JPH10318757A - External force measuring equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an external force measuring equipment in which an external force is detected by an external force detection means and a value obtained by removing noise from a detection value is delivered to an integrating means. SOLUTION: At the post-stage of an angular sensor 1, a subtraction value VEn outputted from a substraction circuit 12 through an A/D conversion circuit 2 is passed through an averaging circuit 13 to produce an averaged value VFn, a decision is made at a decision circuit 14 whether the averaged value VFn comes within a first reference range Vt1 and a circuit 15 outputs a value VHn to be integrating a zero value or the subtraction value VEn selectively to an integrating circuit 16. When the averaged value VFn comes within a second reference range Vt2, a detection signal value Vn outputted from the angular sensor 1 is averaged to produce an averaged value VKn' which is then updated as an offset correction value V02 for the substraction circuit 12. According to the arrangement, random noise component and drift component of the detection signal value Vn can be reduced in the value VHn to be integrated outputted from the circuit 15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention removes components such as random noise and drift contained in a detection signal output from an external force detecting means such as an acceleration sensor and an angular velocity sensor, and outputs the signal after integration. The present invention relates to an external force measuring device.

[0002]

2. Description of the Related Art In general, in the case of a device for detecting a rotation angle, an external force measuring device according to the prior art detects and integrates an angular velocity signal in order to detect a rotation angle of a moving body to be measured. I am trying to do it.

However, when a displacement angle is obtained by integrating a signal corresponding to an angular velocity, when integrating a detection signal detected by an angular velocity sensor such as a gyro sensor,
The zero detection value of the sensor, which is a reference value for integration, drifts due to a change in temperature or the like, and this drift component accumulates as an error in the integration value indicating the displacement angle. Also,
Since this error increases with the passage of time, it is a major problem when detecting the displacement angle.

In order to eliminate this error, Japanese Patent Publication No. 4-76611 (JP-A-63-780) discloses one prior art.
No. 19) There is known an integral angle detection method as disclosed in the official gazette.

In this prior art, when a detection signal output from a sensor is within a reference range from a reference value of integration, integration is stopped, and the detection signal is within a reference range from a predetermined time before the detection signal exceeds this range. Until a certain time after entering, the dead band processing of performing the integration of the detection signal is performed, and when random noise or drift is within this reference range, this noise component can be removed,
A stable displacement angle signal can be obtained.

As a countermeasure against a case where the detected value zero, which is a reference value for integration, greatly drifts due to temperature fluctuation, etc.,
2. Description of the Related Art An offset drift correction device as disclosed in Japanese Patent Application Laid-Open No. 7-324941 (hereinafter referred to as another conventional technology) is known.

The offset drift correction device according to the prior art includes an angular velocity sensor for detecting an angular velocity, turning determination means for determining whether or not the moving body is performing a turning operation based on a detection signal output from the angular velocity sensor; And an adaptive filter for estimating and correcting an offset correction value of the angular velocity sensor using the average angular velocity obtained by smoothing the corrected angular velocity when the turning determination means determines that the moving body is not performing a turning operation.

In the offset drift correction apparatus according to the prior art, the difference between the output from the angular velocity sensor and the output from the adaptive filter estimated at that time becomes an error amount of the estimated value, and this value is averaged. Only when it is determined that the vehicle is not turning by the turning determination means, the offset correction value is updated using the adaptive filter. As a result, after a sufficient time has elapsed, the offset correction value of the angular velocity sensor converges to the output from the adaptive filter, and the corrected angular velocity obtained by subtracting the estimated offset correction value from the angular velocity sensor is processed as an accurate angular velocity. Drift can be prevented and the drift component can be canceled.

[0009]

In the above-described integral angle detection method according to the prior art, in order to remove drift and random noise components and obtain a stable integrated signal, the reference range is determined by the detection signal. Needs to be set to a sufficiently large value for the random noise. As described above, when the reference range is set to be large, when the rotation speed is low, the angular speed becomes smaller than the reference range. The displacement angle at the time cannot be measured.

On the other hand, in this prior art, when the reference range is set small so that the angle can be measured even at low speed,
There is a problem in that integration is performed even for random noise exceeding the reference range, and an accurate displacement angle cannot be measured.

Another conventional apparatus for offset drift correction is to sequentially change an offset correction value. When an estimated value of an offset is obtained from an adaptive filter, a time delay occurs, and an actual true offset value is corrected. A shift occurs between the correction value and the estimated offset correction value. For this reason, there is a possibility that the deviation affects the integral value, and an error occurs in which the angle value changes despite being stationary.

The present invention has been made in view of the above-mentioned problems of the prior art, and the present invention provides an external force measuring apparatus capable of simultaneously removing a drift component, a random noise component, and the like in a detection signal by a simple process. It is intended to be.

[0013]

In order to solve the above-mentioned problems, an external force measuring device according to the first aspect of the present invention, as shown in FIG. 1, detects an external force applied to an object to be measured as a detection signal. Means 101, a subtraction means 102 for subtracting the offset correction value from the detection value of the detection signal output from the external force detection means 101, and a smoothing means for outputting the subtracted value output from the subtraction means 102 as a smoothed average value Means 103, determining means 104 for determining whether or not an external force is acting on the external force detecting means 101 using a smoothed average value, and zero if the determining means 104 determines that no external force is acting. Means for outputting a value as an integrand, and when it is determined that an external force is acting, an integrand output means for outputting a subtraction value output from said subtraction means 102 as an integrand. 05, 該被 integrated value output means 10
And an integration means 106 for integrating the integrand output from the control unit 5 and outputting the integration result as a measured value.

With this configuration, the subtraction means 102 subtracts the offset correction value from the detection value output from the external force detection means 101, and the smoothing means 103 outputs the subtracted value as a smoothed average value. . This makes it possible to smooth the random noise and reduce the peak value of the noise.

[0015] In the determination means 104, the smoothing means 10
Whether the average value output from 3 is within the reference range,
It is determined whether or not an external force is truly applied to the external force detecting means 101. In the integrand output means 105, the determination means 1
When it is determined in step 04 that the noise is truly applied with no external force, the zero value is output as the integrand value, and when it is determined that the external force is truly applied, the subtraction value output from the subtraction means 102 is used as the integrand value Output. Thereby, random noise in the integrand output from the integrand output means 105 can be reduced, and errors in the measured values integrated by the integration means 106 can be reduced.

Moreover, the smoothing means 103 smoothes the subtraction value, so that the peak value of the random noise included in the subtraction value can be reduced. Therefore, the setting of the reference range in the integrand value output means 105 can be reduced. Thus, the range in which the external force can be determined to be truly applied to the external force detecting means 101 can be expanded, and even when a small external force is applied, this external force can be detected.

