)=default
Use default copy constructor and assignment operator. More...

Componentoperator= (const Component &)=default

virtual ~Component ()=default
Destructor is virtual to allow concrete Component to cleanup. More...

virtual void generateDecorations (bool fixed, const ModelDisplayHints &hints, const SimTK::State &state, SimTK::Array_< SimTK::DecorativeGeometry > &appendToThis) const
Optional method for generating arbitrary display geometry that reflects this Component at the specified state. More...

const SimTK::MultibodySystem & getSystem () const
Get the underlying MultibodySystem that this component is connected to. More...

bool hasSystem () const
Check if this component has an underlying MultibodySystem. More...

bool isComponentInOwnershipTree (const Component *component) const
Does the provided component already exist anywhere in the ownership tree (not just subcomponents of this component)? More...

Add a Component (as a subcomponent) of this component. More...

template<typename T = Component>
ComponentList< const T > getComponentList () const
Get an iterator through the underlying subcomponents that this component is composed of. More...

template<typename T = Component>
ComponentList< T > updComponentList ()
Similar to getComponentList(), except the resulting list allows one to modify the components. More...

template<typename T = Component>
unsigned countNumComponents () const
Uses getComponentList<T>() to count the number of underlying subcomponents of the specified type. More...

std::string getAbsolutePathString () const
Get the complete (absolute) pathname for this Component to its ancestral Component, which is the root of the tree to which this Component belongs. More...

ComponentPath getAbsolutePath () const
Return a ComponentPath of the absolute path of this Component. More...

std::string getRelativePathString (const Component &wrt) const
Get the relative path of this Component with respect to another Component, as a string. More...

ComponentPath getRelativePath (const Component &wrt) const
Get the relative path of this Component with respect to another Component. More...

bool hasComponent (const std::string &pathname) const
Query if there is a component (of any type) at the specified path name. More...

template<class C = Component>
bool hasComponent (const std::string &pathname) const
Query if there is a component of a given type at the specified path name. More...

template<class C = Component>
const C & getComponent (const std::string &pathname) const
Get a unique subcomponent of this Component by its path name and type 'C'. More...

template<class C = Component>
const C & getComponent (const ComponentPath &pathname) const

const ComponentgetComponent (const std::string &pathname) const
Similar to the templatized getComponent(), except this returns the component as the generic Component type. More...

template<class C = Component>
C & updComponent (const std::string &name)
Get a writable reference to a subcomponent. More...

template<class C = Component>
C & updComponent (const ComponentPath &name)

ComponentupdComponent (const std::string &pathname)
Similar to the templatized updComponent(), except this returns the component as the generic Component type. More...

unsigned printComponentsMatching (const std::string &substring) const
Print a list to the console of all components whose absolute path name contains the given string. More...

int getNumStateVariables () const
Get the number of "continuous" state variables maintained by the Component and its subcomponents. More...

Array< std::string > getStateVariableNames () const
Get the names of "continuous" state variables maintained by the Component and its subcomponents. More...

template<class C = Component>
const C * findComponent (const ComponentPath &pathToFind) const
Find a Component to which this Component is an ancestor—in other words, a Component that is directly owned by this Component or is owned by one of its sub-components, sub-sub-components, etc. More...

template<class C = Component>
const C * findComponent (const std::string &pathToFind) const
Same as findComponent(const ComponentPath&), but accepting a string (a path or just a name) as input. More...

const StateVariabletraverseToStateVariable (const std::string &pathName) const
Get a StateVariable anywhere in the Component tree, given a StateVariable path. More...

void finalizeFromProperties ()
Define a Component's internal data members and structure according to its properties. More...

void finalizeConnections (Component &root)
Satisfy the Component's connections specified by its Sockets and Inputs. More...

void clearConnections ()
Disconnect/clear this Component from its aggregate component. More...

Have the Component add itself to the underlying computational System. More...

void initStateFromProperties (SimTK::State &state) const
Initialize Component's state variable values from its properties. More...

void setPropertiesFromState (const SimTK::State &state)
Set Component's properties given a state. More...

int getNumSockets () const
Get the number of Sockets in this Component. More...

std::vector< std::string > getSocketNames ()
Collect and return the names of the sockets in this component. More...

template<typename T >
const T & getConnectee (const std::string &name) const
Get the "connectee" object that the Component's Socket is bound to. More...

const ObjectgetConnectee (const std::string &name) const
Get the connectee as an Object. More...

const AbstractSocketgetSocket (const std::string &name) const
Get an AbstractSocket for the given socket name. More...

AbstractSocketupdSocket (const std::string &name)
Get a writable reference to the AbstractSocket for the given socket name. More...

template<typename T >
const Socket< T > & getSocket (const std::string &name) const
Get a const reference to the concrete Socket provided by this Component by name. More...

template<typename T >
Socket< T > & updSocket (const std::string &name)
Get a writable reference to the concrete Socket provided by this Component by name. More...

void printSubcomponentInfo () const
List all subcomponents by name and recurse into these components to list their subcomponents, and so on. More...

void printSocketInfo () const
List all the Sockets of this component and whether or not they are connected. More...

void printInputInfo () const
List all the inputs of this component and whether or not they are connected. More...

template<typename C >
void printSubcomponentInfo () const

void printOutputInfo (const bool includeDescendants=true) const
Print outputs of this component and optionally, those of all subcomponents. More...

void assign (Object &aObject) override
This allows copy assignment in the Java GUI. More...

int getNumInputs () const
Access the number of Inputs that this component has. More...

int getNumOutputs () const
Access the number of Outputs that this component has. More...

std::vector< std::string > getInputNames () const
Collect and return the names of Inputs in this component as an std::vector. More...

std::vector< std::string > getOutputNames () const
Collect and return the names of Outputs in this component as an std::vector. More...

const AbstractInputgetInput (const std::string &name) const
Get an Input provided by this Component by name. More...

AbstractInputupdInput (const std::string &name)
Get a writable reference to an Input provided by this Component by name. More...

template<typename T >
const Input< T > & getInput (const std::string &name) const
Get a concrete Input that you can directly ask for its values. More...

const AbstractOutputgetOutput (const std::string &name) const
Get the Output provided by this Component by name. More...

AbstractOutputupdOutput (const std::string &name)
Get a writable reference to an Output provided by this Component by name. More...

SimTK::IteratorRange< OutputConstIteratorgetOutputs () const
Iterate through all Outputs of this component. More...

int getModelingOption (const SimTK::State &state, const std::string &name) const
Get a ModelingOption flag for this Component by name. More...

void setModelingOption (SimTK::State &state, const std::string &name, int flag) const
Set the value of a ModelingOption flag for this Component. More...

template<typename T >
const T & getInputValue (const SimTK::State &state, const std::string &name) const
Get the Input value that this component is dependent on. More...

template<typename T >
const T & getOutputValue (const SimTK::State &state, const std::string &name) const
Get the Output value provided by this Component by name. More...

double getStateVariableValue (const SimTK::State &state, const std::string &name) const
Get the value of a state variable allocated by this Component. More...

void setStateVariableValue (SimTK::State &state, const std::string &name, double value) const
Set the value of a state variable allocated by this Component by name. More...

SimTK::Vector getStateVariableValues (const SimTK::State &state) const
Get all values of the state variables allocated by this Component. More...

void setStateVariableValues (SimTK::State &state, const SimTK::Vector &values) const
Set all values of the state variables allocated by this Component. More...

double getStateVariableDerivativeValue (const SimTK::State &state, const std::string &name) const
Get the value of a state variable derivative computed by this Component. More...

double getDiscreteVariableValue (const SimTK::State &state, const std::string &name) const
Get the value of a discrete variable allocated by this Component by name. More...

void setDiscreteVariableValue (SimTK::State &state, const std::string &name, double value) const
Set the value of a discrete variable allocated by this Component by name. More...

template<class T >
SimTK::CacheEntryIndex getCacheVariableIndex (const CacheVariable< T > &cv) const
Get the index of a Component's cache variable in the Subsystem for allocations. More...

SimTK::CacheEntryIndex getCacheVariableIndex (const std::string &name) const
Get the index of a Component's cache variable in the Subsystem for allocations. More...

template<class T >
const T & getCacheVariableValue (const SimTK::State &state, const std::string &name) const
Get the value of a cache variable allocated by this Component by name. More...

template<class T >
const T & getCacheVariableValue (const SimTK::State &state, const CacheVariable< T > &cv) const
Get the value of a cache variable allocated by this Component. More...

template<typename T >
void setCacheVariableValue (const SimTK::State &state, const std::string &k, T value) const
Set the value of a cache variable, identified by name, to a new value and mark the cache variable as valid. More...

template<typename T >
void setCacheVariableValue (const SimTK::State &state, const CacheVariable< T > &cv, T value) const
Set the value of a cache variable to a new value and mark the cache variable as valid. More...

template<typename T >
T & updCacheVariableValue (const SimTK::State &state, const std::string &name) const
Returns a mutable reference to the value of a cache variable identified by name. More...

template<typename T >
T & updCacheVariableValue (const SimTK::State &state, const CacheVariable< T > &cv) const
Returns a mutable reference to the value of a cache variable. More...

bool isCacheVariableValid (const SimTK::State &state, const std::string &name) const
Returns true if the cache variable, identified by name, is valid. More...

template<class T >
bool isCacheVariableValid (const SimTK::State &state, const CacheVariable< T > &cv) const
Returns true if the cache variable is valid. More...

void markCacheVariableValid (const SimTK::State &state, const std::string &name) const
Marks the value of a cache variable, identified by name, as valid. More...

template<typename T >
void markCacheVariableValid (const SimTK::State &state, const CacheVariable< T > &cv) const
Marks the value of a cache variable as valid. More...

void markCacheVariableInvalid (const SimTK::State &state, const std::string &name) const
Marks the value of a cache variable, identified by name, as invalid. More...

template<class T >
void markCacheVariableInvalid (const SimTK::State &state, const CacheVariable< T > &cv) const
Marks the value of a cache variable as invalid. More...

const ComponentgetOwner () const
Access the owner of this Component. More...

bool hasOwner () const
(For advanced users) Check if this Component has an owner. More...

const ComponentgetRoot () const
Obtain the root Component, which is this component if it is orphaned. More...

Public Member Functions inherited from OpenSim::Object
virtual ~Object ()
Virtual destructor for cleanup. More...

bool isEqualTo (const Object &aObject) const
Equality operator wrapper for use from languages not supporting operator overloading. More...

Objectoperator= (const Object &aObject)
Copy assignment copies he base class fields, including the properties. More...

virtual bool operator== (const Object &aObject) const
Determine if two objects are equal. More...

virtual bool operator< (const Object &aObject) const
Provide an ordering for objects so they can be put in sorted containers. More...

void setName (const std::string &name)
Set the name of the Object. More...

const std::string & getName () const
Get the name of this Object. More...

void setDescription (const std::string &description)
Set description, a one-liner summary. More...

const std::string & getDescription () const
Get description, a one-liner summary. More...

const std::string & getAuthors () const
Get Authors of this Object. More...

void setAuthors (const std::string &authors)
Set Authors of this object. More...

const std::string & getReferences () const
Get references or publications to cite if using this object. More...

void setReferences (const std::string &references)
Set references or publications to cite if using this object. More...

int getNumProperties () const
Determine how many properties are stored with this Object. More...

const AbstractPropertygetPropertyByIndex (int propertyIndex) const
Get a const reference to a property by its index number, returned as an AbstractProperty. More...

AbstractPropertyupdPropertyByIndex (int propertyIndex)
Get a writable reference to a property by its index number, returned as an AbstractProperty. More...

bool hasProperty (const std::string &name) const
Return true if this Object has a property of any type with the given name, which must not be empty. More...

const AbstractPropertygetPropertyByName (const std::string &name) const
Get a const reference to a property by its name, returned as an AbstractProperty. More...

