PieperSolver Class Reference

Calculates the closed form inverse kinematics of a device using Piepers method. More...

#include <PieperSolver.hpp>

Inherits ClosedFormIK.

Public Types
typedef rw::core::Ptr< PieperSolver >	Ptr
	smart pointer type to this class
Public Types inherited from ClosedFormIK
typedef rw::core::Ptr< ClosedFormIK >	Ptr
	smart pointer type to this class
Public Types inherited from InvKinSolver
typedef rw::core::Ptr< InvKinSolver >	Ptr
	smart pointer type to this class
typedef rw::core::Ptr< const InvKinSolver >	CPtr
	smart pointer type to this const class

Public Member Functions
	PieperSolver (const std::vector< rw::models::DHParameterSet > &dhparams, const rw::math::Transform3D< double > &joint6Tend, const rw::math::Transform3D< double > &baseTdhRef=rw::math::Transform3D<>::identity())
	Constructor. More...
	PieperSolver (rw::models::SerialDevice &dev, const rw::math::Transform3D< double > &joint6Tend, const rw::kinematics::State &state)
	Constructor - the DH parameters is expected to be on each joint in the serial device. When specifying the DH params in the workcell file this constructor can be used. More...
virtual std::vector< math::Q >	solve (const rw::math::Transform3D< double > &baseTend, const rw::kinematics::State &state) const
	Calculates the inverse kinematics. More...
virtual void	setCheckJointLimits (bool check)
	Specifies whether to check joint limits before returning a solution. More...
virtual rw::core::Ptr< const rw::kinematics::Frame >	getTCP () const
	Returns the Tool Center Point (TCP) used when solving the IK problem. More...
Public Member Functions inherited from ClosedFormIK
virtual	~ClosedFormIK ()
	Destructor.
Public Member Functions inherited from InvKinSolver
virtual	~InvKinSolver ()
	destructor

Additional Inherited Members
Static Public Member Functions inherited from ClosedFormIK
static ClosedFormIK::Ptr	make (const rw::models::Device &device, const rw::kinematics::State &state)
	Closed-form IK solver for a device. More...
Protected Member Functions inherited from ClosedFormIK
	ClosedFormIK ()
	Constructor.

Detailed Description

Calculates the closed form inverse kinematics of a device using Piepers method.

To use Piepers method it is required that the device has 6 DOF revolute joints, and that last three axis intersects. In this implementation it will be assumed that the that rotation of these last three axis are equivalent to an Euler ZYZ or Z(-Y)Z rotation.

See Introduction to Robotics Mechanics and Control, by John J. Craig for further information about the algorithm.

Constructor & Destructor Documentation

PieperSolver() [1/2]

PieperSolver	(	const std::vector< rw::models::DHParameterSet > &	dhparams,
		const rw::math::Transform3D< double > &	joint6Tend,
		const rw::math::Transform3D< double > &	baseTdhRef = rw::math::Transform3D<>::identity()
	)

Constructor.

Parameters

dhparams	[in] DH-parameters corresponding to the device
joint6Tend	[in] transform from the 6th joint to the end of the device
baseTdhRef	[in] Transformation between the robot base and the reference frame for the DH-parameters.

PieperSolver() [2/2]

PieperSolver	(	rw::models::SerialDevice &	dev,
		const rw::math::Transform3D< double > &	joint6Tend,
		const rw::kinematics::State &	state
	)

Constructor - the DH parameters is expected to be on each joint in the serial device. When specifying the DH params in the workcell file this constructor can be used.

Parameters

dev	[in] the device for which to extract the DH parameters.
joint6Tend	[in] transform from the 6th joint to the end of the device
state	[in] State using which the transformation between robot base and the DH-parameters reference frame are calculated.

Note

throws an exception if the device has no DH params

Member Function Documentation

getTCP()

virtual rw::core::Ptr<const rw::kinematics::Frame> getTCP ( ) const

virtual

Returns the Tool Center Point (TCP) used when solving the IK problem.

Returns

The TCP Frame used when solving the IK.

Implements InvKinSolver.

setCheckJointLimits()

virtual void setCheckJointLimits ( bool  check )

virtual

Specifies whether to check joint limits before returning a solution.

Parameters

check

[in] If true the method should perform a check that joints are within bounds.

Implements InvKinSolver.

solve()

virtual std::vector<math::Q> solve ( const rw::math::Transform3D< double > &  baseTend, const rw::kinematics::State &  state  ) const

virtual

Calculates the inverse kinematics.

Given a desired \(\robabx{}{desired}{\mathbf{T}}\) and the current state, the method solves the inverse kinematics problem.

If the algorithm is able to identify multiple solutions (e.g. elbow up and down) it will return all of these. Before returning a solution, they may be checked to be within the bounds of the configuration space. (See setCheckJointLimits(bool) )

Parameters

baseTend	[in] Desired base to end transformation \( \robabx{}{desired}{\mathbf{T}}\)
state	[in] State of the device from which to start the iterations

Returns

List of solutions. Notice that the list may be empty.

Note

The targets baseTend must be defined relative to the base of the robot/device.

Implements InvKinSolver.

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

• PieperSolver.hpp