The external force measuring device according to the second aspect of the present invention, as shown in FIG. 2, includes an external force detecting means 201 for detecting an external force applied to an object to be measured as a detection signal, and an output from the external force detecting means 201. Subtraction means 202 for subtracting the offset correction value from the detection value of the detection signal;
A first smoothing means 203 for outputting a subtracted value output from 2 as a smoothed first average value, and whether or not an external force is acting on the external force detecting means 201 is determined by using the first average value. The first determining means 204 determines whether or not an external force is applied. When the first determining means 204 determines that no external force is applied, a zero value is output as an integrand. Integral value output means 205 for outputting a subtraction value output from subtraction means 202 as an integrand value, and integrand value output from integrand value output means 205 for integration, and outputting the integration result as a measurement value An integrating means 206, a second determining means 207 for determining whether or not to update the offset correction value at the time of subtraction by the subtracting means 202, using the first average value;
When the determination means 207 determines that the first average value for updating the offset correction value is within the second reference range, the second average value obtained by smoothing the detection value output from the external force detection means 201 And a second smoothing means 208 which outputs the second
And an offset correction value updating means 209 for updating the average value of the subtraction means 202 as an offset correction value of the subtracting means 202.

According to this structure, the first aspect of the present invention is provided.
Similarly to the invention of the first aspect, the first smoothing means 203 smoothes the subtraction value, so that the peak value of the random noise included in the subtraction value can be reduced, and the criterion of the first determination means 204 can be lowered, and the external force The range in which it can be determined that an external force is truly applied to the detecting means 201 can be expanded, and an integrand close to the actual external force can be obtained.

In addition, the second determining means 207 determines whether the first
It is determined whether or not to update the offset correction value using the average value of the above. If it is determined that the offset correction value is to be updated, the second smoothing means 208 outputs the detection value output from the external force detection means 201 to the second value. And the offset correction value updating means 209 calculates the average value by the subtraction means 20.
2 is updated as the offset correction value. Thus, the drift component in the detected value can be reduced by always subtracting this offset correction value from the detected value by the subtracting means 202, and the integrand value closer to the actual angular velocity can be output from the integrand value output means 205. It can be output to the integration means 206.

Further, according to the third aspect of the present invention, the external force detecting means 30 detects an external force applied to the object to be measured as a detection signal.
1 and a subtraction means 302 for subtracting an offset correction value from a detection value of a detection signal output from the external force detection means 301.
And a first smoothing means 303 for outputting a subtracted value output from the subtracting means 302 as a smoothed first average value.
And a first average value output from the first smoothing means 303 is determined to be within a predetermined first reference range in order to determine whether an external force is acting on the external force detecting means 301. A first determining means 304 for determining whether or not there is a signal, and outputting a zero value as an integrand value when the first determining means 304 determines that the first average value is within a first reference range. An integrand output means 305 for outputting the subtraction value output from the subtraction means 302 as an integrand value when it is determined that the first average value is outside the first reference range;
An integrator 306 for integrating the integrand output from the integrator output 305 and outputting the integration result as a measured value;
And whether the subtraction value output from the subtraction means 302 is within a predetermined second reference range in order to determine whether or not to update the offset correction value when subtraction is performed by the subtraction means 302. A second determining means 307 for determining whether or not the subtraction value is within a second reference range, the detection value output from the external force detecting means 301 is smoothed. A second smoothing means 308 for outputting as a converted second average value,
And an offset correction value updating means 309 for updating the second average value output from the smoothing means 308 as an offset correction value of the subtracting means.

According to this structure, the first aspect of the present invention is provided.
Similarly to the first invention, the first smoothing means 303 smoothes the subtraction value, thereby reducing the peak value of random noise included in the subtraction value, and setting the first reference range in the first determination means 304. And the external force detecting means 30
The range in which it can be determined that an external force is truly applied to 1 can be expanded, and an integrand close to the actual external force can be obtained.

Further, the second determination means 307 determines whether the subtraction value output from the subtraction means 202 is within a second reference range, and determines that the subtraction value is within the reference range. The second smoothing means 308 uses the detection value output from the external force detecting means 301 as a second average value, and the offset correction value updating means 309 updates this average value as the offset correction value of the subtraction means 302. . As a result, the offset correction value is always subtracted from the detected value by the subtraction means 302, so that a drift component (temperature drift, etc.) in the detection value detected by the external force detection means 301
Can be reduced, and an integrand closer to the actual angular velocity can be output from the integrand output means 305 to the integration means 306.

According to the fourth aspect of the present invention, as shown in FIGS. 2 and 3, the second reference range in the second determination means 207 (307) is larger than the range during normal processing when the apparatus is activated. I have set it.

With the above configuration, even if the operation of the external force detecting means 201 (301) becomes unstable at the time of starting the apparatus, a large drift at the time of starting can be corrected by increasing the second reference range. Subtraction means 202 (30
The subtraction value output from 2) can be output stably.

[0025]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. Here, FIGS. 4 to 26 show an embodiment according to the present invention.
An angular velocity measuring device will be described as an example of the external force measuring device.

First, a first embodiment will be described with reference to FIGS.

Reference numeral 1 denotes an angular velocity sensor according to the present embodiment. The angular velocity sensor 1 is provided on a moving object (not shown) to be measured, and the angular velocity sensor 1 detects a gyro using Coriolis force. Sensors and the like are used.

Reference numeral 2 denotes an analog-to-digital conversion circuit (hereinafter referred to as an A / D conversion circuit). The A / D conversion circuit 2 reads an analog detection signal read from the angular velocity sensor 1 at predetermined time intervals, and outputs an analog signal. Is converted into a digital signal, and a detection value Vin is output.

Reference numeral 3 denotes an arithmetic circuit provided at the next stage of the A / D conversion circuit 2. The arithmetic circuit 3 includes a subtraction circuit 4, which will be described later.
It is roughly composed of a smoothing circuit 5, a determination circuit 6, an integrand value output circuit 7, an integration circuit 8, and the like.

Here, the configuration of the arithmetic circuit 3 will be described.
The subtraction value VAn is obtained by subtracting a preset offset correction value V01 from the th detection signal value Vn, and is calculated by the following equation (1).

[0031]

## EQU1 ## Van = Vn-V01

The smoothing circuit 5 calculates the moving average of the subtraction value Van output from the subtraction circuit 4 as in the following equation 2 to calculate the average value VBn. Thereby, the average value VBn
Reduces the random noise in the subtraction value Van by smoothing the high frequency component.

[0033]

(Equation 2) Where M1 is an integer of 2 or more

The determination circuit 6 stores a reference range Vs for determining whether or not an angular velocity is applied to the angular velocity sensor 1 in an attached storage circuit 6A. Then, the determination circuit 6 determines whether or not the moving average value VBn output from the smoothing circuit 5 is within the reference range Vs. When it is determined that the moving average value VBn is within the reference range Vs, the determination signal VC is converted to the integrand value. Output to the output circuit 7.

