JPH08240611A - Calibrating device for three-axis accelerometer - Google Patents

Abstract

PURPOSE: To make it possible to perform calibration simply in a short time by setting X and Y axes at the specified slant angles with respect to a horizontal plane under the state, wherein the Z axis of a three-axial accelerometer becomes parallel with the horizontal plane, and providing a calibrating plane, which supports a supporting body under this state. CONSTITUTION: A case body 1 comprises seven planes, and accelerometers 2, 3 and 4 for detecting the acceleration in the directions of X, Y and Z axes are fixed to a bottom plane 1a. A calibrating plane 1b is orthogonal to the bottom plane 1a and has the angle of 45 degrees in both directions of X and Y axes. At first, the bottom plane 1a is set on the horizontal plane. The X and Y axes are made parallel with the horizontal plane, and the Z axis is made orthogonal with the horizontal plane. The accelerometers 2 and 3 are set at an output 0, and the output of the accelerometer 4 is calibrated to gravity 1G. Then, the calibrating plane 1b is set on the horizontal plane, the X and Y axes are set at 45 degrees with the horizontal plane and the Z axis is set in parallel with the horizontal plane. The accelerometers 2 and 3 are calibrated to the output 0 and 707G, and the accelerometer 4 is calibrated to the output 0. In this way, the calibration can be quickly performed without removing the accelerometers 2, 3 and 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-axis accelerometer calibration apparatus for calibrating a three-axis accelerometer for measuring the magnitude of three-dimensional vibration.

[0002]

2. Description of the Related Art Accelerometers are used in various fields as vibration detectors, but in order to guarantee their detection accuracy, they are checked by periodically checking them as in the case of general measuring instruments. Calibration is required for items with reduced accuracy. Conventionally, as a method of calibrating the static characteristics of the accelerometer, a method of utilizing the gravitational acceleration 1G of the earth disclosed in Japanese Patent Laid-Open No. 3-216557 is known.

That is, a gravitational acceleration of 1 G is applied by vertically installing an accelerometer to be calibrated on a horizontal plane whose level is ensured sufficiently, and then the accelerometer is rotated by 90 ° from this state. Then, the measurement direction is made horizontal and the gravitational acceleration is set to zero for calibration.

[0004]

If there is only one accelerometer, it can be easily calibrated by the above-mentioned method. However, in the case of a three-axis accelerometer that simultaneously measures three-axis directions, acceleration is performed on one support. Since the three gauges are fixed, according to the above-mentioned calibration method, the accelerometers must be rotated by 90 ° with respect to the detection axis direction.

However, the external structure of the support body which can be accurately rotated by 90 ° with respect to the three-axis directions makes it difficult to use the three-axis accelerometer and is practically difficult to employ. Therefore, conventionally, each acceleration sensor has to be removed from the support body, taken out to the outside, and calibrated one by one, which requires a lot of trouble and time for the calibration.

An object of the present invention is to solve the above-mentioned problems in the prior art and to provide a calibration device for a three-axis accelerometer capable of performing calibration by a simple operation in a short time.

[0007]

To achieve the above object, the present invention provides a first accelerometer for detecting acceleration in a first axial direction, and a first accelerometer forming a right angle with respect to the first axis. A second accelerometer for detecting acceleration in the second axial direction, and a third accelerometer for detecting acceleration in the third axial direction that is orthogonal to the first axis and the second axis. In a three-axis accelerometer fixed to a support,
The first axis and the second axis were each inclined by 45 degrees with respect to the horizontal plane in the state where the axis was parallel to the horizontal plane, and a calibration surface for supporting the support in this state was provided.

Further, according to the present invention, a first accelerometer for detecting acceleration in a first axial direction and a second accelerometer for detecting acceleration in a second axial direction perpendicular to the first axis. A triaxial structure in which an accelerometer and a third accelerometer that detects acceleration in a third axial direction that is perpendicular to the first axis and the second axis are fixed to a support body. A first accelerometer connected to the support and orthogonal to the first axis;
And a second calibration surface which is connected to the support and is orthogonal to the second axis, and which makes an angle of 45 degrees with a horizontal plane and makes a surface contact with the first calibration surface. A first receiving surface and a second receiving surface that faces the first receiving surface at an angle of 45 degrees with respect to a horizontal plane and is in surface contact with the second calibration surface.
And a pedestal having a receiving surface.

[0009]

When installed on a horizontal plane, the gravitational acceleration applied to the longitudinal and lateral acceleration sensors is zero, and the vertical acceleration sensor is applied with gravitational acceleration 1G.

By accelerating the operation directions of the acceleration sensor in the front-rear direction and the left-right direction with respect to the horizontal plane by 45 degrees and making the operation direction of the acceleration sensor in the vertical direction the same as the horizontal plane, the acceleration sensor in the front-rear direction and the left-right direction. Gravity acceleration of 0.707 G is applied to each of them, and the acceleration sensor in the vertical direction has zero gravity acceleration.

As described above, calibration can be performed by rotating the acceleration sensors in the three-axis directions only once at the same time.

