Provides wrappers for performing KDL functions on a designated kinematic chain given a URDF representation of a robot. More...

Inheritance diagram for pykdl_utils.kdl_kinematics.KDLKinematics:

[legend]

List of all members.

Public Member Functions
def	__init__
	Constructor.
def	cart_inertia
	Returns the cartesian space mass matrix at the end_link for the given joint angles.
def	clip_joints_safe
	Clips joint angles to the safety limits.
def	difference_joints
	Returns a difference between the two sets of joint angles while insuring that the shortest angle is returned for the continuous joints.
def	FK
def	forward
	Forward kinematics on the given joint angles, returning the location of the end_link in the base_link's frame.
def	get_joint_limits
def	get_joint_names
def	get_link_names
def	inertia
	Returns the joint space mass matrix at the end_link for the given joint angles.
def	inverse
	Inverse kinematics for a given pose, returning the joint angles required to obtain the target pose.
def	inverse_biased
	Performs an IK search while trying to balance the demands of reaching the goal, maintaining a posture, and prioritizing rotation or position.
def	inverse_biased_search
	inverse_biased with random restarts.
def	inverse_search
	Repeats IK for different sets of random initial angles until a solution is found or the call times out.
def	jacobian
	Returns the Jacobian matrix at the end_link for the given joint angles.
def	joints_in_limits
	Tests to see if the given joint angles are in the joint limits.
def	joints_in_safe_limits
	Tests to see if the given joint angles are in the joint safety limits.
def	random_joint_angles
	Returns a set of random joint angles distributed uniformly in the safety limits.
Public Attributes
	base_link
	chain
	end_link
	joint_limits_lower
	joint_limits_upper
	joint_safety_lower
	joint_safety_upper
	joint_types
	num_joints
	tree
	urdf
Private Member Functions
def	_do_kdl_fk
Private Attributes
	_dyn_kdl
	_fk_kdl
	_ik_p_kdl
	_ik_v_kdl
	_jac_kdl

Detailed Description

Provides wrappers for performing KDL functions on a designated kinematic chain given a URDF representation of a robot.

Definition at line 56 of file kdl_kinematics.py.

Constructor & Destructor Documentation

def pykdl_utils.kdl_kinematics.KDLKinematics.__init__	(	self,
		urdf,
		base_link,
		end_link,
		kdl_tree = `None`
	)

Constructor.

Parameters:

urdf	URDF object of robot.
base_link	Name of the root link of the kinematic chain.
end_link	Name of the end link of the kinematic chain.
kdl_tree	Optional KDL.Tree object to use. If None, one will be generated from the URDF.

Definition at line 64 of file kdl_kinematics.py.

Member Function Documentation

def pykdl_utils.kdl_kinematics.KDLKinematics._do_kdl_fk	(	self,
		q,
		link_number
	)	`[private]`

Definition at line 180 of file kdl_kinematics.py.

def pykdl_utils.kdl_kinematics.KDLKinematics.cart_inertia	(	self,
		q
	)

Returns the cartesian space mass matrix at the end_link for the given joint angles.

Parameters:

q	List of joint angles.

Returns:: 6x6 np.mat Cartesian inertia matrix

Reimplemented in pykdl_utils.joint_kinematics.JointKinematics.

Definition at line 280 of file kdl_kinematics.py.

def pykdl_utils.kdl_kinematics.KDLKinematics.clip_joints_safe	(	self,
		q
	)

Clips joint angles to the safety limits.

Parameters:

List	of joint angles.

Returns:: np.array list of clipped joint angles.

Definition at line 307 of file kdl_kinematics.py.

def pykdl_utils.kdl_kinematics.KDLKinematics.difference_joints	(	self,
		q1,
		q2
	)

Returns a difference between the two sets of joint angles while insuring that the shortest angle is returned for the continuous joints.

Parameters:

q1	List of joint angles.
q2	List of joint angles.

Returns:: np.array of wrapped joint angles for retval = q1 - q2

Definition at line 329 of file kdl_kinematics.py.

def pykdl_utils.kdl_kinematics.KDLKinematics.FK	(	self,
		q,
		link_number = `None`
	)

Definition at line 135 of file kdl_kinematics.py.

def pykdl_utils.kdl_kinematics.KDLKinematics.forward	(	self,
		q,
		end_link = `None`,
		base_link = `None`
	)

Forward kinematics on the given joint angles, returning the location of the end_link in the base_link's frame.

Parameters:

q	List of joint angles for the full kinematic chain.
end_link	Name of the link the pose should be obtained for.
base_link	Name of the root link frame the end_link should be found in.

Returns:: 4x4 numpy.mat homogeneous transformation

Reimplemented in pykdl_utils.joint_kinematics.JointKinematics.

Definition at line 152 of file kdl_kinematics.py.

def pykdl_utils.kdl_kinematics.KDLKinematics.get_joint_limits ( self )

Definition at line 132 of file kdl_kinematics.py.

def pykdl_utils.kdl_kinematics.KDLKinematics.get_joint_names	(	self,
		links = `False`,
		fixed = `False`
	)

Returns:: List of joint names in the kinematic chain.

Definition at line 128 of file kdl_kinematics.py.

def pykdl_utils.kdl_kinematics.KDLKinematics.get_link_names	(	self,
		joints = `False`,
		fixed = `True`
	)

Returns:: List of link names in the kinematic chain.

Definition at line 123 of file kdl_kinematics.py.

def pykdl_utils.kdl_kinematics.KDLKinematics.inertia	(	self,
		q
	)

Returns the joint space mass matrix at the end_link for the given joint angles.

Parameters:

q	List of joint angles.

Returns:: NxN np.mat Inertia matrix

Reimplemented in pykdl_utils.joint_kinematics.JointKinematics.

