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suDecompTaylor Class Reference

A class for computing induced reaction forces using the "perturbed integration" methodology. More...

#include <suDecompTaylor.h>

Inheritance diagram for suDecompTaylor:

List of all members.

Public Member Functions
	suDecompTaylor (rdModel *aModel)
	Construct an object for performing a reaction force decomposition analysis.
virtual	~suDecompTaylor ()
	Destructor.
virtual void	compute (double *aXPrev, double *aYPrev, int aStep, double aDT, double aT, double *aX, double *aY)
	Compute the reaction force decomposition using Taylor expansion.
virtual void	applyActionForce (int aC, double aT, double *aX, double *aY)
	Apply appropriate action force.
virtual void	initializeForceElements ()
	Initialize the force values for the component elements.
virtual void	initializeVelocityElements ()
	Initialize the velocities values for the component elements.
virtual void	computeFrictionFactors (double aT, double *aX, double *aY)
	Compute the factors for accounting for reductions in the contact force made to enforce frictional constraints.
virtual void	computeHigherOrderDerivatives (int c, double t, double *dudt, double *ddudt, double *dddudt)
	Compute higher order derivatives of the accelerations of the generalized coordinates.
virtual void	computeContactVelocities (double *rVels)
	Compute the velocities of all contact points expressed in the reference frame of BodyA.
virtual void	computeContactForces (double *rFrcs)
	Compute the force applied to BodyB expressed in the frame of BodyA for all contact points.
virtual int	begin (int aStep, double aDT, double aT, double *aX, double *aY, void *aClientData=NULL)
	At the beginning of an integration, initialize the decomposition.
Protected Attributes
bool *	_contactJustEstablished
	Flag to indicate that contact has just been established.
double *	_v
	Induced contact point velocities.
double *	_a
	Induced contact point accelerations.
double *	_fp
	Component forces due to position changes.
double *	_fv
	Component forces due to velocity changes.
double *	_at
	Array for holding history of acceleration times.
double *	_ah
	Array for holding acceleration histories.
double *	_yTmp
	Internal work array for holding the states.
double *	_xTmp
	Internal work array for holding the controls.
double *	_qPrev
	Internal work array for the generalized coordinates of the previous time step.
double *	_uPrev
	Internal work array for the generalized speeds of the previous time step.
double *	_q
	Internal work array for the generalized coordinates.
double *	_u
	Internal work array for the generalized speeds.
double *	_dqdt
	Internal work array for the time derivative of the generalized coordinates.
double *	_dudt
	Internal work array for the time derivative of the generalized speeds.
double *	_ddudt
	Internal work array for the 2nd time derivative of the generalized speeds.
double *	_dddudt
	Internal work array for the 3rd time derivative of the generalized speeds.
double *	_du
	Internal work array for the change in generalized speeds.
double *	_pa
	Current contact points.
double *	_paPrev
	Contact points prior to fricitonal sliding.
double *	_svel
	Current contact velocities.
double *	_sfrc
	Current contact forces.
double *	_pfrc
	Current contact forces due to elastic terms.
double *	_dfpFric
	Frictional change in conatct force due to sliding of spring setpoints.
double *	_dfvFric
	Frictional change in conatct force against damping forces.
double *	_pAlpha
	Array used to adjust for changes in elastic contact forces due to sliding of spring setpoints.
double *	_vAlpha
	Array used to adjust for changes in viscous contact forces due to enforcement of friction constraints.
double *	_J
	Translational Jacobian.
double *	_JPrev
	Previous translational Jacobian.
double *	_JDiff
	Difference between previous and curent Jacobians.
Private Member Functions
void	setNull ()
	Set member variables to approprate NULL values.
void	constructManager ()
void	constructContactAnalysis ()
void	constructDescription ()
	Construct a description.
void	updateStorageDescriptions ()
	Update storage descriptions.
void	allocate ()
	Allocate memory.

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Detailed Description

A class for computing induced reaction forces using the "perturbed integration" methodology.

Author:

Frank C. Anderson

Version:

1.0

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Constructor & Destructor Documentation

suDecompTaylor::suDecompTaylor (  rdModel *  aModel  )

Construct an object for performing a reaction force decomposition analysis. The decomposition is performed using the perturbed integration method. It is critical that a twin or copy of the model used to conduct the nominal simulation be used to construct this decomposition analysis. If the nominal simulation model is used, this analysis may change the trajectory of the simulation because model states and contact setpoints are altered during the analysis. Parameters: aManager  Simulation manager of the nominal simulation. aContact  Contact analysis of the nominal simulation. aModelTwin  Twin of the model used to conduct the nominal simulation. aDT  Perturbed integration time window in real time. aDF  Force perturbation. See also: setIntegrationWindow() setPerturbation()

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Member Function Documentation

void suDecompTaylor::computeContactForces (  double *  rFrcs  )  [virtual]

Compute the force applied to BodyB expressed in the frame of BodyA for all contact points. Prior to calling this method, the model states must be set and rdModel::computeContact() should be called. Parameters: rForces  Forces of contact points arranged as follows: rForces[point index][3], so the dimension of rForces should be np*3.

void suDecompTaylor::computeContactVelocities (  double *  rVels  )  [virtual]

Compute the velocities of all contact points expressed in the reference frame of BodyA. Prior to calling this method, the model states must be set and rdModel::computeContact() should be called. Parameters: rVels  Velocities of contact points arranged as follows: rVels[point index][3], so the dimension of rVels should be np*3.

void suDecompTaylor::computeFrictionFactors (  double  aT, double *  aX, double *  aY )  [virtual]

Compute the factors for accounting for reductions in the contact force made to enforce frictional constraints. Parameters: aT  Time. aX  Controls. aY  States. Todo: Account for changes in the contact point on BodyB.

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

• suDecompTaylor.h
• suDecompTaylor.cpp

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