Operating method for a Coriolis gyro, and evaluation/control electronics which are suitable for this purpose

• US 7,805,993 B2
• Filed: 05/06/2004
• Issued: 10/05/2010
• Est. Priority Date: 05/08/2003
• Status: Active Grant

• Current Assignee: Litec-LP GmbH
• Original Assignee: Litec-LP GmbH
• Inventors: Spahlinger, Guenter
• Primary Examiner(s): Kwok; Helen C.
• Application Number:
  US10/555,737
• Publication Number:
  US 20060250194A1
• Time in Patent Office: 2,343 Days
• Field of Search: 735/040.2, 735/040.4, 735/041.2, 735/041.3, 735/041.1, 702/145
• US Class Current: 73/504.02
• CPC Class Codes: G01C 19/56 Turn-sensitive devices using vibrating masses, e.g. vibratory angular rate sensors based on Coriolis forces

Abstract

An operating method for a Coriolis gyro. Digital read signals are produced that represent a measure of the instantaneous amplitudes/frequencies of the stimulation oscillation/read oscillation of the gyro resonator. Force signals are applied to the resonator. The force signals are controlled as a function of the digital read signals so that the stimulation oscillation/read oscillation assume specific amplitudes/frequencies. The force signals are produced from quantized output signals from a pulse modulator. The modulator is fed with digital stimulation/compensation signals derived from the digital read signals.

Claims

1. An operating method for a Coriolis gyro in which

digital read signals are produced, which represent a measure of the instantaneous amplitudes/frequencies of a stimulation oscillation/read oscillation of a resonator of the Coriolis gyro, and

force signals are applied to the resonator, with the force signals being controlled as a function of the digital read signals such that the stimulation oscillation/read oscillation assume specific amplitudes/frequencies,

the force signals are produced from quantized output signals from a pulse modulator which is fed with digital stimulation/compensation signals which are derived from the digital read signals

characterized in that the quantized output signals are pulse sequences at a constant frequency.

2. A method as claimed in claim 1, characterized in that the output signals from the pulse modulator are ternary-quantized.

3. The method as claimed in claim 2, characterized in that the pulse modulator produces a first and a second output signal which are each ternary-quantized, with the first output signal being transformed to a first sequence of ternary-quantized force pulses, and the second output signal being transformed to a second sequence of ternary-quantized force pulses (S₅, S₆), with the first sequence of force pulses being that part of the force signals which is used for setting desired amplitudes/frequencies of the stimulation oscillation, and the second sequence of force pulses being that part of the force signals which is used for setting desired amplitudes/frequencies of the read oscillation.

4. The method as claimed in one of the preceding claims, characterized in that the digital read signals are produced in such a way that

an amount of electrical charge which flows to a moving center electrode on the basis of electrical fields which are produced by the force signals is measured by means of a charge amplifier,

a corresponding analog output signal from the charge amplifier is converted to a digital output signal, and

the digital read signals are determined from the output signal from the charge amplifier via signal separation, as a function of instantaneous output signal values from the pulse modulator.

5. The method as claimed in claim 4, characterized in that the digital read signals are in each case subdivided by means of a demodulation process into a normal and a quadrature component.

6. The method as claimed in claim 5, characterized in that normal and quadrature components of the digital stimulation/compensation signals are produced by means of a control process from the normal and quadrature components of the digital read signals and are fed to the pulse modulator.

7. Evaluation/control electronics for use in a Coriolis gyro, having:

a unit for production of digital read signals which represent a measure of the instantaneous amplitudes/frequencies of a stimulation oscillation/read oscillation of a resonator of the Coriolis gyro,

at least one control loop by means of which force signals are produced as a function of the digital read signals and are passed to the resonator, with the force signals being controlled such that the stimulation oscillation/read oscillation assume specific amplitudes/frequencies,

a pulse modulator which is a part of the control loop and which is fed with digital stimulation/compensation signals which are derived from the digital read signals, in which case the force signals can be produced from quantized output signals from the pulse modulator,

characterized in that the quantized output signals are pulse sequences at a constant frequency.

8. A pulse modulator for conversion of a digital complex input signal to a pulsed signal, comprising

a subtraction stage which produces a control error signal from a difference between a digital complex input signal and a feedback signal;

a signal conversion stage with a transfer function tending to infinity when a frequency of the control error signal tends to the value zero, which converts the control error signal to a control signal;

a first multiplication stage, which multiplies the control signal by a complex mixing signal oscillating at a frequency ω

₀, and thus produces at least one of a real part and an imaginary part of a control signal up-mixed by ω

₀;

a quantization stage, which quantizes the real part or the imaginary part of the control signal up-mixed by ω

₀ and thus produces the pulsed signal;

a feedback unit, which uses the pulsed signal to produce the feedback signal for the subtraction stage; and

the subtraction stage, the signal conversion stage, the first multiplication stage and the feedback unit have an in-phase signal path and a quadrature signal path.