artisynth.core.materials

Class LinearAxialMuscle

java.lang.Object

artisynth.core.materials.MaterialBase

artisynth.core.materials.AxialMaterial

artisynth.core.materials.AxialMuscleMaterialBase

artisynth.core.materials.AxialMuscleMaterial

artisynth.core.materials.LinearAxialMuscle

All Implemented Interfaces:

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

public class LinearAxialMuscle
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
LinearAxialMuscle() Constructs a new LinearAxialMuscle.
LinearAxialMuscle(double fmax, double lrest) Deprecated. For historical reasons, this constructor sets the deprecated forceScaling property to 1000, thuis scaling the effective value of fmax.
LinearAxialMuscle(double fmax, double lopt, double lmax, double pfrac) Constructs a new LinearAxialMuscle with specified properties.
LinearAxialMuscle(double fmax, double lopt, double lmax, double pfrac, double damping) Constructs a new LinearAxialMuscle with specified properties.

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 LinearAxialMuscle	create() Creates a new LinearAxialMuscle with default values.
static LinearAxialMuscle	create(double fmax, double lrest) Creates a new LinearAxialMuscle 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

LinearAxialMuscle

public LinearAxialMuscle()

Constructs a new LinearAxialMuscle.

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

LinearAxialMuscle

public LinearAxialMuscle(double fmax,
                         double lrest)

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

Constructs a new LinearAxialMuscle with a specified maximum force. The optLength and maxLength properties are set to lrest and 1.5 lrest, passiveFraction is set to 1, and the damping property is set to 0.

Parameters:

fmax - maximum contractile force

lrest - sets the optLength and maxLength properties

LinearAxialMuscle

public LinearAxialMuscle(double fmax,
                         double lopt,
                         double lmax,
                         double pfrac)

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

Parameters:

fmax - maximum contractile force

lopt - length below which zero active force is generated

lmax - length beyond which maximum active and passive force is generated

pfrac - passive fraction of fmax that forms the maximum passive force

LinearAxialMuscle

public LinearAxialMuscle(double fmax,
                         double lopt,
                         double lmax,
                         double pfrac,
                         double damping)

Constructs a new LinearAxialMuscle with specified properties. The deprecated forceScaling property is set to 1.

Parameters:

fmax - maximum contractile force

lopt - length below which zero active force is generated

lmax - length beyond which maximum active and passive force is generated

pfrac - passive fraction of fmax that forms the maximum passive force

damping - damping term

Method Detail

create

public static LinearAxialMuscle create()

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

Returns:

created material

create

public static LinearAxialMuscle create(double fmax,
                                       double lrest)

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

Parameters:

fmax - maximum contractile force

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