Angular rate detecting device

• US 6,267,008 B1
• Filed: 10/19/1999
• Issued: 07/31/2001
• Est. Priority Date: 10/23/1998
• Status: Expired due to Term

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Nagao, Masaru
• Primary Examiner(s): MOLLER, RICHARD ALAN
• Application Number:
  US09/420,464
• Time in Patent Office: 651 Days
• Field of Search: 735/041.2, 735/041.6, 735/040.2, 735/040.3, 735/040.4
• US Class Current: 73/504.12
• CPC Class Codes: G01C 19/5719 using planar vibrating masses driven in a translation vibration along an axis

Abstract

An oscillator 20 and main frames 30-1 and 30-2, coupled to one another by beams 33-1 through 33-4, float above the upper face of a substrate 10. The main frames 30-1 and 30-2 are divided into a plurality of sections along a Y-axis. Drive electrode portions 51-1 through 51-4 drive the main frames 30-1 and 30-2 and the oscillator 20 in the direction of an X-axis. Due to an angular rate around a Z-axis perpendicular to the X and Y axes, the oscillator 20 oscillates in the direction of the Y-axis. The oscillation in the direction of the Y-axis is measured using a high-frequency signal applied to detection electrode portions 53-1 through 53-4, whereby the angular rate is detected. The main frame 30-1 is provided with drive electrode portions 51-1 and 51-2, while the main frame 30-2 is provided with drive electrode portions 51-3 and 51-4. Drive signals independent from one another are supplied to the drive electrode portions 51-1 through 51-4, whereby the main frames 30-1 and 30-2 are caused to oscillate precisely in the direction of the X-axis.

Claims

1. An angular rate detecting device comprising:

an oscillation portion connected to a substrate via a supporting member and oscillatable over the substrate in directions of an X-axis and a Y-axis, the X and Y axes being perpendicular to one another;

a drive portion causing the oscillation portion to oscillate independently along the X-axis, the drive portion comprising a plurality of sectional drive portions spaced apart in the direction of the Y-axis, the sectional drive portions being capable of oscillating the oscillating portion independently in the direction of the X-axis;

a detection portion detecting oscillation of the oscillation portion with respect to the substrate in the direction of the Y-axis; and

an angular rate detector for detecting, based on oscillation of the oscillation portion in the direction of the Y-axis, an angular rate that is effective around a Z-axis, the Z axis being perpendicular to both the X-axis and the Y-axis, with the oscillation portion oscillating in the direction of the X-axis.

2. The angular rate detecting device according to claim 1, wherein the oscillation portion is composed of a frame and an oscillator connected via a beam, and wherein the sectional drive portions drive the frame with respect to the substrate in the direction of the X-axis and cause the oscillator to oscillate with respect to the substrate in the direction of the X-axis, and wherein the detection portion detects oscillation of the oscillator with respect to the substrate in the direction of the Y-axis.

3. The angular rate detecting device according to claim 2, wherein independent drive signals are supplied to each of the sectional drive portions, and wherein the device further comprises a drive signal generation circuit for varying a driving force resulting from at least one of the drive signals.

4. The angular rate detecting device according to claim 2, wherein each of the sectional drive portions is composed of a pair of drive electrodes disposed on a line extending in the direction of the X-axis.

5. The angular rate detecting device according to claim 4, further comprising a drive signal generation circuit supplying a respective set of drive signals to each of the sectional drive portions, with each of the sectional drive signals corresponding to the pair of drive electrodes that constitute the sectional drive portions, the drive signal generation circuit setting the respective sets of drive signals opposite in phase and making a driving force resulting from at least one of the sets of drive signals variable.

6. The angular rate detecting device according to claim 1, wherein drive signals are supplied to the sectional drive portions, wherein the drive signals are independent from one another, and wherein the device comprises a drive signal generation circuit for making a driving force resulting from at least one of the drive signals variable.

7. The angular rate detecting device according to claim 1, wherein each of the sectional drive portions is composed of a pair of drive electrodes disposed on a line extending in the direction of the X-axis.

8. The angular rate detecting device according to claim 7, further comprising a drive signal generation circuit for supplying a respective set of drive signals to each of the sectional drive portions with each set of drive signals corresponding to a respective pair of drive electrodes constituting the corresponding sectional drive portion, the drive signal generation circuit setting the respective sets of drive signals opposite in phase and making a driving force resulting from at least one of the sets of drive signals variable.

