Robust decentralized position/force control of cooperative robots without velocity measurement

A decentralized control scheme for multiple cooperative manipulators system is developed to achieve the desired performance in motion and force tracking in the presence of uncertainties in the dynamic equations of the robots. To reduce the effects of uncertainties in the closed-loop performance, a robust control algorithm using a robustifying term is proposed. Based on the Lyapunov stability method, it is proved that all the signals in the closed-loop, composed of a robot, an observer and a controller are uniformly ultimately bounded. Also to avoid the difficulties of using velocity sensors within the hand architecture an output feedback control scheme with a linear observer is used.