chrono::ChLinkMotorLinearDriveline Class Reference

Description

This is an "interface" from 3D to a powertrain/powertrain that is modeled via 1D elements such as ChShaft, ChShaftsMotor, ChShaftsGearbox, ChShaftsClutch, etc.

This is the most avanced type of "linear motor" because using many of those 1D elements one can build very complex drivelines, for example use this ChLinkMotorLinearDriveline to represent a drive+reducer, where usually the drive moves a recirculating screw or a pulley or a rack-pinion. Hence this takes into account of the inertia of the motor shaft (as in many cases of robotic actuators, that has electric drives+reducers.) At the same time, using 1D elements avoids the unnecessary complication of using complete 3D parts to make screws, spindles, 3D rack-pinions, etc.

The 1D driveline is "interfaced" to the two connected threedimensional parts using two "inner" 1D shafts, each connected to 3D part translation; it is up to the user to build the driveline that connects those two shafts.

Most often the driveline is a graph starting at inner shaft 2 (consider it to be the truss for holding the motor drive, also the support for reducers if any) and ending at inner shaft 1 (consider it to be the output, i.e. the slow-moving slider).

#include <ChLinkMotorLinearDriveline.h>

Inheritance diagram for chrono::ChLinkMotorLinearDriveline:
Collaboration diagram for chrono::ChLinkMotorLinearDriveline:

Public Member Functions

 ChLinkMotorLinearDriveline (const ChLinkMotorLinearDriveline &other)
 
virtual ChLinkMotorLinearDrivelineClone () const override
 "Virtual" copy constructor (covariant return type).
 
void SetSystem (ChSystem *m_system) override
 Set the pointer to the parent ChSystem() and also add to new collision system / remove from old coll.system.
 
std::shared_ptr< ChShaftGetInnerShaft1lin () const
 Access the inner 1D shaft connected to the translation of body1 about dir of linear guide. More...
 
std::shared_ptr< ChShaftGetInnerShaft2lin () const
 Access the inner 1D shaft connected to the translation of body2 about dir of linear guide. More...
 
std::shared_ptr< ChShaftGetInnerShaft2rot () const
 Access the inner 1D shaft connected to the rotation of body2 about dir of linear guide. More...
 
void SetInnerShaft2RotDirection (ChVector<> md)
 Set the direction of the inner rotation axis for body2, expressed in link coordinates Default is VECT_X, same dir of guide, i.e. More...
 
ChVector GetInnerShaft2RotDirection () const
 Get the direction of the inner rotation axis for body2, expressed in link coordinates Default is VECT_X, same dir of guide, i.e. More...
 
double GetInnerForce1 () const
 Get the force between body 1 and inner shaft 1 Note: cohincident with GetMotorForce() of this motor. More...
 
double GetInnerForce2 () const
 Get the force between body 2 and inner translational shaft 2.
 
double GetInnerTorque2 () const
 Get the torque between body 2 and inner rotational shaft 2 (ex. More...
 
virtual double GetMotorForce () const override
 Get the current actuator reaction torque [Nm].
 
void Update (double mytime, bool update_assets) override
 Update state of the LinkMotor.
 
virtual int GetDOF () override
 Get the number of scalar coordinates (variables), if any, in this item. More...
 
virtual int GetDOC () override
 Get the number of scalar constraints, if any, in this item.
 
virtual int GetDOC_c () override
 Get the number of scalar constraints, if any, in this item (only bilateral constr.) Children classes might override this. More...
 
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) 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.
 
virtual void IntStateScatterAcceleration (const unsigned int off_a, const ChStateDelta &a) override
 From global acceleration vector to item's state acceleration.
 
virtual void IntStateIncrement (const unsigned int off_x, ChState &x_new, const ChState &x, const unsigned int off_v, const ChStateDelta &Dv) override
 Computes x_new = x + Dt , using vectors at specified offsets. More...
 
virtual void IntStateGatherReactions (const unsigned int off_L, ChVectorDynamic<> &L) override
 From item's reaction forces to global reaction vector.
 
virtual void IntStateScatterReactions (const unsigned int off_L, const ChVectorDynamic<> &L) override
 From global reaction vector to item's reaction forces.
 
