Self-motion determination based on joint velocity bounds for redundant robots

摘要

The movement of redundant robot joints that does not cause any end-effector motion is referred to as self-motion. Control schemes for redundant robots utilize self-motion to optimize a performance criterion. Thus, commanded joint motion at each sampling step is the sum of the minimum joint motion required for the desired end-effector motion and the self-motion. However, the amount of self-motion is limited by the bounds on joint velocities. A scheme is presented to determine the magnitude of self-motion, the direction of which is determined by a gradient projection scheme. Implementation of this scheme on a Motorola 68020 VME bus-based controller of the seven-degree-of-freedom manipulator at the ORNL Center for Engineering Systems Advanced Research (CESAR) is described. 8 refs., 2 figs.