The integrand output circuit 7 receives the judgment signal VC output from the judgment circuit 6, and when the judgment signal VC is input, sets the zero value to the integrand VDn and sets the judgment signal VC to zero.
When there is no input, the subtraction value Van output from the subtraction circuit 4 is output as the integrand value VDn. in this way,
The integrand value output circuit 7 performs a switching operation of selecting a zero value and a subtraction value Van depending on the presence or absence of the determination signal VC, and outputting this signal as the integrand value VDn.

The integrating circuit 8 integrates the integrand value VDn output from the integrand value output circuit 7 and outputs the result as the displacement angle θ.
It outputs to the signal output circuit 9 as a measurement value VOn indicating n.

Further, reference numeral 9 denotes a signal output circuit provided at the next stage of the arithmetic circuit 3, and the signal output circuit 9 outputs the measured value VOn calculated by the arithmetic circuit 3 to a subsequent circuit (not shown). I do.

Next, based on the processing program of FIG.
The operation of the integrand output processing of the arithmetic circuit 3 will be described.

First, in step 1, the detection signal value Vn output from the angular velocity sensor 1 is read every predetermined time (for example, 20 mS) (see the waveform (a) in FIG. 6). A subtraction value Van obtained by subtracting a preset offset correction value V01 from the signal value Vn is represented by Vn-V
The calculation is performed as 01 (see the waveform (b) in FIG. 6).

In step 3, a moving average value VBn of the subtraction value Van is calculated based on the above equation (2) to reduce the random noise added to the subtraction value Van, thereby obtaining a waveform as shown in FIG. An average value VBn is obtained.

In step 4, it is determined whether or not the average value VBn is within the reference range Vs. If "YES" is determined, the detection signal value Vn is determined when the angular velocity is not applied to the angular velocity sensor 1. And the process proceeds to step S5. Then, in step 5, the subtraction value Van is set to a zero value (see the area a of the waveform (e) in FIG. 7).

On the other hand, if "NO" is determined in step 4, it is determined that the average value VBn exceeds the reference range Vs. Move on to In step 6, the subtraction value Van is output as it is (the region b of the waveform (e) in FIG. 7).
reference).

Further, in step 7, the subtraction value Van set in this way is replaced with the integrand value VDn, and in step 8
Then, the integrand value VDn is integrated to obtain a measurement value VOn (see waveform (f) in FIG. 7). Then, the process returns in step 9.

Next, based on the waveform diagrams of FIGS. 6 and 7, the specific operation of the angular velocity measuring device according to the present embodiment will be described.
This will be described in relation to the processing in FIG.

First, in FIG. 6, the upper waveform (a) is the detection signal value Vn input from the angular velocity sensor 1 to the arithmetic circuit 3 via the A / D conversion circuit 2, and the lower waveform (b) is Vn- V
01 and the subtraction value V output from the subtraction circuit 4
An is shown respectively. In the upper waveform (c) in FIG. 7, the smoothing circuit 5 calculates the moving average of the subtraction value Van as in the above equation (2).
, The waveform (d) indicates the judgment signal VC output from the judgment circuit 6, and the waveform (e) indicates the integrand value VDn output from the integrand output circuit 7, respectively. (F) is the measured value VOn output from the integration circuit 8
Is shown.

First, the detection signal value V of the waveform (a) in FIG.
n is a waveform on the upper right with the slope of the drift signal D due to temperature change, aging, and the like. In addition, random noise is superimposed on a portion where no angular velocity is applied.

By the process of step 2, the subtraction value Van is calculated, and the subtraction is performed by subtracting the offset correction value V01 as shown in the waveform (b). Next, in the process of step 3, the moving average of Expression 2 is calculated in order to reduce the noise component, and a waveform having a high frequency such as a waveform (c) is removed to reduce noise components.

In the processing of steps 4 to 7, when the average value VBn is within the reference range Vs, that is, in the regions a and a, the judgment signal VC shown in the waveform (2) is output from the judgment circuit 6 to the integrand output circuit. 7, the integrand output circuit 7 receives the judgment signal VC, sets the subtraction value Van to zero, and sets the subtraction value Van as the integrand value VDn.
(See region a of waveform (e)).

On the other hand, when the average value VBn is out of the reference range Vs, that is, when the average value VBn is in the region b, the judgment signal VC is not output. VAn is output as it is, and the subtracted value Van is output from the integrand value output circuit 7 to the integrator circuit 8 as the integrand value VDn (see the area b of the waveform (e)).

In the angular velocity measuring apparatus according to the present embodiment having such a configuration, the integrand value V
Dn can be set to a waveform from which the drift component and the random noise component in the detection signal value Vn have been removed, and the integrand value VDn
Is integrated by the processing in step 8, it is possible to detect an accurate displacement angle θn (see waveform (f) in FIG. 7).

Since the smoothing circuit 5 is provided between the subtracting circuit 4 and the judging circuit 6, the average value VBn output from the smoothing circuit 5 contains the random noise included in the detection signal value Vn or the subtraction value Van. Can be reduced.

As a result, in the judgment circuit 6, the smoothing circuit 5
Is compared with the reference range Vs,
Since it is determined whether or not the angular velocity is applied to the angular velocity sensor 1, it is determined whether or not the angular velocity is truly applied to the angular velocity sensor 1 by reducing the noise in the average value VBn to be determined. Can be performed accurately.

Further, since the judgment circuit 6 makes the judgment by comparing the average value VBn with the reference range Vs, the noise in the subtraction value Van by the smoothing circuit 5 is reduced by the noise in the reference range. Exceeding Vt can be reduced. The output of the integrand value VDn output from the integrand value output circuit 7 can be reduced as noise is output as the integrand value VDn.

Further, in order to prevent erroneous detection due to noise as in the prior art, it is not necessary to set a large reference range serving as a dead zone processing area, and even when the angular velocity applied to the angular velocity sensor 1 is small, the angular velocity is reduced. The corresponding angular displacement θn can be measured, and the detection sensitivity of the angular velocity can be increased.

In this embodiment, the reference range Vs is set large in order to correct the case where the random noise and the drift component are superimposed on the detection signal value Vn. In the case of the value Vn, the reference range Vs can be set small, and the detection range of the angular velocity can be widened.

Next, a second embodiment according to the present invention will be described with reference to FIGS.

The feature of this embodiment is that the offset correction value update setting process is performed in addition to the integrand value output process according to the first embodiment. It is determined whether or not the smoothed average value is within a second reference range, and when it is determined that the average value is within the second reference range, the detection value output from the external force detection means is smoothed. This is updated and set as an offset correction value when the average value is subtracted by the subtracting means.

