JP3352547B2 - Position detection 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 position detecting method for detecting the position of various objects to be detected, such as detecting the position of an underground object such as a buried pipe from the surface of the earth in the field of civil engineering, and more particularly to measuring the magnetic field strength. The present invention relates to a method of detecting a position.

[0002]

2. Description of the Related Art As a position detecting method for detecting the position of an underground object such as a buried pipe from the surface of the ground, the strength of a magnetic field generated by a magnetic field generating means disposed on an object to be detected such as an underground object is measured. A position detection method of a magnetic field strength measurement method of measuring by a magnetic detection element arranged at an observation point and detecting a position of an object to be detected from the measured value of the magnetic field strength is already known,
This is disclosed in JP-A-57-133373 and JP-A-59-133373.
No. 153112.

In the position detecting method disclosed in Japanese Patent Application Laid-Open No. 57-133373, a magnetic field generating means is attached to an object to be detected so that the center line of magnetic force is vertical, and the magnetic field generated by the magnetic field generating means is perpendicular to the object. The components are scanned and measured by a magnetic detection element having a horizontally arranged magnetic detection surface, and the position of the object to be detected is detected from the center position of the circle drawn by the locus of the point where the measured value shows the minimum value.

In the position detecting method disclosed in Japanese Patent Application Laid-Open No. 59-153112, a magnetic field generating means is attached to an object to be detected so that the center line of magnetic force is in a vertical direction, and a linkage surface (magnetic detection surface) is vertical. The magnetic detection element is reciprocated in a direction penetrating the intersecting plane at a right angle, and the position of the object to be detected is detected from the position where the magnetic field intensity measured by the magnetic detection element shows a minimum value in the moving process. .

[0005]

Problems to be Solved by the Invention
In the position detection method disclosed in Japanese Patent No. 73, the magnetic field intensity must be measured many times by changing the measurement position so that the point where the measured value shows the minimum value is drawn in a circle. A great deal of time and effort is required to detect the position of an object, and if an object is planted on the ground and an obstacle such as a tree, a card rail, or a telephone pole is present, the position of the detected object may not be detected.

In the position detecting method disclosed in Japanese Patent Application Laid-Open No. 59-153112, the relative position relationship of the interlinking surface of the magnetic detecting element with respect to the direction of the center line of magnetic force of the magnetic field generated by the magnetic field generating means is described. If the moving direction and the like are not set correctly, accurate position detection is not performed, and measurement may be performed without satisfying these conditions, resulting in erroneous detection.

If an obstacle exists directly above the object to be detected, the position of the object cannot be detected, and only the position directly above the object can be detected. Direction cannot be detected. For this reason, for example, when connecting a branch pipe to a sewage main pipe without excavation when burying an underground pipe, it is not possible to determine in which direction the excavation should be performed from the construction start position.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and it is possible to accurately and directionally detect a direction in which a detected object is located from an arbitrary position without being affected by an obstacle. It is an object of the present invention to provide a position detection method using a magnetic field strength measurement method that can detect a signal efficiently and without any labor.

[0009]

According to a first aspect of the present invention, there is provided a position detecting method, wherein the intensity of a magnetic field generated by a magnetic field generating means arranged on an object to be detected is arranged at an observation point. In a position detection method of measuring a magnetic detection element and detecting the position of the detected object from the measured magnetic field strength, a plurality of magnetic detection elements having a magnetic detection surface aligned on the same plane are used. The orientation of the magnetic field generating means and the magnetic sensing element are adjusted so that the magnetic field strength measurement values detected by the magnetic sensing elements are both minimum, and It is characterized by detecting the position of an object to be detected.

In order to achieve the above object, a position detecting method according to a second aspect of the present invention supplies an electric signal to a magnetic field generating means disposed on an object to be detected, and detects a magnetic field generated by the magnetic field generating means at an observation point. A position detecting method for detecting the position of the object to be detected from an output signal of the magnetic detecting element, wherein a plurality of magnetic detecting surfaces are aligned on the same plane. The magnetic field generation means and the magnetic detection element using a magnetic detection element so that the phases of output signals output from the plurality of magnetic detection elements are simultaneously inverted with respect to the phase of an electric signal supplied to the magnetic field generation means. The position of the object to be detected is detected from the direction indicated by the alignment direction of the magnetic detection elements.

