JPH11190743A - Tri-axial acceleration detector for mobile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To to provide a tri-axial acceleration detector for mobile which can produce a corrected X-axis acceleration signal by eliminating the effect of X-axis component of gravitational acceleration. SOLUTION: A tilt detecting means 6 determines the tilt angle and direction of a mobile, based on the output from a tri-axial speed sensor 1, especially a Z-axis acceleration signal. A gravitational acceleration component operating means 5 determines the X-axis component of gravitational acceleration, based on the tilt angle and direction, and produces an X-axis gravitational acceleration signal Vgx corresponding to X-axis component of gravitational acceleration. A correction operating means 8 adds the X-axis gravitational acceleration signal Vgx to an X-axis acceleration signal VX of subtracts the signal Vgx therefrom to produce a corrected X-axis acceleration signal VX' from which an error component caused by a gravitational acceleration component incident to the tilt of the mobile is removed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-axis acceleration detector mounted on a moving body, and more particularly to a three-axis acceleration capable of outputting a corrected X-axis direction acceleration signal in which the influence of gravitational acceleration is corrected. The present invention relates to a detection device.

[0002]

2. Description of the Related Art In a car navigation system for a car, the travel distance of the car is calculated in order to specify the position of the car. Various methods of calculating the traveling distance have been proposed. Among them, an acceleration signal in the traveling direction obtained from the three-axis acceleration detecting device (assuming that the X-axis direction of the three-axis acceleration sensor is coincident with the X-axis direction of the vehicle, that is, the traveling direction, is referred to as an X-axis acceleration signal hereinafter. ) Is used to calculate the mileage of an automobile. When using such a calculation method, the accuracy of the X-axis direction acceleration signal determines the calculation accuracy of the traveling distance.

[0003]

However, as a three-axis acceleration sensor used in a three-axis acceleration detecting device, an X-axis component and a Y-axis component of acceleration acting on the weight in response to deformation of a diaphragm to which the weight is fixed are described. X-axis direction acceleration signal, Y-axis direction acceleration signal,
It has been found that when a three-axis acceleration sensor that outputs an axial acceleration signal is used, the calculation accuracy of the traveling distance deteriorates.

This is because, when the vehicle is traveling on a slope, the X-axis direction component of the gravitational acceleration acting on the weight is added to the X-axis direction acceleration component of the acceleration detected by the three-axis acceleration sensor. . That is, on an uphill, the X-axis acceleration component detected by the three-axis acceleration sensor becomes smaller by the X-axis component of the gravitational acceleration, and on a downhill, the three-axis acceleration sensor becomes smaller by the X-axis component of the gravitational acceleration. X to detect
This is because the axial acceleration component increases.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a three-axis acceleration detector for mounting on a moving body, which can obtain a corrected X-axis direction acceleration signal in which the influence of the gravitational acceleration component in the X-axis direction is removed.

Another object of the present invention is to provide a three-axis acceleration detecting device for mounting on a moving body, which can detect an inclination angle and an inclination direction from an output of a three-axis acceleration sensor without separately providing an inclination detecting means. To provide.

[0007]

SUMMARY OF THE INVENTION The present invention provides an X-axis component and a Y-axis component of acceleration acting on a weight in response to deformation of the diaphragm caused by acceleration acting on the weight fixed to the diaphragm. And X corresponding to the Z-axis direction component
A three-axis acceleration sensor that outputs an axial acceleration signal, a Y-axis acceleration signal, and a Z-axis acceleration signal is provided. The three-axis acceleration sensor is mounted on the moving body so that the X axis of the three-axis acceleration sensor is along the traveling direction of the moving body. The object of improvement is a three-axis acceleration detector for mounting on a moving object. The diaphragm is generally made of metal, but its material is arbitrary. In general, the outer peripheral portion of the diaphragm is supported by the pedestal so as to form a space that allows displacement or movement of the weight subjected to the acceleration. As the triaxial acceleration sensor, various sensors such as a sensor utilizing a change in capacitance and a sensor using a piezoelectric ceramic substrate which generates spontaneous polarization charges when subjected to stress can be used.

