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OSCAR::IDNewtonEuler Class Reference
[Dynamics]

Inverse dynamics using Newton-Euler. More...

#include <IDNewtonEuler.h>

Inheritance diagram for OSCAR::IDNewtonEuler:

[legend]List of all members.


Public Methods
	IDNewtonEuler (unsigned int dof, const String &linkCGandMassFile, const String &linkInertiaFile, const Vector3D &gravity=Vector3D(0.0, 0.0,-9.8))
	IDNewtonEuler (unsigned int dof, const MatrixData &linkCGandMass, const TensorData &linkInertia, const Vector3D &gravity=Vector3D(0.0, 0.0,-9.8))
virtual	~IDNewtonEuler ()
bool	SetBaseJointType (char jointType)
bool	SetLocalTransformations (const Xform *transformations)
const Vector &	GetJointTorques (const Vector &velocity, const Vector &acceleration, const HandPose &eefLoad=HandPose(0, 0, 0, 0, 0, 0))
bool	GetGravityTorques (Vector &torques)
bool	GetVelocityTorques (const Vector &velocity, Vector &torques)
bool	GetAccelerationTorques (const Vector &acceleration, Vector &torques)
const Matrix *	GetInertiaMatrix ()
const Matrix &	GetJointLoads () const
void	SetToolPoint (const Vector3D &tpVector)
Protected Methods
void	crossProduct (Vector &x, const Vector &y, const Vector &z)
void	crossProduct (Vector &result, unsigned int row_m1, const Matrix &matrix1, const Vector &vector2)
void	crossProduct (Vector &result, unsigned int row_m1, const Matrix &matrix1, unsigned int row_m2, const Matrix &matrix2)
Protected Attributes
Matrix *	joint_force
Matrix *	joint_torque
Matrix *	rot_joint_vel
Matrix *	rot_joint_acc
Matrix *	trans_joint_acc
Matrix *	inertial_force
Matrix *	inertial_torque
Matrix *	JointLoads
Xform	tool_point
char	baseJointType
const Xform *	transformations
bool	inertiaUpdated
bool	gravityUpdated

Detailed Description

Author:: Chaten Kapoor

Constructor & Destructor Documentation

OSCAR::IDNewtonEuler::IDNewtonEuler ( unsigned int dof,

const String & linkCGandMassFile,

const String & linkInertiaFile,

const Vector3D & gravity = Vector3D(0.0, 0.0,-9.8)

)

Constructor.

Parameters:

dof Degrees of freedom (number of joints) of the robot.

linkCGandMassFile Name of file containing link center of gravity and mass data. The format of the data is as follows. The number of rows is equal to DOF. The number of columns is 4, with the first three indicating the center of gravity of the link in the local frame and the last one being the mass of that link. The following example is for a 2-D planar robot.

# This file contains centers of gravity and masses for a 2-DOF planar robot.

# X Y Z mass

0.2 0.0 0.0 5 # link 1

0.1 0.0 0.0 3 # link 2

Parameters:

linkInertiaFile Name of file containing link inertia data. The inertia of each link is represented as a 3X3 matrix called inertia tensor written in the frame at the center of gravity of the link. This frame is a local frame so it's fixed relative to the link. The elements of this 3X3 matrix are in the following form.

Ixx Ixy Ixz

Ixy Iyy Iyz

Ixz Iyz Izz

where Ixx, Iyy, and Izz are the mass moments of inertia and Ixy, Ixz, and Iyz are the mass products of inertia.
The number of 3X3 matrices equals to DOF. The following example is for a 2-D planar robot.
# This file contains the inertia tensors for a 2-DOF planar robot.

# Link 1
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.001

# Link 2
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.001

Parameters:

gravity Vector3D object of the gravity constant in the DH frame. Default is Vector3D(0,0,-9.8), which is the gravity constant in SI unit in the Z-direction which is usually the case for spatial robots. For planar robots, it is typically Vector3D(0,-9.8,0).

Exceptions:

dofAndMassDataMismatch dofAndMassDataMismatch

dofAndInertiaDataMismatch dofAndInertiaDataMismatch

OSCAR::IDNewtonEuler::IDNewtonEuler ( unsigned int dof,

const MatrixData & linkCGandMass,

const TensorData & linkInertia,

const Vector3D & gravity = Vector3D(0.0, 0.0,-9.8)

)

Constructor. Same as the above contructor except that the center of gravity and mass data and the inertia data are supplied through MatrixData and TensorData objects instead of data files.

