JPH04152210A - Angular velocity sensor correcting method - Google Patents

Abstract

PURPOSE:To obtain the real angular velocity rid of fluctuation elements by removing characteristic fluctuation generated in association with the temperature fluctuation and the lapse of time, from the output of an angular velocity sensor. CONSTITUTION:An arithmetic part 7 integrates the digital value D1. corresponding to a signal omega generated at a sensor part body 1 every specified sampling period and outputs an angle signal phi. Data Ks (T) and B(T) corresponding to the temperature T measured by a temperature sensor 8 are read from look-up tables 10, 11. The arithmetic part 7 performs correction on the basis of the data D1, Ks(T), B(T) and the time elapsed data from the measurement starting time so as to compute the real angle PHI. The characteristic fluctuation generated in association with the temperature fluctuation and the lapse of time is thus removed from the output of an angular velocity sensor so as to obtain the real angular velocity or the angle rid of these fluctuation elements.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an angular velocity sensor that measures the motion of a moving body as an angular velocity or an angle obtained by integrating the angular velocity, and particularly relates to an angular velocity sensor that measures the motion of a moving body as an angular velocity or an angle obtained by integrating the angular velocity. The present invention relates to a method of correcting an angular velocity sensor for correcting inherent fluctuation errors associated with angular velocity sensors.

[Prior Art] Conventionally, in an angular velocity sensor, a sensor main body outputs an angular velocity signal of a moving body, and the angular velocity signal is further integrated by an integrator to generate an azimuth signal of the moving body. For this reason, it can be applied to the measurement and control of the angular motion of a moving body, and is known to be applied to, for example, the measurement of sway, the measurement of maneuvering stability, or the control of aircraft, automobiles, and ships.

It is also applied to measurement devices for measuring the direction of excavation of excavated holes in subway construction and tunnel construction, and hole bending measurement devices for measuring the direction of excavation of relatively small-diameter holes such as water and sewage pipes and gas pipes. There is.

The output of the angular velocity sensor has a temperature-dependent fluctuation component and a time-dependent fluctuation component. The fluctuation component becomes an error, and the measurement output of the angular velocity sensor cannot be used as is as the angular velocity or angle. For this reason, conventionally, before starting measurement, the output of the angular velocity sensor was sampled for a certain period of time with the angular velocity sensor stationary, and the data was averaged to determine the error of the angular velocity sensor. During measurement, it is assumed that the output signal of the angular velocity sensor includes this error, and the angular velocity sensor is corrected by subtracting the error and treating it as the true angular velocity.

[Problems to be Solved by the Invention] However, as in the conventional correction method, it is not possible to obtain highly accurate angular velocity or angle by simply correcting a fixed value obtained by averaging the output signal of the angular velocity sensor in a stationary state. The problem was that it could not be done.

An object of the present invention is to provide a correction method for correcting these fluctuation components to realize a highly accurate angular velocity sensor.

[Means for Solving the Problems] In order to achieve the above object, the present invention boils the following oak.

First, the present invention is directed to a correction method for an angular velocity sensor that obtains a true angular velocity or angle by removing an error temperature fluctuation component included in the output of the angular velocity sensor and a unique fluctuation component that fluctuates over time.

The first invention of the present application regarding this angular velocity sensor correction method includes: a first step of providing a temperature sensor within the angular velocity sensor, measuring representative scale factors and DC offsets at several points in advance, and creating a look-up table; The method is characterized by comprising a second step of measuring the temperature within the angular velocity sensor with the temperature sensor during actual measurement, and correcting the component of the temperature change of the DC offset and scale factor.

In addition, as a second invention of the present application, the angular velocity sensor is kept in a stationary state, and the output signal No. 1 of the angular velocity sensor and the data of the temperature sensor are sampled for a certain period of time every predetermined cycle, and each data is set to the temperature specified in the previous section. A first step of removing DC offset error components related to fluctuations; linear prediction is performed on the temperature fluctuation corrected data, and an error component that fluctuates in proportion to time is determined from a DC offset error component that has no temperature dependence; When measuring,
The present invention is characterized by comprising a second step of correcting the DC offset error component having no temperature dependence and the error component varying in proportion to time.

