JP3352549B2 - 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, for example, detecting the position of an underground object such as a buried pipe from the surface of the earth in the field of civil engineering. The present invention relates to a method of detecting a position.

[0002]

2. Description of the Related Art Conventional position detection methods of this type include:
For example, a method of detecting an underground buried object disclosed in JP-A-57-133373 is known. This underground buried object detection method inserts a detection magnetic field generator consisting of an oscillator that supplies an alternating current to a solenoid coil inside an underground pipe or the like,
By moving this to an arbitrary position and moving the magnetometer on the ground surface where the detection magnetic field generator is located, the minimum value of the vertical component of the magnetic field generated in space is measured on the ground surface. The horizontal position and the burial depth of the underground object to be detected are measured.

[0003]

However, in the above-described conventional position detecting method, the magnetic measuring device is not used when implanted on the ground directly above the magnetic field generating element or when there is an obstacle such as a guardrail or a telephone pole. It cannot be moved and measurement becomes impossible, and measurement must be performed many times,
There was a problem that much time and labor was required.

To solve this problem, a method and an apparatus for measuring the horizontal displacement of a tunnel machine described in JP-A-59-153112 are provided. According to the present invention, a magnetic field generating element is mounted on an excavator such that the center line of magnetic force always faces in a vertical direction, and a horizontally fixed linear magnetic field detecting element guide is provided on a substrate arranged on the ground. A magnetic field detecting device having a magnetic field detecting element mounted on the element guide so that the interlinking surface is vertical and perpendicular to the moving direction is provided, and the magnetic field detecting element is moved in a direction orthogonal to the magnetic field detecting element guide. Thus, the position where the magnetic field intensity becomes a zero value is measured.

However, in this method and apparatus for measuring horizontal displacement of a tunnel machine, even if the transmitting coil and the receiving coil are not exactly orthogonal, there is a position where a zero value is obtained, so that a measurement error is likely to occur. In addition, it is possible to detect only the horizontal direction, that is, only the position on the pipe axis of the underground pipe, and it is not possible to detect the direction in which the pipe is buried from arbitrary measurement values. If you are going to perform the construction without excavation, it is not possible to determine in which direction to excavate from the construction start position, and the transmission surface of the transmission coil is adjusted so that its central magnetic field is orthogonal to the observation point Therefore, there is a problem in that it requires labor and causes an error. The present invention has been made in order to solve the above-mentioned conventional problems, and it is possible to accurately detect the position of an underground detection object from an arbitrary position on the ground and efficiently without requiring much labor. It is an object of the present invention to provide a position detection method capable of detecting a position.

[0006]

According to the present invention for solving the above-mentioned problems, an electric signal is supplied to a magnetic field generating means arranged on an object to be detected, and a magnetic field generated by the magnetic field generating means is arranged at an observation point. What is claimed is: 1. A position detecting method comprising: detecting a position of an object to be detected from an output signal of the magnetic detection element by using a magnetic detection element, wherein the magnetic field generation unit is a cross-shaped coil including two transmission coils; Using a plurality of magnetic sensing elements aligned on the same plane, a signal which is AM-modulated by a signal wave having a carrier wave having the same phase shifted by 90 ° is transmitted to two transmission coils of the cross-shaped coil. Then, a magnetic field generated from the cross-shaped coil is detected by the plurality of magnetic detection elements, and a signal generated in the magnetic detection element and a carrier wave to the transmission coil are synchronously detected. Comparing the signal after synchronous detection is detected by the magnetic detecting element of the phase, and then by correcting the alignment direction of the magnetic detection element so that this phase is matched,
The position of the detected object is detected.

[0007]

According to the present invention, a sine-modulated wave and a cosine-modulated wave are transmitted from an orthogonal cross-shaped transmitting coil such that the combined magnetic field becomes the same rotating magnetic field as when one coil is rotating. Signals generated in a plurality of magnetic detection devices are subjected to synchronous detection with a carrier to a transmission coil, and a signal corresponding to the relative position between the transmission coil and each magnetic detection element and the phase of the signal wave is obtained. Then, by comparing the phases of the signals after synchronous detection detected by the individual magnetic detection elements, the center position of the transmission coil and the direction of the arrangement surface of the magnetic detection elements are uniquely determined.

