JP3339731B2 - Hole bending measurement method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring the bending of a hole (including a pipe) by a probe equipped with an accelerometer and a gyro. Therefore, a three-axis accelerometer and three
This also includes the case where a probe equipped with an inertial sensor having a three-axis gyro for measuring each angular velocity around the axis is used.

[0002]

2. Description of the Related Art Inclinometers have generally been used to measure the bending of holes. When measuring with this inclinometer, the inclinometer must be stopped.

[0003]

However, since the measurement is stopped at the time of measurement, the measurement can be performed only discretely, and there is a problem that it is difficult to measure the continuous curved shape of the hole. In addition, there is also a problem that a long measurement time is required for performing a procedure of performing measurement by discretely moving the measurement.

Accordingly, an object of the present invention is to provide a measuring method for continuously and accurately measuring a bent state of a hole in a short time.

[0005]

SUMMARY OF THE INVENTION In view of the above, the present invention is a method for measuring the bending of a hole by using a probe equipped with an accelerometer and a gyro, wherein each inclination at the entrance and the end of the hole is measured by the acceleration. The difference between the slope value at the end based on the continuous measurement value and the slope value at the end of the hole measured by the accelerometer is measured by the gyro. A hole bending measurement method is provided, wherein the continuous measurement value is corrected as drift of the gyro having a constant drift rate within a continuous measurement time.

[0006]

The accelerometer measures the two points at the entrance and the end of the hole, and continuously measures with a gyro from the entrance to the end. This gyro is accompanied by an unavoidable measurement error called gyro drift. However, in normal measurement, since the measurement is completed in a short time, the drift rate can be regarded as constant without change. On the other hand, if there is no drift, the measured value of the inclination angle at the end of the hole by the accelerometer should match the inclination value at the end of the gyro, and if there is a difference, it can be regarded as the drift. Drift rate can be calculated by dividing this drift by the time required for measurement. Correcting the measured value by this drift rate enables highly accurate hole bending measurement, and it is a gyro-based measurement, so it can be continuously shortened. Measurement can be done in time.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in more detail with reference to the embodiments shown in the accompanying drawings. FIG. 1 shows an apparatus for carrying out the hole bending measurement method according to the present invention, and the portion indicated by A is an enlarged view. A hole 12 is formed in a vertical or nearly vertical direction formed in the underground 10, and an entrance 12I is located on the surface of the ground, and an end 12E thereof is located in the ground.

In the hole 12, a probe 1 having wheels 24 and having an accelerometer 20 and a gyro 22 mounted therein.
8 runs. Three orthogonal axes X, Y, Z composed of two horizontal axes X, Y and a vertical axis Z, and a rotation angle φ around each axis,
θ and ψ are defined as shown in FIG. The vehicle travels through the hole 12 while being pulled by a tow rope 16 wound on a reel 14 on the ground, and the gyro 22 continuously measures the bending state of the hole 12. At the beginning and end of the measurement, the probe 18 is stopped, and the hole 1 is also measured by the accelerometer 20.
2 is measured. In the following, holes 12 are used for simplicity.
Of the bends, an inclined state that is a rotation angle θ about the Y axis will be described.

FIG. 2 shows the measurement results. The horizontal axis is time t, and the vertical axis is the hole bending angle θ. Curve θ1 is gyro 2
2 is a continuous measurement result of the hole 12 by the measurement time t
The point PI of = 0 and the point PE of the measurement time t = t0 are the measurement results at the entrance 12I and the end 12E of the hole 12 by the accelerometer 20. At the entrance 12I of the hole 12, the measurement results obtained by the gyro 22 and the accelerometer 20 match,
In E, a difference is generated by the angle θD.

This is because the gyro 22 is accompanied by a measurement error called gyro drift. Since the measurement by the accelerometer 20 does not involve such an error, it is reasonable to correct the measurement result by the gyro 22 at the end 12E of the hole 12 to match the measurement result (point PE) by the accelerometer 20. is there.

