OpenSim::ActuatorForceTarget Class Reference

A Computed Muscle Control (CMC) optimization target for controlling dynamic systems whose actuators may be themselves governed by differential equations, meaning there may be non-linear behavior and delays in force production. More...

#include <ActuatorForceTarget.h>

Inheritance diagram for OpenSim::ActuatorForceTarget:

List of all members.

Public Member Functions
virtual	~ActuatorForceTarget ()
	Destructor.
	ActuatorForceTarget (int aNX, CMC *aController)
	Constructor.
void	setStressTermWeight (double aWeight)
	Set the weight of the actuator force stress term in the performance criterion.
bool	prepareToOptimize (SimTK::State &s, double *x)
int	objectiveFunc (const SimTK::Vector &aF, const bool new_coefficients, SimTK::Real &rP) const
int	gradientFunc (const SimTK::Vector &x, const bool new_coefficients, SimTK::Vector &gradient) const

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Detailed Description

A Computed Muscle Control (CMC) optimization target for controlling dynamic systems whose actuators may be themselves governed by differential equations, meaning there may be non-linear behavior and delays in force production.

The performance criterion is a sum of two terms. The first term is the sum of actutor stresses squared. The second term is a weighted sum of terms designed to achieve a set of desired accelerations that will drive the dynamic model toward a set of target kinematic trajectories. The desired accelerations are according to the Proportional Derivative (PD) control law.

Because the performance criterion is simply a long sum of things, achieving the desired accelerations can be compromised in order to reduce the forces (or moments) applied by the actutors. This feature is what is exploited by the Residual Reduction Algorithm.

Although this target is fairly robust (meaning the optimizer should not fail to find a solution), it is a bit slower and less accurate than the "fast" target

See also:

ActuatorForceTargetFast.

Version:

1.0

Author:

Frank C. Anderson

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Constructor & Destructor Documentation

ActuatorForceTarget::~ActuatorForceTarget

(

)

[virtual]

Destructor.

ActuatorForceTarget::ActuatorForceTarget	(	int	aNX,
		CMC *	aController
	)

Constructor.

Parameters:

	aNX	Number of controls.
	aController	Parent controller.

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Member Function Documentation

int OpenSim::ActuatorForceTarget::gradientFunc	(	const SimTK::Vector &	x,
		const bool	new_coefficients,
		SimTK::Vector &	gradient
	)			const

int OpenSim::ActuatorForceTarget::objectiveFunc	(	const SimTK::Vector &	aF,
		const bool	new_coefficients,
		SimTK::Real &	rP
	)			const

bool ActuatorForceTarget::prepareToOptimize	(	SimTK::State &	s,
		double *	x
	)			[virtual]

Reimplemented from OpenSim::OptimizationTarget.

void ActuatorForceTarget::setStressTermWeight

(

double

aWeight

)

Set the weight of the actuator force stress term in the performance criterion.

Parameters:

aWeight

Weight premultiplying the sum squared stresses.

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

• OpenSim/Tools/ActuatorForceTarget.h
• OpenSim/Tools/ActuatorForceTarget.cpp