Further, the principle of the correction method of the present invention will be explained as follows.

The output signal ω generated in the sensor body of the angular velocity sensor is
As shown in the following equation (1), the temperature variation coefficient (referred to as a scale factor) K is added to the true angular velocity ω.

(T) (where T is the temperature value) and the DC offset component B (
T), a constant value DC offset component B that has no temperature dependence, and a component KL-t that has no temperature dependence but fluctuates in proportion to the passage of time t (however, K1. is a proportionality constant)
It is expressed as the sum of

ω−KS (T) ・Ω+B (T) +B+KL
-t...(1) Furthermore, the output ω when the angular velocity sensor is in a stationary state is
From the relationship Ω=0, ω=B (T) +B+KL -t...
It is expressed as (2).

Then, before starting actual measurement, the angular velocity sensor is placed in a stationary state and the output is sampled at every predetermined period, thereby producing a plurality of outputs ω1. ω2゜...ω7-1. ω.

was actually measured, and further, the following equation (3) based on the above equation (2) and (
4) predicts L and B as constants related to temperature-independent components using the least squares method calculation. However, B
(T) is determined by referring to a lookup table described later.

(↓【 Δ1.)−Δt n l−1 g= (” 'E (t)+) Kt '(" ”
X Δtl)n l+l
n I-+ (4) In the above equations (3) and (4), n is the number of samples of the output ω, and Δ1+ is the period of each sampling.

On the other hand, for the temperature-dependent component B (T), an angular velocity sensor kept stationary in a thermostatic chamber or the like is set at several representative temperatures, and the output ω at each temperature is actually measured.

Furthermore, for the temperature-dependent component KS (T), the output ω for each temperature is actually measured by operating an angular velocity sensor at a known angular velocity Ω in a thermostatic oven or the like.

These components B (T) and Kg ('r) are stored in advance in the storage means of the calculation section as data for each temperature. This is called a lookup table.

Then, the output value ω generated by the angular velocity sensor during actual measurement operation, the data B (T) and KS (T) for the temperature T of the angular velocity sensor measured simultaneously by the temperature sensor, and the elapsed time t from the start of measurement are as follows. By substituting into equation (5), the corrected angular velocity Ω is calculated.

Note that the component B and the constant KL are determined in advance before the start of the actual measurement, as described above.

Further, the output of the integrator within an appropriate time Δ can be determined as the corrected azimuth φ (=Ω·Δt) from the relationship of the following equation (6).

[Operation] According to the correction method of the present invention, temperature fluctuations and inherent fluctuations over time are removed from the output of the angular velocity sensor, so the true angular velocity or You can get the angle.

[Embodiment 1] Hereinafter, an embodiment of an angular velocity sensor and an integrator incorporating a correction circuit according to the correction method of the present invention will be described with reference to the drawings.

First, the configuration will be explained with reference to FIG. In the same figure, 1
is the main body of the sensor section of the angular velocity sensor, which outputs an analog signal ω representing the angular velocity of the moving body.

However, the signal ω is a signal before correction that includes the true angular velocity Ω, a temperature fluctuation component, and a component that fluctuates over time.

2 is an integrator that integrates the difference between the signal ω and the D/A converter 6;

3 is a triangular wave generation circuit which outputs a triangular wave signal S1 having a preset frequency and constant amplitude.

4 is a comparator, to which a triangular wave signal S1 is applied to a non-inverting input contact, and a signal obtained by integrating the difference between the signal ω and the D/A converter 6 is applied to an inverting input contact. When the voltage of each signal has a relationship of 83≧81, the logical value is “H”
, S3<Sl, a rectangular signal S4 having a logic value "L" is output.

5 is a counter, which counts the time when the rectangular signal S4 reaches H'' level within a predetermined sampling period Δ using a clock CK, and outputs it as a count value D1.The data D1 of the counter is output to the calculation section and The data D1 is output to the D/A converter 6, which generates an analog voltage corresponding to the data D1, and feeds this back to the integrator 2.

This kind of feedback loop is formed, so
The input angular velocity ω and the output signal of the D/A converter 6 always match.

With the above configuration, the input angular velocity ω can be detected as data D1 (digital value).