Parameters:

dof Degrees of freedom (number of joints) of the robot.

linkCGandMass MatrixData object containing link center of gravity and mass data. The number of rows is equal to DOF, each corresponding to each link. The number of columns is 4, with the first three indicating the center of gravity of the link and the last one being the mass of that link.

linkInertia TensorData object containing the link inertia data. The inertia of each link is represented as a 3X3 matrix. The number of 3X3 matrices equals to DOF.

gravity Vector3D object of the gravity constant in the DH frame. Default is Vector3D(0,0,-9.8), which is the gravity constant in SI unit in the Z-direction which is usually the case for spatial robots. For planar robots, it is typically Vector3D(0,-9.8,0).

Exceptions:

dofAndMassDataMismatch dofAndMassDataMismatch

dofAndInertiaDataMismatch dofAndInertiaDataMismatch

virtual OSCAR::IDNewtonEuler::~IDNewtonEuler ( ) [virtual]

Member Function Documentation

void OSCAR::IDNewtonEuler::crossProduct ( Vector & result,

unsigned int row_m1,

const Matrix & matrix1,

unsigned int row_m2,

const Matrix & matrix2

) [protected]

void OSCAR::IDNewtonEuler::crossProduct ( Vector & result,

unsigned int row_m1,

const Matrix & matrix1,

const Vector & vector2

) [protected]

void OSCAR::IDNewtonEuler::crossProduct ( Vector & x,

const Vector & y,

const Vector & z

) [protected]

bool OSCAR::IDNewtonEuler::GetAccelerationTorques ( const Vector & acceleration,

Vector & torques

) [virtual]

A pure virtual function for calculating the joint torques due to acceleration.

Returns:
false if torques or acceleration is not of size DOF. Call GetError for more detailed error information. Otherwise, return true.

Parameters:

acceleration The vector of current joint accelerations.

torques Vector object of size DOF returning the acceleration torques.

Exceptions:

vectorSizeMismatch vectorSizeMismatch

Implements OSCAR::InverseDynamics.

bool OSCAR::IDNewtonEuler::GetGravityTorques ( Vector & torques ) [virtual]

A pure virtual function for calculating the gravity torques.

Returns:
true if torques is of size DOF. If not, then false. Call GetError for more detailed error information.

Parameters:

torques Vector object of size DOF returning the gravity torques.

Exceptions:

vectorSizeMismatch vectorSizeMismatch

Implements OSCAR::InverseDynamics.

const Matrix* OSCAR::IDNewtonEuler::GetInertiaMatrix ( ) [virtual]

A pure virtual function for calculating the inertia matrix.

Returns:
A pointer to a constant Matrix object containing the inertia matrix.

Implements OSCAR::InverseDynamics.

const Matrix& OSCAR::IDNewtonEuler::GetJointLoads ( ) const

const Vector& OSCAR::IDNewtonEuler::GetJointTorques ( const Vector & velocity,

const Vector & acceleration,

const HandPose & eefLoad = HandPose(0, 0, 0, 0, 0, 0)

) [virtual]

A pure virtual function for calculating the total joint torques.

Returns:
an Vector object containing the joint torques.

Parameters:

velocity The vector of current joint velocities

acceleration The vector of current joint accelerations.

eefLoad The EEF load.

Exceptions:

vectorSizeMismatch vectorSizeMismatch

Implements OSCAR::InverseDynamics.

bool OSCAR::IDNewtonEuler::GetVelocityTorques ( const Vector & velocity,

Vector & torques

) [virtual]

A pure virtual function for calculating the joint torques due to velocity (Coriolis and centripetal effects).

Returns:
false if torques or velocity is not of size DOF. Call GetError for more detailed error information. Otherwise, return true.

Parameters:

velocity The vector of current joint velocities

torques Vector object of size DOF returning the velocity torques.

Exceptions:

vectorSizeMismatch vectorSizeMismatch

Implements OSCAR::InverseDynamics.

bool OSCAR::IDNewtonEuler::SetBaseJointType ( char jointType )

Call this function to set the type of the base joint: Rotary ('R') or Prismatic ('P').
This is critical to the torque computation. The default is set to 'R'.
Returns:
true if jointType is either 'R' or 'P'. If not, return false.

Parameters:

jointType The type of the base joint. 'R' or 'P'.

bool OSCAR::IDNewtonEuler::SetLocalTransformations ( const Xform * transformations )

MUST call this function before calling any GetXXX() method to set the local transformation matrices.
The transformation matrices are used in all calculations.
Returns:
true if transformations is of correct size. If not, return false.

Parameters:

transformations A pointer to a constant Xform object containing the local transformation matrices. These transformation matrices can be obtained from FKPosition::GetAllLocalTransformations().

void OSCAR::IDNewtonEuler::SetToolPoint ( const Vector3D & tpVector )

This sets the tool point to as defined by the user. If this method is not called the tool point remains coincident with the last link.

Parameters:

tpVector Tool point vector. Can be obtained from RRKinematics::GetTool(Vector3D& toolPoint)