The first objective was to develop algorithms for the trajectory planning of redundant manipulators in an cluttered environment. A series of algorithms were thus developed, based on the discrete potential field approach applied in the Cartesian space. These algorithms lead to a simple and relatively robust trajectory planning. They were developed as part of a contract with the Hydro-Quebec Research Institute (IREQ). Figure 1 shows a simulator used for the development and verification of the algorithms. The operator can control the movement of the effector by specifying either a final destination only or specifying the local cartersian movement of the effector. In both cases, obstacle aviodance is automatically achieved by the algorithm.

The algorithms mentioned above were developed for applications involving the maintenance of live power lines by telerobotic systems. A complete graphic simulator was also developed for this application, so as to simulate the 23 degree of freedom system developed by IREQ. The IREQ system involves a 4 degree of freedom mast, two 7 degree of freedom SARCOS manipulators each monted on sliders and an auxiliary 3 degree of freedom arm. The complete system and working environment are shown in figure 2.

The final aspect involved the development of approach and grasping algorithms which would allow a manipulator to grasp a moving object. A complete simulation of a system consisting of a manipulator and three cameras was developed, which allows a manipulator to track the trajectory of an object arriving into the workspace and to plan the movement of intercepting and grasping this object. This was achieved using the concept of generalized inverse kinematics.