A new and simple control strategy for multiple robots involving redundant motion

The dynamic model of a multirobot system with redundant motions is given by equations involving the generalized inverse of a Jacobian matrix, unmodeled joint frictions and external disturbances, and a grasping matrix which is of full-row rank. In the design of the control torque such that the actual path of the payload's mass-center tracks the desired path without demanding extensive online computations, since redundant motion is involved, a matrix involved is not symmetric and the skew-symmetric property is not easy to verify. The first problem can be easily fixed by pre-multiplying another matrix on both sides, while the validity of the skew-symmetric property still remains unclear due to the existence of a generalized inverse. In this paper a control strategy that does not rely on this property is presented. The novelty of the suggested strategy lies in its simplicity in design and implementation.