FREQUENCY READOUT GYROSCOPE
First Claim
1. An electromechanical system, comprising:
- a mechanical resonator having a first mode of vibration and an associated first natural frequency, and a second mode of vibration having an associated second natural frequency, wherein angular rate of motion input couples energy between said first mode of vibration and said second mode of vibration;
sensors and actuators for each of the first mode and the second mode for transduction of an electrical signal into a mechanical vibration and transduction of a mechanical vibration into an electrical signal;
sustaining circuitry connected to the sensors and actuators to maintain substantially constant, non-zero velocity amplitude vibrations in the first mode at a first oscillation frequency and the second mode at a second oscillation frequency; and
output circuitry to infer an angular rate of motion from mechanical velocity or displacement of said first mode or said second mode, or both said first mode and said second mode.
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Accused Products
Abstract
A frequency readout gyroscope is provided, having 2 or 3 axes, in which the frequency of the carrier associated with the oscillation of the proof mass changes while the amplitude stays constant. The invention departs from conventional gyroscopes which rely on measuring transducer sense axis displacement (amplitude modulation) to determine angular input rate. The invention utilizes what could be termed a form of frequency modulation, such as evaluating frequency phase difference between the axes of modulation. Examples include gyroscopes having either a quadrature or Lissajous FM mode of operation, in which angle random walk contribution from the electronics is reduced by approximately two orders of magnitude.
37 Citations
46 Claims
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1. An electromechanical system, comprising:
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a mechanical resonator having a first mode of vibration and an associated first natural frequency, and a second mode of vibration having an associated second natural frequency, wherein angular rate of motion input couples energy between said first mode of vibration and said second mode of vibration; sensors and actuators for each of the first mode and the second mode for transduction of an electrical signal into a mechanical vibration and transduction of a mechanical vibration into an electrical signal; sustaining circuitry connected to the sensors and actuators to maintain substantially constant, non-zero velocity amplitude vibrations in the first mode at a first oscillation frequency and the second mode at a second oscillation frequency; and output circuitry to infer an angular rate of motion from mechanical velocity or displacement of said first mode or said second mode, or both said first mode and said second mode. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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24. An electromechanical system, comprising:
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a mechanical resonator having a non-zero average frequency difference between oscillations of said mechanical resonator in a first mode of vibration and a second mode of vibration, wherein angular rate of motion input couples energy between said first mode of vibration and said second mode of vibration; sensors and actuators for each of the first mode and the second mode for transduction of an electrical signal into a mechanical vibration and transduction of a mechanical vibration into an electrical signal; sustaining circuitry connected to the sensors and actuators to maintain substantially constant, non-zero velocity amplitude vibrations in the first mode at a first oscillation frequency and the second mode at a second oscillation frequency; phase and frequency control circuitry coupled with the mechanical resonator and at least one sensor for controlling phase difference, frequency difference, or a combination of phase and frequency difference between said first mode and said second mode; and output circuitry to estimate angular rate of motion from instantaneous frequencies, mechanical velocity, or displacement of said first mode or said second mode, or both said first mode and said second mode. - View Dependent Claims (25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45)
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46. An electromechanical system, comprising:
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a first mechanical resonator having a first mode of vibration and an associated first natural frequency, and a second mode of vibration having an associated second natural frequency, wherein angular rate of motion input couples energy between said first mode of vibration and said second mode of vibration; sensors and actuators for each of the first mode and the second mode for transduction of an electrical signal into a mechanical vibration and transduction of a mechanical vibration into an electrical signal; sustaining circuitry connected to the sensors and actuators to maintain substantially constant, non-zero velocity amplitude vibrations in the first mode at a first oscillation frequency and the second mode at a second oscillation frequency; output circuitry to infer an angular rate of motion from mechanical velocity or displacement of said first mode or said second mode, or both said first mode and said second mode; a second mechanical resonator having a third mode of vibration and an associated third natural frequency, and a fourth mode of vibration having an associated fourth natural frequency, wherein energy from the third mode is coupled to energy from the fourth mode; additional sensors and additional actuators for each of the third mode and the fourth mode for transduction of an electrical signal into a mechanical vibration and transduction of a mechanical vibration into an electrical signal; additional sustaining circuitry for each of the third mode and the fourth mode connected to the additional sensors and additional actuators to maintain substantially continuous, non-zero velocity amplitude vibrations of the third mode at a third oscillation frequency and the fourth mode at a fourth oscillation frequency; and additional output circuitry to determine angular rate of motion from mechanical velocity or displacement of said third mode or said fourth mode, or both said third mode and said fourth mode.
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Specification