Research On The Loading Characteristics Of The Electrohydraulic Servo System Of The Bearing Test Bench

In recent years,China’s high-speed railway industry has achieved rapid development,with a total construction mileage of 42000 kilometers.Currently,China has basically mastered the design and manufacturing technology of high-speed rail trains,and has independently developed a number of high-speed rail core technologies.However,as the core part of high-speed bullet trains,the manufacturing of axle box bearings remains a difficult problem,and has not yet achieved localization.At present,the axle box bearings used in high-speed bullet trains mostly rely on foreign imports,and the domestic manufacturing of axle box bearings has seriously hindered the process of China’s high-speed railway going global.For the research of axle box bearings,structural design optimization,process improvement,and reliability analysis of axle box bearings require the support of a large amount of bearing test data.Looking up domestic axle box bearing related test equipment,it is temporarily unable to meet the upgrading of manufacturing technology for axle box bearings on high-speed railways in China.Therefore,in order to break the technical blockade of axle box bearings abroad,China urgently develops a high-speed railway axle box bearing test rig and carries out axle box bearing tests to meet the needs of domestic axle box bearings in China.This paper takes the high-speed railway axle box bearing reliability test rig as the research object,and conducts the following research around the electro-hydraulic servo loading system of the bearing test rig:Firstly,an overview of the overall framework of the test bed and system modeling.Analyze the mechanical structure,working principle,performance,and characteristics of the bearing test bench,clarify the hardware system composition of the electro-hydraulic servo loading system,establish mathematical models of servo valves,valve control cylinders,force sensors,and other devices in the loading system,and derive the transfer function of the electro-hydraulic servo system.Then,analyze the stability and control difficulties of the axial and radial loading systems of the test bench.Secondly,electro-hydraulic servo loading control strategy and joint model simulation research.Using Matlab/Simulink,the mathematical model of electro-hydraulic servo loading PID control is simulated,and the optimization effect of the PID controller on the controlled system is analyzed.In order to improve the authenticity of the simulation model of the electro-hydraulic servo loading system,a joint simulation model of AMEsim and Simulink was established.In the face of the complex coupling problem in the parameter adjustment process of the PID controller,this paper proposes using the sparrow search algorithm to improve the control strategy of the PID controller to optimize the simulation effect of the loading system,and compared the simulation curves before and after the optimization to verify the effectiveness of the improved strategy.Finally,the development and testing analysis of the control system for the bearing test bed.According to the technical standards for bearing testing,the control program for the lower computer of the bearing testing platform is compiled based on the Twin CAT platform,and the human-computer interaction interface for the upper computer is designed and produced based on the Win CC platform.Taking the bearing test bench control system as the platform,the axle box bearing loading test was conducted to verify the feasibility of the bearing test bench loading system.