[0012]

The present invention will be described below with reference to the illustrated embodiments. FIG. 1 is a perspective view of a triaxial accelerometer according to a first embodiment of the present invention. In this figure, 1 is a box-shaped support (hereinafter referred to as a box) that supports an accelerometer, 2 is an accelerometer for detecting acceleration in the X-axis direction, and 3 is acceleration in the Y-axis direction orthogonal to the X-axis direction. Is an accelerometer that detects acceleration in the Z-axis direction orthogonal to the X-axis and Y-axis directions. The box 1 is composed of seven planes as shown in the figure. Of these, a plane formed by the Y-axis and a bottom surface perpendicular to the Z-axis is indicated by reference numeral 1a, and a calibration surface described later is indicated by reference numeral 1b. Has been done. The accelerometers 2, 3 and 4 are fixed to the bottom surface 1a. The calibration surface 1b is a surface formed perpendicular to the bottom surface 1a and having an angle of 45 degrees with respect to both the X axis and the Y axis.

Next, a method of calibrating the triaxial accelerometer shown in FIG. 1 will be described with reference to FIGS. In this embodiment,
Calibration is performed by placing the box body 1 on the horizontal surface 6 by bringing the calibration surface 1b into contact with the horizontal surface 6 as shown in FIG.
In such a state (state shown in FIG. 2), the Z-axis shows the horizontal plane 6 because of the angular relationship between each axis and the bottom surface 1a and the calibration surface 1b.
, And the X and Y axes are horizontal planes 6 and 45, respectively.
It will make an angle of degrees. Calibration in this state will be described with reference to FIG.

FIG. 3 is a diagram for explaining the principle of calibration in this embodiment. FIG. 3A shows a state in which the accelerometer A is placed on the horizontal plane H. When the accelerometer A has the X axis and the Y axis as detection axes, the gravity acting on the accelerometer A is 0G. Therefore, calibrate so that the output becomes 0. If the accelerometer A has the Z axis as the detection axis, the gravity acting on the accelerometer A is -1 G (because the direction is downward, it is a negative sign), so its output corresponds to this. Calibrate so that the specified value is reached. Further, FIG. 3B shows a state in which the accelerometer A is rotated by 90 degrees from the state shown in FIG. In this state, the Z axis becomes parallel to the horizontal plane H, and X
The axis and the Y-axis have an inclination of 45 degrees with respect to the direction of gravity (thus also an inclination of 45 degrees with respect to the horizontal plane H). in this case,
When the acceleration A has the Z axis as the detection axis, the acting gravity is 0 G, so the output is calibrated to be 0. On the other hand, when the accelerometer A has the X axis and the Y axis as detection axes, the acting gravity is 0.707 G (1 / √2
Since G), the output is calibrated so as to have a value corresponding to this.

As is clear from the above description of FIG. 3, FIG.
3 corresponds to the state shown in FIG. 3A, and the state shown in FIG. 2 corresponds to the state shown in FIG. 3B. Therefore, when calibration is performed by the apparatus of this embodiment, the accelerometers 2 and 3 are set in the state shown in FIG. 1 (the X axis and the Y axis are parallel to the horizontal plane 6 and the Z axis is perpendicular to the horizontal plane 6). , The output is 0, and the accelerometer 4 is calibrated so that the output corresponds to gravity-1G. Next, in the state shown in FIG. 2 (the X-axis and the Y-axis have an inclination of 45 degrees with the horizontal plane 6 and the Z-axis is parallel to the horizontal plane 6), the accelerometers 2 and 3 output 0.7gravity gravity 0.707G. Calibrate so that the output corresponds to.

As described above, in this embodiment, since the calibration surface 1b is formed on the box body 1, the three accelerometers 2, 3, and 4 are combined into one.
It is possible to perform the calibration by a simple operation and in a short time without removing the labor and time of removing each one from the box body 1, performing the calibration, and reattaching it to the box body 1. Furthermore,
When the calibration itself is regularly requested to another person, in the apparatus of this embodiment, if the outputs of the accelerometers 2, 3 and 4 are checked in the state shown in FIG. 1 and the state shown in FIG. It is possible to judge whether or not is necessary, so that only those who need calibration need to be asked to another person, compared to the case where the calibration of all three-axis accelerometers is requested regularly, The cost of calibration can be reduced.

FIG. 4 is a perspective view of a triaxial accelerometer according to the second embodiment of the present invention. In FIG. 4, 2, 3 and 4 are shown in FIGS.
The same accelerometer as shown in. 8 is a box body having a vertical calibration plane 8b _1, 8b ₂ on the bottom surface 8a and the bottom 8a. A processing device 9 processes the outputs of the accelerometers 2, 3 and 4. Accelerometers 2, 3 and 4 are fixed to the bottom surface 8a, and the accelerometers 2 and 3 are the X-axis, which is the detection axis thereof,
It is fixed so as to be parallel to the Y axis and the bottom surface 8a, and the accelerometer 4 is fixed so that its detection axis Z axis is perpendicular to the bottom surface 8a. The relationship between each of these detection axes and the bottom surface 8a is the same as in the previous embodiment, but in this embodiment, the accelerometers 2, 3, 2 are used.
The mutual positional relationship of 4 is different from that of the previous embodiment. The calibration surfaces 8b ₁ and 8b ₂ are formed perpendicularly to the bottom surface 8a as described above, and are also formed in a mutually orthogonal relationship.

