JP6970079B2 - Ground penetrating radar - Google Patents

Description

The present invention is to prevent the underground buried objects such as water pipes, gas pipes, and communication cables buried in the ground from being caught and damaged while excavating the road surface by an excavating machine such as a backhoe. The present invention relates to an underground radar exploration device that can be suitably carried out.

In recent years, during construction using excavators such as power shovels and backhoes, underground objects such as telephone lines, power cables, optical cables, gas pipes, water pipes, and sewage pipes buried in the ground during excavation have been damaged. There is a damage accident. Such a damage accident causes serious damage to the inhabitants near the accident site.

There are roughly two conventional methods for dealing with damage to underground buried objects. The first method is the use of buried drawings. The buried drawing is a drawing showing the positions of cables, pipes, etc. buried underground. Using this drawing, the worker performing the construction estimates the position of the buried object in advance, and the excavation work is performed by the excavation machine while being careful not to damage the estimated underground buried object. The second method is a preliminary survey using a ground penetrating radar. This is to search for underground buried objects from the ground surface in advance by using a ground penetrating radar probe and an electromagnetic induction probe.

However, in the first method, when using the buried drawing, if it is buried in recent years, it can be avoided to some extent, but in the case of old buried objects for which no drawing remains or construction work on the site, etc. I have to rely on exploration. Further, in the second method, even in the survey by the ground penetrating radar, the ground penetrating radar cannot be frequently used because the accuracy is high but the cost required for the exploration is high. The survey by the electromagnetic induction spacecraft can estimate the position itself, but its accuracy is insufficient. In addition, even though the position can be estimated, a damage accident may occur due to carelessness of the operator or an operation error. Therefore, the following ground penetrating radar has been known as a technique for performing construction more safely.

There are various exploration methods such as elastic wave exploration, surface wave exploration, electrical exploration, ultrasonic exploration, and magnetic exploration as conventional techniques for underground exploration, but all of these exploration methods are large buried objects. Since the exploration resolution is low, it is difficult to reliably detect small buried objects such as buried pipes and communication cables in the ground by exploration. Of these, the magnetic exploration method is the only one that can be used for exploration of objects made of magnetic materials such as metals in the ground, as described in Patent Document 1, for example, but the burial depth and burial position are accurate. Judgment is difficult.

In addition, since the operator, also called the operator who operates the excavation machine, is not an experienced radar exploration person, it is not possible to read the radar screen while excavating and judge the existence of the buried object. Therefore, in order to perform excavation while monitoring the buried object, a separate radar exploration operator is required in addition to the operator of the excavation machine. Moreover, when the excavation depth becomes deep, it becomes necessary for the operator to enter the excavation range and repeat radar exploration, and such work is highly dangerous and unrealistic.

Still another prior art is a borehole radar exploration method, as described in Patent Document 2. It is possible to insert a cylindrical radar antenna into the boring hole and search up to the excavation depth of the boring hole, but for the boring hole excavated in the vertical direction, the underground buried object on the side It is for exploration and cannot be explored in the direction perpendicular to the excavation surface. In the first place, at the time of boring excavation, there is a risk of damaging underground buried objects by excavated parts such as screw augers, so such a method cannot be adopted.

Japanese Unexamined Patent Publication No. 2004-347533 Japanese Patent No. 5568237

Therefore, an object of the present invention is to provide an underground radar exploration device capable of easily and surely teaching an operator of an excavation machine an underground buried object existing in a target area.

