chrono::ChLinkTSDA Class Reference

Description

Class for translational spring-damper-actuator (TSDA) with the force optionally specified through a functor object (default, linear TSDA).

Optionally, a ChLinkTSDA can have internal dynamics, described by a system of ODEs. The internal states are integrated simultaneous with the containing system and they can be accessed and used in the force calculation. ChLinkTSDA provides optional support for computing Jacobians of the generalized forces.

#include <ChLinkTSDA.h>

Inheritance diagram for chrono::ChLinkTSDA:
Collaboration diagram for chrono::ChLinkTSDA:

Classes

class  ForceFunctor
 Class to be used as a callback interface for calculating the general spring-damper force. More...
 
class  ODE
 Class to be used as a callback interface for specifying the ODE, y' = f(t,y); y(0) = y0. More...
 

Public Member Functions

 ChLinkTSDA (const ChLinkTSDA &other)
 
virtual ChLinkTSDAClone () const override
 "Virtual" copy constructor (covariant return type).
 
void SetRestLength (double len)
 Set spring rest (free) length. More...
 
void SetSpringCoefficient (double k)
 Set spring coefficient (default: 0). More...
 
void SetDampingCoefficient (double r)
 Set damping coefficient (default: 0). More...
 
void SetActuatorForce (double f)
 Set constant actuation force (default: 0). More...
 
void IsStiff (bool val)
 Declare the forces generated by this spring as stiff (default: false). More...
 
const ChVectorDynamicGetStates () const
 Get current states.
 
double GetRestLength () const
 Get the spring rest (free) length.
 
double GetLength () const
 Get current length.
 
double GetDeformation () const
 Get current deformation.
 
double GetVelocity () const
 Get current length rate of change.
 
double GetForce () const
 Get current force (in the direction of the force element).
 
const ChVectorGetPoint1Rel () const
 Get the endpoint location on 1st body (expressed in body coordinate system)
 
const ChVectorGetPoint1Abs () const
 Get the endpoint location on 1st body (expressed in absolute coordinate system)
 
const ChVectorGetPoint2Rel () const
 Get the endpoint location on 2nd body (expressed in body coordinate system)
 
const ChVectorGetPoint2Abs () const
 Get the endpoint location on 1st body (expressed in absolute coordinate system)
 
double GetSpringCoefficient () const
 Get the value of the spring coefficient. More...
 
double GetDampingCoefficient () const
 Get the value of the damping coefficient. More...
 
double GetActuatorForce () const
 Get the constant acutation force. More...
 
void RegisterForceFunctor (std::shared_ptr< ForceFunctor > functor)
 Specify the functor object for calculating the force.
 
void RegisterODE (ODE *functor)
 Specify the functor object for calculating the ODE right-hand side.
 
void Initialize (std::shared_ptr< ChBody > body1, std::shared_ptr< ChBody > body2, bool pos_are_relative, ChVector<> loc1, ChVector<> loc2, bool auto_rest_length=true, double rest_length=0)
 Initialize the spring, specifying the two bodies to be connected, the location of the two anchor points of each body (each expressed in body or absolute coordinates), and the imposed rest length of the spring. More...
 
virtual void ArchiveOUT (ChArchiveOut &marchive) override
 Method to allow serialization of transient data to archives.
 
virtual void ArchiveIN (ChArchiveIn &marchive) override
 Method to allow deserialization of transient data from archives.
 
- 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() and also add to new collision system / remove from old coll.system.
 
void AddAsset (std::shared_ptr< ChAsset > masset)
 Add an optional asset (it can be used to define visualization shapes, es ChSphereShape, or textures, or custom attached properties that the user can define by creating his class inherited from ChAsset)
 
std::vector< std::shared_ptr< ChAsset > > & GetAssets ()
 Access to the list of optional assets.
 
std::shared_ptr< ChAssetGetAssetN (unsigned int num)
 Access the Nth asset in the list of optional assets.
 
virtual unsigned int GetAssetsFrameNclones ()
 Optionally, a ChPhysicsItem can return multiple asset coordinate systems; this can be helpful if, for example, when a ChPhysicsItem contains 'clones' with the same assets (ex. More...
 
virtual bool GetCollide () const
 Tell if the object is subject to collision. More...
 
virtual void SyncCollisionModels ()
 If this physical item contains one or more collision models, synchronize their coordinates and bounding boxes to the state of the item.
 
virtual void AddCollisionModelsToSystem ()
 If this physical item contains one or more collision models, add them to the system's collision engine.
 
virtual void RemoveCollisionModelsFromSystem ()
 If this physical item contains one or more collision models, remove them from the system's collision engine.
 
virtual void GetTotalAABB (ChVector<> &bbmin, ChVector<> &bbmax)
 Get the entire AABB axis-aligned bounding box of the object. More...
 
virtual void GetCenter (ChVector<> &mcenter)
 Get a symbolic 'center' of the object. More...
 
virtual void StreamINstate (ChStreamInBinary &mstream)
 Method to deserialize only the state (position, speed) Must be implemented by child classes.
 
virtual void StreamOUTstate (ChStreamOutBinary &mstream)
 Method to serialize only the state (position, speed) Must be implemented by child classes.
 
