Design of a Sensor Structure for Linear Displacement Measurement Based on a Capacitive Grid Sensor

A displacement measurement technology that integrates a sensor structure with the component being tested is proposed to address the challenges posed by limited sensor installation in small and compact spaces, and complex electromagnetic environments with intelligent equipment. The sensor comprises a moving-grid shaft and two static-grid rings, wherein the capacitance varies with displacement when they undergo relative motion. By gathering data from two capacitors, a mapping relationship between the sets of capacitors and unique displacements is established, enabling displacement calibration. The feasibility of the sensor is demonstrated through the development of a mathematical model, simulation, and experimental validation. The results demonstrate that the measured capacitance aligns with the simulated value, confirming that our dual-channel capacitance test and calibration scheme are feasible at the same time, and the error between the displacement test and the true value is less than 6% in the selected range. This reasonable and feasible displacement testing scheme combines a capacitive grid sensor with the reciprocating linear motion of the shaft components to achieve integration between a sensor structure and the measured component.