Bio-inspired Dual-mode Capacitive Displacement Sensor with Large Range, High Linearity, and Low Hysteresis for Wearable and Underwater Applications

Abstract

Displacement sensors with large measurement ranges, high linearity and low hysteresis are crucial for wearable devices, underwater environments and precision numerical control machines. However, due to the limitations of design principles, traditional displacement sensors find it difficult to achieve these characteristics simultaneously. This work presents a capacitive displacement sensor with a variable-angle plate. Moreover, the sensor exploits edge capacitance to extend the linearity interval. The sensor provides a measurement range of 10 mm with a resolution of 30 \({\upmu}\)m in contact sensing, a linearity exceeding 0.9967, and a response time of less than 30 ms. Additionally, the sensor possesses non-contact sensing capabilities, enabling it to detect the approach and departure of objects such as hands. This dual-mode displacement sensing design strategy exhibits significant application potential in wearable devices, underwater activities, and the safe production of mechanical workshops.