Modeling and validation of a 2-DOF parallel manipulator for pose control application

The use of hydraulically actuated parallel manipulator in different industries increasing rapidly due to high rigidity, higher accuracy, less error propagation, fast speed of response, very good controllability, high power to weight ratio, self lubricating property, heat dissimilation characteristic etc. Manipulator with low degree of freedom (DOF) is simple to analysis, synthesis and fabrication compare to the higher DOF manipulator. In the present work hydraulically actuated 2DOF parallel manipulator has been considered for simulation study of the pose (heave and pitch) control application. Low cost hydraulic component (proportional valve with dead band, low speed hydraulic cylinder etc.) configuration has been considered for the system model. In the present study the simplified mathematical model of the manipulator has been developed. The model of the parallel manipulator has been verified with the experimental result. The verified model has been used to study the control performance by a model free fuzzy tuned feedforward bias PID controller for pose control application. The effectiveness of the proposed controller also has been studied. To study the robustness of the proposed controller central, eccentric and variable position of the external loading has been considered on the manipulator with sinusoidal and chirp heave and pitch demand.