基于电压积分翻转电容法的微位移测量

Micro Displacement Measurement Based on Voltage Integral Inverting Capacitance Method

微小位移测量在工业控制、机械制造等领域应用广泛。提出了一种基于电压积分翻转电容法的微位移测量方法,该方法利用平行板电容器充放电的特性,使输出电压根据电容值的不同而发生周期性的反转,产生相应频率的输出波形。该系统由位移测量电极板、电压积分翻转电路、低通滤波电路和MCU模块组成。位移测量电极板位移变化时,电容也发生相应改变,电压积分翻转电路将电容变化值转化为输出信号的频率变化值。低通滤波电路将输出信号滤波,降低高频噪声的影响。MCU模块计算出频率变化值对应的微小位移变化值。实验结果表明:由线性回归分析,基于电压积分翻转电容法的微位移测量,其线性度误差为2.16%,相对误差为0.06%,与其他基于电容的位移测量方法相比,线性度误差比基于电容式传感器的微位移测量法小0.09%,比ZNXD型电容式传感器位移测量法小0.64%;相对误差比基于电容式传感器的微位移测量法小0.26%,比ZNXD型电容式传感器位移测量法小0.14%,比平板式电容器位移测量法小0.36%。相比之下,基于电压积分翻转电容法的微位移测量具有较好的线性度误差和相对误差。

Micro-displacement measurement is widely used in industrial control, machinery manufacturing and other fields. A micro-displacement measurement method based on voltage integral inverting capacitance method is proposed. The method makes use of the charge-discharge characteristics of parallel plate capacitors to make the output voltage periodically invert according to the different capacitance values, and generates the corresponding frequency output waveform. The system consists of displacement measuring electrode plate, voltage integral overturning circuit, low-pass filter circuit and MCU module. When the displacement measurement electrode plate displacement changes, its capacitance changes accordingly. The voltage integral flipping circuit converts the capacitance change value to the frequency change value of the output signal. Low pass filter circuit will filter the output signal, reduce the influence of high frequency noise. The MCU module calculates the corresponding small displacement change value of the frequency change value. Linearity error is 0.09% less than the micro displacement measurement method based on capacitive sensor, less than ZNXD type capacitance sensor displacement measurement by 0.64%. The relative error is 0.26% less than the micro-displacement measurement method based on capacitive sensor, 0.14% less than the displacement measurement method of ZNXD capacitive sensor, and 0.36% less than the displacement measurement method of flat capacitor. By comparison, the linear error and relative error of voltage integral inverting capacitance method are better.