AbstractPropertyupdPropertyByName (const std::string &name)
Get a writable reference to a property by its name, returned as an AbstractProperty. More...

template<class T >
bool hasProperty () const
Return true if this Object contains an unnamed, one-object property that contains objects of the given template type T. More...

template<class T >
const Property< T > & getProperty (const PropertyIndex &index) const
Get property of known type Property<T> as a const reference; the property must be present and have the right type. More...

template<class T >
Property< T > & updProperty (const PropertyIndex &index)
Get property of known type Property<T> as a writable reference; the property must be present and have the right type. More...

bool isObjectUpToDateWithProperties () const
Returns true if no property's value has changed since the last time setObjectIsUpToDateWithProperties() was called. More...

void readObjectFromXMLNodeOrFile (SimTK::Xml::Element &objectElement, int versionNumber)
We're given an XML element from which we are to populate this Object. More...

void updateXMLNode (SimTK::Xml::Element &parent, const AbstractProperty *prop=nullptr) const
Serialize this object into the XML node that represents it. More...

bool getInlined () const
Inlined means an in-memory Object that is not associated with an XMLDocument. More...

void setInlined (bool aInlined, const std::string &aFileName="")
Mark this as inlined or not and optionally provide a file name to associate with the new XMLDocument for the non-inline case. More...

std::string getDocumentFileName () const
If there is a document associated with this object then return the file name maintained by the document. More...

int getDocumentFileVersion () const
If there is a document associated with this object then return its version number. More...

void setAllPropertiesUseDefault (bool aUseDefault)

bool print (const std::string &fileName) const
Write this Object into an XML file of the given name; conventionally the suffix to use is ".osim". More...

std::string dump () const
dump the XML representation of this Object into an std::string and return it. More...

virtual bool isA (const char *type) const
The default implementation returns true only if the supplied string is "Object"; each Object-derived class overrides this to match its own class name. More...

const std::string & toString () const
Wrapper to be used on Java side to display objects in tree; this returns just the object's name. More...

PropertySetgetPropertySet ()
OBSOLETE: Get a reference to the PropertySet maintained by the Object. More...

const PropertySetgetPropertySet () const

## Public Types

typedef DeGrooteFregly2016Muscle Self
This typedef might be useful within the member functions of this class. More...

typedef Muscle Super
Use this typedef to refer to the superclass of this class. More...

Public Types inherited from OpenSim::Muscle
typedef Muscle Self
This typedef might be useful within the member functions of this class. More...

typedef PathActuator Super
Use this typedef to refer to the superclass of this class. More...

Public Types inherited from OpenSim::PathActuator
typedef PathActuator Self
This typedef might be useful within the member functions of this class. More...

typedef ScalarActuator Super
Use this typedef to refer to the superclass of this class. More...

Public Types inherited from OpenSim::ScalarActuator
typedef ScalarActuator Self
This typedef might be useful within the member functions of this class. More...

typedef Actuator Super
Use this typedef to refer to the superclass of this class. More...

Public Types inherited from OpenSim::Actuator
typedef Actuator Self
This typedef might be useful within the member functions of this class. More...

typedef Force Super
Use this typedef to refer to the superclass of this class. More...

Public Types inherited from OpenSim::Force
typedef Force Self
This typedef might be useful within the member functions of this class. More...

typedef ModelComponent Super
Use this typedef to refer to the superclass of this class. More...

Public Types inherited from OpenSim::ModelComponent
typedef ModelComponent Self
This typedef might be useful within the member functions of this class. More...

typedef Component Super
Use this typedef to refer to the superclass of this class. More...

Public Types inherited from OpenSim::Component
typedef Component Self
This typedef might be useful within the member functions of this class. More...

typedef Object Super
Use this typedef to refer to the superclass of this class. More...

typedef std::map< std::string, SimTK::ClonePtr< AbstractOutput > >::const_iterator OutputConstIterator
Define OutputConstIterator for convenience. More...

## Protected Member Functions

Component interface
void extendFinalizeFromProperties () override
Perform any time-invariant calculations, data structure initializations, or other configuration based on the component's properties to form a functioning (but not yet connected) component. More...

void extendAddToSystem (SimTK::MultibodySystem &system) const override
Add appropriate Simbody elements (if needed) to the System corresponding to this component and specify needed state resources. More...

void extendInitStateFromProperties (SimTK::State &s) const override
Transfer property values or other state-independent initial values into this component's state variables in the passed-in state argument. More...

void extendSetPropertiesFromState (const SimTK::State &s) override
Update this component's property values to match the specified State, if the component has created any state variable that is intended to correspond to a property. More...

void computeStateVariableDerivatives (const SimTK::State &s) const override
If a model component has allocated any continuous state variables using the addStateVariable() method, then computeStateVariableDerivatives() must be implemented to provide time derivatives for those states. More...

Actuator interface
double computeActuation (const SimTK::State &s) const override
Actuator interface for a muscle computes the tension in the muscle and applied by the tendon to bones (i.e. More...

Protected Member Functions inherited from OpenSim::Muscle
const MuscleLengthInfogetMuscleLengthInfo (const SimTK::State &s) const

MuscleLengthInfoupdMuscleLengthInfo (const SimTK::State &s) const

const FiberVelocityInfogetFiberVelocityInfo (const SimTK::State &s) const

FiberVelocityInfoupdFiberVelocityInfo (const SimTK::State &s) const

const MuscleDynamicsInfogetMuscleDynamicsInfo (const SimTK::State &s) const

MuscleDynamicsInfoupdMuscleDynamicsInfo (const SimTK::State &s) const

const MusclePotentialEnergyInfogetMusclePotentialEnergyInfo (const SimTK::State &s) const

MusclePotentialEnergyInfoupdMusclePotentialEnergyInfo (const SimTK::State &s) const

void computeForce (const SimTK::State &state, SimTK::Vector_< SimTK::SpatialVec > &bodyForces, SimTK::Vector &generalizedForce) const override
Force interface applies tension to bodies, and Muscle also checks that applied muscle tension is not negative. More...

double computePotentialEnergy (const SimTK::State &state) const override
Potential energy stored by the muscle. More...

SimTK::Vec3 computePathColor (const SimTK::State &state) const override
Override PathActuator virtual to calculate a preferred color for the muscle path based on activation. More...

void extendConnectToModel (Model &aModel) override
Model Component creation interface. More...

void extendAddToSystem (SimTK::MultibodySystem &system) const override
Add appropriate Simbody elements (if needed) to the System corresponding to this component and specify needed state resources. More...

void extendSetPropertiesFromState (const SimTK::State &s) override
Subclass should override; be sure to invoke Force::extendSetPropertiesFromState() at the beginning of the overriding method. More...

void extendInitStateFromProperties (SimTK::State &state) const override
Subclass should override; be sure to invoke Super::extendInitStateFromProperties() at the beginning of the overriding method. More...

virtual void updateGeometry (const SimTK::State &s)

Protected Member Functions inherited from OpenSim::PathActuator
void extendRealizeDynamics (const SimTK::State &state) const override
Extension of parent class method; derived classes may extend further. More...

Protected Member Functions inherited from OpenSim::ScalarActuator
double computeOverrideActuation (const SimTK::State &s) const

OpenSim::Array< std::string > getRecordLabels () const override
Methods to query a actuation for the value actually applied during simulation. More...

OpenSim::Array< double > getRecordValues (const SimTK::State &state) const override
Given SimTK::State object extract all the values necessary to report actuation, application location frame, etc. More...

Protected Member Functions inherited from OpenSim::Force
Force ()
Default constructor sets up Force-level properties; can only be called from a derived class constructor. More...

Force (SimTK::Xml::Element &node)
Deserialization from XML, necessary so that derived classes can (de)serialize. More...

void applyForceToPoint (const SimTK::State &state, const PhysicalFrame &body, const SimTK::Vec3 &point, const SimTK::Vec3 &force, SimTK::Vector_< SimTK::SpatialVec > &bodyForces) const
Apply a force at a particular point (a "station") on a given body. More...

void applyTorque (const SimTK::State &state, const PhysicalFrame &body, const SimTK::Vec3 &torque, SimTK::Vector_< SimTK::SpatialVec > &bodyForces) const
Apply a torque to a particular body. More...

void applyGeneralizedForce (const SimTK::State &state, const Coordinate &coord, double force, SimTK::Vector &generalizedForces) const
Apply a generalized force. More...

Protected Member Functions inherited from OpenSim::ModelComponent
const SimTK::Vec3 & getScaleFactors (const ScaleSet &scaleSet, const Frame &frame) const
Get the scale factors corresponding to the base OpenSim::Body of the specified Frame. More...

virtual void extendPreScale (const SimTK::State &s, const ScaleSet &scaleSet)
Perform any computations that must occur before ModelComponent::scale() is invoked on all ModelComponents in the Model. More...

virtual void extendScale (const SimTK::State &s, const ScaleSet &scaleSet)
Scale the ModelComponent. More...

virtual void extendPostScale (const SimTK::State &s, const ScaleSet &scaleSet)
Perform any computations that must occur after ModelComponent::scale() has been invoked on all ModelComponents in the Model. More...

void extendFinalizeFromProperties () override
Perform any time-invariant calculations, data structure initializations, or other configuration based on the component's properties to form a functioning (but not yet connected) component. More...

Protected Member Functions inherited from OpenSim::Component
SimTK_DEFINE_UNIQUE_INDEX_TYPE (MemberSubcomponentIndex)

template<class C = Component>
MemberSubcomponentIndex constructSubcomponent (const std::string &name)
Construct a subcomponent as a data member of this Component. More...

template<class C = Component>
const C & getMemberSubcomponent (MemberSubcomponentIndex ix) const

template<class C = Component>
C & updMemberSubcomponent (MemberSubcomponentIndex ix)

Adopt a component as a subcomponent of this Component. More...

size_t getNumImmediateSubcomponents () const
Get the number of Subcomponents immediately owned by this Component. More...

size_t getNumMemberSubcomponents () const
Get the number of Subcomponents that are data members of this Component. More...

size_t getNumPropertySubcomponents () const
Get the number of Subcomponents that are properties of this Component. More...

Get the number of Subcomponents adopted by this Component. More...

std::vector< SimTK::ReferencePtr< const Component > > getImmediateSubcomponents () const
Access this Component's immediate subcomponents (not those owned by subcomponents) More...

template<class C >
const C * traversePathToComponent (ComponentPath path) const

void setNextSubcomponentInSystem (const Component &sub) const
Helper method to enable Component makers to specify the order of their subcomponents to be added to the System during addToSystem(). More...

void resetSubcomponentOrder ()
resetSubcomponentOrder clears this Component's list of ordered subcomponents (but otherwise leaves subcomponents untouched). More...

const Componentget_components (int i) const
Get the value of the i-th element of the components property. More...

Componentupd_components (int i)
Get a writable reference to the i-th element of the components property. More...

void set_components (int i, const Component &value)
Set the value of the i-th element of components property. More...

int append_components (const Component &value)
Append an element to the components property. More...

