class contactConstraint

A unilateral constraint for frictionless contact between a link and a fixed surface.

Inheritance:

Public Methods

contactConstraint(void)

constructor

contactConstraint(link* L, const triple &xlink, const triple &cworld, const triple &n, double tol, part* P = NULL)

constructor.

contactConstraint(link* L, link* L2, const triple &xlink1, const triple &xlink2, const triple &n, double tol, part* P = NULL, part* P2 = NULL)

constructor.

virtual int updateConstants(const triple &xlink, const triple &cworld, const triple &n, double tol)

updates constants used in the constraint equations.

Inherited from uconstraint:

Inherited from constraint:

Public Fields

mechanism* mech

ptrList* otherMechs

linkForceRecord* frec

matrix Jc

double cDotTol

vector C

vector Cdot

int jdirty

int* _hasPosLimit

double* maxForce

double* minForce

vector prevF

int eindex

int iindex

int fdindex

int inSystem

double kp

double kv

Public Methods

inline int index(void) const

virtual int correctDrift(int i) const

inline virtual double computeCorrection(int i, int includeVel)

inline virtual int hasPosLimit(int i) const

inline virtual int hasNegLimit(int i) const

inline virtual int hasForceLimits(void) const

inline virtual void allocatePosLimits(void)

virtual void print(int printVal = 0)

virtual int createConstraintEquations(void)

virtual int deleteConstraintEquations(void)

virtual int setDynamicValues(void)

virtual const double* getCoefficients(int whichDof) const

virtual int resize(int newSize)

virtual int setDirtyFlags(void)

virtual int updateFlags(void)

inline virtual int isBilateral(void) const

inline virtual int isFrictional(int i) const

virtual int eval(int onlyConst = 0)

inline virtual double computeFStep(vector &a, vector &da, vector &f, vector &df, int i)

inline virtual double computeAStep(vector &a, vector &da, vector &f, vector &df, int i)

virtual int satisfied(const vector &a, const vector &f, int j)

inline virtual int needsImpulse(int i)

int computeJacobian(void)

virtual int violated(void)

virtual int applyToMech(mechanism* m, int subtract = 0)

int getGeneralizedForce(vector &gf)

virtual const linkForceRecord* getForces(void)

Inherited from dynoObject:

Public Fields

dynamicSystem* ds

int active

int stateSize

Public Methods

inline virtual int getState(double* state)

inline virtual int setState(const double* state)

inline virtual int reset(void)

Inherited from synObject:

Public Fields

static int staticClassID

int objectID

int verboseLevel

Public Methods

virtual const char* className(void) const

virtual synObject* copy(void) const

virtual int isOfType(int typeNum, int derivedOk)

static int setStaticClassID(void)

virtual int classID(void) const

Documentation

A unilateral constraint for frictionless contact between a link and a fixed surface. The constraint equations for a frictionless contact are:

  1.  an >= 0       (normal acceleration must be non-negative) 
  2.  fn >= 0       (normal force must be non-negative)
  3.  fn*an >= 0    (normal force and/or normal acceleration must 
 

contactConstraint(void)

constructor

contactConstraint(link* L, const triple &xlink, const triple &cworld, const triple &n, double tol, part* P = NULL)

constructor. l is the link acted on by the contact. xlink is the world-space location of contact point on the link and cworld is the world-space location of the contact point on the fixed surface. n is the surface normal at cworld and points outward from the fixed surface. tol is the tolerance on interpenetration for the contact. Ideally xlink and cworld are the same; however, since there is a depth tolerance involved, some interpenetration always occurs. cworld is thus used to compute the amount of constraint violation and corrective acceleration.

contactConstraint(link* L, link* L2, const triple &xlink1, const triple &xlink2, const triple &n, double tol, part* P = NULL, part* P2 = NULL)

constructor. l is the first link acted on by the contact, l2 is the second. xlink is the world-space location of contact point on link l and xlink2 is the world-space location of the contact point on link l2. n is the surface normal at cworld and points outward from l2 towards l1. tol is the tolerance on interpenetration for the contact. Ideally xlink and xlink2 are the same; however, since there is a depth tolerance involved, some interpenetration always occurs. The difference is used to compute the amount of constraint violation and corrective acceleration.

virtual int updateConstants(const triple &xlink, const triple &cworld, const triple &n, double tol)

updates constants used in the constraint equations. This should be called when using persistent contacts to update the constraint for changing conditions. In the case of two-link contact, cworld should be the world-space location of the contact point on the second link.

Direct child classes:

frictionContact

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