DESIGN AND TUNING OF THE LYAPUNOV BASED NONLINEAR POSITION CONTROL OF ELECTROHYDRAULIC SERVO SYSTEMS

A complete study of the development of a nonlinear backstepping controller for an electrohydraulic servo system is shown in this paper. The authors present an optimized nonlinear mathematical model used as fundamental for computer simulation. A proposed nonlinear controller is suitable for research of behavior of the complete system in control. Special attention is paid to the selection of tuning parameters. Using the experience of earlier studies of the state-space controller where the additional feedback signals such as velocity and acceleration signal increase the frequency and damping factor of the system, the results were proved by computer simulation. The results show that by appropriate selection of tuning parameters the system can achieve the best reference signal tracking performance with a small tracking error. The proposed approach seems to be adequate not only for step reference signals but also for ramp and sinusoidal reference signals. However, the parameters of the backstepping controller can be optimized manually to achieve the best results required