用于微弱信号及扭矩检测的容栅式扭矩传感器

Capacitive Grid Torque Sensor for Weak Signal and Torque Detection

在对扭矩信号的检测中,传统的扭矩检测方法存在抗干扰能力弱、响应速度慢、准确度较低的不足。为了改善该问题,提出一种基于典型电容电桥和负反馈控制环路相结合的容栅式扭矩传感器电路来检测扭矩的变化。其中负反馈控制环路由控制信号和移相器组成,可用于补偿因电路自身结构和外部噪声干扰所导致的相位偏移,进一步提高了检测电路的准确性。该检测电路首先通过桥式电路将电容信号转变为电压信号,然后经过比较器输出传感器通道和参考通道的相位信息,最后根据相位信息生成的控制信号来补偿信号的相位,从而准确计算出扭矩的大小。并对检测系统进行了仿真和测试。测试结果表明:该方法能够将微弱电容信号灵敏度减小到1%以下,扭转角误差减小到0.001 3 rad以下,可以有效减小噪声的干扰,从而准确、快速地测量出动态扭矩信息。

In the detection of torque signal,the traditional torque detection method has the disadvantages of weak anti⁃interference ability,slow response speed and low accuracy.In order to improve this problem,a capacitive grid torque sensor circuit based on typical capacitance bridge and negative feedback control loop was proposed to detect the change of torque.The negative feedback control loop consists of control signal and phase shifter,which can be used to compensate the phase shift caused by the structure of the circuit itself and external noise interference,further improving the accuracy of the detection circuit.The detection circuit first converted the capacitance signal into the voltage signal through the bridge circuit,then output the phase information of the sensor channel and the reference channel through the comparator,and finally compensated the phase of the signal according to the control signal generated by the phase information,so as to accurately calculate the torque.The detection system was simulated and tested.The test results show that this method can reduce the sensitivity of weak capacitance signal to less than 1%and the torsional angle error to less than 0.0013 rad,and can effectively reduce the noise interference,thus measuring the dynamic torque information accurately and quickly.