A micromachined pendulous oscillating gyroscopic accelerometer

A silicon Pendulous Oscillating Gyroscopic Accelerometer (POGA) was fabricated using deep reactive ion etching (DRIE) and silicon wafer bonding technologies. The accelerometer is composed of three individual layers that are assembled into the final instrument. The top layer uses wafer bonding of an oxidized wafer to a handling wafer to create a silicon-on-oxide wafer pair, in which the oxide layer provides electrical isolation between the mechanical members and the handling layer. The middle layer is a two-gimbal torsionallysupported silicon structure, and is in turn supported by an underlying drive/sense layer. The instrument proved to have better than milli-g resolution and dynamic ranges in excess of l-g (open loop) and approximately 12 milli-g (closed loop). and hence hold the TSM at null. At this null, the rotation of the SDM can be related to the input acceleration. The equilibrium torque equation is given by: