A Design and Optimization of a New, Three-Axis MEMS Capacitive Accelerometer with High Dynamic Range and Sensitivity

Bahram Azizollah Ganji ,Kamran Delfan Hemmati

doi:10.33180/infmidem2020.106

Abstract

In this paper a three-axis capacitor accelerator has been designed, analyzed and optimized using micro-electromechanical systems technology. The accelerometers are generally divided into three categories of single axis, two axes, and three axes in terms of their ability to measure acceleration. In the suggested structure, acceleration measurements are carried out on all three axes simultaneously using a mass and spring system, which makes it possible to achieve a high sensitivity at a low occupancy level without losing other accelerator factors. By taking difference in this structure, it is shown that each axis acceleration has a very low impact on the measured acceleration of the other two axes. If any external factor changes the value of a single capacitor, the original output of the capacitor does not change for detecting acceleration. In other words, the acceleration of any of these three axes, due to its designing features, does not influence the other two axes and the system performance cannot be disrupted by external factors. The other important characteristics of the accelerometers are dynamic range, operating frequency and sensitivity. This study covers a dynamic range up to 1000g and an operating frequency up to 20 kHz. The accelerometer sensitivity is 4fF/g in the z axis direction while it is 9fF/g in the x and y axes directions. In this paper, the simulation of the structure is performed using Intellisuite software. Moreover, a multi-objective genetic optimization algorithm has been used to determine the dimensions of the constituents of the spring and the weight.

Highlights

An accelerometer is a device that measure proper forces of acceleration and is one of the most important sensors widely used in modern systems
The efficiencies of engine, torque transfer system, and brake system can be evaluated via accelerometer
Accelerometers can be employed to measure the vibrations of automobiles, machines, buildings, control systems process, and device installation safety (Yuan et al 2006; Marek et al 2005)

Summary

Introduction

An accelerometer is a device that measure proper forces of acceleration and is one of the most important sensors widely used in modern systems. Accelerometers can provide a completely independent positioning device which detects position with reference to an original point without any use of a receiver or transmitter from a satellite or other sources. This feature is used in the navigation field. Accelerometers can be employed to measure the vibrations of automobiles, machines, buildings, control systems process, and device installation safety (Yuan et al 2006; Marek et al 2005). These applications have all focused on making accelerometers smaller (i.e., occupying less room) and more sensitive. Compared with other types of accelerometers, the capacitive accelerometers have the several advantages such as high precision to a micro-g range, high sensitivity, proper response to the fix input, proper performance against noise, low temperature sensitivity, applicable in a wide range of temperature, low power consumption, low losses and simplicity of mechanical structure (Ashok Kumar et al 2017; Lammel. 2015)

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