Goal that minimizes muscle strain during motion. More...

#include <MocoMuscleStrainGoal.h>

Inheritance diagram for MocoMuscleStrainGoal:

Public Member Functions
void	setExponent (int ex)
	Set the exponent for the strain terms.

bool	getExponent () const
	Get the current exponent value.

void	setDivideByDisplacement (bool tf)
	Set whether to divide by displacement.

bool	getDivideByDisplacement () const
	Get whether the goal is divided by displacement.

Constructors
	MocoMuscleStrainGoal ()
	Default constructor.

	MocoMuscleStrainGoal (std::string name)
	Constructor with name.

	MocoMuscleStrainGoal (std::string name, double weight)
	Constructor with name and weight.

Protected Member Functions
Required implementations of virtual methods
Mode	getDefaultModeImpl () const override
	Get the default mode for this goal.

bool	getSupportsEndpointConstraintImpl () const override
	Whether this goal supports endpoint constraint mode.

void	initializeOnModelImpl (const Model &) const override
	Initialize the goal with the model.

void	calcIntegrandImpl (const IntegrandInput &input, double &integrand) const override
	Calculate the integrand value for the cost function.

void	calcGoalImpl (const GoalInput &input, SimTK::Vector &cost) const override
	Calculate the goal value.

SimTK::Matrix	FlattenSpatialVec (const SimTK::SpatialVec &S) const
	Convert a spatial vector to a matrix representation.

Private Member Functions
	OpenSim_DECLARE_CONCRETE_OBJECT (MocoMuscleStrainGoal, MocoGoal)

void	constructProperties ()
	Initialize the goal's properties.

Properties
	OpenSim_DECLARE_PROPERTY (divide_by_displacement, bool, "Divide by the model's displacement over the phase (default: " "false)")

	OpenSim_DECLARE_PROPERTY (exponent, int, "The exponent applied to the output value in the integrand. " "The output can take on negative values in the integrand when the " "exponent is set to 1 (the default value). When the exponent is " "set to a value greater than 1, the absolute value function is " "applied to the output (before the exponent is applied), meaning " "that odd numbered exponents (greater than 1) do not take on " "negative values.")

Private Attributes
Internal working variables
std::vector< std::string >	m_force_names

std::function< double(const double &)>	m_power_function
	Function to compute power of values.

std::vector< int >	m_act_indices
	Indices of muscle activation states.

std::vector< double >	m_Fiso
	Maximum isometric forces for each muscle.

std::vector< double >	m_Lopt
	Optimal fiber lengths for each muscle.

std::vector< double >	m_Vol
	Muscle volumes.

Detailed Description

Goal that minimizes muscle strain during motion.

This goal minimizes the strain experienced by muscles during the motion, integrated over the phase. The strain is computed based on the muscle's current length relative to its optimal fiber length.

The goal accounts for:

Muscle fiber lengths
Optimal fiber lengths
Muscle volumes
Maximum isometric forces

This goal can be useful for:

Preventing excessive muscle stretching
Reducing risk of muscle injury
Generating more physiologically realistic motions
Maintaining muscle lengths within normal operating ranges

The strain values can be raised to a specified power using the exponent property, and can optionally be divided by the total displacement of the model during the phase to make the cost invariant to the distance traveled.

Constructor & Destructor Documentation

◆ MocoMuscleStrainGoal() [1/3]

MocoMuscleStrainGoal ( )

inline

Default constructor.

◆ MocoMuscleStrainGoal() [2/3]

MocoMuscleStrainGoal ( std::string name )

inline

Constructor with name.

Parameters

name	The name of the goal

◆ MocoMuscleStrainGoal() [3/3]

MocoMuscleStrainGoal	(	std::string	name,
		double	weight )

inline

Constructor with name and weight.

Parameters

name	The name of the goal
weight	Weight for this goal term in the optimization

Member Function Documentation

◆ calcGoalImpl()

void calcGoalImpl	(	const GoalInput &	input,
		SimTK::Vector &	cost ) const

overrideprotected

Calculate the goal value.

Parameters

input	Input data containing the integral
cost	Vector to store the calculated cost

◆ calcIntegrandImpl()

void calcIntegrandImpl	(	const IntegrandInput &	input,
		double &	integrand ) const

overrideprotected

Calculate the integrand value for the cost function.

Parameters

input	Input data for the current state
integrand	Reference to store the calculated integrand value

◆ constructProperties()

void constructProperties ( )

private

Initialize the goal's properties.

