Thelen2003AxialMuscle (Artisynth API documentation)

java.lang.Object
- artisynth.core.materials.MaterialBase
- - artisynth.core.materials.AxialMaterial
  - - artisynth.core.materials.AxialMuscleMaterialBase
    - - artisynth.core.materials.EquilibriumAxialMuscle
      - artisynth.core.materials.Thelen2003AxialMuscle

All Implemented Interfaces:

HasMaterialState, HasNumericState, PostScannable, ScalableUnits, java.lang.Cloneable, CompositeProperty, HasProperties, Clonable, Scannable
```
public class Thelen2003AxialMuscle
extends EquilibriumAxialMuscle
implements HasNumericState
```
Implements the Thelen2003Muscle from OpenSim. One should consult the OpenSim API documentation for a detailed explanation of the muscle model's parameters and behavior. The names of this class's muscle parameter properties should match the OpenSim equivalents closely enough to be unambiguous.
The force velocity curve has been modified to remove a derivative discontinuity at vn = 0, where vn is the normalized velocity.
Equilbrium muscle models contain a muscle component and tendon component in series. The muscle and tendon lengths sum to the combined length l that is supplied the the method EquilibriumAxialMuscle.computeF(double, double, double, double), which computes the muacle tension, while the equilibrum condition implies that the tension from the muscle and tendon components must both equal the value returned by EquilibriumAxialMuscle.computeF(double, double, double, double). To implement this, we store the muscle length as a state variable which is updated at each time step to ensure that the equilbrium condition is satisfied. We do this differently from OpenSim: rather than solving for and then integrating the muscle velocity, the velocity inferred by dividing the cnange in muscle length by the time step size. This avoids the singularity that arises in the OpenSim method at zero activation, and so removes the need for always ensuring that the activation is non-zero.
We also a support, via the rigidTendon property, a mode where the tendon is considered to be rigid (via the rigidTendon property), which simplifies the computation in situations where this approximation is acceptable.

Field Summary

Fields
Modifier and Type	Field and Description
`static double`	`DEFAULT_AF`
`static double`	`DEFAULT_FLEN`
`static double`	`DEFAULT_FMAX_MUSCLE_STRAIN`
`static double`	`DEFAULT_FMAX_TENDON_STRAIN`
`static double`	`DEFAULT_FV_LINEAR_EXTRAP_THRESHOLD`
`static double`	`DEFAULT_K_SHAPE_ACTIVE`
`static double`	`DEFAULT_K_SHAPE_PASSIVE`
`static double`	`DEFAULT_MAX_PENNATION_ANGLE`
`static double`	`DEFAULT_MINIMUM_ACTIVATION`
`static PropertyList`	`myProps`

Fields inherited from class artisynth.core.materials.EquilibriumAxialMuscle
debug, DEFAULT_COMPUTE_LMDOT_FROM_LDOT, DEFAULT_FIBRE_DAMPING, DEFAULT_IGNORE_FORCE_VELOCITY, DEFAULT_MAX_CONTRACTION_VELOCITY, DEFAULT_MAX_ISO_FORCE, DEFAULT_MUSCLE_LENGTH, DEFAULT_OPT_FIBRE_LENGTH, DEFAULT_OPT_PENNATION_ANGLE, DEFAULT_RIGID_TENDON, DEFAULT_TENDON_SLACK_LENGTH, useFindLm, useNewtonSolver, vmFromTendon

Constructor Summary

Constructors
Constructor and Description
`Thelen2003AxialMuscle()`
`Thelen2003AxialMuscle(double fmax, double lopt, double tslack, double optPenAng)`

