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An Experimental Study on Outer Frame Position Control of Hydraulic Flight Motion Simulator With Model Compensation

The hydraulic flight motion simulator (HFMS) is the key equipment for the hardware-in-the-loop simulation in the field of aerospace and has been widely used on occasions requiring high maneuverability and large power. However, three mismatched uncertainties, including nonlinear friction torque, unbalanced gravity torque, and unknown inertia, bring some certain difficulties for receiving the high-precision outer frame position control of the HFMS. In this article, first, by means of an ingenious experimental design, the coupled friction torque and gravity torque were identified separately. Subsequently, through combining the established mathematical model and identification results, an adaptive robust controller with model compensation was investigated in which adaptive controller is not only used to estimate unknown system parameters but also able to online correct identified parameters, and the robust controller is able to guarantee the stability of the whole system. Additionally, the zero bias of the servo valve was also introduced to assist controller implementation. Finally, experimental results show that by using the method of torque identification to improve the model accuracy, the burden of parameter adaptation and robust items can be effectively alleviated, and the high-precision outer frame position control of HFMS can be realized.