Ring laser gyroscope dither drive system and method
First Claim
1. A dither drive system for a ring laser gyroscope that includes a frame mounted to a flexure having a resonant frequency, the flexure being mounted between a base and the frame such that the frame may be dithered relative to the base, comprising:
- means for forming a digital dither signal indicative of the dither frequency;
means for producing a first digital dither drive signal that is in-phase with the digital dither signal;
means for producing a second digital dither drive signal that is in quadrature with the digital dither signal;
means for converting the first and second digital dither drive signals into corresponding analog dither drive signals; and
means for applying the analog dither drive signals to the flexure to drive the flexure at its resonant frequency.
1 Assignment
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Accused Products
Abstract
A dither drive system for a ring laser gyroscope includes a computer, a digital to analog converter, a filter, and a power amplifier. The system senses the dither frequency of the gyro frame and produces a digital signal that corresponds to a specified dither drive signal and toggles the dither drive signal to drive the flexure at its resonant frequency. The dither drive system generates digital waveforms that approximate the sine function and digital waveforms that approximate the cosine function and applies the digital waveforms in quadrature to the flexure.
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Citations
20 Claims
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1. A dither drive system for a ring laser gyroscope that includes a frame mounted to a flexure having a resonant frequency, the flexure being mounted between a base and the frame such that the frame may be dithered relative to the base, comprising:
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means for forming a digital dither signal indicative of the dither frequency; means for producing a first digital dither drive signal that is in-phase with the digital dither signal; means for producing a second digital dither drive signal that is in quadrature with the digital dither signal; means for converting the first and second digital dither drive signals into corresponding analog dither drive signals; and means for applying the analog dither drive signals to the flexure to drive the flexure at its resonant frequency.
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2. A dither drive system for a ring laser gyroscope that includes a frame mounted to a flexure having a resonant frequency, the flexure being mounted between a base and the frame such that the frame may be dithered in an oscillatory motion relative to the base, comprising:
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means for forming a digital signal indicative of the dither oscillations; means for producing a first digital waveform that corresponds to a specified dither drive signal and frequency, the first digital waveform being in-phase with the digital signal indicative of the dither; means for producing a second digital waveform that corresponds to a specified dither drive signal and frequency, the second digital waveform being in quadrature with the digital signal indicative of the dither; means for driving the flexure with analog signals indicative of the first and second digital waveforms; means for demodulating the digital signal indicative of the dither oscillations with the first digital waveform to obtain an in-phase error signal; means for demodulating the digital signal indicative of the dither oscillations with the second digital waveform to obtain a quadrature phase error signal; and means for nulling the quadrature phase error signal and servoing the inphase error signal to a predetermined reference value.
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3. A dither drive system for a ring laser gyroscope that includes a frame mounted to a base by flexure springs for dithering the frame about a defined sensing axis relative to the base, comprising:
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means for producing a dithering signal that is a measure of the dithering motion of the frame relative to the base; means for producing a first sinusoidal signal having a frequency substantially at a predetermined resonant frequency of the flexure and frame; means for producing a second sinusoidal signal in phase quadrature with and at the same frequency as the first sinusoidal signal; means for determining the difference in phase between the dithering signal and the first sinusoidal signal to produce an in phase error signal; means for determining the difference in phase between the dithering signal and the second sinusoidal signal to produce a quadrature phase error signal; and means for nulling the quadrature phase error signal and for servoing the in-phase error signal to a predetermined reference value. - View Dependent Claims (4, 5, 6, 7, 8, 9, 10)
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11. A method for controlling a dither drive system for a ring laser gyroscope that includes a frame mounted to a flexure having a resonant frequency, the flexure being mounted between a base and the frame such that the frame may be dithered relative to the base, comprising the steps of:
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forming a digital dither signal indicative of the dither frequency; producing a first digital dither drive signal that is in-phase with the digital dither signal; producing a first digital dither drive signal that is in-phase with the digital dither signal; converting the first and second digital signals into corresponding analog dither drive signals; and applying the analog dither drive signals to the flexure to drive the flexure at its resonant frequency.
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12. A method for controlling a dither drive system for a ring laser gyroscope that includes a frame mounted to a flexure having a resonant frequency, the flexure being mounted between a base and the frame such that the frame may be dithered in an oscillatory motion relative to the base, comprising the steps of:
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forming a digital signal indicative of the dither oscillations; producing a first digital waveform that corresponds to a specified dither drive signal and frequency, the first digital waveform being in-phase with the digital signal indicative of the dither; producing a second digital waveform that corresponds to a specified dither drive signal and frequency, the second digital waveform being in quadrature with the digital signal indicative of the dither; driving the flexure with analog signals indicative of the first and second digital waveforms; demodulating the digital signal indicative of the dither oscillations with the first digital waveform to obtain an in-phase error signal; demodulating the digital signal indicative of the dither oscillations with the second digital waveform to obtain a quadrature phase error signal; and nulling the quadrature phase error signal and servoing the in-phase error signal to a predetermined reference value.
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13. A method for controlling a dither drive system for a ring laser gyroscope that includes a frame mounted to a base by flexure springs for dithering the frame about a defined sensing axis relative to the base, comprising the steps of:
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producing a dithering signal that is a measure of the dithering motion of the frame relative to the base; producing a first sinusoidal signal having a frequency substantially at a predetermined resonant frequency of the flexure and frame; producing a second sinusoidal signal in phase quadrature with and at the same frequency as the first sinusoidal signal; determining the difference in phase between the dithering signal and the first sinusoidal signal to produce an in phase error signal; determining the difference in phase between the dithering signal and the second sinusoidal signal to produce a quadrature phase error signal; and nulling the quadrature phase error signal and for servoing the in-phase error signal to a predetermined reference value. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20)
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Specification