An on-line robot planning strategy for target interception

Abstract

On-line planning of gross robot motion for moving-object interception is considered in this article within the context of an active prediction planning, and execution (APPE) strategy. The objective is to find an optimal interception point such that the robot end-effector and the object arrive simultaneously at this target pregrasping point. In this approach, the optimality of the selected rendezvous point on the target trajectory is directly dependent on the robot-trajectory planning technique. Thus, for the solution of the general interception problem, three issues must be addressed: (i) optimal rendezvous-point selection, (ii) optimal robot-trajectory planning, and (iii) replanning in response to gross changes in the predicted target trajectory. The effect of uncertainties in the target-trajectory prediction must be considered at each planning stage. Herein, solutions to the first two problems are briefly reviewed as background to the proposed rendezvous-point replanning strategy. This strategy determines when replanning is necessary, modifies the rendezvous point, and iteratively replans robot “patch trajectories” to new interception points. Simulation results using two different on-line robot-motion-generation strategies are also presented. © 1998 John Wiley & Sons, Inc. 15: 97–114, 1998