JPS625114A - Position detector of excavating machine - Google Patents

Abstract

PURPOSE:To detect accurately depth position of an excavating from the ground surface, by installing magnetic field detectors in 2 positions on the vertical line on the periphery of the machine and a lead wire along the excavation indicating line respectively. CONSTITUTION:A pair of magnetic field detectors 11 is installed on the vertical line of the periphery of an excavating machine 1 and a lead wire 12 along the both sides of an excavation indicating line T on the ground surface. An electric current is admitted into the lead wire 12 from the source 13, the magnetic field thus formed is detected by the detector 11 and its signal is introduced into a controller 14 for correction of depthwise excavating direction of the machine 1. Thus, continuous detection of position of the excavating machine can be attained rapidly and accurately.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a position detection device for an excavator that detects the position (depth) of the excavator from the ground surface when the excavator excavates underground.

[Background of the invention]

When a pipe, etc. is buried underground without excavation using a small-diameter excavation method, etc., an excavator placed at the tip of the pipe excavates underground along a predetermined excavation target line. ---It is necessary to move forward. For this reason, it is necessary to detect the position of the excavator underground and correct it if the excavator deviates from the excavation target line. In this way, detecting the position of the excavator is an essential means when excavating underground and burying a pipe. Hereinafter, conventional position detection means will be explained with reference to the drawings.

FIG. 4 is a sectional view of a conventional position detection device.

In the figure, 1- is an excavator excavating underground, 2 is a buried pipe provided at the rear of the excavator 1, and 3 is a starting shaft for the excavator 1 to start digging. A pushing device (not shown) for pushing the rear part of the buried pipe 2 is provided in the starting shaft 3. 4 is a laser oscillator installed at a proper location in the starting shaft 3. The laser oscillator 4 is configured to emit a laser beam 5 to the excavator 1 through the buried pipe 2. 6
is a screen provided in the excavator 1, which receives the laser beam 5 from the laser oscillator 4. T indicates the excavation target line of the excavator 1.

When the excavator 1 is excavating on the excavation target line T, the laser beam 5 is received at a predetermined location on the screen 6, but when the excavator l deviates from the excavation target line T, the laser beam 5 It also deviates from the predetermined location. By the deviation of the laser beam 5 on the screen 6, the deviation of the excavator 1 from the excavation target line T in the horizontal direction and the depth direction is detected, and the trajectory of the excavator 1 is thereby corrected.

However, the above method has the disadvantage that when the excavation target line T is curved (in the case of curved construction), the laser beam 5 does not reach the screen 6, so the position deviation of the excavation machine 1 cannot be detected. In addition, the excavator 1
And the diameter of the buried pipe 2 is small (for example, the diameter is about 100 m)
In this case, there was also a drawback that the passage of the laser beam 50 could not be secured by the various devices installed in the excavator 1 and the buried pipe 2. In order to eliminate such drawbacks, the following measures have been proposed.

FIG. 5 is a sectional view of another conventional position detection device. In the figure, the same parts as in FIG. 4 are given the same reference numerals. 7 is a magnetic field generator provided in the excavator 1, 8 is a magnetic field detector that detects the magnetic field generated by the magnetic field generator 7, 9 is a survey instrument that measures the position of the magnetic field detector 8 on the ground surface, and 10 is a surveying device. This is a control unit that inputs the position signal of the magnetic field detector 8 from the device 9 and controls the excavation direction of the excavator 1 based on this.

When the N and S poles of the magnetic field generator 7 are on a vertical line,
On the earth's surface, the vertical magnetic field strength is maximum (or the horizontal magnetic field strength is minimum) at a point directly above the magnetic field generator. Therefore, the magnetic field detector 8 is moved (scanned) on the earth's surface.
If the point where the magnetic field intensity is maximum (or minimum) is searched, that point will be the point directly above the magnetic field generator 7. Then, if the position of the magnetic field detector 8 is measured by the surveying device 9, the excavator 1
can detect the position of

By the way, when a small-diameter pipe is buried underground using a small-diameter excavation method or the like, there are cases in which strict limitations are placed on the depth at which the pipe is buried, depending on the surrounding conditions such as other buried objects. Therefore, when such limiting conditions are imposed, it is necessary to accurately manage the depth from the ground surface to the excavator 1. However, with the above position detection device, it is impossible to accurately detect the depth of the excavator 1. At present, no device has been proposed that accurately detects the position of such an excavator 1 in the depth direction.

[Purpose of the invention]

The present invention has been made in view of the above circumstances, and its purpose is to provide a position detection device for an excavator that can accurately detect the position of an excavator in the depth direction from the ground surface. There is K.

