RATE-OF-TURN SENSOR

• US 20090249875A1
• Filed: 06/14/2006
• Published: 10/08/2009
• Est. Priority Date: 07/26/2005
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Steinlechner, Siegbert
• Granted Patent: US 7,694,561 B2
• Time in Patent Office: Days
• US Class Current: 73/504.120
• CPC Class Codes: G01C 19/56 Turn-sensitive devices using vibrating masses, e.g. vibratory angular rate sensors based on Coriolis forces

Abstract

A method for operation of and simultaneous analysis of a rate-of-turn sensor, comprising an oscillator element and a Coriolis element arranged on the oscillation element is disclosed, comprising the following method steps: generation of a digital operating signal with an excitation frequency corresponding to the resonant frequency of the oscillator element, digital to analogue conversion of the digital operating signal and operation of the oscillator element with the analogue operating signal, recording a Coriolis speed of the Coriolis element occurring about a normal to both oscillation axes due to the rotation of the rate-of-turn sensor with generation of an analogue Coriolis'"'"' signal proportional to the Coriolis speed, analogue-to-digital conversion of the analogue Coriolis signal, phase-sensitive multiplication of the digital Coriolis signal with the digital operating signal to form an intermediate signal, generation of a control signal proportional to the rate of turn of the rate of-turn sensor from the intermediate signal, multiplication of the control signal with the digital operating signal to give a digital compensation signal in phase with the digital operating signal, digital-to-analogue conversion of the digital compensation signal to give an analogue compensation signal in phase with the analogue operating signal and subjecting the Coriolis element to the analogue compensation signal and output of the control signal.

Claims

1. A method for driving and simultaneously evaluating a rate-of-turn sensor composed of at least one oscillator element oscillatable along a first axis of oscillation, and of at least one Coriolis element located on the oscillator element such that it is swingable along a second axis of oscillation that is normal to the first axis of oscillation, the method comprising the steps of:

generating a digital drive signal with an excitation frequency that corresponds to a resonant frequency of the oscillator element,

performing digital-analog conversion of a digital drive signal, and driving the oscillator element with the analog drive signal,

sensing a Coriolis velocity of the Coriolis element generated by a rotation of the rate-of-turn sensor around an axis of rotation that is normal to both axes of oscillation, and generating an analog Coriolis signal that is proportional to a Coriolis velocity,

performing analog-digital conversion of the analog Coriolis signal,

in-phase multiplying the digital Coriolis signal with the digital drive signal to produce an intermediate signal,

generating a control signal based on the intermediate signal, which is proportional to the rate of turn of the rate-of-turn sensor,

multiplying the control signal with the digital drive signal to produce a digital compensation signal that is in-phase with the digital drive signal,

performing digital-analog conversion of the digital compensation signal to produce an analog compensation signal that is in-phase with the analog drive signal, and applying the analog compensation signal to the Coriolis element, and

outputting the control signal.

2. The method as recited in claim 1,

wherein,

in order to in-phase multiply the digital Coriolis signal with the digital drive signal, the digital drive signal is delivered for multiplication such that it is delayed by a time interval that is a sum of a time required to convert the digital drive to the analog drive signal, and to convert the analog Coriolis signal to the digital Coriolis signal.

3. The method as recited in one of the claims 1 or 2,

wherein,

before the control signal is generated, frequencies that exceed an excitation frequency of the drive signal are filtered out of the intermediate signal.

4. The method as recited in claim 1,

wherein

the control signal is reduced to a desired bandwidth before it is output.

5. The method as recited in claim 1,

wherein

the control signal is generated via weighted addition of the intermediate signal and an integral of the intermediate signal over time.

6. A circuit design for carrying out the method as recited in claim 1,

comprising

Means for generating a digital drive signal with an excitation frequency that corresponds to the resonant frequency of an oscillator element of a rate-of-turn sensor,

Means for carrying out digital-analog conversion of the digital drive signal to produce an analog drive signal to drive the oscillator element of the rate-of-turn sensor,

Means for sensing a Coriolis velocity of the Coriolis element generated by a rotation of the rate-of-turn sensor, and for generating an analog Coriolis signal that is proportional to the Coriolis velocity,

Means for performing analog-digital conversion of the analog Coriolis signal to produce a digital Coriolis signal,

Means for in-phase multiplying the digital drive signal with the Coriolis signal to produce an intermediate signal,

Means for generating a control signal based on the intermediate signal, which is proportional to a rate of turn of the rate-of-turn sensor,

Means for multiplying the control signal with the digital drive signal to produce a digital compensation signal that is in-phase with the digital drive signal,

Means for performing digital-analog conversion of the digital compensation signal to produce an analog compensation signal that is in-phase with the analog drive signal, and application of the analog compensation signal to the Coriolis element, and

Means for outputting the control signal.

7. The circuit design as recited in claim 6,

wherein

the means for generating a control signal that is proportional to the rate of turn of the rate-of-turn sensor include means for integrating the intermediate signal over time.

8. The circuit design as recited in claim 7,

wherein

the means for integrating the intermediate signal over time include a proportional integral controller.

9. The circuit design as recited in claim 6,

wherein

the means for in-phase multiplying the digital drive signal with the digitized Coriolis signal include a time-delay unit that delays the digital drive signal to be delivered for multiplication by a time interval that is the sum of the time required to convert the digital drive signal to the analog drive signal, and to convert the analog Coriolis signal to the digital Coriolis signal.

10. The circuit design as recited in claim 6,

wherein

a low-pass filter is located between the means for in-phase multiplying the digital drive signal with the digital Coriolis signal and the means for generating a control signal that is proportional to the rate of turn of the rate-of-turn sensor.

11. The circuit design as recited in claim 6,

wherein

the means for outputting the control signal include a low-pass filter.

12. The circuit design as recited in claim 6,

wherein

means for perform the low-pass filtering of the intermediate signal.