Silicon Accelerometers

P. Greiff, R. Hopkins, R. Lawson

Abstract:	A number of emerging markets have been identified for low-cost, small size, moderate accuracy accelerometers in the fields of tactical weapons systems, stabilization controls, robotics, and commercial applications. Micromechanical technology is well-suited to these needs, and a family of silicon-on-Pyrex accelerometers is being developed at Draper Laboratory to meet them. One application is for a system that will be used to monitor the in-flight motion of artillery shells. It requires a shock-resistant set of accelerometers covering a dynamic range from 1 mg to 100 kg. A second area of interest is in a low-g commercial instrument. The development program has concentrated on a miniature pendulous device using capacitive readout and optionally employing a force rebalance mode. This type of instrument has demonstrated good linearity and wide dynamic range. The size of our accelerometer chips is typically about 0.3 to 1 mm. They are fabricated using a micromechanical technology suitable for high-volume production. Details of the design and process will be described, and test results are presented for several different device geometries. It was found that the munitions application goals could be met using just two devices referred to as a loo-kg and a 100-g device, respectively. The combined pair survived shock pulses up to 125 kg, and acceleration measurements were made covering the range of 1 mg to 60 kg. The commercial device uses a more pendulous configuration, and initial testing indicates that the goals of 1-mg resolution and peak-to-peak bias stability of less than 67 mg over -10°C to +85-C can also be achieved with a l-mm design.
Published in:	Proceedings of the 52nd Annual Meeting of The Institute of Navigation (1996) June 19 - 21, 1996 Royal Sonesta Hotel Cambridge, MA
Pages:	713 - 718
Cite this article:	Greiff, P., Hopkins, R., Lawson, R., "Silicon Accelerometers," Proceedings of the 52nd Annual Meeting of The Institute of Navigation (1996), Cambridge, MA, June 1996, pp. 713-718.
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