Task-space regulation of cooperative manipulators

In this paper a new task-space regulation scheme for a system of two cooperative manipulators tightly grasping a rigid object is proposed. The control architecture is based on individual task-space regulators for the two manipulators. in order to overcome problems arising from representation singularities, the unit quaternion is used to describe the orientation of relevant frames. To avoid steady-state internal stresses at the held object, kinetostatic filtering of the control action is introduced together with internal force feedback. Also, the performance of the control scheme is analyzed in the presence of a class of modeling uncertainties. The equilibria of the closed-loop system are then explicitly computed and asymptotic stability is proven via Lyapunov-like analysis. (C) 2000 Elsevier Science Ltd. All rights reserved.