Perform any secondary operations, e.g. More...

void initComponentTreeTraversal (const Component &root) const
Build the tree of Components from this component through its descendants. More...

virtual void extendAddToSystemAfterSubcomponents (SimTK::MultibodySystem &system) const
Add appropriate Simbody elements (if needed) to the System after your component's subcomponents have had a chance to add themselves to the system. More...

void setStateVariableDerivativeValue (const SimTK::State &state, const std::string &name, double deriv) const
Set the derivative of a state variable by name when computed inside of this Component's computeStateVariableDerivatives() method. More...

virtual void extendRealizeTopology (SimTK::State &state) const
Obtain state resources that are needed unconditionally, and perform computations that depend only on the system topology. More...

virtual void extendRealizeModel (SimTK::State &state) const
Obtain and name state resources (like state variables allocated by an underlying Simbody component) that may be needed, depending on modeling options. More...

virtual void extendRealizeInstance (const SimTK::State &state) const
Perform computations that depend only on instance variables, like lengths and masses. More...

virtual void extendRealizeTime (const SimTK::State &state) const
Perform computations that depend only on time and earlier stages. More...

virtual void extendRealizePosition (const SimTK::State &state) const
Perform computations that depend only on position-level state variables and computations performed in earlier stages (including time). More...

virtual void extendRealizeVelocity (const SimTK::State &state) const
Perform computations that depend only on velocity-level state variables and computations performed in earlier stages (including position, and time). More...

virtual void extendRealizeAcceleration (const SimTK::State &state) const
Perform computations that may depend on applied forces. More...

virtual void extendRealizeReport (const SimTK::State &state) const
Perform computations that may depend on anything but are only used for reporting and cannot affect subsequent simulation behavior. More...

void addModelingOption (const std::string &optionName, int maxFlagValue) const
Add a modeling option (integer flag stored in the State) for use by this Component. More...

void addStateVariable (const std::string &stateVariableName, const SimTK::Stage &invalidatesStage=SimTK::Stage::Dynamics, bool isHidden=false) const
Add a continuous system state variable belonging to this Component, and assign a name by which to refer to it. More...

The above method provides a convenient interface to this method, which automatically creates an 'AddedStateVariable' and allocates resources in the SimTK::State for this variable. More...

void addDiscreteVariable (const std::string &discreteVariableName, SimTK::Stage invalidatesStage) const
Add a system discrete variable belonging to this Component, give it a name by which it can be referenced, and declare the lowest Stage that should be invalidated if this variable's value is changed. More...

SimTK::MultibodySystem & updSystem () const
Get writable reference to the MultibodySystem that this component is connected to. More...

int getStateIndex (const std::string &name) const
Get the index of a Component's continuous state variable in the Subsystem for allocations. More...

SimTK::SystemYIndex getStateVariableSystemIndex (const std::string &stateVariableName) const
Get the System Index of a state variable allocated by this Component. More...

const SimTK::DiscreteVariableIndex getDiscreteVariableIndex (const std::string &name) const
Get the index of a Component's discrete variable in the Subsystem for allocations. More...

template<typename T >
PropertyIndex constructSocket (const std::string &name, const std::string &propertyComment)
Construct a specialized Socket for this Component's dependence on another Component. More...

template<typename T , typename CompType = Component>
bool constructOutput (const std::string &name, T(CompType::*const memFunc)(const SimTK::State &) const, const SimTK::Stage &dependsOn=SimTK::Stage::Acceleration)
Construct an output for a member function of the same component. More...

template<typename T , typename CompType = Component>
bool constructOutput (const std::string &name, const T &(CompType::*const memFunc)(const SimTK::State &) const, const SimTK::Stage &dependsOn=SimTK::Stage::Acceleration)
This variant handles component member functions that return the output value by const reference (const T&). More...

template<typename T , typename CompType >
bool constructListOutput (const std::string &name, T(CompType::*const memFunc)(const SimTK::State &, const std::string &channel) const, const SimTK::Stage &dependsOn=SimTK::Stage::Acceleration)
Construct an output that can have multiple channels. More...

bool constructOutputForStateVariable (const std::string &name)
Construct an Output for a StateVariable. More...

template<typename T >
PropertyIndex constructInput (const std::string &name, bool isList, const std::string &propertyComment, const SimTK::Stage &requiredAtStage=SimTK::Stage::Instance)
Construct an Input (socket) for this Component's dependence on an Output signal. More...

template<class T >
CacheVariable< T > addCacheVariable (std::string name, T variablePrototype, SimTK::Stage dependsOnStage) const
Add a state cache entry belonging to this Component to hold calculated values that must be automatically invalidated when certain state values change. More...

void setOwner (const Component &owner)
Set this Component's reference to its owning Component More...

Protected Member Functions inherited from OpenSim::Object
Object ()
The default constructor is only for use by constructors of derived types. More...

Object (const std::string &fileName, bool aUpdateFromXMLNode=true)
Constructor from a file, to be called from other constructors that take a file as input. More...

Object (const Object &source)
Copy constructor is invoked automatically by derived classes with default copy constructors; otherwise it must be invoked explicitly. More...

Object (SimTK::Xml::Element &aElement)
Construct the base class portion of an Object from a given Xml element that describes this Object. More...

template<class T >
PropertyIndex addProperty (const std::string &name, const std::string &comment, const T &value)
Define a new single-value property of known type T, with the given name, associated comment, and initial value. More...

template<class T >
PropertyIndex addOptionalProperty (const std::string &name, const std::string &comment)
Add an optional property, meaning it can contain either no value or a single value. More...

template<class T >
PropertyIndex addOptionalProperty (const std::string &name, const std::string &comment, const T &value)
Add an optional property, meaning it can contain either no value or a single value. More...

template<class T >
PropertyIndex addListProperty (const std::string &name, const std::string &comment, int minSize, int maxSize)
Define a new list-valued property of known type T, with the given name, associated comment, minimum (==0) and maximum (>0) allowable list lengths, and a zero-length initial value. More...

template<class T , template< class > class Container>
PropertyIndex addListProperty (const std::string &name, const std::string &comment, int minSize, int maxSize, const Container< T > &valueList)
Define a new list-valued property as above, but assigning an initial value via some templatized container class that supports size() and indexing. More...

PropertyIndex getPropertyIndex (const std::string &name) const
Look up a property by name and return its PropertyIndex if it is found. More...

template<class T >
PropertyIndex getPropertyIndex () const
Look up an unnamed property by the type of object it contains, and return its PropertyIndex if it is found. More...

template<class T >
void checkPropertyValueIsPositive (const Property< T > &p) const
Throw an exception if any of the property's values are not positive. More...

template<class T >
void checkPropertyValueIsInSet (const Property< T > &p, const std::set< T > &set) const
Throw an exception if any of the property's values are not in the provided set. More...

template<class T >
void checkPropertyValueIsInRangeOrSet (const Property< T > &p, const T &lower, const T &upper, const std::set< T > &set) const
Throw an exception if any of the property's values are neither in the provided range nor in the provided set. More...

void setObjectIsUpToDateWithProperties ()
When an object is initialized using the current values of its properties, it can set a flag indicating that it is up to date. More...

void clearObjectIsUpToDateWithProperties ()
For testing or debugging purposes, manually clear the "object is up to date with respect to properties" flag. More...

void makeObjectNamesConsistentWithProperties ()
Make sure the name of an object is consistent with its property type. More...

void updateFromXMLDocument ()
Use this method only if you're deserializing from a file and the object is at the top level; that is, primarily in constructors that take a file name as input. More...

void setDocument (XMLDocument *doc)
Unconditionally set the XMLDocument associated with this object. More...

const XMLDocumentgetDocument () const
Get a const pointer to the document (if any) associated with this object. More...

XMLDocumentupdDocument ()
Get a writable pointer to the document (if any) associated with this object. More...

## Auto-generated functions

static DeGrooteFregly2016MusclesafeDownCast (OpenSim::Object *obj)
For use in MATLAB and Python to access the concrete class. More...

static const std::string & getClassName ()
This returns "DeGrooteFregly2016Muscle". More...

void assign (Object &aObject) override
This allows copy assignment in the Java GUI. More...

DeGrooteFregly2016Muscleclone () const override
Create a new heap-allocated copy of the concrete object to which this Object refers. More...

const std::string & getConcreteClassName () const override
Returns the class name of the concrete Object-derived class of the actual object referenced by this Object, as a string. More...

## Muscle interface

double getActivation (const SimTK::State &s) const override
If ignore_activation_dynamics is true, this gets excitation instead. More...

void setActivation (SimTK::State &s, double activation) const override
If ignore_activation_dynamics is true, this sets excitation instead. More...

void computeInitialFiberEquilibrium (SimTK::State &s) const override
In this method, calcEquilibriumResidual() is used to find a value of the normalized tendon force state variable that produces muscle-tendon equilibrium. More...

double calcInextensibleTendonActiveFiberForce (SimTK::State &, double) const override

void calcMuscleLengthInfo (const SimTK::State &s, MuscleLengthInfo &mli) const override
calculate muscle's position related values such fiber and tendon lengths, normalized lengths, pennation angle, etc... More...

void calcFiberVelocityInfo (const SimTK::State &s, FiberVelocityInfo &fvi) const override
calculate muscle's fiber velocity and pennation angular velocity, etc... More...

void calcMuscleDynamicsInfo (const SimTK::State &s, MuscleDynamicsInfo &mdi) const override
calculate muscle's active and passive force-length, force-velocity, tendon force, relationships and their related values More...

void calcMusclePotentialEnergyInfo (const SimTK::State &s, MusclePotentialEnergyInfo &mpei) const override
calculate muscle's fiber and tendon potential energy More...

## Get methods.

static std::string getActivationStateName ()

static std::string getNormalizedTendonForceStateName ()

static std::string getImplicitDynamicsDerivativeName ()

static std::string getImplicitDynamicsResidualName ()

static double getMinNormalizedTendonForce ()

static double getMaxNormalizedTendonForce ()

static double getMinNormalizedFiberLength ()

static double getMaxNormalizedFiberLength ()

double getPassiveFiberElasticForce (const SimTK::State &s) const
Get the portion of the passive fiber force generated by the elastic element only (N). More...

double getPassiveFiberElasticForceAlongTendon (const SimTK::State &s) const
Get the portion of the passive fiber force generated by the elastic element only, projected onto the tendon direction (N). More...

double getPassiveFiberDampingForce (const SimTK::State &s) const
Get the portion of the passive fiber force generated by the damping element only (N). More...

double getPassiveFiberDampingForceAlongTendon (const SimTK::State &s) const
Get the portion of the passive fiber force generated by the damping element only, projected onto the tendon direction (N). More...

bool getImplicitEnabledNormalizedTendonForce (const SimTK::State &) const
Get whether fiber dynamics is in implicit dynamics mode when using normalized tendon force as the state. More...

double getImplicitResidualNormalizedTendonForce (const SimTK::State &s) const
Compute the muscle-tendon force equilibrium residual value when using implicit contraction dynamics with normalized tendon force as the state. More...

double getNormalizedTendonForce (const SimTK::State &s) const
If ignore_tendon_compliance is true, this gets normalized fiber force along the tendon instead. More...

double getNormalizedTendonForceDerivative (const SimTK::State &s) const
Obtain the time derivative of the normalized tendon force. More...

double getEquilibriumResidual (const SimTK::State &s) const
The residual (i.e. More...

double getLinearizedEquilibriumResidualDerivative (const SimTK::State &s) const
The residual (i.e. More...

SimTK::Vec2 getBoundsNormalizedTendonForce (const SimTK::State &) const
The first element of the Vec2 is the lower bound, and the second is the upper bound. More...

SimTK::Vec2 getBoundsNormalizedFiberLength () const
The first element of the Vec2 is the lower bound, and the second is the upper bound. More...

## Calculation methods.

These functions compute the values of normalized/dimensionless curves, their derivatives and integrals, and other quantities of the muscle.

These do not depend on a SimTK::State.

static SimTK::Real calcForceVelocityMultiplier (const SimTK::Real &normFiberVelocity)
The parameters of this curve are not modifiable, so this function is static. More...

static SimTK::Real calcForceVelocityInverseCurve (const SimTK::Real &forceVelocityMult)
This is the inverse of the force-velocity multiplier function, and returns the normalized fiber velocity (in [-1, 1]) as a function of the force-velocity multiplier. More...

SimTK::Real calcActiveForceLengthMultiplier (const SimTK::Real &normFiberLength) const
The active force-length curve is the sum of 3 Gaussian-like curves. More...

SimTK::Real calcActiveForceLengthMultiplierDerivative (const SimTK::Real &normFiberLength) const
The derivative of the active force-length curve with respect to normalized fiber length. More...

SimTK::Real calcPassiveForceMultiplier (const SimTK::Real &normFiberLength) const
This is the passive force-length curve. More...

