JP2993634B2 - Precise detection method of underground excavator position - 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 and an apparatus for precisely detecting the position of an underground excavator (hereinafter, sometimes referred to as an excavator), and particularly to the position of an underground excavator suspended from the ground surface and excavated vertically. The present invention relates to a precise detection method and device.

[0002]

2. Description of the Related Art FIGS. 1 (A) and 2 (A) show a method of detecting the position of a down swing type underground excavator proposed by the present applicant in Japanese Patent Application No. 6-289490. The underground excavator 1 is suspended in the direction of gravity from a suspension unit 4 on the ground surface 3 by a suspension wire 5 connected to the top surface 2 thereof, and excavates a vertical hole 8 vertically. In practice, the tip of the excavator 1 may be displaced from the vertical direction due to the hardness of the stratum, and the verticality of the pit 8 may be impaired. To ensure verticality, detect the positions of the two reference points 17 provided on the excavator 1, calculate the excavator posture from those positions, and correct the required posture or position of the excavator 1. Has been done. FIGS. 2A and 4 show a method for measuring the position of one of the two points, and the same measurement can be performed for the other point. The weight 9 is measured by the suspension unit 4 from the reference point 7 on the ground surface 3 to the measuring wire 6.
Hang by. A position detection unit 20 is provided at each reference point 17 for detecting the position of the weight 9 with respect to the top surface 2 of the excavator 1. If the coordinates of the two reference points 17 on the excavator 1 with respect to the two reference points 7 on the ground 3 are measured, the attitude of the excavator 1 can be calculated. For example, the computer 34 shown in FIG. The result can be displayed on the display unit 36.

FIGS. 2 (A) and 2 (C) show position detection by arranging nine approach sensing elements 11 made of Hall elements in a C-shaped and third column of FIG. 4 at an interval of, for example, 10 cm. Unit 20
An example in which the weight 9 is provided with a magnet 10 is shown. Consider a case where the weight 9 is located between the B and C rows in the second column of FIG. Since the output of the Hall element is proportional to the magnetic field, it increases as the distance between the magnet 10 and the Hall element decreases, and the output of the Hall element closest to the magnet becomes the largest. FIG. 4B shows the output distribution of the approach detection element 11 on the straight line in the third column.
(C) shows the distribution of the output of the approach detection element 11 on the straight line in row C. FIG. 4D shows a curve obtained by connecting the output values of the proximity detection elements of FIG. 4B by interpolation, and similarly forms a curve obtained by connecting the output values of the proximity detection elements of FIG. 4C by interpolation. The principle of measuring the coordinates of the weight 9 with respect to the excavator 1 as an intersection of a straight line passing through the peak value of the curve and parallel to the row and the column is shown. If the coordinates of the weight 9 with respect to the excavator 1 are measured, the position of the excavator 1 with respect to the reference point 7 on the ground surface 3 can be detected as described above. FIG. 2B shows a position detection unit 20 in which 25 proximity sensing elements 11 are arranged in a matrix, and the operation is the same as that of FIG. 2A.

In FIG. 3 showing an example of the configuration of the position detection unit 20, a multiplexer 22 sequentially applies a current I of a control current generator 30 to each proximity sensing element 11, and outputs an output voltage Eh via an amplifier 25 to a level. This is given to the detection unit 26.
The multiplexer control unit 32 sequentially switches the connection of the control current I and the output voltage Eh to each proximity sensing element 11 by switching the multiplexer 22. The determination unit 28 is a level detection unit
Based on the voltage from 26 and the position of the proximity sensing element 11 at which the voltage was generated from the location memory 29, a plurality of proximity sensing elements
The position of the magnet 10 facing 11 is determined. The computer 34 determines the position of the excavator 1 based on the coordinates of the reference point 7 on the ground surface 3, the coordinates of the plurality of proximity sensing elements 11 on the excavator 1, and the position of the magnet 10 with respect to the proximity sensing element 11 from the position detection unit 20. Calculate surface coordinates. The calculation result is provided for display on the display unit 36 or recording by the recording unit 38.

