An Optimum Trajectory Planner for Robot Manipulators in Joint-Space and Under Physical Constraints.

In the following work, a new trajectory planning algorithm has been developed, where the minimum-time history of the movement of the robot end-effector is defined. Planning is made in the joint-mode by combining a new approach to polynomial splines along with an exhaustive search technique to identify the best minimum-time trajectory. The uniqueness of this algorithm emerges from (1) unique combination of cubic and quadratic polynomials and (2) the ability to perform the search on local parts of each joint trajectory. A scaling process is applied to these local segments to ensure maximum performance. The method proposed considers all physical and dynamical limitations inherent in the manipulator design, in addition to any geometric constraints imposed on the path. Thus a significant contribution is made through selecting the most accurate, minimum-time, high performance trajectory for a robot. Simulation programs have been written for a study case and results are reported for a PUMA 600 robot manipulator.