Paragraphs and drawing numbers in parentheses () below indicate where the specification and drawings are written.
The present invention
a. An excavator main body 3 provided with an operating device 2 operated by an operator and capable of traveling in response to the operation of the operating device 2, and an excavator main body 3 provided in the excavator main body 3 and moving in response to the operation of the operating device 2. An underground radar exploration device provided in an excavator 1 including a possible excavator 4.
b The excavation section 4 is
A pair of side walls 12a and 12b extending along a plane perpendicular to the horizontal tilt center axis L1 and
A back wall 13 having a C-shaped cross section perpendicular to the tilt center axis L1 between the side walls 12a and 12b.
A flat bottom plate portion 14 extending from the back wall 13 to the opening side (diagonally lower left in FIG. 6 and left in FIG. 7) and to which a plurality of claw members 15 are fixed to the opening side edge portion.
It is a bucket that constitutes a storage space for accommodating excavated soil.
The parallelogram links (10a to 10d, 11a to 11d) provided at the tip of the boom 9 extending from the excavator main body 3 allow the portion of the back wall 13 opposite to the bottom plate portion 14 (upper portion of FIG. 6). It is connected so that it can be tilted with respect to the tilt center axis L1.
The boom 9 and the parallelogram links (10a to 10d, 11a to 11d) are driven by the double-acting hydraulic cylinders CY1 to CY3.
c An antenna 6 having a plurality of antenna elements provided in parallel in the excavation portion 4.
On the back surface of the back wall 13, closer to the bottom plate 14 (upper part of FIG. 5, lower part of FIG. 6) than the parallelogram links (10a to 10d, 11a to 11d), facing the tip of the boom 9 and outside (FIG. 6). An open recess 27 is formed on the inner surface side (diagonally lower left of FIG. 5 and diagonally lower left of FIGS. 7 and 8) open to the diagonally upper right of FIG. 5 and diagonally to the upper right of FIGS. 7 and 8. Paragraph [0036]), in the space of the recess 27, the antenna 6 is incorporated from the outside of the back wall 13 so as not to protrude to the outside, but is embedded and attached to the inside (paragraph [0037, 0039]), near the road surface. During ground penetrating (paragraph [0049]), the antenna 6 can be oriented downwards towards the ground (FIG. 1),
The antenna 6 is scanned by the plurality of antenna elements while gradually increasing the frequency from 200 MHz to 3 GHz to radiate the exploration electromagnetic wave, and receives the reflected wave by the target object of the exploration electromagnetic wave.
d The phase and amplitude of the received signal of the reflected wave received by the antenna 6 provided in the excavator main body 3 are measured and converted into time domain data, and the search is started based on the time domain data. A signal processing unit 7 that generates an image signal from to the end,
e Three-dimensional traveling direction, traveling perpendicular direction and depth direction (FIGS. 30A to 30C, FIGS. 31A to 31C) of the excavator main body 3 provided in the excavator main body 3 and generated by the signal processing unit 7. The image display unit 8 for displaying the image of the image signal of the above is provided.
f The signal processing unit 7
A plurality of frames featuring the target object are extracted from the received signal of the reflected wave received by the antenna 6 by the convolutional neural network, and the extracted frames are combined to generate the three-dimensional image signal. , When all the extracted target objects are displayed three-dimensionally in a plurality of frames on the image display unit 8 based on the generated image signal, and the detected target objects are derived from an underground pipe or cable. The three-dimensional display of the frame is emphasized in a different color (eg, red; paragraph [0056]) than the color (eg, black on a white background) when not derived from those buried pipes or cables. It is a characteristic underground radar exploration device .

Further, in the present invention, the signal processing unit extracts a plurality of frames featuring the target object from the received signal of the reflected wave received by the antenna by the convolutional neural network, and synthesizes each of the extracted frames. It is characterized in that the three-dimensional image signal is generated.

Further, the present invention is characterized in that the leakage electric field strength of the antenna is shielded to 35 μV / m or less.

The present invention is also characterized by further including a transmission unit that transmits an image signal generated by the signal processing unit to the image display unit by wireless communication.

According to the present invention, the underground radar exploration device according to the present invention is provided in an excavator including an excavator main body provided with an operating device and an excavating portion such as a bucket provided in the excavator main body. The operating device is operated by an operator, also called an operator, and in response to the operation of the operating device by the operator, the excavator main body travels and the excavator moves with respect to the excavator main body, and the ground or the ground or Underground excavation work is carried out.

The excavated part radiates exploration electromagnetic waves by scanning from multiple antenna elements of the antenna while gradually increasing the frequency from 200 MHz to 3 GHz, and receives reflected waves from the target object buried in the ground of the exploration electromagnetic waves. An antenna is provided. The excavator main body has a signal processing unit that generates a three-dimensional image signal based on the received signal of the reflected wave received by the antenna, and an image display unit that displays the three-dimensional image signal generated by the signal processing unit. And are provided. The signal processing unit generates a three-dimensional image signal from the received signal of the reflected wave, and the image of the three-dimensional image signal is displayed on the image display unit provided in the excavator main body.

In this way, the image display unit displays a three-dimensional exploration image of the reflected waves reflected by the target object, so even an operator who has no experience in radar exploration can see buried objects in the ground in the excavation target area. It is possible to easily and surely recognize the existence of the buried object and surely avoid damage to the buried object.

Further, according to the present invention, the signal processing unit extracts a plurality of frames featuring the target object by the convolutional neural network from the received signal of the reflected wave received by the antenna, synthesizes the extracted frames, and synthesizes the extracted frames. Since a three-dimensional image signal is generated and the image is displayed on the image display unit, even if the operator of the excavator is unfamiliar with the ground penetrating image, it is easy to see if there is an underground buried object in the excavation target area. Can be recognized.

Further, according to the present invention, since the leakage electric field strength of the antenna is shielded to 35 μV / m or less, there is no possibility of adversely affecting the surroundings such as radio wave interference, and the present invention is widely used as a weak radio device according to the Radio Law. It is possible to provide a ground penetrating radar exploration device with high versatility.

