OpenSim::Millard2012EquilibriumMuscle Class Reference

This class implements a configurable equilibrium muscle model, as described in Millard et al. (2013). More...

Inheritance diagram for OpenSim::Millard2012EquilibriumMuscle:

OpenSim Properties, Sockets, Outputs, Inputs
Properties (single-value)
double	fiber_damping
	"The linear damping of the fiber." More...
double	default_activation
	"Assumed initial activation level if none is assigned." More...
double	default_fiber_length
	"Assumed initial fiber length if none is assigned." More...
double	activation_time_constant
	"Activation time constant (in seconds)." More...
double	deactivation_time_constant
	"Deactivation time constant (in seconds)." More...
double	minimum_activation
	"Activation lower bound." More...
double	maximum_pennation_angle
	"Maximum pennation angle (in radians)." More...
Properties (unnamed)
ActiveForceLengthCurve	ActiveForceLengthCurve
	"Active-force-length curve." More...
ForceVelocityCurve	ForceVelocityCurve
	"Force-velocity curve." More...
FiberForceLengthCurve	FiberForceLengthCurve
	"Passive-force-length curve." More...
TendonForceLengthCurve	TendonForceLengthCurve
	"Tendon-force-length curve." 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...
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
	Millard2012EquilibriumMuscle ()
	Default constructor. More...
	Millard2012EquilibriumMuscle (const std::string &aName, double aMaxIsometricForce, double aOptimalFiberLength, double aTendonSlackLength, double aPennationAngle)
	Constructs a functional muscle using default curves and activation model parameters. More...
bool	getUseFiberDamping () const
double	getFiberDamping () const
double	getDefaultActivation () const
double	getDefaultFiberLength () const
double	getActivationTimeConstant () const
double	getDeactivationTimeConstant () const
double	getMinimumActivation () const
const ActiveForceLengthCurve &	getActiveForceLengthCurve () const
const ForceVelocityCurve &	getForceVelocityCurve () const
const FiberForceLengthCurve &	getFiberForceLengthCurve () const
const TendonForceLengthCurve &	getTendonForceLengthCurve () const
const MuscleFixedWidthPennationModel &	getPennationModel () const
const MuscleFirstOrderActivationDynamicModel &	getActivationModel () const
double	getMinimumFiberLength () const
double	getMinimumFiberLengthAlongTendon () const
double	getTendonForceMultiplier (SimTK::State &s) const
double	getFiberStiffnessAlongTendon (const SimTK::State &s) const
double	getFiberVelocity (const SimTK::State &s) const
double	getActivationDerivative (const SimTK::State &s) const
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...
void	setMuscleConfiguration (bool ignoreTendonCompliance, bool ignoreActivationDynamics, double dampingCoefficient)
void	setFiberDamping (double dampingCoefficient)
void	setDefaultActivation (double activation)
void	setActivation (SimTK::State &s, double activation) const override
void	setDefaultFiberLength (double fiberLength)
void	setActivationTimeConstant (double activationTimeConstant)
void	setDeactivationTimeConstant (double deactivationTimeConstant)
void	setMinimumActivation (double minimumActivation)
void	setActiveForceLengthCurve (ActiveForceLengthCurve &aActiveForceLengthCurve)
void	setForceVelocityCurve (ForceVelocityCurve &aForceVelocityCurve)
void	setFiberForceLengthCurve (FiberForceLengthCurve &aFiberForceLengthCurve)
void	setTendonForceLengthCurve (TendonForceLengthCurve &aTendonForceLengthCurve)
void	setFiberLength (SimTK::State &s, double fiberLength) const
double	computeActuation (const SimTK::State &s) const override final
void	computeInitialFiberEquilibrium (SimTK::State &s) const override
	Computes the fiber length such that the fiber and tendon are developing the same force, distributing the velocity of the entire musculotendon actuator between the fiber and tendon according to their relative stiffnesses. More...
void	computeFiberEquilibrium (SimTK::State &s, bool solveForVelocity=false) const
	Computes the fiber length such that the fiber and tendon are developing the same force, either assuming muscle-tendon velocity as provided by the state or zero as designated by the useZeroVelocity flag. More...
void	extendPostScale (const SimTK::State &s, const ScaleSet &scaleSet) override
	Adjust the properties of the muscle after the model has been scaled. More...
Property-related functions
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 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_fiber_length () const
	Get the value of the default_fiber_length property. More...
double &	upd_default_fiber_length ()
	Get a writable reference to the default_fiber_length property. More...
void	set_default_fiber_length (const double &value)
	Set the value of the default_fiber_length property. More...
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_minimum_activation () const
	Get the value of the minimum_activation property. More...
double &	upd_minimum_activation ()
	Get a writable reference to the minimum_activation property. More...
void	set_minimum_activation (const double &value)
	Set the value of the minimum_activation property. More...
const double &	get_maximum_pennation_angle () const
	Get the value of the maximum_pennation_angle property. More...
double &	upd_maximum_pennation_angle ()
	Get a writable reference to the maximum_pennation_angle property. More...
void	set_maximum_pennation_angle (const double &value)
	Set the value of the maximum_pennation_angle property. More...
const ActiveForceLengthCurve &	get_ActiveForceLengthCurve () const
	Get the value of the ActiveForceLengthCurve property. More...
ActiveForceLengthCurve &	upd_ActiveForceLengthCurve ()
	Get a writable reference to the ActiveForceLengthCurve property. More...
void	set_ActiveForceLengthCurve (const ActiveForceLengthCurve &value)
	Set the value of the ActiveForceLengthCurve property. More...
const ForceVelocityCurve &	get_ForceVelocityCurve () const
	Get the value of the ForceVelocityCurve property. More...
ForceVelocityCurve &	upd_ForceVelocityCurve ()
	Get a writable reference to the ForceVelocityCurve property. More...
void	set_ForceVelocityCurve (const ForceVelocityCurve &value)
	Set the value of the ForceVelocityCurve property. More...
const FiberForceLengthCurve &	get_FiberForceLengthCurve () const
	Get the value of the FiberForceLengthCurve property. More...
FiberForceLengthCurve &	upd_FiberForceLengthCurve ()
	Get a writable reference to the FiberForceLengthCurve property. More...
void	set_FiberForceLengthCurve (const FiberForceLengthCurve &value)
	Set the value of the FiberForceLengthCurve property. More...
const TendonForceLengthCurve &	get_TendonForceLengthCurve () const
	Get the value of the TendonForceLengthCurve property. More...
TendonForceLengthCurve &	upd_TendonForceLengthCurve ()
	Get a writable reference to the TendonForceLengthCurve property. More...
void	set_TendonForceLengthCurve (const TendonForceLengthCurve &value)
	Set the value of the TendonForceLengthCurve property. More...
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
virtual double	getActivation (const SimTK::State &s) const
	get the activation level of the muscle, which modulates the active force of the muscle and has a normalized (0 to 1) value Note: method remains virtual to permit override by deprecated muscles. More...
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 ()
GeometryPath &	updGeometryPath ()
const GeometryPath &	getGeometryPath () 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 GeometryPath &	get_GeometryPath () const
	Get the value of the GeometryPath property. More...
GeometryPath &	upd_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...
PathActuator *	clone () 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 Model &	getModel () const
	Get a const reference to the Model this component is part of. More...
Model &	updModel ()
	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...
Component &	operator= (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...
void	addComponent (Component *subcomponent)
	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 Component &	getComponent (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)
Component &	updComponent (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 StateVariable *	traverseToStateVariable (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...
void	addToSystem (SimTK::MultibodySystem &system) const
	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 Object &	getConnectee (const std::string &name) const
	Get the connectee as an Object. More...
const AbstractSocket &	getSocket (const std::string &name) const
	Get an AbstractSocket for the given socket name. More...
AbstractSocket &	updSocket (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 AbstractInput &	getInput (const std::string &name) const
	Get an Input provided by this Component by name. More...
AbstractInput &	updInput (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 AbstractOutput &	getOutput (const std::string &name) const
	Get the Output provided by this Component by name. More...
AbstractOutput &	updOutput (const std::string &name)
	Get a writable reference to an Output provided by this Component by name. More...
SimTK::IteratorRange< OutputConstIterator >	getOutputs () 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 Component &	getOwner () const
	Access the owner of this Component. More...
bool	hasOwner () const
	(For advanced users) Check if this Component has an owner. More...
const Component &	getRoot () 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...
Object &	operator= (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 AbstractProperty &	getPropertyByIndex (int propertyIndex) const
	Get a const reference to a property by its index number, returned as an AbstractProperty. More...
AbstractProperty &	updPropertyByIndex (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 AbstractProperty &	getPropertyByName (const std::string &name) const
	Get a const reference to a property by its name, returned as an AbstractProperty. More...
AbstractProperty &	updPropertyByName (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...
PropertySet &	getPropertySet ()
	OBSOLETE: Get a reference to the PropertySet maintained by the Object. More...
const PropertySet &	getPropertySet () const

