振弦式传感器激振策略优化

Optimization of Vibrating Wire Sensor Excitation Strategy

振弦式传感器的激励常用高压拨弦激振和低压扫频激振两种方式。高压拨弦激振对传感器损伤较大,信号衰减快,测量精度差;低压扫频激振扫描时间长,信号不宜拾取。提出一种反馈式低压激振方法,降低拨弦激振电压对传感器进行预激振,将反馈的振动频率信号作为输出,对传感器进行复振,可以在很短时间内使振弦达到共振状态。设计专用检测电路对调优后的激振策略进行验证,证明该方法激振时间短,共振幅度大。振动幅度的提高可增强抗干扰能力、降低信号处理电路成本、增加可用测量时间、提高频率测量精度。

Vibrating wire sensor commonly used high-voltage plucked excitation or low-voltage scanning frequency excitation.High-voltage plucked excitation had large damage to sensor,with rapid decayed signal and low measurement accuracy;Low-voltage scanning excitation needed to sweep a long time and hard to pick up the signal.This paper presents a low-voltage excitation with feedback method.By pre-excitations,the vibration frequency of the sensor can be got to used as the output of the driver.The feedback signal frequency is very close to the real frequency of the sensor,so the wire can reach resonance state quickly.The optimal excitation strategy was verified by the new designed detection circuit.By this way,excitation time is short,resonance amplitude is large,therefore it can enhance anti-interference ability and lower the cost of signal processing circuit,increase the measurement time and improve the accuracy of measured frequency.