A discrete algorithm for fixed-path trajectory generation at kinematic singularities

An algorithm is presented for computing the necessary time-scaling to allow a non-redundant manipulator to follow a fixed Cartesian path containing kinematic singularities. The resulting trajectory is close to minimum-time, subject to bounds on joint velocities and accelerations. The algorithm assigns a series of knot points along the path, increasing the knot density in the vicinity of singularities. Appropriate path velocities are then computed for each knot point. Two experiments involving the PUMA manipulator are shown