SimTK::Real calcPassiveForceMultiplierDerivative (const SimTK::Real &normFiberLength) const
This is the derivative of the passive force-length curve with respect to the normalized fiber length. More...

SimTK::Real calcPassiveForceMultiplierIntegral (const SimTK::Real &normFiberLength) const
This is the integral of the passive force-length curve with respect to the normalized fiber length over the domain [minNormFiberLength normFiberLength], where minNormFiberLength is the value return by getMinNormalizedFiberLength(). More...

SimTK::Real calcTendonForceMultiplier (const SimTK::Real &normTendonLength) const
The normalized tendon force as a function of normalized tendon length. More...

SimTK::Real calcTendonForceMultiplierDerivative (const SimTK::Real &normTendonLength) const
This is the derivative of the tendon-force length curve with respect to normalized tendon length. More...

SimTK::Real calcTendonForceMultiplierIntegral (const SimTK::Real &normTendonLength) const
This is the integral of the tendon-force length curve with respect to normalized tendon length over the domain [minNormTendonLength normTendonLength]. More...

SimTK::Real calcTendonForceLengthInverseCurve (const SimTK::Real &normTendonForce) const
This is the inverse of the tendon force-length curve, and returns the normalized tendon length as a function of the normalized tendon force. More...

SimTK::Real calcTendonForceLengthInverseCurveDerivative (const SimTK::Real &derivNormTendonForce, const SimTK::Real &normTendonLength) const
This returns normalized tendon velocity given the derivative of normalized tendon force and normalized tendon length. More...

void calcFiberForce (const SimTK::Real &activation, const SimTK::Real &activeForceLengthMultiplier, const SimTK::Real &forceVelocityMultiplier, const SimTK::Real &normPassiveFiberForce, const SimTK::Real &normFiberVelocity, SimTK::Real &activeFiberForce, SimTK::Real &conPassiveFiberForce, SimTK::Real &nonConPassiveFiberForce, SimTK::Real &totalFiberForce) const
This computes both the total fiber force and the individual components of fiber force (active, conservative passive, and non-conservative passive). More...

SimTK::Real calcFiberStiffness (const SimTK::Real &activation, const SimTK::Real &normFiberLength, const SimTK::Real &fiberVelocityMultiplier) const
The stiffness of the fiber in the direction of the fiber. More...

SimTK::Real calcTendonStiffness (const SimTK::Real &normTendonLength) const
The stiffness of the tendon in the direction of the tendon. More...

SimTK::Real calcMuscleStiffness (const SimTK::Real &tendonStiffness, const SimTK::Real &fiberStiffnessAlongTendon) const
The stiffness of the whole musculotendon unit in the direction of the tendon. More...

SimTK::Real calcPartialPennationAnglePartialFiberLength (const SimTK::Real &fiberLength) const
The derivative of pennation angle with respect to fiber length. More...

SimTK::Real calcPartialFiberForceAlongTendonPartialFiberLength (const SimTK::Real &fiberForce, const SimTK::Real &fiberStiffness, const SimTK::Real &sinPennationAngle, const SimTK::Real &cosPennationAngle, const SimTK::Real &partialPennationAnglePartialFiberLength) const
The derivative of the fiber force along the tendon with respect to fiber length. More...

SimTK::Real calcFiberStiffnessAlongTendon (const SimTK::Real &fiberLength, const SimTK::Real &partialFiberForceAlongTendonPartialFiberLength, const SimTK::Real &sinPennationAngle, const SimTK::Real &cosPennationAngle, const SimTK::Real &partialPennationAnglePartialFiberLength) const
The derivative of the fiber force along the tendon with respect to the fiber length along the tendon. More...

SimTK::Real calcPartialTendonLengthPartialFiberLength (const SimTK::Real &fiberLength, const SimTK::Real &sinPennationAngle, const SimTK::Real &cosPennationAngle, const SimTK::Real &partialPennationAnglePartialFiberLength) const

SimTK::Real calcPartialTendonForcePartialFiberLength (const SimTK::Real &tendonStiffness, const SimTK::Real &fiberLength, const SimTK::Real &sinPennationAngle, const SimTK::Real &cosPennationAngle) const

SimTK::Real calcEquilibriumResidual (const SimTK::Real &muscleTendonLength, const SimTK::Real &muscleTendonVelocity, const SimTK::Real &activation, const SimTK::Real &normTendonForce, const SimTK::Real &normTendonForceDerivative) const
The residual (i.e. More...

SimTK::Real calcLinearizedEquilibriumResidualDerivative (const SimTK::Real &muscleTendonLength, const SimTK::Real &muscleTendonVelocity, const SimTK::Real &activation, const SimTK::Real &normTendonForce, const SimTK::Real &normTendonForceDerivative) const
The residual (i.e. More...

## Utilities

static void replaceMuscles (Model &model, bool allowUnsupportedMuscles=false)
Replace muscles of other types in the model with muscles of this type. More...

DataTable exportFiberLengthCurvesToTable (const SimTK::Vector &normFiberLengths=SimTK::Vector()) const
Export the active force-length multiplier and passive force multiplier curves to a DataTable. More...

DataTable exportFiberVelocityMultiplierToTable (const SimTK::Vector &normFiberVelocities=SimTK::Vector()) const
Export the fiber force-velocity multiplier curve to a DataTable. More...

DataTable exportTendonForceMultiplierToTable (const SimTK::Vector &normTendonLengths=SimTK::Vector()) const
Export the fiber tendon force multiplier curve to a DataTable. More...

void printCurvesToSTOFiles (const std::string &directory=".") const
Print the muscle curves to STO files. More...

Static Public Member Functions inherited from OpenSim::Muscle
static MusclesafeDownCast (OpenSim::Object *obj)
For use in MATLAB and Python to access the concrete class. More...

static const std::string & getClassName ()
This returns "Muscle". More...

Static Public Member Functions inherited from OpenSim::PathActuator
static PathActuatorsafeDownCast (OpenSim::Object *obj)
For use in MATLAB and Python to access the concrete class. More...

static const std::string & getClassName ()
This returns "PathActuator". More...

Static Public Member Functions inherited from OpenSim::ScalarActuator
static ScalarActuatorsafeDownCast (OpenSim::Object *obj)
For use in MATLAB and Python to access the concrete class. More...

static const std::string & getClassName ()
This returns "ScalarActuator". More...

Static Public Member Functions inherited from OpenSim::Actuator
static ActuatorsafeDownCast (OpenSim::Object *obj)
For use in MATLAB and Python to access the concrete class. More...

static const std::string & getClassName ()
This returns "Actuator". More...

Static Public Member Functions inherited from OpenSim::Force
static ForcesafeDownCast (OpenSim::Object *obj)
For use in MATLAB and Python to access the concrete class. More...

static const std::string & getClassName ()
This returns "Force". More...

Static Public Member Functions inherited from OpenSim::ModelComponent
static ModelComponentsafeDownCast (OpenSim::Object *obj)
For use in MATLAB and Python to access the concrete class. More...

static const std::string & getClassName ()
This returns "ModelComponent". More...

Static Public Member Functions inherited from OpenSim::Component
static ComponentsafeDownCast (OpenSim::Object *obj)
For use in MATLAB and Python to access the concrete class. More...

static const std::string & getClassName ()
This returns "Component". More...

Static Public Member Functions inherited from OpenSim::Object
static void registerType (const Object &defaultObject)
Register an instance of a class; if the class is already registered it will be replaced. More...

static void renameType (const std::string &oldTypeName, const std::string &newTypeName)
Support versioning by associating the current Object type with an old name. More...

static const ObjectgetDefaultInstanceOfType (const std::string &concreteClassName)
Return a pointer to the default instance of the registered (concrete) Object whose class name is given, or NULL if the type is not registered. More...

template<class T >
static bool isObjectTypeDerivedFrom (const std::string &concreteClassName)
Return true if the given concrete object type represents a subclass of the template object type T, and thus could be referenced with a T*. More...

static ObjectnewInstanceOfType (const std::string &concreteClassName)
Create a new instance of the concrete Object type whose class name is given as concreteClassName. More...

static void getRegisteredTypenames (Array< std::string > &typeNames)
Retrieve all the typenames registered so far. More...

template<class T >
static void getRegisteredObjectsOfGivenType (ArrayPtrs< T > &rArray)
Return an array of pointers to the default instances of all registered (concrete) Object types that derive from a given Object-derived type that does not have to be concrete. More...

static bool PrintPropertyInfo (std::ostream &os, const std::string &classNameDotPropertyName, bool printFlagInfo=true)
Dump formatted property information to a given output stream, useful for creating a "help" facility for registered objects. More...

static bool PrintPropertyInfo (std::ostream &os, const std::string &className, const std::string &propertyName, bool printFlagInfo=true)
Same as the other signature but the class name and property name are provided as two separate strings. More...

static ObjectmakeObjectFromFile (const std::string &fileName)
Create an OpenSim object whose type is based on the tag at the root node of the XML file passed in. More...

static const std::string & getClassName ()
Return the name of this class as a string; i.e., "Object". More...

static void setSerializeAllDefaults (bool shouldSerializeDefaults)
Static function to control whether all registered objects and their properties are written to the defaults section of output files rather than only those values for which the default was explicitly overwritten when read in from an input file or set programmatically. More...

static bool getSerializeAllDefaults ()
Report the value of the "serialize all defaults" flag. More...

static bool isKindOf (const char *type)
Returns true if the passed-in string is "Object"; each Object-derived class defines a method of this name for its own class name. More...

static void setDebugLevel (int newLevel)
Set the amount of logging output. More...

static int getDebugLevel ()
Get the current setting of debug level. More...

static ObjectSafeCopy (const Object *aObject)
Use the clone() method to duplicate the given object unless the pointer is null in which case null is returned. More...

static void RegisterType (const Object &defaultObject)
OBSOLETE alternate name for registerType(). More...

static void RenameType (const std::string &oldName, const std::string &newName)
OBSOLETE alternate name for renameType(). More...

Static Public Attributes inherited from OpenSim::Object
static const std::string DEFAULT_NAME
Name used for default objects when they are serialized. More...

Static Protected Member Functions inherited from OpenSim::Component
static void prependComponentPathToConnecteePath (Component &subcomponent)
For internal use. More...

Protected Attributes inherited from OpenSim::Muscle
double _muscleWidth
The assumed fixed muscle-width from which the fiber pennation angle can be calculated. More...

double _maxIsometricForce
to support deprecated muscles More...

double _optimalFiberLength

double _pennationAngleAtOptimal

double _tendonSlackLength

CacheVariable< Muscle::MuscleLengthInfo_lengthInfoCV

CacheVariable< Muscle::FiberVelocityInfo_velInfoCV

CacheVariable< Muscle::MuscleDynamicsInfo_dynamicsInfoCV

CacheVariable< Muscle::MusclePotentialEnergyInfo_potentialEnergyInfoCV

Protected Attributes inherited from OpenSim::Actuator
int _controlIndex

Protected Attributes inherited from OpenSim::Force
SimTK::ResetOnCopy< SimTK::ForceIndex > _index
ID for the force in Simbody. More...

Protected Attributes inherited from OpenSim::ModelComponent
SimTK::ReferencePtr< Model_model
The model this component belongs to. More...

Protected Attributes inherited from OpenSim::Object
PropertySet _propertySet
OBSOLETE: Property_Deprecated set for serializable member variables of this and derived classes. More...

Static Protected Attributes inherited from OpenSim::ModelComponent
static const SimTK::Vec3 InvalidScaleFactors
Returned by getScaleFactors() if the ScaleSet does not contain scale factors for the base Body associated with the specified Frame. More...

## Detailed Description

This muscle model was published in De Groote et al.

