Method for the decoupled control of the quadrature and the resonance frequency of a micro-mechanical gyroscope

• US 9,377,483 B2
• Filed: 03/17/2011
• Issued: 06/28/2016
• Est. Priority Date: 03/17/2010
• Status: Active Grant

• Current Assignee: Continental Teves AG & Co. OHG (Continental AG)
• Original Assignee: Continental Teves AG & Co. OHG (Continental AG)
• Inventors: Egretzberger, Markus, Mair, Florian, Kugi, Andreas
• Primary Examiner(s): Kwok, Helen
• Application Number:
  US13/634,301
• Publication Number:
  US 20130199263A1
• Time in Patent Office: 1,930 Days
• Field of Search: 73/13.7, 73/13.8, 73/17.7, 735/041.4, 735/041.6, 735/040.4, 735/041.2
• US Class Current: 1/1
• CPC Class Codes: G01C 19/56 Turn-sensitive devices using vibrating masses, e.g. vibratory angular rate sensors based on Coriolis forces
• CPC Class Codes: G01C 19/5726 Signal processing
• CPC Class Codes: G01C 19/5776 Signal processing not specific to any of the devices covered by groups G01C19/5607 - G01C19/5719
• CPC Class Codes: G01P 15/125 by capacitive pick-up

Abstract

A method for the precise measuring operation of a micro-mechanical rotation rate sensor, including at least one seismic mass, at least one drive device for driving the seismic mass in the primary mode (qi) and at least three trimming electrode elements which are jointly associated directly or indirectly with the seismic mass. An electric trimming voltage (_{u1, u2, u3, u4}) is set respectively between said trimming electrode elements and the seismic mass. Each of the electric trimming voltages (_{u1, u2, u3, u4}) are adjusted in accordance with a resonance frequency variable (ũ_T, Ũ_T,0), a quadrature variable (ũ_T, Ũ_T,0) and a restoring variable (ũ_S).

Claims

1. A method for the precise measuring operation of a micro-mechanical rotation rate sensor, comprising at least one seismic mass, at least one drive device for driving the seismic mass in a primary mode (q₁) and at least three trimming electrode elements which are jointly associated directly or indirectly with the seismic mass, wherein an electric trimming voltage (u₁, u₂, u₃, u₄) is applied between the at least three trimming electrode elements and the seismic mass,

wherein each of these electric trimming voltages (u₁, u₂, u₃, u₄) is set as a function of a resonance frequency manipulated variable (ũ

_T,Ũ

_T,0), a quadrature manipulated variable (ũ

_C, Ũ

_C,0) and a resetting variable (ũ

_S), the function includes calculating the square root of at least one of a sum and a difference between the resonance frequency manipulated variable (ũ

_T, Ũ

_T,0), the quadrature manipulated variable (ũ

_C, Ũ

_C,0) and the resetting variable (ũ

_S).

2. The method as claimed in claim 1, wherein the rotation rate sensor comprises at least four trimming electrode elements which are jointly associated directly or indirectly with the seismic mass, wherein a first electric trimming voltage is applied between the first trimming electrode element and the seismic mass, a second trimming voltage is applied between the second trimming electrode element and the seismic mass, a third trimming voltage is applied between the third trimming electrode element and the seismic mass, and a fourth trimming voltage is applied between the fourth trimming electrode element and the seismic mass, wherein the first trimming voltage u₁, the second trimming voltage u₂, the third trimming voltage u₃ and the fourth trimming voltage u₄ are each set substantially with the following dependence of the resonance frequency manipulated variable ũ

_T, the quadrature manipulated variable ũ

_C and the resetting variable ũ

_S;

3. The method as claimed in claim 1, wherein the trimming electrode elements are each embodied and arranged in such a way that a capacitor C₁, C₂, C₃ and C₄ is formed between a first, second, third and fourth trimming electrode element and a respectively associated mass electrode element of the associated seismic mass, with the associated trimming voltage being applied between the trimming electrode element and the mass electrode element, as follows:

4. The method as claimed in claim 3, wherein A_i, r_i, t_i, g_iand s_i, are substantially the same in all the trimming electrode element mass electrode element capacitor arrangements.

5. The method as claimed in claim 1, wherein the rotation rate sensor comprises a control arrangement with which the electric trimming voltages are adjusted, wherein a demodulated controlled variable (Y) is fed to a first controller unit, which the demodulated controlled variable (Y) is acquired, in particular, by means of demodulation from an original controlled variable (y) using two harmonic signals which are phase-shifted through 90°

with respect to one another, wherein the original controlled variable (y) represents the detected deflection of the seismic mass in the direction of secondary mode (q₂).

6. The method as claimed in claim 5, wherein the control arrangement has an output variable transformation unit in which the demodulated controlled variable (Y) is transformed dynamically as a function of a frequency difference between a primary mode frequency (ω

₁) and a secondary mode frequency (ω

₂) and at least one damping parameter (α

₂) or is transformed in a steady-state fashion into a rotation rate variable and a quadrature variable (Z, Z₀) as a function of at least one transformation constant, after which a rotation rate control error variable and a quadrature control error variable are formed therefrom, in each case with the definition of a reference variable, and subsequently the rotation rate control error variable and the quadrature control error variable are fed as input variables to the first controller unit which generates at least the quadrature manipulated variable (ũ

_C, Ũ

_C,0) and the resetting variable (ũ

_S, Ũ

_S,C) on an output side for partially decoupled quadrature suppression and resetting of the deflection of the seismic mass on the basis of a detected rotation rate.

