This subsystem tracks the paths of massless, frictionless cables that take the shortest route between two distant points of a multibody system, passing smoothly over geometric obstacles that are attached to intermediate bodies. More...

#include <CableTrackerSubsystem.h>

Inheritance diagram for SimTK::CableTrackerSubsystem:

Public Member Functions
	CableTrackerSubsystem ()

	CableTrackerSubsystem (MultibodySystem &)

int	getNumCablePaths () const
	Get the number of cable paths being managed by this cable tracker subsystem. More...

const CablePath &	getCablePath (CablePathIndex cableIx) const
	Get const access to a particular cable path. More...

CablePath &	updCablePath (CablePathIndex cableIx)
	Get writable access to a particular cable path. More...

Public Member Functions inherited from SimTK::Subsystem
	Subsystem ()

	Subsystem (const Subsystem &)

Subsystem &	operator= (const Subsystem &)

	~Subsystem ()

const String &	getName () const

const String &	getVersion () const

QIndex	allocateQ (State &, const Vector &qInit) const

UIndex	allocateU (State &, const Vector &uInit) const

ZIndex	allocateZ (State &, const Vector &zInit) const

DiscreteVariableIndex	allocateDiscreteVariable (State &, Stage invalidates, AbstractValue *v) const

DiscreteVariableIndex	allocateAutoUpdateDiscreteVariable (State &, Stage invalidates, AbstractValue *v, Stage updateDependsOn) const

CacheEntryIndex	allocateCacheEntry (const State &, Stage dependsOn, Stage computedBy, AbstractValue *v) const

CacheEntryIndex	allocateCacheEntry (const State &state, Stage g, AbstractValue *v) const

CacheEntryIndex	allocateLazyCacheEntry (const State &state, Stage earliest, AbstractValue *v) const

QErrIndex	allocateQErr (const State &, int nqerr) const

UErrIndex	allocateUErr (const State &, int nuerr) const

UDotErrIndex	allocateUDotErr (const State &, int nudoterr) const

EventTriggerByStageIndex	allocateEventTriggersByStage (const State &, Stage, int ntriggers) const

const Vector &	getQ (const State &) const

const Vector &	getU (const State &) const

const Vector &	getZ (const State &) const

const Vector &	getQDot (const State &) const

const Vector &	getUDot (const State &) const

const Vector &	getZDot (const State &) const

const Vector &	getQDotDot (const State &) const

const Vector &	getQErr (const State &) const

const Vector &	getUErr (const State &) const

const Vector &	getUDotErr (const State &) const

const Vector &	getMultipliers (const State &) const

const Vector &	getEventTriggersByStage (const State &, Stage) const

Vector &	updQ (State &) const

Vector &	updU (State &) const

Vector &	updZ (State &) const

void	setQ (State &s, const Vector &q) const

void	setU (State &s, const Vector &u) const

void	setZ (State &s, const Vector &z) const

Vector &	updQDot (const State &) const

Vector &	updUDot (const State &) const

Vector &	updZDot (const State &) const

Vector &	updQDotDot (const State &) const

Vector &	updQErr (const State &) const

Vector &	updUErr (const State &) const

Vector &	updUDotErr (const State &) const

Vector &	updMultipliers (const State &) const

Vector &	updEventTriggersByStage (const State &, Stage) const

Stage	getStage (const State &) const

const AbstractValue &	getDiscreteVariable (const State &s, DiscreteVariableIndex dx) const

Real	getDiscreteVarLastUpdateTime (const State &s, DiscreteVariableIndex dx) const

CacheEntryIndex	getDiscreteVarUpdateIndex (const State &s, DiscreteVariableIndex dx) const

const AbstractValue &	getDiscreteVarUpdateValue (const State &s, DiscreteVariableIndex dx) const

AbstractValue &	updDiscreteVarUpdateValue (const State &s, DiscreteVariableIndex dx) const

bool	isDiscreteVarUpdateValueRealized (const State &s, DiscreteVariableIndex dx) const

void	markDiscreteVarUpdateValueRealized (const State &s, DiscreteVariableIndex dx) const

