US 4,951,508 A · Vibratory rotation sensor

Abstract

A vibratory rotation sensor includes a heimspherical resonator, a ring forcer electrode and a plurality of discrete forcer and pick-off electrodes. A vibratory or flexural standing wave pattern is established in the resonator and signals from the pick-off electrodes are combined to produce first (E.sub.c) and second (E.sub.s) signals that represent two independent components of the vibration pattern. A reference phase generator generates timing signal that are used to demodulate E.sub.c and E.sub.s to obtain in-phase and quadrature components thereof. The quadrature components are transformed in a computer to generate nodal and antinodal quadrature signals. The nodal quadrature signal is used as the error signal in a quadrature control loop that keeps both components of the vibration pattern in phase. The antinodal quadrature signal is used as the error signal in a phase-locked loop that keeps the phase of the reference phase generator locked to the phase of the vibration.

Claims11

Dependent claims

A vibratory rotation sensor comprising a resonator capable of sustaining a flexural standing wave pattern symmetrically distributed about an input axis, means supporting said resonator along said input axis, means for maintaining the amplitude of said pattern in said resonator, pick-off means responsive to resonator motion for producing first and second pick-off signals proportional to two components of pattern flexure, means for generating timing signals, means responsive to the said first and second pick-off signals and said timing signals for producing a signal proportional to a readout angle .THETA., means responsive to said first and second pick-off signals and said timing signals for obtaining the quadrature component (cos quad) of said first pick-off signal relative to said timing signals and the quadrature component (sin quad) of said second pick-off signals relative to said timing signals, means responsive to said quadrature components and said readout angle .THETA. for obtaining an antinodal quadrature signal equal to ((cos quad)cos 2.THETA.+(sin quad)sin 2.THETA.), a phase locked loop responsive to said antinodal quadrature signal for regulating said timing signals by driving said antinodal quadrature signal to zero to thereby keep the phase of the timing signals locked to the phase of the antinodal component of the standing wave pattern.

A vibratory rotation sensor comprising a resonator capable of sustaining a flexural standing wave pattern symmetrically distributed about an input axis, means supporting said resonator along said input axis, forcer means for initiating said pattern in said resonator and including a plurality of discrete forcer electrodes defining first and second axis sets displaced one from the other by a predetermined number degrees, pick-off means responsive to resonator motion for producing first(E.sub.c) and second(E.sub.s) pick-off signals proportional to two components of pattern flexure, means for generating timing signals, pattern angle readout means responsive to the said first and second pick-off signals and said timing signals for producing a readout angle .THETA., quadrature detector means responsive to said first and second pick-off signals and said timing signals for obtaining the quadrature component(cos quad) of said first pick-off signal relative to said timing signals and the quadrature component(sin quad) of said second pick-off signals relative to said timing signals, coordinate transformation means responsive to said quadrature components and said readout angle .THETA. for obtaining an antinodal quadrature signal equal to ((cos quad)cos 2.THETA.+(sin quad)sin 2.THETA.) and a nodal quadrature signal equal to ((cos quad)sin2.THETA.-(sin quad)cos 2.THETA.), phase locked loop means responsive to said antinodal quadrature signal for regulating said timing signals by driving said antinodal quadrature signal to zero to thereby keep the phase of the timing signals locked to the phase of the antinodal component of the standing wave pattern, means responsive to said nodal quadrature signal for generating a nodal quadrature error signal, means providing a calibration error signal, and means for distributing said nodal quadrature error signal and said calibration error signal along said first and second axis sets to drive said nodal quadrature signal to zero and thereby keep the components of the pattern in phase.

A vibratory rotation sensor comprising a resonator capable of sustaining a flexural standing wave pattern symmetrically distributed about an input axis, means supporting said resonator along said input axis, forcer means including a circular forcer electrode and first, second, third and fourth sets of discrete orthogonal forcer electrodes, means including said discrete forcer electrodes for initiating said pattern in said resonator means including said circular electrode controlling the amplitude of flexure of said pattern, said first and second sets of discrete forcer electrodes displaced one from the other by 45 degrees and defining first and second axis sets, said third and fourth sets of discrete forcer electrodes displaced one from the other by 45 degrees and defining third and fourth axis sets interposed between said first and second axis sets, pick-off means responsive to resonator motion along said first and second axis sets and including first and second sets of discrete orthogonal pick-off electrodes, said pick-off means producing first and second pick-off signals (E.sub.c,E.sub.s) that represent the vibration pattern components along said first and second axis sets, reference generator means for generating timing signals, angle readout means responsive to the said first and second pick-off signals and said timing signals for producing a signal proportional to a readout angle .THETA., means responsive to said first and second pick-off signals and said timing signal for obtaining the quadrature component(cos quad) of said first pick-off signal relative to said timing signals and the quadrature component(sin quad) of said second pick-off signals relative to said timing signals, means responsive to said quadrature components and said readout angle .THETA. for obtaining an antinodal quadrature signal equal to ((cos quad)cos 2.THETA.+(sin quad)sin 2.THETA.), phase locked loop means responsive to said antinodal quadrature signal for regulating said timing signals by driving said antinodal quadrature signal to zero to thereby keep the phase of the timing signals locked to the phase of the antinodal component of the standing wave pattern, means responsive to said nodal quadrature signal for generating a nodal quadrature error signal, means providing a calibration error signal, and means for distributing said nodal quadrature error signal and said calibration error signal along said first or second axis sets and said third or fourth axis sets to drive said nodal quadrature signal to zero and thereby keep the components of the pattern in phase.

A vibratory rotation sensor comprising a resonator capable of sustaining a flexural standing wave pattern symmetrically distributed about an input axis,

means supporting said resonator along said input axis,
means for generating timing signals,
pick-off means responsive to resonator motion for producing first and second pick-off signals proportional to two components of pattern flexure,
first forcer means responsive to said first and second pickoff signals and said timing signals for controlling the amplitude of resonator flexure,
pattern angle detecting means responsive to the said first and second pick-off signals and said timing signals for providing a signal proportional to any vibration pattern rotation angle .THETA. with respect to a reference location,
detector means responsive to said first and second pick-off signals and said timing signals for obtaining the quadrature component(cos quad) of said first pick-off signal relative to said timing signals and the quadrature component(sin quad) of said second pick-off signals relative to said timing signals,
means performing a coordinate transformation of said quadrature components to obtain an antinodal quadrature signal equal to ((cos quad)cos 2.THETA.+(sin quad)sin 2.THETA.) and a nodal quadrature signal equal to ((cos quad) sin 2.THETA.-(sin quad)cos 2.THETA.),
phase locked loop means responsive to said antinodal quadrature signal for keeping the phase of the timing signals locked to the phase of the antinodal component of the standing wave pattern,
second forcer means comprising first, second, third and fourth sets of forcer electrodes separated by 22.5 degrees, each set of forcer electrodes comprising four discrete electrodes,
resonator quadrature control means responsive to said nodal quadrature signal for applying voltages to said first or second and said third or fourth sets of forcer electrodes to maintain said components of pattern flexure in phase and minimize the drift sensitivity to quadrature motion.

7 more elements

Dependencies are inferred from the claim text.

Vibratory rotation sensor

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Vibratory rotation sensor

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Abstract

Claims11