A capacitive sensor is a key component of high-precision displacement detection in space missions.However,due to the influence of sensitive structural manufacturing errors and electronics device precision,theoretical and actual system circuit gains often differ.Herein,as the core of the capacitive sensing circuit,the theoretical model of the differential amplifier circuit is analyzed.Considerably,a model of gain and zero bias of the circuit is proposed.Meanwhile,a corresponding modulation calibration method is applied using the sensitive structure engineering prototype to calibrate multiple degrees of freedom from displacement to voltage.Moreover,the calibration scheme feasibility and zero-bias model accuracy are experimentally verified.Results show that the RMSPER(Root Mean Square Percentage Error)value of the calibrated gain coefficient of each channel is＜0.2％o under multiple tests without temperature control.
关键词
电容传感/多自由度标定/敏感结构/零偏模型
Key words
capacitive sensing/multiple degrees of freedom calibration/sensitive structure/zero bias model
维普
万方数据