Description

Generic mate constraint.

This class allows selecting the DOFs to be constrained.

#include <ChLinkMate.h>

Inheritance diagram for chrono::ChLinkMateGeneric:
Collaboration diagram for chrono::ChLinkMateGeneric:

Public Types

using ChConstraintVectorX = Eigen::Matrix< double, Eigen::Dynamic, 1, Eigen::ColMajor, 6, 1 >
 

Public Member Functions

 ChLinkMateGeneric (bool mc_x=true, bool mc_y=true, bool mc_z=true, bool mc_rx=true, bool mc_ry=true, bool mc_rz=true)
 
 ChLinkMateGeneric (const ChLinkMateGeneric &other)
 
virtual ChLinkMateGenericClone () const override
 "Virtual" copy constructor (covariant return type).
 
virtual ChFrame GetVisualModelFrame (unsigned int nclone=0) const override
 Get the reference frame (expressed in and relative to the absolute frame) of the visual model. More...
 
virtual ChFramed GetFrame1Rel () const override
 Get the link frame 1, relative to body 1.
 
virtual ChFramed GetFrame2Rel () const override
 Get the link frame 2, relative to body 2.
 
bool IsConstrainedX () const
 
bool IsConstrainedY () const
 
bool IsConstrainedZ () const
 
bool IsConstrainedRx () const
 
bool IsConstrainedRy () const
 
bool IsConstrainedRz () const
 
void SetConstrainedCoords (bool mc_x, bool mc_y, bool mc_z, bool mc_rx, bool mc_ry, bool mc_rz)
 Sets which movements (of frame 1 respect to frame 2) are constrained.
 
virtual void Initialize (std::shared_ptr< ChBodyFrame > body1, std::shared_ptr< ChBodyFrame > body2, ChFrame<> absframe)
 Initialize the link given the two bodies to be connected and the absolute position of the link. More...
 
virtual void Initialize (std::shared_ptr< ChBodyFrame > body1, std::shared_ptr< ChBodyFrame > body2, bool pos_are_relative, ChFrame<> frame1, ChFrame<> frame2)
 Initialize the link given the two bodies to be connected and two frames (either referring to absolute or body coordinates) in which the link must be placed. More...
 
virtual void Initialize (std::shared_ptr< ChBodyFrame > body1, std::shared_ptr< ChBodyFrame > body2, bool pos_are_relative, const ChVector3d &point1, const ChVector3d &point2, const ChVector3d &dir1, const ChVector3d &dir2)
 Initialization based on passing two vectors (point + dir) on the two bodies, which will represent the Z axes of the two frames (X and Y will be built from the Z vector via Gram-Schmidt orthonormalization). More...
 
virtual void SetDisabled (bool mdis) override
 Enable/disable all the constraint of the link as desired.
 
virtual void SetBroken (bool mon) override
 Set this link as 'broken'.
 
void SetUseTangentStiffness (bool useKc)
 Enable/disable calculation of the tangent stiffness matrix (Kc) of this constraint (default: false).
 
virtual unsigned int GetNumConstraints () override
 Get the number of scalar constraints.
 
virtual unsigned int GetNumConstraintsBilateral () override
 Get the number of bilateral scalar constraints.
 
virtual unsigned int GetNumConstraintsUnilateral () override
 Get the number of unilateral scalar constraints.
 
virtual ChVectorDynamic GetConstraintViolation () const override
 Link violation (residuals of the link constraint equations).
 
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...
 
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 InjectVariables (ChSystemDescriptor &descriptor)
 Register with the given system descriptor any ChVariable objects associated with this item.
 