Next, when a plurality of magnetic detecting elements on the same plane are rotated or translated so that the phases of the signals after synchronous detection detected from the plurality of magnetic detecting elements match, this operation is performed. The direction indicated by the alignment direction of the magnetic detection elements at the time of completion is the direction indicating the position of the transmission coil, and thereby the position of the transmission coil, particularly the direction in which the transmission coil is located from the observation point is detected, for example, the position of the buried pipe is Is detected.

[0009]

Embodiments of the present invention will be described below in detail with reference to the drawings. 1 to 3 show an embodiment of the present invention, and FIG. 1 is a diagram showing a system configuration of a position detecting device used for implementing a position detecting method according to the present invention. In the drawing, reference numeral 1 denotes a buried pipe as a detection object buried at a predetermined depth underground. Inside this buried pipe 1,
A movable carriage 2 running inside the buried pipe 1 is inserted. A wheel rotation sensor (not shown) for measuring a rotation amount of a wheel such as a rotary encoder is provided on the wheel 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 distance from the entrance of the movable carriage 2 in the buried pipe 1.

[0010] Transmission coils 6 and 7 as magnetic field generating means are attached to the mobile trolley 2.
Numeral 7 is formed in a cross shape on the same axis as the central axis C of the buried pipe 1 and orthogonal to the same point. The transmission coil 6 is supplied with a sin-modulated alternating current from a signal supply device 8 such as an oscillator via a power line 9, and a magnetic field is applied to the transmission coil 6 such that the central magnetic line Mc is orthogonal to the central magnetic line X in any phase. appear. The transmission coil 7 is also supplied with an alternating current that is similarly cos-modulated. In this case, for example, it is preferable to use several K to several hundred KHz (200 KHz in this embodiment) for the carrier wave and several hundred Hz (400 Hz in this embodiment) for the modulation wave.

On the other hand, a magnetic detection device 10 is movably arranged at an observation point on the ground. Magnetic detection device 10
Is provided so as to be rotatable about an axis parallel to the central axis C of the buried pipe 1 by a moving means 12 mounted on the base 11, and to be capable of being translated in a direction penetrating the plate surface of the buried pipe 1 at right angles. And a lower receiving coil 14 and an upper receiving coil 15 provided above and below the substrate 13. The lower receiving coil 14 and the upper receiving coil 15 have a function as a magnetic detecting element, and the lower receiving coil 14 and the upper receiving coil 15 have their magnetic detecting surfaces 14a and 15a on the same plane. In addition, in the case of the present embodiment, they are vertically arranged by being arranged on a plane parallel to the plate surface of the substrate 13.

Lower receiving coil 14 and upper receiving coil 15
Measures the magnetic field strength and sends the measurement signal to signal line 1
The signals are transmitted to the measuring devices 18 and 19 via the devices 6 and 17. The measuring devices 18 and 19 operate at the same frequency as the signals from the upper and lower receiving coils 14 and 15 and the signal from the signal supply device 8 supplied via the signal line 20, that is, the carrier to the transmitting coils 6 and 7. A certain reference signal is synchronously detected, and a signal corresponding to the phase of the signal wave is sent to a display 21 such as an oscilloscope via a signal line 22 and a signal line 22.
23.

Next, a position detecting method according to the present embodiment will be described. First, after inserting the movable trolley 2 to which the transmission coil 6 is attached inside the buried pipe 1, the magnetic detection surfaces 1 of the lower reception coil 14 and the upper reception coil 15 of the magnetic detection device 10 are arranged.
The mobile trolley 2 is moved so that the centers of the transmission coils 6 and 7 are located at the intersection of the plane orthogonal to the centers of 4a and 15a and the central axis C of the buried pipe 1.

A signal supply device 8 is connected to the transmission coil 6.
Supplies a sin-modulated AC current via a power line 9, and the transmission coil 7 is similarly supplied with a cosine-modulated AC current. In any phase, the center line of magnetic force M
c generates a magnetic field in a direction orthogonal to the central magnetic line of force X. Next, the magnetic field generated from the transmitting coil 6
Are detected on a plane orthogonal to the center of the magnetic detection surfaces 14a and 15a of the upper and lower receiving coils 14 and 15 arranged on the same surface toward
19, and are synchronously detected by the measuring devices 18 and 19 using the same reference signal of 200 KHz as the carrier wave to the transmission coils 6 and 7. The reception level (magnetic field strength) corresponding to the phase of the signal wave is signaled to the display 21. The power is transmitted via the wires 22 and 23.