[0008] In general, a moving object is an automobile,
It is a vehicle such as a motorcycle and a bicycle, and the moving body may move without driver. In the case of an automobile, the traveling direction of the moving body is the front-back direction in which the chassis extends, and the three-axis acceleration sensor is preferably installed at the center of the chassis.

In the present invention, a tilt detecting means for obtaining a tilt angle and a tilt direction of the moving body is used. The tilt detecting means may be of a mechanical type or may be of a type which electrically detects a tilt angle and a tilt direction, and may have any configuration. However, if the inclination detecting means that can determine the inclination angle and the inclination direction of the moving body is used based on the outputs (the X-axis direction acceleration signal, the Y-axis direction acceleration signal, and the Z-axis direction acceleration signal) of the three-axis acceleration sensor. Since it is not necessary to prepare physically separate tilt detecting means, not only the configuration is simplified, but also the overall size can be made compact.

[0010] The output of the triaxial acceleration sensor includes information on the tilt angle and the tilt direction of the moving body. Looking at the case where the angle of the X axis of the moving body (a virtual axis extending in the traveling direction of the moving body) (the angle at which the X axis inclines with respect to the horizontal axis or the horizontal plane) changes, the moving body tilts the X axis. When the vehicle starts moving or returns from the inclined state to the horizontal state (for example, when the car starts climbing a slope or finishes a slope), the Z-axis acceleration signal includes the slope. A corresponding signal change appears. When a change in the signal of one polarity occurs at the beginning of the ascending, a change in the signal of the other polarity occurs at the end of the ascending. This means that when viewed from an automobile, the acceleration in the Z-axis direction changes between the time when the front wheel enters the slope and the time when the rear wheel enters the slope, or the time when the front wheel passes through the slope and the time when the rear wheel passes through the slope. That's why. There is a direct proportional relationship between the peak value of this change and the change amount θ of the inclination angle. Specifically, in a case where the moving body has no inclination on the Y axis and has an inclination only on the X axis, a relationship of peak value = k (θ / 2) occurs. Here, k is a constant.

To obtain tilt information from the Z-axis direction acceleration signal, it is necessary to remove noise. Most of the noise is noise based on vibration applied when the moving body moves. Since this kind of noise is known to have a high frequency, a predetermined frequency (for example, 10
Hz or 5 Hz) or more, and a Z-axis direction low frequency signal VLZ is obtained. Then, the peak value of the change in the signal appearing in the Z-axis direction low frequency signal VLZ is obtained, and the change in the tilt angle and the tilt direction are detected from the peak value. When the acceleration signal in the Z-axis direction is obtained based on the spontaneous polarization charge generated in the piezoelectric ceramic substrate, the spontaneous polarization charge disappears when the stress applied to the piezoelectric ceramic substrate stops changing. At the time of the change, at the end of the inclination, a pulse-like signal change having a peak appears in the Z-axis direction low frequency signal VLZ. Therefore, it is easy to detect the peak value. When using the output of a three-axis acceleration sensor that detects acceleration using a change in capacitance, the Z-axis direction low frequency signal VLZ is used at the start of inclination, when the inclination angle is changed, and at the end of inclination. Therefore, the low-frequency signal VLZ in the Z-axis direction may be differentiated using a differentiating circuit to obtain a peak value from the differentiated signal. However, in practice, the Y-axis of the moving body is generally inclined, so it is necessary to determine the inclination angle in consideration of the inclination of the Y-axis.