9. An angular rate detecting device comprising:

a frame connected to a substrate through a driving beam and oscillatable with respect to the substrate in a direction of an X-axis, the frame being divided into a plurality of sections;

an oscillator connected to an inside of the frame via the driving beam and supported oscillatably with respect to the substrate in the direction of the X-axis and in a direction of a Y-axis, the Y-axis being perpendicular to the X-axis;

a drive portion causing the frame to oscillate with respect to the substrate in the direction of the X-axis;

a detection portion detecting oscillation of the oscillator with respect to the substrate in the direction of the Y-axis; and

an angular rate detector for detecting, based on oscillation of the oscillation portion in the direction of the Y-axis, an angular rate effective around a Z-axis, the Z-axis being perpendicular to both the X-axis and the Y-axis, wherein the flame and the oscillator oscillates in the direction of the X-axis.

10. The angular rate detecting device according to claim 9, wherein the frame comprises a main frame having a portion extending in the direction of the X-axis, the main frame being connected to the oscillator via the detecting beam and a sub-frame extending parallel to a portion of the main frame extending in the direction of the X-axis, and wherein the driving beam comprises first and second driving beams, the first driving beam connecting the substrate with the sub-frame and supporting the sub-frame oscillatably with respect to the substrate in the direction of the X-axis, the second driving beam connecting the sub-frame with the main frame and supporting the main frame oscillatably with respect to the substrate in the direction of the X-axis.

11. An angular rate detecting device comprising:

a frame connected to a substrate via a driving beam, the frame being oscillatable with respect to the substrate in a direction of an X-axis, the driving beam comprising a pair of drive beams disposed symmetrically with respect to a central position of the frame in the direction of the X-axis and at least another drive beam provided between the pair of the drive beams;

an oscillator connected to an inside of the frame and supported oscillatably with respect to the substrate in the direction of the X-axis and in a direction of a Y-axis, the Y-axis being perpendicular to the X-axis;

a drive portion causing the frame to oscillate with respect to the substrate in the direction of the X-axis;

a detection portion detecting oscillation of the oscillator with respect to the substrate in the direction of the Y-axis; and

an angular rate detector detecting, based on oscillation of the oscillation portion in the direction of the Y-axis, an angular rate effective around a Z-axis, the Z-axis being perpendicular to both the X-axis and the Y-axis, wherein the flame and the oscillator oscillates in the direction of the X-axis.

12. The angular rate detecting device according to claim 11, wherein the frame comprises a main frame and a sub-frame, the main frame having a portion extending in the direction of the X-axis and being connected to the oscillator through the detecting beam, and wherein the sub-frame extends parallel to the portion of the main frame extending in the direction of the X-axis, and wherein the driving beam comprises first and second driving beams, the first driving beam connecting the substrate to the sub-frame and supporting the sub-frame oscillatably with respect to the substrate in the direction of the X-axis, the second driving beam connecting the sub-frame to the main frame and supporting the main frame oscillatably with respect to the substrate in the direction of the X-axis.

13. An angular rate detecting device comprising:

a frame connected to a substrate via a driving beam and oscillatable with respect to the substrate in a direction of an X-axis;

an oscillator connected to the frame via the driving beam and supported oscillatably with respect to the substrate;

a drive portion causing the frame to oscillate with respect to the substrate in the direction of the X-axis;

a detection portion detecting oscillation of the oscillator with respect to the substrate in a direction of a Y-axis, the Y-axis being perpendicular to the X-axis;

an angular rate detector detecting, based on oscillation of the oscillator in the direction of the Y-axis, an angular rate effective around a Z-axis, the Z-axis being perpendicular to both the X-axis and the Y-axis, wherein the flame and the oscillator oscillates in the direction of the X-axis; and

a correction portion retrieving an oscillation component of the frame with respect to the substrate in the direction of the Y-axis.

14. The angular rate detecting device according to claim 13, wherein the driving beam supports the frame so that the frame oscillates with respect to the substrate more easily in the direction of the X-axis than in the direction of the Y-axis, and wherein a detecting beam is connected to the frame so that the oscillator oscillates with respect to the substrate more easily in the direction of the Y-axis than in the direction of the X-axis.

15. The angular rate detecting device according to claim 14, wherein the detection portion is electrically connected to the correction portion, and wherein the oscillation component of the frame in the direction of the Y-axis retrieved by the correction portion is removed from the oscillation component of the oscillator in the direction of the Y-axis detected by the detection portion.