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_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 ()
 

Protected Member Functions

void SetupLinkMask ()
 
void ChangedLinkMask ()
 
virtual void Update (double mtime, bool update_assets=true) override
 Update link state, constraint Jacobian, and frames. More...
 
virtual void IntStateGatherReactions (const unsigned int off_L, ChVectorDynamic<> &L) override
 From item's reaction forces to global reaction vector. More...
 
virtual void IntStateScatterReactions (const unsigned int off_L, const ChVectorDynamic<> &L) override
 From global reaction vector to item's reaction forces. More...
 
virtual void IntLoadResidual_CqL (const unsigned int off_L, ChVectorDynamic<> &R, const ChVectorDynamic<> &L, const double c) override
 Takes the term Cq'*L, scale and adds to R at given offset: R += c*Cq'*L. More...
 
virtual void IntLoadConstraint_C (const unsigned int off, ChVectorDynamic<> &Qc, const double c, bool do_clamp, double recovery_clamp) override
 Takes the term C, scale and adds to Qc at given offset: Qc += c*C. More...
 
virtual void IntLoadConstraint_Ct (const unsigned int off, ChVectorDynamic<> &Qc, const double c) override
 Takes the term Ct, scale and adds to Qc at given offset: Qc += c*Ct. More...
 
virtual void IntToDescriptor (const unsigned int off_v, const ChStateDelta &v, const ChVectorDynamic<> &R, const unsigned int off_L, const ChVectorDynamic<> &L, const ChVectorDynamic<> &Qc) override
 Prepare variables and constraints to accommodate a solution: More...
 
virtual void IntFromDescriptor (const unsigned int off_v, ChStateDelta &v, const unsigned int off_L, ChVectorDynamic<> &L) override
 After a solver solution, fetch values from variables and constraints into vectors: More...
 
virtual void InjectConstraints (ChSystemDescriptor &descriptor) override
 Register with the given system descriptor any ChConstraint objects associated with this item.
 
virtual void ConstraintsBiReset () override
 Sets to zero the known term (b_i) of encapsulated ChConstraints.
 
virtual void ConstraintsBiLoad_C (double factor=1, double recovery_clamp=0.1, bool do_clamp=false) override
 Adds the current C (constraint violation) to the known term (b_i) of encapsulated ChConstraints.
 
virtual void ConstraintsBiLoad_Ct (double factor=1) override
 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 LoadConstraintJacobians () override
 Compute and load current Jacobians in encapsulated ChConstraint objects.
 
virtual void ConstraintsFetch_react (double factor=1) override
 Fetches the reactions from the lagrangian multiplier (l_i) of encapsulated ChConstraints. More...
 
virtual void InjectKRMMatrices (ChSystemDescriptor &descriptor) override
 Register with the given system descriptor any ChKRMBlock objects associated with this item.
 
virtual void LoadKRMMatrices (double Kfactor, double Rfactor, double Mfactor) override
 Add the current stiffness K matrix in encapsulated ChKRMBlock item(s), if any. More...
 
- Protected Member Functions inherited from chrono::ChObj
int GenerateUniqueIdentifier ()
 

Protected Attributes

ChFrame frame1
 
ChFrame frame2
 
bool c_x
 
bool c_y
 
bool c_z
 
bool c_rx
 
bool c_ry
 
bool c_rz
 
int m_num_constr
 number of constraints
 
int m_num_constr_bil
 number of bilateral constraints
 
int m_num_constr_uni
 number of unilateral constraints
 
ChLinkMask mask
 
ChConstraintVectorX C
 residuals
 
ChMatrix33 P
 projection matrix from Lagrange multiplier to reaction torque
 
ChVector3d gamma_f
 translational Lagrange multipliers
 
ChVector3d gamma_m
 rotational Lagrange multipliers
 
std::unique_ptr< ChKRMBlockKmatr = nullptr
 the tangent stiffness matrix of constraint
 
- 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 Function Documentation

◆ ArchiveIn()

◆ ConstraintsFetch_react()

void chrono::ChLinkMateGeneric::ConstraintsFetch_react ( double  factor = 1)
overrideprotectedvirtual

Fetches the reactions from the lagrangian multiplier (l_i) of encapsulated ChConstraints.

Mostly used after the solver provided the solution in ChConstraints. Also, should convert the reactions obtained from dynamical simulation, from link space to intuitive react_force and react_torque.

Reimplemented from chrono::ChPhysicsItem.