In the case of using a three-axis acceleration sensor using a piezoelectric ceramic substrate, the inclination detecting means firstly removes a high frequency component generated by vibration or the like from the X-axis direction acceleration signal and the Z-axis direction acceleration signal. A band filter for outputting the frequency signal VLX and the Z-axis direction low frequency signal VLZ is provided. Then, the peak value of the low-frequency signal VLZ in the Z-axis direction output from the bandpass filter is detected by the peak value detecting means. Next, the cumulative peak value storage means accumulates the sequentially detected peak values while sequentially adding or subtracting them according to the polarity, and stores the accumulated peak values as a cumulative peak value Vip. For example, if the peak value of a signal change generated when the moving body starts climbing on a straight slope having a constant inclination angle that causes only the X-axis inclination of the moving body is + Vp, the slope ends. The peak value generated at this time is -Vp, and when this value is accumulated, Vp-Vp = 0, and the inclination angle at that time becomes 0. Therefore, it becomes possible to detect the inclination angle and the inclination direction of the moving object based on the accumulated peak value. However, since the moving object actually has a Y-axis inclination, the X-axis inclination angle θx and the inclination direction of the X-axis of the moving object are obtained from the X-axis direction low frequency signal VLX and the accumulated peak value Vip when the peak value is detected. Are determined. The tilt direction and tilt angle determining means obtains a tilt angle θx by arctan (Vip / VLX),
The inclination direction is determined based on the polarity of the accumulated peak value Vip.

In the present invention, the gravitational acceleration component calculation means includes:
The X-axis direction component of the gravitational acceleration is obtained based on the tilt angle and the tilt direction detected as described above, and an X-axis direction gravitational acceleration signal corresponding to the X-axis direction component of the gravitational acceleration is output.
The correction calculating means adds or subtracts the X-axis direction gravitational acceleration signal to or from the X-axis direction acceleration signal to remove an error caused by a gravitational acceleration component generated by the inclination of the moving body, and thereby removes an error component. Is output. As the X-axis direction acceleration signal used in this calculation, a signal from which high frequency components (noise) have been removed, such as the above-described X-axis direction low frequency signal, is used to increase accuracy.

As in the present invention, the X-axis direction component of the gravitational acceleration is obtained, and the X-axis direction gravitational acceleration signal is added to or subtracted from the X-axis direction acceleration signal to remove an error caused by the gravitational acceleration component. When the corrected X-axis direction acceleration signal can be output, there is an advantage that the calculation accuracy of the speed and the moving distance is increased.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram showing an example of an embodiment in a case where the three-axis acceleration detecting device for mounting on a moving body of the present invention is used for a navigation system of an automobile. In FIG. 1, reference numeral 1 denotes a three-axis acceleration sensor. The basic configuration of the three-axis acceleration sensor is as shown in FIG. In the figure, reference numeral 11 denotes a sensor body, which is an X-axis acceleration detection electrode for detecting X-axis acceleration, a Y-axis acceleration detection electrode for detecting Y-axis acceleration, and a Z-axis acceleration. An electrode pattern 12 including a Z-axis direction acceleration detecting electrode is formed on the front surface, and a counter electrode pattern 13 facing the electrode pattern 12 is formed on the back surface.
The piezoelectric ceramic substrate 14 includes a portion between the electrode for detecting the axial acceleration and the electrode for detecting the Z-axis acceleration and the counter electrode pattern 13 which is polarized. The piezoelectric ceramic substrate 14 is joined to a diaphragm 15 made of metal or glass via an epoxy-based adhesive. A weight 16 is fixed to the center of the diaphragm 15 via an appropriate bonding means such as an adhesive. An outer peripheral portion of the diaphragm 15 is supported by a pedestal 17 configured to allow displacement (movement) of the weight 16. Although not shown, an X-axis direction acceleration signal, a Y-axis direction acceleration signal, and a Z-axis acceleration signal corresponding to the X-axis direction component, the Y-axis direction component, and the Z-axis direction component of the acceleration acting on the weight 16 are shown.
A processing circuit that outputs an axial acceleration signal is provided to constitute a three-axis acceleration sensor. The basic principle of this type of three-axis acceleration sensor is described in International Publication WO93.
/ 02342 (PCT / JP92 / 00882).

