| 摘要 |
A high-accuracy, low-cost rotation rate sensor is based on a vibrating mechanical element induced to laterally oscillate. When rotated, the element, preferably a cantilever beam, is subjected to a Coriolis force that is proportional to the rate of rotation. The Coriolis force, if not counteracted, would cause the beam to move vertically. Vertical motion is detected with a highly sensitive tunneling tip sensor positioned below the beam. A wide bandwidth control circuit applies a counteracting force to the beam to keep the gap between tip and beam constant. This counteracting force varies with and provides an indication of the rotation rate. Lateral oscillation is induced by applying an electrostatic force to the beam with narrow, bipolar pulses that improve the sensor's stability and accuracy. A quadrature suppression circuit is employed if needed to prevent an oscillation that is tending to tilt due to imperfections in sensor construction, by activating electrodes positioned on a substrate below the oscillating beam to counteract the tendency. An alternative embodiment of the invention utilizes a tunneling tip to provide both lateral and vertical position sensing of an oscillating beam.
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