Public Types
typedef Millard2012EquilibriumMuscle	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
double	getStateVariableDeriv (const SimTK::State &s, const std::string &aStateName) const
	Gets the derivative of an actuator state by index. More...
void	setStateVariableDeriv (const SimTK::State &s, const std::string &aStateName, double aValue) const
	Sets the derivative of an actuator state specified by name. More...
void	calcMuscleLengthInfo (const SimTK::State &s, MuscleLengthInfo &mli) const override
	Calculate the position-related values associated with the muscle state (fiber and tendon lengths, normalized lengths, pennation angle, etc.). More...
void	calcFiberVelocityInfo (const SimTK::State &s, FiberVelocityInfo &fvi) const override
	Calculate the velocity-related values associated with the muscle state (fiber and tendon velocities, normalized velocities, pennation angular velocity, etc.). More...
void	calcMuscleDynamicsInfo (const SimTK::State &s, MuscleDynamicsInfo &mdi) const override
	Calculate the dynamics-related values associated with the muscle state (from the active- and passive-force-length curves, the force-velocity curve, and the tendon-force-length curve). More...
void	calcMusclePotentialEnergyInfo (const SimTK::State &s, MusclePotentialEnergyInfo &mpei) const override
	Calculate the potential energy values associated with the muscle. More...
void	extendConnectToModel (Model &model) override
	Sets up the ModelComponent from the model, if necessary. More...
void	extendAddToSystem (SimTK::MultibodySystem &system) const override
	Creates the ModelComponent so that it can be used in simulation. More...
void	extendInitStateFromProperties (SimTK::State &s) const override
	Initializes the state of the ModelComponent. More...
void	extendSetPropertiesFromState (const SimTK::State &s) override
	Sets the default state for the ModelComponent. More...
void	computeStateVariableDerivatives (const SimTK::State &s) const override
	Computes state variable derivatives. More...
Protected Member Functions inherited from OpenSim::Muscle
const MuscleLengthInfo &	getMuscleLengthInfo (const SimTK::State &s) const
	Developer Access to intermediate values calculate by the muscle model. More...
MuscleLengthInfo &	updMuscleLengthInfo (const SimTK::State &s) const
const FiberVelocityInfo &	getFiberVelocityInfo (const SimTK::State &s) const
FiberVelocityInfo &	updFiberVelocityInfo (const SimTK::State &s) const
const MuscleDynamicsInfo &	getMuscleDynamicsInfo (const SimTK::State &s) const
MuscleDynamicsInfo &	updMuscleDynamicsInfo (const SimTK::State &s) const
const MusclePotentialEnergyInfo &	getMusclePotentialEnergyInfo (const SimTK::State &s) const
MusclePotentialEnergyInfo &	updMusclePotentialEnergyInfo (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...
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)
void	adoptSubcomponent (Component *subcomponent)
	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...
size_t	getNumAdoptedSubcomponents () const
	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 Component &	get_components (int i) const
	Get the value of the i-th element of the components property. More...
Component &	upd_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...
virtual void	extendAddComponent (Component *subcomponent)
	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...
void	addStateVariable (Component::StateVariable *stateVariable) const
	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 XMLDocument *	getDocument () const
	Get a const pointer to the document (if any) associated with this object. More...
XMLDocument *	updDocument ()
	Get a writable pointer to the document (if any) associated with this object. More...