The parameters of the active force-length and force-velocity curves have been slightly modified from what was published to ensure the curves go through key points:

• Active force-length curve goes through (1, 1).
• Force-velocity curve goes through (-1, 0) and (0, 1). The default tendon force curve parameters are modified from that in De Groote et al., 2016: the curve is parameterized by the strain at 1 norm force (rather than "kT"), and the default value for this parameter is 0.049 (same as in TendonForceLengthCurve) rather than 0.0474.

This implementation introduces the property 'active_force_width_scale' as an addition to the original model, which allows users to effectively make the active force-length curve wider. This property may be useful for improving the force-generating capacity of a muscle without increasing maximum isometric force. This property works by scaling the normalized fiber length when the active force-length curve is computed. For example, a scale factor of 2 means that the fiber muscle traverses half as far along the force-length curve in either direction.

This implementation adds fiber damping as an addition to the original model. Users can specify this via the 'fiber_damping' property, and damping force along the fiber is computed by multiplying the property value by the normalized fiber velocity and max isometric force. If using this muscle for optimization, fiber damping is recommended as it can improve convergence.

Note
If converting from Thelen2003Muscles via replaceMuscles(), fiber damping will be set to zero since there is no damping in that muscle model.

This class supports tendon compliance dynamics in both explicit and implicit form (formulations 1 and 3 from De Groote et al. 2016). Both forms of the dynamics use normalized tendon force as the state variable (rather than the typical fiber length state). The explicit form is handled through the usual Component dynamics interface. The implicit form introduces an additional discrete state variable and cache variable in the SimTK::State for the derivative of normalized tendon force and muscle-tendon equilibrium residual respectively. In general, it is preferable to use the implicit form in optimization since it can be robust to arbitrary initial guesses (see De Groote et al. 2016). However, the implicit form is only for use with solvers that support implicit dynamics (i.e. Moco) and cannot be used to perform a time-stepping forward simulation with Manager; use explicit mode for time-stepping.

Note
Normalized tendon force is bounded in the range [0, 5] in this class. The methods getMinNormalizedTendonForce() and getMaxNormalizedTendonForce() provide these bounds for use in custom solvers.

# Departures from the Muscle base class

The documentation for Muscle::MuscleLengthInfo states that the optimalFiberLength of a muscle is also its resting length, but this is not true for this muscle: there is a non-zero passive fiber force at the optimal fiber length.

In the Muscle class, setIgnoreTendonCompliance() and setIngoreActivationDynamics() control modeling options, meaning these settings could theoretically be changed. However, for this class, the modeling option is ignored and the values of the ignore_tendon_compliance and ignore_activation_dynamics properties are used directly.

De Groote, F., Kinney, A. L., Rao, A. V., & Fregly, B. J. (2016). Evaluation of Direct Collocation Optimal Control Problem Formulations for Solving the Muscle Redundancy Problem. Annals of Biomedical Engineering, 44(10), 1–15. http://doi.org/10.1007/s10439-016-1591-9

Examples:
exampleHangingMuscle.cpp.

## ◆ Self

This typedef might be useful within the member functions of this class.

This is generated by the OpenSim_DECLARE_*_OBJECT macros.

## ◆ Super

Use this typedef to refer to the superclass of this class.

Avoid using the explicit type name of the superclass; this would introduce bugs if the superclass is changed.

This is generated by the OpenSim_DECLARE_*_OBJECT macros.

## ◆ DeGrooteFregly2016Muscle()

 OpenSim::DeGrooteFregly2016Muscle::DeGrooteFregly2016Muscle ( )
inline

## ◆ assign()

 void OpenSim::DeGrooteFregly2016Muscle::assign ( Object & aObject )
inlineoverride

This allows copy assignment in the Java GUI.

Exceptions
 Exception if the argument is not of type DeGrooteFregly2016Muscle.

## ◆ calcActiveForceLengthMultiplier()

 SimTK::Real OpenSim::DeGrooteFregly2016Muscle::calcActiveForceLengthMultiplier ( const SimTK::Real & normFiberLength ) const
inline

The active force-length curve is the sum of 3 Gaussian-like curves.

The width of the curve can be adjusted via the 'active_force_width_scale' property.

## ◆ calcActiveForceLengthMultiplierDerivative()

 SimTK::Real OpenSim::DeGrooteFregly2016Muscle::calcActiveForceLengthMultiplierDerivative ( const SimTK::Real & normFiberLength ) const
inline

The derivative of the active force-length curve with respect to normalized fiber length.

This curve is based on the derivative of the Gaussian-like curve used in calcActiveForceLengthMultiplier(). The 'active_force_width_scale' property also affects the value of the derivative curve.

## ◆ calcEquilibriumResidual()

 SimTK::Real OpenSim::DeGrooteFregly2016Muscle::calcEquilibriumResidual ( const SimTK::Real & muscleTendonLength, const SimTK::Real & muscleTendonVelocity, const SimTK::Real & activation, const SimTK::Real & normTendonForce, const SimTK::Real & normTendonForceDerivative ) const
inline

The residual (i.e.

error) in the muscle-tendon equilibrium equation: residual = normTendonForce - normFiberForce * cosPennationAngle The residual is unitless (units of normalized force). This is computed using the muscle in implicit mode, since explicit mode uses the normalized tendon force state variable directly to compute fiber force, which always produces a zero muscle-tendon equilibrium residual.

## ◆ calcFiberForce()

 void OpenSim::DeGrooteFregly2016Muscle::calcFiberForce ( const SimTK::Real & activation, const SimTK::Real & activeForceLengthMultiplier, const SimTK::Real & forceVelocityMultiplier, const SimTK::Real & normPassiveFiberForce, const SimTK::Real & normFiberVelocity, SimTK::Real & activeFiberForce, SimTK::Real & conPassiveFiberForce, SimTK::Real & nonConPassiveFiberForce, SimTK::Real & totalFiberForce ) const
inline

This computes both the total fiber force and the individual components of fiber force (active, conservative passive, and non-conservative passive).

Note
based on Millard2012EquilibriumMuscle::calcFiberForce().

## ◆ calcFiberStiffness()

 SimTK::Real OpenSim::DeGrooteFregly2016Muscle::calcFiberStiffness ( const SimTK::Real & activation, const SimTK::Real & normFiberLength, const SimTK::Real & fiberVelocityMultiplier ) const
inline

The stiffness of the fiber in the direction of the fiber.

This includes both active and passive force contributions to stiffness from the muscle fiber.

Note
based on Millard2012EquilibriumMuscle::calcFiberStiffness().

## ◆ calcFiberStiffnessAlongTendon()

 SimTK::Real OpenSim::DeGrooteFregly2016Muscle::calcFiberStiffnessAlongTendon ( const SimTK::Real & fiberLength, const SimTK::Real & partialFiberForceAlongTendonPartialFiberLength, const SimTK::Real & sinPennationAngle, const SimTK::Real & cosPennationAngle, const SimTK::Real & partialPennationAnglePartialFiberLength ) const
inline

The derivative of the fiber force along the tendon with respect to the fiber length along the tendon.

Note
based on Millard2012EquilibriumMuscle::calc_DFiberForceAT_DFiberLengthAT.

## ◆ calcFiberVelocityInfo()

 void OpenSim::DeGrooteFregly2016Muscle::calcFiberVelocityInfo ( const SimTK::State & s, FiberVelocityInfo & fvi ) const
overrideprotectedvirtual

calculate muscle's fiber velocity and pennation angular velocity, etc...

Reimplemented from OpenSim::Muscle.

## ◆ calcForceVelocityInverseCurve()

 static SimTK::Real OpenSim::DeGrooteFregly2016Muscle::calcForceVelocityInverseCurve ( const SimTK::Real & forceVelocityMult )
inlinestatic

This is the inverse of the force-velocity multiplier function, and returns the normalized fiber velocity (in [-1, 1]) as a function of the force-velocity multiplier.

## ◆ calcForceVelocityMultiplier()

 static SimTK::Real OpenSim::DeGrooteFregly2016Muscle::calcForceVelocityMultiplier ( const SimTK::Real & normFiberVelocity )
inlinestatic

The parameters of this curve are not modifiable, so this function is static.

Domain: [-1, 1] Range: [0, 1.794]

Note
It is upon the user to check that the muscle fiber is acting within the specified domain. Force computations outside this range may be incorrect.

## ◆ calcInextensibleTendonActiveFiberForce()

 double OpenSim::DeGrooteFregly2016Muscle::calcInextensibleTendonActiveFiberForce ( SimTK::State & , double ) const
overrideprotected

## ◆ calcLinearizedEquilibriumResidualDerivative()

 SimTK::Real OpenSim::DeGrooteFregly2016Muscle::calcLinearizedEquilibriumResidualDerivative ( const SimTK::Real & muscleTendonLength, const SimTK::Real & muscleTendonVelocity, const SimTK::Real & activation, const SimTK::Real & normTendonForce, const SimTK::Real & normTendonForceDerivative ) const
inline

The residual (i.e.

error) in the time derivative of the linearized muscle-tendon equilibrium equation (Millard et al. 2013, equation A6): residual = fiberStiffnessAlongTendon * fiberVelocityAlongTendon - tendonStiffness * (muscleTendonVelocity - fiberVelocityAlongTendon) This may be useful for finding equilibrium when there is velocity in the muscle-tendon actuator. Velocity is divided between the muscle and tendon based on their relative stiffnesses.

## ◆ calcMuscleDynamicsInfo()

 void OpenSim::DeGrooteFregly2016Muscle::calcMuscleDynamicsInfo ( const SimTK::State & s, MuscleDynamicsInfo & mdi ) const
overrideprotectedvirtual

calculate muscle's active and passive force-length, force-velocity, tendon force, relationships and their related values

Reimplemented from OpenSim::Muscle.

## ◆ calcMuscleLengthInfo()

 void OpenSim::DeGrooteFregly2016Muscle::calcMuscleLengthInfo ( const SimTK::State & s, MuscleLengthInfo & mli ) const
overrideprotectedvirtual

calculate muscle's position related values such fiber and tendon lengths, normalized lengths, pennation angle, etc...

Reimplemented from OpenSim::Muscle.

## ◆ calcMusclePotentialEnergyInfo()

 void OpenSim::DeGrooteFregly2016Muscle::calcMusclePotentialEnergyInfo ( const SimTK::State & s, MusclePotentialEnergyInfo & mpei ) const
overrideprotectedvirtual

calculate muscle's fiber and tendon potential energy

Reimplemented from OpenSim::Muscle.

## ◆ calcMuscleStiffness()

 SimTK::Real OpenSim::DeGrooteFregly2016Muscle::calcMuscleStiffness ( const SimTK::Real & tendonStiffness, const SimTK::Real & fiberStiffnessAlongTendon ) const
inline

The stiffness of the whole musculotendon unit in the direction of the tendon.

Note
based on Millard2012EquilibriumMuscle.

## ◆ calcPartialFiberForceAlongTendonPartialFiberLength()

 SimTK::Real OpenSim::DeGrooteFregly2016Muscle::calcPartialFiberForceAlongTendonPartialFiberLength ( const SimTK::Real & fiberForce, const SimTK::Real & fiberStiffness, const SimTK::Real & sinPennationAngle, const SimTK::Real & cosPennationAngle, const SimTK::Real & partialPennationAnglePartialFiberLength ) const
inline

The derivative of the fiber force along the tendon with respect to fiber length.

Note
based on Millard2012EquilibriumMuscle::calc_DFiberForceAT_DFiberLength().

## ◆ calcPartialPennationAnglePartialFiberLength()

 SimTK::Real OpenSim::DeGrooteFregly2016Muscle::calcPartialPennationAnglePartialFiberLength ( const SimTK::Real & fiberLength ) const
inline

The derivative of pennation angle with respect to fiber length.

Note
based on MuscleFixedWidthPennationModel::calc_DPennationAngle_DFiberLength().

