Composite adaptive control of constrained robots

Force control is the main challenge in force/motion control of constrained robots. This paper presents a composite adaptive controller to deal with the force error. The proposed controller is designed and analyzed in two steps. In the first step, the force error is shown to be asymptotically proportional to the residual force. A force feedback signal is introduced to reduce the force error. The second step presents an analytical study on a composite adaptive controller with a focus on the convergence of the residual force. It is proven that the proposed adaptive controller is able to achieve zero tracking and force errors without the persistent excitations.