Description
Physics element that carries its own dynamics, described as a system of ODEs.
The internal states are integrated simultaneous with the containing system and they can be accessed and used coupled with other physics elements.
#include <ChExternalDynamics.h>
Public Member Functions | |
virtual ChExternalDynamics * | Clone () const override |
"Virtual" copy constructor (covariant return type). | |
virtual void | Initialize () |
Initialize the physics item. | |
virtual bool | IsStiff () const |
Declare as stiff (default: false). More... | |
virtual unsigned int | GetNumStates () const |
Get number of states (dimension of y). | |
ChVectorDynamic | GetInitialStates () |
Get the initial values (state at initial time). | |
const ChVectorDynamic & | GetStates () const |
Get current states. | |
const ChVectorDynamic & | GetRHS () const |
Get current RHS. | |
Public Member Functions inherited from chrono::ChPhysicsItem | |
ChPhysicsItem (const ChPhysicsItem &other) | |
ChSystem * | GetSystem () 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< ChVisualModel > | GetVisualModel () 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< ChVisualShape > | GetVisualShape (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< ChVisualShapeFEA > | GetVisualShapeFEA (unsigned int i) const |
Access the specified FEA visualization object in the visualization model (if any). More... | |
virtual ChFrame | GetVisualModelFrame (unsigned int nclone=0) const |
Get the reference frame (expressed in and relative to the absolute frame) of the visual model. 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 | IsActive () const |
Return true if the object is active and included in dynamics. | |
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 () const |
Get the axis-aligned bounding box (AABB) of this object. More... | |
virtual ChVector3d | GetCenter () const |
Get a symbolic 'center' of the object. More... | |
virtual void | Setup () |
Perform setup operations. More... | |
virtual void | Update (bool update_assets=true) |
Perform an update using the current time. | |
void | UpdateVisualModel () |
Utility function to update only the associated visual assets (if any). | |
virtual void | ForceToRest () |
Set zero speed (and zero accelerations) in state, without changing the position. 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 | GetNumConstraintsBilateral () |
Get the number of bilateral 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 | 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 | 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_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 &descriptor) |
Register with the given system descriptor any ChConstraint objects associated with this item. | |
virtual void | LoadConstraintJacobians () |
Compute and load current Jacobians in encapsulated ChConstraint objects. | |
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 | ConstraintsFetch_react (double factor=1) |
Fetches the reactions from the lagrangian multiplier (l_i) of encapsulated ChConstraints. More... | |
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::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 | |
virtual void | SetInitialConditions (ChVectorDynamic<> &y0) |
Set initial conditions. More... | |
virtual void | CalculateRHS (double time, const ChVectorDynamic<> &y, ChVectorDynamic<> &rhs) |
Calculate and return the ODE right-hand side at the provided time and states. More... | |
virtual bool | CalculateJac (double time, const ChVectorDynamic<> &y, const ChVectorDynamic<> &rhs, ChMatrixDynamic<> &J) |
Calculate the Jacobian of the ODE right-hand side with respect to the ODE states. More... | |
virtual void | Update (double time, bool update_assets=true) override |
Perform any updates necessary at the current phase during the solution process. More... | |
virtual unsigned int | GetNumCoordsPosLevel () override |
Get the number of coordinates at the position level. More... | |
ChVariables & | Variables () |
virtual void | InjectVariables (ChSystemDescriptor &descriptor) override |
Register with the given system descriptor any ChVariable objects associated with this item. | |
virtual void | InjectKRMMatrices (ChSystemDescriptor &descriptor) override |
Register with the given system descriptor any ChKRMBlock objects associated with this item. | |
virtual void | IntStateGather (const unsigned int off_x, ChState &x, const unsigned int off_v, ChStateDelta &v, double &T) override |
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) override |
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) override |
From item's state acceleration to global acceleration vector. More... | |
virtual void | IntStateScatterAcceleration (const unsigned int off_a, const ChStateDelta &a) override |
From global acceleration vector to item's state acceleration. More... | |
virtual void | IntLoadResidual_F (const unsigned int off, ChVectorDynamic<> &R, const double c) override |
