Delco Electronics Corporation

David Boyd Rich

Mark Billings Kearney

Dan W Chilcott

Gregory Donald Swanson

William James Cleaver

A motion sensor for sensing motion or acceleration of a body, such as the type used in onboard automotive and aerospace safety control system, navigational system or active suspension control system. The motion sensor includes a support frame, a bridge projecting from the support frame, and a proof mass suspended from the support frame by the bridge so as to enable the proof mass to respond to an input force imposed on the motion sensor. The bridge is provided with a strain sensing element that generates an acceleration signal in response to a deflection of the proof mass. The motion sensor further includes a structural feature capable of compensating for mechanically and thermally induced strains imposed on the motion sensor by generating a compensation signal in response to such strains. Finally, the sensor includes circuitry for detecting the acceleration and compensation signals and canceling the compensation signal from the acceleration signal, so as to produce an output signal that more closely corresponds to the input force on the proof mass than does the acceleration signal.

Self-compensating accelerometer

An impact detector includes a center chip of micromachined silicon, a top cap, and a back plate, with the center chip being sandwiched between the top cap and the back plate. The center chip is micromachined to provide a seismic mass, a perimeter ring, and a plurality of beams interconnecting the perimeter ring and the seismic mass. The center chip and back plate mount aligned switch contacts which close to each other when the seismic mass moves from its static or nondisplaced position to its operative or displaced position. An electrostatic attractive force is generated between the seismic mass and the back plate. This electrostatic attractive force is less than the tensile force applied to the seismic mass by the beams so that the seismic mass remains in its static or nondisplaced position unless the impact detector is subjected to an impulsive force of sufficient magnitude and duration such that the inertial reaction force of the seismic mass when coupled with the electrostatic attractive force is greater than the tensile force so that the seismic mass moves to the operative displaced position. In the operative displaced position, the electrostatic attractive force latches the switch contacts to each other until the electrostatic attractive force is reduced and the tensile force can then return the seismic mass to its static or nondisplaced position.

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Indianapolis, IN, United States of America

David Boyd Rich