The Technical Research On Electronic Emergency Unlocking System Of The Aircraft Main Landing Gear

Aircraft usually has two sets of hydraulic system to ensure the normal retraction of landing gear,so the landing gear emergency release system is the last fortress to ensure the safe landing of aircraft.With the continuous development of multi-electric technology in aircraft system,landing gear emergency release system technology has been greatly promoted.Compared with traditional mechanical emergency release system,all-electric emergency release system has many advantages,such as high reliability,easy detection and so on.Fly-by-wire control technology overseas is quite mature and has been applied in many aircraft types.However,there is still a big gap between domestic technology and foreign advanced technology.Therefore,this paper studies the all-electric emergency release system.Taking the upper lock mechanism of an aircraft landing gear as an example,an allelectric emergency release system is designed and tested,which can provide an important technical storage for all-electric emergency release system of landing gear in China.This paper summarizes the typical landing gear emergency release systems at home and abroad,compares and analyses the advantages and disadvantages of four emergency release systems,and focuses on the key technology of the design of all-electric emergency release system.Taking the upper lock mechanism of the main landing gear of a certain type of aircraft as the research objective,a set of electronic emergency unlocking actuator is designed with full consideration of its space boundary conditions,safety and other factors.A digital prototype is built using CATIA modeling platform,and a redundant electronic control system is designed based on the working mechanism.Based on the simulation and analysis platform of LMS Imagine.Lab AMESim and LMS Virtual.Lab Motion,a joint simulation model of mechanically powered and electrically powered actuation control system for emergency release is established,and the effects of different braking modes of electric actuation on emergency unlocking performance are studied.On the basis of theoretical design and analysis,the prototype and control system platform of allelectric emergency release are built,and the actuating function is verified by experiments.Finally,with regard to landing gear emergency unlocking system,the Failure Mode Effect and Criticality Analysis(FMECA)is carried out.By establishing the Fault Tree Analysis(FTA)of the landing gear emergency unlocking system,the top event failure probability is calculated to verify the conformity to safety requirements.