Micro Electro Mechanical Systems (MEMS) have an extensive use in different areas of technology. Inertial sensors (accelerometers and gyroscopes) are one of the most widely used devices fabricated using MEMS technology. MEMS accelerometers play an important role in different application areas such as automotive, inertial navigation, guidance, industry, space applications etc. because of low cost, small size, low power, and high reliability. This book presents a detailed SIMULINK model for a conventional capacitive sigma-delta accelerometer system consisting of a MEMS accelerometer, closed-loop readout electronics, and signal processing units (e.g. decimation filters). By using this model, it is possible to estimate the performance of the full accelerometer system including individual noise components, operation range, open loop sensitivity, scale factor, etc. The developed model has been verified through test results using a capacitive MEMS accelerometer, full-custom designed readout electronics, and signal processing unit implemented on a FPGA.
Sensors and devices, based on micromachining technology, known as micro-electro-mechanicalsystems or MEMS, have been received increasing attention so far in recent years. Micromachined inertial sensors, consisting of accelerometers and gyroscopes, are one of the most important types of silicon-based sensor. MEMS capacitive accelerometers have been extensively used in automobiles, inertial navigation systems, earth quake detection and many other bio-medical applications. This book deals with the design of a monolithic 3DOF MEMS capacitive accelerometer using both analytical and numerical techniques. Monolithic accelerometer is a single structure having three individual single axis Accelerometers on a single substrate and utilizes a surface micromachining technology using standard PolyMUMPs process. The designed accelerometer is 3mm×3.1mm in size, has low mechanical noise floor, high sense capacitance and high sensitivity along in-plane (x and y) and out-of-plane (z) axes. Performing a detailed finite element analysis in ANSYS 11.o, physical level simulation has been done to verify the deflection for x, y and z axes with respect to the applied acceleration (g).
This book exposes readers to the research work carried out in realization of High Accuracy Micro-Opto- Electro-Mechanical-(MOEM) Accelerometers. The book has been written with utmost clarity and explanations supported by large number of figures. It would be very much beneficial for the beginners as it covers overview of different classes of accelerometers. It would be also useful for the practicing engineers, post graduate students of aerospace engineering and researchers as issues related to the investigation, design and analysis of MOEM accelerometers are covered. The work presented here explores the usage of guided wave optical phenomena controlled by micromechanical structures to design accelerometer with sub-micro-g accuracy, high bandwidth and scale factor stability of the order of 1 ppm. It includes design and analysis of sensing element for intensity modulated, interferometric and closed loop MOEM accelerometer. The concluding chapter draws several inferences based on the studies presented in different chapters and possible avenues for the further work in area of MOEM accelerometers.