[0011]

According to the position detecting method of the present invention, when the measured values of the magnetic field intensities of the plurality of magnetic detecting elements both become minimum by adjusting the arrangement posture of the magnetic field generating means and the magnetic detecting element, the magnetic field generating means is activated. The magnetic detection surface of the magnetic detection element is aligned with the same plane as the plane including the central magnetic field line of the generated magnetic field. Accordingly, at this time, the direction indicated by the alignment direction of the magnetic detection elements indicates the position of the detection target, and the position of the detection target, particularly, the direction in which the detection target is located from the observation point is detected.

In the position detecting method according to the second aspect, when the magnetic detecting surface of the magnetic detecting element is aligned with the same plane as the plane including the center line of magnetic force of the magnetic field generated by the magnetic field generating means, the output signal of the magnetic detecting element is output. Utilizing that the phase is simultaneously inverted with respect to the phase of the electric signal supplied to the magnetic field generating means, and a plurality of magnetic detecting elements output by adjusting the arrangement posture of the magnetic field generating means and the magnetic detecting element. When the phase of the output signal is simultaneously inverted with respect to the phase of the current supplied to the magnetic field generating means at the same time, the direction indicated by the alignment direction of the magnetic detection elements indicates the position of the detection target, and the position of the detection target, In particular, the direction in which the detected object is located is detected from the observation point.

Here, the phase inversion means that the phase of the output signal output from the magnetic detecting element is the same as that of the electric signal supplied to the magnetic field generating means.
Producing an 80 degree phase difference or vice versa.

[0014]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of an embodiment of the present invention. FIG. 1 shows an embodiment of a position detecting device used in the embodiment of the position detecting method according to the present invention. In FIG. 1, reference numeral 1 denotes a buried pipe to be detected buried in the ground, and a mobile trolley 2 is inserted into the buried pipe 1 to be detected. A wheel rotation sensor (not shown) such as a rotary encoder is connected to the wheels 3 of the movable trolley 2, and a signal output from the wheel rotation sensor is transmitted to a control device 5 via a signal line 4.

The control device 5 measures the moving distance of the movable carriage 2 in the detected buried pipe 1 based on a signal from the wheel rotation amount sensor described above. A transmission coil 6 as a magnetic generating means is mounted on the movable trolley 2 so as to be rotatable around the same axis as the center axis X of the buried pipe 1 to be detected by an attitude control means 7. The transmission coil 6 is supplied with an AC voltage from a signal supply device 8 such as an oscillator via a power line 9, and generates a magnetic field in which the center line of magnetic force Mc extends in a direction orthogonal to the center axis X at any rotational displacement position.

At the observation point on the ground, a magnetic detector 10 is movably arranged. The magnetism detecting device 10 is rotatable about the axis parallel to the central axis X of the buried pipe 1 to be detected by the base 11 and the moving means 12 on the base 11, and is a direction that penetrates its plate surface at a right angle. And a substrate 13 provided so as to be able to move in parallel. The substrate 13 has a lower receiving coil 14 and an upper receiving coil 1 as magnetic sensing elements.
5, the respective magnetic detection surfaces 14a and 15a are on the same plane,
In this case, they are vertically aligned and fixed so as to be arranged on one plane parallel to the plate surface of the substrate 13.

Lower receiving coil 14 and upper receiving coil 15
Each measures the magnetic field strength, and the measurement signal is a signal line 16,
It is transmitted by 17 to measuring devices 18, 19. Measuring instrument 1
Numerals 8 and 19 have magnetic field strength meters 20 and 21, respectively, and the magnetic fields measured by the lower receiving coil 14 and the upper receiving coil 15 based on measurement signals input from the lower receiving coil 14 and the upper receiving coil 15, respectively. Magnetic field strength meter 2
Indicated by 0 and 21. When detecting the position, the magnetic detection surfaces 14 of the lower receiving coil 14 and the upper receiving coil 15 are used.
a, 15a through the center of each of the magnetic sensing surfaces 14a, 1a.
The movable carriage 2 is moved so that the center of the transmission coil 6 is located at the intersection of the plane orthogonal to 5a and the central axis X of the buried pipe 1 to be detected.

