Dual mode gyroscope
First Claim
1. A bulk acoustic wave gyroscope comprising:
- a resonator;
a set of drive electrodes including a pair of opposed drive electrodes;
a set of sense electrodes including a pair of opposed sense electrodes; and
a gyroscope control circuit configured to provide drive signals to the set of drive electrodes to drive the resonator to resonate with two disparate drive modes including a fundamental mode and a compound mode, receive sense signals from the pair of opposed sense electrodes to sense two orthogonal sense modes of the resonator including a sensed fundamental mode and a sensed compound mode, and produce a gyroscope rate output signal based on a weighted sum of the sensed fundamental and compound modes,wherein the gyroscope control circuit is configured to sense a differential sensed signal across the pair of opposed sense electrodes at a fundamental mode frequency, and to sense a same polarity sensed signal at the pair of opposed sense electrodes at a compound mode frequency.
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Accused Products
Abstract
A BAW gyroscope is configured to operate with two pairs of orthogonal modes instead of a single pair in order to mitigate the impact of changes in gaps (e.g., introduced from external stresses such as thermal gradients, external shocks, mechanical stress/torque, etc.). Specifically, the BAW gyroscope resonator is configured to be simultaneously driven to resonate with a two disparate resonant modes (referred to herein as the “fundamental” mode and the “compound” mode), with the same set of drive electrodes used to drive both resonant modes (i.e., all of the drive electrodes are used to drive the two drive modes). When the sensor experiences external rotation, energy couples from the driven modes of vibration to two corresponding orthogonal sense modes via the Coriolis force. The same set of sense electrodes is used to sense both sense modes (i.e., all of the sense electrodes are used to sense the two sense modes). The fundamental mode is differential with respect to the electrodes, while the compound mode is seen as common-mode with respect to the electrodes. Thus, differential gap change will impact offset of rate measured with the fundamental mode only, while common-mode gap change will impact offset of rate measured with the compound mode only.
10 Citations
19 Claims
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1. A bulk acoustic wave gyroscope comprising:
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a resonator; a set of drive electrodes including a pair of opposed drive electrodes; a set of sense electrodes including a pair of opposed sense electrodes; and a gyroscope control circuit configured to provide drive signals to the set of drive electrodes to drive the resonator to resonate with two disparate drive modes including a fundamental mode and a compound mode, receive sense signals from the pair of opposed sense electrodes to sense two orthogonal sense modes of the resonator including a sensed fundamental mode and a sensed compound mode, and produce a gyroscope rate output signal based on a weighted sum of the sensed fundamental and compound modes, wherein the gyroscope control circuit is configured to sense a differential sensed signal across the pair of opposed sense electrodes at a fundamental mode frequency, and to sense a same polarity sensed signal at the pair of opposed sense electrodes at a compound mode frequency. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for operating a bulk acoustic wave gyroscope having a resonator, a set of drive electrodes including a pair of opposed drive electrodes, and a set of sense electrodes including a pair of opposed sense electrodes, the method comprising:
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applying a differential signal across the pair of opposed drive electrodes to drive the resonator to resonate with a fundamental mode; applying a signal with a same polarity to the pair of opposed drive electrodes to drive the resonator to resonate with a compound mode; receiving sense signals from the set of sense electrodes and sensing from the received sense signals two orthogonal sense modes of the resonator including a sensed fundamental mode and a sensed compound mode; and producing a gyroscope rate output signal based on a weighted sum of the sensed fundamental and compound modes. - View Dependent Claims (13, 14, 15)
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16. A gyroscope comprising:
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a resonator; a set of drive electrodes including a pair of opposed drive electrodes; a set of sense electrodes including a pair of opposed sense electrodes; and a gyroscope control circuit configured to provide a differential signal across the pair of opposed drive electrodes to drive the resonator to resonate with a first drive mode at a first frequency, provide a signal with a same polarity to the pair of opposed drive electrodes to drive the resonator to resonate with a second drive mode at a second frequency, receive sense signals from the set of sense electrodes to sense a first sensed mode and a second sensed mode of the resonator, and produce a gyroscope rate output signal based on a weighted sum of received sense signals representing the first sensed mode and received sensed signals representing the second sensed mode. - View Dependent Claims (17, 18, 19)
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Specification