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`Thelen2003AxialMuscle`	`clone()` Returns a clone of this composite property.
`double`	`getAf()`
`PropertyList`	`getAllPropertyInfo()` Returns a list giving static information about all properties exported by this object.
`double`	`getFlen()`
`double`	`getFmaxMuscleStrain()`
`double`	`getFmaxTendonStrain()`
`double`	`getFvLinearExtrapThreshold()`
`double`	`getKShapeActive()`
`double`	`getKShapePassive()`
`double`	`getMaxPennationAngle()`
`double`	`getMinimumActivation()`
`static void`	`main(java.lang.String[] args)`
`void`	`setAf(double af)`
`void`	`setFlen(double flen)`
`void`	`setFmaxMuscleStrain(double fts)`
`void`	`setFmaxTendonStrain(double fts)`
`void`	`setFvLinearExtrapThreshold(double thresh)`
`void`	`setKShapeActive(double kshape)`
`void`	`setKShapePassive(double kshape)`
`void`	`setMaxPennationAngle(double ang)`
`void`	`setMinimumActivation(double mina)`

Methods inherited from class artisynth.core.materials.EquilibriumAxialMuscle
advanceState, computeDFdl, computeDFdldot, computeF, computeG, computeLmWithConstantVm, computeLmWithVmFromLm, computePassiveF, computeVmFromLdot, fibreToMuscleLength, getComputeLmDotFromLDot, getFibreDamping, getIgnoreForceVelocity, getIgnoreTendonCompliance, getLength, getMaxContractionVelocity, getMaxIsoForce, getMuscleLength, getOptFibreLength, getOptPennationAngle, getState, getTendonLength, getTendonSlackLength, hasRigidTendon, hasState, initializeLmPrevFromLdot, isDFdldotZero, requiresAdvance, scaleDistance, scaleMass, setComputeLmDotFromLDot, setFibreDamping, setIgnoreForceVelocity, setIgnoreTendonCompliance, setLength, setMaxContractionVelocity, setMaxIsoForce, setMuscleLength, setOptFibreLength, setOptPennationAngle, setRigidTendon, setState, setTendonSlackLength, writeActiveForceLengthCurve, writeForceVelocityCurve, writePassiveForceLengthCurve, writeTendonForceLengthCurve

Methods inherited from class artisynth.core.materials.AxialMaterial
equals, equals, getSubClasses

Methods inherited from class artisynth.core.materials.MaterialBase
advanceState, createStateObject, getProperty, getPropertyHost, getPropertyInfo, hasProperty, hasSymmetricTangent, isWritable, postscan, scan, setPropertyHost, setPropertyInfo, symmetryOrStateChanged, updateMaterial, write, writeItems

Methods inherited from class java.lang.Object
getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface artisynth.core.modelbase.HasNumericState
advanceState, getAuxVarDerivative, getAuxVarState, getState, getStateVersion, hasState, numAuxVars, requiresAdvance, setAuxVarState, setState

Field Detail

DEFAULT_FMAX_TENDON_STRAIN

public static double DEFAULT_FMAX_TENDON_STRAIN

DEFAULT_FMAX_MUSCLE_STRAIN

public static double DEFAULT_FMAX_MUSCLE_STRAIN

DEFAULT_K_SHAPE_ACTIVE

public static double DEFAULT_K_SHAPE_ACTIVE

DEFAULT_K_SHAPE_PASSIVE

public static double DEFAULT_K_SHAPE_PASSIVE

DEFAULT_AF
```
public static double DEFAULT_AF
```

DEFAULT_FLEN
```
public static double DEFAULT_FLEN
```

DEFAULT_FV_LINEAR_EXTRAP_THRESHOLD

public static double DEFAULT_FV_LINEAR_EXTRAP_THRESHOLD

DEFAULT_MAX_PENNATION_ANGLE

public static double DEFAULT_MAX_PENNATION_ANGLE

DEFAULT_MINIMUM_ACTIVATION

public static double DEFAULT_MINIMUM_ACTIVATION

myProps
```
public static PropertyList myProps
```

Constructor Detail

Thelen2003AxialMuscle
```
public Thelen2003AxialMuscle()
```

Thelen2003AxialMuscle

public Thelen2003AxialMuscle(double fmax,
                             double lopt,
                             double tslack,
                             double optPenAng)

Method Detail
- getAllPropertyInfo
```
public PropertyList getAllPropertyInfo()
```
  Description copied from interface: HasProperties
  
  Returns a list giving static information about all properties exported by this object.
  
