Robust tracking control of 4-SPS(PS) type parallel manipulator via adaptive fuzzy logic approach

The dynamic behavior of electro-hydraulic driven parallel manipulators is highly nonlinear system, the nonlinear behavior arising from load friction as well as the valve flow-pressure drop relationship. This paper is concerned with the robust tracking control of electro-hydraulic driven parallel manipulators with the model uncertainties. An adaptive fuzzy controller is used to estimate the uncertainties of electro-hydraulic system, including the payload variation and stiffness etc. Adaptive fuzzy logic and adaptive backstepping method are employed to provide the solution to the control problem. Simulation results from a electro-hydraulic driven 4-SPS (PS) type parallel manipulator demonstrate its strong robustness against a large of parameters variations and load disturbance and its capability of the trajectories tracking performance.