chrono::ChLinkDistance Class Reference

Description

Fixed distance constraint between two points on two ChBodyFrame objects.

The two points which are used to define the end points of the distance are assumed not to move respect to the two owner ChBody, and the amount of the distance is assumed not to change during the simulation.

#include <ChLinkDistance.h>

Inheritance diagram for chrono::ChLinkDistance:
Collaboration diagram for chrono::ChLinkDistance:

Public Types

enum  Mode { Mode::BILATERAL, Mode::UNILATERAL_MAXDISTANCE, Mode::UNILATERAL_MINDISTANCE }
 

Public Member Functions

 ChLinkDistance (const ChLinkDistance &other)
 
virtual ChLinkDistanceClone () const override
 "Virtual" copy constructor (covariant return type).
 
int Initialize (std::shared_ptr< ChBodyFrame > body1, std::shared_ptr< ChBodyFrame > body2, bool pos_are_relative, ChVector3d pos1, ChVector3d pos2, bool auto_distance=true, double mdistance=0, Mode mode=Mode::BILATERAL)
 Initialize this constraint, given the two bodies to be connected, the positions of the two anchor endpoints of the distance (each expressed in body or abs. More...
 
virtual unsigned int GetNumConstraintsBilateral () override
 Get the number of (bilateral) constraints introduced by this link.
 
virtual ChFramed GetFrame1Rel () const override
 Get the link frame 1, relative to body 1. More...
 
virtual ChFramed GetFrame2Rel () const override
 Get the link frame 2, relative to body 2. More...
 
ChVector3d GetEndPoint1Rel () const
 Get the 1st anchor endpoint for the distance (expressed in body 1 coordinate system)
 
void SetEndPoint1Rel (const ChVector3d &mset)
 Set the 1st anchor endpoint for the distance (expressed in body 1 coordinate system)
 
ChVector3d GetEndPoint1Abs () const
 Get the 1st anchor endpoint for the distance (expressed in absolute coordinate system)
 
void SetEndPoint1Abs (const ChVector3d &mset)
 Set the 1st anchor endpoint for the distance (expressed in absolute coordinate system)
 
ChVector3d GetEndPoint2Rel () const
 Get the 2nd anchor endpoint for the distance (expressed in body 2 coordinate system)
 
void SetEndPoint2Rel (const ChVector3d &mset)
 Set the 2nd anchor endpoint for the distance (expressed in body 2 coordinate system)
 
ChVector3d GetEndPoint2Abs () const
 Get the 1st anchor endpoint for the distance (expressed in absolute coordinate system)
 
void SetEndPoint2Abs (const ChVector3d &mset)
 Set the 1st anchor endpoint for the distance (expressed in absolute coordinate system)
 
void SetImposedDistance (const double mset)
 Set the imposed distance.
 
double GetImposedDistance () const
 Get the imposed distance.
 
double GetCurrentDistance () const
 Get the distance currently existing between the two endpoints.
 
void SetMode (Mode mode)
 Set link mode. More...
 
Mode GetMode () const
 Get link mode.
 
virtual ChVectorDynamic GetConstraintViolation () const override
 Get the constraint violation.
 
virtual void ArchiveOut (ChArchiveOut &archive_out) override
 Method to allow serialization of transient data to archives.
 
virtual void ArchiveIn (ChArchiveIn &archive_in) override
 Method to allow deserialization of transient data from archives. More...
 
- Public Member Functions inherited from chrono::ChPhysicsItem
 ChPhysicsItem (const ChPhysicsItem &other)
 
ChSystemGetSystem () const
 Get the pointer to the parent ChSystem().
 
virtual void SetSystem (ChSystem *m_system)
 Set the pointer to the parent ChSystem(). More...
 
void AddVisualModel (std::shared_ptr< ChVisualModel > model)
 Add an (optional) visualization model. More...
 
std::shared_ptr< ChVisualModelGetVisualModel () const
 Access the visualization model (if any). More...
 
void AddVisualShape (std::shared_ptr< ChVisualShape > shape, const ChFrame<> &frame=ChFrame<>())
 Add the specified visual shape to the visualization model. More...
 
std::shared_ptr< ChVisualShapeGetVisualShape (unsigned int i) const
 Access the specified visualization shape in the visualization model (if any). More...
 
void AddVisualShapeFEA (std::shared_ptr< ChVisualShapeFEA > shapeFEA)
 Add the specified FEA visualization object to the visualization model. More...
 
std::shared_ptr< ChVisualShapeFEAGetVisualShapeFEA (unsigned int i) const
 Access the specified FEA visualization object in the visualization model (if any). More...
 
virtual unsigned int GetNumVisualModelClones () const
 Return the number of clones of the visual model associated with this physics item. More...
 
void AddCamera (std::shared_ptr< ChCamera > camera)
 Attach a ChCamera to this physical item. More...
 
std::vector< std::shared_ptr< ChCamera > > GetCameras () const
 Get the set of cameras attached to this physics item.
 
virtual bool IsCollisionEnabled () const
 Tell if the object is subject to collision. More...
 