[0005]

However, the position detection method of the underground excavator proposed above has the following problems. (1) Since the outputs of the plurality of proximity sensing elements 11 are used as measured values as they are, errors occur due to variations in the characteristics of the proximity sensing elements 11. (2) When the temperature of the air or the stable liquid in the pit after excavation fluctuates, an error occurs due to a temperature change in the output of the proximity sensing element 11. (3) When the proximity sensing element 11 includes a magnetic material for its original function or to improve sensitivity, when the magnet 10 attached to the weight 9 repeatedly approaches and separates from a strong magnetic field, residual magnetism is generated in the magnetic material. It remains and causes an error.

Accordingly, an object of the present invention is to provide a method and an apparatus for accurately detecting the position of an underground excavator in which the influence of variations in the characteristics of the approach sensing element is suppressed.

[0007]

According to the position determination method shown in FIG. 4, the present inventor determines the position of the weight 9 as a point directly determined by the coordinate values on two coordinate axes obtained from the outputs of the plurality of proximity sensing elements 11. Therefore, attention was paid to the point that the influence of the variation in the characteristics between the proximity sensing elements 11 is likely to occur. Weight 9
If the position is obtained as an average value of the outputs of the plurality of proximity sensing elements 11 by some method, the influence of the variation in the characteristics of the elements 11 can be suppressed.

Referring to the embodiment of FIG. 1, according to the method for accurately detecting the position of an underground excavator according to the present invention, the method of detecting the position of an underground excavator 1 suspended from the ground surface 3 and excavating vertically. , One or more fixed reference points 17 are provided on the excavator top surface 2, and three line segments α, β, γ intersecting each other at 120 degrees at each reference point 17 are determined on the top surface 2, 9, a plurality of approach sensing elements 11 that output according to the distance to each line segment α,
fixed on β and γ at a fixed interval (hereinafter, also referred to as a star arrangement), from the reference point 7 on the ground surface 3 to just above the corresponding reference point 17 on the underground excavator 1, the weight having a smaller diameter than the fixed interval The weight 9 is suspended, and points Pa, Pb, and Pc (see FIG. 5) where the outputs are maximum on each of the three line segments α, β, and γ are determined from the distribution of the output of the proximity sensing element 11 in each of the three line segments. , The perpendiculars La, Lb, at the point of maximum output for the three line segments on the top surface 2
Center of gravity 33 of triangular region 31 (see FIG. 5) surrounded by Lc (see FIG. 5)
(See FIG. 5), this is defined as the vertical projection position of the weight 9, and the coordinates of the reference point 17 of the excavator 1 with respect to the ground reference point 7 are determined based on the coordinates of the center of gravity 33 with respect to the reference point 17.

Preferably, the temperature change characteristics of the output of each of the plurality of approach sensing elements 11 are measured and stored in advance, and a thermometer 23 (see FIG. 6) is provided near the approach sensing elements 11, and an underground excavator is provided. The output of each approach detection element 11 at the time of detecting the position 1 is corrected by the temperature measured by the thermometer 23 at the time of the detection and the stored temperature change characteristic. More preferably, a magnet 10 is attached to the weight 9, and each of the proximity sensing elements 11 includes a magnetic body (not shown) whose magnetization intensity increases or decreases according to the approach / separation of the magnet 10, and a certain number of underground excavations After detecting the position of the machine 1, the residual magnetism of the magnetic material of each sensing element 11 is demagnetized.

[0010]

The operation of the present invention will be described with reference to FIG. In this example, the approach sensing element 11 is a hall element, and the plurality of approach sensing elements 11 are fixed in a star arrangement on three line segments α, β, and γ intersecting at 120 ° at a reference point 17 on the excavator 1. Then, the two weights 9 each having the magnet 10 are suspended from the suspension unit 4 provided with the two reference positions 7A and 7B, but the present invention is not limited to this example.