Auto-generated functions
static Millard2012EquilibriumMuscle *	safeDownCast (OpenSim::Object *obj)
	For use in MATLAB and Python to access the concrete class. More...
static const std::string &	getClassName ()
	This returns "Millard2012EquilibriumMuscle". More...
void	assign (Object &aObject) override
	This allows copy assignment in the Java GUI. More...
Millard2012EquilibriumMuscle *	clone () 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...

Additional Inherited Members
Static Public Member Functions inherited from OpenSim::Muscle
static Muscle *	safeDownCast (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 PathActuator *	safeDownCast (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 ScalarActuator *	safeDownCast (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 Actuator *	safeDownCast (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 Force *	safeDownCast (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 ModelComponent *	safeDownCast (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 Component *	safeDownCast (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 Object *	getDefaultInstanceOfType (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 Object *	newInstanceOfType (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 Object *	makeObjectFromFile (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 Object *	SafeCopy (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...
Related Functions inherited from OpenSim::Object
#define	OpenSim_DECLARE_CONCRETE_OBJECT(ConcreteClass, SuperClass)
	Macro to be included as the first line of the class declaration for any non-templatized, concrete class that derives from OpenSim::Object. More...
#define	OpenSim_DECLARE_ABSTRACT_OBJECT(ConcreteClass, SuperClass)
	Macro to be included as the first line of the class declaration for any still-abstract class that derives from OpenSim::Object. More...
#define	OpenSim_DECLARE_CONCRETE_OBJECT_T(ConcreteClass, TArg, SuperClass)
	Macro to be included as the first line of the class declaration for any templatized, concrete class that derives from OpenSim::Object, like Set<T>. More...
#define	OpenSim_DECLARE_ABSTRACT_OBJECT_T(ConcreteClass, TArg, SuperClass)
	Macro to be included as the first line of the class declaration for any templatized, still-abstract class that derives from OpenSim::Object. More...

Detailed Description

This class implements a configurable equilibrium muscle model, as described in Millard et al. (2013).

An equilibrium model assumes that the forces generated by the fiber and tendon are equal:

\[ f_{ISO}\Big(\mathbf{a}(t) \mathbf{f}_L(\hat{l}_{CE}) \mathbf{f}_V(\hat{v}_{CE}) + \mathbf{f}_{PE}(\hat{l}_{CE}) + \beta \hat{v}_{CE}\Big) \cos \phi - f_{ISO}\mathbf{f}_{SE}(\hat{l}_{T}) = 0 \]

This model can be simulated in several configurations by adjusting three flags:

• ignore_tendon_compliance: set to true to make the tendon rigid. This assumption is usually reasonable for short tendons, and can result in a performance improvement by eliminating high-frequency dynamics and removing the fiber length from the state vector.

• ignore_activation_dynamics: set to true to use the excitation input as the activation signal. This results in faster simulations by reducing the size of the state vector.

• fiber_damping: set to a value greater than 0.001 to include fiber damping in the model. The addition of damping reduces simulation time while allowing the muscle model to be more physiological (it can have an activation of zero, its active-force-length curve can go to zero, and its force-velocity curve can be asymptotic).

Elastic Tendon, No Fiber Damping

The most typical configuration used in the literature is to simulate a muscle with an elastic tendon, full fiber dynamics, and activation dynamics. The resulting formulation suffers from three singularities: \(\mathbf{a}(t) \rightarrow 0\), \(\phi \rightarrow 90^\circ\), and \( \mathbf{f}_L(\hat{l}_{CE}) \rightarrow 0 \). These situations are all handled in this model to ensure that it does not produce singularities and does not result in intolerably long simulation times.

Numerical singularities arise from the manner in which the equilibrium equation is rearranged to yield an ordinary differential equation (ODE). The above equation is rearranged to isolate \( \mathbf{f}_V(\hat{v}_{CE}) \). We then invert to solve for \( \hat{v}_{CE} \), which is then numerically integrated during a simulation:

\[ \hat{v}_{CE} = \mathbf{f}_V ^{-1} \Big( \frac{ ( \mathbf{f}_{SE}(\hat{l}_{T}) ) / \cos \phi - \mathbf{f}_{PE}(\hat{l}_{CE}) } { \mathbf{a}(t) \mathbf{f}_L(\hat{l}_{CE})} \Big) \]

The above equation becomes numerically stiff when terms in the denominator approach zero (when \(\mathbf{a}(t) \rightarrow 0\), \(\phi \rightarrow 90^\circ\), or \( \mathbf{f}_L(\hat{l}_{CE}) \rightarrow 0 \)) or, additionally, when the slope of \(\mathbf{f}_V ^{-1}\) is steep (which occurs at fiber velocities close to the maximum concentric and maximum eccentric fiber velocities).

Singularities can be managed by ensuring that the muscle model is always activated ( \(\mathbf{a}(t) > 0\)), the fiber will stop contracting when a pennation angle of 90 degrees is approached ( \(\phi < 90^\circ\)), and the fiber will also stop contracting as its length approaches a lower bound ( \( \hat{l}_{CE} > lowerbound\)), which is typically around half the fiber's resting length (to ensure \( \mathbf{f}_L(\hat{l}_{CE}) > 0 \)). The fiber is prevented from reaching unphysiological lengths or its maximum pennation angle using a unilateral constraint. Additionally, the force-velocity curve is modified so that it is invertible.