8 is a temperature sensor provided inside the sensor section 1;
A temperature signal S5 indicating the temperature T of the sensor body 1 is supplied to the A/D converter 9.

A/D converter 9 converts temperature signal S5 into AD. The temperature data AD and the signal from the angular velocity sensor are processed to create lookup tables 10 and 11 made of nonvolatile memory.

The first lookup table 10 stores in advance correction data KS ("r) for correcting the temperature dependence of the scale factor of the output signal ω of the sensor section 1, and the second lookup table 11 stores correction data KS ("r) for correcting the temperature dependence of the scale factor of the output signal ω of the sensor section In order to correct the temperature dependence of the DC component of the output signal ω of section 1, correction data B (
T) is stored in advance.

The calculation unit 7 receives input data DI.

By performing predetermined correction calculation processing on Ks (T) and B (T), data of true angular velocity Ω and angle Φ are output.

Next, the contents of lookup table 10.11 will be explained. These data are determined and stored by conducting tests in advance at a factory or the like before shipping the angular velocity sensor.

First, in this embodiment, as shown in equations (1) and (2) above, the output ω of the sensor unit 1 is calculated by multiplying the true angular velocity Ω by the temperature variation coefficient (scale factor) K, (T). and the DC offset component B (
T), a constant value DC offset component B that has no temperature dependence, and a component Kt-t that has no temperature dependence but fluctuates in proportion to the passage of time t.

In the test before shipping, the angular velocity sensor is kept stationary and the temperature is 10°C in the range of -10°C to +50°C.
The temperature is changed every time, and the output B (T) of the angular velocity sensor at each set temperature is set.

Next, place the angular velocity sensor in a thermostatic chamber and set it to operate at a predetermined angular velocity Ω, for example, minus 1.
The temperature is changed in steps of 10°C from 0°C to +50°C, and the output of the angular velocity sensor at each set temperature is expressed as Ks.
('r). The respective data Ks (T) and B (T) obtained by this calculation are stored in a lookup table 10.11.

Then, output data AD indicating the temperature T of the A/D converter 9
5 (T) and B (T) will be output as data for each temperature.

After the lookup table 10.degree. 11 is formed in this manner, it is shipped.

Next, the operation when performing actual measurement will be explained.

First, the error is estimated during a predetermined period of time before the start of the measurement operation (referred to as to). That is, during this time, the constants KL and B of the sensor body 1 are determined in advance with high accuracy by the calculation unit 7 calculating the above equations (3) and (4).

That is, in estimating this error, the angular velocity sensor is placed in a stationary state (that is, Ω-0), and the data D1 corresponding to the signal ω output from the sensor section 1 is measured every predetermined sampling period Δ. Based on a plurality of n data obtained by this measurement [corresponding to ω1 in the above equations (3) and (4), the calculation unit 7 calculates the above equations (3) and (4) to obtain a constant KL and B are calculated, and these constants are applied in correction processing during actual measurement.

Next, when this adjustment process is completed and actual measurement is started (time t), the calculation unit integrates the digital value D1 corresponding to the signal ω generated in the sensor body 1 every predetermined sampling period Δ. It processes and outputs an angle signal φ. Furthermore,
Data KS corresponding to temperature T measured by temperature sensor 8
(T) and B(T) are each lookup table 1.0.
Read from 11. The calculation unit 7 calculates these data D1, 5(T), B(T), and the measurement start time t. A correction process is performed by substituting the data of the time elapsed from t into the above equation (6), and the true angle Φ is calculated.

Then, when the measurement is continued, the measurement data D at that point
1, (T) and B (T) and the measurement start time t. The correction is performed by substituting the elapsed time t from t to the above equation (6).

In this way, according to this embodiment, temperature fluctuations and inherent fluctuations over time are removed from the output of the angular velocity sensor, so it is possible to obtain the true angular velocity or angle excluding these fluctuation components. I can do it. In addition, by performing the adjustment process immediately before starting the actual measurement, the fluctuation tendency of the constants KL and B due to the inherent fluctuation over time can be determined, and these constants KL and B can be calculated immediately after the adjustment process. Since this method is applied, the temporal continuity between the adjustment process and the actual measurement is maintained, making it possible to perform highly accurate correction.