AbstractValue &	updDiscreteVariable (State &, DiscreteVariableIndex) const

const AbstractValue &	getCacheEntry (const State &, CacheEntryIndex) const

AbstractValue &	updCacheEntry (const State &, CacheEntryIndex) const

bool	isCacheValueRealized (const State &, CacheEntryIndex) const

void	markCacheValueRealized (const State &, CacheEntryIndex) const

void	markCacheValueNotRealized (const State &, CacheEntryIndex) const

SystemQIndex	getQStart (const State &) const

int	getNQ (const State &) const

SystemUIndex	getUStart (const State &) const

int	getNU (const State &) const

SystemZIndex	getZStart (const State &) const

int	getNZ (const State &) const

SystemQErrIndex	getQErrStart (const State &) const

int	getNQErr (const State &) const

SystemUErrIndex	getUErrStart (const State &) const

int	getNUErr (const State &) const

SystemUDotErrIndex	getUDotErrStart (const State &) const

int	getNUDotErr (const State &) const

SystemMultiplierIndex	getMultipliersStart (const State &) const

int	getNMultipliers (const State &) const

SystemEventTriggerByStageIndex	getEventTriggerStartByStage (const State &, Stage) const

int	getNEventTriggersByStage (const State &, Stage) const

bool	isInSystem () const

bool	isInSameSystem (const Subsystem &otherSubsystem) const

const System &	getSystem () const

System &	updSystem ()

SubsystemIndex	getMySubsystemIndex () const

bool	isOwnerHandle () const

bool	isEmptyHandle () const

bool	isSameSubsystem (const Subsystem &otherSubsystem) const

bool	subsystemTopologyHasBeenRealized () const

void	invalidateSubsystemTopologyCache () const

MeasureIndex	adoptMeasure (AbstractMeasure &)

AbstractMeasure	getMeasure (MeasureIndex) const

template<class T >
Measure_< T >	getMeasure_ (MeasureIndex mx) const

const Subsystem::Guts &	getSubsystemGuts () const

Subsystem::Guts &	updSubsystemGuts ()

void	adoptSubsystemGuts (Subsystem::Guts *g)

void	setSystem (System &, SubsystemIndex)

	Subsystem (Subsystem::Guts *g)

bool	hasGuts () const

Detailed Description

This subsystem tracks the paths of massless, frictionless cables that take the shortest route between two distant points of a multibody system, passing smoothly over geometric obstacles that are attached to intermediate bodies.

The calculated path will consist of a series of straight line segments between obstacles, and geodesics over the obstacles.

Force elements defined elsewhere may make use of cable paths to apply forces to the system, by calculating a uniform tension in the cable that may depend on the cable kinematics calculated here. Cable kinematics includes the path, the cable length, and the cable "rate", defined as the time derivative of length. The path and length are available at Position stage, the rate is available at Velocity stage.

During construction, one or more CablePath objects are defined by giving for each CablePath an origin and end point and an ordered set of geometric obstacles represented either by surfaces or "via" points. Via points are like frictionless eyelets that the cable must pass through and can generate forces in any direction perpendicular to the cable; surfaces are one-sided and can only apply positive forces to the cable. Thus the cable path does not necessarily touch all the obstacles; the obstacles that it does touch are called the "active" obstacles. Via points are always active.

Every obstacle and point is rigidly fixed to Ground or some moving body of the multibody system, with its pose or station point provided. Any number of obstacles may be placed on one body.

Constructor & Destructor Documentation

SimTK::CableTrackerSubsystem::CableTrackerSubsystem ( )

SimTK::CableTrackerSubsystem::CableTrackerSubsystem ( MultibodySystem & )

explicit

Member Function Documentation

int SimTK::CableTrackerSubsystem::getNumCablePaths ( ) const

Get the number of cable paths being managed by this cable tracker subsystem.

These are identified by CablePathIndex values from 0 to getNumCablePaths()-1. This is available after realizeTopology() and does not change subsequently.

const CablePath& SimTK::CableTrackerSubsystem::getCablePath ( CablePathIndex cableIx ) const

Get const access to a particular cable path.

CablePath& SimTK::CableTrackerSubsystem::updCablePath ( CablePathIndex cableIx )

Get writable access to a particular cable path.

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

CableTrackerSubsystem.h

Public Member Functions

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation