Description

Minimize the sum of squares of specified reaction moment and force measures for a given joint, integrated over the phase.

If the magnitude of the gravity acceleration vector (Model::get_gravity()) is non-zero, then the goal is normalized by the model's weight; otherwise, the goal is normalized by the model's mass. We assume the system's mass is constant (that is, MocoParameters do not affect mass).

In addition to specifying the joint and reaction measures, the user may also specify the frame the loads are computed from ("parent" or "child"), and the frame the loads are expressed in (any valid frame in the model).

Minimizing the y-direction reaction force on the child frame of the right knee joint expressed in the right tibia frame:

auto* cost = problem.addGoal<MocoJointReactionCost>();
cost->setName("tibiofemoral_compressive_force");
cost->setJointPath("/jointset/knee_r");
cost->setLoadsFrame("child");
cost->setExpressedInFramePath("/bodyset/tibia_r");
cost->setReactionMeasures({"force-y"});

This cost requires realizing to the Acceleration stage.

Inheritance diagram for OpenSim::MocoJointReactionGoal:

#include <Moco/Moco/MocoGoal/MocoJointReactionGoal.h>

Public Member Functions
	MocoJointReactionGoal (std::string name)

	MocoJointReactionGoal (std::string name, double weight)

void	setJointPath (const std::string &jointPath)
	Set the model path to the joint whose reaction load(s) will be minimized. More...

void	setLoadsFrame (const std::string &frame)
	Set the frame from which the reaction loads are computed. More...

void	setExpressedInFramePath (const std::string &framePath)
	Set the frame in which the minimized reaction load is expressed. More...

void	setReactionMeasures (const std::vector< std::string > &measures)
	Set a specific set of reaction measures to be minimized. More...

void	setWeight (const std::string &stateName, const double &weight)
	Set the weight for an individual reaction measure. More...

void	setWeightSet (const MocoWeightSet &weightSet)
	Provide a MocoWeightSet to weight the reaction measures in the cost. More...

Public Member Functions inherited from OpenSim::MocoGoal
	MocoGoal (std::string name)

	MocoGoal (std::string name, double weight)

void	setEnabled (bool enabled)
	Set whether this goal is used in the problem.

bool	getEnabled () const

void	setWeight (double weight)
	In cost mode, the goal is multiplied by this weight. More...

double	getWeight () const

void	setMode (std::string mode)
	Set the mode property to either 'cost' or 'endpoint_constraint'. More...

std::string	getModeAsString () const
	This returns the default mode of the goal, unless the user overrode the default using setMode(). More...

Mode	getMode () const

bool	getModeIsCost () const

bool	getModeIsEndpointConstraint () const

Mode	getDefaultMode () const
	Types of goals have a class-level default for whether they are enforced as a cost or endpoint constraint. More...

bool	getSupportsEndpointConstraint () const
	Can this constraint be used in endpoint constraint mode?

const MocoConstraintInfo &	getConstraintInfo () const
	Get bounds for the constraints when using this goal in endpoint constraint mode. More...

MocoConstraintInfo &	updConstraintInfo ()

int	getNumOutputs () const
	Get the length of the return value of calcGoal().

int	getNumIntegrals () const
	Get the number of integrals required by this cost. More...

SimTK::Real	calcIntegrand (const SimTK::State &state) const
	Calculate the integrand that should be integrated and passed to calcCost(). More...

void	calcGoal (const GoalInput &input, SimTK::Vector &goal) const
	In cost mode, the returned cost includes the weight, and the elements of the returned vector should be summed by the caller to obtain the total cost. More...

void	initializeOnModel (const Model &model) const
	For use by solvers. This also performs error checks on the Problem.

void	printDescription (std::ostream &stream=std::cout) const
	Print the name type and mode of this goal. More...