In this embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

Numeral 11 denotes an arithmetic circuit provided at the next stage of the A / D conversion circuit 2. The arithmetic circuit 11 is used to perform an integrand output process almost in the same manner as the circuit described in the first embodiment. A subtraction circuit 12, a first smoothing circuit 13, a first determination circuit 14, an integrand output circuit 15, and an integration circuit 1 which will be described later.
6 and the like, the second determination circuit 17 and the second smoothing circuit 1 configured to perform the offset correction value update setting process.
8, an offset correction value updating circuit 19 and the like.

Here, the configuration of the arithmetic circuit 11 will be described. The subtraction circuit 12 subtracts a preset offset correction value V02 from an n-th detection signal value Vn detected from the angular velocity sensor 1, and calculates a subtraction value. VEn is obtained, and is calculated as in the following Expression 3.

[0061]

## EQU3 ## VEn = Vn-V02

The first smoothing circuit 13 includes the subtracting circuit 12
The first average value VFn is calculated by calculating the moving average of the subtraction value VEn output from the following equation (4). As a result, the average value VF is obtained by smoothing the high frequency component and subtracting the value VEn.
Reduce random noise inside.

[0063]

(Equation 4) Where M1 is an integer of 2 or more

The first determination circuit 14 stores a reference range Vt1 for determining whether or not an angular velocity is applied to the angular velocity sensor 1 in a storage circuit 14A attached thereto. Then, the determination circuit 14 determines whether or not the first average value VFn output from the first smoothing circuit 13 is within the reference range Vt1, and determines that the first average value VFn is within the reference range Vt1. Is output to the integrand output circuit 15.

The integrand output circuit 15 receives the first judgment signal VG output from the first judgment circuit 14 and, when the first judgment signal VG is input, changes the zero value to the integrand VHn. When there is no input of the first determination signal VG, the subtraction value VEn output from the subtraction circuit 12 is changed to the integrand value V
Output as Hn. Thus, the integrand output circuit 1
5 is a zero value and a subtraction value V depending on the presence or absence of the first determination signal VG.
En and a switching operation of outputting this signal as the integrand value VHn is performed.

The integrator 16 integrates the integrand VHn output from the integrator output 15 and outputs the result to the signal output circuit 9 as a measured value VOn indicating the displacement angle θn.

Further, the second determination circuit 17 stores a reference range Vt2 for determining whether or not to update the offset correction value V02 when the subtraction circuit 12 performs the subtraction in the storage circuit 17A attached thereto. Have been. Then, the second determination circuit 17 determines whether or not the first average value VFn output from the first smoothing circuit 13 is within the reference range Vt2, and determines that the first average value VFn is within the reference range Vt2. At times, the second determination signal VI is output to the second smoothing circuit 18.

The second smoothing circuit 18 includes a second judgment circuit 1
7 outputs the second determination signal VI, the A / D
A detection signal value Vn output from the angular velocity sensor 1 via the conversion circuit 2 is read in a correction reference value VJn ', and the correction reference value VJn' is converted into a second average value VJn '
Calculate Kn '. As a result, the average value VKn 'is used to extract drift noise in the detection signal value Vn by smoothing.

[0069]

(Equation 5) However, M2: an integer of 2 or more

The offset correction value updating circuit 19 receives the second average value VKn 'output from the second smoothing circuit 18, and updates the second average value VKn' as an offset correction value V02.

Next, the processing operation of this embodiment will be described based on the processing programs of FIGS. 9 and 10.

First, at step 11, a detection signal value Vn output from the angular velocity sensor 1 via the A / D conversion circuit 2 is read at predetermined time intervals (for example, 20 ms) (FIG. 11).
In step 12, a subtraction value Ven obtained by subtracting the offset correction value V02 from the read detection signal value Vn is calculated (see waveform (c) in FIG. 11).

In step 13, the moving average value VFn of the subtraction value VEn is calculated based on the above equation (4) to reduce the random noise added to the subtraction value VEn.
A first average value VFn as shown in waveform (d) of FIG. 2 is obtained.

In step 14, the first average value VFn
Is determined to be within the first reference range Vt1, and “YE
S ", the first average value VFn is within the first reference range Vt1, so that the detection signal value Vn is determined to be noise when the angular velocity sensor 1 is not applied with the angular velocity. Move to step 15. Then, in step 15, the subtraction value VEn is set to a zero value (a in the waveform (f) of FIG. 12).
Area).

On the other hand, if "NO" is determined in the step 14, it means that the first average value VFn has exceeded the first reference range Vt1, so that the angular velocity sensor 1 is truly applied with the angular velocity. And the process proceeds to step S16. In step 16, the subtraction value VEn is output as it is (FIG. 12).
Waveform (f), refer to the region b).

Further, in step 17, the subtraction value VEn set in this way is set to the integrand value VHn, and in step 18, the integrand value VHn is integrated to obtain the measurement value VOn (the waveform in FIG. 12). (G)). And step 19
Then, the offset correction value update setting process shown in FIG. 10 is performed, and the process returns in step 20.

Next, the offset correction value update setting processing will be described with reference to FIG.

First, at step 21, it is determined whether or not the first average value VFn calculated at step 13 is within the second reference range Vt2, and if it is determined to be "NO" (see the waveform (FIG. 13) In step d) (refer to region d), the process returns to step 25, and if "YES" is determined (see region c in waveform (h) in FIG. 13), step 22 is performed to update the offset correction value V02. The following processing is performed.

In step 22, the detected signal value Vn output from the angular velocity sensor 1 is read as a correction reference value VJn '. In step 23, the moving average of the correction reference value VJn' is calculated as shown in the following equation (5). Is obtained.

Further, at step 24, the second average value VKn 'is used as the offset correction value V02 to calculate the subtraction value of the second average value VKn'.
And the process returns in step 25.

Next, the specific operation of the angular velocity measuring device according to the present embodiment will be described with reference to the waveform diagrams shown in FIGS. 11 to 13 in relation to the processing of FIGS. 9 and 10.

First, the upper waveform (A) in FIG. 11 shows the detection signal value V output from the angular velocity sensor 1 to the arithmetic circuit 11.
n and waveform (b) show the offset correction value V02 output from the offset correction value updating circuit 19 to the subtraction circuit 12, and waveform (c) shows the subtraction value VEn output from the subtraction circuit 12.

The upper waveform (d) in FIG. 12 shows the first average value VFn output from the first smoothing circuit 13 obtained by moving-averaging the subtraction value VEn as shown in the above equation (4), and the waveform (e). Is a first determination signal VG output from the first determination circuit 14,
The waveform (f) shows the integrand value VHn output from the integrand value output circuit 15, and the lower waveform (g) shows the measured value VOn as the integration result output from the integration circuit 16.

