Approximate feedback linearization control for spatial 6-DOF hydraulic parallel manipulator

Traditional feedback linearization approach (TFL) requires a priori knowledge of plant, which is difficult and the computational efficiency of controller is low due to the complex dynamics of spatial 6-DOF hydraulic parallel manipulator. In order to improve the tracking performance of spatial 6-DOF hydraulic parallel manipulator and to conquer the drawbacks of TFL, a novel approximate feedback linearization approach, non-model based method, is proposed in this paper. The mathematical model of spatial hydraulic parallel manipulator is established. The approximate feedback linearization control is designed for the parallel manipulator in joint space, with position and stored force in the previous time step are employed, as a learning tool to yield improved performance. Under Lyapunov theorems, the stability of the presented algorithm is confirmed in the presence of uncertainties. Simulation results show the proposed control is easy and effective to realize path tracking, and it exhibits excellent performance and high efficiency without a precision dynamics of plant. Furthermore, the presented algorithm is well suitable for most industrial applications.