In this state, as shown in FIG. 2, the direction of the center line of magnetic force Mc of the transmission coil 6 and the magnetic detection surfaces 14a, 14a,
5a, the lower receiving coil 14 and the upper receiving coil 15 are mounted on the substrate while the magnetic field radiating surface 6a of the transmitting coil 6 is not orthogonal to the magnetic detecting surfaces 14a and 15a. 13, when the plate surface is translated in a direction perpendicular to the plate surface, that is, as shown by an arrow A in FIG. 2, the central magnetic field line Mc of the transmitting coil 6 and the lower receiving coil are moved as shown in FIG. 14. Upper receiving coil 1
The minimum value of the magnetic field strength measured by the lower receiving coil 14 and the upper receiving coil 15 according to the angle formed between the magnetic detection surfaces 14a and 15a of the No. 5 is the actual center position of the transmitting coil 6 (the position of the center magnetic field line Mc). It appears at a more shifted position, and the measurement position of the minimum value appears at a different position between the lower receiving coil 14 and the upper receiving coil 15.

Here, the measured values of the lower receiving coil 14 and the upper receiving coil 15 can simultaneously take the minimum value because the lower receiving coil 14 and the lower receiving coil 14
This is the case where the magnetic detection surfaces 14a and 15a of the upper receiving coil 15 are located. At this time, the magnetic field radiation surface 6a of the transmission coil 6 is orthogonal to the magnetic detection surfaces 14a and 15a.

Next, the procedure for implementing the position detecting method according to the present invention will be described with reference to FIGS. FIG. 4 shows a procedure for implementing the position detecting method according to the present invention. First, the transmitting coil 6 is rotationally displaced around the central axis X of the buried pipe 1 to be detected by the attitude control means 7 (step 10). A rotational displacement position at which the magnetic field intensity measured by 14 becomes a minimum value is found (step 20), and the rotational displacement of the transmitting coil 6 is stopped at the rotational displacement position (step 3).
0).

As a result, as shown in FIG. 5A, the magnetic fields of the lower receiving coil 14 and the upper receiving coil 15 are set on a plane parallel to the plane including the center line of magnetic force Mc of the magnetic field generated by the transmitting coil 6. The detection surfaces 14a and 15a are aligned, and the magnetic field emission surface 6a of the transmission coil 6 and the magnetic detection surfaces 14a and 15a
and a are orthogonal. Note that the mutual attitude adjustment of the transmitting coil 6, the lower receiving coil 14, and the upper receiving coil 15 is performed as follows.
Lower receiving coil 1 together with substrate 14 by moving means 12
4. The upper receiving coil 15 may be rotationally displaced.

Next, it is determined whether the measured value of the magnetic field strength by the upper receiving coil 15 is the minimum value (step 40). If not, the moving means 12 moves the lower receiving coil 14, the upper receiving coil together with the substrate 14 by the moving means 12. 15 is translated (step 50), the direction of displacement is determined based on the behavior of the magnetic field intensity measurement value by the upper receiving coil 15, and the translation direction is selectively set (step 60). The position where the value becomes the minimum value is found, and the parallel movement of the lower receiving coil 14 and the upper receiving coil 15 is stopped at the parallel movement position (step 70).

Next, it is checked whether the measured values of the magnetic field strength of the lower receiving coil 14 and the upper receiving coil 15 are both minimum values (step 80), and the magnetic field strength of the lower receiving coil 14 and the upper receiving coil 15 is checked. If the measured values are not both the minimum values, the process returns to step S10, and the mutual attitude adjustment of the transmitting coil 6, the lower receiving coil 14, and the upper receiving coil 15 is performed again.

