Design And Application On Automatic Posture Adjustment For Aero-engine Installtion

The aero-engine is generally considered as the “heart” of the aircraft,since it has a significant impact on the performance,stability and economy of the aircraft.The development level of the aero-engine is also a reflection of the national scientific,industrial and defense strength.In the process of aircraft assembly,the engine installation is an extremely important link.However,the engine is of high weight and occupies a large amount of installation space.Besides,the external layout of the engine is very complex,and the requirements of the installation clearance are rather high.Therefore,the engine installation work can be really time-consuming and laborious.At present,most enterprises in our country employ manually operating hydraulic equipment to install engine.Nevertheless,it is extremely difficult to accurately adjust the installation position of the engine till all requirements are met though the manual operation.In addition,this sort of manual operation would increase the labor costs,accident risks and difficulties in ensuring the installation accuracy.In order to deal with problems of low installation precision and efficiency of engine installation,this paper presents an optimized installation technique of the engine.Moreover,based on this technique,an innovative installation method of automatic attitude adjustment has been developed and afterwards applied for the process design and application of the engine installation.First of all,an automatic attitude adjustment platform has been established of the upper and lower two-layer structure to realize the “3+2” degrees of freedom of the engine for automatic adjustment.On the one hand,the upper layer of the platform has been developed by using a precision translation system composed of two sets of precision servo motor,precision linear motion guide rail and precision ball screw.Through two sets of precision servo motor under high speed PLC program control synthesize multiple motion modes,the longitudinal and horizontal degrees of freedom motion of the platform could be achieved.On the other hand,the lower layer has been established by using a precision lifting system composed of 4 sets of precision electric servo cylinder.Through 4 sets of servo cylinder under high speed PLC program control synthesize various up and-down motion,the pitching,rolling and lifting degrees of freedom motion of the platform could be obtained.Additionally,in the present study,a machine vision measurement system and a double-redundancy design method of phase laser ranging have been proposed to measure the spatial position of the engine relative to the aircraft.The measured data would be input into the attitude control system.After the calculation,the system would send corresponding instructions to the electric push rod drive motor and the walking drive motor.Thus,the engine’s installation attitudes,including propulsion,side shift,side roll,lifting,pitching and so on,could be adjusted automatically.Moreover,in this paper,the HD video camera has been used to monitor the clearance between the engine and surrounding structures and accessories,meanwhile,to judge the distances between them.Simultaneously,the linear displacement sensor and the pin shaft force transducer have been employed to sense the linear motion displacementand the gravity of the engine,respectively.All the components mentioned above constitute a closed loop for real-time monitoring of the attitudeof the engine during the installation.Furthermore,the design of the automatic attitude adjustment system has been summarized,and the system has been validated through the engine installation process.Compared with the traditional manual installation method,both of the number of the installation personnel and the installation time could be significantly reduced.The validation result indicates that the automatic attitude adjustment system can meet the requirements of high adjustment accuracy,high installation efficiency and low operation complexity.In general,the engine installationprocess is dramatically optimized.The study result of this paper can meet the requirements of high efficiency and high quality digital installation of the engine,and also provide valuable reference for the research on digital installation of other large parts,which has guiding and promoting effects on the research on the current aircraft digital installation technology.