EXPONENTIALLY STABLE ROBUST-CONTROL LAW FOR ROBOT MANIPULATORS

Robust control has a chattering problem since the control laws are dis continuous functions. To improve this, a boundary layer can be introdu ced; however the system then loses asymptotical stability and is only globally stable. An exponentially stable robust nonlinear control law for robot manipulators, based on Lyapunov stability theory, is present ed. The robust control law is designed using a special Lyapunov functi on which includes both tracking errors and an exponentially convergent additional term, making the stability proof easy, and guarantees that the tracking errors decrease exponentially to zero. For bounded input disturbances, the control laws, with little modification, maintain sa tisfactory system performance. The results of a computer simulation fo r a 2-link manipulator are presented, demonstrating the benefits and r obustness of the proposed algorithm.