Definition at line 271 of file kdl_kinematics.py.

def pykdl_utils.kdl_kinematics.KDLKinematics.inverse	(	self,
		pose,
		q_guess = `None`,
		min_joints = `None`,
		max_joints = `None`
	)

Inverse kinematics for a given pose, returning the joint angles required to obtain the target pose.

Parameters:

pose	Pose-like object represeting the target pose of the end effector.
q_guess	List of joint angles to seed the IK search.
min_joints	List of joint angles to lower bound the angles on the IK search. If None, the safety limits are used.
max_joints	List of joint angles to upper bound the angles on the IK search. If None, the safety limits are used.

Returns:: np.array of joint angles needed to reach the pose or None if no solution was found.

Definition at line 205 of file kdl_kinematics.py.

def pykdl_utils.kdl_kinematics.KDLKinematics.inverse_biased	(	self,
		pose,
		q_init,
		q_bias,
		q_bias_weights,
		rot_weight = `1.`,
		bias_vel = `0.01`,
		num_iter = `100`
	)

Performs an IK search while trying to balance the demands of reaching the goal, maintaining a posture, and prioritizing rotation or position.

Definition at line 344 of file kdl_kinematics.py.

def pykdl_utils.kdl_kinematics.KDLKinematics.inverse_biased_search	(	self,
		pos,
		rot,
		q_bias,
		q_bias_weights,
		rot_weight = `1.`,
		bias_vel = `0.01`,
		num_iter = `100`,
		num_search = `20`
	)

inverse_biased with random restarts.

Definition at line 370 of file kdl_kinematics.py.

def pykdl_utils.kdl_kinematics.KDLKinematics.inverse_search	(	self,
		pose,
		timeout = `1.`
	)

Repeats IK for different sets of random initial angles until a solution is found or the call times out.

Parameters:

pose	Pose-like object represeting the target pose of the end effector.
timeout	Time in seconds to look for a solution.

Returns:: np.array of joint angles needed to reach the pose or None if no solution was found.

Definition at line 241 of file kdl_kinematics.py.

def pykdl_utils.kdl_kinematics.KDLKinematics.jacobian	(	self,
		q,
		pos = `None`
	)

Returns the Jacobian matrix at the end_link for the given joint angles.

Parameters:

q	List of joint angles.

Returns:: 6xN np.mat Jacobian

Parameters:

pos	Point in base frame where the jacobian is acting on. If None, we assume the end_link

Definition at line 256 of file kdl_kinematics.py.

def pykdl_utils.kdl_kinematics.KDLKinematics.joints_in_limits	(	self,
		q
	)

Tests to see if the given joint angles are in the joint limits.

Parameters:

List	of joint angles.

Returns:: True if joint angles in joint limits.

Definition at line 289 of file kdl_kinematics.py.

def pykdl_utils.kdl_kinematics.KDLKinematics.joints_in_safe_limits	(	self,
		q
	)

Tests to see if the given joint angles are in the joint safety limits.

Parameters:

List	of joint angles.

Returns:: True if joint angles in joint safety limits.

Definition at line 298 of file kdl_kinematics.py.

def pykdl_utils.kdl_kinematics.KDLKinematics.random_joint_angles ( self )

Returns a set of random joint angles distributed uniformly in the safety limits.

Returns:: np.array list of random joint angles.

Definition at line 315 of file kdl_kinematics.py.

Member Data Documentation

pykdl_utils::kdl_kinematics.KDLKinematics::_dyn_kdl [private]

Definition at line 64 of file kdl_kinematics.py.

pykdl_utils::kdl_kinematics.KDLKinematics::_fk_kdl [private]

Definition at line 64 of file kdl_kinematics.py.

pykdl_utils::kdl_kinematics.KDLKinematics::_ik_p_kdl [private]

Definition at line 64 of file kdl_kinematics.py.

pykdl_utils::kdl_kinematics.KDLKinematics::_ik_v_kdl [private]

Definition at line 64 of file kdl_kinematics.py.

pykdl_utils::kdl_kinematics.KDLKinematics::_jac_kdl [private]

Definition at line 64 of file kdl_kinematics.py.

pykdl_utils::kdl_kinematics.KDLKinematics::base_link

Definition at line 64 of file kdl_kinematics.py.

pykdl_utils::kdl_kinematics.KDLKinematics::chain

Definition at line 64 of file kdl_kinematics.py.

pykdl_utils::kdl_kinematics.KDLKinematics::end_link

Definition at line 64 of file kdl_kinematics.py.

pykdl_utils::kdl_kinematics.KDLKinematics::joint_limits_lower

Definition at line 64 of file kdl_kinematics.py.

pykdl_utils::kdl_kinematics.KDLKinematics::joint_limits_upper

Definition at line 64 of file kdl_kinematics.py.

pykdl_utils::kdl_kinematics.KDLKinematics::joint_safety_lower

Definition at line 64 of file kdl_kinematics.py.

pykdl_utils::kdl_kinematics.KDLKinematics::joint_safety_upper

Definition at line 64 of file kdl_kinematics.py.

pykdl_utils::kdl_kinematics.KDLKinematics::joint_types

Reimplemented in pykdl_utils.joint_kinematics.JointKinematics.

Definition at line 64 of file kdl_kinematics.py.

pykdl_utils::kdl_kinematics.KDLKinematics::num_joints

Definition at line 64 of file kdl_kinematics.py.

pykdl_utils::kdl_kinematics.KDLKinematics::tree

Definition at line 64 of file kdl_kinematics.py.

pykdl_utils::kdl_kinematics.KDLKinematics::urdf

Definition at line 64 of file kdl_kinematics.py.

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

kdl_kinematics.py

Public Member Functions

Public Attributes

Private Member Functions

Private Attributes

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation