Control of Mechanical Systems with Dry Friction

A technique to design a dynamic continuous controller to regulate a class of full-actuated mechanical systems with dry friction is proposed. It is shown that the control eliminates the steady-state error and is robust with respect to parameter uncertainties. A simple method to find the parameters of the controller is also proposed. Moreover, an application of this result to control a 2-DOF underactuated mechanical system with dry friction in the non-actuated joint is described. Here, the control objective is to regulate the nonactuated variable while the position and speed of the actuated joint remain bounded. Performance issues of the developed synthesis are illustrated with numerical and experimental results.