Further, according to the present invention, since the image signal generated by the signal processing unit is transmitted to the image display unit by wireless communication, for example, wireless LAN, by the transmitting unit, the image signal generated by the signal processing unit is displayed as an image. Signal lines such as communication cables for transmitting to the section are no longer required, preventing disconnection and damage due to movement of the excavator body and excavation section, contact with earth and sand, rocks, and surrounding structures during excavation, and excavation. It is possible to prevent the degree of freedom of the movement range and movement direction of the excavated part with respect to the machine body from being limited.

It is sectional drawing which shows the state at the time of the underground exploration of the excavator 1 equipped with the ground penetrating radar exploration apparatus of one Embodiment of this invention. It is sectional drawing which shows the state at the time of boom storage of the excavator 1. It is sectional drawing which shows the state at the time of excavation of the excavator 1. It is a front view of the image display unit 8. It is a perspective view which saw the bucket 4 from the bottom side. It is a perspective view which saw the bucket 4 from the opening side. It is sectional drawing of the bucket 4. It is a partially enlarged sectional view which shows the vicinity of the mounting part of the antenna 6 of a bucket 4. It is a perspective view which looked at the antenna 6 from the back side. It is a perspective view which saw the antenna 6 from the radiation surface side. It is a figure for demonstrating the principle of the ground penetrating radar. It is a figure which shows the relative permittivity of a typical target substance. It is a figure for demonstrating the principle of radar exploration. It is explanatory drawing which showed the image data acquired by radar exploration three-dimensionally. It is a figure which shows the radar waveform by the step frequency system of the antenna 6. It is a figure which shows the spectrum with respect to the frequency of the operation signal. It is a figure which shows the radar waveform of the ground penetrating radar exploration apparatus which concerns on embodiment of this invention. It is a figure for demonstrating the principle of the generation of a virtual image by the reaction of the foreign matter in the ground. It is a figure which shows an example of the display image displayed on the display surface of an image display unit 8. It is a figure which shows an example of the exploration image including a virtual image. It is a figure which shows the system structure of the convolutional neural network. It is a figure which shows typically the algorithm which creates the (n + 1) layer by convoluting the image data of the input n layers (where n is a positive integer). It is a figure which shows the display image 30 of the fully connected layer generated by performing the convolution process and the pooling process a plurality of times. It is an enlarged view of the part with a buried object in the display image 30. It is an enlarged view of the part without the buried object in the display image 30. It is a figure which shows the teacher data of the place where there is a buried object. It is a figure which shows the teacher data of the place where there is a buried object. It is a figure which shows the teacher data of the place where there is a buried object. It is a figure which shows the teacher data of the place where there is a buried object. It is a figure which shows the teacher data of the place where there is a buried object. It is a figure which shows the teacher data of the place where there is a buried object. It is a figure which shows the teacher data of the place where there is a buried object. It is a figure which shows the teacher data of the place where there is a buried object. It is a figure which shows the teacher data of the part without a buried object. It is a figure which shows the teacher data of the part without a buried object. It is a figure which shows the teacher data of the part without a buried object. It is a figure which shows the teacher data of the part without a buried object. It is a figure which shows the teacher data of the part without a buried object. It is a figure which shows the teacher data of the part without a buried object. It is a figure which shows the teacher data of the part without a buried object. It is a figure which shows the teacher data of the part without a buried object. It is a figure which shows the display image of the existence place of a foreign substance. It is a figure which shows the display image of the existence place of a foreign substance. It is a figure which shows the display image of the existence place of a foreign substance. It is a figure which shows the display image of the existence place of a foreign substance. It is a figure which shows the display image of the existence place of a foreign substance. It is a figure which shows the display image of the existence place of a foreign substance. It is a figure which shows the display image of the existence place of a foreign substance. It is a figure which shows the display image when a single buried pipe is detected. It is a figure which shows the display image when a plurality of buried pipes are detected. It is a figure which shows the display image when a plurality of buried pipes are detected.

(overall structure)
FIG. 1 is a cross-sectional view showing a state of an excavator 1 equipped with an underground radar exploration device according to an embodiment of the present invention at the time of underground exploration, and FIG. 2 is a cross-sectional view showing a state of the excavator 1 at the time of boom storage. 3A and 3B are cross-sectional views showing a state of the excavator 1 at the time of excavation, and FIG. 4 is a front view of the image display unit 8. The ground penetrating radar exploration device of the present embodiment is equipped on the excavator 1. The excavator 1 is provided with an operating device 2 operated by an operator, and is provided in an excavator main body 3 capable of traveling in response to the operation of the operating device 2 and an excavator main body 3 provided to operate the operating device 2. It includes a bucket 4 which is an excavator that can move in response. The excavator main body 3 has a pair of endless tracks 19 and can self-propell in any direction by operating the operating device 2.

