JP4924858B2 - Angular velocity measuring device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an angular velocity measuring device and method for detecting the rotational angular velocity of a rotation applied to a vibrator, and a diagnostic circuit for use in the same.
[0002]
[Prior art]
The applicant has been studying various applications of the vibratory gyroscope. For example, the applicant has examined the use of the vibratory gyroscope as a rotational speed sensor used in a vehicle control method of a vehicle body rotational speed feedback type of an automobile. In such a system, the direction of the steering wheel itself is detected by the rotation angle of the steering wheel. At the same time, the rotational speed at which the vehicle body is actually rotating is detected by the vibration gyroscope. Then, the direction of the steering wheel is compared with the actual rotational speed of the vehicle body to obtain a difference, and based on this difference, correction is made to the wheel torque and the steering angle, thereby realizing stable vehicle body control. In Japanese Patent Application Laid-Open No. 11-281372, the present applicant has proposed a vibratory gyroscope suitable for a horizontal type using a vibrator mainly extending in a plane.
[0003]
Such a vibratory gyroscope is used to grasp the behavior of the vehicle body. Grasping the behavior of the vehicle body is necessary for a system for preventing disturbance of the vehicle body behavior such as side slip and spin of the vehicle. Further, it is necessary to construct a system for keeping the inter-vehicle distances of a plurality of vehicles constant. In such a system, if the vibration type gyroscope breaks down, incorrect information about the position of the vehicle body is output, incorrect control is performed, and the behavior of the vehicle body may become unstable. For this reason, a system for detecting a failure of the vibration type gyroscope is required.
[0004]
The following two methods are known for detecting a failure of the vibration type gyroscope.
(1) The angular velocity of the vehicle is estimated from the vehicle speed, the steering angle, and the acceleration information in the lateral direction of the vehicle body. This estimated value is compared with the measured value of the angular velocity output from the vibrating gyroscope. When the deviation between the estimated value and the actually measured value becomes large, it is estimated that the vibration gyroscope has failed and is output.
(2) A fault diagnosis circuit is built in the vibration gyro sensor, the vibrator is oscillated by a self-excited oscillation circuit, and the vibration state of the vibrator is monitored.
[0005]
[Problems to be solved by the invention]
However, in the method (1), when the shape of the road is peculiar, such as a road having a bank angle, even if the angular velocity is estimated from the vehicle speed, the steering angle, and the acceleration information in the lateral direction of the vehicle body, The error from the angular velocity may increase.
[0006]
In the method (2), when an abnormality occurs in the oscillation state of the vibrator, it can be detected. However, it has been found that the following problems occur when actually controlling the position of the vehicle. For example, when performing control to keep the inter-vehicle distance between the preceding vehicle and the following vehicle constant, if the inter-vehicle distance deviates from a specified value, it responds in a short time and performs precise control smoothly and smoothly. It is essential. If such a quick and smooth control is not performed, the vehicle occupant is uncomfortable and uneasy.
[0007]
However, from this point of view, it has been found that the conventional failure diagnosis method of detecting when an abnormality occurs in the oscillation state of the vibrator is insufficient. That is, during actual vehicle travel, even if the oscillation state of the vibrator is normal, the angular velocity value calculated from the actual detection signal may deviate significantly from the actual angular velocity. In such a case, no fault is output from the fault diagnosis circuit of the vibration gyroscope. For this reason, the actual vehicle position deviates from the calculated value of the vehicle position based on the vibration gyroscope. For this reason, even though control is actually required, there is no output indicating that a failure has been detected from the failure diagnosis circuit of the vibratory gyroscope, so it is possible to quickly determine whether or not to perform control. Can not. Even if the necessary control is finally performed, a standby time for determining the correctness of the control is required, and the control start is considerably delayed. As a result, quick and smooth control is not performed with a short response time, and the inter-vehicle distance may be left with a large deviation from the specified value, which may cause discomfort and anxiety to the vehicle occupant.
[0008]
An object of the present invention is to provide an angular velocity measuring device for measuring the angular velocity of rotation applied to a vibrator, and when failure occurs during operation of the device, failure detection is performed at an early stage and standby for determining whether or not there is a failure. It is to be able to shorten the time.
[0009]
[Means for Solving the Problems]
The present invention is an angular velocity measuring device for measuring the angular velocity of rotation applied to a vibrator,
A vibrator, a drive circuit for exciting drive vibration in the vibrator, a detection signal output circuit for processing an output signal from the vibrator and obtaining a detection signal corresponding to the angular velocity, and a detection signal output circuit And a diagnostic circuit for diagnosing the function.
[0010]
Further, the present invention is an angular velocity measuring method for measuring the angular velocity of rotation applied to a vibrator,
A drive vibration is excited in the vibrator, an output signal from the vibrator is processed by a detection signal output circuit, and a detection signal corresponding to the angular velocity is obtained to diagnose the function of the detection signal output circuit.
