Position control of linear electromechanical actuator for spoiler system base on the inverse system method

Abstract

A kind of robust control of linear electromechanical actuator (LEMA) spoiler system for thrust vector control (TVC) in a spacecraft was investigated. This paper presents an inverse system method (ISM) to achieve precise motion control for the LEMA spoiler system, which is based on a voice coil motor. The dynamic model of the LEMA spoiler system is established, and the inverse system of the LEMA spoiler is obtained. By linearization of the nonlinear LEMA spoiler system, the state feedback control is used to control the spoiler to follow the desired spoiler motion. A state variable observer is designed to estimate the unmeasurable state variables. Simulations and experimental setup are used to demonstrate the effectiveness of the proposed control method. The performance of proportional-integral-differential (PID) control is compared to the ISM control in simulation and ISM control is robust to large parameter variations of 50%. The experimental results show close agreement with the simulation results. The proposed method proved effective by achieving a transient time of 5.5 ms and system bandwidth of 20 Hz, so that ISM control method can more effectively handle the parameters’ perturbation, load disturbance, the variation of work temperature, and the LEMA's nonlinearity.