Next, a specific example of a device using a vibrating gyroscope as an angular velocity sensor having such a correction function is shown in Figures 2 to 4.
This will be explained with figures.

This relates to a hole curvature measuring device that three-dimensionally measures the shape of the curvature of relatively small-diameter holes in water pipes, gas pipes, electrical pipes, and the like.

First, the external structure of the device will be explained based on FIG. In FIG. 2, reference numeral 12 denotes a water pressure vessel (shown partially cut away for convenience of explanation) consisting of a completely sealed cylindrical casing. , a thick cylindrical bearing mounting base 13 is integrally fixed with screws (not shown) or the like along the direction of the virtual center line zz'.

Two bearings 15 are installed in the hollow part 14 at the center of the bearing mounting base 13.
．． 16 are fitted apart from each other, and a rotating shaft 17 is rotatably supported by these bearings 15 and 16, and one end of the rotating shaft 17 is a gyro mount]8, and the other end is an accelerometer mount 19. It is fixed by press-fitting or screwing.

The sensor unit 1 of the vibration gyro is fixed to the gyro mounting base 18 with the input axis direction perpendicular to the virtual center line zz' (the direction of the virtual line Y-Y' in the figure), and the accelerometer The accelerometer 20 is mounted on the mounting base 19 at the virtual center line z-z.
' direction is fixed as the input axis direction.

Also, a gyro mounting base 18, a vibration gyro sensor section 1,
By shifting the entire center of gravity of the accelerometer 20 and the accelerometer mount 19 downward from the virtual center line 2-Zo of the rotating shaft 17, the sensor unit 1 and the accelerometer 2 of the vibrating gyro are
0 etc. constitute a pendulum with the rotating shaft 17 as the supporting axis.

Incidentally, since the friction between the bearings 15 and 16 and the air resistance of the pendulum are set to be extremely small, the damping rate of the mechanical vibration of the pendulum structure itself is small, but the vibration of the pendulum structure is suppressed by the magnetic damper shown in FIG. It is designed to attenuate the

That is, in FIG. 3, an annular permanent magnet 22 is fixed in an annular hole 21 provided in a bearing mounting base 13, and the permanent magnets 22 have, for example, adjacent ones along the circumference having different polarities. It is made up of multiple magnetic pieces with a

In addition, a return path forming part 2 made of a magnetic material such as pure iron
3 is inserted and fixed in the annular hole 21 of the bearing mounting base 13 in the same way as the permanent magnet 22, and a gap G is provided between the permanent magnet 22 and the return path forming part 23.

A cup-shaped damper 24 made of a conductor such as copper or aluminum is placed between the accelerometer mount 19 and the gap G, and the closed end 25 of the damper 24 is fixed to the accelerometer mount 19 with screws 26. At the same time, the cylindrical portion 27 on the opening side is inserted into the gap G.

In the magnetic damper having such a structure, when the cup-shaped damper 24 rotates around the virtual central axis zz', the cylindrical shape of the damper 24 is An overcurrent is generated in the portion 27, and a reaction force is generated that attempts to prevent the rotational movement of the cylindrical portion 27. Therefore, the motion of the damper 24 is attenuated.

Therefore, even if the water pressure container 12 rotates around the imaginary center line 22', due to the pendulum action and the action of the magnetic damper, the sensor unit 1 of the vibrating gyroscope will always have its input axis aligned with the imaginary line Y-Y'. The input axis of the accelerometer 20 is oriented in the direction of the virtual center line zz'.

Furthermore, a processing circuit for processing the output signals of the sensor section 1 of the vibrating gyroscope and the accelerometer 20 is built into the water pressure container 12 . That is, the sensor section 1 of the vibrating gyroscope is connected to a processing circuit 28 having a correction function having a circuit configuration shown in FIG.
The accelerometer 20 is connected to a low-pass filter 29 that removes high-frequency components of the tilt angle signal, and an A/D converter 30 that converts the output signal of the low-pass filter 29 to digital data. It includes an arithmetic and communication circuit 31 that receives digital data output from the /D converters 30, respectively.

