artisynth.core.materials

Class EquilibriumAxialMuscle

java.lang.Object

artisynth.core.materials.MaterialBase

artisynth.core.materials.AxialMaterial

artisynth.core.materials.AxialMuscleMaterialBase

artisynth.core.materials.EquilibriumAxialMuscle

All Implemented Interfaces:

HasMaterialState, PostScannable, ScalableUnits, java.lang.Cloneable, CompositeProperty, HasProperties, Clonable, Scannable

Direct Known Subclasses:

Millard2012AxialMuscle, Thelen2003AxialMuscle

public abstract class EquilibriumAxialMuscle
extends AxialMuscleMaterialBase

Base class for point-to-point muscle materials that implement a pennated muscle and tendon in series, and which solve for the muscle length at each time step to ensure that the muscle and tendon forces are equal.

Field Summary

Fields

Modifier and Type	Field and Description
boolean	debug
static boolean	DEFAULT_COMPUTE_LMDOT_FROM_LDOT
static double	DEFAULT_FIBRE_DAMPING
static boolean	DEFAULT_IGNORE_FORCE_VELOCITY
static double	DEFAULT_MAX_CONTRACTION_VELOCITY
static double	DEFAULT_MAX_ISO_FORCE
static double	DEFAULT_MUSCLE_LENGTH
static double	DEFAULT_OPT_FIBRE_LENGTH
static double	DEFAULT_OPT_PENNATION_ANGLE
static boolean	DEFAULT_RIGID_TENDON
static double	DEFAULT_TENDON_SLACK_LENGTH
static PropertyList	myProps
static boolean	useFindLm
static boolean	useNewtonSolver
boolean	vmFromTendon

Method Summary

Modifier and Type	Method and Description
void	advanceState(double t0, double t1)
double	computeDFdl(double l, double ldot, double l0, double excitation) Computes and returns the derivative of the axial spring tension with respect to the length.
double	computeDFdldot(double l, double ldot, double l0, double excitation) Computes and returns the derivative of the axial spring tension with respect to the length time derivative.
double	computeF(double l, double ldot, double l0, double excitation) Computes and returns the axial spring tension, as a function of length, length time derivative, rest length, and excitation.
double	computeG(DoubleHolder dG, double l, double lm, double vm, double a, double h)
double	computeLmWithConstantVm(double l, double vm, double a)
double	computeLmWithVmFromLm(double l, double ldot, double a, double h)
double	computePassiveF(double l, double ldot, double l0, double excitation)
double	computeVmFromLdot(double ldot)
double	fibreToMuscleLength(double lf) Computes the muscle length corresponding to a given fibre length.
PropertyList	getAllPropertyInfo() Returns a list giving static information about all properties exported by this object.
boolean	getComputeLmDotFromLDot()
double	getFibreDamping()
boolean	getIgnoreForceVelocity()
boolean	getIgnoreTendonCompliance() Deprecated. Use hasRigidTendon() instead.
double	getLength()
double	getMaxContractionVelocity()
double	getMaxIsoForce()
double	getMuscleLength()
double	getOptFibreLength()
double	getOptPennationAngle()
void	getState(DataBuffer data)
double	getTendonLength()
double	getTendonSlackLength()
boolean	hasRigidTendon() Queries whether the tendon for this muscle material is rigid.
boolean	hasState()
double	initializeLmPrevFromLdot(double l, double ldot, double a)
boolean	isDFdldotZero() Returns true if computeDFdldot() always returns zero.
boolean	requiresAdvance()
void	scaleDistance(double s) Scales all distance coordinates.
void	scaleMass(double s) Scales all mass units.
void	setComputeLmDotFromLDot(boolean enable)
void	setFibreDamping(double d)
void	setIgnoreForceVelocity(boolean enable)
void	setIgnoreTendonCompliance(boolean enable) Deprecated. Use setRigidTendon(boolean) instead.
void	setLength(double l)
void	setMaxContractionVelocity(double maxv)
void	setMaxIsoForce(double fmax)
void	setMuscleLength(double l)
void	setOptFibreLength(double l)
void	setOptPennationAngle(double ang)
void	setRigidTendon(boolean enable) Set whether the tendon for this muscle material is rigid.
void	setState(DataBuffer data)
void	setTendonSlackLength(double l)
void	writeActiveForceLengthCurve(java.lang.String fileName, double x0, double x1, int npnts, java.lang.String fmtStr)
void	writeForceVelocityCurve(java.lang.String fileName, double a, double x0, double x1, int npnts, java.lang.String fmtStr)
void	writePassiveForceLengthCurve(java.lang.String fileName, double x0, double x1, int npnts, java.lang.String fmtStr)
void	writeTendonForceLengthCurve(java.lang.String fileName, double x0, double x1, int npnts, java.lang.String fmtStr)