virtual void AddCollisionModelsToSystem (ChCollisionSystem *coll_sys) const
 Add to the provided collision system any collision models managed by this physics item. More...
 
virtual void RemoveCollisionModelsFromSystem (ChCollisionSystem *coll_sys) const
 Remove from the provided collision system any collision models managed by this physics item. More...
 
virtual void SyncCollisionModels ()
 Synchronize the position and bounding box of any collsion models managed by this physics item.
 
virtual ChAABB GetTotalAABB ()
 Get the entire AABB axis-aligned bounding box of the object. More...
 
virtual void GetCenter (ChVector3d &mcenter)
 Get a symbolic 'center' of the object. More...
 
virtual void Setup ()
 This might recompute the number of coordinates, DOFs, constraints, in case this might change (ex in ChAssembly), as well as state offsets of contained items (ex in ChMesh)
 
virtual void ForceToRest ()
 Set zero speed (and zero accelerations) in state, without changing the position. More...
 
virtual unsigned int GetNumCoordsPosLevel ()
 Get the number of coordinates at the position level. More...
 
virtual unsigned int GetNumCoordsVelLevel ()
 Get the number of coordinates at the velocity level. More...
 
virtual unsigned int GetNumConstraints ()
 Get the number of scalar constraints.
 
virtual unsigned int GetNumConstraintsUnilateral ()
 Get the number of unilateral scalar constraints.
 
unsigned int GetOffset_x ()
 Get offset in the state vector (position part)
 
unsigned int GetOffset_w ()
 Get offset in the state vector (speed part)
 
unsigned int GetOffset_L ()
 Get offset in the lagrangian multipliers.
 
void SetOffset_x (const unsigned int moff)
 Set offset in the state vector (position part) Note: only the ChSystem::Setup function should use this.
 
void SetOffset_w (const unsigned int moff)
 Set offset in the state vector (speed part) Note: only the ChSystem::Setup function should use this.
 
void SetOffset_L (const unsigned int moff)
 Set offset in the lagrangian multipliers Note: only the ChSystem::Setup function should use this.
 
virtual void IntStateGather (const unsigned int off_x, ChState &x, const unsigned int off_v, ChStateDelta &v, double &T)
 From item's state to global state vectors y={x,v} pasting the states at the specified offsets. More...
 
virtual void IntStateScatter (const unsigned int off_x, const ChState &x, const unsigned int off_v, const ChStateDelta &v, const double T, bool full_update)
 From global state vectors y={x,v} to item's state (and update) fetching the states at the specified offsets. More...
 
virtual void IntStateGatherAcceleration (const unsigned int off_a, ChStateDelta &a)
 From item's state acceleration to global acceleration vector. More...
 
virtual void IntStateScatterAcceleration (const unsigned int off_a, const ChStateDelta &a)
 From global acceleration vector to item's state acceleration. More...
 
virtual void IntStateIncrement (const unsigned int off_x, ChState &x_new, const ChState &x, const unsigned int off_v, const ChStateDelta &Dv)
 Computes x_new = x + Dt , using vectors at specified offsets. More...
 
virtual void IntStateGetIncrement (const unsigned int off_x, const ChState &x_new, const ChState &x, const unsigned int off_v, ChStateDelta &Dv)
 Computes Dt = x_new - x, using vectors at specified offsets. More...
 
virtual void IntLoadResidual_F (const unsigned int off, ChVectorDynamic<> &R, const double c)
 Takes the F force term, scale and adds to R at given offset: R += c*F. More...
 
virtual void IntLoadResidual_Mv (const unsigned int off, ChVectorDynamic<> &R, const ChVectorDynamic<> &w, const double c)
 Takes the M*v term, multiplying mass by a vector, scale and adds to R at given offset: R += c*M*w. More...
 
virtual void IntLoadLumpedMass_Md (const unsigned int off, ChVectorDynamic<> &Md, double &err, const double c)
 Adds the lumped mass to a Md vector, representing a mass diagonal matrix. More...
 
virtual void IntLoadConstraint_Ct (const unsigned int off, ChVectorDynamic<> &Qc, const double c)
 Takes the term Ct, scale and adds to Qc at given offset: Qc += c*Ct. More...
 
virtual void InjectVariables (ChSystemDescriptor &descriptor)
 Register with the given system descriptor any ChVariable objects associated with this item.
 
virtual void InjectKRMMatrices (ChSystemDescriptor &descriptor)
 Register with the given system descriptor any ChKRMBlock objects associated with this item.
 
virtual void LoadKRMMatrices (double Kfactor, double Rfactor, double Mfactor)
 Compute and load current stiffnes (K), damping (R), and mass (M) matrices in encapsulated ChKRMBlock objects. More...
 
virtual void VariablesFbReset ()
 Sets the 'fb' part (the known term) of the encapsulated ChVariables to zero.
 
virtual void VariablesFbLoadForces (double factor=1)
 Adds the current forces (applied to item) into the encapsulated ChVariables, in the 'fb' part: qf+=forces*factor.
 
virtual void VariablesQbLoadSpeed ()
 Initialize the 'qb' part of the ChVariables with the current value of speeds. More...
 
