ikpy.chain module

class ikpy.chain.Chain(links, active_links=0, profile='', **kwargs)[source]

Bases: object

The base Chain class

Parameters:
  • links (list) – List of the links of the chain
  • active_links (list) – The list of the positions of the active links
forward_kinematics(joints, full_kinematics=False)[source]

Returns the transformation matrix of the forward kinematics

Parameters:
  • joints (list) – The list of the positions of each joint. Note : Inactive joints must be in the list.
  • full_kinematics (bool) – Return the transorfmation matrixes of each joint
Returns:

The transformation matrix
inverse_kinematic(target, initial_position, first_active_joint=0, **kwargs)[source]

Computes the inverse kinematic on the specified target

Parameters:
  • target (numpy.array) – The target of the inverse kinematic, in meters
  • initial_position (numpy.array) – the initial position of each joint of the chain
  • first_active_joint (int) – The first active joint$
Returns:

The list of the positions of each joint according to the target. Note : Inactive joints are in the list.
plot(joints, ax, target=None, show=False)[source]

Plots the Chain using Matplotlib

Parameters:
  • joints (list) – The list of the positions of each joint
  • ax (matplotlib.axes.Axes) – A matplotlib axes
  • target (numpy.array) – An optional target
  • show (bool) – Display the axe. Defaults to False
classmethod from_urdf_file(urdf_file, base_elements=['base_link'], last_link_vector=None, base_elements_type='joint')[source]

Creates a chain from an URDF file

Parameters:
  • urdf_file (string) – The path of the URDF file
  • base_elements (list of strings) – List of the links beginning the chain
  • last_link_vector (numpy.array) – Optional : The translation vector of the tip.
ikpy.chain.pinv()[source]