电液伺服疲劳试验机波形幅值的模糊补偿

Fuzzy Compensation for Waveform Amplitude of Electro-Hydraulic Fatigue Testing Machine

在应用电液伺服疲劳试验机对试件进行疲劳性能测试时,随着试验信号频率的增加,试验机所施加到试件上的实际载荷与设定载荷相比会出现幅值衰减的现象,直接影响试验结果的准确性。通过对实际输出波形幅值的检测,将设定幅值与检测幅值的偏差及其偏差变化率作为模糊控制器的输入,经模糊推理得出补偿因子。应用补偿因子对波形的幅值进行实时修正,提高了试验结果的准确性。为充分保证控制过程的实时性,将内环PID(Proportional Integral Derivatie,简称PID)控制算法及外环波形补偿算法分别放在不同的线程中运行。试验结果表明,所提出的波形补偿算法具有精度高、快速性好的特点,能够满足高精度疲劳试验的要求。

When the fatigue behavior of a specimen is tested using an electro-hydraulic fatigue testing machine,the real load amplitude deviates from its set value as the test frequency increases,which influences the accuracy of test results directly.By measuring the real output amplitude,the difference and second difference between set and measured values of waveform were taken as the fuzzy controller's input and the compensation factor was gotten after fuzzy reasoning.After real-time correction for the waveform amplitude from the compensation factor,the accuracy of test results was improved.The inner loop PID control algorithm and the outer one were put into different threads to guarantee the real-time execution.The result shows that the method has the characteristic of high precision and rapid response,and can satisfy the high precision requirement for fatigue tests.