Analysis And Test For Retraction-extension Dynamic Performance Of A Civil Aircraft Main Landing Gear

The landing gear retraction system is one of the key components of the aircraft, whose workingperformance directly affects the security and reliability during taking-off and landing. Among all theworking parts of modern aircraft, the landing gear retraction system has the highest probability to causeaircraft accidents. Therefore, research for the landing gear retraction system is of great significance. Acivil aircraft main landing gear was taken as the research object in this paper, the retractableperformance was analyzed in depth, the landing gear retraction test load system design and verificationis completed.Aim at the aircraft main landing gear3D retraction mechanism, the principle analysis and thekinematics analysis was completed. Based on D-H matrix method, equations of motion for the landinggear retraction mechanism were listed. Based on software CATIA, the kinematical model of the landinggear was set up and simulated, the3D retraction mechanism motion interference was checked, so as tolay a foundation for the dynamics performance of the landing gear3D retraction mechanism.Aim at the aircraft main landing gear3D retraction mechanism, the dynamics analysis wascompleted. Based on software ADAMS/Aircraft, the main factors which affect the landing gearretraction performance were analyzed, emphatically studied mass force, aerodynamic drag, actuatingcylinder hydraulic pressure and friction. The results show that mass force, aerodynamic drag, actuatingcylinder hydraulic pressure and friction all have influence on the main landing gear retractionperformance, while mass force and actuating cylinder hydraulic pressure have greater influence.Aim at the aircraft main landing gear retraction test, the all-electric servo control load system wasdesigned and analyzed. The servo motor and FTS multi-channel coordinated load system were used tosimulate aerodynamic load, the application of aerodynamic load during the landing gear retraction andextension was realized, the difficulty of the aerodynamic load inconsistency during the landing gearretraction and extension was solved. Based on software MATLAB/SIMULINK, the all-electric servocontrol system was simulated. The results show that, this all-electric servo control system has a gooddynamic tracking performance and the rationality and effectiveness of the load system were verified,which provides support for the landing gear test study.