## ◆ calcPartialTendonForcePartialFiberLength()

 SimTK::Real OpenSim::DeGrooteFregly2016Muscle::calcPartialTendonForcePartialFiberLength ( const SimTK::Real & tendonStiffness, const SimTK::Real & fiberLength, const SimTK::Real & sinPennationAngle, const SimTK::Real & cosPennationAngle ) const
inline

## ◆ calcPartialTendonLengthPartialFiberLength()

 SimTK::Real OpenSim::DeGrooteFregly2016Muscle::calcPartialTendonLengthPartialFiberLength ( const SimTK::Real & fiberLength, const SimTK::Real & sinPennationAngle, const SimTK::Real & cosPennationAngle, const SimTK::Real & partialPennationAnglePartialFiberLength ) const
inline

## ◆ calcPassiveForceMultiplier()

 SimTK::Real OpenSim::DeGrooteFregly2016Muscle::calcPassiveForceMultiplier ( const SimTK::Real & normFiberLength ) const
inline

This is the passive force-length curve.

The curve becomes negative below the minNormFiberLength.

We modified this equation from that in the supplementary materials of De Groote et al., 2016, which is the same function used in Thelen2003Muscle. The version in the supplementary materials passes through y = 0 at x = 1.0 and allows for negative forces. We do not want negative forces within the allowed range of fiber lengths, so we modified the equation to pass through y = 0 at x = minNormFiberLength. (This is not an issue for Thelen2003Muscle because the curve is not smooth and returns 0 for lengths less than optimal fiber length.)

## ◆ calcPassiveForceMultiplierDerivative()

 SimTK::Real OpenSim::DeGrooteFregly2016Muscle::calcPassiveForceMultiplierDerivative ( const SimTK::Real & normFiberLength ) const
inline

This is the derivative of the passive force-length curve with respect to the normalized fiber length.

## ◆ calcPassiveForceMultiplierIntegral()

 SimTK::Real OpenSim::DeGrooteFregly2016Muscle::calcPassiveForceMultiplierIntegral ( const SimTK::Real & normFiberLength ) const
inline

This is the integral of the passive force-length curve with respect to the normalized fiber length over the domain [minNormFiberLength normFiberLength], where minNormFiberLength is the value return by getMinNormalizedFiberLength().

## ◆ calcTendonForceLengthInverseCurve()

 SimTK::Real OpenSim::DeGrooteFregly2016Muscle::calcTendonForceLengthInverseCurve ( const SimTK::Real & normTendonForce ) const
inline

This is the inverse of the tendon force-length curve, and returns the normalized tendon length as a function of the normalized tendon force.

## ◆ calcTendonForceLengthInverseCurveDerivative()

 SimTK::Real OpenSim::DeGrooteFregly2016Muscle::calcTendonForceLengthInverseCurveDerivative ( const SimTK::Real & derivNormTendonForce, const SimTK::Real & normTendonLength ) const
inline

This returns normalized tendon velocity given the derivative of normalized tendon force and normalized tendon length.

This is derived by taking the derivative of the tendon force multiplier curve with respect to time and then solving for normalized fiber velocity (see supplementary information for De Groote et al. 2016).

## ◆ calcTendonForceMultiplier()

 SimTK::Real OpenSim::DeGrooteFregly2016Muscle::calcTendonForceMultiplier ( const SimTK::Real & normTendonLength ) const
inline

The normalized tendon force as a function of normalized tendon length.

Note that this curve does not go through (1, 0); when normTendonLength=1, this function returns a slightly negative number.

## ◆ calcTendonForceMultiplierDerivative()

 SimTK::Real OpenSim::DeGrooteFregly2016Muscle::calcTendonForceMultiplierDerivative ( const SimTK::Real & normTendonLength ) const
inline

This is the derivative of the tendon-force length curve with respect to normalized tendon length.

## ◆ calcTendonForceMultiplierIntegral()

 SimTK::Real OpenSim::DeGrooteFregly2016Muscle::calcTendonForceMultiplierIntegral ( const SimTK::Real & normTendonLength ) const
inline

This is the integral of the tendon-force length curve with respect to normalized tendon length over the domain [minNormTendonLength normTendonLength].

The lower bound on the domain is computed by passing the value return by getMinNormalizedTendonForce() to calcTendonForceLengthInverseCurve().

## ◆ calcTendonStiffness()

 SimTK::Real OpenSim::DeGrooteFregly2016Muscle::calcTendonStiffness ( const SimTK::Real & normTendonLength ) const
inline

The stiffness of the tendon in the direction of the tendon.

Note
based on Millard2012EquilibriumMuscle.

## ◆ clone()

 DeGrooteFregly2016Muscle* OpenSim::DeGrooteFregly2016Muscle::clone ( ) const
inlineoverridevirtual

Create a new heap-allocated copy of the concrete object to which this Object refers.

It is up to the caller to delete the returned object when no longer needed. Every concrete object deriving from Object implements this pure virtual method automatically, via the declaration macro it invokes (e.g., OpenSim_DECLARE_CONCRETE_OBJECT()). Note that the concrete class overrides modify the return type to be a pointer to the concrete object; that still overrides the base class method because the return type is covariant with (that is, derives from) Object.

Implements OpenSim::Muscle.

## ◆ computeActuation()

 double OpenSim::DeGrooteFregly2016Muscle::computeActuation ( const SimTK::State & s ) const
overrideprotectedvirtual

Actuator interface for a muscle computes the tension in the muscle and applied by the tendon to bones (i.e.

not the fiber force)

Implements OpenSim::Muscle.

## ◆ computeInitialFiberEquilibrium()

 void OpenSim::DeGrooteFregly2016Muscle::computeInitialFiberEquilibrium ( SimTK::State & s ) const
overridevirtual

In this method, calcEquilibriumResidual() is used to find a value of the normalized tendon force state variable that produces muscle-tendon equilibrium.

This relies on the implicit form of tendon compliance since the explicit form uses the normalized tendon force state variable directly to compute fiber force, which always produces a zero muscle-tendon equilibrium residual. The derivative of normalized tendon force is set to zero since a value is required for the implicit form of the model.

Implements OpenSim::Muscle.

## ◆ computeStateVariableDerivatives()

 void OpenSim::DeGrooteFregly2016Muscle::computeStateVariableDerivatives ( const SimTK::State & s ) const
overrideprotectedvirtual

If a model component has allocated any continuous state variables using the addStateVariable() method, then computeStateVariableDerivatives() must be implemented to provide time derivatives for those states.

Override to set the derivatives of state variables added to the system by this component. (also see extendAddToSystem()). If the component adds states and computeStateVariableDerivatives is not implemented by the component, an exception is thrown when the system tries to evaluate its derivatives.

Implement like this:

void computeStateVariableDerivatives(const SimTK::State& state) const {
// Let the parent class set the derivative values for the
// the state variables that it added.
// Compute derivative values for states allocated by this component
// as a function of the state.
double deriv = ...
// Then set the derivative value by state variable name
setStateVariableDerivativeValue(state, "<state_variable_name>", deriv);
}

For subclasses, it is highly recommended that you first call Super::computeStateVariableDerivatives(state) to preserve the derivative computation of the parent class and to only specify the derivatives of the state variables added by name. One does have the option to override all the derivative values for the parent by accessing the derivatives by their state variable name. This is necessary, for example, if a newly added state variable is coupled to the dynamics (derivatives) of the states variables that were added by the parent.

Reimplemented from OpenSim::Component.

## ◆ exportFiberLengthCurvesToTable()

 DataTable OpenSim::DeGrooteFregly2016Muscle::exportFiberLengthCurvesToTable ( const SimTK::Vector & normFiberLengths = SimTK::Vector() ) const

Export the active force-length multiplier and passive force multiplier curves to a DataTable.

If the normFiberLengths argument is omitted, we use createVectorLinspace(200, minNormFiberLength, maxNormFiberLength).

## ◆ exportFiberVelocityMultiplierToTable()

 DataTable OpenSim::DeGrooteFregly2016Muscle::exportFiberVelocityMultiplierToTable ( const SimTK::Vector & normFiberVelocities = SimTK::Vector() ) const

Export the fiber force-velocity multiplier curve to a DataTable.

If the normFiberVelocities argument is omitted, we use createVectorLinspace(200, -1.1, 1.1).

## ◆ exportTendonForceMultiplierToTable()

 DataTable OpenSim::DeGrooteFregly2016Muscle::exportTendonForceMultiplierToTable ( const SimTK::Vector & normTendonLengths = SimTK::Vector() ) const

Export the fiber tendon force multiplier curve to a DataTable.

If the normFiberVelocities argument is omitted, we use createVectorLinspace(200, 0.95, 1 + <strain at 1 norm force>)

 void OpenSim::DeGrooteFregly2016Muscle::extendAddToSystem ( SimTK::MultibodySystem & system ) const
overrideprotectedvirtual

Add appropriate Simbody elements (if needed) to the System corresponding to this component and specify needed state resources.

extendAddToSystem() is called when the Simbody System is being created to represent a completed system (model) for computation. That is, connect() will already have been invoked on all components before any addToSystem() call is made. Helper methods for adding modeling options, state variables and their derivatives, discrete variables, and cache entries are available and can be called within extendAddToSystem() only.

Note that this method is const; you may not modify your model component or the containing model during this call. Any modifications you need should instead be performed in finalizeFromProperties() or at the latest connect(), which are non-const. The only exception is that you may need to record access information for resources you create in the system, such as an index number. For most Components, OpenSim base classes either provide convenience methods or handle indices automatically. Otherwise, you must declare indices as mutable data members so that you can set them here.

If you override this method, be sure to invoke the base class method at the beginning, using code like this:

// ... your code goes here
}

This method assumes that this Component's addToSystem will be invoked before its subcomponents. If you need your subcomponents to be added to the system, first (e.g. require of a Force to be anchored to a SimTK::MobilizedBody specified by subcomponents) then you must implement: extendAddToSystemAfterSubcomponents(). It is possible to implement both method to add system elements before and then after your subcomponents have added themselves. Caution is required that Simbody elements are not added twice especially when order is unimportant.

Parameters
 [in,out] system The MultibodySystem being added to.

Reimplemented from OpenSim::Component.

## ◆ extendFinalizeFromProperties()

 void OpenSim::DeGrooteFregly2016Muscle::extendFinalizeFromProperties ( )
overrideprotectedvirtual

Perform any time-invariant calculations, data structure initializations, or other configuration based on the component's properties to form a functioning (but not yet connected) component.

For example, each property should be checked to ensure that its value is within an acceptable range. When this method returns, the component will be marked as being up-to-date with its properties. Do not perform any configuration that depends on the SimTK::MultibodySystem; it is not available at this point.

If you override this method, be sure to invoke the base class method first, using code like this:

void MyComponent::extendFinalizeFromProperties() {
Super::extendFinalizeFromProperties(); // invoke parent class method
// ... your code goes here
// ... catch invalid property values
// ... initialize any internal data structures
}

Reimplemented from OpenSim::Component.

## ◆ extendInitStateFromProperties()

 void OpenSim::DeGrooteFregly2016Muscle::extendInitStateFromProperties ( SimTK::State & state ) const
overrideprotectedvirtual

Transfer property values or other state-independent initial values into this component's state variables in the passed-in state argument.

This is called after a SimTK::System and State have been created for the Model (that is, after extendAddToSystem() has been called on all components). You should override this method if your component has properties (serializable values) that can affect initial values for your state variables. You can also perform any other state-independent calculations here that result in state initial conditions.

If you override this method, be sure to invoke the base class method first, using code like this:

void MyComponent::extendInitStateFromProperties(SimTK::State& state) const {
Super::extendInitStateFromProperties(state); // invoke parent class method
// ... your code goes here
}
Parameters
 state The state that will receive the new initial conditions.
extendSetPropertiesFromState()

Reimplemented from OpenSim::Component.

## ◆ extendSetPropertiesFromState()

 void OpenSim::DeGrooteFregly2016Muscle::extendSetPropertiesFromState ( const SimTK::State & state )
overrideprotectedvirtual

Update this component's property values to match the specified State, if the component has created any state variable that is intended to correspond to a property.

