Design Of Electro-hydraulic Servo Loading Control System Of Landing Gear Actuator Based On Improved Nonlinear Active Disturbance Rejection Algorithm

The landing gear actuator controls the opening and retracting process of the landing gear,which is the key component of the aircraft landing gear system.Therefore,it is particularly important to carry out fatigue and life loading tests on the actuator under the actual working load.The electro-hydraulic servo loading system has many advantages such as high accuracy,fast response,and high power density,so it is widely used in the scheme of reliable loading of important components.Using the loading hydraulic cylinder to carry out high-strength and accurate reciprocating simulated loading on the landing gear actuator by building the electrohydraulic servo loading test-bed of the actuator,the loading hydraulic cylinder can simulate the load received by the actuator during the retraction of the landing gear,and the potential failure and service life of the actuator can be tested.The test results are of great significance to the safety of aircraft takeoff and landing,the design,production,manufacture and subsequent use and maintenance of the landing gear actuator maintenance and replacement are of great significance.However,the nonlinearity,disturbance,load change,and time-varying parameters of the system lead to an increase in the control difficulty of the force-loaded system,making it difficult for traditional control strategies such as PID and nonlinear active disturbance rejection control to achieve the expected control effect.It is necessary to focus on the research on the force control strategy of the electro-hydraulic servo loading system.This thesis takes the force control strategy of the electro-hydraulic servo loading system as the research object,aiming at the low dynamic loading accuracy of the valvecontrolled cylinder force loading system of the landing gear electro-hydraulic servo loading test bench,and it is difficult to meet the requirements of the load spectrum accuracy,which affects the safety and performance reliability judgment of the actuator.Based on the nonlinear active disturbance rejection control algorithm,this thesis designs an improved nonlinear active disturbance rejection control(ADRC)algorithm with higher precision and stronger anti-disturbance capability by using a new fal function to improve the nonlinear state observer.The electro-hydraulic servo loading control system of the actuator is adopted,and the problem of many parameters and difficult tuning of the controller is solved through the genetic particle swarm optimization.This thesis designs a complete electro-hydraulic servo loading measurement and control system based on Lab VIEW software.The physical experimental results show that the control performance of the improved nonlinear ADRC algorithm in the electro-hydraulic servo control force loading system is generally better than PID and general nonlinear ADRC algorithm,and can meet the loading accuracy requirements of the load spectrum of the landing gear electro-hydraulic servo loading test-bed.The research work completed in this thesis mainly includes:(1)According to the loading requirements of landing gear actuator,this thesis studies the research status of electro-hydraulic servo loading equipment and force control strategy at home and abroad,analyzes the future development direction of electrohydraulic servo loading technology,and determines the research purpose,content and technical route of this thesis.(2)According to the working characteristics of the actuator and the control requirements of the electro-hydraulic servo loading system,an improved nonlinear ADRC is designed,and a genetic particle swarm optimization algorithm is designed for its parameter tuning.(3)In AMESim and Simulink,the physical simulation model of electro-hydraulic servo loading test-bed and the improved nonlinear auto disturbance rejection algorithm model are designed respectively,and the three control strategies of electro-hydraulic servo loading system are jointly simulated through the interface setting.The simulation results show that compared with the general nonlinear ADRC algorithm and PID algorithm,the electro-hydraulic servo loading system based on the improved nonlinear ADRC algorithm improves the response ability of the system,has strong robustness to interference,and can solve the technical problem of force loading overshoot.(4)The measurement and control program of electro-hydraulic servo loading system is designed on Lab VIEW software,including the front panel design of measurement and control program,the design of data acquisition program and the design of each module of improved nonlinear auto disturbance rejection algorithm,which lays a foundation for the experimental verification of control strategy.(5)The dynamic and static characteristics and accuracy of the three control algorithms are compared and analyzed by Four test signals on the electro-hydraulic servo loading test-bed.The experimental results show that compared with other control algorithms,the electro-hydraulic servo loading system based on the improved nonlinear auto disturbance rejection algorithm has the characteristics of fast response,high precision capability.