[0011]
In particular, the present invention is an angular velocity measuring device for measuring the angular velocity of rotation applied to a vibrator.
[0012]
The apparatus includes a vibrator, a drive circuit for exciting drive vibration to the vibrator, a detection signal output circuit for processing an output signal from the vibrator and obtaining a detection signal corresponding to the angular velocity, and A diagnostic circuit for diagnosing the function of the detection signal output circuit is provided .
[0013]
The output signal includes a drive signal capacitive coupling component having the same frequency as the drive vibration generated in the vibrator based on the detection signal and the drive vibration, and a plurality of the output signals are output from the vibrator, The diagnostic circuit includes a capacitive coupling component output circuit that processes the output signal and outputs the drive signal capacitive coupling component after signal processing, and the capacitive coupling component output circuit includes the plurality of the capacitive coupling component output circuits from the vibrator. Are added to each other so as to cancel out detection signals in opposite phases contained in the plurality of output signals and amplify the drive signal capacitance coupling component. The detection signal output circuit is diagnosed by detecting a coupling component by detecting it with a phase shift signal based on a drive signal for obtaining the detection signal.
[0014]
The present inventor has made a diagnosis for diagnosing the function of a detection signal output circuit that is conventionally overlooked when the vibratory gyroscope is operated in a moving body such as a vehicle and the position of the moving body is to be controlled. It has been found that by providing a circuit, when a failure occurs during operation of the apparatus, failure detection can be performed at an early stage and the standby time for determining the presence or absence of the failure can be shortened. Such an error due to failure or malfunction of the detection signal output circuit cannot be grasped by detecting an oscillation state of the vibrator or an abnormality in the vibration state.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
The detection signal output circuit is a circuit that receives the raw output signal output from the vibrator and performs the following processing. The detection signal output circuit referred to in the present invention indicates the entire detection system that performs the following processing.
(1) The output signal is processed to remove or reduce noise signal components other than the predetermined detection signal corresponding to the angular velocity.
(2) Amplifying a detection signal corresponding to the angular velocity from the output signal.
[0016]
The diagnostic circuit means a circuit for diagnosing a function in the detection signal output circuit. Here, diagnosing a function in the detection signal output circuit means detecting and outputting an abnormality, malfunction, malfunction, or malfunction in at least one functional part of the detection signal output circuit.
[0017]
In a preferred embodiment, the detection signal output circuit includes an AC amplifier that amplifies the output signal (AC signal) from the vibrator, a detector that detects the signal after AC amplification, and a detection output from the detector that is DC. A rectifier that converts the signal into a signal and a DC amplifier that amplifies the DC signal are provided. Preferably, a low-pass filter that removes unnecessary high-frequency signal components from the detection output is used.
[0018]
FIG. 1 is a block diagram of a reference apparatus. The vibrator is provided with predetermined drive means 3 and, for example, two detection means 4A and 4B. Reference numeral 1 denotes a drive vibration portion, and 2A and 2B denote detection vibration portions. An external self-excited oscillation circuit 8 is connected to the driving means 3.
[0019]
At startup, noise is input from the startup circuit to the self-excited oscillation circuit 8. This noise passes through the vibrator drive unit 1 and is subjected to frequency selection, and then input to the AC amplifier 5 to be amplified. A part of the output signal from the AC amplifier 5 is taken out and input to a rectifier, and converted into an amplitude level (size). A signal having this amplitude is input to the amplitude control amplifier 6. The self-excited oscillation device 8 is connected to a diagnostic circuit (voltage comparator) 7A, and the output of the diagnostic circuit 7A is output to the outside through the DIAG terminal 16A.
[0020]
The detection system of this example includes a detection signal output circuit 20B and a comparison signal output circuit 20A. The detection signal output circuit is a circuit for processing the output signal of the vibrator and extracting a genuine detection signal. Output signals from the vibrators 2A and 2B are detected by the detection means 4A and 4B, and amplified by the preamplifiers 10A and 10B. Each output from each amplifier 10A, 10B includes at least a true detection signal corresponding to the angular velocity. In this example, each detection signal included in each output signal has an opposite phase. Accordingly, each output signal is input to the subtractor 11 and subtracted, leaving a genuine detection signal. Next, the output from the subtractor 11 is passed through the AC amplifier 12B, the detector 13B, the low-pass filter 14B, and the limiter 15B, and a detection signal is obtained from the terminal 16C.
[0021]
Here, in this example, the detector 13B detects the output signal using a phase shift signal based on the drive signal. That is, the output signal from the output signal includes a leakage signal in addition to the genuine detection signal. The derived signal is branched from the drive signal. The derived signal has the same frequency and phase as the drive signal that is the source. The authentic detection signal should have the same frequency as the derived signal and be 90 ° out of phase with the derived signal. This is because the vibrator uses the Coriolis force to detect the rotational angular velocity.
