Design And Implementation Of Test System Of Bearing Running In Device For Aerospace

Bearing running-in device test system is a set of special bearing performance test and evaluation system.It is an important part of ground test.In order to ensure the reliability of the equipment,special bearings used for steering need to run together after spraying solid lubricant to ensure the smoothness of contact surface.And the friction force during running together should be monitored as the main feedback index.This paper introduces the design and implementation process of the test system of low-speed bearing running-in device and the research on the control algorithm of the friction feedback involved in running-in.Based on the actual tasks,this paper firstly analyzes the overall requirements of the system in detail and formulates a series of technical indicators.On this basis,the design and implementation process of the system are described from three aspects of system hardware,upper computer software and system control algorithm.Considering the high precision and high efficiency of the system,the traditional PID control method is proposed to control the motor.However,the client has put forward higher requirements on speed control.As the roughness of bearing surface is different and the distribution of friction torque is unknown,the fluctuation of speed control is large and the stability is poor.Therefore,the original PID after-control algorithm was changed into a preprediction method in this project.On the basis of traditional feedback control,a feedforward compensator with neural network was added.Through offline learning,the distribution of friction torque at different positions of the bearing was obtained,and then the corresponding current compensation amount at different positions was obtained.In the running-in process,the control system adjusts the current control signals of the motor at different positions in advance according to the compensation law already obtained,changed from passive regulation to active regulation.The new method can reduce the fluctuation degree of rotation speed and improve the stability of run-in process.The hardware and software design of the low-speed bearing running-in device test system for aerospace adopt the modular idea,which is divided into modules according to function.The hardware device includes vacuum module,force loading module,sensing and measuring module,bearing installation module and other physical structures.As the control center,the software mainly realizes the operation functions such as bearing drive,scheduled run-in and report generation.Moreover,the system uses statistical significance test and analysis method to carry out statistical verification of test data and obtain technical indicators of bearing characteristics,so as to provide reference for the evaluation of technical personnel.