Output-feedback global stabilization of a nonlinear benchmark system usinga saturated passivity-based controller

We address the problem of regulation of the benchmark rotational/translatio nal proof mass actuator using a passivity-based controller. We show that a (relatively straightforward) modification of the output feedback saturated input controller proposed by the authors in a previous paper provides a sim ple and robust solution to the global asymptotic stabilization problem. The design technique is based on the practically appealing principles of energ y shaping and damping injection. Computer simulations show that the perform ance is comparable, and in some respects better, than the one obtained with a far more complicated full-state unsaturated feedback controller.