Abstract
For the speedup of robot's task, authors have already proposed STS (State to State) control, which deals with a state (a pair of position and velocity) as a controlled variable and transfers a robot arm's tip from an initial state to a final state in a specified time. In order to realize STS control, the method based on the combination of the trajectory planning and trajectory update is newly proposed in this paper. Since the initial reference trajectory can be planned mathematically and the influence of the robot dynamics is eliminated by the on-line trajectory update, repeated trials for obtaining the series of command positions prior to the task are not needed. Moreover, this method can cope with the change of the final state during the task. A practical STS control system is constructed by employing an open architecture articulated robot and a pin insertion experiment to a moving hole on a belt conveyer is carried out. The accuracy of the final state in the case of applying the proposed method is fairly good compared with that applying the method without updating the trajectory. A pin insertion task under the clearance of ±0.25[mm] is succeeded with almost 100% probability by applying the proposed method.