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<> &v, const double c) override |
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) override |
Adds the lumped mass to a Md vector, representing a mass diagonal matrix. 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 | LoadKRMMatrices (double Kfactor, double Rfactor, double Mfactor) override |
Compute and load current stiffnes (K), damping (R), and mass (M) matrices in encapsulated ChKRMBlock objects. More... | |
virtual void | VariablesFbReset () override |
Sets the 'fb' part (the known term) of the encapsulated ChVariables to zero. | |
virtual void | VariablesFbLoadForces (double factor=1) override |
Adds the current forces (applied to item) into the encapsulated ChVariables, in the 'fb' part: qf+=forces*factor. | |
virtual void | VariablesQbLoadSpeed () override |
Initialize the 'qb' part of the ChVariables with the current value of speeds. More... | |
virtual void | VariablesQbSetSpeed (double step=0) override |
Fetches the item speed (ex. More... | |
virtual void | VariablesFbIncrementMq () override |
Adds M*q (masses multiplied current 'qb') to Fb, ex. More... | |
virtual void | VariablesQbIncrementPosition (double step) override |
Increment item positions by the 'qb' part of the ChVariables, multiplied by a 'step' factor. More... | |
virtual void | ConstraintsFbLoadForces (double factor=1) override |
Adds the current link-forces, if any, (caused by springs, etc.) to the 'fb' vectors of the ChVariables referenced by encapsulated ChConstraints. | |
void | ComputeJac (double time) |
Compute the Jacobian at the current time and state. | |
Protected Member Functions inherited from chrono::ChObj | |
int | GenerateUniqueIdentifier () |
Additional Inherited Members | |
Protected Attributes inherited from chrono::ChPhysicsItem | |
ChSystem * | system |
parent system | |
std::shared_ptr< ChVisualModelInstance > | vis_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
◆ CalculateJac()
|
inlineprotectedvirtual |
Calculate the Jacobian of the ODE right-hand side with respect to the ODE states.
Must load J = df/dy. Only used if the physics item is declared as stiff. If provided, load df/dy into the provided matrix 'jac' (already set to zero before the call) and return 'true'. In that case, the user-provided Jacobian will overwrite the default finite-difference approximation.
- Parameters
-
time current time y current ODE states rhs current ODE right-hand side vector J output Jacobian matrix
◆ CalculateRHS()
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inlineprotectedvirtual |
Calculate and return the ODE right-hand side at the provided time and states.
Must load rhs = f(t,y).
- Parameters
-
time current time y current ODE states rhs output ODE right-hand side vector
◆ GetNumCoordsPosLevel()
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inlineoverrideprotectedvirtual |
Get the number of coordinates at the position level.
Might differ from coordinates at velocity level if quaternions are used for rotations.
Reimplemented from chrono::ChPhysicsItem.
◆ IntFromDescriptor()
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overrideprotectedvirtual |
After a solver solution, fetch values from variables and constraints into vectors:
- Parameters
-
off_v offset for v v vector to where the q 'unknowns' term of the variables will be copied off_L offset for L L vector to where L 'lagrangian ' term of the constraints will be copied
Reimplemented from chrono::ChPhysicsItem.
◆ IntLoadLumpedMass_Md()
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overrideprotectedvirtual |
Adds the lumped mass to a Md vector, representing a mass diagonal matrix.
Used by lumped explicit integrators. If mass lumping is impossible or approximate, adds scalar error to "error" parameter. Md += c*diag(M)
- Parameters
-
off offset in Md vector Md result: Md vector, diagonal of the lumped mass matrix err result: not touched if lumping does not introduce errors c a scaling factor
Reimplemented from chrono::ChPhysicsItem.
◆ IntLoadResidual_F()
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overrideprotectedvirtual |
Takes the F force term, scale and adds to R at given offset: R += c*F.
- Parameters
-
off offset in R residual R result: the R residual, R += c*F c a scaling factor
Reimplemented from chrono::ChPhysicsItem.
Reimplemented in chrono::ChHydraulicActuatorBase.
◆ IntLoadResidual_Mv()
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overrideprotectedvirtual |
Takes the M*v term, multiplying mass by a vector, scale and adds to R at given offset: R += c*M*w.
- Parameters
-
off offset in R residual R result: the R residual, R += c*M*v w the w vector c a scaling factor
Reimplemented from chrono::ChPhysicsItem.
◆ IntStateGather()
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overrideprotectedvirtual |
From item's state to global state vectors y={x,v} pasting the states at the specified offsets.