The three-axis acceleration sensor 1 shown in FIG.
It is arranged at the center of the vehicle chassis such that the axial direction (a virtual axis extending along the direction in which the two X-axis direction acceleration detection electrodes are arranged) is the traveling direction of the vehicle (the front-rear direction of the vehicle chassis). The output of the triaxial acceleration sensor 1 includes information on the inclination angle and the inclination direction of the vehicle. Looking at the case where the angle of the X axis of the automobile (the angle at which the X axis is inclined with respect to the horizontal axis or the horizontal plane) changes, when the automobile starts climbing a hill or finishes a hill, the acceleration signal in the Z-axis direction is obtained. A change in the signal corresponding to the inclination appears in VZ. In order to obtain inclination information from the Z-axis direction acceleration signal VZ, it is necessary to remove noise. Most of the noise is noise generated due to vibration generated when the automobile is running. Since it is known that this type of noise has a high frequency, the band-pass filter 2 is used to obtain a low-frequency signal VLZ in the Z-axis direction from which frequency components higher than a predetermined frequency (10 Hz or 5 Hz) have been removed. In this example, the X-axis direction acceleration signal V
X also removes noise by the bandpass filter 2.

Low-frequency signal VLZ in the Z-axis direction without noise
The change in the signal appearing in the above indicates the inclination angle and the inclination direction of the vehicle. As shown in FIGS. 3A and 3B,
When the vehicle starts climbing the slope, a change in the signal P1 of one polarity occurs in the Z-axis low frequency signal VLZ. Then, at the time when the vehicle finishes the uphill, a change in the signal P2 of the other polarity occurs in the Z-axis low frequency signal VLZ. In terms of the relationship between the car and the slope, this is the Z-axis between the time the front wheel of the car enters the slope and the rear wheel enters the slope, or the time the front wheel passes the slope and the rear wheel passes the slope. This is because a change occurs in the acceleration in the direction (vertical direction). There is a direct proportional relationship between the peak value of the change of the signals P1 and P2 and the change Δθ of the inclination angle. Specifically, there is no inclination in the Y-axis of the automobile (the direction orthogonal to the X-axis direction and the horizontal direction when the front-rear direction of the chassis is the X-axis direction), and there is an inclination only in the X-axis. In the case where there is an inclination only between the X axis and the horizontal axis or the horizontal plane HL), a relationship of Vp = k (θ / 2) occurs between the peak value Vp of the signals P1 and P2 and the inclination angle θ. Here, k is a constant. However, actually, the slope is also inclined in the Y-axis direction, and the automobile is generally inclined not only in the X-axis direction but also in the Y-axis direction. It is necessary to determine the inclination angle.

When the acceleration signal in the Z-axis direction is obtained based on the spontaneous polarization charge generated in the piezoelectric ceramic substrate as in this example, the spontaneous polarization charge disappears when the stress applied to the piezoelectric ceramic substrate stops changing. FIG. 3 (B)
As shown in (D), when the inclination starts, when the inclination angle is changed, and when the inclination ends, the Z-axis direction low frequency signal VLZ has changes in pulsed signals P1 to P4 and P11 to P16 having peaks. Appear. Therefore, a signal having a peak value can be detected without using a signal processing circuit such as a differentiating circuit.

In order to use the three-axis acceleration sensor 1 using a piezoelectric ceramic substrate, as shown in FIG. 1, the Z-axis direction low frequency signal VLZ output from the bandpass filter 2 is input to the peak value detecting means 3 for peak value detection. Find the value. The peak value detecting means 3 can be constituted by a known voltage sampling and holding circuit, and the Z value output from the bandpass filter 2 can be used.
The peak value Vp of the signal P1 and the like included in the axial low frequency signal VLZ and the polarity thereof are detected. For example, the sampling period is 1 to 5 msec, and the period of one signal P1 is, for example, about 50 msec. Therefore, it is possible to detect an almost accurate peak value.

