artisynth.core.materials

Class ConstantAxialMuscle

java.lang.Object

artisynth.core.materials.MaterialBase

artisynth.core.materials.AxialMaterial

artisynth.core.materials.AxialMuscleMaterialBase

artisynth.core.materials.AxialMuscleMaterial

artisynth.core.materials.ConstantAxialMuscle

All Implemented Interfaces:

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

public class ConstantAxialMuscle
extends AxialMuscleMaterial

Field Summary

Fields inherited from class artisynth.core.materials.AxialMuscleMaterial

DEFAULT_DAMPING, DEFAULT_MAX_FORCE, DEFAULT_MAX_LENGTH, DEFAULT_OPT_LENGTH, DEFAULT_PASSIVE_FRACTION, DEFAULT_SCALING, DEFAULT_TENDON_RATIO, maxStretch, minStretch, myProps

Constructor Summary

Constructors

Constructor and Description
ConstantAxialMuscle() Constructs a new ConstantAxialMuscle.
ConstantAxialMuscle(double fmax) Deprecated. For historical reasons, this constructor sets the deprecated forceScaling property to 1000, thuis scaling the effective value of fmax.
ConstantAxialMuscle(double fmax, double pfrac) Constructs a new ConstantAxialMuscle with a specified values.
ConstantAxialMuscle(double fmax, double pfrac, double damping) Constructs a new ConstantAxialMuscle with a specified values.

Method Summary

Modifier and Type	Method and Description
double	computeDFdl(double l, double ldot, double l0, double ex) 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 ex) Computes and returns the axial spring tension, as a function of length, length time derivative, rest length, and excitation.
static ConstantAxialMuscle	create() Creates a new ConstantAxialMuscle with default values.
static ConstantAxialMuscle	create(double fmax) Creates a new ConstantAxialMuscle with a specified maximum force.
boolean	isDFdldotZero() Returns true if computeDFdldot() always returns zero.

Methods inherited from class artisynth.core.materials.AxialMuscleMaterial

clone, equals, getAllPropertyInfo, getDamping, getDampingMode, getForceScaling, getForceScalingMode, getMaxForce, getMaxForceMode, getMaxLength, getMaxLengthMode, getOptLength, getOptLengthMode, getPassiveFraction, getPassiveFractionMode, getSubClasses, getTendonRatio, getTendonRatioMode, normalizeForceScaling, scaleDistance, scaleMass, setAxialMuscleMaterialProps, setDamping, setDampingMode, setForceScaling, setForceScalingMode, setMaxForce, setMaxForceMode, setMaxLength, setMaxLengthMode, setOptLength, setOptLengthMode, setPassiveFraction, setPassiveFractionMode, setTendonRatio, setTendonRatioMode, toString

Methods inherited from class artisynth.core.materials.AxialMaterial

equals

Methods inherited from class artisynth.core.materials.MaterialBase

advanceState, createStateObject, getProperty, getPropertyHost, getPropertyInfo, hasProperty, hasState, 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

Constructor Detail

ConstantAxialMuscle

public ConstantAxialMuscle()

Constructs a new ConstantAxialMuscle.

Important: for historical reasons, this constructor sets the deprecated forceScaling property to 1000, thus scaling the effective values of the maxForce and damping properties.

ConstantAxialMuscle

public ConstantAxialMuscle(double fmax)

Deprecated. For historical reasons, this constructor sets the deprecated forceScaling property to 1000, thuis scaling the effective value of fmax.

Constructs a new ConstantAxialMuscle with a specified maximum force. The passiveFraction and damping properties are both set to 0,

Parameters:

fmax - maximum contractile force

ConstantAxialMuscle

public ConstantAxialMuscle(double fmax,
                           double pfrac)

Constructs a new ConstantAxialMuscle with a specified values. The damping property is set to 0, and the deprecated forceScaling property is set to 1.

Parameters:

fmax - maximum contractile force

pfrac - passive fraction: the proportion of fmax to apply as passive tension

ConstantAxialMuscle

public ConstantAxialMuscle(double fmax,
                           double pfrac,
                           double damping)

Constructs a new ConstantAxialMuscle with a specified values. The deprecated forceScaling property is set to 1.

Parameters:

fmax - maximum contractile force

pfrac - passive fraction: the proportion of fmax to apply as passive tension

damping - damping term

Method Detail

create

public static ConstantAxialMuscle create()

Creates a new ConstantAxialMuscle with default values. The (deprecated) forceScaling term is set to 1.

Returns:

created material

create

public static ConstantAxialMuscle create(double fmax)

Creates a new ConstantAxialMuscle with a specified maximum force. The passiveFraction and damping properties are both set to 0, and the deprecated forceScaling property is set to 1.

Parameters:

fmax - maximum contractile force

Returns:

created material

computeF

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

Description copied from class: AxialMaterial

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

ex - excitation value (varying from 0 to 1)

Returns:

spring tension

computeDFdl

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

Description copied from class: AxialMaterial

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

ex - 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)

Description copied from class: AxialMaterial

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()

Description copied from class: AxialMaterial

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