At the time of position detection, the transmitting coil 6 is transmitted to the intersection of the center axis C of the buried tube 1 and the plane orthogonal to the center of the magnetic detection surfaces 14a, 15a of the lower receiving coil 14 and the upper receiving coil 15. The carriage 2 is moved so that the centers of the coils 6 and 7 are located. As shown in FIG. 2, the observation signal obtained in this manner is obtained as a 400 Hz sine wave when the reception level is plotted on the vertical axis and the time is plotted on the horizontal axis.

At this time, the observed signals obtained from the lower receiving coil 14 and the upper receiving coil 15 represent the relative positional relationship between the transmitting coils 6 and 7 as a phase difference as shown in FIG. The upper and lower receiving coils 14,
The direction of the fifteen alignment planes indicates the center of the transmitting coils 6 and 7. If the two signals detected by the upper and lower receiving coils 14 and 15 do not match, the control direction of the attitude of the upper and lower receiving coils 14 and 15 on the alignment plane is determined from the phase shift direction. Can be.

For example, as shown in FIG. 3A, when the phase of the lower receiving coil 14 is advanced, FIG.
As shown in (1), the upper receiving coil 15 is corrected to the upper side, or the lower receiving coil 14 is corrected to the lower side. Further, as shown in FIG. 3C, when the phase of the lower receiving coil 14 is delayed, the correction opposite to that of FIG.
5 can be corrected to the lower side, or the lower receiving coil 14 can be corrected to the upper side so as to match the two.

The direction of correction differs depending on the coil winding direction of the receiving coil. Further, there may be two or more receiving coils. In this way, by correcting the inclination (alignment direction) of the receiving coils 14 and 15 so that the phases match,
The positions of the transmitting coils 6 and 7 can be detected, and thereby the position of the buried pipe 1 that is the object to be detected can be detected.

[0019]

According to the position detecting method of the present invention, the transmission coil is a cross-shaped coil composed of two transmission coils, and carrier waves having the same phase from the signal supply device are respectively supplied to the cross-shaped coil for each of the two coils. A signal that is AM-modulated with a signal wave that is 90 ° out of phase is transmitted, and the magnetic field generated from the transmission coil is detected by a plurality of reception coils of a magnetic detection device arranged on the same surface toward the transmission coil. Then, the signal generated in the receiving coil and the carrier to the transmitting coil are synchronously detected, the phases of the signals detected by the plurality of receiving coils after the synchronous detection are compared, and the signals are received so that the phases match. Since the position of the object to be detected is detected by correcting the coil alignment direction, the position of the object to be detected in the ground can be accurately and efficiently detected from any position on the ground. That.

[Brief description of the drawings]

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

FIG. 2 is a block diagram of a signal processing system of FIG. 1;

FIG. 3 is an explanatory diagram for explaining a relationship between a relative position of a transmitting and receiving coil of FIG. 1 and an observation signal.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Buried pipe (detected object) 6 ... Transmission coil 7 ... Transmission coil 8 ... Signal supply device 10 ... Magnetic detection device 12 ... Moving means 14 ... Lower receiving coil (receiving coil) 15 ... Upper receiving coil (receiving coil)

Continuation of the front page (56) References JP-A-57-133373 (JP, A) JP-A-59-153112 (JP, A) JP-A-63-120219 (JP, A) JP-A-8-146146 (JP) , A) Special table Heisei 3-500212 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01V 3/08 G01B 7/00 G01R 33/02

Claims (1)

(57) [Claims] 1. 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 detected. A position detecting method for detecting the position of an object to be detected from a signal, wherein the magnetic field generating means is a cross-shaped coil composed of two transmitting coils, and a plurality of magnetic fields whose magnetic detecting surfaces are aligned on the same plane. A detection element is used to transmit an AM-modulated signal to each of the two transmission coils of the cross-shaped coil by a signal wave obtained by shifting a carrier wave having the same phase by 90 °, and to generate a plurality of magnetic fields generated from the cross-shaped coil. Detected by the plurality of magnetic detecting elements, synchronously detects a signal generated in the magnetic detecting element and a carrier to the transmitting coil, and detects a signal after the synchronous detection detected by the plurality of magnetic detecting elements. Of comparing the phases, then by correcting the alignment direction of the magnetic detection element so that this phase is matched, the position detecting method and detecting a position of the object detection object.