7. The method as claimed in claim 5, wherein a control error variable is formed from the demodulated controlled variable (Y) with the definition of a control reference variable, after which the control arrangement is dynamically transformed in an output variable transformation unit the control error variable as a function of a frequency difference between a primary mode frequency (ω

₁) and a secondary mode frequency (ω

₂) and at least one damping parameter (α

₂) or is transformed in a steady-state fashion into a rotation rate control error variable and a quadrature control error variable (Z, Z₀) as a function of at least one transformation constant, after which the rotation rate control error variable and the quadrature control error variable are fed as input variables to the first controller unit which generates on an output side at least the quadrature manipulated variable (ũ

_C, Ũ

_C,0) and the resetting variable (ũ

_S, Ũ

_S,C) for partially decoupled quadrature suppression and resetting of the deflection of the seismic mass on the basis of a detected rotation rate.

8. The method as claimed in claim 1, wherein the rotation rate sensor, has a manipulated variable transformation unit, by which the trimming voltages u₁, u₂, u₃ and u₄ are made available as a function of the resonance frequency manipulated variable ũ

_T, the quadrature manipulated variable ũ

_C and the resetting variable ũ

_S in accordance with the equations

9. The method as claimed in claim 6, wherein the output variable transformation unit is configured to carry out multiplication of the demodulated controlled variable (Y), with the following transformation matrix

10. The method as claimed in claim 6, wherein the control arrangement has a frequency controller unit which makes available the resonance frequency manipulated variable (ũ

_T, Ũ

_T,0) as a function of a frequency information item or as a function of a frequency control error information item dependent thereon from the demodulated controlled variable (Y).

11. The method as claimed in claim 10, wherein a harmonic frequency identification signal (Ũ

_S,CC cos(ω

_st)) is generated in which frequency identification signal (Ũ

_S,CC cos(ω

_st)) has a frequency ω

_S which is different from the primary mode frequency (ω

₁), wherein the frequency identification signal (Ũ

_S,CC cos(ω

_st)) is superimposed on the quadrature manipulated variable (ũ

_C, Ũ

_C,0) and/or the resetting variable (ũ

_S, Ũ

_S,CO) after which the frequency information is acquired from the demodulated controlled variable (Y) after additional demodulation with the frequency ω

_s by means of the frequency difference between the primary mode frequency ω

₁)and the secondary mode frequency (ω

₂), after which at least the resonance frequency manipulated variable (ũ

_T, Ũ

_T,0) is made available by the frequency controller unit.

12. The method as claimed in claim 11, wherein after the additional demodulation with the frequency ω

_s the frequency information of the output variable transformation unit is made available, and in addition a frequency control error information item is acquired from the frequency information by means of a frequency information reference variable which is, in particular, 0 Hz, after which the frequency control error information is fed to the frequency controller unit which generates the resonance frequency manipulated variable (ũ

_T, Ũ

_T,0) therefrom.

13. The method as claimed in claim 6, wherein the harmonic frequency identification signal (Y_D) is introduced as a reference variable or superimposed on the reference variable, either upstream of the output variable transformation unit in order to generate a control error variable, or respectively downstream of the output variable transformation unit in order to generate the rotation rate control error variable and the quadrature control error variable, after which the rotation rate control error variable and the quadrature control error variable are fed as input variables to the first controller unit which generates at least the quadrature manipulated variable (ũ

_C, Ũ

_C,0,) and the resetting variable (ũ

_S, Ũ

_S,C) on the output side.

14. The method as claimed in claim 13, wherein the resetting variable (ũ

_s, Ũ

_s,c), which is subject to information of the frequency identification signal, is then demodulated with the frequency ω

_s, as a result of which the frequency information is acquired, after which the frequency information is made available to the output variable transformation unit, and in addition a frequency control error information item is acquired from the frequency information by means of a frequency information reference variable which is, in particular, 0, after which the frequency control error information is fed to the frequency controller unit, which generates the resonance frequency manipulated variable (ũ

_T, Ũ

_T,0) therefrom.

15. A micro-mechanical rotation rate sensor, comprising at least one seismic mass, at least one drive device for driving the seismic mass in a primary mode (q₁) and at least three trimming electrode elements which are jointly assigned directly or indirectly to the seismic mass, wherein an electric trimming voltage is applied between the at least three trimming electrode elements and the seismic mass, wherein the rotation rate sensor is embodied in such a way that it is suitable for carrying out the method comprising setting electric trimming voltages (u₁, u₂, u₃, u₄) as a function of a resonance frequency manipulated variable (ũ

_T, Ũ

_T,0), a quadrature manipulated variable (ũ

_C, Ũ

_C,0) and a resetting variable (ũ

_S), the function includes calculating the square root of at least one of a sum and a difference between the resonance frequency manipulated variable (ũ

_T, Ũ

_T,0), the quadrature manipulated variable (ũ

_C, Ũ

_C,0) and the resetting variable) (ũ

_S).