Since the weight 9 suspended from the reference point 7 on the ground surface 3 to just above the reference point 17 on the underground excavator 1 is vertically below the reference point 7, the plane coordinates of the reference point 7 on the ground surface are determined by this weight. 9 are also maintained in plane coordinates parallel to the ground surface. The weight 9 is 1 upward from the reference point 17 in the line segment β in FIG.
It is assumed that the second and third proximity sensing elements 11 substantially touch the top surface 2 slightly to the right of the line segment β. In this case, it is assumed that the output of the proximity sensing element 11 in the star arrangement is as shown in FIG. FIG. 5B is a diagram in which the line segments α, β, and γ are respectively retracted from the center point S of the star arrangement by the same distance in parallel with the position of FIG.
Black circles separated from the respective line segments α, β, γ in a direction perpendicular to each other represent the output of each proximity sensing element 11, and the size of the distance from the line segment is proportional to the magnitude of the output of each proximity sensing element 11. The continuous distribution of the output of the proximity sensing element 11 can be estimated by connecting the black circles for the line segments α, β, and γ with a smooth curve. However, the position of the black circle is not an estimated value but an actually measured value. From this distribution, the position where the output of the proximity sensing element 11 is maximum in each line segment, that is, the point closest to the weight 9 on the line segment can be determined as the peak points Pa, Pb, and Pc.
Line segments α, β, γ at peak points Pa, Pb, Pc on top surface 2
Perpendiculars La, Lb, and Lc to define a triangular area 31.

Now, assuming that the approach sensing element 11 is an ideal sensor and has no error or variation, the perpendiculars La, Lb, and Lc intersect at one point, and that point becomes the vertical projection position of the weight 9. . However, since the actual approach sensing element 11 has errors and variations, the three perpendicular lines La, Lb, and Lc do not intersect at one point and define a triangular area 31. In the prior art of FIG.
Since only two coordinates are used, the vertical projection position of the weight 9 is determined as the intersection of a straight line passing through the peak value of the interpolation curve. For this reason, in the case of FIG. 4, since the intersection of the two straight lines including the error and the variation of the approach sensing element 11 is used as the vertical projection position of the weight 9, no compensation for these errors and variations is made, and Errors and variations directly affect the measurement.

On the other hand, in the present invention, the center of gravity of the triangular region 31 is described.
33 is obtained and set as the vertical projection position of the weight 9. This center of gravity
Obtaining 33 means that errors and variations of the plurality of approach sensing elements 11 are averaged to suppress the influence. Therefore,
High-accuracy measurement with less influence of these errors and variations becomes possible.

In this manner, the object of the present invention is to provide "a method and an apparatus for accurately detecting the position of an underground excavator in which the influence of variations in the characteristics of the proximity sensing element is suppressed."

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the embodiment of FIG. 1, the arrangement of the plurality of proximity sensing elements 11 is not the matrix type of FIG. 2 (B) but the star type of FIG. 2 (D). The failure rate can be reduced and the cost can be reduced. In addition, the measurement accuracy at the corners of the position detection unit 20 can be maintained higher than in the case of the cross type shown in FIG.

The temperature change of the output of the position detecting element 11
This is not a serious problem when used in a constant temperature environment, but when the temperature of the measurement environment changes significantly, for example, the approach of the support 21 of the approach sensing element 11 in FIG. It is desirable to provide a thermometer 23 in the vicinity of the sensing element 11 to compensate for a temperature change using a temperature-output voltage characteristic created in advance at a factory. More specifically, the following method can be used for the proximity sensing element 11 composed of a Hall element.

(A) Measurement is performed in a temperature change test environment such as in a thermostat, and an output voltage-temperature characteristic curve for each Hall element is created as shown in FIG. This is stored. (b) At the start of measurement in the field, the output voltage of each Hall element is measured as the initial Hall element voltage in the absence of a magnetic field.
(Calibration) (c) The initial Hall element voltages of the plurality of Hall elements are stored in the computer together with the temperature at the time of measurement (for example, 20 ° C.) as an initial Hall element voltage table as shown in the following table.