When an elastic tendon without fiber damping is selected, the minimum active-force-length value is set to 0.1, the minimum permissible activation is set to 0.01, and the maximum permissible pennation angle is set to acos(0.1) or 84.3 degrees. This is done as a convenience for the user to prevent the model from taking an unreasonable amount of time to simulate.

(Rigid Tendon) or (Elastic Tendon with Fiber Damping)

Neither of these formulations has any singularities. The lower bound of the active-force-length curve can be zero (min( \( \mathbf{f}_L(\hat{l}_{CE})) = 0 \)), activation can be zero (i.e., the muscle can be turned off completely), and the force-velocity curve need not be invertible.

The rigid tendon formulation removes the singularities by ignoring the elasticity of the tendon. This assumption is reasonable for many muscles, but it is up to the user to determine whether this assumption is valid.

The formulation that uses an elastic tendon with fiber damping removes singularities by solving the equilibrium equation with Newton's method. This is possible because the partial derivative of the equilibrium equation with respect to fiber velocity is always positive if \( \beta > 0\) and, thus, Newton's method can find a solution to the equilibrium equation.

When either of these singularity-free formulations is selected, the minimum active-force-length value and the minimum permissible activation are set to zero. This is done as a convenience for the user, as these changes make the results of the model more realistic yet incur no performance penalty. The maximum pennation angle is left as acos(0.1) or 84.3 degrees, as allowing higher pennation angles results in an increasingly stiff fiber velocity state as pennation angle increases.

Usage

This object should be updated through the set methods provided.

Example

double maxIsometricForce  = 5000;   //N
double optimalFiberLength = 0.025;  //m
double tendonSlackLength  = 0.25;   //m
double pennationAngle     = 0.5;    //rad

bool ignoreTendonCompliance   = false;
bool ignoreActivationDynamics = false;
double dampingCoefficient     = 0.001;

Millard2012EquilibriumMuscle myMuscle("myMuscle",
                                      maxIsometricForce,
                                      optimalFiberLength,
                                      tendonSlackLength,
                                      pennationAngle);

myMuscle.setMuscleConfiguration(ignoreTendonCompliance,
                                ignoreActivationDynamics,
                                dampingCoefficient);

Please refer to the doxygen for more information on the properties that are objects themselves (MuscleFixedWidthPennationModel, ActiveForceLengthCurve, FiberForceLengthCurve, TendonForceLengthCurve, and ForceVelocityInverseCurve).

Reference

Millard, M., Uchida, T., Seth, A., Delp, S.L. (2013) Flexing computational muscle: modeling and simulation of musculotendon dynamics. ASME Journal of Biomechanical Engineering 135(2):021005. http://dx.doi.org/10.1115/1.4023390.

Author

Matt Millard

Tom Uchida

Ajay Seth

Member Typedef Documentation

Self

typedef Millard2012EquilibriumMuscle OpenSim::Millard2012EquilibriumMuscle::Self

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

This is generated by the OpenSim_DECLARE_*_OBJECT macros.

Super

typedef Muscle OpenSim::Millard2012EquilibriumMuscle::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.

Constructor & Destructor Documentation

Millard2012EquilibriumMuscle() [1/2]

OpenSim::Millard2012EquilibriumMuscle::Millard2012EquilibriumMuscle

(

)

Default constructor.

Produces a non-functional empty muscle.

Millard2012EquilibriumMuscle() [2/2]

OpenSim::Millard2012EquilibriumMuscle::Millard2012EquilibriumMuscle	(	const std::string &	aName,
		double	aMaxIsometricForce,
		double	aOptimalFiberLength,
		double	aTendonSlackLength,
		double	aPennationAngle
	)

Constructs a functional muscle using default curves and activation model parameters.

The tendon is assumed to be elastic, full fiber dynamics are solved, and activation dynamics are included.

Parameters

aName	The name of the muscle.
aMaxIsometricForce	The force generated by the muscle when fully activated at its optimal resting length with a contraction velocity of zero.
aOptimalFiberLength	The optimal length of the muscle fiber.
aTendonSlackLength	The resting length of the tendon.
aPennationAngle	The angle of the fiber (in radians) relative to the tendon when the fiber is at its optimal resting length.

Member Function Documentation

assign()

void OpenSim::Millard2012EquilibriumMuscle::assign ( Object &  aObject )

inlineoverride

This allows copy assignment in the Java GUI.

Exceptions

Exception

if the argument is not of type Millard2012EquilibriumMuscle.

calcFiberVelocityInfo()

void OpenSim::Millard2012EquilibriumMuscle::calcFiberVelocityInfo ( const SimTK::State &  s, FiberVelocityInfo &  fvi  ) const

overrideprotectedvirtual

Calculate the velocity-related values associated with the muscle state (fiber and tendon velocities, normalized velocities, pennation angular velocity, etc.).

Reimplemented from OpenSim::Muscle.

calcMuscleDynamicsInfo()

void OpenSim::Millard2012EquilibriumMuscle::calcMuscleDynamicsInfo ( const SimTK::State &  s, MuscleDynamicsInfo &  mdi  ) const

overrideprotectedvirtual

Calculate the dynamics-related values associated with the muscle state (from the active- and passive-force-length curves, the force-velocity curve, and the tendon-force-length curve).

The last entry is a SimTK::Vector containing the passive conservative (elastic) fiber force and the passive non-conservative (damping) fiber force.

Reimplemented from OpenSim::Muscle.

calcMuscleLengthInfo()

void OpenSim::Millard2012EquilibriumMuscle::calcMuscleLengthInfo ( const SimTK::State &  s, MuscleLengthInfo &  mli  ) const

overrideprotectedvirtual

Calculate the position-related values associated with the muscle state (fiber and tendon lengths, normalized lengths, pennation angle, etc.).

