Nonlinear control of a hydraulic parallel manipulator

An adaptive nonlinear controller is proposed for position tracking in hydraulic robots by adopting the backstepping methodology. Full system models including rigid body and hydraulic dynamics are incorporated in the design. The tracking errors are shown to be asymptotically stable in the presence of parametric uncertainties using Lyapunov analysis. The controller is applied to a Stewart type hydraulic manipulator. Simulation and experimental results are provided to demonstrate the effectiveness of the approach.