PVDF谷物传感器减振结构的动力学分析

Dynamic Analysis on Vibration Absorber of PVDF Grain Detecting Sensor

为了实现联合收割机工作过程中谷物损失量的实时测量,研究以聚偏氟乙烯(polyvinylidene fluoride,简称PVDF)压电薄膜作为敏感元件的谷物检测传感器,通过由电荷放大、带通滤波、包络检波和电压比较器等构成的信号调制电路,实现谷物冲击信号的检测。为了减小联合收割机振动的干扰,传感器设计为双层隔振结构,分析了减振系统的动力学特性,数值模拟瞬时冲击作用下的响应。将传感器安装在联合收割机振动筛尾端支架上进行谷物检测实验,结果表明,通过合理选择减振材料和调制电路参数,传感器能够从振动噪声背景中有效提取谷粒冲击信号。

To measure the grain loss of combine harvester in real-time,a grain detecting sensor using piezo-electric polyvinylidene fluoride(PVDF) films as sensitive material is presented.Signal processing circuit which is composed of a charge amplifier,band-pass filter,envelope detector and voltage comparator is designed to detect grain impact signal.Double-layer vibration isolation is incorporated in the sensor to eliminate the influence of combine harvester’s vibration.Based on the dynamic analysis of the absorbing system,the sensor response under instantaneous triangular wave impact is numerical simulated.Then,grain detecting experiments are carried out by assembling the sensor on a support stand which fixed on the vibrating cleaning sieve,the results show that with proper setting the parameters of damping material and processing circuit,the sensor can identify grain impact signal effectively from vibrating noise.