The ground penetrating radar exploration device is provided in the bucket 4, emits an electromagnetic wave for exploration, and receives an antenna 6 that receives a reflected wave from an underground buried object 5 which is a target object of the electromagnetic wave for exploration, and an excavator main body 3. A signal processing unit 7 that generates a three-dimensional image signal based on the received signal of the reflected wave received by the antenna 6 and a three-dimensional unit 7 that is provided in the excavator main body 3 and generated by the signal processing unit 7. It is provided with an image display unit 8 for displaying the image signal of.

The image display unit 8 can be realized by a so-called in-vehicle display device such as a liquid crystal display device or a plasma display device. On the display screen of the image display unit 8, the signal processing unit 7 displays the following information as information to be taught to the operator who operates the excavator 1. To describe the display mode displayed on the display screen as an example, the signal processing unit 7 displays the current excavation information, the underground pipe, and the like in the first display image 8a, and the perspective in which the analysis result of the target section is schematicized. Fig second display image 8b displayed by such horizontal sectional view of an arbitrary depth of the third display image 8c horizontal cross-sectional view showing the probing depth range is displayed, the display screen 4 displays the switching button is displayed The image 8d and the fifth display image 8e for selecting the type of signal processing are displayed.

The display contents constituting the first to fifth display images 8a to 8e described above will be described as an example as follows. The first display image 8a shows "the number of exploration buried pipes: 1" indicating that one buried pipe was detected, and "current excavation depth" indicating the vertical distance of the bucket 4 from the ground surface. : -43.0 cm "," Depth of buried pipe 1: GL-50.0 cm "representing the detected depth of the buried pipe," Shortest distance to 1 "representing the shortest distance from the tip of the bucket 4 to the buried pipe 13.0 cm ”,“ Approach alarm: ON ”, which indicates that the approach alarm for notifying the existence of the buried pipe in the vicinity of the tip of the bucket 4 is in the ON state, and the like.

The second display image 8b is composed of a perspective view in which the analysis result of an arbitrary section is schematicized, and can visually teach the operator the buried object existing in the section investigated.

The third display image 8c is composed of a horizontal cross-sectional view or the like in which the analysis results of an arbitrary depth and section are schematicized, and can visually teach the operator the buried objects existing in the investigated depth and section.

The fourth display image 8d is composed of a plurality of selection buttons for switching a display mode such as a perspective view, a horizontal cross-sectional view, a vertical cross-sectional view, a cross-sectional view, and enlargement / reduction of the displayed exploration target image, and operates. A person can select and display an appropriate screen according to the situation.

The fifth display image 8e is composed of a plurality of selection buttons for selecting the radiation intensity of the electromagnetic wave radiated from the antenna 6 and the reception sensitivity for the reflected wave, and the operator performs appropriate signal processing according to the situation. You can choose.

In this embodiment, experience of radar exploration is performed in order to prevent the excavator 1, which is a construction machine represented by a backhoe, from being damaged by catching an underground buried object 5 such as a buried pipe or cables during excavation of a road surface. A specific example is described on the assumption that the existence or nonexistence of the underground buried object 5 can be clearly recognized from the radar exploration image to the operator who is the operator of the excavator who does not have the above. In order to excavate while monitoring the underground buried object 5, a separate radar operator is required in addition to the heavy equipment operator, but when the excavation depth becomes deep, it is highly dangerous for humans to enter the excavation range and repeat the exploration. Not realistic. Therefore, in the present embodiment, the artificial intelligence AI is applied to the radar exploration image determination, and the underground buried object 5 is displayed in real time on the screen of the image display unit 8 of the operator's seat of the excavator 1 in an easy-to-understand manner. This allows heavy equipment operators who have no experience in radar image analysis to perform buried object confirmation and excavation work by themselves.

The radar probe of the prior art can capture the underground buried object 5 from the road surface to a depth of about 1.5 m, but the deeper the depth, the weaker the reflection intensity, so that the radar exploration image becomes difficult to read. According to this embodiment, the excavation depth is about 0.5 m, which is the range where the most sensitivity can be obtained even with a conventional radar probe. Therefore, by repeating this, high-precision exploration can always be performed. It is possible and it is possible to carry out safer excavation work. In addition, by repeating exploration → excavation → exploration → excavation ..., the excavation work is safe while monitoring the underground buried object 5 endlessly to a depth deeper than the depth of about 1.5 m that can be radar explored from the ground. Can be repeated.

In the present embodiment, in order to prevent the excavator 1, which is a construction machine, from being damaged by catching the underground buried objects 5 such as buried pipes and cables during excavation of the road surface, the excavator has no experience in radar exploration. A specific example in which the existence or nonexistence of the underground buried object 5 can be clearly recognized from the radar exploration image will be described to the operator who is the operator of the above.