Lower receiving coil 14 and upper receiving coil 15
When both of the measured magnetic field strength values of FIG.
As shown in FIG.
This means that the magnetic detection surfaces 14a and 15a of the lower receiving coil 14 and the upper receiving coil 15 are located above. In this state, the alignment direction of the lower receiving coil 14 and the upper receiving coil 15 indicates the center of the buried pipe 1 to be detected, whereby the buried pipe 1 can be located from any observation point on the ground. Direction is detected.

FIG. 6 shows an embodiment of the position detecting device used in the embodiment of the position detecting method according to the second aspect.
In FIG. 6, parts corresponding to those in FIG. 1 are denoted by the same reference numerals as those in FIG. 1, and description thereof is omitted. In this embodiment, the lines of magnetic force generated by the transmitting coil 6 enter from the front side of the magnetic detection surfaces of the lower and upper receiving coils 14 and 15, and enter from the direction orthogonal to the magnetic detection surfaces. The phase of the output signals output by the lower and upper receiving coils 14 and 15 with respect to the electric signal supplied to the transmitting coil 6 changes between when entering from the back side of the surface, and the lines of magnetic force generated by the transmitting coil 6 are lower and lower. The magnetic field lines generated by the transmitting coil 6 are different from the lower and upper receiving coils 1 when entering from the front side of the magnetic detection surfaces of the upper receiving coils 14 and 15.
The fact that the phases of the output signals of the lower and upper receiving coils 14 and 15 with respect to the electric signal are inverted between the case where the signals enter from the back side of the magnetic detection surfaces 4 and 15 is used.

Therefore, in this embodiment, the measuring devices 18, 1
Reference numerals 9 each input a reference signal having the same phase as the AC voltage supplied to the transmission coil 6 from the signal supply device 8 through the signal transmission cable 20, and receive the lower reception coil 14 and the upper reception coil 1.
5 detects the direction of the phase shift of the output voltage with respect to the AC voltage supplied to the transmission coil 6 by synchronous detection of each output voltage and the reference signal, and displays these directions on the screen display units 21 and 22.

In this case, if the phase of the output voltage output from the lower receiving coil 14 and the upper receiving coil 15 is the same as the phase of the AC voltage supplied to the transmitting coil 6 by the synchronous detection, the positive half of the output voltage is output. When a wave is obtained, and the phases of the output voltages output by the lower receiving coil 14 and the upper receiving coil 15 have a phase difference of 180 degrees with respect to the phase of the AC voltage supplied to the transmitting coil 6 , A half-wave in the negative direction is obtained, and the phase of the output voltage of the lower receiving coil 14 and the phase of the output voltage of the upper receiving coil 15 are inverted with respect to the phase of the AC voltage supplied to the transmitting coil 6 by the polarity determination of the half-wave. Can be detected. At the time of position detection, the magnetic detection surfaces 14 a and 15 of the lower receiving coil 14 and the upper receiving coil 15 are used.
a at a point of intersection of a plane orthogonal to the magnetic detection surfaces 14a and 15a through the center of the
The carriage 2 is moved so that the center of the transmission coil 6 is located.

In this state, as shown in FIG. 2, the direction of the center line of magnetic force Mc of the transmission coil 6 and the magnetic detection surfaces 14a, 14a,
5a, the lower receiving coil 14 and the upper receiving coil 15 are mounted on the substrate while the magnetic field radiating surface 6a of the transmitting coil 6 is not orthogonal to the magnetic detecting surfaces 14a and 15a. 13, when the plate surface is translated in a direction perpendicular to the plate surface, that is, as shown by an arrow A in FIG. 2, the center magnetic line of force Mc of the transmitting coil 6 and the magnetic detecting surfaces of the lower receiving coil 14 and the upper receiving coil 15 are moved. 14a, 15
As shown in FIGS. 7A and 7B, the phases of the output voltages of the lower receiving coil 14 and the upper receiving coil 15 are supplied to the transmitting coil 6 in accordance with the angle formed by the a. With respect to the phase of the voltage, the position appears at a position shifted from the actual center position of the transmitting coil 6 (the position of the center line of magnetic force Mc),
The position also appears at a different position between the lower receiving coil 14 and the upper receiving coil 15 according to the distance between the lower receiving coil 14 and the upper receiving coil 15.