◆ FlattenSpatialVec()

SimTK::Matrix FlattenSpatialVec ( const SimTK::SpatialVec & S ) const

protected

Convert a spatial vector to a matrix representation.

Parameters

S	Spatial vector to flatten

Returns: Matrix representation

◆ getDefaultModeImpl()

Mode getDefaultModeImpl ( ) const

inlineoverrideprotected

Get the default mode for this goal.

◆ getDivideByDisplacement()

bool getDivideByDisplacement ( ) const

inline

Get whether the goal is divided by displacement.

Returns: True if divided by displacement, false otherwise

◆ getExponent()

bool getExponent ( ) const

inline

Get the current exponent value.

Returns: The exponent value

◆ getSupportsEndpointConstraintImpl()

bool getSupportsEndpointConstraintImpl ( ) const

inlineoverrideprotected

Whether this goal supports endpoint constraint mode.

◆ initializeOnModelImpl()

void initializeOnModelImpl ( const Model & model ) const

overrideprotected

Initialize the goal with the model.

◆ OpenSim_DECLARE_CONCRETE_OBJECT()

OpenSim_DECLARE_CONCRETE_OBJECT	(	MocoMuscleStrainGoal	,
		MocoGoal	)

private

◆ OpenSim_DECLARE_PROPERTY() [1/2]

OpenSim_DECLARE_PROPERTY	(	divide_by_displacement	,
		bool	,
		"Divide by the model's displacement over the phase (default: " "false)"	)

private

◆ OpenSim_DECLARE_PROPERTY() [2/2]

OpenSim_DECLARE_PROPERTY	(	exponent	,
		int	,
		"The exponent applied to the output value in the integrand. " "The output can take on negative values in the integrand when the " "exponent is set to 1 (the default value). When the exponent is " "set to a value greater than	1,
		the absolute value function is " "applied to the	outputbefore the exponent is applied,
		meaning " "that odd numbered exponents(greater than 1) do not take on " "negative values."	)

private

◆ setDivideByDisplacement()

void setDivideByDisplacement ( bool tf )

inline

Set whether to divide by displacement.

Parameters

tf	True to divide by displacement, false otherwise

◆ setExponent()

void setExponent ( int ex )

inline

Set the exponent for the strain terms.

Parameters

ex	The exponent value

Member Data Documentation

◆ m_act_indices

std::vector<int> m_act_indices

mutableprivate

Indices of muscle activation states.

◆ m_Fiso

std::vector<double> m_Fiso

mutableprivate

Maximum isometric forces for each muscle.

◆ m_force_names

std::vector<std::string> m_force_names

mutableprivate

Names of forces used in calculations

◆ m_Lopt

std::vector<double> m_Lopt

mutableprivate

Optimal fiber lengths for each muscle.

◆ m_power_function

std::function<double(const double&)> m_power_function

mutableprivate

Function to compute power of values.

◆ m_Vol

std::vector<double> m_Vol

mutableprivate

Muscle volumes.

The documentation for this class was generated from the following files:

F:/dev/projects/MocoExtendProblem/custom_goals_compat/MocoMuscleStrainGoal/MocoMuscleStrainGoal.h
F:/dev/projects/MocoExtendProblem/custom_goals_compat/MocoMuscleStrainGoal/MocoMuscleStrainGoal.cpp

Public Member Functions

Protected Member Functions

Private Member Functions

Private Attributes

Detailed Description

Constructor & Destructor Documentation

◆ MocoMuscleStrainGoal() [1/3]

◆ MocoMuscleStrainGoal() [2/3]

◆ MocoMuscleStrainGoal() [3/3]

Member Function Documentation

◆ calcGoalImpl()

◆ calcIntegrandImpl()

◆ constructProperties()

◆ FlattenSpatialVec()

◆ getDefaultModeImpl()

◆ getDivideByDisplacement()

◆ getExponent()

◆ getSupportsEndpointConstraintImpl()

◆ initializeOnModelImpl()

◆ OpenSim_DECLARE_CONCRETE_OBJECT()

◆ OpenSim_DECLARE_PROPERTY() [1/2]

◆ OpenSim_DECLARE_PROPERTY() [2/2]

◆ setDivideByDisplacement()

◆ setExponent()

Member Data Documentation

◆ m_act_indices

◆ m_Fiso

◆ m_force_names

◆ m_Lopt

◆ m_power_function

◆ m_Vol