[0018]

[Table 1] Hall element output initial value when there is no weight (magnet) Hall element number Output voltage (volt) 10 ゜ C 20 ゜ C 30 ゜ C 1 4.0 4.5 5.0 2 4.1 4.0 4.9 3 4.2 4.5 5.3 ・ ・ ・n………

(D) The weight 9 with the magnet 10 is suspended and the main measurement is started. (e) If there is a temperature change during measurement (for example, from 20 ° C to 18 ° C), the output voltage-temperature characteristic curve indicates that the Hall element No. 1
To No. n, the difference between the voltage at 20 ° C. and the voltage at 18 ° C. is obtained, and the obtained difference is added to the Hall element voltage currently being measured and corrected. In this way, it is possible to compensate for variations in temperature characteristics due to differences in Hall elements.

In the case where the magnet 10 attached to the weight 9 has a strong magnetic field and the proximity sensing element 11 includes a magnetic material for its original function or to improve the sensitivity, the approach of the weight 9 to these elements 11 is considered. When the separation is repeated, residual magnetism remains in the magnetic material, causing an error. In order to avoid this error, for example, as shown in FIG. 7, near the proximity sensing element 11 attached to the substrate 41 in the pressure vessel 40 which is a part of the position detection unit 20,
A degaussing head 44 energized by the degaussing circuit 43 may be provided. In the figure, reference numeral 42 indicates a top plate of the pressure vessel 40, and reference numeral 45 indicates a terminal for connecting each element 11 to the control cable 19.
If the display unit 36 (FIG. 3) detects an abnormality such as an abnormal change in the output of the proximity sensing element 11 or periodically performs degaussing by the degaussing head 44, the error due to the residual magnetism can be avoided. Can be.

[0021]

As described above, the method and the apparatus for accurately detecting the position of an underground excavator according to the present invention provide an approach sensing element on a line segment intersecting with each other at an angle of 120 °. The following remarkable effects are achieved because the variation in the characteristics of each unit is compensated. (B) The position of the underground excavator can be accurately detected with a device having a simple structure. (B) Use of a star arrangement enables precise detection with a small number of proximity sensing elements. (C) The number of proximity sensing elements can be reduced, and the failure rate of the entire apparatus can be reduced. (D) It is possible to compensate for variations in the temperature fluctuation of the output of the proximity sensing element. (E) If necessary, it is possible to demagnetize the residual magnetism of the magnetic components such as the proximity sensing element.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of one embodiment of the present invention.

FIG. 2 is an explanatory diagram of various arrangements of approach detection elements.

FIG. 3 is a block diagram of a position detection unit.

FIG. 4 is an explanatory diagram of an output of a proximity sensing element in a cross arrangement.

FIG. 5 is a table illustrating a method of interpolating the output of the proximity sensing element according to the present invention.

FIG. 6 is an explanatory diagram of a position detection unit provided with a thermometer.

FIG. 7 is an explanatory diagram of a position detection unit provided with demagnetizing means.

[Explanation of symbols]

 Reference Signs List 1 underground excavator 2 top surface 3 ground surface 4 hanging unit 5 hanging wire 6 measuring wire 7 reference point 8 vertical hole 9 weight 10 magnet 11 approach sensing element 15 depth sensor 17 reference point 19 control cable 20 position detecting unit 21 Support base 22 Multiplexer 23 Thermometer 24 Controller 25 Amplifier 26 Level detector 28 Discriminator 29 Position memory 30 Control current generator 31 Triangle area 32 Multiplexer controller 33 Center of gravity 34 Computer 36 Display 38 Recording unit 40 Pressure vessel 41 Substrate 42 Top Plate 43 Degaussing circuit 44 Degaussing head 45 Terminal.

