Doc. dr. Mitja Kastrevc, univ. dipl. inž., doc. dr. Edvard Detiček, univ. dipl. inž., oba Univerza v Mariboru, Fakulteta za strojništvo

Abstract:
This paper studies the closed-loop control of an electrohydraulic velocity servo system with the use of the Lyapunov theory of nonlinear systems using integrator backstepping.

Two different nonlinear design procedures are employed feedback linearization and backstepping. It is shown that both these techniques can be successfully used to stabilize any chosen operating point of the system. All derived results are validated by computer simulation of the nonlinear mathematical model of the system. Because of the highly nonlinear nature of the electrohydraulic servo system, the conventional control strategies mostly cannot reach desired control objectives. The nonlinear mathematical model of the system contains many nonlinear terms, which influence also the dynamic errors of the control system. Modern strategies should be able to cope with these nonlinearities.

The research studies represented in the paper show the big potential of Lyapunov-based nonlinear controller design procedures, to obtain desired control objectives.

Keywords:
electrohydraulic servo system, nonlinear control, Lyapunov theory, integrator backstepping, computer simulation