Coordinating two serially connected robots for generating large Cartesian velocities

Two coordination methods are proposed for generating large Cartesian velocities while avoiding degeneracy in two serially connected robots, in which the base of one robot is held by the end effector of the other. The first method decomposes a desired Cartesian velocity into two velocities, one for each robots, based on a least-energy consumption criterion. Robot joint velocities are then adjusted using a null space approach to avoid degeneracy. The second method includes a degeneracy index in the cost function. As a result, joint velocities are obtained without any further adjustment