基于应变式传感器的压电陶瓷定位系统设计

The Design of Detection System Applied in Piezoelectric Ceramic Positioning Based on Strain Gauge Sensor

基于压电陶瓷驱动的纳米扫描和定位系统,是原子力显微镜系统的关键部件。设计了基于电阻式应变传感器(SGS)的压电陶瓷微纳米位移定位系统。该系统在硬件上采用仪表放大器对SGS应变信号进行RF滤波、放大、模拟滤波处理得到与压电陶瓷位移变化线性相关的电压信号,该信号由高精度AD采集,并通过控制器输出到上位机软件MATLAB中进行噪声分析、FIR数字滤波去噪、线性度分析。实验结果表明,该位移检测系统输出电压噪声峰峰值小于0.5 m V,输出非线性误差小于0.06%,可实现2 nm的位移分辨率。该定位系统可以应用于原子力显微镜的开发中。

PZT actuator for nano-positioning and scanning is one of key device in atomic force microscopy. A piezoelectric ceramic nano-positioning system based on strain gauge sensor was designed. In the system,the voltage signal that is linearly related to the change of the piezoelectric ceramic displacement is obtained by using the instrument amplifier to filter,amplify and simulate the SGS strain signal by RF filtering. The voltage signal is collected by high precision AD and analyzed by noise and FIR digital filtering and linear fitting in MATLAB. The experiment results show that the output voltage noise peak value of the circuit is less than 0.5 mV,and the output nonlinear error is less than 0.06%,the displacement resolution of 2 nm can be achieved. Therefore,the designed actuator can be used to atomic force microscopy system.