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.
 
virtual void IntLoadResidual_Mv (const unsigned int off, ChVectorDynamic<> &R, const ChVectorDynamic<> &w, 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.
 
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.
 
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.
 
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.
 
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:
 
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:
 
virtual void InjectConstraints (ChSystemDescriptor &mdescriptor) override
 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. More...
 
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 ConstraintsLoadJacobians () override
 Adds the current jacobians in encapsulated ChConstraints.
 
virtual void ConstraintsFetch_react (double factor=1) override
 Fetches the reactions from the lagrangian multiplier (l_i) of encapsulated ChConstraints. More...
 
virtual void InjectVariables (ChSystemDescriptor &mdescriptor) override
 Tell to a system descriptor that there are variables of type ChVariables in this object (for further passing it to a solver) Basically does nothing, but maybe that inherited classes may specialize this. 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 VariablesFbIncrementMq () override
 Adds M*q (masses multiplied current 'qb') to Fb, ex. More...
 
virtual void VariablesQbSetSpeed (double step=0) override
 Fetches the item speed (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 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. More...
 
- Public Member Functions inherited from chrono::ChPhysicsItem
 ChPhysicsItem (const ChPhysicsItem &other)
 
ChSystemGetSystem () const
 Get the pointer to the parent ChSystem()
 
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. More...
 
virtual void AddCollisionModelsToSystem ()
 If this physical item contains one or more collision models, add them to the system's collision engine. More...
 
virtual void RemoveCollisionModelsFromSystem ()
 If this physical item contains one or more collision models, remove them from the system's collision engine. More...
 
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. More...
 
virtual void StreamOUTstate (ChStreamOutBinary &mstream)
 Method to serialize only the state (position, speed) Must be implemented by child classes. 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 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...
 
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 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.
 
virtual void InjectKRMmatrices (ChSystemDescriptor &mdescriptor)
 Tell to a system descriptor that there are items of type ChKblock in this object (for further passing it to a solver) Basically does nothing, but maybe that inherited classes may specialize this. More...
 
virtual void KRMmatricesLoad (double Kfactor, double Rfactor, double Mfactor)
 Adds the current stiffness K and damping R and mass M matrices in encapsulated ChKblock item(s), if any. 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 ()
 

Additional Inherited Members

 Type of guide constraint.
- 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

void chrono::ChLinkMotorLinearDriveline::ArchiveIN ( ChArchiveIn marchive)
overridevirtual

Method to allow deserialization of transient data from archives.

Method to allow de serialization of transient data from archives.

Reimplemented from chrono::ChLinkMotorLinear.

void chrono::ChLinkMotorLinearDriveline::ConstraintsFetch_react ( double  factor = 1)
overridevirtual

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::ChLinkMateGeneric.

int chrono::ChLinkMotorLinearDriveline::GetDOC_c ( )
overridevirtual

Get the number of scalar constraints, if any, in this item (only bilateral constr.) Children classes might override this.

Reimplemented from chrono::ChLinkMateGeneric.

int chrono::ChLinkMotorLinearDriveline::GetDOF ( )
overridevirtual

Get the number of scalar coordinates (variables), if any, in this item.

Children classes must override this.

Reimplemented from chrono::ChPhysicsItem.

double chrono::ChLinkMotorLinearDriveline::GetInnerForce1 ( ) const

Get the force between body 1 and inner shaft 1 Note: cohincident with GetMotorForce() of this motor.

std::shared_ptr<ChShaft> chrono::ChLinkMotorLinearDriveline::GetInnerShaft1lin ( ) const

Access the inner 1D shaft connected to the translation of body1 about dir of linear guide.