[Summary of the invention]

In order to achieve the above object, the present invention is provided with a set of magnetic field detection devices at two locations above and below in the direction of underground depth around the circumference of the excavator, and arranged along the excavation target line of the excavator. The present invention is characterized in that a current is supplied to the conducting wire, and the magnetic field generated thereby is detected by the magnetic field detection device.

[Embodiments of the invention]

Hereinafter, the present invention will be explained based on illustrated embodiments.

FIG. 1(a) is a plan view of a position detection device according to an embodiment of the present invention, FIG. 1(b) is a sectional view along the excavation target line shown in FIG. 1(a), and FIG. 1(C) is a sectional view taken along line CC in FIG. 1(a). In the figure, the same parts as those shown in FIG. 4 are given the same reference numerals. lla and llb are magnetic field detectors that are provided above and below in the depth direction of the excavator 1 to detect magnetic fields. 12 is a guide line laid along both sides of the excavation target line T on the ground surface), and the distance from the excavation target line T to the guide @12 on one side and the distance to the guide line 12 on the other side is be made equal. This guide wire 12 is composed of one continuous conducting wire. A power supply 13 is connected to both ends of the guide wire 120, and supplies alternating current to the guide wire 12. Reference numeral 14 denotes a controller that receives signals from the magnetic field detectors 11a and 11b and performs necessary calculations and controls.

Next, the operation of this embodiment will be explained with reference to the position of the shield tunneling machine shown in FIG. 2 and the magnetic field strength characteristic diagram shown in FIG. 3. When a current is supplied from the power source 13 to the guide wire 12, a magnetic field is formed around the guide wire 12, and this magnetic field is detected by the magnetic field detector 11a.

11b. Here, E: Electrical current supplied from the power source 13 to the induction wire 12. : Amplitude of electric current ω: Angular frequency of current I Hy: Magnetic field strength y of Y-axis (described later) direction component: Guide wire 1
2 and the magnetic field detectors 11a and llb: distance in the Y-axis (described later) direction W: distance between the excavation target line T and the guide line 12,
The current I and the magnetic field strength Hy are expressed by the following equation.

I=I. sinωt ・・・・・・・・・・・・・・・
・・・・・・・・・・・・・・・・・・・・・(1) FIG. 2(a) is a diagram showing a state in which the shield excavator 1 is at a position deviated from the excavation target line T. , and the guiding line 12 on the ground surface is
．． 12 is taken as the Y-axis, and a line perpendicularly drawn from the excavation target line T is taken as the Y-axis.

In addition, the center F of the shield tunneling machine l and each magnetic field detector 11a
, llb is denoted by r.

Furthermore, the excavation locus that the excavator 1 should travel is in the direction perpendicular to the plane of the paper at the coordinates (0, ye).

In this case, the excavator 1 shown in FIG. 2 is at a position shifted by δ in the X-axis direction (horizontal direction) and δa in the Y-axis direction (depth direction). Magnetic field detector 1 in this embodiment
1a and llb are for detecting the deviation (deviation) δa in the Y-axis direction, and by this detection, the excavator 1 is controlled in the direction in which the deviation δa becomes O. In addition, the deviation δ
The detection means is detected by other means, but since this detection means has been separately filed by the present applicant, its explanation will be omitted.

Now, the position of the excavator l shown in Fig. 2 is X=δX...
・・・・・・・・・・・・・・・・・・・・・・・・
・・・・・・・・・・・・(3) y = 7*+δy・・
··········river··············
...(41), so the above equation (2) becomes as follows.

・・・・・・・・・(5) Now, considering the actual conditions, δ < W,
＆y＜7＠ ・・・・・・・・・・・・・・・・・・
......(6). In each of the above formulas, the value 7j
The actual values of , W - δ, and δ are y, = 2
00 α, W = 100 va, δ engineering = 151 δy = 15
It is about am.

If these values are used in equation ()), and if these values are considered to be sufficiently smaller than 1 and ignored, the following approximate equation is obtained, although the accuracy is slightly lowered.

FIG. 3 is a magnetic field strength characteristic diagram based on (9) 2, in which the horizontal axis represents the depth y, and the vertical axis represents the magnetic field strength H. In the figure, the target excavation depth y and the magnetic field strength in the vicinity are shown, and it can be seen that near the actual excavation conditions, the magnetic field strength HyFi changes almost linearly with respect to the depth y. Here, Hya: magnetic field strength Hyb detected by the magnetic field detector 11a
: Magnetic field strength δa detected by the magnetic field detector 11b : Deviation (deviation) from the target excavation depth y of the excavator 1. Equation (9) is expressed by the following equation.