Here, the reason why the phases of the output voltages of the lower receiving coil 14 and the upper receiving coil 15 are simultaneously inverted with respect to the phase of the AC voltage supplied to the transmitting coil 6 is that the transmitting coil 6 has a center line of magnetic force Mc. And the magnetic detection surfaces 14a and 15a of the lower receiving coil 14 and the upper receiving coil 15 are positioned at this time.
And the magnetic detection surfaces 14a and 15a are orthogonal to each other.

Next, the procedure for implementing the position detecting method according to the present invention will be described with reference to FIGS. FIG. 8 shows a procedure for implementing the position detection method according to the present invention. First, the transmitting coil 6 and the transmitting coil 6 are moved downward from the phase shift direction of the output voltage displayed on the screen display sections 21 and 22 of the measuring instruments 18 and 19. The direction of deviation from the side and upper receiving coils 14 and 15 is determined (step 10), and the transmitting coil 6 is rotationally displaced around the central axis X of the buried tube 1 to be detected by the attitude control means 7 (step 20).

Under this rotational displacement, a rotational displacement position at which the phase of the output voltage output from the lower receiving coil 14 is inverted with respect to the phase of the AC voltage supplied to the transmitting coil 6 is found (step 20). Transmit coil 6 at position
Is stopped (step 40). This allows
As shown in FIG. 5A, the magnetic detection surfaces 1 of the lower receiving coil 14 and the upper receiving coil 15 are on a plane parallel to a plane including the center line of magnetic force Mc of the magnetic field generated by the transmitting coil 6.
4a and 15a are aligned, and the magnetic field line emission surface 6 of the transmission coil 6
a and the magnetic detection surfaces 14a and 15a are orthogonal to each other.

The mutual orientation of the transmitting coil 6, the lower receiving coil 14, and the upper receiving coil 15 is adjusted by the moving means 12 together with the substrate 14 and the lower receiving coil 14,
The upper receiving coil 15 may be rotationally displaced. Next, it is determined whether or not the phase of the output voltage of the upper receiving coil 15 is inverted with respect to the phase of the AC voltage supplied to the transmitting coil 6 (step 50). , 19, the direction of the shift between the transmitting coil 6 and the lower and upper receiving coils 14, 15 is determined from the direction of the phase shift of the output voltage displayed on the screen display units 21, 22 (step 60). The lower receiving coil 14, the upper receiving coil 1 together with the substrate 14 by the moving means 12
5 (step 70), and the upper receiving coil 1
5, a position where the phase of the output voltage is inverted with respect to the phase of the AC voltage supplied to the transmission coil 6 is detected, and the parallel movement of the lower receiving coil 14 and the upper receiving coil 15 is stopped at the parallel movement position (step). 80).

Next, it is confirmed that the phases of the output voltages of the lower receiving coil 14 and the upper receiving coil 15 are both inverted with respect to the phase of the AC voltage supplied to the transmitting coil 6 (step 90). 14 and upper receiving coil 1
5 is not inverted with respect to the phase of the AC voltage supplied to the transmission coil 6, the process returns to step 10, where the transmission coil 6 and the lower reception coil 14 and the upper reception coil 15 Perform the mutual posture adjustment again. When the phases of the output voltages of the lower receiving coil 14 and the upper receiving coil 15 are both inverted with respect to the phase of the AC voltage supplied to the transmitting coil 6, as shown in FIG. This means that the magnetic detection surfaces 14a and 15a of the lower receiving coil 14 and the upper receiving coil 15 are located on the center line of magnetic force Mc.

In this state, the lower receiving coil 14
The direction in which the detection and buried pipe 1 is aligned with the upper receiving coil 15 indicates the center of the detected and buried pipe 1, whereby the direction in which the detected and buried pipe 1 is located from any observation point on the ground is detected.
In the above-described embodiment, the phase inversion is determined based on the phases of the output voltages of the lower receiving coil 14 and the upper receiving coil 15 and the phase of the AC voltage supplied to the transmitting coil 6. The current may be shifted by a different degree. The position detecting method according to the present invention is not limited to detecting the position of an underground pipe, and may be used for detecting the position of various other objects to be detected.