5 is a perspective view of the bucket 4 as viewed from the bottom side, FIG. 6 is a perspective view of the bucket 4 as viewed from the opening side, FIG. 7 is a cross-sectional view of the bucket 4, and FIG. 8 is a sectional view of the bucket 4. It is a partially enlarged sectional view which shows the vicinity of the mounting part of the antenna 6. The bucket 4 has a back wall at the tip of the boom 9 extending from the excavator main body 3 by a parallelogram link composed of four link pins 10a, 10b, 10c, 10d and link members 11a, 11b, 11c, 11d. A portion of 13 opposite to the bottom plate portion 14 (upper portion of FIG. 6) is tiltably connected with respect to the tilt center axis L1. The tilt center axis L1 is substantially horizontal in the normal state, although it depends on the posture of the excavator 1, and each axis of the four link pins 10a to 10d is parallel to the tilt center axis L1. Both ends in the axial direction of the link pin 10d are pin-coupled to one end of the link member 11c, and both ends in the axial direction of the link pin 10c are pin-coupled to the other end of the link member 11c. The link member 11c is composed of the tip end portion of the boom 9. As shown in FIG. 1, during the underground exploration, the antenna 6 is turned downward toward the ground.

The tip of the piston rod CY11 of the double-acting hydraulic cylinder CY1 is rotatably connected to the axial middle portion of the link member 10d. The boom 9 has two arms 21 and 22, a connecting pin 23 for pin-coupling each end of each arm 21 and 22 adjacent to each other, and one end of one arm 22 on the excavator body 3 side is the excavator body 3. It has a connecting pin 24 that is pin-coupled to. A double-acting hydraulic cylinder CY2 is connected to the excavator main body 33 by, for example, a trunnion joint. The tip of the piston rod CY21 of the double-acting hydraulic cylinder CY2 is pin-coupled to a substantially central portion in the longitudinal direction of the arm 22 by an intermediate pin 25. A double-acting hydraulic cylinder CY3 is pin-coupled to the intermediate pin 25 by, for example, a trannyon joint in the same manner as the above-mentioned double-acting hydraulic cylinder CY2, and the tip of the piston rod CY31 of the double-acting hydraulic cylinder CY3 is the other arm 21. It is pin-coupled to one end of the.

The bucket 4 has a pair of side walls 12a and 12b extending along a plane perpendicular to the tilting center axis L1, a back wall 13 having a substantially C-shaped cross section perpendicular to the tilting center axis L1, and a flat bottom plate portion. 14 and. The bucket 4 is made of steel, for example. The side edges of the back wall 13 and the bottom plate 14 on both sides in the direction parallel to the tilting center axis L1 are joined to the peripheral edges of the side walls 12a and 12b by welding or the like. The side walls 12a and 12b, the back wall 13, and the bottom plate portion 14 form a storage space that can accommodate the excavated earth and sand through the openings. On the bottom plate portion 14, a plurality of claw members 15 are aligned with each other along the tilting center axis L1 at an opening side edge parallel to the tilting center axis L1 facing the opening, and are aligned with each other by bolts, nuts, or the like. It is fixed. When each claw member 15 is deformed or worn, the bolt and nut can be removed and replaced with a new one. The excavated portion 4 has a pair of side walls 12a and 12b extending along a plane perpendicular to the horizontal tilting center axis L1 and a cross section perpendicular to the tilting center axis L1 between the side walls 12a and 12b curved in a C shape. The wall 13 and the flat bottom plate portion 14 extending from the back wall 13 to the opening side (diagonally lower left in FIG. 6, left in FIG. 7) and to which a plurality of claw members 15 are fixed to the opening side edge portion. It is a bucket that constitutes a storage space for accommodating excavated earth and sand.

An antenna 6 is assembled and attached to the back wall 13 from the outside of the back wall 13. The reason why the antenna 6 is incorporated and attached to the back wall 13 from the outside in this way is to prevent damage due to collision of earth and sand, rocks, etc. during excavation. The configuration of the attachment portion of the antenna 6 to the back wall 13 will be described.

On the back surface of the back wall 13, closer to the bottom plate 14 (upper in FIG. 5, lower in FIG. 6) than the parallelogram links (10a to 10d, 11a to 11d) , facing the tip of the boom 9 and outside (FIG. 6). An open recess 27 is formed on the inner surface side (diagonally lower left of FIG. 5 and diagonally lower left of FIGS. 7 and 8) open to the diagonally upper right of FIG. 5 and diagonally to the upper right of FIGS. 7 and 8. .. The antenna 6 and the cover member 28 that covers the antenna 6 are fitted in the space of the recess 27. The cover member 28 is made of a material that does not interfere with the emission of electromagnetic waves from the antenna 6 and the incident of reflected waves, for example, bakelite. The cover member 28 prevents collisions of earth and sand, rocks, equipment and tools, and protects against muddy water, rainwater, and adhesion of concrete before hardening caused by construction work. Attenuation of the radiant intensity and incident intensity of electromagnetic waves is prevented.

