JPH03216557A - Method for precise calibration of accelerometer - Google Patents

Abstract

PURPOSE:To set the mounting angle of an accelerometer to about 1.3sec and to calibrate the accelerometer in the accuracy of about 10<-5>G by measuring acceleration while the mounting table of the accelerometer is precisely rotated using a highly accurate stepping motor. CONSTITUTION:The measuring direction of an accelerometer 8 is matched with the direction of the acceleration of gravity and a pulse setting device 1 is adjusted so as to make the indication of a voltmeter 10 max. That is, a highly accurate stepping motor 4 making about one revolution by 1,000,000 pulses is used in order to rotate a mounting disc 7 and, when a position where the indication of the voltmeter 10 becomes max. is determined, the acceleration of gravity of 1G is accurately applied to the accelerometer 8 at that time. Next, when the motor 4 is rotated by 90 deg. by the pulse setting device 1, the measuring direction of the accelerometer 8 becomes right-angled to the straight line connecting the center of gravity of the earth and a measuring point at an angle of about 1.3sec and, therefore, the acceleration of gravity applied in the measuring direction of the accelerometer 8 becomes zero. Finally, when the motor 4 is further rotated by 90 deg., the measuring direction of the accelerometer 8 differs from the direction of the acceleration of gravity by 180 deg. and the acceleration of gravity of -1G is applied to the accelerometer 8.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention is applicable to Sage accelerometers and accelerometers. This article relates to a method for calibrating an inclinometer.

[Conventional technology]

Conventionally, as a method of calibrating the static characteristics of an accelerometer, K and the earth's gravitational acceleration IG have been used, as shown in Figure 4.

That is, the target accelerometer 8 is placed on a horizontal plane whose flatness has been sufficiently determined using a spirit level 1 so that the gravity direction and the measurement direction are inverted, and a gravitational acceleration of -IG is applied to the measurement direction. Next K accelerometer 8
Rotate 90c@ and set the measurement direction horizontally to make the gravitational acceleration zero.

However, recently, various experiments are being planned that take advantage of the weightless conditions of outer space. In these experiments, we investigate the correlation between gravity and various physical phenomena, especially 10-3 to 1
Experiments in a microgravity environment of about 0""5G are considered important. For this reason. An accelerometer capable of measuring about 10 to 10-9 G is required, and a method for calibrating it is also required.

[Problem to be solved by the invention]

If it is a normal accelerometer, it is possible to calibrate it using the conventional method described above, but the sensor used for space experiments can measure very small accelerations of about 10-3 to 10-5G like the accelerometer. When it is necessary to do so, there is a problem in that the conventional methods cannot ensure sufficient accuracy.

In other words, as shown in Figure 3, the mounting angle of the accelerometer is 1
Since even a deviation of 0 seconds causes an acceleration deviation of 10 to 10 G, flatness using a spirit level or the like is insufficient, and calibration with the desired accuracy is impossible.

[Means for solving glandular problems]

The present invention has been made in order to solve the above-mentioned conventional problems, and includes a mounting disk K accelerometer directly connected to a high-precision stepping motor. To precisely control the gravitational acceleration IG and zero gravity state (OG) to the accelerometer
) is applied.

[Effect]

A high-precision stepping motor allows the installation angle of the accelerometer to be controlled with an accuracy of about 2 seconds, reducing the gravitational acceleration to 1
It can be changed with an accuracy of 0"-5G.

〔Example〕

Embodiments of the present invention will be described with reference to FIGS. 1 and 2.

FIG. 1 is a configuration diagram of the calibration device, in which a pulse generator 2 generates pulses corresponding to the number of pulses K set by the arm pulse setter 1, and the pulse generator 2 generates pulses that are transmitted to the stepper motor via the Sade amplifier 3. 4 is driven.

The rotation of the stepping motor 4 is controlled by the bearing 6K via the joint 5.
A well-supported mounting disc 2K is conveyed.

A mounting disk 7KFi accelerometer 8 is attached and its output voltage can be measured by a voltmeter 10 via an amplifier 9.

The specific calibration method is to first align the measurement direction of the accelerometer 8 with the direction of gravitational acceleration as shown in Figure 2 (al K). At this time, adjust the pulse setter 1 so that the indication of the voltmeter 10 is maximum do.

High precision stepping motor 4 is 36 in 1 million mother pulses
Since the rotation angle is about one rotation at 0 degrees, the rotation angle can be controlled every 1.3 seconds per 1/4' lus. Once the position where the voltmeter 10 indicates the maximum is determined, the accelerometer will have an accurate I
The gravitational acceleration of G is added. Next, when the steady motor tie is rotated 90 degrees using the pulse setting device, the accelerometer 8
The measuring direction of is at an angle of 1.
Since it is a right angle with an accuracy of 3 seconds, the gravitational acceleration applied to the measurement direction of the accelerometer 8 becomes zero. Finally, when the stepping motor is further rotated by 90 degrees, the measurement direction of the accelerometer 8 becomes 1800 degrees different from the gravitational acceleration direction, and the gravitational acceleration of -IG is applied to the accelerometer 8. If the output voltages of the accelerometer 8 at the above three angular positions are measured by the voltmeter 10, the output voltages of the accelerometer 8 at IG, OG, and -IG are measured, so the voltage sensitivity of the accelerometer 8 and Zero point is 1
It can be determined with an accuracy of 0-5G.

〔Effect of the invention〕

The mounting angle of the accelerometer from the stepping motor K is 1.3
Because the flP8 allows positioning with accuracy on the order of seconds. 10-5G
Calibration becomes possible with a degree of accuracy.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a calibration device according to an embodiment of the present invention. FIG. 2 is an explanatory diagram of a calibration method using the calibration apparatus of the present invention. FIG. 3 is a diagram showing acceleration deviation due to accelerometer installation error K. FIG. 4 is an explanatory diagram of a conventional calibration method. 1...No4 Luss setting device. 2... Pulse generation a. 3.
...Sir? Amplifier, 4...Stepping motor, 5...
...Joint, 6...Bearing, 7...Mounting disk, 8...
Accelerometer, 9...Amplifier, 10...Voltmeter, 11.
··Level. Figure 3

Claims (1)

[Claims] A method for calibrating an accelerometer characterized by measuring acceleration while accurately rotating an accelerometer mounting base using a high-precision stepping motor.