Methods inherited from class artisynth.core.materials.AxialMaterial

clone, 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

Field Detail

useNewtonSolver

public static boolean useNewtonSolver

useFindLm

public static boolean useFindLm

vmFromTendon

public boolean vmFromTendon

DEFAULT_MAX_ISO_FORCE

public static double DEFAULT_MAX_ISO_FORCE

DEFAULT_OPT_FIBRE_LENGTH

public static double DEFAULT_OPT_FIBRE_LENGTH

DEFAULT_TENDON_SLACK_LENGTH

public static double DEFAULT_TENDON_SLACK_LENGTH

DEFAULT_OPT_PENNATION_ANGLE

public static double DEFAULT_OPT_PENNATION_ANGLE

DEFAULT_MAX_CONTRACTION_VELOCITY

public static double DEFAULT_MAX_CONTRACTION_VELOCITY

DEFAULT_FIBRE_DAMPING

public static double DEFAULT_FIBRE_DAMPING

DEFAULT_RIGID_TENDON

public static boolean DEFAULT_RIGID_TENDON

DEFAULT_IGNORE_FORCE_VELOCITY

public static boolean DEFAULT_IGNORE_FORCE_VELOCITY

DEFAULT_COMPUTE_LMDOT_FROM_LDOT

public static boolean DEFAULT_COMPUTE_LMDOT_FROM_LDOT

DEFAULT_MUSCLE_LENGTH

public static double DEFAULT_MUSCLE_LENGTH

myProps

public static PropertyList myProps

debug

public boolean debug

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 MaterialBase

Returns:

static information for all exported properties

getMaxIsoForce

public double getMaxIsoForce()

setMaxIsoForce

public void setMaxIsoForce(double fmax)

getOptFibreLength

public double getOptFibreLength()

setOptFibreLength

public void setOptFibreLength(double l)

getTendonSlackLength

public double getTendonSlackLength()

setTendonSlackLength

public void setTendonSlackLength(double l)

getOptPennationAngle

public double getOptPennationAngle()

setOptPennationAngle

public void setOptPennationAngle(double ang)

getMaxContractionVelocity

public double getMaxContractionVelocity()

setMaxContractionVelocity

public void setMaxContractionVelocity(double maxv)

getFibreDamping

public double getFibreDamping()

setFibreDamping

public void setFibreDamping(double d)

getIgnoreTendonCompliance

public boolean getIgnoreTendonCompliance()

Deprecated. Use hasRigidTendon() instead.

setIgnoreTendonCompliance

public void setIgnoreTendonCompliance(boolean enable)

Deprecated. Use setRigidTendon(boolean) instead.

hasRigidTendon

public boolean hasRigidTendon()

Queries whether the tendon for this muscle material is rigid.

Returns:

true if the tendon is rigid

setRigidTendon

public void setRigidTendon(boolean enable)

Set whether the tendon for this muscle material is rigid.

Parameters:

enable - if true, sets the tendon rigid

getIgnoreForceVelocity

public boolean getIgnoreForceVelocity()

setIgnoreForceVelocity

public void setIgnoreForceVelocity(boolean enable)

getComputeLmDotFromLDot

public boolean getComputeLmDotFromLDot()

setComputeLmDotFromLDot

public void setComputeLmDotFromLDot(boolean enable)

getTendonLength

public double getTendonLength()

getLength

public double getLength()

setLength

public void setLength(double l)

getMuscleLength

public double getMuscleLength()

setMuscleLength

public void setMuscleLength(double l)

fibreToMuscleLength

public double fibreToMuscleLength(double lf)

Computes the muscle length corresponding to a given fibre length. If the fibre length is less that the muscle height, returns 0.