(Antenna configuration)
FIG. 9 is a perspective view of the antenna 6 as viewed from the back surface side, and FIG. 10 is a perspective view of the antenna 6 as viewed from the radiation surface side. The antenna 6 is composed of a multi-arranged antenna in which a plurality of antenna elements are arranged in a row, and the number of antenna elements varies depending on the width B of the bucket 4, but in each case, the antenna 6 is attached to the outside of the back surface of the bucket 4 and is mounted from the surface. It is configured to be embedded inside without protruding. By using a multi-arranged antenna, information such as the burial direction, burial gradient, and burial depth of buried pipes and cables in the ground can be acquired by one antenna scan.

The antenna 6 uses an air couple type multi-arranged step frequency type ultra-wideband dipole antenna, has a wide frequency band of 50 MHz to 10 GHz, and obtains exploration image information with high resolution in all depth bands from shallow to deep layers. be able to. In the present embodiment, the "shallow layer" is a range in which the depth from the ground is 0 m or more and 0.1 m or less, and the "deep layer" is a depth from the ground of more than 0.1 m and 2.0 m or less. Is the range of. When the antenna 6 is mounted inside the bucket 4, when the underground buried object 5 in the front direction of excavation is explored, the leakage electric field strength from the antenna element is the reference value specified in the Radio Law Enforcement Regulations, for example, the frequency band is 322 MHz. When the frequency exceeds 10 GHz, it is necessary to satisfy that the electric field strength at a position with a radius of 3 m from the radio wave generation source is 35 μV / m or less. In this embodiment, for each pair of antenna elements for transmission and reception of the antenna 6. The structure is such that the leaked radio wave can be blocked by ferrite, and the leaked magnetic field strength can satisfy the standard value stipulated in the Radio Law Enforcement Regulations.

The antenna 6 attached to the back surface of the bucket 4 does not protrude outward and has a structure that bulges inward, and the load due to contact with the excavated object such as earth and sand during excavation is directly applied to the antenna 6. It has a structure that does not act on the radiation / incident surface. Further, the amount of protrusion ΔL to the inner surface side of the bucket 4 is about 3 cm, and there is almost no influence on the excavation ability.

An angle sensor or an encoder is attached to each joint of the boom 9 of the excavator 1, and the horizontal movement amount and the vertical movement amount of the antenna 6 are accurately calculated from the movement of each joint, and the buried object is buried in the ground. Information on the distance to 5 and the depth of excavation is input to the signal processing unit 7 in real time. As a method for detecting the movement of each joint, an acceleration sensor that detects acceleration in the orthogonal three-axis directions may be used instead of the angle sensor and the encoder.

(Principle of ground penetrating radar)
FIG. 11 is a diagram for explaining the principle of ground penetrating radar. Electromagnetic waves transmitted under the road surface travel in a non-reflective state in a homogeneous component, but reflected waves are generated at the interface between substances having different electrical properties. As shown in FIG. 11, when an electromagnetic wave is radiated from a transmitting antenna toward the bottom of the road surface, the electromagnetic wave is reflected at a boundary surface with a substance having different electrical properties, for example, a reflective object such as concrete, a reinforcing bar, or a cavity, and is again on the concrete surface. And reach the receiving antenna. By measuring the distance to the reflecting object including the underground buried object 5 from the arrival time and moving the antenna on the road surface, the position where the distance becomes the minimum value can be estimated as the position on the plane. The depth D to the reflecting object is expressed by the following equation 1.

FIG. 12 is a diagram showing the relative permittivity of a typical target substance. The relative permittivity is the ratio of the permittivity of the target substance to the permittivity in vacuum, and is related to the propagation loss in the ground. The smaller the relative permittivity, the smaller the propagation loss. Therefore, the smaller the relative permittivity, the deeper the exploration depth.

(Principle of 3D radar system)
FIG. 13 is a diagram for explaining the principle of the 3D radar system, and FIG. 14 is an explanatory diagram showing image data acquired by radar exploration in three dimensions. A 3D radar system is used for the ground penetrating radar of the present embodiment. The 3D radar system employs a multi-channel antenna array system consisting of multiple antenna elements in parallel, and by scanning, image data for analysis by a convolutional neural network, which corresponds to 20 to 30 survey lines, is acquired at once. can do. Further, as shown in FIG. 15 described later, a step frequency method is adopted in which the minimum width frequency is gradually increased every 2 MHz from 200 MHz in the frequency domain to be transmitted and received, so it is necessary to use different antennas for each target depth. It is possible to acquire the data of each depth from one antenna array. With such a configuration, it is possible to facilitate and improve the accuracy of three-dimensional interpretation of underground information with higher accuracy.