Reimplemented from OpenSim::Muscle.

calcMusclePotentialEnergyInfo()

void OpenSim::Millard2012EquilibriumMuscle::calcMusclePotentialEnergyInfo ( const SimTK::State &  s, MusclePotentialEnergyInfo &  mpei  ) const

overrideprotectedvirtual

Calculate the potential energy values associated with the muscle.

Reimplemented from OpenSim::Muscle.

clone()

Millard2012EquilibriumMuscle* OpenSim::Millard2012EquilibriumMuscle::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::Millard2012EquilibriumMuscle::computeActuation ( const SimTK::State &  s ) const

finaloverridevirtual

Parameters

[in]

s

The state of the system.

Returns

The tensile force the muscle is generating (N).

Implements OpenSim::Muscle.

computeFiberEquilibrium()

void OpenSim::Millard2012EquilibriumMuscle::computeFiberEquilibrium	(	SimTK::State &	s,
		bool	solveForVelocity = false
	)		const

Computes the fiber length such that the fiber and tendon are developing the same force, either assuming muscle-tendon velocity as provided by the state or zero as designated by the useZeroVelocity flag.

Parameters

[in,out]	s	The state of the system.
	solveForVelocity	Flag indicating to solve for fiber velocity, which by default is false (zero fiber-velocity)

Exceptions

MuscleCannotEquilibrate

computeInitialFiberEquilibrium()

void OpenSim::Millard2012EquilibriumMuscle::computeInitialFiberEquilibrium ( SimTK::State &  s ) const

inlineoverridevirtual

Computes the fiber length such that the fiber and tendon are developing the same force, distributing the velocity of the entire musculotendon actuator between the fiber and tendon according to their relative stiffnesses.

Parameters

[in,out]

s

The state of the system.

Exceptions

MuscleCannotEquilibrate

Implements OpenSim::Muscle.

computeStateVariableDerivatives()

void OpenSim::Millard2012EquilibriumMuscle::computeStateVariableDerivatives ( const SimTK::State &  s ) const

overrideprotectedvirtual

Computes state variable derivatives.

Reimplemented from OpenSim::Component.

extendAddToSystem()

void OpenSim::Millard2012EquilibriumMuscle::extendAddToSystem ( SimTK::MultibodySystem &  system ) const

overrideprotectedvirtual

Creates the ModelComponent so that it can be used in simulation.

Reimplemented from OpenSim::Component.

extendConnectToModel()

void OpenSim::Millard2012EquilibriumMuscle::extendConnectToModel ( Model &  model )

overrideprotectedvirtual

Sets up the ModelComponent from the model, if necessary.

Reimplemented from OpenSim::ModelComponent.

extendInitStateFromProperties()

void OpenSim::Millard2012EquilibriumMuscle::extendInitStateFromProperties ( SimTK::State &  s ) const

overrideprotectedvirtual

Initializes the state of the ModelComponent.

Reimplemented from OpenSim::Component.

extendPostScale()

void OpenSim::Millard2012EquilibriumMuscle::extendPostScale ( const SimTK::State &  s, const ScaleSet &  scaleSet  )

overridevirtual

Adjust the properties of the muscle after the model has been scaled.

The optimal fiber length and tendon slack length are each multiplied by the ratio of the current path length and the path length before scaling.

Reimplemented from OpenSim::ModelComponent.

extendSetPropertiesFromState()

void OpenSim::Millard2012EquilibriumMuscle::extendSetPropertiesFromState ( const SimTK::State &  s )

overrideprotectedvirtual

Sets the default state for the ModelComponent.

Reimplemented from OpenSim::Component.

get_activation_time_constant()

const double& OpenSim::Millard2012EquilibriumMuscle::get_activation_time_constant ( ) const

inline

Get the value of the activation_time_constant property.

get_ActiveForceLengthCurve()

const ActiveForceLengthCurve& OpenSim::Millard2012EquilibriumMuscle::get_ActiveForceLengthCurve ( ) const

inline

Get the value of the ActiveForceLengthCurve property.

get_deactivation_time_constant()

const double& OpenSim::Millard2012EquilibriumMuscle::get_deactivation_time_constant ( ) const

inline

Get the value of the deactivation_time_constant property.

get_default_activation()

const double& OpenSim::Millard2012EquilibriumMuscle::get_default_activation ( ) const

inline

Get the value of the default_activation property.

get_default_fiber_length()

const double& OpenSim::Millard2012EquilibriumMuscle::get_default_fiber_length ( ) const

inline

Get the value of the default_fiber_length property.

get_fiber_damping()

const double& OpenSim::Millard2012EquilibriumMuscle::get_fiber_damping ( ) const

inline

Get the value of the fiber_damping property.

get_FiberForceLengthCurve()

const FiberForceLengthCurve& OpenSim::Millard2012EquilibriumMuscle::get_FiberForceLengthCurve ( ) const

inline

Get the value of the FiberForceLengthCurve property.

get_ForceVelocityCurve()

const ForceVelocityCurve& OpenSim::Millard2012EquilibriumMuscle::get_ForceVelocityCurve ( ) const

inline

Get the value of the ForceVelocityCurve property.

get_maximum_pennation_angle()

const double& OpenSim::Millard2012EquilibriumMuscle::get_maximum_pennation_angle ( ) const

inline

Get the value of the maximum_pennation_angle property.

get_minimum_activation()

const double& OpenSim::Millard2012EquilibriumMuscle::get_minimum_activation ( ) const

inline

Get the value of the minimum_activation property.

get_TendonForceLengthCurve()

const TendonForceLengthCurve& OpenSim::Millard2012EquilibriumMuscle::get_TendonForceLengthCurve ( ) const

inline

Get the value of the TendonForceLengthCurve property.

getActivationDerivative()

double OpenSim::Millard2012EquilibriumMuscle::getActivationDerivative

(

const SimTK::State &

s

)

const

Parameters

s	The state of the system.