[0022]
On the other hand, the drive vibration caused in the vibrator by the drive signal is propagated mechanically as it is to the detection means 4A and 4B, and a leak signal is generated in the output signal from the detection means. . The phase of the leakage signal is the same as the phase of the drive signal that is the source of the leakage signal.
[0023]
Therefore, the phase of the phase shift signal should be 90 ° out of phase with the leakage signal. Therefore, the derived signal from the drive vibration is passed through the phase shifter 9 to shift the phase by, for example, 90 ° to obtain a phase shift signal. When the phase shift signal is input to the detection circuit 13B and the output signal is detected, an unnecessary leakage signal is erased from the detection output, and a genuine detection signal should be obtained. This detection signal is input to the smoothing circuit, and the output is amplified.
[0024]
In this reference example , a comparison signal output circuit 20A is provided in addition to the detection signal output circuit 20B. The circuit 20A has substantially the same specifications as the circuit 20B, and includes an AC amplifier 12A, a detector 13A, and a low-pass filter 14A. These operations are the same as those of the detection signal output circuit 20B described above. And the output of 15A and the output of 15B are compared in the comparison apparatus 7B, and a comparison result is taken out from the terminal 16B.
Note that the voltage comparator may be other comparing means for comparing other electrical characteristics.
[0025]
When the detection signal output circuit 20B is functioning normally, the output from the comparison device 7B should be almost equivalent to the output from the circuit 20A. Therefore, in this example, by monitoring the output from the comparison device 16B, it is possible to detect early when the output from the circuit 20A and the output from the circuit 20B are greatly different. As a result, it is possible to detect a failure of the detection system that is normally difficult to detect, for example, midpoint fixation.
[0026]
In the present invention, the output signal from the vibrator includes a true detection signal corresponding to the angular velocity and a drive signal capacitive coupling component generated in the vibrator based on the drive vibration. A capacitively coupled component output circuit for detecting the component is provided. Particularly preferably, a plurality of output signals are output from the vibrator, and the capacitive coupling component output circuit adds the plurality of output signals from the vibrator to cancel the detection signals included in the plurality of output signals, thereby An adding means for amplifying the coupled component is provided. This will be described with reference to FIG.
[0027]
The output signal may contain a drive signal capacitive coupling component. The frequency of this component is the same as the frequency of the drive signal. In the present embodiment, the phase of the detection signal output from the detection unit 2A is set to be opposite to the phase of the detection signal output from the detection unit 2B. On the other hand, the phase of the capacitive coupling component included in the output signal from the detection unit 2A is in phase with the phase of the capacitive coupling component included in the output signal from the detection unit 2B.
[0028]
Therefore, when the subtractor 11 subtracts the output signal from the detection unit 2A and the output signal from the detection unit 2B, the genuine detection signal included in each output signal is amplified. Further, the capacitive coupling component included in each output signal is canceled out. The signal after this subtraction is processed in the detection signal output circuit 20B as described above to obtain a detection signal corresponding to the angular velocity.
[0029]
On the other hand, the capacitive coupling component output circuit 20C performs the following processing. That is, first, the adder 21 adds the output signal from the detector 2A and the output signal from 2B. Then, the genuine detection signal included in each output signal is canceled and erased. At the same time, the capacitive coupling component included in each output signal is amplified because it is in phase. As described above, the output signal after the addition is amplified by the AC amplifier 12C and detected by the derivative signal (the signal after the phase) by the detector 13C to cut the leakage signal component. Next, the detected signal is passed through the low-pass filter 14C and the voltage comparator 7C. The voltage comparator 7C diagnoses the capacitive coupling component, and if an abnormality is found, an alarm is output from the terminal 16D.
[0030]
By detecting an abnormality in the driving vibration capacitive coupling component, it is possible to detect disconnection of the connection portion between the vibrator and the electric circuit that cannot be detected by the diagnosis of the oscillation state and a change in resistance value. Further, the failure of the first stage preamplifiers 10A and 10B can be detected.
[0031]
In the reference example , the output signal includes a leakage signal component generated in the vibrator based on the drive vibration, and the diagnostic circuit includes a leakage signal component output circuit that detects the leakage signal component. As described above, the leakage signal component has the same frequency as the driving vibration and has the same phase. Even if the oscillation circuit is normal, if an abnormality occurs in the vibrator and the vibration state changes, the leakage signal component is changed abnormally or greatly. Therefore, by monitoring the leakage signal component, it is possible to detect an abnormality of the vibrator that cannot be detected only by monitoring the drive signal.