◆ GetVisualModelFrame()

virtual ChFrame chrono::ChLinkMateGeneric::GetVisualModelFrame ( unsigned int  nclone = 0) const
inlineoverridevirtual

Get the reference frame (expressed in and relative to the absolute frame) of the visual model.

For a ChLinkMate, this returns the absolute coordinate system of the second body.

Reimplemented from chrono::ChLinkBase.

◆ Initialize() [1/3]

void chrono::ChLinkMateGeneric::Initialize ( std::shared_ptr< ChBodyFrame body1,
std::shared_ptr< ChBodyFrame body2,
bool  pos_are_relative,
ChFrame<>  frame1,
ChFrame<>  frame2 
)
virtual

Initialize the link given the two bodies to be connected and two frames (either referring to absolute or body coordinates) in which the link must be placed.

It is recommended to place the bodies so that the constraints are satisfied. Starting the simulation with constraints violation might lead to unstable results.

Parameters
body1first body to link
body2second body to link
pos_are_relativetrue: following pos. are relative to bodies
frame1slave frame 1 (rel. or abs.)
frame2master frame 2 (rel. or abs.)

Reimplemented in chrono::ChLinkMotorLinearDriveline, and chrono::ChLinkMotorRotationDriveline.

◆ Initialize() [2/3]

void chrono::ChLinkMateGeneric::Initialize ( std::shared_ptr< ChBodyFrame body1,
std::shared_ptr< ChBodyFrame body2,
bool  pos_are_relative,
const ChVector3d point1,
const ChVector3d point2,
const ChVector3d dir1,
const ChVector3d dir2 
)
virtual

Initialization based on passing two vectors (point + dir) on the two bodies, which will represent the Z axes of the two frames (X and Y will be built from the Z vector via Gram-Schmidt orthonormalization).

It is recommended to place the bodies so that the constraints are satisfied. Starting the simulation with constraints violation might lead to unstable results.

Parameters
body1first body to link
body2second body to link
pos_are_relativetrue: following pos. are relative to bodies
point1origin of slave frame 1 (rel. or abs.)
point2origin of master frame 2 (rel. or abs.)
dir1X axis of slave plane 1 (rel. or abs.)
dir2X axis of master plane 2 (rel. or abs.)

Reimplemented in chrono::ChLinkMotorLinearDriveline, chrono::ChLinkMotorRotationDriveline, chrono::ChLinkMatePlanar, chrono::ChLinkMateOrthogonal, chrono::ChLinkMateParallel, chrono::ChLinkMatePrismatic, chrono::ChLinkMateRevolute, and chrono::ChLinkMateCylindrical.

◆ Initialize() [3/3]

void chrono::ChLinkMateGeneric::Initialize ( std::shared_ptr< ChBodyFrame body1,
std::shared_ptr< ChBodyFrame body2,
ChFrame<>  absframe 
)
virtual

Initialize the link given the two bodies to be connected and the absolute position of the link.

Two frames, moving together with each of the two bodies, will be automatically created. This method guarantees that the constraint is satisfied, given that the bodies will not be moved before the simulation starts.

Parameters
body1first body to link
body2second body to link
absframelink frame, in abs. coordinate

Reimplemented in chrono::ChLinkMotorLinearDriveline, and chrono::ChLinkMotorRotationDriveline.

◆ IntFromDescriptor()

void chrono::ChLinkMateGeneric::IntFromDescriptor ( const unsigned int  off_v,
ChStateDelta v,
const unsigned int  off_L,
ChVectorDynamic<> &  L 
)
overrideprotectedvirtual

After a solver solution, fetch values from variables and constraints into vectors:

Parameters
off_voffset for v
vvector to where the q 'unknowns' term of the variables will be copied
off_Loffset for L
Lvector to where L 'lagrangian ' term of the constraints will be copied

Reimplemented from chrono::ChPhysicsItem.

◆ IntLoadConstraint_C()

void chrono::ChLinkMateGeneric::IntLoadConstraint_C ( const unsigned int  off,
ChVectorDynamic<> &  Qc,
const double  c,
bool  do_clamp,
double  recovery_clamp 
)
overrideprotectedvirtual

Takes the term C, scale and adds to Qc at given offset: Qc += c*C.

