API  4.1 For C++ developers
OpenSim::Muscle::FiberVelocityInfo Struct Reference

FiberVelocityInfo contains velocity quantities related to the velocity of the muscle (fiber + tendon) complex. More...

## Public Member Functions

FiberVelocityInfo ()

## Public Attributes

double fiberVelocity

double fiberVelocityAlongTendon

double normFiberVelocity

double pennationAngularVelocity

double tendonVelocity

double normTendonVelocity

double fiberForceVelocityMultiplier

SimTK::Vector userDefinedVelocityExtras

## Friends

std::ostream & operator<< (std::ostream &o, const FiberVelocityInfo &fvi)

## Detailed Description

FiberVelocityInfo contains velocity quantities related to the velocity of the muscle (fiber + tendon) complex.

The function that populates this struct, calcFiberVelocityInfo, is called when position and velocity information is known. This function is the second function that is called of these related functions:calcMuscleLengthInfo,calcFiberVelocityInfo and calcMuscleDynamicInfo. When calcFiberVelocity is called the acceleration of the muscle path, and any forces the muscle experiences will not be known.

NAME                     DIMENSION             UNITS
fiberVelocity             length/time           m/s
fiberVelocityAlongTendon  length/time           m/s       [1]
normFiberVelocity         (length/time)/Vmax    NA        [2]

tendonVelocity            length/time           m/s
normTendonVelocity        (length/time)/length  (m/s)/m   [4]

fiberForceVelocityMultiplier force/force          NA        [5]

userDefinedVelocityExtras    NA                   NA      [6]


[1] fiberVelocityAlongTendon is the first derivative of the symbolic equation that defines the fiberLengthAlongTendon.

[2] normFiberVelocity is the fiberVelocity (in m/s) divided by the optimal length of the fiber (in m) and by the maximum fiber velocity (in optimal-fiber-lengths/s). normFiberVelocity has units of 1/optimal-fiber-length.

[3] The sign of the angular velocity is defined using the right hand rule.

[4] normTendonVelocity is the tendonVelocity (the lengthening velocity of the tendon) divided by its resting length

[5] The fiberForceVelocityMultiplier is the scaling factor that represents how a muscle fiber's force generating capacity is modulated by the contraction (concentric or eccentric) velocity of the fiber. Generally this curve has a value of 1 at a fiber velocity of 0, has a value of between 1.4-1.8 at the maximum eccentric contraction velocity and a value of 0 at the maximum concentric contraction velocity. The force velocity curve, which computes this term, is usually an interpolation of an experimental curve.

[6] This vector is left for the muscle modeler to populate with any computationally expensive quantities that are computed in calcFiberVelocityInfo, and required for use in the user defined function calcMuscleDynamicsInfo. None of the parent classes make any assumptions about what is or isn't in this field

• use as necessary.

## ◆ FiberVelocityInfo()

 OpenSim::Muscle::FiberVelocityInfo::FiberVelocityInfo ( )
inline

## ◆ operator<<

 std::ostream& operator<< ( std::ostream & o, const FiberVelocityInfo & fvi )
friend

## ◆ fiberForceVelocityMultiplier

 double OpenSim::Muscle::FiberVelocityInfo::fiberForceVelocityMultiplier

## ◆ fiberVelocity

 double OpenSim::Muscle::FiberVelocityInfo::fiberVelocity

## ◆ fiberVelocityAlongTendon

 double OpenSim::Muscle::FiberVelocityInfo::fiberVelocityAlongTendon

## ◆ normFiberVelocity

 double OpenSim::Muscle::FiberVelocityInfo::normFiberVelocity

## ◆ normTendonVelocity

 double OpenSim::Muscle::FiberVelocityInfo::normTendonVelocity

## ◆ pennationAngularVelocity

 double OpenSim::Muscle::FiberVelocityInfo::pennationAngularVelocity

## ◆ tendonVelocity

 double OpenSim::Muscle::FiberVelocityInfo::tendonVelocity

## ◆ userDefinedVelocityExtras

 SimTK::Vector OpenSim::Muscle::FiberVelocityInfo::userDefinedVelocityExtras

The documentation for this struct was generated from the following file:
• OpenSim/Simulation/Model/Muscle.h