Novel liquid-based linear capacitive inclination micro-sensor with totally 360° dynamic range

摘要

A capacitive inclination micro-sensor based on the liquid dielectric has been proposed, analysed, and simulated. The sensor structure is cylindrical and is half filled with the Silicone oil. There are three parallel plate capacitors in the structure of the inclinometer, which are formed between two ends of the cylinder. These capacitors have a common plate on one end, while other plates are formed on other end of the cylinder. The authors introduce C_out as a special function of the structural capacitors such that different external weights on three separate capacitors' values helps obtaining linear and continuous relation for C_out versus inclination angle. Tilt application to the sensor tends to the liquid dielectric movement in the cavity and consequently variations of the structural capacitors. The authors plot analytical expressions of the capacitors and C_out versus tilt angle using MATLAB besides simulating inclinometer by COMSOL multiphysics. Extracted results from analysis and simulation are in good agreements. Proposed inclinometer has sensitivity of 8.011 fF/deg in 0-360 degrees range. Cross-axis sensitivity of the sensor is also surveyed. Some specifications of the proposed micro-inclinometer are wide linear measurement range, high sensitivity, simplicity of the structure, and manufacturing process, which could make it attractive for different applications.