XQPController Class Reference

An extended version of the QPController. More...

#include <XQPController.hpp>

Classes
class	Constraint
	Constraint for the XQPController. More...

Public Types
enum	ProjectionFrame { BaseFrame = 0 , ControlFrame }
	Enumeration used to specify frame associated with the projection. More...
typedef rw::core::Ptr< XQPController >	Ptr
	Definition of smart pointer to XQPController.

Public Member Functions
	XQPController (rw::core::Ptr< rw::models::Device > device, rw::core::Ptr< rw::kinematics::Frame > controlFrame, const rw::kinematics::State &state, double dt)
	Constructs XQPController. More...
virtual	~XQPController ()
	Destructor.
rw::math::Q	solve (const rw::math::Q &q, const rw::math::Q &dq, const rw::math::VelocityScrew6D<> &tcpvel, const std::list< Constraint > &constraints)
	Solves the inverse kinematics problem. More...
void	setProjection (const Eigen::MatrixXd &P, ProjectionFrame space)
	Setup the projection. More...
void	setAccScale (double scale)
	Sets a scale for the acceleration limits. More...
void	setVelScale (double scale)
	Sets a scale for the velocity limits. More...
void	calculateVelocityLimits (Eigen::VectorXd &lower, Eigen::VectorXd &upper, const rw::math::Q &q, const rw::math::Q &dq)

Detailed Description

An extended version of the QPController.

Notice: Still under development

The XQPController extends the QPController by providing the user with the possibility of adding constraints on the motion. This method follows the algorithm described in [1].

[1]: Write name of paper when published

Member Enumeration Documentation

ProjectionFrame

enum ProjectionFrame

Enumeration used to specify frame associated with the projection.

Enumerator
ControlFrame	Robot Base Frame The Frame specified as the controlFrame

Constructor & Destructor Documentation

XQPController()

XQPController	(	rw::core::Ptr< rw::models::Device >	device,
		rw::core::Ptr< rw::kinematics::Frame >	controlFrame,
		const rw::kinematics::State &	state,
		double	dt
	)

Constructs XQPController.

Parameters

device	[in] Device to control
controlFrame	[in] Frame to control
state	[in] State specifying how frames are assempled
dt	[in] time step size

Member Function Documentation

calculateVelocityLimits()

void calculateVelocityLimits	(	Eigen::VectorXd &	lower,
		Eigen::VectorXd &	upper,
		const rw::math::Q &	q,
		const rw::math::Q &	dq
	)

Calculates the velocity limits

setAccScale()

void setAccScale

(

double

scale

)

Sets a scale for the acceleration limits.

Use this method to scale the acceleration limit e.g. to reduce the power with which it can accelerate.

setProjection()

void setProjection	(	const Eigen::MatrixXd &	P,
		ProjectionFrame	space
	)

Setup the projection.

The traditional relationship between device Jacobian, joint velocities and tool velocity is given by \(J\dot{q}=\dot{q}\). To ignore certain degrees of freedom or put more emphasis (with respect to the least square solution) on some we can multiply with \(P\) to get \(P J\dot{q}=P \dot{x}\).

\(P\) needs to have exactly 6 columns, however the number of row may be less than 6. Use the space flag to specify in which space the projection should occur.

Usage: Setup to ignore tool roll

XQPController* xqp = new XQPController(device, device->getEnd(), state, dt)
Eigen::MatrixXd P = Eigen::MatrixXd::Zero(5,6);
for (int i = 0; i<5; i++)
    P(i,i) = 1;
xqp->setProjection(P, XQPController::ControlFrame);

Usage: Increase the weight of the z-coordinate relative to the base

XQPController* xqp = new XQPController(device, device->getEnd(), state, dt);
Eigen::MatrixXd P = Eigen::MatrixXd::Identity(6,6);
P(2,2) = 100; //Increase the least square weight with a factor of 100
xqp->setProjection(P, XQPController::BaseFrame);

Parameters

P	[in] The projection matrix
space	[in] The space in which to apply the projection

setVelScale()

void setVelScale

(

double

scale

)

Sets a scale for the velocity limits.

Use this method to scale the velocity limits e.g. to reduce the speed of the robot

solve()

rw::math::Q solve	(	const rw::math::Q &	q,
		const rw::math::Q &	dq,
		const rw::math::VelocityScrew6D<> &	tcpvel,
		const std::list< Constraint > &	constraints
	)

Solves the inverse kinematics problem.

Notice that if the constraints cannot be fullfilled, no quarantees for the return value is given.

Parameters

q	[in] Current configuration of the device
dq	[in] Current joint velocities for the device
tcpvel	[in] Desired tool velocity seen in base frame
constraints	[in] List of constraints

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The documentation for this class was generated from the following file:

• XQPController.hpp