The shaft can be connected to other shafts with ChShaftsMotor or similar items.

std::shared_ptr<ChShaft> chrono::ChLinkMotorLinearDriveline::GetInnerShaft2lin ( ) const

Access the inner 1D shaft connected to the translation of body2 about dir of linear guide.

The shaft can be connected to other shafts with ChShaftsMotor or similar items.

std::shared_ptr<ChShaft> chrono::ChLinkMotorLinearDriveline::GetInnerShaft2rot ( ) const

Access the inner 1D shaft connected to the rotation of body2 about dir of linear guide.

This is needed because one might need to design a driveline with rotational 1D components such as ChShaftsMotor, that require an anchoring to a rotational shaft. The shaft can be connected to other shafts with ChShaftsMotor or similar items.

ChVector chrono::ChLinkMotorLinearDriveline::GetInnerShaft2RotDirection ( ) const

Get the direction of the inner rotation axis for body2, expressed in link coordinates Default is VECT_X, same dir of guide, i.e.

useful when anchoring drives with screw transmission.

double chrono::ChLinkMotorLinearDriveline::GetInnerTorque2 ( ) const

Get the torque between body 2 and inner rotational shaft 2 (ex.

might be caused by the inertia reaction of an internal rotation motor that is accelerating)

void chrono::ChLinkMotorLinearDriveline::InjectConstraints ( ChSystemDescriptor mdescriptor)
overridevirtual

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.

Reimplemented from chrono::ChLinkMateGeneric.

void chrono::ChLinkMotorLinearDriveline::InjectVariables ( ChSystemDescriptor mdescriptor)
overridevirtual

Tell to a system descriptor that there are variables of type ChVariables in this object (for further passing it to a solver) Basically does nothing, but maybe that inherited classes may specialize this.

Reimplemented from chrono::ChPhysicsItem.

void chrono::ChLinkMotorLinearDriveline::IntStateGather ( const unsigned int  off_x,
ChState x,
const unsigned int  off_v,
ChStateDelta v,
double &  T 
)
overridevirtual

From item's state to global state vectors y={x,v} pasting the states at the specified offsets.

Reimplemented from chrono::ChPhysicsItem.

void chrono::ChLinkMotorLinearDriveline::IntStateIncrement ( const unsigned int  off_x,
ChState x_new,
const ChState x,
const unsigned int  off_v,
const ChStateDelta Dv 
)
overridevirtual

Computes x_new = x + Dt , using vectors at specified offsets.

By default, when DOF = DOF_w, it does just the sum, but in some cases (ex when using quaternions for rotations) it could do more complex stuff, and children classes might overload it.

Reimplemented from chrono::ChPhysicsItem.

void chrono::ChLinkMotorLinearDriveline::IntStateScatter ( const unsigned int  off_x,
const ChState x,
const unsigned int  off_v,
const ChStateDelta v,
const double  T 
)
overridevirtual

From global state vectors y={x,v} to item's state (and update) fetching the states at the specified offsets.

Reimplemented from chrono::ChPhysicsItem.

void chrono::ChLinkMotorLinearDriveline::SetInnerShaft2RotDirection ( ChVector<>  md)

Set the direction of the inner rotation axis for body2, expressed in link coordinates Default is VECT_X, same dir of guide, i.e.

useful when anchoring drives with screw transmission.

void chrono::ChLinkMotorLinearDriveline::VariablesFbIncrementMq ( )
overridevirtual

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.

void chrono::ChLinkMotorLinearDriveline::VariablesQbIncrementPosition ( double  step)
overridevirtual

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 (Eulero integration).

Reimplemented from chrono::ChPhysicsItem.

void chrono::ChLinkMotorLinearDriveline::VariablesQbLoadSpeed ( )
overridevirtual

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.

void chrono::ChLinkMotorLinearDriveline::VariablesQbSetSpeed ( double  step = 0)
overridevirtual

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.