Study On The Measurement And Control System Of Plain Bearing Fatigue Tester

Plain bearing is widely used in the engine main bearing, connecting rod big end andthe small end bearing, of which quality directly affects the performance of the engineand is also an important index to evaluate the bearing life. In this paper, according to theshortcomings of traditional industry bearing tester’s control system such as singleacquisition parameters, low measuring precision and intelligent level, a high reliability,stability and friendly man-machine interaction measurement and control system isdeveloped integrating a set of data acquisition, processing, storage and control.Firstly, based on a comprehensive analysis of variable frequency structure, hydraulicloading and multi-parameter measurements of the plain bearing fatigue tester, this paperstudies the related problems of the measurement and control system’s hardwareplatform established, selects the appropriate sensors and secondary instruments,explains the methods for obtaining and processing signals such as load, speed,temperature and current and introduces the components of data acquisition system andfrequency control system and the anti-jamming measures of hardware and software.Secordly, it elaborates the processing of dynamic load signal and dynamic load controlas well as establishing a mathematical model of the core element proportional reliefvalve of loading control system in detail. Through the improvement of the traditionalgenetic algorithm, a self-tuning method of PID parameters is proposed based onadaptive genetic algorithm and in this method a general software is developed for tuningPID parameters by Visual C++. The paper uses this software to set PID parameters ofload control system and simulates the unit step response performance in the MATLAB.The results show that the control performance is better with using adaptive geneticalgorithm to set PID parameters. Then, the setting of PID parameters are applied to thereal control system, simulating the loading waveform of half-wave circulation under theactual condition of internal combustion engine. Finally, this paper also focuses on thedevelopment and the module formation process of software system, functions of eachmodular interface, the key techniques used and the reliability, stability, accuracy andintelligence of the developed control system verified by debugging and testing.The control system of plain bearing fatigue machine developed in this paper, not onlysolves the difficult problems of traditional bearing tester simultaneously measuringmultiple parameters, but also improves the levels of accuracy and intelligentmeasurement, which has the important practical significance because of providing a new platform for the analysis and research of industry on the fatigue life，failuremechanism and structural design of plain bearing materials.