Parameters:

lf - fibre length

Returns:

corresponding muscle length

computeF

public double computeF(double l,
                       double ldot,
                       double l0,
                       double excitation)

Computes and returns the axial spring tension, as a function of length, length time derivative, rest length, and excitation.

Specified by:

computeF in class AxialMaterial

Parameters:

l - spring length

ldot - spring length time derivative

l0 - spring rest length

excitation - excitation value (varying from 0 to 1)

Returns:

spring tension

computePassiveF

public double computePassiveF(double l,
                              double ldot,
                              double l0,
                              double excitation)

computeVmFromLdot

public double computeVmFromLdot(double ldot)

initializeLmPrevFromLdot

public double initializeLmPrevFromLdot(double l,
                                       double ldot,
                                       double a)

computeLmWithConstantVm

public double computeLmWithConstantVm(double l,
                                      double vm,
                                      double a)

computeLmWithVmFromLm

public double computeLmWithVmFromLm(double l,
                                    double ldot,
                                    double a,
                                    double h)

computeG

public double computeG(DoubleHolder dG,
                       double l,
                       double lm,
                       double vm,
                       double a,
                       double h)

computeDFdl

public double computeDFdl(double l,
                          double ldot,
                          double l0,
                          double excitation)

Computes and returns the derivative of the axial spring tension with respect to the length.

Specified by:

computeDFdl in class AxialMaterial

Parameters:

l - spring length

ldot - spring length time derivative

l0 - spring rest length

excitation - excitation value (varying from 0 to 1)

Returns:

tension derivative with respect to length

computeDFdldot

public double computeDFdldot(double l,
                             double ldot,
                             double l0,
                             double excitation)

Computes and returns the derivative of the axial spring tension with respect to the length time derivative.

Specified by:

computeDFdldot in class AxialMaterial

Parameters:

l - spring length

ldot - spring length time derivative

l0 - spring rest length

excitation - excitation value (varying from 0 to 1)

Returns:

tension derivative with respect to length time derivative

isDFdldotZero

public boolean isDFdldotZero()

Returns true if computeDFdldot() always returns zero. For a linear spring, this simply means the damping is zero. When dFdldot is always 0, then stiffness matrix will be symmetric.

Specified by:

isDFdldotZero in class AxialMaterial

hasState

public boolean hasState()

Specified by:

hasState in interface HasMaterialState

Overrides:

hasState in class MaterialBase

setState

public void setState(DataBuffer data)

getState

public void getState(DataBuffer data)

advanceState

public void advanceState(double t0,
                         double t1)

requiresAdvance

public boolean requiresAdvance()

writeActiveForceLengthCurve

public void writeActiveForceLengthCurve(java.lang.String fileName,
                                        double x0,
                                        double x1,
                                        int npnts,
                                        java.lang.String fmtStr)
                                 throws java.io.IOException

Throws:

java.io.IOException

writePassiveForceLengthCurve

public void writePassiveForceLengthCurve(java.lang.String fileName,
                                         double x0,
                                         double x1,
                                         int npnts,
                                         java.lang.String fmtStr)
                                  throws java.io.IOException

Throws:

java.io.IOException

writeTendonForceLengthCurve

public void writeTendonForceLengthCurve(java.lang.String fileName,
                                        double x0,
                                        double x1,
                                        int npnts,
                                        java.lang.String fmtStr)
                                 throws java.io.IOException

Throws:

java.io.IOException

writeForceVelocityCurve

public void writeForceVelocityCurve(java.lang.String fileName,
                                    double a,
                                    double x0,
                                    double x1,
                                    int npnts,
                                    java.lang.String fmtStr)
                             throws java.io.IOException

Throws:

java.io.IOException

scaleDistance

public void scaleDistance(double s)

Description copied from interface: ScalableUnits

Scales all distance coordinates.

Specified by:

scaleDistance in interface ScalableUnits

Overrides:

scaleDistance in class MaterialBase

Parameters:

s - scaling factor

scaleMass

public void scaleMass(double s)

Description copied from interface: ScalableUnits

Scales all mass units.

Specified by:

scaleMass in interface ScalableUnits

Overrides:

scaleMass in class MaterialBase

Parameters:

s - scaling factor