H=ni+(t-km・δy)・・・・・・・・・・・・
......The coordinates (0, ys) of α1 excavation target depth should be at the center of the excavator 1, and the magnetic field detector 11a
, llb are provided at a distance r vertically from the center of the excavator 1, so each magnetic field detector 11a.

The magnetic field strengths Hya and Hyb detected at 11b are Hy
, L=kI (to 1-! (δy+r))...
・・・・・・・・・・aTJHyb=＋ (1−nibaδyr))・・・・・・・・・・・・・・・・・・(+
It becomes 2. Since the electrical signal Eya output from the magnetic field detector 11a and the electrical signal Eyb output from the magnetic field detector ilb are proportional to the respective detected magnetic field strengths, the following equation holds true.

gya=lcB-k+ (1, km (δy+r))・
・・・・・・・・・・・・(13Eyb=km'+ (
1k-(δy-r))・・・・・・・・・α4In the above equations, k is a proportionality constant, and this proportionality constant kJ is , 11b, the number of turns of the coil is N, and the cross-sectional area of the coil is a, then ka
=N-a・ω.

From the above, the positional deviation δa of excavator 1 is given by: where stone is a coefficient, yak, mai□ ・・・・・・・・・・・・・・・・・・・・・
・・・・・・・・・ aey, Mayuzumi + W is lazy. In the formula 0!9, the distance r is a more determined value for the excavator, and the coefficient 4 is constant because the depth y6 and the distance W are determined values. Therefore, the positional deviation δa of the excavator 1 is detected by the magnetic field detector 11a.

It is determined by detecting the signals Eya and Eyb of 11b. Here, it is noteworthy that the coefficients , , , , are not included in the (US formula).In other words, as is clear from the above formula, these coefficients are It is related to the conditions of the coils 11a and 11b, etc., and for example, if there is a fluctuation in the current supplied to the guide wire 12, it can be seen from the formula <13.fi4). The signals Eya and Eyb fluctuate as follows. But a! As is clear from Equation 9, Ic and positional deviation ay are determined by these signals E
Since it is obtained by calculating the ratio of ya and Eyb, the above fluctuations are canceled, and in the end, no error occurs in the position deviation δyK even due to fluctuations in various conditions, making it impossible to obtain an accurate value. can.

In this embodiment, the magnetic field detector 11a is used as described above.

The signal obtained in step 11b is used to detect the depth position deviation δa. That is, the controller 14 is connected to the magnetic field detector 11
The signals Eya and Eyb of a and llb are input, and based on these values, the calculation of the above-mentioned inclination formula is executed to calculate the positional deviation δa. Then, control is performed to correct the excavation direction of the excavator 1 according to the calculated value δ.

5. In this embodiment, guide wires are laid along the excavation target line at equal intervals on both sides, and alternating current is supplied to the guide wires, so that the magnetic field generated in the guide wires is It is detected by two magnetic field detectors installed above and below in the depth direction.
Therefore, based on these detected values, the position of the excavator in the depth direction from the ground surface can be rapidly and accurately continuously detected.

In addition, in the description of the above embodiment, an example in which the guide wire is laid on the ground surface has been described, but the guide wire may be buried in the ground. Furthermore, when the distance between the guide wires on both sides is large or when the guide wires are used with one end grounded, the guide wires can be laid so as to coincide with the excavation target line. Furthermore, it is clear that the present invention is applicable even if the excavation is a curved excavation.

〔Effect of the invention〕

As described above, in the button 1 of the present invention, an excavator is provided with a set of upper and lower magnetic field detection devices, and a conducting wire is laid along the excavation target line, and the magnetic field generated by K is supplied with current to this conducting wire. is detected by the magnetic field detection device, so the position of the excavator in the depth direction from the ground surface can be detected rapidly, accurately, and continuously.

[Brief explanation of drawings]

FIGS. 1(a), (b), and (c) are a plan view and a sectional view of a position detection device according to an embodiment of the present invention, FIG. 2 is a sectional view showing the position of an excavator, and FIG. 3 is a magnetic field The intensity characteristic diagrams, FIGS. 4 and 5, are cross-sectional views of a conventional position detection device. 1...Encavator, lla, llb...Magnetic field detector, 12...Guiding wire, 13...
Source, 14...controller, T...excavation target line. Figure 1 (a) Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] An excavator that excavates underground, a set of magnetic field detection devices provided at two locations above and below the circumference of the excavator in the underground depth direction, and a set of magnetic field detection devices arranged along the excavation target line of the excavator. A position detection device for an excavator, comprising a conductor and a power source that supplies current to the conductor.