Robust stabilization of nonlinear uncertain plants with backlash or dead zone in the actuator

Actuator nonlinearities are often neglected in control system design, though they can remarkably affect systems performance. This paper presents sliding mode controllers able to robustly stabilize an intrinsically nonlinear uncertain plant, in the presence of dead zone or backlash in the actuator devices. These nonlinearities have been assumed uncertain, too, with known bounds on the parameters. In the case of backlash, two different approaches have been presented, obtained using a "quasistatic" and a "dynamic" description of the nonlinearity. Simulation results for a single input-single output (SISO) plant have been provided, addressing both the stabilization and the servo problem for a mechanical system representing a robot-like system with one link.