FIG. 3 shows drift caused by the gyro 22. As described above, since the drift rate may be considered to be constant, the time t required for the measurement by the gyro 22 is calculated.
The drift rate can be calculated by dividing the angle difference θD by 0. Therefore, the drift at each time t is equal to the origin O
And a straight line θ2 passing through the point (t0, θD). By subtracting this drift straight line θ2 from the measurement result curve θ1 by the gyro 22 in FIG. 2, a highly accurate corrected curve θ12 of the hole bending state after gyro drift correction is obtained.

The travel time t and travel distance 1 of the probe 18 in the hole 12 correspond one-to-one with the travel speed of the tow rope 16. That is, l = f (t). Therefore, the curve indicating the hole bending angle θ (curve θ12 in FIG.
Can be obtained also on the horizontal axis. on the other hand,
Referring to the small triangle in which each side of FIG. 1 is dZ, dX, dl, dX = dl · sin θ. Therefore, X = (integral symbol) sin θdl, and the hole bending angle θ and the traveling distance l
Is obtained as a curve similar to FIG. 2 as described above, so that this integration can be performed. As a result, a curve HC ′ as shown in FIG. 4 is obtained. 10 is the end 1 of the hole 12
The length (running distance) up to 2E.

FIG. 5 shows the rectangular coordinates X, (Y,) in FIG.
3 shows a hole bending curve HC due to Z. Referring to the small triangle in FIG. 1, dZ = dl · cos θ, and Z =
(Integral symbol) cos θdl. Since the relationship between the hole bending angle θ and the traveling distance 1 is obtained as a curve similar to FIG. 2 as described above, this integration can be performed. as a result,
The curve HC of FIG. 5 is obtained. Z0 is the entrance 12I of the hole 12
To the end 12E (Z-axis direction).

For the sake of simplicity, the rotation angle θ about the Y axis is
Although only the inclination of the rotation angle φ has been described, the inclination of the rotation angle φ around the other axis can be measured in the same manner, and further, the rotation angle ψ can be measured by using an inertial sensor. You can know. In a rectangular hole (or pipe) 12 of a cross section where rolling of the probe 18 (change of the azimuth angle で は in FIG. 1) does not occur, the probe 18
Only needs to have a gyro 22 for two axes excluding the rotation angle ψ and an accelerometer 20 for two axes.

[0015]

As is apparent from the above description, according to the present invention, the bending state of a hole in a vertical or nearly vertical direction can be measured continuously and in a short time by using a gyro.
In addition, since the inclination of the entrance and the end of the hole is measured by an accelerometer, the drift of the gyro can be corrected by comparison with the measurement data, and a method of measuring a continuous inclination state with high accuracy in a short time can be provided. Becomes

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of a measuring method according to the present invention.

FIG. 2 is an explanatory diagram of a measuring method according to the present invention.

FIG. 3 is an explanatory diagram of a gyro drift.

FIG. 4 is a diagram showing a hole bending state with respect to a hole length coordinate (l) as a result of the measurement method of FIG. 1;

FIG. 5 is a diagram showing a bent state of the hole with respect to the vertical position (Z) of the hole, as a result of the measurement method of FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Underground 12 Hole (Pipe line) 12E Termination 12I Entrance 14 Reel 16 Tow rope 18 Probe 20 Accelerometer 22 Gyro

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G01C 9/00 G01B 21/20 G01C 19/00

Claims (1)

(57) [Claims] 1. A method of measuring a bend of a hole by a probe equipped with an accelerometer and a gyro, wherein each of the slopes at the entrance and the end of the hole is measured by the accelerometer, and the slope between them is continuously measured by the gyro. The difference between the slope value at the end based on the continuous measurement value and the slope value at the end of the hole measured by the accelerometer,
A hole bending measurement method, wherein the continuous measurement value is corrected as a drift of the gyro having a constant drift rate within the continuous measurement time.