A cable 32 is connected to one end of the water pressure vessel 12 along the zz' center line. Further, a transmission line wired along the cable 32 is connected to the output terminal of the calculation and communication circuit 31, and the above-mentioned digital data is connected to the terminal end of the transmission line via the calculation and communication circuit 31 and the transmission line. The data is transmitted to the main body of the measuring instrument.

Next, a measurement method using the hole bending measuring device having such a configuration will be explained.

As shown in FIG. 4, first, the water pressure container 12 is pushed in from the entrance of the hole to be measured toward the deep part.

At the time of this pushing, force is applied to the cable 32 for carrying in from the longitudinal direction, but since the cable 32 has the rigidity to resist this force, the water pressure vessel 12 is moved along the hole to be measured.
can be inserted deep into the body. Further, since the cable 32 has some flexibility, it is inserted while being bent according to the bend of the hole.

Then, the water pressure container 12 is inserted to an appropriate point such as the deepest recirculation part of the hole to be measured, and the water pressure container 12 is kept in a stationary state to perform the above-mentioned adjustment process. That is, adjustment processing is performed to obtain constants KL and B necessary for correcting the output of the sensor section 1 of the vibration gyroscope.

Subsequently, each time the cable 32 is pulled out by a predetermined length L, the azimuth and inclination angle at each point are measured, the three-dimensional position of each point is calculated, and the water pressure vessel 12 is positioned in the hole to be measured. Repeat until you reach the entrance.

Furthermore, by displaying the obtained results on a CRT display, an X-Y plotter, etc. provided in the main body of the measuring device, the three-dimensional position of the entire hole is displayed as shown in FIG.

In this way, according to this specific example, even small-diameter holes in water pipes, gas pipes, etc. that cannot be measured by directly entering the hole can be measured with simple operations. .

[Effects of the Invention] As explained above, according to the present invention, the output of the vibrating gyroscope is assumed to include a temperature fluctuation component and a component that fluctuates over time in addition to a component indicating the true angular velocity. Since correction processing is performed to remove these fluctuation components from the actual output through predetermined arithmetic processing, the true angular velocity or angle can be measured with high accuracy.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a circuit according to an embodiment of the present invention, FIG. 2 is a perspective view showing the structure of a hole bending measuring device to which a vibrating gyroscope incorporating a correction circuit according to the present invention is applied, and FIG. FIG. 4 is an explanatory diagram showing a measuring method of the hole bending measuring device, and FIG. 5 is an explanatory diagram showing an example of display of measurement results of the hole bending measuring device. Explanation of symbols; 1: Sensor section of angular velocity sensor Main body 2: Integrator 3, triangular wave generation circuit 4: Comparator 5: Counter 5: D/A converter 7/calculation section 8: Temperature sensor 9: A/D converter 10.11. Niltsukuup Tape 28: Processing circuit patent applicant Tokime・νri Co., Ltd.

Claims (2)

[Claims] (1) In an angular velocity sensor correction method for obtaining a true angular velocity or angle by removing an error temperature fluctuation component included in the output of the angular velocity sensor and a unique fluctuation component that fluctuates over time, the angular velocity sensor includes: We installed a temperature sensor and measured several typical scale factors and DC offsets in advance.
A first step of creating a lookup table; and a second step of measuring the temperature inside the angular velocity sensor with the temperature sensor during actual measurement and correcting the component of the temperature change of the DC offset and scale factor. A method for correcting an angular velocity sensor, characterized in that: (2) In an angular velocity sensor correction method for determining the true angular velocity or angle by removing an error temperature fluctuation component included in the output of the angular velocity sensor and a unique fluctuation component that fluctuates over time, the angular velocity sensor is kept stationary. a first step of sampling the output signal of the angular velocity sensor and the data of the temperature sensor for a certain period of time every predetermined cycle, and removing the DC offset error component related to the temperature fluctuation from each data; Linear prediction is performed on the temperature fluctuation corrected data,
An error component that fluctuates in proportion to time is determined from the DC offset error component that does not have temperature dependence, and during measurement, corrects the DC offset error component that does not have temperature dependence and the error component that fluctuates in proportion to time. A method for correcting an angular velocity sensor, comprising: a second step;