Capacitive Sensor for Three-Axis Force Measurements and Its Readout Electronics

Abstract

A capacitive sensor that can detect both vertically and horizontally applied contact forces is proposed. The sensor is built on a flexible material (rubber), in which conductive materials are deposited, forming four separate variable capacitors. The overall result is a thin sensor that consists of four variable capacitors with increased mechanical flexibility and robustness and is characterized by a simple structure and manufacture. The interface electronics, which allows reducing the parasitic capacitance effects of the wires, is also described. The experimental tests performed in the aforementioned setup demonstrate that the three-axis capacitive force sensor and its readout circuit are valid concepts to be applied to several fields, ranging from health to robotics, among others.