virtual void VariablesFbIncrementMq ()
 Adds M*q (masses multiplied current 'qb') to Fb, ex. More...
 
virtual void VariablesQbSetSpeed (double step=0)
 Fetches the item speed (ex. More...
 
virtual void VariablesQbIncrementPosition (double step)
 Increment item positions by the 'qb' part of the ChVariables, multiplied by a 'step' factor. More...
 
virtual void ConstraintsBiLoad_Ct (double factor=1)
 Adds the current Ct (partial t-derivative, as in C_dt=0-> [Cq]*q_dt=-Ct) to the known term (b_i) of encapsulated ChConstraints.
 
virtual void ConstraintsBiLoad_Qc (double factor=1)
 Adds the current Qc (the vector of C_dtdt=0 -> [Cq]*q_dtdt=Qc ) to the known term (b_i) of encapsulated ChConstraints.
 
virtual void ConstraintsFbLoadForces (double factor=1)
 Adds the current link-forces, if any, (caused by springs, etc.) to the 'fb' vectors of the ChVariables referenced by encapsulated ChConstraints.
 
- Public Member Functions inherited from chrono::ChObj
 ChObj (const ChObj &other)
 
int GetIdentifier () const
 Get the unique integer identifier of this object. More...
 
void SetTag (int tag)
 Set an object integer tag (default: -1). More...
 
int GetTag () const
 Get the tag of this object.
 
void SetName (const std::string &myname)
 Set the name of this object.
 
const std::string & GetName () const
 Get the name of this object.
 
double GetChTime () const
 Gets the simulation time of this object.
 
void SetChTime (double m_time)
 Sets the simulation time of this object.
 
virtual std::string & ArchiveContainerName ()
 

Additional Inherited Members

- Protected Member Functions inherited from chrono::ChObj
int GenerateUniqueIdentifier ()
 
- Protected Attributes inherited from chrono::ChPhysicsItem
ChSystemsystem
 parent system
 
std::shared_ptr< ChVisualModelInstancevis_model_instance
 instantiated visualization model
 
std::vector< std::shared_ptr< ChCamera > > cameras
 set of cameras
 
unsigned int offset_x
 offset in vector of state (position part)
 
unsigned int offset_w
 offset in vector of state (speed part)
 
unsigned int offset_L
 offset in vector of lagrangian multipliers
 
- Protected Attributes inherited from chrono::ChObj
double ChTime
 object simulation time
 
std::string m_name
 object name
 
int m_identifier
 object unique identifier
 
int m_tag
 user-supplied tag
 

Member Enumeration Documentation

◆ Mode

Enumerator
BILATERAL 

bilateral joint

UNILATERAL_MAXDISTANCE 

unilateral, imposed max distance, current <= imposed

UNILATERAL_MINDISTANCE 

unilateral, imposed min distance, current >= imposed

Member Function Documentation

◆ ArchiveIn()

void chrono::ChLinkDistance::ArchiveIn ( ChArchiveIn archive_in)
overridevirtual

Method to allow deserialization of transient data from archives.

Method to allow de serialization of transient data from archives.

Reimplemented from chrono::ChLink.

◆ GetFrame1Rel()

virtual ChFramed chrono::ChLinkDistance::GetFrame1Rel ( ) const
inlineoverridevirtual

Get the link frame 1, relative to body 1.

For this class link frame 1 coincides with body 1.

Implements chrono::ChLink.

◆ GetFrame2Rel()

ChFramed chrono::ChLinkDistance::GetFrame2Rel ( ) const
inlineoverridevirtual

Get the link frame 2, relative to body 2.

For this class link frame 2 is located at body 2, but with the X axes pointing towards body 1.

Implements chrono::ChLink.

◆ Initialize()

int chrono::ChLinkDistance::Initialize ( std::shared_ptr< ChBodyFrame body1,
std::shared_ptr< ChBodyFrame body2,
bool  pos_are_relative,
ChVector3d  pos1,
ChVector3d  pos2,
bool  auto_distance = true,
double  mdistance = 0,
Mode  mode = Mode::BILATERAL 
)

Initialize this constraint, given the two bodies to be connected, the positions of the two anchor endpoints of the distance (each expressed in body or abs.

coordinates) and the imposed distance.

Parameters
body1first frame to link
body2second frame to link
pos_are_relativetrue: following pos. are relative to bodies
pos1pos. of distance endpoint, for 1st body (rel. or abs., see flag above)
pos2pos. of distance endpoint, for 2nd body (rel. or abs., see flag above)
auto_distanceif true, initializes the imposed distance as the distance between pos1 and pos2
mdistanceimposed distance (no need to define, if auto_distance=true.)
modeset distance constraining mode

◆ SetMode()

void chrono::ChLinkDistance::SetMode ( Mode  mode)

Set link mode.

The joint can act as bilateral or unilateral; in this latter case, it can either limit the maximum or minimum distance; if in unilateral mode, a VI solver is required!


The documentation for this class was generated from the following files:
  • /builds/uwsbel/chrono/src/chrono/physics/ChLinkDistance.h
  • /builds/uwsbel/chrono/src/chrono/physics/ChLinkDistance.cpp