[0035]

As will be understood from the above description, according to the position detecting method of the present invention, the direction in which a detected object is located from an arbitrary observation point can be greatly improved regardless of the presence or absence of an obstacle. The detection can be performed accurately without requiring a lot of time and labor. Therefore, for example, in the case of burial of underground pipes, when branch pipes are connected to the sewage main pipe without excavation, it is possible to accurately determine in which direction the excavation should be performed from the construction start position, and the excavation direction Easy,
Can be determined quickly and accurately.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram showing one embodiment of a position detecting device used for implementing a position detecting method according to the present invention.

FIG. 2 is an explanatory diagram showing a state in which a magnetic field radiation surface of a transmission coil is not orthogonal to a magnetic detection surface of a reception coil.

FIG. 3 is a graph showing the relationship between the measured values of the magnetic field strength of the lower receiving coil and the upper receiving coil and the position of the receiving coil in a state where the magnetic field radiation surface of the transmitting coil is not orthogonal to the magnetic detection surface of the receiving coil.

FIG. 4 is a flowchart showing a procedure for implementing a position detection method according to the present invention.

FIGS. 5A and 5B are explanatory diagrams showing a state in which a magnetic flux emission surface of a transmission coil and a magnetic detection surface of a reception coil are orthogonal to each other.

FIG. 6 is a system configuration diagram showing one embodiment of a position detecting device used for implementing the position detecting method according to the present invention.

FIGS. 7A and 7B are diagrams respectively showing the phase inversion positions of the output voltages of the lower receiving coil and the upper receiving coil when the magnetic field radiation surface of the transmitting coil and the magnetic detecting surface of the receiving coil are not orthogonal to each other; 7 is a graph showing a relationship with a position of a receiving coil.

FIG. 8 is a flowchart showing a procedure for implementing a position detection method according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Buried pipe to be detected 2 ... Moving truck 3 ... Wheels 4 ... Signal line 5 ... Control device 6 ... Transmission coil 7 ... Attitude control means 8 ... Signal supply device 9 ... Power line 10 ... Magnetic detection device 11 ... Base 12 ... Moving Means 13 ... Board 14 ... Lower receiving coil 15 ... Upper receiving coil 16, 17 ... Signal line 18, 19 ... Measuring instrument 20, 21 ... Magnetic field strength meter

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-57-133373 (JP, A) JP-A-59-153112 (JP, A) JP-A-5-126962 (JP, A) JP-A-4- 350296 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01V 3/10 F16L 1/024 G01B 7/00

Claims (2)

(57) [Claims] An intensity of a magnetic field generated by a magnetic field generating means arranged on an object to be detected is measured by a magnetic detecting element arranged at an observation point, and a position of the object to be detected is detected from a measured value of the magnetic field intensity. In the position detection method, using a plurality of magnetic sensing elements arranged with the magnetic sensing surface aligned on the same plane, so that the magnetic field intensity measurement values detected by the plurality of magnetic sensing elements are both minimum values, A position detecting method, comprising: adjusting an arrangement posture of the magnetic field generating unit and the magnetic detection element; and detecting a position of the detection target from a direction indicated by an alignment direction of the magnetic detection element. 2. An electric signal is supplied to a magnetic field generating means disposed on an object to be detected, a magnetic field generated by the magnetic field generating means is detected by a magnetic detecting element disposed at an observation point, and an output of the magnetic detecting element is output. What is claimed is: 1. A method for detecting a position of an object to be detected from a signal, comprising: a plurality of magnetic sensing elements having magnetic sensing surfaces aligned on the same plane; The orientation of the magnetic field generating means and the magnetic sensing element is adjusted so that the signal phase is simultaneously inverted with respect to the electric signal supplied to the magnetic field generating means. A position detection method, comprising detecting a position of an object to be detected.