  Specified by:
  
  getAllPropertyInfo in interface HasProperties
  
  Overrides:
  
  getAllPropertyInfo in class EquilibriumAxialMuscle
  
  Returns:
  
  static information for all exported properties
- getFmaxTendonStrain
```
public double getFmaxTendonStrain()
```
- setFmaxTendonStrain
```
public void setFmaxTendonStrain(double fts)
```
- getFmaxMuscleStrain
```
public double getFmaxMuscleStrain()
```
- setFmaxMuscleStrain
```
public void setFmaxMuscleStrain(double fts)
```
- getKShapeActive
```
public double getKShapeActive()
```
- setKShapeActive
```
public void setKShapeActive(double kshape)
```
- getKShapePassive
```
public double getKShapePassive()
```
- setKShapePassive
```
public void setKShapePassive(double kshape)
```
- getAf
```
public double getAf()
```
- setAf
```
public void setAf(double af)
```
- getFlen
```
public double getFlen()
```
- setFlen
```
public void setFlen(double flen)
```
- getFvLinearExtrapThreshold
```
public double getFvLinearExtrapThreshold()
```
- setFvLinearExtrapThreshold
```
public void setFvLinearExtrapThreshold(double thresh)
```
- getMaxPennationAngle
```
public double getMaxPennationAngle()
```
- setMaxPennationAngle
```
public void setMaxPennationAngle(double ang)
```
- getMinimumActivation
```
public double getMinimumActivation()
```
- setMinimumActivation
```
public void setMinimumActivation(double mina)
```
- clone
```
public Thelen2003AxialMuscle clone()
```
  Description copied from interface: CompositeProperty
  
  Returns a clone of this composite property.
  
  Specified by:
  
  clone in interface CompositeProperty
  
  Specified by:
  
  clone in interface Clonable
  
  Overrides:
  
  clone in class AxialMaterial
  
  Returns:
  
  clone of this property
- main
```
public static void main(java.lang.String[] args)
                 throws java.io.IOException
```
  Throws:
  
  java.io.IOException

Class Thelen2003AxialMuscle

Field Summary

Fields inherited from class artisynth.core.materials.EquilibriumAxialMuscle

Constructor Summary

Method Summary

Methods inherited from class artisynth.core.materials.EquilibriumAxialMuscle

Methods inherited from class artisynth.core.materials.AxialMaterial

Methods inherited from class artisynth.core.materials.MaterialBase

Methods inherited from class java.lang.Object

Methods inherited from interface artisynth.core.modelbase.HasNumericState

Field Detail

DEFAULT_FMAX_TENDON_STRAIN

DEFAULT_FMAX_MUSCLE_STRAIN

DEFAULT_K_SHAPE_ACTIVE

DEFAULT_K_SHAPE_PASSIVE

DEFAULT_AF

DEFAULT_FLEN

DEFAULT_FV_LINEAR_EXTRAP_THRESHOLD

DEFAULT_MAX_PENNATION_ANGLE

DEFAULT_MINIMUM_ACTIVATION

myProps

Constructor Detail

Thelen2003AxialMuscle

Thelen2003AxialMuscle

Method Detail

getAllPropertyInfo

getFmaxTendonStrain

setFmaxTendonStrain

getFmaxMuscleStrain

setFmaxMuscleStrain

getKShapeActive

setKShapeActive

getKShapePassive

setKShapePassive

getAf

setAf

getFlen

setFlen

getFvLinearExtrapThreshold

setFvLinearExtrapThreshold

getMaxPennationAngle

setMaxPennationAngle

getMinimumActivation

setMinimumActivation

clone

main