Design of capacitive sensor for nano piezoelectric positioning platform
Aiming at the problem that resistance strain gauge type sensor on nano piezoelectric positioning platform,cannot meet the positioning precision,a bipolar plate capacitive displacement sensor for non-contact measurement is designed.Firstly,basic measurement principle and closed-loop control principle of capacitive sensor are analyzed in detail,and the inherent edge effect of capacitive sensor is analyzed theoretically and measures of protection ring are taken to eliminate its effect.On the basis of establishing electromagnetic simulation parameter model,the error between the simulation value of the capacitor with the guard ring structure and the ideal value is less than 1.8％.A high-sensitivity operational amplifier-type capacitance detection circuit based on active bridge is improved,so that the circuit has higher resolution and linearity.The sensor is calibrated,the measurement range is 0～30 μm,the linearity is 0.05％,and the resolution is prior to 0.01 μm.
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维普