Further, the upper waveform (h) in FIG. 13 is the first average value VFn obtained by moving-averaging the subtraction value VEn as shown in the above equation (4), and the waveform (r) is output from the second determination circuit 17. The second determination signal VI and the waveform (nu) are the second determination signal VI
Receiving the correction reference value V read into the second smoothing circuit 18
Jn ', the lower waveform (f) shows the correction reference value VJn'
And the second average value VKn 'output from the second smoothing circuit 18 after moving average is shown.

First, the detection signal value Vn of the waveform (a) in FIG. 11 is a waveform on the upper right with the slope of the drift signal D due to temperature change, aging, and the like. In addition, random noise is superimposed on a portion where no angular velocity is applied.

By the processing in step 12, the detection signal value V
The subtraction value VEn obtained by subtracting the offset correction value V02 of the waveform (b) from n is obtained. Next, the processing of step 13 calculates the moving average of Equation 4 in order to reduce the noise component, and removes the high frequency waveform such as the first average value VFn of the waveform (d) to remove the noise component. To reduce.

In the processing in steps 14 to 17, when the first average value VFn is within the first reference range Vt1, that is, in the regions a and a, the first determination signal V shown in the waveform (e)
G is output from the first determination circuit 14 to the integrand value output circuit 15. The integrand value output circuit 15 receives the first determination signal VG and sets the subtraction value VEn to a zero value. From the integrand value output circuit 15, this subtraction value VEn
Is output to the integration circuit 16 (see waveform (f)).

On the other hand, when the first average value VFn is outside the reference range Vt1, that is, in the region b, the first determination signal V
Since G is not output, the integrand output circuit 15 receives the first determination signal VG and outputs the subtraction value VEn as it is.
En is output to the integration circuit 16 as the integrand value VHn (see waveform (f)).

Further, based on the waveform diagram shown in FIG.
An offset correction value update setting process according to this embodiment will be described.

In step 21, when the first average value VFn calculated in step 13 is within the second reference range Vt2, that is, in the regions c and c, as shown in the waveform (i), the second The judgment signal VI is output to the second smoothing circuit 18. Then, the second smoothing circuit 18 receives the second determination signal VI and corrects the detection signal value Vn output from the angular velocity sensor 1 via the A / D conversion circuit 2 by a waveform (nu). The moving average of Equation 5 is calculated for the reference value VJn ',
The obtained second average value VKn ′ is output to the offset correction value updating circuit 19.

Here, the second average value VKn 'output from the second determination circuit 17 is obtained by removing a high frequency waveform.
This is a value from which noise components have been removed. Then, the second average value VKn 'becomes an offset correction value V02 (waveform (b) and waveform (l)).

In the angular velocity measuring apparatus according to the present embodiment having such a configuration, as described above, the random noise on which the detection signal value Vn is superimposed is removed by correcting the integrand output, and the offset correction value is updated. Thus, the drift component of the detection signal value Vn can be removed.

Thus, in the present embodiment, the first reference range Vt1 in the first determination circuit 14 can be made significantly smaller than the reference range Vs in the first embodiment.
As the integrand value VHn output from the integrand value output circuit 15, a value close to the actual angular velocity applied to the arithmetic circuit 11 can be obtained, and the displacement angle θn can be detected with high sensitivity.

Next, a third embodiment of the present invention will be described with reference to FIGS.

The feature of this embodiment is that an offset correction value update setting process is performed in addition to the integrand output process according to the first embodiment. The offset correction value update setting process determines whether the subtraction value is within the second reference range, and when it determines that the average value is within the second reference range, the external force detection means This is updated and set as an offset correction value when the average value obtained by smoothing the output detection value is subtracted by the subtraction means.

In this embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

Reference numeral 21 denotes an arithmetic circuit provided at the next stage of the A / D conversion circuit 2. The arithmetic circuit 21 is used to perform an integrand output process in substantially the same manner as the circuit described in the first embodiment. A subtraction circuit 22, a first smoothing circuit 23, a first determination circuit 24, an integrand value output circuit 25, and an integration circuit 2 which will be described later.
6, a second determination circuit 27 and a second smoothing circuit 2 configured to perform a new offset correction value update setting process.
8, an offset correction value updating circuit 29.

Here, the configuration of the arithmetic circuit 21 will be described. The subtraction circuit 22 subtracts a preset offset correction value V03 from an n-th detection signal value Vn detected from the angular velocity sensor 1, and calculates a subtraction value. VLn is obtained, and is calculated as in the following Expression 6.

[0099]

## EQU6 ## VLn = Vn-V03

The first smoothing circuit 23 includes the subtracting circuit 22
The first average value VMn is calculated by calculating the moving average of the subtraction value VLn output from the following equation (7). As a result, the first average value VMn smoothes a high frequency component to reduce random noise in the subtraction value VLn.

[0101]

(Equation 7) Where M1 is an integer of 2 or more

The first determination circuit 24 stores a reference range Vu1 for determining whether or not an angular velocity is applied to the angular velocity sensor 1 in an attached storage circuit 24A. The determination circuit 24 determines whether or not the first average value VMn output from the first smoothing circuit 23 is within the reference range Vu1, and determines that the first average value VMn is within the reference range Vu1. Is output to the integrand value output circuit 25.

The integrand value output circuit 25 receives the first judgment signal VN output from the first judgment circuit 24 and, when there is an input of the first judgment signal VN, changes the zero value to the integrand value VPn. When there is no input of the first judgment signal VN, the subtraction value VLn output from the subtraction circuit 22 is changed to the integrand value VN.
Output as Pn. Thus, the integrand output circuit 2
5 is a zero value and a subtraction value V depending on the presence or absence of the first determination signal VN.
Ln, and a switching operation of outputting this signal as the integrand value VPn is performed.

The integrator 26 integrates the integrand VPn output from the integrator output 25 and outputs the result to the signal output circuit 9 as a measured value VOn indicating the displacement angle θn.

Further, the second judgment circuit 27 stores a reference range Vu2 for judging whether or not to update the offset correction value V03 when the subtraction is performed by the subtraction circuit 22 in the attached storage circuit 27A. Have been. Then, the second determination circuit 27 determines whether or not the subtraction value VLn output from the subtraction circuit 22 is within the reference range Vu2. When it is determined that the subtraction value VLn is within the reference range Vu2, the second determination signal is output. VQ
To the second smoothing circuit 28.

The second smoothing circuit 28 is provided with a second judgment circuit 2
7 outputs the second determination signal VQ, the A / D
The detection signal value Vn output from the angular velocity sensor 1 via the conversion circuit 2 is read as a correction reference value VRn ', and this correction reference value VRn' is calculated based on the moving average equation (8). Is calculated. As a result, the average value VSn '
Extracts the offset drift in the detection signal value Vn by smoothing the high frequency component.

