Adaptive backstepping type control for electrohydraulic servos

The work considers the control synthesis in the presence of a parametric uncertainty, with application to electrohydraulic servos actuating primary flight controls. The obtained control law, containing a dynamic updating of uncertain parameter, renders the closed loop system stable and guarantees asymptotic tracking of position references. The uncertain parameter is on line adjusted, using in synthesis the methods of control Lyapunov functions and backstepping. Numerical simulations are reported from viewpoint of the servo time constant performance.