Almost disturbance decoupling force control for the electro-hydraulic load simulator with mechanical backlash

Abstract

Abstract This paper proposes an almost disturbance decoupling (ADD) control strategy for solving the force control problem of an electro-hydraulic load simulator containing mechanical backlash. This method can enhance the force tracking performance of the load simulator by decoupling position disturbance and mitigating the backlash effect. Based on a proposed disturbance coupled model of the load simulator, the necessity of adopting the ADD control is explained by the mechanical oscillation analysis with a simple controller under different disturbance situations. Then, the design method and tuning parameters of the ADD controller are discussed. With the ADD controller, the system’s input-to-state stability with respect to disturbance signals is guaranteed, and moreover, the boundary and the convergence speed of the force tracking error are adjustable by tuning the controller parameters. Both simulation results and experimental results demonstrate that the proposed ADD control can achieve much higher force tracking performance than a controller commonly used in industry.