[0107]

(Equation 8) However, M2: an integer of 2 or more

The offset correction value updating circuit 29 receives the second average value VSn 'output from the second smoothing circuit 28, and updates the second average value VSn' as the offset correction value V03.

Next, the processing operation of this embodiment will be described based on the processing programs of FIG. 15 and FIG.

First, in step 31, the detection signal value Vn output from the angular velocity sensor 1 is read at predetermined time intervals (for example, 20 mS) (see the waveform (a) in FIG. 17). A subtraction value VLn obtained by subtracting the offset correction value V03 from the signal value Vn is calculated (see waveform (c) in FIG. 17).

In step 33, the moving average value VMn of the subtraction value VLn is calculated based on the above equation (6) to reduce the random noise added to the subtraction value VLn.
A first average value VMn as shown in waveform (d) of FIG. 8 is obtained.

In step 34, the first average value VMn
Is within the first reference range Vu1.
S "is the case where the first average value VMn is within the first reference range Vu1, so that the detection signal value Vn is noise when the angular velocity sensor 1 is not applied with the angular velocity. The determination is made and the process proceeds to step 35. Then, in step 35, the subtraction value VLn is set to a zero value (see the area a of the waveform (f) in FIG. 18).

On the other hand, if "NO" is determined in the step S34, it means that the first average value VMn has exceeded the first reference range Vu1, so that the angular velocity sensor 1 is truly applied with the angular velocity. It moves to step 36. Then, in step 36, the subtraction value VLn is output as it is (FIG. 22).
(See region b of waveform (f)).

Further, in step 37, the subtraction value VLn set in this way is set to the integrand value VPn, and in step 38, the integrand value VPn is integrated to obtain the measurement value VOn (the waveform in FIG. 18). (G)). And step 39
Then, the offset correction value update setting process shown in FIG. 16 is performed, and the process returns to step S40.

Next, the offset correction value update setting processing of FIG. 16 will be described.

First, in step 41, it is determined whether or not the first average value VMn calculated in step 33 is within the second reference range Vu2, and if it is determined to be "NO" (see the waveform (FIG. 19)). In the area d in (h)), the process returns to the step 45, and if it is determined to be "YES" (see the area c in the waveform (h) in FIG. 19), the step 42 is executed to update and set the offset correction value V03. The following processing is performed.

In step 42, the detected signal value Vn output from the angular velocity sensor 1 is read as the correction reference value VRn ', and in step 43, the moving average of the correction reference value VRn' is calculated as shown in the following equation (8). Is obtained.

Further, at step 44, the second average value VSn 'is used as an offset correction value V03 to calculate the subtraction value of the second average value VSn'.
And the process returns in step 45.

Next, based on the waveform diagrams shown in FIGS. 17 to 19, the specific operation of the angular velocity measuring apparatus according to the present embodiment will be described in relation to the processing in FIGS.

First, the upper waveform (A) in FIG. 17 shows the detection signal value V output from the angular velocity sensor 1 to the arithmetic circuit 22.
n and waveform (b) represent the offset correction value V03 output from the offset correction value updating circuit 29 to the subtraction circuit 22, and waveform (c) represents the subtraction value VLn output from the subtraction circuit 22.

The waveform (d) in the upper part of FIG. 18 is the waveform (e) of the first average value VMn output from the first smoothing circuit 23 obtained by moving-averaging the subtraction value VLn as shown in the equation (7). Is the first determination signal VN output from the first determination circuit 24,
The waveform (f) shows the integrand value VPn output from the integrand value output circuit 25, and the lower waveform (g) shows the measured value VOn which is the integration result output from the integration circuit 26.

Further, the upper waveform (h) in FIG. 19 shows the subtraction value VLn output from the subtraction circuit 22, the waveform (h) shows the second determination signal VQ output from the second determination circuit 27,
The waveform (nu) moves the correction reference value VRn 'to the correction reference value VRn' read into the second smoothing circuit 28 in response to the second judgment signal VQ, and the lower waveform (R) as shown in the above equation (8). On average, the second average value V output from the second smoothing circuit 28
Sn 'is shown.

First, the detection signal value Vn of the waveform (a) in FIG. 17 is a waveform on the upper right with the drift signal D due to temperature change, aging degradation, and the like as an inclination. In addition, random noise is superimposed on a portion where no angular velocity is applied.

As a result of the processing in step 32, the detection signal value V
A subtraction value VLn is obtained by subtracting the offset correction value V03 of the waveform (b) from n. Next, in the process of step 33, a moving average of equation 7 is calculated to reduce the noise component, and a waveform having a high frequency such as the first average value VMn of the waveform (d) is removed to remove the noise component. To reduce.

In the processing of steps 34 to 37, when the first average value VMn is within the first reference range Vu1, that is, in the regions a and a, the first judgment signal V shown in the waveform (e) is obtained.
N is output from the first determination circuit 24 to the integrand value output circuit 25. The integrand value output circuit 25 receives the first determination signal VN and sets the subtraction value VLn to a zero value. The subtracted value VLn is output from the integrand value output circuit 25 to the integrand value VPn.
Is output to the integration circuit 26 (see waveform (f)).

On the other hand, when the first average value VMn is outside the reference range Vu1, that is, in the region b, the first determination signal V
Since N is not output, the integrand output circuit 25 receives the first determination signal VN and outputs the subtraction value VLn as it is.
Ln is output to the integration circuit 26 as the integrand value VPn (see waveform (f)).

On the other hand, the offset correction value update setting processing of FIG. 16 will be described based on the waveform diagram shown in FIG.

In step 41, when the subtraction value VLn calculated in step 32 is within the second reference range Vu2, that is, in the regions c and c, as shown in the waveform (i), the second
Is output to the second smoothing circuit 28. The second smoothing circuit 28 receives the second determination signal VQ and corrects the detection signal value Vn output from the angular velocity sensor 1 via the A / D conversion circuit 2 by a correction shown in a waveform (nu). The arithmetic operation of Expression 8 is performed on the reference value VRn ', and the obtained second average value VSn' is output to the offset correction value update circuit 29.

Here, the second average value VSn 'output from the second smoothing circuit 28 is obtained by removing a high-frequency waveform.
This is a value from which noise components have been removed. Then, the second average value VSn 'becomes an offset correction value V03 (waveform (b) and waveform (l)).

In the angular velocity measuring apparatus according to the present embodiment having such a configuration, as described above, the drift noise superimposed on the detection signal value Vn can be extracted by correcting the integrand value output, and the offset correction value is updated. Thus, the drift component of the detection signal value Vn can be removed.

Thus, in this embodiment, the first reference range Vu1 in the first determination circuit 24 can be made significantly smaller than the reference range Vt1 in the second embodiment.
As the integrand value VPn output from the integrand value output circuit 25, a value close to the actual angular velocity applied to the arithmetic circuit 21 can be obtained, and the displacement angle θ can be detected with high sensitivity.