16. The angular rate detecting device according to claim 14, further comprising an arithmetic circuit removing the oscillation component of the frame in the direction of the Y-axis retrieved by the correction portion from the oscillation component of the oscillator in the direction of the Y-axis detected by the detection portion.

17. The angular rate detecting device according to claim 13, wherein the detection portion is electrically connected to the correction portion, and the oscillation component of the frame in the direction of the Y-axis retrieved by the correction portion is removed from the oscillation component of the oscillator in the direction of the Y-axis detected by the detection portion.

18. The angular rate detecting device according to claim 13, further comprising an arithmetic circuit for removing the oscillation component of the frame in the direction of the Y-axis retrieved by the correction portion from the oscillation component of the oscillator in the direction of the Y-axis detected by the detection portion.

19. An angular rate detecting device comprising:

an oscillation portion connected to a substrate via a supporting member, the oscillation portion being oscillatable over the substrate in directions of an X-axis and a Y-axis, the X-axis and the Y-axis being perpendicular to one another;

a drive portion causing the oscillation portion to oscillate with respect to the substrate in the direction of the X-axis;

a detection portion detecting oscillation of the oscillation portion with respect to the substrate in the direction of the Y-axis;

an angular rate detector detecting, based on oscillation of the oscillation portion in the direction of the Y-axis, an angular rate effective around a Z-axis, the Z-axis being perpendicular to both the X-axis and the Y-axis, wherein the oscillation portion oscillates in the direction of the X-axis;

a servo portion restraining oscillation of the oscillation portion in the direction of the Y-axis;

a drive circuit causing the oscillation portion to oscillate with respect to the substrate in the direction of the X-axis with a predetermined amplitude, in cooperation with the drive portion;

a retrieval circuit retrieving a signal indicative of oscillation of the oscillation portion with respect to the substrate in the direction of the Y-axis, in cooperation with the detection portion;

a servo control circuit forming a servo control signal, based on the retrieved signal indicative of oscillation of the oscillation portion in the direction of the Y-axis, the servo control signal being supplied to the servo portion to restrain oscillation of the oscillation portion in the direction of the Y-axis; and

an output circuit outputting a signal corresponding to the formed servo control signal as a signal indicative of the angular rate.

20. The angular rate detecting device according to claim 19, wherein the servo control circuit comprises a servo signal supplying circuit for receiving the retrieved signal indicative of oscillation of the oscillation portion in the direction of the Y-axis and supplying the servo portion with the servo control signal, wherein the servo control signal is an AC signal, and wherein the output circuit comprises a DC-conversion circuit for converting the AC servo control signal into a DC signal proportional to an amplitude of the AC servo control signal.

21. The angular rate detecting device according to claim 20, further comprising an abnormality judging circuit coupled to a downstream side of a path of a signal indicative of oscillation of the oscillation portion in the direction of the Y-axis, the abnormality judging circuit supplying an upstream portion of the path with a dummy signal of a predetermined frequency, superposes the dummy signal onto the signal indicative of oscillation of the oscillation portion in the direction of the Y-axis, and judges whether there is an abnormality in the path, based on whether the dummy signal is received.

22. The angular rate detecting device according to claim 19, wherein the servo control circuit comprises a reference signal forming circuit connected to the drive circuit, the reference signal forming circuit forming a reference signal having a predetermined amplitude and corresponding to a phase of oscillation of the oscillation portion resulting from an angular rate, the servo control circuit further including a DC-conversion circuit and a servo signal supplying circuit, the DC-conversion circuit converting the retrieved signal indicative of oscillation of the oscillation portion in the direction of the Y-axis into the servo control signal proportional to an amplitude value of the retrieved signal, the servo control signal output by the DC-conversion circuit being a DC signal, and wherein the servo signal supplying circuit controls the amplitude of the reference signal in accordance with the DC servo control signal and supplies the servo portion with the amplitude-controlled reference signal to restrain oscillation of the oscillation portion in the direction of the Y-axis, and wherein the output circuit outputs the DC servo control signal as a signal indicative of the angular rate.

23. The angular rate detecting device according to claim 22, further comprising an abnormality judging circuit coupled to a downstream side of a path of a signal indicative of oscillation of the oscillation portion in the direction of the Y-axis, the abnormality judging circuit supplying an upstream portion of the path with a dummy signal of a predetermined frequency, wherein the abnormality judging circuit superposes the dummy signal onto the signal indicative of oscillation of the oscillation portion in the direction of the Y-axis and judges whether or not there is an abnormality in the path based on whether the dummy signal is received.