Next, the accumulated peak value storage means 4
The sequentially detected peak values Vp are accumulated while sequentially adding or subtracting according to the polarity, and stored as the accumulated peak values Vip. For example, as shown in FIG. 3A, the peak value of the change in the signal P1 generated when the vehicle starts climbing on a straight slope having a constant inclination angle that causes only the X-axis inclination of the vehicle is + Vp. , The peak value generated when the slope ends is -Vp, and when this is accumulated, Vp-Vp = 0, and the inclination angle at that time is 0.
Becomes Further, as shown in FIG. 3C, when the angle is changed in the middle of the slope, the peak value Vp1 of the first signal P11 is obtained.
1 and the peak value Vp12 of the second signal P12 and the peak value -Vp13 of the third signal P13 are added to obtain Vp11 +
Vp12-Vp13 = 0. When going down a hill, 4
The peak value -Vp14 of the fifth signal P14 and the fifth signal P1
The peak value VP15 of the fifth signal and the peak value VP16 of the sixth signal P16
Are added to make -Vp14 + Vp15 + VP16 = 0. Therefore, it is possible to detect the inclination angle and the inclination direction of the vehicle based on the accumulated peak value Vip and its polarity. The accumulated peak value storage means 4 can be constituted by using, for example, an A / D conversion circuit for converting the output of the peak value detection means 3 into a digital signal, and a microcomputer constituting a counter circuit for adding and subtracting the digital signal. it can. The count value of the counter circuit is stored in the memory of the microcomputer.

Further, there is provided a tilt direction and tilt angle determining means 5 for obtaining a tilt angle θx and a tilt direction of the X axis of the vehicle from the low frequency signal VLX in the X-axis direction when the peak value Vp is detected and the cumulative peak value Vip. ing. The tilt direction and tilt angle determining means 5 determines the tilt angle θx by the equation θx = arctan (Vip / VLX), and determines the tilt direction by the polarity of the accumulated peak value Vip. The tilt direction and tilt angle determining means 5 can be easily configured by using a microcomputer constituting the above-described cumulative peak value storing means 4.

In this example, the bandpass filter 2, the peak value detecting means 3, the accumulated peak value storing means 4, the inclination direction and the inclination angle determining means 5 constitute an inclination detecting means 6 for detecting the inclination angle and the inclination direction of the vehicle. Have been. Although not shown, the storage content of the accumulated peak value storage means 4 is set to 0.
A reset circuit is provided for resetting. Therefore, when this apparatus is started, the reset circuit is operated on level ground to store the accumulated peak value storage means 4.
Should be reset.

In this example, the gravitational acceleration component calculation means 7 calculates the X-axis direction component Gx = Gsin θx of the gravitational acceleration G based on the tilt angle θx detected in this manner, and calculates the X-axis direction component of the gravitational acceleration. An X-axis direction gravitational acceleration signal Vgx corresponding to Gx is output. The X-axis direction gravitational acceleration signal Vgx is given a polarity according to the tilt direction. The gravitational acceleration component calculation means 7 is also configured by using a microcomputer constituting the above-described cumulative peak value storage means 4.

The correction calculating means 8 calculates the acceleration signal V in the X-axis direction.
A corrected X-axis direction acceleration signal VX obtained by adding or subtracting the X-axis direction gravitational acceleration signal Vgx to X or the X-axis direction low frequency signal VLX to remove an error caused by the gravitational acceleration component Gx generated by the inclination of the vehicle. 'Is output. In this example, the X-axis direction low frequency signal VLX is used to increase the calculation accuracy. Specifically, if the vehicle is on an uphill, the corrected X-axis direction acceleration signal VX 'is VX' = VX + Vgx or VX '= VLX + V
gx, and if it is downhill, the corrected X-axis direction acceleration signal VX '
Is calculated as VX '= VX-Vgx or VX' = VLX-Vgx. When the processing circuit of the three-axis acceleration sensor 1 includes a bandpass filter, the bandpass filter 2 is unnecessary, and the X-axis direction acceleration signal becomes the X-axis direction low frequency signal itself.

When the speed and mileage of the automobile are calculated using the corrected X-axis direction acceleration signal VX ', a more accurate speed and mileage can be obtained as compared with the prior art. Therefore, the position detection accuracy of the navigation system equipped with the three-axis acceleration detecting device for mounting a moving body of this example is greatly improved as compared with the related art.

