The focus of this work is stabilization of hydraulic actuators during the transition from free motion to constraint motion and regulating the intermediate impacts that could drive the system unstable. In our past research, we introduced Lyapunov-based nonlinear control schemes capable of fulfilling the above goal by resting the implement on the surface of the environment before starting the sustained-contact motion. The hydraulic actuator’s stick-slip friction effect was, however, either not included in the analysis or not compensated by the control action. In this paper, the application of our previously introduced friction compensating position control scheme is extended to impact regulation of a hydraulic actuator. Theoretical solution and stability analyses as well as actual experiments prove that such control scheme is also effective for asymptotic impact control (with no position steady-state error) of hydraulic actuators in the presence of actuator’s dry friction.
A NONLINEAR CONTROL SCHEME FOR DISCRETE TIME CHAOTIC SYSTEMS