- Parameters
-
off_x offset in x state vector x state vector, position part off_v offset in v state vector v state vector, speed part T time
Reimplemented from chrono::ChPhysicsItem.
◆ IntStateGatherAcceleration()
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overrideprotectedvirtual |
From item's state acceleration to global acceleration vector.
- Parameters
-
off_a offset in a accel. vector a acceleration part of state vector derivative
Reimplemented from chrono::ChPhysicsItem.
◆ IntStateScatter()
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overrideprotectedvirtual |
From global state vectors y={x,v} to item's state (and update) fetching the states at the specified offsets.
- Parameters
-
off_x offset in x state vector x state vector, position part off_v offset in v state vector v state vector, speed part T time full_update perform complete update
Reimplemented from chrono::ChPhysicsItem.
◆ IntStateScatterAcceleration()
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overrideprotectedvirtual |
From global acceleration vector to item's state acceleration.
- Parameters
-
off_a offset in a accel. vector a acceleration part of state vector derivative
Reimplemented from chrono::ChPhysicsItem.
◆ IntToDescriptor()
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overrideprotectedvirtual |
Prepare variables and constraints to accommodate a solution:
- Parameters
-
off_v offset for v and R v vector copied into the q 'unknowns' term of the variables R vector copied into the F 'force' term of the variables off_L offset for L and Qc L vector copied into the L 'lagrangian ' term of the constraints Qc vector copied into the Qb 'constraint' term of the constraints
Reimplemented from chrono::ChPhysicsItem.
◆ IsStiff()
|
inlinevirtual |
Declare as stiff (default: false).
If stiff, Jacobian information will be generated.
Reimplemented in chrono::ChHydraulicActuatorBase.
◆ LoadKRMMatrices()
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overrideprotectedvirtual |
Compute and load current stiffnes (K), damping (R), and mass (M) matrices in encapsulated ChKRMBlock objects.
The resulting KRM blocks represent linear combinations of the K, R, and M matrices, with the specified coefficients Kfactor, Rfactor,and Mfactor, respectively. Note: signs are flipped from the term dF/dx in the integrator: K = -dF/dq and R = -dF/dv.
Reimplemented from chrono::ChPhysicsItem.
◆ SetInitialConditions()
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inlineprotectedvirtual |
Set initial conditions.
Must load y0 = y(0).
◆ Update()
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overrideprotectedvirtual |
Perform any updates necessary at the current phase during the solution process.
This function is called at least once per step to update auxiliary data, internal states, etc. The default implementation updates the item's time stamp and its visualization assets (if any are defined anf only if requested).
Reimplemented from chrono::ChPhysicsItem.
Reimplemented in chrono::ChHydraulicActuatorBase.
◆ VariablesFbIncrementMq()
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overrideprotectedvirtual |
Adds M*q (masses multiplied current 'qb') to Fb, ex.
if qb is initialized with v_old using VariablesQbLoadSpeed, this method can be used in timestepping schemes that do: M*v_new = M*v_old + forces*dt
Reimplemented from chrono::ChPhysicsItem.
◆ VariablesQbIncrementPosition()
|
overrideprotectedvirtual |
Increment item positions by the 'qb' part of the ChVariables, multiplied by a 'step' factor.
pos+=qb*step If qb is a speed, this behaves like a single step of 1-st order numerical integration (Euler integration).
Reimplemented from chrono::ChPhysicsItem.
◆ VariablesQbLoadSpeed()
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overrideprotectedvirtual |
Initialize the 'qb' part of the ChVariables with the current value of speeds.
Note: since 'qb' is the unknown, this function seems unnecessary, unless used before VariablesFbIncrementMq()
Reimplemented from chrono::ChPhysicsItem.
◆ VariablesQbSetSpeed()
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overrideprotectedvirtual |
Fetches the item speed (ex.
linear and angular vel.in rigid bodies) from the 'qb' part of the ChVariables and sets it as the current item speed. If 'step' is not 0, also should compute the approximate acceleration of the item using backward differences, that is accel=(new_speed-old_speed)/step. Mostly used after the solver provided the solution in ChVariables.
Reimplemented from chrono::ChPhysicsItem.
The documentation for this class was generated from the following files:
- /builds/uwsbel/chrono/src/chrono/physics/ChExternalDynamics.h
- /builds/uwsbel/chrono/src/chrono/physics/ChExternalDynamics.cpp