Further, the antenna 6 is composed of an air couple bow tie pole pair, and can be explored at high speed with the ground height separated by a maximum of 30 cm. Such a 3D radar system is stored as an application program in a storage unit such as a ROM (Read Only Memory) of the signal processing unit 7, and by executing this, 3 for analysis by the above-mentioned convolutional neural network is performed. Dimensional image data can be acquired.

(About the step frequency method)
FIG. 15 is a waveform diagram showing a radar waveform according to the step frequency method of the antenna 6, FIG. 16 is a diagram showing a spectrum with respect to the frequency of the operating signal, and FIG. 17 is a diagram showing a waveform distribution due to an ultra-high band frequency response. .. The step frequency is a radar waveform consisting of a continuous sine wave that increases linearly. The 3D radar system measures the phase and amplitude for each frequency, and an inverse Fourier transform process is performed to construct a time domain profile (A-scan) from the acquired data. In the 3D radar system, the data collected in the frequency domain is converted into the time domain data by performing the above-mentioned processing on the computer. In addition, the signal processing unit can set the dwell time (Dwell Time) over each frequency transmitted and received from the start to the end of the exploration by computer control.

As a comparative example, a pulse wave radar is a strobe that emits a very short pulse wave with a constant pulse repetition rate (PRF) and traces from several continuous pulses to build a time region. Sampling is adopted. Since the strobe sampling directly acquires the time domain data of the reflected wave, the energy loss is large and the frequency domain is also limited. On the other hand, the raw data acquired by the above-mentioned 3D radar system can be captured and stored as time domain data derived by the inverse Fourier transform of the frequency domain data. The time domain data acquired by the 3D radar corresponds to the time domain data acquired by the pulse wave radar, but the frequency domain data in the 3D radar enables processing in a wider frequency domain.

The ground penetrating radar of the present embodiment, which is a 3D radar system that employs an ultra-wideband bow tie monopole, covers a continuous frequency band from 200 MHz to a maximum of 3 GHz, as shown in FIG. 17 above. ing. Therefore, if the same investigation is to be performed using a pulse wave radar, it is necessary to prepare antennas of 200 MHz, 400 MHz, 1000 MHz, and 2000 MHz, respectively, but the ground penetrating radar exploration device of the present embodiment replaces the antenna 6. It is possible to collect data in a frequency band of 200 MHz or more and 3 GHz or less without any problem.

(Procedure for exploration and excavation)
The procedure of exploration and excavation by the ground penetrating radar of this embodiment is as follows.
(1) The toe of the bucket 4 is brought into contact with the road surface to be excavated, the depth at this time is measured by an angle sensor or an encoder attached to the boom 9, and the depth is stored in the storage device of the signal processing unit 7 as 0 m.

(2) Before excavation, radar exploration is conducted from the road surface to the excavation range, and confirmation exploration is carried out to confirm whether or not the underground buried object 5 exists in the ground near the road surface. The result of the exploration is that the display screen of the image display unit 8 installed in the driver's seat displays the underground condition up to about 1.0 m underground in three dimensions in real time, making it easy for the operator to decide whether or not to start excavation. You can make a definite judgment.

(3) Since the excavation depth by one scan is considered to be about 30 cm to 50 cm when excavating without underground exploration, the exploration up to about 1.0 m in the ground obtained by the confirmation exploration before excavation If it is determined that the underground buried object 5 does not exist, excavation to a depth of 1.0 m may be carried out at once, but it is desirable to carry out confirmation exploration every 50 cm of excavation depth from the safety side.

(4) When there is a reaction of the underground buried object 5 in the ground, the current excavation depth and the depth up to the underground buried object 5 are displayed in real time on the display screen of the image display unit 8, and the present The shortest distance from the tip of the bucket 4 to the underground buried object 5 can also be confirmed. In addition, when the distance between the tip of the toe and the buried object 5 is 20 cm or less, an approach warning is automatically issued, for example, an alarm sound is generated by a buzzer provided in the driver's seat and the alarm lamp blinks or one of them. It has a function to issue an alarm.

FIG. 18 is a diagram for explaining the principle of generation of a virtual image due to the reaction of a foreign substance in the ground, FIG. 19 is a diagram showing an example of a display image displayed on the display screen of the image display unit 8, and FIG. 20 is a diagram. It is a figure which shows an example of the exploration image including a virtual image, and FIG. 21 is a figure which shows the system structure of the convolutional neural network. The signal processing of the exploration signal obtained by using the antenna 6 will be described. In order to extract a clear exploration image from the signal received by the reflected wave received by the antenna 6, a higher level of features is learned by introducing a convolutional neural network (CNN) that excels in recognizing image data. However, since it is possible to perform image extraction specialized for the underground buried object 5 and it is robust against the displacement of the position of the object, it can detect the feature with high accuracy no matter where it is in the input data. Has a mobile invariance that can be.