Further, in the offset correction value update setting processing, it is determined whether or not the signal of the subtraction value VLn is within the second reference range Vu2. The time difference can be eliminated by the amount that the average calculation is not performed, and the subtraction value VLn output from the subtraction circuit 22 is obtained.
It is possible to reduce the amount of noise inside.

Further, based on FIGS. 20 to 26,
A fourth embodiment according to the present invention will be described.

A feature of the present embodiment is that a preprocessing for setting the second reference range used in the offset correction value update setting processing to be larger than the range in the normal processing at the time of starting the apparatus is performed.

In this embodiment, the same components as those in the above-described second embodiment are denoted by the same reference numerals, and description thereof will be omitted.

A second reference numeral 31 designates a second reference range Vu2 for setting the second reference range Vu2.
The second reference range setting circuit 31 is connected to the storage circuit 17A of the second determination circuit 17 that performs an offset correction value update setting process. Also,
The second reference range setting circuit 31 changes the second reference range Vt2 to a large signal value A from when a main switch (not shown) for starting the device is closed until the reference time T0 elapses. After the time elapses, the signal value is set to the normal signal value B (A> B). Then, as shown in FIG. 21, the second reference range setting process is performed as a pre-process of the integrand value output process and the offset correction value update setting process described above.

Here, the operation of the offset correction value update setting processing according to the present embodiment will be described based on the processing program shown in FIG.

First, at step 61, it is detected whether or not the main switch is closed, and the process waits at step 61 until the main switch is closed.

If "YES" is determined in the step 61, the process proceeds to a step 62, where the timer T is reset and started.

In step 63, the timer T determines whether the reference time T
0 has elapsed, and in step 63, “YE
If "S" is determined, the process proceeds to step 64 since the reference time T0 has elapsed. In step 64, the second reference range Vt2 is set to the signal value B, and the routine proceeds to step 66 and returns.

On the other hand, if "NO" is determined in the step 63, the process proceeds to the step 65 since the reference time T0 has not yet elapsed. In step 65, the second reference range Vt2 is set to a signal value A larger than the signal value B, and the routine proceeds to step 66 and returns.

Next, a specific operation of the angular velocity measuring device according to the present embodiment will be described with reference to the waveform diagrams shown in FIGS. Since each of the waveforms (a) to (nu) is a waveform at the same position as in the above-described second embodiment, description of each waveform is omitted, and only the characteristic portions will be described.

First, in the waveform (a) showing the detection signal value Vn, a disturbance of the waveform of the angular velocity sensor 1 appears in the area e from the start of the apparatus to the elapse of the reference time T0.

On the other hand, as shown in the waveform (h), the second reference range Vt2 in the second determination circuit 17 is a large signal until the reference time T0 elapses by the second reference range setting circuit 31. The signal value is set to the value A, and after the elapse of the reference time T0, the signal value is set to the normal signal value B.

Thus, in the offset correction value update setting processing, the offset correction value V02 'can be set to a waveform close to the detection signal value Vn in the region e where the waveform (a) is disturbed. A certain signal value can be treated as noise. As a result, the signal value can be set to zero in the region e of the integrand value VPn output from the integrand value output circuit 25.

Thus, in this embodiment, the noise at the time of starting the apparatus can be reliably removed, the detection error at the time of starting the apparatus can be reduced, and the displacement angular velocity can be detected with high sensitivity.

In the fourth embodiment, the second reference range setting processing corresponding to the preprocessing is performed for the second embodiment. However, as shown in FIG. A second reference range setting circuit 31 'may be connected to the storage circuit 27A of the used second determination circuit 27. In this case, the parentheses in steps 64 and 65 in the processing program in FIG. May be performed.

Further, in the fourth embodiment, the second reference range Vt2 (Vu2) is switched in two stages with the passage of time. However, the present invention is not limited to this, and the second reference range Vt2 (Vu2) is not limited to this.
(Vu2) may be set to decrease sequentially.

Further, in each of the above embodiments, the case where the angular velocity sensor 1 for detecting the angular velocity is used as the external force detecting means has been described. However, the present invention is not limited to this. Good.

[0150]

As described above in detail, according to the first aspect of the present invention, the offset correction value is subtracted from the detection value output from the external force detection means by the subtraction means, and the subtraction value is smoothed by the smoothing means. Output as an average value, it is possible to smooth the random noise superimposed on the detection value and reduce the peak value of the noise. The determining means determines whether or not an external force is acting on the external force detecting means. If the external force is not acting, the integrand is set to zero. Output as a value. As a result, the integrand value in which the random noise is reduced can be output from the integrator value output means to the integrator means, and an accurate measurement value can be obtained from the integrator means.

Furthermore, by reducing the random noise in the subtraction value by the smoothing means, the criterion of the judgment means can be set low, and the integrand output from the integrand output means can be used as the external force detection means. Can be made to have a waveform close to the external force applied to the surface.

Therefore, when an angular velocity sensor such as a gyro is used as the external force detecting means, an accurate displacement angle can be measured by integrating the integrand with the integrating means.

According to the second aspect of the present invention, in addition to the integrand output processing according to the first aspect of the present invention, processing for updating an offset correction value when subtraction is performed by the subtracting means is added. It is determined whether or not to update using the first average value output from the means, and when it is determined to update, the second average value obtained by smoothing the detected value is updated and set as the offset correction value. Thereby, in the subtraction means,
By subtracting the constantly updated offset correction value from the detected value, the drift component in the detected value can be reduced, and the integrand close to the external force applied to the external force detecting means is directed from the integrand output means to the integrating means. Can be output.

According to a third aspect of the present invention, in addition to the integrand output processing according to the first aspect of the present invention, a process of updating an offset correction value when subtraction is performed by the subtraction means is added. It is determined whether the subtracted value falls within a second reference range. If it is determined that the value falls within the range, a second average value obtained by smoothing the detected value is updated and set as an offset correction value. Thereby, in the subtraction means,
By subtracting the constantly updated offset correction value from the detected value, the drift component in the detected value can be reduced,
An integrand close to the external force applied to the external force detection means can be output from the integrand value output means to the integration means.

According to the fourth aspect of the present invention, the second reference range in the second determination means is set to be large when the apparatus is started up, and the second reference range is set to be small after the lapse of the reference time. Can be output stably, and error measurement at the time of startup can be prevented.

[Brief description of the drawings]

FIG. 1 is a functional block diagram showing the invention of claim 1;

FIG. 2 is a functional block diagram showing the invention of claim 2;

FIG. 3 is a functional block diagram showing the invention of claim 3;

FIG. 4 is a circuit diagram showing a configuration of an angular velocity measuring device according to a first embodiment.