24. The angular rate detecting device according to claim 19, further comprising an abnormality judging circuit coupled to a downstream side of a path of a signal indicative of oscillation of the oscillation portion in the direction of the Y-axis, the abnormality judging circuit supplying an upstream portion of the path with a dummy signal of a predetermined frequency, wherein the abnormality judging circuit superposes the dummy signal onto the signal indicative of oscillation of the oscillation portion in the direction of the Y-axis and judges whether there is an abnormality in the path based on whether the dummy signal is received.

25. An angular rate detecting device comprising:

an oscillation portion connected to a substrate via a supporting member, the oscillation portion being oscillatable over the substrate along an X-axis and a Y-axis, the X and Y axes being perpendicular to one another;

a drive portion causing the oscillation portion to oscillate with respect to the substrate in the direction of the X-axis;

a detection portion detecting oscillation of the oscillation portion with respect to the substrate in the direction of the Y-axis;

an angular rate detector for detecting, based on oscillation of the oscillation portion in the direction of the Y-axis, an angular rate effective around a Z-axis, the Z-axis being perpendicular to both the X-axis and the Y-axis, wherein the oscillation portion oscillates in the direction of the X-axis;

a servo portion restraining oscillation of the oscillation portion in the direction of the Y-axis;

a drive circuit causing the oscillation portion to oscillate with respect to the substrate in the direction of the X-axis with a predetermined amplitude, in cooperation with the drive portion;

a retrieval circuit retrieving a signal indicative of oscillation of the oscillation portion with respect to the substrate in the direction of the Y-axis, in cooperation with the detection portion;

a first servo control circuit forming a first servo control signal, based on the signal inputted from the retrieval circuit indicating oscillation of the oscillation portion in the direction of the Y-axis and a signal inputted from the drive circuit synchronous with oscillation of the oscillation portion caused by the angular rate, the first servo control signal being outputted to the servo portion to restrain oscillation of the oscillation portion in the direction of the Y-axis;

a second servo control circuit forming a second servo control signal, based on the signal that is inputted from the retrieval circuit and indicates oscillation of the oscillation portion in the direction of the Y-axis and a signal that is inputted from the drive circuit and is synchronous with the cross talk of the oscillation portion in the direction of the Y-axis caused by the driving thereof, the second servo control signal being supplied to the servo portion to restrain cross talk; and

an output circuit outputting a signal corresponding to the first servo control signal as a signal indicative of the angular rate.

26. The angular rate detecting device according to claim 25, wherein:

the first servo control circuit comprises;

a first reference signal forming circuit controlling the amplitude of the signal inputted from the drive circuit synchronous with oscillation of the oscillation portion caused by the angular rate and forming a first reference signal of a predetermined amplitude;

a first synchronous detection circuit synchronously detecting the retrieved signal indicative of oscillation of the oscillation portion in the direction of the Y-axis with the signal inputted from the drive circuit synchronous with oscillation of the oscillation portion caused by the angular rate, the first synchronous detection circuit forming the first servo control signal proportional to a magnitude of oscillation of the oscillation portion in the direction of the Y-axis caused by the angular rate; and

a first servo control signal supplying circuit controlling the amplitude of the first reference signal in accordance with the first servo control signal and supplying the servo portion with the amplitude-controlled first reference signal to restrain oscillation of the oscillation portion in the direction of the Y-axis caused by the angular rate, and wherein the second servo control circuit comprises;

a second reference signal forming circuit controlling the amplitude of the signal inputted from the drive circuit synchronous with cross talk of the oscillation portion caused by the driving thereof, the second reference signal forming circuit forming a second reference signal of a predetermined amplitude;

a second synchronous detection circuit synchronously detecting the retrieved signal indicative of oscillation of the oscillation portion in the direction of the Y-axis with the signal inputted from the drive circuit synchronous with cross talk of the oscillation portion caused by the driving thereof, wherein the second synchronous detection circuit forms a second servo control signal proportional to the magnitude of oscillation of the oscillation portion in the direction of the Y-axis caused by the driving thereof; and

a second servo control signal supplying circuit controlling the amplitude of the second reference signal in accordance with the second servo control signal and supplying the servo portion with the amplitude-controlled second reference signal to restrain oscillation of the oscillation portion in the direction of the Y-axis caused by the driving thereof, and wherein the output circuit outputs the first servo control signal as a signal indicative of the angular rate.