Returns

The time derivative of activation.

getActivationModel()

const MuscleFirstOrderActivationDynamicModel& OpenSim::Millard2012EquilibriumMuscle::getActivationModel

(

)

const

Returns

The MuscleFirstOrderActivationDynamicModel owned by this model.

getActivationTimeConstant()

double OpenSim::Millard2012EquilibriumMuscle::getActivationTimeConstant

(

)

const

Returns

The activation time constant (in seconds).

getActiveForceLengthCurve()

const ActiveForceLengthCurve& OpenSim::Millard2012EquilibriumMuscle::getActiveForceLengthCurve

(

)

const

Returns

The ActiveForceLengthCurve used by this model.

getClassName()

static const std::string& OpenSim::Millard2012EquilibriumMuscle::getClassName ( )

inlinestatic

This returns "Millard2012EquilibriumMuscle".

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::Millard2012EquilibriumMuscle::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.

See also

getClassName()

Implements OpenSim::Muscle.

getDeactivationTimeConstant()

double OpenSim::Millard2012EquilibriumMuscle::getDeactivationTimeConstant

(

)

const

Returns

The deactivation time constant (in seconds).

getDefaultActivation()

double OpenSim::Millard2012EquilibriumMuscle::getDefaultActivation

(

)

const

Returns

The default activation level that is used as an initial condition if none is provided by the user.

getDefaultFiberLength()

double OpenSim::Millard2012EquilibriumMuscle::getDefaultFiberLength

(

)

const

Returns

The default fiber length that is used as an initial condition if none is provided by the user.

getFiberDamping()

double OpenSim::Millard2012EquilibriumMuscle::getFiberDamping

(

)

const

Returns

The fiber damping coefficient.

getFiberForceLengthCurve()

const FiberForceLengthCurve& OpenSim::Millard2012EquilibriumMuscle::getFiberForceLengthCurve

(

)

const

Returns

The FiberForceLengthCurve used by this model.

getFiberStiffnessAlongTendon()

double OpenSim::Millard2012EquilibriumMuscle::getFiberStiffnessAlongTendon

(

const SimTK::State &

s

)

const

Returns

The stiffness of the muscle fibers along the tendon (N/m).

getFiberVelocity()

double OpenSim::Millard2012EquilibriumMuscle::getFiberVelocity

(

const SimTK::State &

s

)

const

Parameters

s	The state of the system.

Returns

The velocity of the fiber (m/s).

getForceVelocityCurve()

const ForceVelocityCurve& OpenSim::Millard2012EquilibriumMuscle::getForceVelocityCurve

(

)

const

Returns

The ForceVelocityCurve used by this model.

getMinimumActivation()

double OpenSim::Millard2012EquilibriumMuscle::getMinimumActivation

(

)

const

Returns

The minimum activation level permitted by the muscle model. Note that this equilibrium model, like all equilibrium models, has a singularity when activation approaches 0, which means that a non-zero lower bound is required.

getMinimumFiberLength()

double OpenSim::Millard2012EquilibriumMuscle::getMinimumFiberLength

(

)

const

Returns

The minimum fiber length, which is the maximum of two values: the smallest fiber length allowed by the pennation model, and the minimum fiber length on the active-force-length curve. When the fiber reaches this length, it is constrained to this value until the fiber velocity becomes positive.

getMinimumFiberLengthAlongTendon()

double OpenSim::Millard2012EquilibriumMuscle::getMinimumFiberLengthAlongTendon

(

)

const

Returns

The minimum fiber length along the tendon, which is the maximum of two values: the smallest fiber length along the tendon permitted by the pennation model, and the minimum fiber length along the tendon on the active-force-length curve. When the fiber length reaches this value, it is constrained to this length along the tendon until the fiber velocity becomes positive.

getPassiveFiberDampingForce()

double OpenSim::Millard2012EquilibriumMuscle::getPassiveFiberDampingForce

(

const SimTK::State &

s

)

const

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

getPassiveFiberDampingForceAlongTendon()

double OpenSim::Millard2012EquilibriumMuscle::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::Millard2012EquilibriumMuscle::getPassiveFiberElasticForce

(

const SimTK::State &

s

)

const

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

getPassiveFiberElasticForceAlongTendon()

double OpenSim::Millard2012EquilibriumMuscle::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)

getPennationModel()

const MuscleFixedWidthPennationModel& OpenSim::Millard2012EquilibriumMuscle::getPennationModel

(

)

const

Returns

The MuscleFixedWidthPennationModel owned by this model.

getStateVariableDeriv()

double OpenSim::Millard2012EquilibriumMuscle::getStateVariableDeriv ( const SimTK::State &  s, const std::string &  aStateName  ) const

protected

Gets the derivative of an actuator state by index.

Parameters

s	The state.
aStateName	The name of the state to get.

Returns

The value of the state derivative.

getTendonForceLengthCurve()

const TendonForceLengthCurve& OpenSim::Millard2012EquilibriumMuscle::getTendonForceLengthCurve

(

)

const

Returns

The TendonForceLengthCurve used by this model.

getTendonForceMultiplier()

double OpenSim::Millard2012EquilibriumMuscle::getTendonForceMultiplier

(

SimTK::State &

s

)

const

Parameters

s	The state of the system.

