chrono::ChLinkPulley Class Reference

Description

Class to create pulleys on two rigid bodies, connected by a belt.

The two bodies must be already connected to a truss by other links, for example two revolute joints (ChLinkLockRevolute), because this link constraints only the rotation.

#include <ChLinkPulley.h>

Inheritance diagram for chrono::ChLinkPulley:
Collaboration diagram for chrono::ChLinkPulley:

Public Member Functions

 ChLinkPulley (const ChLinkPulley &other)
 
virtual ChLinkPulleyClone () const override
 "Virtual" copy constructor (covariant return type).
 
virtual void UpdateTime (double mytime) override
 Updates motion laws, marker positions, etc.
 
void Set_r1 (double mr)
 Set radius of 1st pulley.
 
void Set_r2 (double mr)
 Set radius of 2nd pulley.
 
double Get_r1 () const
 Get radius of 1st pulley.
 
double Get_r2 () const
 Get radius of 2nd pulley.
 
double Get_tau () const
 Get the transmission ratio. Its value is assumed always positive.
 
double Get_phase () const
 Get the initial phase of rotation of pulley A.
 
void Set_phase (double mset)
 Set the initial phase of rotation of pulley A.
 
void Set_checkphase (bool mset)
 If true, enforce check on exact phase between pulleys (otherwise after many simulation steps the phasing may be affected by numerical error accumulation). More...
 
bool Get_checkphase () const
 
double Get_a1 () const
 Get total rotation of 1st pulley, respect to interaxis, in radians.
 
double Get_a2 () const
 Get total rotation of 1st pulley, respect to interaxis, in radians.
 
void Reset_a1a2 ()
 Reset the total rotations of a1 and a2.
 
const ChFrame< double > & Get_local_shaft1 () const
 Get shaft position and direction, for 1st pulley, in body1-relative reference. More...
 
void Set_local_shaft1 (ChFrame< double > mf)
 Set shaft position and direction, for 1st pulley, in body1-relative reference. More...
 
const ChFrame< double > & Get_local_shaft2 () const
 Get shaft position and direction, for 2nd pulley, in body2-relative reference. More...
 
void Set_local_shaft2 (ChFrame< double > mf)
 Set shaft position and direction, for 2nd pulley, in body2-relative reference. More...
 
ChVector Get_shaft_dir1 ()
 Get shaft direction, for 1st pulley, in absolute reference.
 
ChVector Get_shaft_dir2 ()
 Get shaft direction, for 2nd pulley, in absolute reference.
 
ChVector Get_shaft_pos1 ()
 Get shaft position, for 1st pulley, in absolute reference.
 
ChVector Get_shaft_pos2 ()
 Get shaft position, for 2nd pulley, in absolute reference.
 
ChVector Get_belt_up1 () const
 Get the endpoint of belt, on pulley of body1, for the 'upper' segment, in absolute coordinates. More...
 
ChVector Get_belt_up2 () const
 Get the endpoint of belt, on pulley of body2, for the 'upper' segment, in absolute coordinates. More...
 
ChVector Get_belt_low1 () const
 Get the endpoint of belt, on pulley of body1, for the 'lower' segment, in absolute coordinates. More...
 
ChVector Get_belt_low2 () const
 Get the endpoint of belt, on pulley of body1, for the 'lower' segment, in absolute coordinates. More...
 
double GetShaftsDistance () const
 Return distance between the two axes.
 
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()
 
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. 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 ()
 Get the number of scalar coordinates (variables), if any, in this item. 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 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)
 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 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 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 InjectVariables (ChSystemDescriptor &mdescriptor)
 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 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)
 

Protected Attributes

double tau
 transmission coeff.
 
double r1
 radius of pulley in body1
 
double r2
 radius of pulley in body2
 
double phase
 mounting phase angle
 
bool checkphase
 keep pulleys always on phase
 
double a1
 auxiliary
 
double a2
 auxiliary
 
double shaft_dist
 distance between shafts
 
ChVector belt_up1
 upper segment of belt - end on body1.
 
ChVector belt_up2
 upper segment of belt - end on body2.
 
ChVector belt_low1
 lower segment of belt - end on body1.
 
ChVector belt_low2
 lower segment of belt - end on body2.
 
ChFrame< double > local_shaft1
 shaft1 pos & dir (as Z axis), relative to body1
 
ChFrame< double > local_shaft2
 shaft2 pos & dir (as Z axis), relative to body2
 
- 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
 

Additional Inherited Members

 Type of link-lock.

Member Function Documentation

void chrono::ChLinkPulley::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::ChLinkLock.

ChVector chrono::ChLinkPulley::Get_belt_low1 ( ) const

Get the endpoint of belt, on pulley of body1, for the 'lower' segment, in absolute coordinates.

ChVector chrono::ChLinkPulley::Get_belt_low2 ( ) const

Get the endpoint of belt, on pulley of body1, for the 'lower' segment, in absolute coordinates.

ChVector chrono::ChLinkPulley::Get_belt_up1 ( ) const

Get the endpoint of belt, on pulley of body1, for the 'upper' segment, in absolute coordinates.

ChVector chrono::ChLinkPulley::Get_belt_up2 ( ) const

Get the endpoint of belt, on pulley of body2, for the 'upper' segment, in absolute coordinates.

const ChFrame<double>& chrono::ChLinkPulley::Get_local_shaft1 ( ) const

Get shaft position and direction, for 1st pulley, in body1-relative reference.

The shaft direction is the Z axis of that frame.

const ChFrame<double>& chrono::ChLinkPulley::Get_local_shaft2 ( ) const

Get shaft position and direction, for 2nd pulley, in body2-relative reference.

The shaft direction is the Z axis of that frame.

void chrono::ChLinkPulley::Set_checkphase ( bool  mset)

If true, enforce check on exact phase between pulleys (otherwise after many simulation steps the phasing may be affected by numerical error accumulation).

By default, it is turned off, but for the simulation of synchro belts, this should be better turned on. Note that, to ensure the correct phasing during the many rotations, an algorithm will use the a1 and a2 total rotation values, which might be affected by loss of numerical precision after few thousands of revolutions, so this is NOT suited to real-time simulators which must run for many hours.

void chrono::ChLinkPulley::Set_local_shaft1 ( ChFrame< double >  mf)

Set shaft position and direction, for 1st pulley, in body1-relative reference.

The shaft direction is the Z axis of that frame. It should be parallel to shaft 2. Note that the origin of shaft position will be automatically shifted along shaft direction in order to have both pulleys on same plane.

void chrono::ChLinkPulley::Set_local_shaft2 ( ChFrame< double >  mf)

Set shaft position and direction, for 2nd pulley, in body2-relative reference.

The shaft direction is the Z axis of that frame. It should be parallel to shaft 1.