Thus, state variable values can persist as part of the model component and be serialized as a property.

If you override this method, be sure to invoke the base class method first, using code like this:

void MyComponent::extendSetPropertiesFromState(const SimTK::State& state) {
Super::extendSetPropertiesFromState(state); // invoke parent class method
// ... your code goes here
}
Parameters
 state The State from which values may be extracted to set persistent property values.
extendInitStateFromProperties()

Reimplemented from OpenSim::Component.

## ◆ get_activation_time_constant()

 const double& OpenSim::DeGrooteFregly2016Muscle::get_activation_time_constant ( ) const
inline

Get the value of the activation_time_constant property.

## ◆ get_active_force_width_scale()

 const double& OpenSim::DeGrooteFregly2016Muscle::get_active_force_width_scale ( ) const
inline

Get the value of the active_force_width_scale property.

## ◆ get_deactivation_time_constant()

 const double& OpenSim::DeGrooteFregly2016Muscle::get_deactivation_time_constant ( ) const
inline

Get the value of the deactivation_time_constant property.

## ◆ get_default_activation()

 const double& OpenSim::DeGrooteFregly2016Muscle::get_default_activation ( ) const
inline

Get the value of the default_activation property.

## ◆ get_default_normalized_tendon_force()

 const double& OpenSim::DeGrooteFregly2016Muscle::get_default_normalized_tendon_force ( ) const
inline

Get the value of the default_normalized_tendon_force property.

## ◆ get_fiber_damping()

 const double& OpenSim::DeGrooteFregly2016Muscle::get_fiber_damping ( ) const
inline

Get the value of the fiber_damping property.

## ◆ get_ignore_passive_fiber_force()

 const bool& OpenSim::DeGrooteFregly2016Muscle::get_ignore_passive_fiber_force ( ) const
inline

Get the value of the ignore_passive_fiber_force property.

## ◆ get_passive_fiber_strain_at_one_norm_force()

 const double& OpenSim::DeGrooteFregly2016Muscle::get_passive_fiber_strain_at_one_norm_force ( ) const
inline

Get the value of the passive_fiber_strain_at_one_norm_force property.

## ◆ get_tendon_compliance_dynamics_mode()

 const std::string& OpenSim::DeGrooteFregly2016Muscle::get_tendon_compliance_dynamics_mode ( ) const
inline

Get the value of the tendon_compliance_dynamics_mode property.

## ◆ get_tendon_strain_at_one_norm_force()

 const double& OpenSim::DeGrooteFregly2016Muscle::get_tendon_strain_at_one_norm_force ( ) const
inline

Get the value of the tendon_strain_at_one_norm_force property.

## ◆ getActivation()

 double OpenSim::DeGrooteFregly2016Muscle::getActivation ( const SimTK::State & s ) const
inlineoverridevirtual

If ignore_activation_dynamics is true, this gets excitation instead.

Reimplemented from OpenSim::Muscle.

## ◆ getActivationStateName()

 static std::string OpenSim::DeGrooteFregly2016Muscle::getActivationStateName ( )
inlinestatic

## ◆ getBoundsNormalizedFiberLength()

 SimTK::Vec2 OpenSim::DeGrooteFregly2016Muscle::getBoundsNormalizedFiberLength ( ) const
inline

The first element of the Vec2 is the lower bound, and the second is the upper bound.

Note that since fiber length is not used as a state variable, these bounds cannot be enforced directly. It is upon the user to ensure the muscle fiber is operating within the specified domain.

## ◆ getBoundsNormalizedTendonForce()

 SimTK::Vec2 OpenSim::DeGrooteFregly2016Muscle::getBoundsNormalizedTendonForce ( const SimTK::State & ) const
inline

The first element of the Vec2 is the lower bound, and the second is the upper bound.

This function is intended primarily for the model Output 'statebounds_normalized_tendon_force'. We don't need the state, but the state parameter is a requirement of Output functions.

## ◆ getClassName()

 static const std::string& OpenSim::DeGrooteFregly2016Muscle::getClassName ( )
inlinestatic

This returns "DeGrooteFregly2016Muscle".

See getConcreteClassName() if you want the class name of the underlying concrete object instead.

This is generated by the OpenSim_DECLARE_*_OBJECT macros.

## ◆ getConcreteClassName()

 const std::string& OpenSim::DeGrooteFregly2016Muscle::getConcreteClassName ( ) const
inlineoverridevirtual

Returns the class name of the concrete Object-derived class of the actual object referenced by this Object, as a string.

This is the string that is used as the tag for this concrete object in an XML file. Every concrete class derived from Object automatically overrides this method via the declaration macro it uses. See getClassName() to get the class name of the referencing (possibly abstract) class rather than the concrete object.

getClassName()

Implements OpenSim::Muscle.

## ◆ getEquilibriumResidual()

 double OpenSim::DeGrooteFregly2016Muscle::getEquilibriumResidual ( const SimTK::State & s ) const
inline

The residual (i.e.

error) in the muscle-tendon equilibrium equation: residual = normTendonForce - normFiberForce * cosPennationAngle The residual is unitless (units of normalized force). This is computed using the muscle in implicit mode, since explicit mode uses the normalized tendon force state variable directly to compute fiber force, which always produces a zero muscle-tendon equilibrium residual. This calls calcEquilibriumResidual() using values from the provided SimTK::State as arguments. While is computed using implicit mode, the value of normalized tendon force derivative used is consistent with the property tendon_compliance_dynamics_mode (see getNormalizedTendonForceDerivative()).

## ◆ getImplicitDynamicsDerivativeName()

 static std::string OpenSim::DeGrooteFregly2016Muscle::getImplicitDynamicsDerivativeName ( )
inlinestatic

## ◆ getImplicitDynamicsResidualName()

 static std::string OpenSim::DeGrooteFregly2016Muscle::getImplicitDynamicsResidualName ( )
inlinestatic

## ◆ getImplicitEnabledNormalizedTendonForce()

 bool OpenSim::DeGrooteFregly2016Muscle::getImplicitEnabledNormalizedTendonForce ( const SimTK::State & ) const
inline

Get whether fiber dynamics is in implicit dynamics mode when using normalized tendon force as the state.

This is useful to indicate to solvers to handle the normalized tendon force derivative and muscle-tendon equilibrium variables, which are added to the State as discrete and cache variables, respectively. This function is intended primarily for the model Output 'implicitenabled_normalized_tendon_force'. We don't need the state, but the state parameter is a requirement of Output functions.

## ◆ getImplicitResidualNormalizedTendonForce()

 double OpenSim::DeGrooteFregly2016Muscle::getImplicitResidualNormalizedTendonForce ( const SimTK::State & s ) const

Compute the muscle-tendon force equilibrium residual value when using implicit contraction dynamics with normalized tendon force as the state.

This function is intended primarily for the model Output 'implicitresidual_normalized_tendon_force'.

## ◆ getLinearizedEquilibriumResidualDerivative()

 double OpenSim::DeGrooteFregly2016Muscle::getLinearizedEquilibriumResidualDerivative ( const SimTK::State & s ) const
inline

The residual (i.e.

error) in the time derivative of the linearized muscle-tendon equilibrium equation (Millard et al. 2013, equation A6): residual = fiberStiffnessAlongTendon * fiberVelocityAlongTendon - tendonStiffness * (muscleTendonVelocity - fiberVelocityAlongTendon) This may be useful for finding equilibrium when there is velocity in the muscle-tendon actuator. Velocity is divided between the muscle and tendon based on their relative stiffnesses.

## ◆ getMaxNormalizedFiberLength()

 static double OpenSim::DeGrooteFregly2016Muscle::getMaxNormalizedFiberLength ( )
inlinestatic

## ◆ getMaxNormalizedTendonForce()

 static double OpenSim::DeGrooteFregly2016Muscle::getMaxNormalizedTendonForce ( )
inlinestatic

## ◆ getMinNormalizedFiberLength()

 static double OpenSim::DeGrooteFregly2016Muscle::getMinNormalizedFiberLength ( )
inlinestatic

## ◆ getMinNormalizedTendonForce()

 static double OpenSim::DeGrooteFregly2016Muscle::getMinNormalizedTendonForce ( )
inlinestatic

## ◆ getNormalizedTendonForce()

 double OpenSim::DeGrooteFregly2016Muscle::getNormalizedTendonForce ( const SimTK::State & s ) const
inline

If ignore_tendon_compliance is true, this gets normalized fiber force along the tendon instead.

## ◆ getNormalizedTendonForceDerivative()

 double OpenSim::DeGrooteFregly2016Muscle::getNormalizedTendonForceDerivative ( const SimTK::State & s ) const
inline

Obtain the time derivative of the normalized tendon force.

• If ignore_tendon_compliance is false, this returns zero.
• If tendon_compliance_dynamics_mode is 'implicit', this gets the discrete variable normalized tendon force derivative value.
• If tendon_compliance_dynamics_mode is 'explicit', this gets the value returned by getStateVariableDerivativeValue() for the 'normalized_tendon_force' state.

## ◆ getNormalizedTendonForceStateName()

 static std::string OpenSim::DeGrooteFregly2016Muscle::getNormalizedTendonForceStateName ( )
inlinestatic

## ◆ getPassiveFiberDampingForce()

 double OpenSim::DeGrooteFregly2016Muscle::getPassiveFiberDampingForce ( const SimTK::State & s ) const

Get the portion of the passive fiber force generated by the damping element only (N).

## ◆ getPassiveFiberDampingForceAlongTendon()

 double OpenSim::DeGrooteFregly2016Muscle::getPassiveFiberDampingForceAlongTendon ( const SimTK::State & s ) const

Get the portion of the passive fiber force generated by the damping element only, projected onto the tendon direction (N).

## ◆ getPassiveFiberElasticForce()

 double OpenSim::DeGrooteFregly2016Muscle::getPassiveFiberElasticForce ( const SimTK::State & s ) const

Get the portion of the passive fiber force generated by the elastic element only (N).

## ◆ getPassiveFiberElasticForceAlongTendon()

 double OpenSim::DeGrooteFregly2016Muscle::getPassiveFiberElasticForceAlongTendon ( const SimTK::State & s ) const

Get the portion of the passive fiber force generated by the elastic element only, projected onto the tendon direction (N).

## ◆ printCurvesToSTOFiles()

 void OpenSim::DeGrooteFregly2016Muscle::printCurvesToSTOFiles ( const std::string & directory = "." ) const

Print the muscle curves to STO files.

The files will be named as <muscle-name>_<curve_type>.sto.

Parameters
 directory The directory to which the data files should be written. Do NOT include the filename. By default, the files are printed to the current working directory.

## ◆ replaceMuscles()

 static void OpenSim::DeGrooteFregly2016Muscle::replaceMuscles ( Model & model, bool allowUnsupportedMuscles = false )
static

Replace muscles of other types in the model with muscles of this type.

Currently, only Millard2012EquilibriumMuscles and Thelen2003Muscles are replaced. For these two muscle classes, we copy property values into equivalent properties of the newly created DeGrooteFregly2016Muscle. If the model has muscles of other types, an exception is thrown unless allowUnsupportedMuscles is true, in which a DeGrooteFregly2016Muscle is created using only the base Muscle class property values. Since the DeGrooteFregly2016Muscle implements tendon compliance dynamics with normalized tendon force as the state variable, this function ignores the 'default_fiber_length' property in replaced muscles.

## ◆ safeDownCast()

 static DeGrooteFregly2016Muscle* OpenSim::DeGrooteFregly2016Muscle::safeDownCast ( OpenSim::Object * obj )
inlinestatic

For use in MATLAB and Python to access the concrete class.

Example: cObj = DeGrooteFregly2016Muscle.safeDownCast(obj). This is equivalent to dynamic_cast<DeGrooteFregly2016Muscle*>(obj)` in C++.

