Hybrid Force Position Controllers for Kuka LWR

Authors: Nicola Piga and Giulio Romualdi

Overview

This package contains three controllers:

• cartesian_position_controller: an operational space controller required to move the end effector in a desired position using inverse kinematics;
• cartesian_inverse_dynamics_controller: an operational space controller performing dynamics inversion (also wrenches at the end effector are compensated);
• hybrid_impedance_controller: an operational space controller implementing the hybrid impedance controller proposed by Spong (it uses the cartesian_inverse_dynamics_controller to perform dynamics inversion);
• ft_sensor_controller: a JointStateInterface controller performing transformations on the force/torque measurements provided by the sensor.

External packages required

In order to run some external packages are required:

• controller_switcher: GUI required to switch controllers and set commands;
• kdljacdot: Jacobian derivative solver from KDL 1.4 (not available in ros up to now);
• kuka-lwr: description of the Kuka LWR manipulator;
• vito-robot: (vito_description only) required for vito robot's torso description and materials;
• ft-calib: FTCalib class from https://github.com/kth-ros-pkg/force_torque_tools exported as ROS library;
• gravity-compensation: gravity-compensation node;
• qb-interface-node: qb_interface_node with support for IMU and compatible with the gravity-compensation node.

In order to compile the GUI you also need ros-*-qt-build.

How to run a simulation

WARNING: in order to run the simulation you MUST set every <damping> and <friction> tag in kuka_lwr.urdf.xacro to 0.0 and disable the <collision> section of the 7-th link.

1. roslaunch lwr_force_position_controllers single_lwr.launch

How to run using the real robot

1. roslaunch lwr_force_position_controllers single_lwr.launch use_lwr_sim:=false lwr_powered:=true