[0032]
FIG. 3 is a block diagram schematically showing an apparatus according to this reference example . In the leakage signal output circuit 20D, each output signal is first subtracted by the subtractor 11, thereby cutting the capacitive coupling component and amplifying the leakage signal component and a genuine detection signal corresponding to the angular velocity. Next, the output from the subtractor 11 is amplified by the AC amplifier 12D and detected by the detector 13D. At this time, a phase shift signal shifted by 180 ° from the drive signal is used for the detector 13D. In other words, the above-described derivative signal is supplied to the phase shifter 9 and phase-shifted by 90 °, for example, and then this phase-shifted signal is supplied again to the phase shifter 19 and phase-shifted 90 ° again. When detection is performed using the phase shift signal thus obtained, a true detection signal corresponding to the angular velocity is detected and cut. At the same time, the leakage signal component is not detected and passes through the detector 13D.
[0033]
The detection output after this detection is passed through the low-pass filter 14D and then supplied to the voltage comparator 17D for diagnosis. If an abnormality is found in the leakage signal component, an alarm is output from the terminal 16E.
[0034]
In the reference example , the detection terminal for connecting the output from the detection signal output circuit to the external electric system and the negative terminal or the positive terminal of the power source of the angular velocity measuring device are connected via a resistor. This will be described with reference to FIG.
[0035]
In FIG. 4, the angular velocity measuring device 21 is connected to the external electrical system 26 by a wire 25. 22A is a positive terminal of the power supply, 22C is a negative terminal of the power supply, and 22B is an output terminal from the detection signal output circuit. In this example, a resistor 24 is interposed between the detection terminal 22B and the positive terminal 22A. Each terminal is connected to a terminal 23 on the external electrical system side. As a result, the magnitude of the output from the detection terminal 22B is reduced by the resistance value of the resistor 24 as compared with the magnitude of the power supply voltage. For example, if the rated voltage of the power supply is 5 volts, the output from the detection terminal can be set to 4.5 volts or less (set to a maximum of 4.5 volts), for example. Here, when a short circuit occurs in the wire harness portion or an open failure occurs, the output from the detection terminal 22B exceeds 4.5 volts, for example, near 5 volts, so that an abnormality can be detected.
[Brief description of the drawings]
FIG. 1 is a block diagram schematically showing an apparatus according to a reference example , which includes a detection signal output circuit 20B and a comparison signal output circuit 20A.
FIG. 2 is a block diagram schematically showing an apparatus according to the present invention, which includes a detection signal output circuit 20B and a capacitive coupling component output circuit 20C.
FIG. 3 is a block diagram schematically showing an apparatus according to a reference example , and includes a detection signal output circuit 20B and a leakage vibration component output circuit 20D.
4 is a schematic diagram showing a connection portion between the angular velocity measuring device 21 and an external electric system 26. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Drive part 2A, 2B Vibrator detection part 3 Drive means 4A, 4B Detection means 7A, 7B, 7C, 7D Voltage comparator 8 Self-excited oscillation circuit 9, 19 Phase shifter 10A, 10B Preamplifier 11 Subtractor 12A, 12B, 12C, 12D AC amplifier 13A, 13B, 13C, 13D Detector 14A, 14B, 14C, 14D Low-pass filter 15A, 15B Limiter 16A Self-excited oscillation state diagnostic terminal 16B Comparison terminal 16C Detection signal 16C Detection signal Output terminal 16D output terminal of driving vibration capacitive coupling component 16E output terminal of leakage signal 20A comparison signal output circuit 20B detection signal output circuit 20C capacitive coupling component output circuit 20D leakage vibration component output circuit 21 angular velocity measuring device 22A, 22C power supply terminal 22B Detection terminal 26 External electrical system

Claims (2)

An angular velocity measuring device for measuring the angular velocity of rotation applied to a vibrator,
A vibrator, a drive circuit for exciting drive vibration in the vibrator, a detection signal output circuit for processing a signal output from the vibrator and obtaining a detection signal corresponding to the angular velocity, and the detection signal output circuit The output signal includes a drive signal capacitive coupling component having the same frequency as the drive vibration generated in the vibrator based on the detection signal and the drive vibration. A plurality of the output signals are output from the vibrator, and the diagnostic circuit includes a capacitive coupling component output circuit that processes the output signals and outputs the drive signal capacitive coupling component after the signal processing, The capacitively coupled component output circuit adds the plurality of output signals from the vibrator to cancel out the detection signals in opposite phases included in the plurality of output signals, thereby And an addition means for amplifying a signal capacitive coupling component, the detection signal output by detecting and detected by the phase shift signal based on a drive signal for the drive signal capacitively coupled components after addition obtaining the detection signal An angular velocity measuring device for diagnosing a circuit.   A detection terminal for connecting an output from the detection signal output circuit to an external electric system, and a negative electrode terminal or a positive electrode terminal of the power source of the angular velocity measuring device are connected via a resistor, The angular velocity measuring device according to claim 1.

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