FIG. 5 is a flowchart showing an integrand value output process according to the first embodiment.

FIG. 6 is a waveform diagram illustrating a detection value output from an angular velocity sensor and a subtraction value output from a subtraction circuit.

FIG. 7 is a waveform diagram illustrating an average value output from a smoothing circuit, a determination signal output from a determination circuit, an integrand value output from an integrand value output circuit, and a measurement value output from an integration circuit.

FIG. 8 is a circuit diagram showing a configuration of an angular velocity measuring device according to a second embodiment.

FIG. 9 is a flowchart showing an integrand output process according to the second embodiment.

FIG. 10 is a flowchart showing an offset correction value update setting process according to the second embodiment.

FIG. 11 shows a detection value output from an angular velocity sensor, an offset correction value output from an offset correction value update circuit,
FIG. 6 is a waveform chart showing a subtraction value output from a subtraction circuit.

FIG. 12 illustrates a first average value output from a first smoothing circuit, a first determination signal output from a first determination circuit, an integrand output from an integrand output circuit, and an integration circuit. It is a waveform diagram which shows the measured value output.

FIG. 13 receives the first average value output from the first smoothing circuit, the second determination signal output from the second determination circuit, and the second determination signal, and reads them into the second smoothing circuit. FIG. 9 is a waveform chart showing a correction reference value to be output and a second average value (offset correction value) output from a second smoothing circuit.

FIG. 14 is a circuit diagram showing a configuration of an angular velocity measuring device according to a third embodiment.

FIG. 15 is a flowchart showing measured value output processing according to a third embodiment.

FIG. 16 is a flowchart showing an offset correction value update setting process according to the third embodiment.

FIG. 17 shows a detection value output from an angular velocity sensor, an offset correction value output from an offset correction value update circuit,
FIG. 6 is a waveform chart showing a subtraction value output from a subtraction circuit.

FIG. 18 shows a first average value output from a first smoothing circuit, a first determination signal output from a first determination circuit, an integrand output from an integrand output circuit, and an output from an integration circuit. It is a waveform diagram which shows the measured value output.

FIG. 19 is a diagram illustrating a subtraction value output from a subtraction circuit, a second determination signal output from a second determination circuit, and a correction reference read from an angular velocity sensor into a second smoothing circuit in response to the second determination signal. FIG. 9 is a waveform chart showing values and a second average value (offset correction value) output from a second smoothing circuit.

FIG. 20 is a circuit diagram showing a configuration of an angular velocity measuring device according to a fourth embodiment.

FIG. 21 is a flowchart showing overall processing according to a fourth embodiment.

FIG. 22 is a flowchart showing a second reference range setting process according to the fourth embodiment.

FIG. 23 shows a detection value output from an angular velocity sensor, an offset correction value output from an offset correction value update circuit,
FIG. 6 is a waveform chart showing a subtraction value output from a subtraction circuit.

FIG. 24 is a diagram illustrating a first average value output from a first smoothing circuit, a first determination signal output from a first determination circuit, an integrand value output from an integrand value output circuit, It is a waveform diagram which shows the measured value output.

FIG. 25 receives the first average value output from the first smoothing circuit, the second determination signal output from the second determination circuit, and the second determination signal, and reads them into the second smoothing circuit. FIG. 9 is a waveform chart showing a correction reference value to be output and a second average value (offset correction value) output from a second smoothing circuit.

FIG. 26 is a circuit diagram of an angular velocity measuring device showing a modification according to the fourth embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Angular velocity sensor (external force detection means) 2 A / D conversion circuit 3,11,21 Operation circuit 4,12,22 Subtraction circuit 5 Smoothing circuit 6 Judgment circuit 7,15,25 Integrated value output circuit 8,16,26 Integration Circuit 9 Signal output circuit 13,23 First smoothing circuit 14,24 First determination circuit 17,27 Second determination circuit 18,28 Second smoothing circuit 19,29 Offset correction value update circuit 31,31 ' 2 reference range setting circuit

Claims (4)

[Claims] 1. An external force detecting means for detecting an external force applied to an object to be measured as a detection signal, a subtraction means for subtracting an offset correction value from a detection value of a detection signal output from the external force detection means, A smoothing unit that outputs the output subtraction value as a smoothed average value; a determination unit that determines whether or not an external force is acting on the external force detection unit using the smoothed average value; When it is determined that no external force is applied, a zero value is output as an integrand value, and when it is determined that an external force is applied, a subtraction value output from the subtraction means is output as an integrand value. Means for integrating the integrand output from the integrand output means;
An external force measuring device comprising an integrating means for outputting an integration result as a measured value. 2. An external force detecting means for detecting an external force applied to an object to be measured as a detection signal, a subtraction means for subtracting an offset correction value from a detection value of a detection signal output from the external force detection means, A first smoothing unit that outputs the output subtraction value as a smoothed first average value, and a second determination unit that determines whether an external force is acting on the external force detection unit using the first average value. The first determining means and the first determining means output a zero value as an integrand when it is determined that no external force is acting, and are output from the subtracting means when it is determined that an external force is acting. An integrand value output means for outputting a subtraction value as an integrand value, and integrating an integrand value output from the integrand value output means,
Integrating means for outputting an integration result as a measured value; second determining means for determining whether to update an offset correction value when subtracting by the subtracting means by using the first average value; A second smoothing means for outputting the detected value output from the external force detecting means as a smoothed second average value when it is determined by the second determining means that the offset correction value is to be updated; And an offset correction value updating means for updating the second average value output from the second average value as an offset correction value of the subtracting means. 3. An external force detecting means for detecting an external force applied to an object to be measured as a detection signal, a subtraction means for subtracting an offset correction value from a detection value of a detection signal output from the external force detection means, A first smoothing unit that outputs the output subtraction value as a smoothed first average value, and a first smoothing unit that determines whether an external force is acting on the external force detection unit. First determining means for determining whether or not the output first average value is within a predetermined first reference range; and the first determining means determines that the first average value is equal to the first average value. When it is determined that the value falls within the reference range, a zero value is output as the integrand value. An integrand value output means for outputting as Integrating the integrand value outputted from the output means,
Integrating means for outputting an integration result as a measurement value; and a subtraction value output from the subtraction means for determining whether to update an offset correction value when subtraction is performed by the subtraction means. A second determining means for determining whether or not the value falls within a second reference range; and when the second determining means determines that the subtraction value is within a second reference range, the second force is output from the external force detecting means. A second smoothing means for outputting a smoothed detection value as a second average value, and offset correction for updating the second average value output from the second smoothing means as an offset correction value for the subtraction means. An external force measuring device comprising a value updating means. 4. The external force measurement device according to claim 3, wherein the second reference range in the second determination means is set larger than a range during normal processing when the device is started.