On-line robot trajectory planning for catching a moving object

The problem of using a manipulator to catch a moving object without any advanced knowledge of its trajectory is discussed, and a heuristic procedure is proposed. The method is divided into two parts: a coarse tuning algorithm first drives the end effector into the neighborhood of the object in near-minimum time; a finite tuning algorithm then provides precise matching of the object´s trajectory to ensure the relative velocity and acceleration at the time of grasping. The resulting sensor-based system is simulated for a two-degree-of-freedom planar robot with a highly nonlinear object path. The approach can rapidly be extended to six-degree-of-freedom manipulators