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Tatsuyuki Ochi Kashima Construction Co., Ltd. 1-2-7 Moto-Akasaka, Minato-ku, Tokyo (56) References JP-A-6-94463 (JP, A) JP Hei 8-144571 (JP, A) JP-A-64-68613 (JP, A) JP-A-61-53513 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G01C 15 / 00-15/14 G01C 9/00-9/36 G01B 7/00 G01B 21/00 G01D 5/12

Claims (8)

(57) [Claims] 1. A method for detecting the position of an underground excavator suspended from the surface of a ground and excavating vertically, comprising:
More than one fixed reference point, and each reference point
Three line segments that intersect at 0 degrees are defined on the top surface, and a plurality of approach sensing elements that output an output according to the distance to the adjacent weight are fixed on each of the line segments at regular intervals, and a reference point on the ground surface , A weight having a smaller diameter than the constant interval is suspended from above to the corresponding reference point on the underground excavator, and the output on each line is obtained from the distribution of the output of the approach sensing element in each of the three lines. A maximum point is determined, a center of gravity of a triangular area surrounded by a perpendicular line at the point of maximum output with respect to three line segments on the top surface is defined as a vertical projection position of the weight, and the center of gravity with respect to the reference point is determined. A method for accurately detecting the position of an underground excavator, wherein the coordinates of the reference point of the excavator with respect to the ground reference point are determined based on the coordinates of the position. 2. The underground excavation method according to claim 1, wherein a temperature change characteristic of an output of each of the plurality of proximity sensing elements is measured and stored in advance, and a thermometer is provided near the proximity sensing elements. A method for accurately detecting the position of an underground excavator, wherein the output of each approach detection element at the time of detecting the position of the excavator is corrected by the temperature measured by the thermometer and the stored temperature change characteristic at the time of the detection. 3. The precision detection method according to claim 1, wherein a magnet is attached to the weight, and each of the proximity sensing elements includes a magnetic body whose magnetization intensity increases or decreases according to the approach / separation of the magnet. And a method for accurately detecting the position of an underground excavator, wherein the residual magnetism of the magnetic material of each of the sensing elements is demagnetized after a predetermined number of times of detecting the position of the underground excavator. 4. The precision detection method according to claim 1, further comprising a depth sensor for detecting a depth of the weight at a reference point on the ground surface, wherein a three-dimensional position of the excavator with respect to the ground reference point is provided. Precise detection method of underground excavator position by detecting. 5. The precision detection method according to claim 4, wherein two reference points are provided on the top surface of the excavator at a constant interval, and three line segments that intersect each other at 120 degrees at each reference point. A plurality of approach sensing elements, which are determined on the top surface and output according to the distance to the proximity weight, are fixed at a constant interval on each of the line segments, and the two reference positions spaced at the constant interval on the ground surface from the two reference positions. Each of the weights is suspended, and an output from the approach sensing element on three lines at a reference point corresponding to each of the weights and an output of the depth sensor corresponding to each of the weights are detected, and the detected proximity sensing is detected. A method for accurately detecting the position of an underground excavator by detecting the position and attitude of the excavator by detecting the three-dimensional position of each reference point corresponding to the reference point on each area from the outputs of an element and a depth sensor. 6. The method of claim 1, 2, 3, 4, or 5, wherein the proximity sensing element is a hall element, and the weight is provided with a magnet to accurately detect the position of the underground excavator. 7. The precision detection method according to claim 1, wherein said proximity sensing element is a magnetoresistive element,
An accurate method for detecting the position of an underground excavator, wherein the weight is provided with a magnet. 8. An apparatus for detecting the position of an underground excavator with respect to a ground reference point, said apparatus comprising three lines on said top surface intersecting at a predetermined reference point on said top surface at 120 degrees with each other. A plurality of approach sensing elements fixed at regular intervals and generating an output according to the distance to the adjacent weight; a weight having a diameter smaller than the constant interval; the underground excavator removing the weight from a predetermined position on the ground surface A suspension unit for suspending the unit immediately above the unit; and a distribution of the output of the proximity sensing element in each of the three line segments, the point where the output is maximum on each line segment, and three lines on the top surface. The position of the center of gravity of the triangular area surrounded by the perpendicular line at the point of maximum output with respect to the minute is determined as the vertical projection position of the weight, and a position detection unit that detects the position of the center of gravity with respect to the reference point is provided. Of the center of gravity An underground excavator position precise detection device that determines coordinates of the reference point of the excavator with respect to the ground reference point based on the coordinates.