Protected Member Functions
void	initializeOnModelImpl (const Model &) const override
	Perform any caching before the problem is solved. More...

void	calcIntegrandImpl (const SimTK::State &state, double &integrand) const override

void	calcGoalImpl (const GoalInput &input, SimTK::Vector &cost) const override
	The Lagrange multipliers for kinematic constraints are not available.

void	printDescriptionImpl (std::ostream &stream=std::cout) const override
	Print a more detailed description unique to each goal.

Protected Member Functions inherited from OpenSim::MocoGoal
void	setNumIntegralsAndOutputs (int numIntegrals, int numOutputs) const
	Set the number of integral terms required by this goal and the length of the vector passed into calcGoalImpl(). More...

virtual Mode	getDefaultModeImpl () const

virtual bool	getSupportsEndpointConstraintImpl () const

const Model &	getModel () const
	For use within virtual function implementations.

double	calcSystemDisplacement (const SimTK::State &initial, const SimTK::State &final) const

Additional Inherited Members
Public Types inherited from OpenSim::MocoGoal
enum	Mode { Cost, EndpointConstraint }

Member Function Documentation

◆ calcIntegrandImpl()

void OpenSim::MocoJointReactionGoal::calcIntegrandImpl	(	const SimTK::State &	state,
		double &	integrand
	)		const

overrideprotectedvirtual

Precondition(s):: The state is realized to SimTK::Stage::Position. If you need access to the controls, you must realize to Velocity:
getModel().realizeVelocity(state);
The Lagrange multipliers for kinematic constraints are not available.

Reimplemented from OpenSim::MocoGoal.

◆ initializeOnModelImpl()

void OpenSim::MocoJointReactionGoal::initializeOnModelImpl ( const Model & ) const

overrideprotectedvirtual

Perform any caching before the problem is solved.

You must override this function and invoke setNumIntegralsAndOutputs().

Precondition(s):: The model is initialized (initSystem()) and getModel() is available. The passed-in model is equivalent to getModel(). Use this opportunity to check for errors in user input.

Implements OpenSim::MocoGoal.

◆ setExpressedInFramePath()

void OpenSim::MocoJointReactionGoal::setExpressedInFramePath ( const std::string & framePath )

inline

Set the frame in which the minimized reaction load is expressed.

By default, it is set to the parent or child frame depending on the 'loads_frame' property value.

◆ setJointPath()

void OpenSim::MocoJointReactionGoal::setJointPath ( const std::string & jointPath )

inline

Set the model path to the joint whose reaction load(s) will be minimized.

◆ setLoadsFrame()

void OpenSim::MocoJointReactionGoal::setLoadsFrame ( const std::string & frame )

inline

Set the frame from which the reaction loads are computed.

Options: "parent" or "child" (default: "parent").

◆ setReactionMeasures()

void OpenSim::MocoJointReactionGoal::setReactionMeasures ( const std::vector< std::string > & measures )

inline

Set a specific set of reaction measures to be minimized.

Options: "moment-x", "moment-y", "moment-z", "force-x", "force-y", and "force-z". All reaction measures are minimized by default. Replaces the reaction measure set if it already exists.

◆ setWeight()

void OpenSim::MocoJointReactionGoal::setWeight	(	const std::string &	stateName,
		const double &	weight
	)

inline

Set the weight for an individual reaction measure.

If a weight is already set for the requested measure, then the provided weight replaces the previous weight. An exception is thrown during initialization if a weight for an unknown measure is provided.

◆ setWeightSet()

void OpenSim::MocoJointReactionGoal::setWeightSet ( const MocoWeightSet & weightSet )

inline

Provide a MocoWeightSet to weight the reaction measures in the cost.

Replaces the weight set if it already exists.

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

MocoJointReactionGoal.h

Description

Public Member Functions

Protected Member Functions

Additional Inherited Members

Member Function Documentation

◆ calcIntegrandImpl()

◆ initializeOnModelImpl()

◆ setExpressedInFramePath()

◆ setJointPath()

◆ setLoadsFrame()

◆ setReactionMeasures()

◆ setWeight()

◆ setWeightSet()