FIG. 5 is a perspective view of a pedestal used for calibration of the three-axis accelerometer shown in FIG. In this figure, 10 is a pedestal, 10a is a bottom surface (horizontal surface) of the pedestal, 10b ₁ and 10
b ₂ indicates a receiving surface. The receiving surfaces 10b ₁ and 10b ₂ are bottom surfaces 1
It is formed to have an inclination of 45 degrees with respect to 0a. Therefore, the angle between the receiving surface 10b ₁ and the receiving surface 10b ₂ is 90
It is degree.

FIG. 6 shows the calibration method of the three-axis accelerometer of this embodiment.
Will be described with reference to. Since the relationship between the respective detection axes of the accelerometers 2, 3 and 4 and the bottom surface 8a is the same as that in the previous embodiment, the accelerometers 2, 3 with the bottom surface 8a in contact with the horizontal plane.
Is calibrated by observing the output for gravity 0G, and the accelerometer 4 is calibrated by observing the output for gravity -1G.

Next, as shown in FIG. 6, with the bottom surface 10a of the pedestal 10 being a horizontal surface, the box body 8 is calibrated on its calibration surface 8.
It is placed on the pedestal 10 so that b ₁ and 8b ₂ are in contact with the receiving surfaces 10b ₁ and 10b ₂ of the pedestal 10. Each accelerometer 2, 3,
Since the respective detection axes of _No. 4 and the bottom surface 8a and the calibration surfaces 8b ₁ and 8b ₂ have the above-described angular relationship, the detection axis X of the accelerometer 2 and the detection axis Y of the accelerometer 3 are 45 degrees with respect to the horizontal plane. An angle is formed, and the detection axis Z of the accelerometer 4 is parallel to the horizontal plane. Therefore, the relationship between each detection axis and the horizontal plane is the same as the state shown in FIG. 2 of the previous embodiment, and the accelerometers 2 and 3 are calibrated against the gravity of 0.707G and the accelerometer 4 in the same manner.
Calibrates for gravity 0G.

The effect of this embodiment is the same as that of the previous embodiment, but there is also the effect that the shape of the box 8 can further simplify the effect.

In the description of each of the above-described embodiments, the box body is described as an example for fixing each accelerometer, but if the relationship among the detection axes, the bottom surface, and the calibration surface is as described above, Obviously, it does not have to be a box.

[0023]

As described above, in the present invention, when the axis of one of the three accelerometers is parallel to the horizontal plane, the axes of the other two accelerometers are 45 degrees with respect to the horizontal plane. Since an angled surface or pedestal is provided, it is possible to quickly calibrate the 3-axis accelerometer with simple operation without removing and mounting each accelerometer. Judgment can be made easily and quickly.

[Brief description of drawings]

FIG. 1 is a perspective view of a triaxial accelerometer according to an embodiment of the present invention.

FIG. 2 is a diagram showing a state during calibration of the triaxial accelerometer shown in FIG.

FIG. 3 is a diagram showing accelerations of the single-axis three-axis accelerometer shown in FIG. 1 at normal time and at calibration.

FIG. 4 is a perspective view of a triaxial accelerometer according to another embodiment of the present invention.

5 is a perspective view of a pedestal on which the triaxial accelerometer shown in FIG. 4 is placed.

6 is a diagram showing a state during calibration of the triaxial accelerometer shown in FIG.

[Explanation of symbols]

 1 Box 1b Side of box used for calibration 2,3,4 Acceleration sensor 8 Box 10 Cradle

Claims (2)

[Claims] 1. A first accelerometer for detecting acceleration in a first axis direction, and a second accelerometer for detecting acceleration in a second axis perpendicular to the first axis. A three-axis accelerometer configured by fixing to a support a third accelerometer that detects acceleration in a third axis direction that is perpendicular to the first axis and the second axis, In the state where the third axis is parallel to the horizontal plane, the first axis and the second axis are inclined by 45 degrees with respect to the horizontal plane, and a calibration surface for supporting the support in this state is provided. A calibration device for a three-axis accelerometer characterized in that 2. A first accelerometer for detecting acceleration in a first axis direction, and a second accelerometer for detecting acceleration in a second axis direction perpendicular to the first axis. A three-axis accelerometer configured by fixing to a support a third accelerometer that detects acceleration in a third axis direction that is perpendicular to the first axis and the second axis, A first calibration surface that is connected to the support and is orthogonal to the first axis and a second calibration surface that is connected to the support and is orthogonal to the second axis are provided. A first receiving surface forming an angle of degree and in surface contact with the first calibration surface, and a surface facing the second calibration surface facing the first receiving surface at an angle of 45 degrees with respect to a horizontal plane. A calibration device for a three-axis accelerometer, comprising a pedestal having a second receiving surface that comes into contact with the pedestal.