Backstepping adaptive control of hydraulic Stewart platform using dynamic surface

Hydraulic Stewart platform is characterized by nonlinearity for driving system in essence, severe load coupling among the legs, which bring a great difficulty for controller design and performance improvement. More controller research is either low in tracking performance and movement smoothness when it ignores the nonlinearity and dynamics coupling, or complex in algorithm and has the need of acceleration feedback or observer when the dynamics coupling and nonlinearity is included. To solve the dilemma, a new controller, backstepping adaptive control of hydraulic Stewart platform using dynamic surface is put forward based on the complete dynamics including the upper platform dynamics and hydraulic nonlinearity in driving system. Asymptotic stability of the whole system is proved by Lyapunov method. The proposed algorithm is simple by avoiding the use of acceleration. The simulation results indicate that the control algorithm performs better than the normal PID controller in control precision, dynamic response and depression of the cross coupling.