The problem of redundant manipulator collision avoidance in an unstructured environment is addressed in this paper based on the concept of modified impedance control. Instead of using a limited degree of redundancy (as in conventional methods) to find a collision-free trajectory, in the proposed approach, a robot's commanded joint torques are augmented by an "artificial" joint torque to provide correction for collision avoidance. "Artificial" collision forces are generated online according to the robot's posture and environment information (through knowledge of the robot kinematics and environment or proximity sensors on the robot). The corresponding artificial collision forces are converted to equivalent joint torques that would accomplish the collision avoidance manoeuvre. Then, the commanded joint torques are augmented so that a collision-free joint torque profile is achieved. Robot-to-environment collisions, robot self-collisions and robot constraints such as joint limit and singularity avoidance can be achieved using this method.

This paper presents a new control algorithm for eliminating flexible structure residual oscillations. The pulse active damping (PAD) algorithm is developed and applied on the Space Shuttle Remote Manipulator System (RMS), which is probably the best existing example of a practical flexible manipulator. The proposed control algorithm is activated at the end of an RMS manoeuvre in order to damp out the end-effector oscillation in a fast manner. Basically, this is achieved by injecting torque pulses at the shoulder yaw and shoulder pitch joints so that associated cancelling oscillations at the end-effector are excited to "cancel" out the observed in-plane and out-of-plane end-effector vibrations. Robustness of this algorithm to the estimated natural frequency of the system is addressed and improved by a two-pulse control scheme. It is shown that high oscillations can be eliminated efficiently by PAD.

Some of the progress achieved by Thomson-CSF Systems on the mobile servicing system (MSS) Autonomous Robotics Program Phase II is described. The main objective of this program is to develop a concept and its supporting/enabling technologies required to provide a supervised autonomous operation capability for the special purpose dexterous manipulator (SPDM,) on the MSS. The MSS is Canada's contribution to the Space Station Freedom. The authors summarize and highlight the important issues of the supervised autonomous robotic system concept. The functional division responsibility between the human operator and the system is outlined. This division is based on existing capabilities and skills of robots and the human operator to provide an effective operational solution as well as to address the problems of time delays and bandwidth restriction.>