改进型共振解调器在轴承故障诊断中的应用

共振解调技术已经在旋转机械故障诊断中得到广泛应用,传统电压型共振解调器模拟电路能够实时、准确地提取低频共振带里的故障特征频率。受电压型运算放大器转换速度较低和二极管的非线性特性这两个方面的制约,通过传统电压型共振解调器的高频信号和微弱信号发生失真现象,从而造成高频噪声背景下的轴承早期故障被误诊或者漏诊。因此,提出了一种改进型共振解调器模拟电路,通过采用第2代电流传输器(CCII+)以及AB类偏置电压补偿,改善了传统电压型共振解调器中包络检波器的性能,使该设计方法在处理高频故障信号和微弱故障信号的精度均有较大提升。随后,将该电路应用于跑合试验台,对滚动轴承典型故障进行了在线诊断。实验结果表明该改进电路不仅拓宽了信号频率适用范围,而且保证了对滚动轴承早期微弱故障的准确提取。

Application of improved resonance demodulator in rolling bearing fault diagnosis

The technology of resonance demodulation is widely used in the fault diagnosis of rotating machinery.The analog circuit of traditional voltage-type resonance demodulator can accurately extract the fault characteristic frequency from the low-frequency resonance band in real time.However, in the envelope detection part of the traditional voltage-type resonance demodulator, the low conversion rate in the voltage-type operational amplifier and the non-linear diode lead to some problems that is after passing the analog circuit of traditional voltage-type resonance demodulator, high frequency signals or weak signals will inevitable be distorted to make the bearing early faults be misdiagnosed or missed diagnosis.Therefore, an improved resonance demodulator, in which a new electronic component of CCII+ is used to replace the original voltage-type operational amplifier and a rectification circuit to counteract threshold voltage of Schottky barrier diode, is proposed in this paper.As a result, the improved resonance demodulator has a larger promotion in handling the accuracy of the fault signal which is high frequency or weak.Subsequently, the improved resonance demodulator is used to detect typical faults of a rolling bearing in real time on the running attrition test bench.The experiment results show that the improved resonance demodulator can not only broaden its applicable frequency range, but also ensure the accurate extraction of rolling bearing early weak faults.