Research And Design On Control Scheme Of Active Side-stick

After fly-by-wire control system is used on aircraft,the aerodynamic moment on the flight control surface cannot be transmitted to the flight controls,resulting in poor handling quality.The stick force of the active side-stick can be adjusted in real time according to the flight status,thereby enhancing the aircraft's handling quality.This paper presents a deep research of the control scheme of the active side-stick system.Firstly,the operating principle of motor-driven active side-stick is analyzed and its mathematical model is established.Then,a semi-closed-loop control structure is designed.In view of the friction torque existing in the mechanical structure,two friction models are analyzed and established.Secondly,based on the analysis of the static and dynamic stick force characteristics of the active side-stick,the impedance control strategy is established,and the stick force measurement method is put forward.Based on the expert PID with feed-forward compensation,the stick force control method is raised.The algorithm of automatic back to zero position is proposed with the improved variable P control algorithm.Furthermore,Aiming at the problem of high precision position control of the active side-stick,an improved ADRC algorithm is presented.In order to overcome the problems of the overshoot in the transition period and high frequency tremor at steady state,a differential control separation method is proposed.The simulation results show that the improved ADRC algorithm can quickly follow the servo control command signal and can resist a large disturbance torque.Finally,a complete control scheme of the active side-stick is designed basing on the modular design idea.The host computer monitoring software is developed,the master controller software is realized by applying the uC/OSII embedded real-time system and the control algorithms are realized.The performance test and analysis are carried out through experiments.According to the test of the active side-stick engineering prototype,the effectiveness of the control scheme studied in this paper is verified.The test results show that the control scheme meets the functional requirements and technical requirements of the active side-stick,and possesses good stick force characteristics and position control accuracy.