Returns

The normalized force term associated with the tendon element, \(\mathbf{f}_{SE}(\hat{l}_{T})\), in the equilibrium equation.

getUseFiberDamping()

bool OpenSim::Millard2012EquilibriumMuscle::getUseFiberDamping

(

)

const

Returns

A boolean indicating whether fiber damping is being used.

safeDownCast()

static Millard2012EquilibriumMuscle* OpenSim::Millard2012EquilibriumMuscle::safeDownCast ( OpenSim::Object *  obj )

inlinestatic

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

Example: cObj = Millard2012EquilibriumMuscle.safeDownCast(obj). This is equivalent to dynamic_cast<Millard2012EquilibriumMuscle*>(obj) in C++.

set_activation_time_constant()

void OpenSim::Millard2012EquilibriumMuscle::set_activation_time_constant ( const double &  value )

inline

Set the value of the activation_time_constant property.

set_ActiveForceLengthCurve()

void OpenSim::Millard2012EquilibriumMuscle::set_ActiveForceLengthCurve ( const ActiveForceLengthCurve &  value )

inline

Set the value of the ActiveForceLengthCurve property.

set_deactivation_time_constant()

void OpenSim::Millard2012EquilibriumMuscle::set_deactivation_time_constant ( const double &  value )

inline

Set the value of the deactivation_time_constant property.

set_default_activation()

void OpenSim::Millard2012EquilibriumMuscle::set_default_activation ( const double &  value )

inline

Set the value of the default_activation property.

set_default_fiber_length()

void OpenSim::Millard2012EquilibriumMuscle::set_default_fiber_length ( const double &  value )

inline

Set the value of the default_fiber_length property.

set_fiber_damping()

void OpenSim::Millard2012EquilibriumMuscle::set_fiber_damping ( const double &  value )

inline

Set the value of the fiber_damping property.

set_FiberForceLengthCurve()

void OpenSim::Millard2012EquilibriumMuscle::set_FiberForceLengthCurve ( const FiberForceLengthCurve &  value )

inline

Set the value of the FiberForceLengthCurve property.

set_ForceVelocityCurve()

void OpenSim::Millard2012EquilibriumMuscle::set_ForceVelocityCurve ( const ForceVelocityCurve &  value )

inline

Set the value of the ForceVelocityCurve property.

set_maximum_pennation_angle()

void OpenSim::Millard2012EquilibriumMuscle::set_maximum_pennation_angle ( const double &  value )

inline

Set the value of the maximum_pennation_angle property.

set_minimum_activation()

void OpenSim::Millard2012EquilibriumMuscle::set_minimum_activation ( const double &  value )

inline

Set the value of the minimum_activation property.

set_TendonForceLengthCurve()

void OpenSim::Millard2012EquilibriumMuscle::set_TendonForceLengthCurve ( const TendonForceLengthCurve &  value )

inline

Set the value of the TendonForceLengthCurve property.

setActivation()

void OpenSim::Millard2012EquilibriumMuscle::setActivation ( SimTK::State &  s, double  activation  ) const

overridevirtual

Parameters

s	The state of the system.
activation	The desired activation level.

Implements OpenSim::Muscle.

setActivationTimeConstant()

void OpenSim::Millard2012EquilibriumMuscle::setActivationTimeConstant

(

double

activationTimeConstant

)

Parameters

activationTimeConstant

The activation time constant (in seconds).

setActiveForceLengthCurve()

void OpenSim::Millard2012EquilibriumMuscle::setActiveForceLengthCurve

(

ActiveForceLengthCurve &

aActiveForceLengthCurve

)

Parameters

aActiveForceLengthCurve

The ActiveForceLengthCurve used by the muscle model to scale active fiber force as a function of fiber length.

setDeactivationTimeConstant()

void OpenSim::Millard2012EquilibriumMuscle::setDeactivationTimeConstant

(

double

deactivationTimeConstant

)

Parameters

deactivationTimeConstant

The deactivation time constant (in seconds).

setDefaultActivation()

void OpenSim::Millard2012EquilibriumMuscle::setDefaultActivation

(

double

activation

)

Parameters

activation

The default activation level that is used to initialize the muscle.

setDefaultFiberLength()

void OpenSim::Millard2012EquilibriumMuscle::setDefaultFiberLength

(

double

fiberLength

)

Parameters

fiberLength

The default fiber length that is used to initialize the muscle.

setFiberDamping()

void OpenSim::Millard2012EquilibriumMuscle::setFiberDamping

(

double

dampingCoefficient

)

Parameters

dampingCoefficient

Define the fiber damping coefficient.

setFiberForceLengthCurve()

void OpenSim::Millard2012EquilibriumMuscle::setFiberForceLengthCurve

(

FiberForceLengthCurve &

aFiberForceLengthCurve

)

Parameters

aFiberForceLengthCurve

The FiberForceLengthCurve used by the muscle model to calculate the passive force the muscle fiber generates as a function of fiber length.

setFiberLength()

void OpenSim::Millard2012EquilibriumMuscle::setFiberLength	(	SimTK::State &	s,
		double	fiberLength
	)		const

Parameters

[out]	s	The state of the system.
	fiberLength	The desired fiber length (m).

setForceVelocityCurve()

void OpenSim::Millard2012EquilibriumMuscle::setForceVelocityCurve

(

ForceVelocityCurve &

aForceVelocityCurve

)

Parameters

aForceVelocityCurve

The ForceVelocityCurve used by the muscle model to calculate the derivative of fiber length.

setMinimumActivation()

void OpenSim::Millard2012EquilibriumMuscle::setMinimumActivation

(

double

minimumActivation

)

Parameters

minimumActivation

The minimum permissible activation level.

setMuscleConfiguration()

void OpenSim::Millard2012EquilibriumMuscle::setMuscleConfiguration	(	bool	ignoreTendonCompliance,
		bool	ignoreActivationDynamics,
		double	dampingCoefficient
	)

Parameters

ignoreTendonCompliance	Use a rigid (true) or elastic tendon.
ignoreActivationDynamics	Treat the excitation input as the activation signal (true) or use a first-order activation dynamic model.
dampingCoefficient	Specify the amount of damping to include in the model (must be either 0 or greater than 0.001).

setStateVariableDeriv()

void OpenSim::Millard2012EquilibriumMuscle::setStateVariableDeriv ( const SimTK::State &  s, const std::string &  aStateName, double  aValue  ) const

protected

Sets the derivative of an actuator state specified by name.

