Adaptive backstepping control of hydraulic manipulators with friction compensation using LuGre model

This paper addresses the backstepping control of hydraulic manipulators with friction compensation. A third-order nonlinear dynamic model is used for the controller design while LuGre dynamic friction model with non-uniform friction force variations characterizes the friction forces. The controller is augmented with adaptation laws to compensate for parametric uncertainties in the system dynamics. Acceleration feedback is avoided by using an adaptive observer. Asymptotic stability of the whole control system is proven via Lyapunov analysis. Simulation and experimental results are presented verifying the effectiveness of the developed controller.