Interactive time optimal robot motion planning and work-cell layout design

The author presents an interactive motion planning system designed to obtain near-time-optimal and obstacle-free paths efficiently. A geometric representation of robot dynamics reduces the motion planning problem to a simple geometric task. A graphic display of the acceleration capabilities of the manipulator tip and the forbidden regions around the obstacles guides the user in interactively selecting a near-time-optimal and obstacle-free path. The selected path is evaluated by the time-optimal velocity profile along that path, obtained by online optimization. Using the interactive system, paths to within 3% of the optimal were computed in very short time compared to conventional optimization methods. Examples of planning the motions of a two-link manipulator operating in a cluttered environment are presented. Where the layout of the workcell makes the paths inefficient or prevents a movement altogether, the system can be used to redesign the cell layout