## ◆ set_activation_time_constant()

 void OpenSim::DeGrooteFregly2016Muscle::set_activation_time_constant ( const double & value )
inline

Set the value of the activation_time_constant property.

## ◆ set_active_force_width_scale()

 void OpenSim::DeGrooteFregly2016Muscle::set_active_force_width_scale ( const double & value )
inline

Set the value of the active_force_width_scale property.

## ◆ set_deactivation_time_constant()

 void OpenSim::DeGrooteFregly2016Muscle::set_deactivation_time_constant ( const double & value )
inline

Set the value of the deactivation_time_constant property.

## ◆ set_default_activation()

 void OpenSim::DeGrooteFregly2016Muscle::set_default_activation ( const double & value )
inline

Set the value of the default_activation property.

## ◆ set_default_normalized_tendon_force()

 void OpenSim::DeGrooteFregly2016Muscle::set_default_normalized_tendon_force ( const double & value )
inline

Set the value of the default_normalized_tendon_force property.

## ◆ set_fiber_damping()

 void OpenSim::DeGrooteFregly2016Muscle::set_fiber_damping ( const double & value )
inline

Set the value of the fiber_damping property.

## ◆ set_ignore_passive_fiber_force()

 void OpenSim::DeGrooteFregly2016Muscle::set_ignore_passive_fiber_force ( const bool & value )
inline

Set the value of the ignore_passive_fiber_force property.

## ◆ set_passive_fiber_strain_at_one_norm_force()

 void OpenSim::DeGrooteFregly2016Muscle::set_passive_fiber_strain_at_one_norm_force ( const double & value )
inline

Set the value of the passive_fiber_strain_at_one_norm_force property.

## ◆ set_tendon_compliance_dynamics_mode()

 void OpenSim::DeGrooteFregly2016Muscle::set_tendon_compliance_dynamics_mode ( const std::string & value )
inline

Set the value of the tendon_compliance_dynamics_mode property.

## ◆ set_tendon_strain_at_one_norm_force()

 void OpenSim::DeGrooteFregly2016Muscle::set_tendon_strain_at_one_norm_force ( const double & value )
inline

Set the value of the tendon_strain_at_one_norm_force property.

## ◆ setActivation()

 void OpenSim::DeGrooteFregly2016Muscle::setActivation ( SimTK::State & s, double activation ) const
inlineoverridevirtual

If ignore_activation_dynamics is true, this sets excitation instead.

Implements OpenSim::Muscle.

## ◆ setNormalizedTendonForce()

 void OpenSim::DeGrooteFregly2016Muscle::setNormalizedTendonForce ( SimTK::State & s, double normTendonForce ) const
inline

## ◆ upd_activation_time_constant()

 double& OpenSim::DeGrooteFregly2016Muscle::upd_activation_time_constant ( )
inline

Get a writable reference to the activation_time_constant property.

## ◆ upd_active_force_width_scale()

 double& OpenSim::DeGrooteFregly2016Muscle::upd_active_force_width_scale ( )
inline

Get a writable reference to the active_force_width_scale property.

## ◆ upd_deactivation_time_constant()

 double& OpenSim::DeGrooteFregly2016Muscle::upd_deactivation_time_constant ( )
inline

Get a writable reference to the deactivation_time_constant property.

## ◆ upd_default_activation()

 double& OpenSim::DeGrooteFregly2016Muscle::upd_default_activation ( )
inline

Get a writable reference to the default_activation property.

## ◆ upd_default_normalized_tendon_force()

 double& OpenSim::DeGrooteFregly2016Muscle::upd_default_normalized_tendon_force ( )
inline

Get a writable reference to the default_normalized_tendon_force property.

## ◆ upd_fiber_damping()

 double& OpenSim::DeGrooteFregly2016Muscle::upd_fiber_damping ( )
inline

Get a writable reference to the fiber_damping property.

## ◆ upd_ignore_passive_fiber_force()

 bool& OpenSim::DeGrooteFregly2016Muscle::upd_ignore_passive_fiber_force ( )
inline

Get a writable reference to the ignore_passive_fiber_force property.

## ◆ upd_passive_fiber_strain_at_one_norm_force()

 double& OpenSim::DeGrooteFregly2016Muscle::upd_passive_fiber_strain_at_one_norm_force ( )
inline

Get a writable reference to the passive_fiber_strain_at_one_norm_force property.

## ◆ upd_tendon_compliance_dynamics_mode()

 std::string& OpenSim::DeGrooteFregly2016Muscle::upd_tendon_compliance_dynamics_mode ( )
inline

Get a writable reference to the tendon_compliance_dynamics_mode property.

## ◆ upd_tendon_strain_at_one_norm_force()

 double& OpenSim::DeGrooteFregly2016Muscle::upd_tendon_strain_at_one_norm_force ( )
inline

Get a writable reference to the tendon_strain_at_one_norm_force property.

## ◆ activation_time_constant

 double OpenSim::DeGrooteFregly2016Muscle::activation_time_constant

"Smaller value means activation can increase more rapidly. " "Default: 0.015 seconds."

This property appears in XML files under the tag <activation_time_constant>. This property was generated with the OpenSim_DECLARE_PROPERTY macro; see Property to learn about the property system.

get_activation_time_constant(), upd_activation_time_constant(), set_activation_time_constant()

## ◆ active_force_width_scale

 double OpenSim::DeGrooteFregly2016Muscle::active_force_width_scale

"Scale factor for the width of the active force-length curve. " "Larger values make the curve wider. Default: 1.0."

This property appears in XML files under the tag <active_force_width_scale>. This property was generated with the OpenSim_DECLARE_PROPERTY macro; see Property to learn about the property system.

get_active_force_width_scale(), upd_active_force_width_scale(), set_active_force_width_scale()

## ◆ deactivation_time_constant

 double OpenSim::DeGrooteFregly2016Muscle::deactivation_time_constant

"Smaller value means activation can decrease more rapidly. " "Default: 0.060 seconds."

This property appears in XML files under the tag <deactivation_time_constant>. This property was generated with the OpenSim_DECLARE_PROPERTY macro; see Property to learn about the property system.

get_deactivation_time_constant(), upd_deactivation_time_constant(), set_deactivation_time_constant()

## ◆ default_activation

 double OpenSim::DeGrooteFregly2016Muscle::default_activation

"Value of activation in the default state returned by " "initSystem(). Default: 0.5."

This property appears in XML files under the tag <default_activation>. This property was generated with the OpenSim_DECLARE_PROPERTY macro; see Property to learn about the property system.

get_default_activation(), upd_default_activation(), set_default_activation()

## ◆ default_normalized_tendon_force

 double OpenSim::DeGrooteFregly2016Muscle::default_normalized_tendon_force

"Value of normalized tendon force in the default state returned by " "initSystem(). Default: 0.5."

This property appears in XML files under the tag <default_normalized_tendon_force>. This property was generated with the OpenSim_DECLARE_PROPERTY macro; see Property to learn about the property system.

get_default_normalized_tendon_force(), upd_default_normalized_tendon_force(), set_default_normalized_tendon_force()

## ◆ fiber_damping

 double OpenSim::DeGrooteFregly2016Muscle::fiber_damping

"Use this property to define the linear damping force that is " "added to the total muscle fiber force. It is computed by " "multiplying this damping parameter by the normalized fiber " "velocity and the max isometric force. Default: 0."

This property appears in XML files under the tag <fiber_damping>. This property was generated with the OpenSim_DECLARE_PROPERTY macro; see Property to learn about the property system.

get_fiber_damping(), upd_fiber_damping(), set_fiber_damping()

## ◆ ignore_passive_fiber_force

 bool OpenSim::DeGrooteFregly2016Muscle::ignore_passive_fiber_force

"Make the passive fiber force 0. Default: false."

This property appears in XML files under the tag <ignore_passive_fiber_force>. This property was generated with the OpenSim_DECLARE_PROPERTY macro; see Property to learn about the property system.

get_ignore_passive_fiber_force(), upd_ignore_passive_fiber_force(), set_ignore_passive_fiber_force()

## ◆ implicitenabled_normalized_tendon_force

 bool OpenSim::DeGrooteFregly2016Muscle::implicitenabled_normalized_tendon_force

Provides the value of getImplicitEnabledNormalizedTendonForce() and is available at stage SimTK::Stage::Model .

This output was generated with the OpenSim_DECLARE_OUTPUT macro.

## ◆ implicitresidual_normalized_tendon_force

 double OpenSim::DeGrooteFregly2016Muscle::implicitresidual_normalized_tendon_force

Provides the value of getImplicitResidualNormalizedTendonForce() and is available at stage SimTK::Stage::Dynamics .

This output was generated with the OpenSim_DECLARE_OUTPUT macro.

## ◆ passive_fiber_damping_force

 double OpenSim::DeGrooteFregly2016Muscle::passive_fiber_damping_force

Provides the value of getPassiveFiberDampingForce() and is available at stage SimTK::Stage::Dynamics .

This output was generated with the OpenSim_DECLARE_OUTPUT macro.

## ◆ passive_fiber_damping_force_along_tendon

 double OpenSim::DeGrooteFregly2016Muscle::passive_fiber_damping_force_along_tendon

Provides the value of getPassiveFiberDampingForceAlongTendon() and is available at stage SimTK::Stage::Dynamics .

This output was generated with the OpenSim_DECLARE_OUTPUT macro.

## ◆ passive_fiber_elastic_force

 double OpenSim::DeGrooteFregly2016Muscle::passive_fiber_elastic_force

Provides the value of getPassiveFiberElasticForce() and is available at stage SimTK::Stage::Dynamics .

This output was generated with the OpenSim_DECLARE_OUTPUT macro.

## ◆ passive_fiber_elastic_force_along_tendon

 double OpenSim::DeGrooteFregly2016Muscle::passive_fiber_elastic_force_along_tendon

Provides the value of getPassiveFiberElasticForceAlongTendon() and is available at stage SimTK::Stage::Dynamics .

This output was generated with the OpenSim_DECLARE_OUTPUT macro.

## ◆ passive_fiber_strain_at_one_norm_force

 double OpenSim::DeGrooteFregly2016Muscle::passive_fiber_strain_at_one_norm_force

"Fiber strain when the passive fiber force is 1 normalized force. " "Default: 0.6."

This property appears in XML files under the tag <passive_fiber_strain_at_one_norm_force>. This property was generated with the OpenSim_DECLARE_PROPERTY macro; see Property to learn about the property system.

get_passive_fiber_strain_at_one_norm_force(), upd_passive_fiber_strain_at_one_norm_force(), set_passive_fiber_strain_at_one_norm_force()

## ◆ statebounds_normalized_tendon_force

 SimTK::Vec2 OpenSim::DeGrooteFregly2016Muscle::statebounds_normalized_tendon_force

Provides the value of getBoundsNormalizedTendonForce() and is available at stage SimTK::Stage::Model .

This output was generated with the OpenSim_DECLARE_OUTPUT macro.

## ◆ tendon_compliance_dynamics_mode

 std::string OpenSim::DeGrooteFregly2016Muscle::tendon_compliance_dynamics_mode

"The dynamics method used to enforce tendon compliance dynamics. " "Options: 'explicit' or 'implicit'. Default: 'explicit'. "

This property appears in XML files under the tag <tendon_compliance_dynamics_mode>. This property was generated with the OpenSim_DECLARE_PROPERTY macro; see Property to learn about the property system.

get_tendon_compliance_dynamics_mode(), upd_tendon_compliance_dynamics_mode(), set_tendon_compliance_dynamics_mode()

## ◆ tendon_strain_at_one_norm_force

 double OpenSim::DeGrooteFregly2016Muscle::tendon_strain_at_one_norm_force

"Tendon strain at a tension of 1 normalized force. " "Default: 0.049."

This property appears in XML files under the tag <tendon_strain_at_one_norm_force>. This property was generated with the OpenSim_DECLARE_PROPERTY macro; see Property to learn about the property system.