The inclination angle and the inclination direction of the vehicle in the Y-axis direction can also be detected, and the corrected acceleration in the Y-axis direction in which the error caused by the gravitational acceleration component GY caused by the inclination of the vehicle is removed. It is also possible to obtain the signal VY '. In that case, the Y-axis direction acceleration signal is input to the bandpass filter 2 instead of the X-axis direction acceleration signal, and the Y-axis direction low frequency signal VLY is obtained.
LY is input to the tilt direction and tilt angle determining means 5. In the inclination direction and inclination angle determining means 5, θY = arctan (Vip
/ VLY) to determine the inclination angle θY, and determine the inclination direction based on the polarity of the accumulated peak value Vip. The gravitational acceleration component calculating means 7 calculates the gravitational acceleration G component G in the Y-axis direction.
Y = Gsin θY is obtained, and the Y-axis direction gravitational acceleration signal Vgy is obtained in consideration of the inclination direction. Finally, the correction operation means 8
Is the Y-axis direction acceleration signal VY or the Y-axis direction low frequency signal V
A corrected Y-axis direction acceleration signal VY 'obtained by adding or subtracting the Y-axis direction gravitational acceleration signal Vgy to or from LY to remove an error caused by the gravitational acceleration component GY caused by the inclination of the vehicle.
Can be obtained.

In the above example, the inclination detecting means 6 detects the inclination angle and the inclination direction of the vehicle by using the output signal of the triaxial acceleration sensor 1. However, the present invention is not limited to the case where the inclination detecting means 6 for detecting the inclination angle and the inclination direction of the vehicle using the output signal of the three-axis acceleration sensor 1 is used. Alternatively, a tilt detecting means for detecting a tilt angle and a tilt direction of the automobile and outputting a signal may be used. Further, data of the inclination angle and the inclination direction of the vehicle may be obtained by using the inclination detecting means having another configuration.

In the above example, a piezoelectric type triaxial acceleration sensor using a piezoelectric ceramic substrate is used. However, even when a type of triaxial acceleration sensor that detects acceleration based on a change in capacitance is used. The present invention is capable of
The structure and type of the triaxial acceleration sensor are not limited.

[0029]

As in the present invention, the X-axis direction component of the gravitational acceleration is obtained, and the X-axis direction gravitational acceleration signal is added to or subtracted from the X-axis direction acceleration signal, and the error caused by the gravitational acceleration component is calculated. When the corrected corrected X-axis direction acceleration signal can be output, there is an advantage that the calculation accuracy of the speed and the moving distance is increased.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an example of an embodiment in a case where a three-axis acceleration detecting device for mounting a moving object according to the present invention is used for a navigation system of an automobile.

FIG. 2 is a diagram showing a basic structure of a three-axis acceleration sensor used in the embodiment of FIG.

3A is a diagram illustrating an example of a relationship between a car and a slope, FIG. 3B is a diagram illustrating a Z-axis direction low frequency signal VLZ generated in the relationship of FIG. 3A, and FIG. FIG. 3C is a diagram showing another example of the relationship between the car and the slope, and FIG.
(C) The Z-axis direction low frequency signal V generated in the relationship
LZ is shown.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 triaxial acceleration sensor 2 bandpass filter 3 peak value detecting means 4 accumulated peak value storing means 5 tilt direction and tilt angle determining means 6 tilt detecting means 7 gravity acceleration component calculating means 8 correction calculating means

Claims (5)