Parameters

s	The state.
aStateName	The name of the state to set.
aValue	The value to which the state should be set.

setTendonForceLengthCurve()

void OpenSim::Millard2012EquilibriumMuscle::setTendonForceLengthCurve

(

TendonForceLengthCurve &

aTendonForceLengthCurve

)

Parameters

aTendonForceLengthCurve

The TendonForceLengthCurve used by the muscle model to calculate the force exerted by the tendon as a function of tendon length.

upd_activation_time_constant()

double& OpenSim::Millard2012EquilibriumMuscle::upd_activation_time_constant ( )

inline

Get a writable reference to the activation_time_constant property.

upd_ActiveForceLengthCurve()

ActiveForceLengthCurve& OpenSim::Millard2012EquilibriumMuscle::upd_ActiveForceLengthCurve ( )

inline

Get a writable reference to the ActiveForceLengthCurve property.

upd_deactivation_time_constant()

double& OpenSim::Millard2012EquilibriumMuscle::upd_deactivation_time_constant ( )

inline

Get a writable reference to the deactivation_time_constant property.

upd_default_activation()

double& OpenSim::Millard2012EquilibriumMuscle::upd_default_activation ( )

inline

Get a writable reference to the default_activation property.

upd_default_fiber_length()

double& OpenSim::Millard2012EquilibriumMuscle::upd_default_fiber_length ( )

inline

Get a writable reference to the default_fiber_length property.

upd_fiber_damping()

double& OpenSim::Millard2012EquilibriumMuscle::upd_fiber_damping ( )

inline

Get a writable reference to the fiber_damping property.

upd_FiberForceLengthCurve()

FiberForceLengthCurve& OpenSim::Millard2012EquilibriumMuscle::upd_FiberForceLengthCurve ( )

inline

Get a writable reference to the FiberForceLengthCurve property.

upd_ForceVelocityCurve()

ForceVelocityCurve& OpenSim::Millard2012EquilibriumMuscle::upd_ForceVelocityCurve ( )

inline

Get a writable reference to the ForceVelocityCurve property.

upd_maximum_pennation_angle()

double& OpenSim::Millard2012EquilibriumMuscle::upd_maximum_pennation_angle ( )

inline

Get a writable reference to the maximum_pennation_angle property.

upd_minimum_activation()

double& OpenSim::Millard2012EquilibriumMuscle::upd_minimum_activation ( )

inline

Get a writable reference to the minimum_activation property.

upd_TendonForceLengthCurve()

TendonForceLengthCurve& OpenSim::Millard2012EquilibriumMuscle::upd_TendonForceLengthCurve ( )

inline

Get a writable reference to the TendonForceLengthCurve property.

OpenSim Property, Socket, Output, Input Documentation

activation_time_constant

double OpenSim::Millard2012EquilibriumMuscle::activation_time_constant

"Activation time constant (in 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.

See also

get_activation_time_constant(), upd_activation_time_constant(), set_activation_time_constant()

ActiveForceLengthCurve

ActiveForceLengthCurve OpenSim::Millard2012EquilibriumMuscle::ActiveForceLengthCurve

"Active-force-length curve."

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

See also

get_ActiveForceLengthCurve(), upd_ActiveForceLengthCurve(), set_ActiveForceLengthCurve()

deactivation_time_constant

double OpenSim::Millard2012EquilibriumMuscle::deactivation_time_constant

"Deactivation time constant (in 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.

See also

get_deactivation_time_constant(), upd_deactivation_time_constant(), set_deactivation_time_constant()

default_activation

double OpenSim::Millard2012EquilibriumMuscle::default_activation

"Assumed initial activation level if none is assigned."

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.

See also

get_default_activation(), upd_default_activation(), set_default_activation()

default_fiber_length

double OpenSim::Millard2012EquilibriumMuscle::default_fiber_length

"Assumed initial fiber length if none is assigned."

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

See also

get_default_fiber_length(), upd_default_fiber_length(), set_default_fiber_length()

fiber_damping

double OpenSim::Millard2012EquilibriumMuscle::fiber_damping

"The linear damping of the fiber."

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.

See also

get_fiber_damping(), upd_fiber_damping(), set_fiber_damping()

FiberForceLengthCurve

FiberForceLengthCurve OpenSim::Millard2012EquilibriumMuscle::FiberForceLengthCurve

"Passive-force-length curve."

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

See also

get_FiberForceLengthCurve(), upd_FiberForceLengthCurve(), set_FiberForceLengthCurve()

ForceVelocityCurve

ForceVelocityCurve OpenSim::Millard2012EquilibriumMuscle::ForceVelocityCurve

"Force-velocity curve."

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

See also

get_ForceVelocityCurve(), upd_ForceVelocityCurve(), set_ForceVelocityCurve()

maximum_pennation_angle

double OpenSim::Millard2012EquilibriumMuscle::maximum_pennation_angle

"Maximum pennation angle (in radians)."

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

See also

get_maximum_pennation_angle(), upd_maximum_pennation_angle(), set_maximum_pennation_angle()

minimum_activation

double OpenSim::Millard2012EquilibriumMuscle::minimum_activation

"Activation lower bound."

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

See also

get_minimum_activation(), upd_minimum_activation(), set_minimum_activation()

passive_fiber_damping_force

double OpenSim::Millard2012EquilibriumMuscle::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::Millard2012EquilibriumMuscle::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::Millard2012EquilibriumMuscle::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::Millard2012EquilibriumMuscle::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.

TendonForceLengthCurve

TendonForceLengthCurve OpenSim::Millard2012EquilibriumMuscle::TendonForceLengthCurve

"Tendon-force-length curve."

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

See also

get_TendonForceLengthCurve(), upd_TendonForceLengthCurve(), set_TendonForceLengthCurve()

---

The documentation for this class was generated from the following file:

• OpenSim/Actuators/Millard2012EquilibriumMuscle.h