27. The angular rate detecting device according to claim 26, further comprising an abnormality judging circuit coupled to a downstream side of a path of a signal indicative of oscillation of the oscillation portion in the direction of the Y-axis, the abnormality judging circuit supplying an upstream portion of the path with a dummy signal of a predetermined frequency, wherein the abnormality judging circuit superposes the dummy signal onto the signal indicative of oscillation of the oscillation portion in the direction of the Y-axis and judges whether there is an abnormality in the path based on whether the dummy signal is received.

28. The angular rate detecting device according to claim 25, further comprising an abnormality judging circuit coupled to a downstream side of a path of a signal indicative of oscillation of the oscillation portion in the direction of the Y-axis, the abnormality judging circuit supplying an upstream portion of the path with a dummy signal of a predetermined frequency, wherein the abnormality judging circuit superposes the dummy signal onto the signal indicative of oscillation of the oscillation portion in the direction of the Y-axis and judges whether there is an abnormality in the path based on whether the dummy signal is received.

29. An angular rate detecting device comprising:

an oscillation portion connected to a substrate via a supporting member, the oscillation portion being oscillatable over the substrate in directions of an X-axis and a Y-axis, the X and Y axes being perpendicular to one another;

a drive portion causing the oscillation portion to oscillate with respect to the substrate in the direction of the X-axis;

a detection portion detecting oscillation of the oscillation portion with respect to the substrate in the direction of the Y-axis;

an angular rate detector detecting, based on oscillation of the oscillation portion in the direction of the Y-axis, an angular rate effective around a Z-axis, the Z-axis being perpendicular to both the X and Y axes, wherein the oscillation portion oscillates in the direction of the X-axis;

a servo portion restraining oscillation of the oscillation portion in the direction of the Y-axis;

a drive circuit causing the oscillation portion to oscillate with respect to the substrate in the direction of the X-axis with a predetermined amplitude, in cooperation with the drive portion;

a retrieval circuit for retrieving a signal indicative of oscillation of the oscillation portion with respect to the substrate in the direction of the Y-axis, in cooperation with the detection portion;

a first servo control circuit inputting from the drive circuit a signal synchronous with oscillation of the oscillation portion caused by the angular rate, and inputting from the retrieval circuit a signal indicative of oscillation of the oscillation portion in the direction of the Y-axis, wherein, based on the inputted signals, the first servo control circuit forms a first servo control signal restraining oscillation of the oscillation portion in the direction of the Y-axis in accordance with the angular rate and supplies the first servo control signal to the servo portion to restrain oscillation of the oscillation portion in the direction of the Y-axis in accordance with the angular rate;

a second servo control circuit inputting from the drive circuit a signal different in phase from the signal that is synchronous with oscillation of the oscillation portion caused by the angular rate, and inputting from the retrieval circuit a detection signal indicative of oscillation of the oscillation portion in the direction of the Y-axis, forming a second servo control signal which restrains an oscillation component of the oscillation portion in the direction of the Y-axis which component is synchronous with the signal different in phase, wherein the second servo control circuit supplies the formed second servo control signal to the servo portion to restrain the oscillation component of the oscillation portion in the direction of the Y-axis which component is synchronous with the signal different in phase; and

an output circuit for outputting a signal corresponding to the first servo control signal as a signal indicative of the angular rate.

30. The angular rate detecting device according to claim 29, wherein the signal different in phase is different by 90 degree from the phase of the signal synchronous with the oscillation caused by the angular rate.

31. The angular rate detecting device according to claim 30, further comprising an abnormality judging circuit coupled to a downstream side of a path of a signal indicative of oscillation of the oscillation portion in the direction of the Y-axis, the abnormality judging circuit supplying an upstream portion of the path with a dummy signal of a predetermined frequency, wherein the abnormality judging circuit superposes the dummy signal onto the signal indicative of oscillation of the oscillation portion in the direction of the Y-axis and judges whether there is an abnormality in the path based on whether the dummy signal is received.

32. The angular rate detecting device according to claim 29, further comprising an abnormality judging circuit coupled to a downstream side of a path of a signal indicative of oscillation of the oscillation portion in the direction of the Y-axis, the abnormality judging circuit supplying an upstream portion of the path with a dummy signal of a predetermined frequency, wherein the abnormality judging circuit superposes the dummy signal onto the signal indicative of oscillation of the oscillation portion in the direction of the Y-axis and judges whether there is an abnormality in the path, based on whether the dummy signal is received.