[Claims] 1. An X-axis component, a Y-axis component, and a Z-axis component of acceleration acting on the weight in response to deformation of the diaphragm caused by acceleration acting on the weight fixed to the diaphragm. X-axis acceleration signal, Y
A three-axis acceleration sensor that outputs an axial acceleration signal and a Z-axis acceleration signal, wherein the three-axis acceleration sensor has a three-axis acceleration sensor mounted on the moving body such that the X axis is along the traveling direction of the moving body. An axial acceleration detecting device, an inclination detecting means for obtaining an inclination angle and an inclination direction of the moving object; and an X-axis direction component of the gravitational acceleration based on the inclination angle and the inclination direction. A gravity acceleration component calculating means for outputting an X-axis direction gravitational acceleration signal corresponding to the X-axis direction component, and adding / subtracting the X-axis direction gravitational acceleration signal to / from the X-axis direction acceleration signal to generate the inclination of the moving body. X that eliminates the error caused by the gravitational acceleration component
A three-axis acceleration detecting device for mounting on a moving object, comprising: a correction calculating means for outputting an axial acceleration signal. 2. An X-axis component, a Y-axis component, and a Z-axis component of acceleration acting on the weight in response to deformation of the diaphragm caused by acceleration acting on the weight fixed to the diaphragm. X-axis acceleration signal, Y
A moving object mounting acceleration, comprising: a three-axis acceleration sensor that outputs an axial acceleration signal and a Z-axis direction acceleration signal, wherein the three-axis acceleration sensor is mounted on the moving object so that the X axis of the three-axis acceleration sensor is along the traveling direction of the moving object. A detection device for obtaining an inclination angle and an inclination direction of the moving body based on an output of the three-axis acceleration sensor; and an X-axis of the gravitational acceleration based on the inclination angle and the inclination direction. A gravitational acceleration component calculating means for obtaining a directional component and outputting an X-axis direction gravitational acceleration signal corresponding to the X-axis direction component of the gravitational acceleration; and adding and subtracting the X-axis direction gravitational acceleration signal to and from the X-axis direction acceleration signal. And a correction X that eliminates an error caused by a gravitational acceleration component generated by the inclination of the moving body.
A three-axis acceleration detecting device for mounting on a moving object, comprising: a correction calculating means for outputting an axial acceleration signal. 3. An X-axis acceleration detection electrode for detecting X-axis acceleration, a Y-axis acceleration detection electrode for detecting Y-axis acceleration, and a Z-axis acceleration detection electrode for detecting Z-axis acceleration. An electrode pattern including the electrode pattern is formed on the front surface, and a counter electrode pattern facing the electrode pattern is formed on the back surface, the X-axis direction acceleration detecting electrode, the Y-axis direction acceleration detecting electrode, and the Z-axis direction acceleration detecting electrode. A piezoelectric ceramic substrate in which a portion between the piezoelectric ceramic substrate and the counter electrode pattern is polarized; a diaphragm to which the piezoelectric ceramic substrate is joined; a weight fixed to the diaphragm; and a weight acting on the weight. An X-axis direction acceleration signal corresponding to an X-axis direction component, a Y-axis direction component, and a Z-axis direction component of acceleration, Y
And a processing circuit for outputting an axial acceleration signal and a Z-axis acceleration signal. The moving body is arranged so that the X-axis of the triaxial acceleration sensor extends along the traveling direction of the moving body. An acceleration detection device for mounting on a moving object, wherein the inclination angle and the inclination direction of the moving object are obtained based on an X-axis acceleration signal and a Z-axis acceleration signal output from the three-axis acceleration sensor. A gravitational acceleration for obtaining an X-axis direction component of the gravitational acceleration based on the inclination angle and the inclination direction, and outputting an X-axis gravitational acceleration signal corresponding to the X-axis direction component of the gravitational acceleration; A component calculating means for adding and subtracting the X-axis direction gravitational acceleration signal to and from the X-axis direction acceleration signal to remove an error caused by a gravitational acceleration component caused by the tilt of the moving body; Correction X
A three-axis acceleration detecting device for mounting on a moving object, comprising: a correction calculating means for outputting an axial acceleration signal. 4. The X-axis direction low frequency signal VLX and the Z-axis direction low frequency signal obtained by removing a high frequency component generated by vibration or the like from the X-axis direction acceleration signal and the Z-axis direction acceleration signal. A band-pass filter that outputs VLZ; peak-value detecting means that detects a peak value of the Z-axis direction low-frequency signal VLZ output from the band-pass filter; and sequentially adds and subtracts sequentially detected peak values according to their polarities. An accumulative peak value storage means for accumulating and storing as an accumulative peak value Vip; and an X-axis tilt of the moving body from the X-axis direction low frequency signal VLX and the accumulative peak value Vip when the peak value is detected. 4. The three-axis acceleration detecting device according to claim 3, further comprising a tilt direction and a tilt angle determining means for obtaining the angle θx and the tilt direction. 5. The tilt direction and tilt angle determining means,
The inclination angle θx is obtained by arctan (Vip / VLX),
The three-axis acceleration detecting device according to claim 3, wherein the inclination direction is determined based on the polarity of the accumulated peak value Vip.