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 SetNoSpeedNoAcceleration ()
 Set zero speed (and zero accelerations) in state, without changing the position. More...
 
virtual int GetDOF_w ()
 Get the number of scalar coordinates of variables derivatives (usually = DOF, but might be different than DOF, ex. More...
 
virtual int GetDOC ()
 Get the number of scalar constraints, if any, in this item.
 
virtual int GetDOC_c ()
 Get the number of scalar constraints, if any, in this item (only bilateral constr.) Children classes might override this.
 
virtual int GetDOC_d ()
 Get the number of scalar constraints, if any, in this item (only unilateral constr.) Children classes might override this.
 
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 IntStateGatherReactions (const unsigned int off_L, ChVectorDynamic<> &L)
 From item's reaction forces to global reaction vector. More...
 
virtual void IntStateScatterReactions (const unsigned int off_L, const ChVectorDynamic<> &L)
 From global reaction vector to item's reaction forces. 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 IntLoadResidual_CqL (const unsigned int off_L, ChVectorDynamic<> &R, const ChVectorDynamic<> &L, const double c)
 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)
 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)
 Takes the term Ct, scale and adds to Qc at given offset: Qc += c*Ct. More...
 
virtual void InjectConstraints (ChSystemDescriptor &mdescriptor)
 Tell to a system descriptor that there are constraints of type ChConstraint in this object (for further passing it to a solver) Basically does nothing, but maybe that inherited classes may specialize this.
 
virtual void ConstraintsBiReset ()
 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)
 Adds the current C (constraint violation) to the known term (b_i) of encapsulated ChConstraints.
 
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 ConstraintsLoadJacobians ()
 Adds the current jacobians in encapsulated ChConstraints.
 
virtual void ConstraintsFetch_react (double factor=1)
 Fetches the reactions from the lagrangian multiplier (l_i) of encapsulated ChConstraints. More...
 
- Public Member Functions inherited from chrono::ChObj
 ChObj (const ChObj &other)
 
int GetIdentifier () const
 Gets the numerical identifier of the object.
 
void SetIdentifier (int id)
 Sets the numerical identifier of the object.
 
double GetChTime () const
 Gets the simulation time of this object.
 
void SetChTime (double m_time)
 Sets the simulation time of this object.
 
const char * GetName () const
 Gets the name of the object as C Ascii null-terminated string -for reading only!
 
void SetName (const char myname[])
 Sets the name of this object, as ascii string.
 
std::string GetNameString () const
 Gets the name of the object as C Ascii null-terminated string.
 
void SetNameString (const std::string &myname)
 Sets the name of this object, as std::string.
 
void MFlagsSetAllOFF (int &mflag)
 
void MFlagsSetAllON (int &mflag)
 
void MFlagSetON (int &mflag, int mask)
 
void MFlagSetOFF (int &mflag, int mask)
 
int MFlagGet (int &mflag, int mask)
 
virtual std::string & ArchiveContainerName ()
 

Friends

class ChSystemParallel
 

Additional Inherited Members

- Protected Attributes inherited from chrono::ChPhysicsItem
ChSystemsystem
 parent system
 
std::vector< std::shared_ptr< ChAsset > > assets
 set of assets
 
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
 the time of simulation for the object
 

Member Function Documentation

◆ GetActuatorForce()

double chrono::ChLinkTSDA::GetActuatorForce ( ) const
inline

Get the constant acutation force.

Meaningful only if no force functor is provided.

◆ GetDampingCoefficient()

double chrono::ChLinkTSDA::GetDampingCoefficient ( ) const
inline

Get the value of the damping coefficient.

Meaningful only if no force functor is provided.

◆ GetSpringCoefficient()

double chrono::ChLinkTSDA::GetSpringCoefficient ( ) const
inline

Get the value of the spring coefficient.

Meaningful only if no force functor is provided.

◆ Initialize()

void chrono::ChLinkTSDA::Initialize ( std::shared_ptr< ChBody body1,
std::shared_ptr< ChBody body2,
bool  pos_are_relative,
ChVector<>  loc1,
ChVector<>  loc2,
bool  auto_rest_length = true,
double  rest_length = 0 
)

Initialize the spring, specifying the two bodies to be connected, the location of the two anchor points of each body (each expressed in body or absolute coordinates), and the imposed rest length of the spring.

Parameters
body1first body to link
body2second body to link
pos_are_relativeif true, point locations are relative to bodies
loc1point on 1st body (rel. or abs., see flag above)
loc2point on 2nd body (rel. or abs., see flag above)
auto_rest_lengthif true, initializes the rest length as the distance between loc1 and loc2
rest_lengthrest length (no need to define if auto_rest_length=true.)

◆ IsStiff()

void chrono::ChLinkTSDA::IsStiff ( bool  val)
inline

Declare the forces generated by this spring as stiff (default: false).

If stiff, Jacobian information will be generated.

◆ SetActuatorForce()

void chrono::ChLinkTSDA::SetActuatorForce ( double  f)
inline

Set constant actuation force (default: 0).

Used only if no force functor is provided.

◆ SetDampingCoefficient()

void chrono::ChLinkTSDA::SetDampingCoefficient ( double  r)
inline

Set damping coefficient (default: 0).

Used only if no force functor is provided.

◆ SetRestLength()

void chrono::ChLinkTSDA::SetRestLength ( double  len)
inline

Set spring rest (free) length.

Optionally, the free length can be calculated from the initial configuration (see Initialize).

◆ SetSpringCoefficient()

void chrono::ChLinkTSDA::SetSpringCoefficient ( double  k)
inline

Set spring coefficient (default: 0).

Used only if no force functor is provided.


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