Parameters
offoffset in Qc residual
Qcresult: the Qc residual, Qc += c*C
ca scaling factor
do_clampapply clamping to c*C?
recovery_clampvalue for min/max clamping of c*C

Reimplemented from chrono::ChPhysicsItem.

◆ IntLoadConstraint_Ct()

void chrono::ChLinkMateGeneric::IntLoadConstraint_Ct ( const unsigned int  off,
ChVectorDynamic<> &  Qc,
const double  c 
)
overrideprotectedvirtual

Takes the term Ct, scale and adds to Qc at given offset: Qc += c*Ct.

Parameters
offoffset in Qc residual
Qcresult: the Qc residual, Qc += c*Ct
ca scaling factor

Reimplemented from chrono::ChPhysicsItem.

◆ IntLoadResidual_CqL()

void chrono::ChLinkMateGeneric::IntLoadResidual_CqL ( const unsigned int  off_L,
ChVectorDynamic<> &  R,
const ChVectorDynamic<> &  L,
const double  c 
)
overrideprotectedvirtual

Takes the term Cq'*L, scale and adds to R at given offset: R += c*Cq'*L.

Parameters
off_Loffset in L multipliers
Rresult: the R residual, R += c*Cq'*L
Lthe L vector
ca scaling factor

Reimplemented from chrono::ChPhysicsItem.

◆ IntStateGatherReactions()

void chrono::ChLinkMateGeneric::IntStateGatherReactions ( const unsigned int  off_L,
ChVectorDynamic<> &  L 
)
overrideprotectedvirtual

From item's reaction forces to global reaction vector.

Parameters
off_Loffset in L vector
LL vector of reaction forces

Reimplemented from chrono::ChPhysicsItem.

◆ IntStateScatterReactions()

void chrono::ChLinkMateGeneric::IntStateScatterReactions ( const unsigned int  off_L,
const ChVectorDynamic<> &  L 
)
overrideprotectedvirtual

From global reaction vector to item's reaction forces.

Parameters
off_Loffset in L vector
LL vector of reaction forces

Reimplemented from chrono::ChPhysicsItem.

◆ IntToDescriptor()

void chrono::ChLinkMateGeneric::IntToDescriptor ( const unsigned int  off_v,
const ChStateDelta v,
const ChVectorDynamic<> &  R,
const unsigned int  off_L,
const ChVectorDynamic<> &  L,
const ChVectorDynamic<> &  Qc 
)
overrideprotectedvirtual

Prepare variables and constraints to accommodate a solution:

Parameters
off_voffset for v and R
vvector copied into the q 'unknowns' term of the variables
Rvector copied into the F 'force' term of the variables
off_Loffset for L and Qc
Lvector copied into the L 'lagrangian ' term of the constraints
Qcvector copied into the Qb 'constraint' term of the constraints

Reimplemented from chrono::ChPhysicsItem.

◆ LoadKRMMatrices()

void chrono::ChLinkMateGeneric::LoadKRMMatrices ( double  Kfactor,
double  Rfactor,
double  Mfactor 
)
overrideprotectedvirtual

Add the current stiffness K matrix in encapsulated ChKRMBlock item(s), if any.

The K matrix is loaded with scaling value Kfactor.

Reimplemented from chrono::ChPhysicsItem.

Reimplemented in chrono::ChLinkMotionImposed, and chrono::ChLinkMotorRotationAngle.

◆ Update()

void chrono::ChLinkMateGeneric::Update ( double  mtime,
bool  update_assets = true 
)
overrideprotectedvirtual

Update link state, constraint Jacobian, and frames.

This is called automatically by the solver at each time step. Derived classes must call this parent method and then take care of updating their own assets.

Reimplemented from chrono::ChLink.

Reimplemented in chrono::ChLinkMatePlanar, chrono::ChLinkMotorRotation, chrono::ChLinkMotorLinear, chrono::ChLinkMotor, chrono::ChLinkMateOrthogonal, and chrono::ChLinkMateDistanceZ.


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