FIG. 22 is a diagram schematically showing an algorithm for creating a (n + 1) layer by convolving the input image data of the n layers (where n is a positive integer), and FIG. 23A shows the convolution process. It is a figure which shows the display image 30 of the fully connected layer generated by performing the pooling process a plurality of times. FIG. 23B is an enlarged view of a portion without buried objects in the display image 30, and FIG. 23C is an enlarged view of a portion with buried objects in the display image 30. The neural network includes an input layer, a convolution layer, a pooling layer, a fully connected layer and a classification layer. The convolutional layer is for extracting the features of the input image information, and is composed of a plurality of feature maps. Each neuron in each feature map is connected to an adjacent neuron in the previous layer, and the input feature map and the trained convolution kernel (also called a filter or feature detector) are used to calculate a new feature map. ) And give the result to the activation function. The pooling layer is for obtaining spatial invariance by reducing the resolution of the feature map and is located between the two convolutional layers. The feature map of each pooling layer is connected to the feature map of the corresponding previous convolutional layer to extract the average pooling and the maximized pooling. A more abstract feature map is extracted by superimposing several convolutional layers and pooling layers. After the last convolutional layer and pooling layer, there is one or more fully connected layers, each neuron in the fully connected layer is connected to all the neurons in the previous layer, respectively, and the final image file is Be extracted.

24A to 24H are diagrams showing teacher data of a portion with a buried object, and FIGS. 25A to 25H are diagrams showing teacher data of a sound portion. When the part without the buried object is extracted from the position other than the part with the buried object, the image data is extracted as shown in FIG. 24A. When a portion without a buried object is extracted as image data of a certain size, the image data is extracted as shown in FIG. 24B. The teacher data of the place where there is a buried object is extracted as image data as in each example of FIGS. 24C to 24H. The teacher data of the portion without the buried object is extracted as image data as in each example of FIGS. 25A to 25H.

26 to 29 are views showing display images of locations where foreign substances are present. When a foreign substance is present in the basement, as in each example of FIGS. 26 to 29, a plurality of rectangular frames are displayed overlapping in red, and the place where the foreign substance is present is highlighted in three dimensions.

30A to 30C are views showing display images when a single buried pipe is detected. The detection result when the entire section to be explored is explored is displayed three-dimensionally in a frame of the same color for all the detected buried objects as shown in FIG. 30A. The place where each frame is displayed relatively densely is assumed to be an embedded pipe, and if a black frame is displayed in another color, for example, a white background, as shown in FIG. 30B, the other color is displayed. It is displayed in three dimensions by emphasizing it with a different color, for example, a red frame. Further, when the entire section is explored and it is determined that the frame is derived from the buried pipe, only the frame of the buried object is highlighted in red and displayed three-dimensionally as shown in FIG. 30C.
The image display unit 8 is provided in the excavator main body 3, and as shown in FIGS. 30A to 30C and FIGS. 31A to 31C described below, the traveling direction and traveling of the excavator main body 3 generated by the signal processing unit 7 are provided. Displays an image of a three-dimensional image signal in the perpendicular direction and the depth direction.

31A is a diagram showing a display image when a single buried pipe is detected, FIG. 31B is a diagram showing a display image when a plurality of buried pipes are detected, and FIG. 31C is a diagram showing a display image when a plurality of buried pipes are detected. It is a figure which shows the display image at the time of this. As shown in FIG. 31A, all the buried objects detected by exploring the entire section are displayed three-dimensionally, and it can be seen that all the buried objects are single buried pipes. Further, when it is determined that the material is derived from the buried pipe among all the buried objects, as shown in FIG. 31B, only the buried pipe is highlighted in red, which is different from the others, and displayed three-dimensionally. NS. Further, when the frame other than the buried pipe is removed from all the detected buried objects, only the buried pipe is three-dimensionally displayed as shown in FIG. 31C.

As described above, according to the present embodiment, the antenna 6 is integrally provided in the bucket 4 which is an excavation part for excavating the earth and sand of an excavator such as a power shovel and a backhoe. When excavating the ground using the bucket 4, an accident can be prevented by forcibly stopping the bucket 4 as soon as the existence of the underground buried object 5 is confirmed within the exploration range of the antenna 6. This system eliminates the need for pre-construction surveys, which not only shortens the construction period, but also significantly reduces accidents caused by operator carelessness or operational mistakes.

The underground laser exploration device according to the present invention is mounted on an excavation machine such as a backhoe and is not only carried out for exploration of buried pipes and cables in the ground, but also for exploration of buried land mines left in conflict countries, for example. Can also be suitably carried out. In addition, by mounting it on an automobile or track vehicle, it is possible to suitably carry out ground penetrating radar and cavity exploration on the back surface of tunnel lining while moving at high speed.

1 Excavator 2 Operation device 3 Excavator body 4 Bucket 5 Underground buried object 6 Antenna 7 Signal processing unit 8 Image display unit 9 Boom 10a, 10b, 10c, 10d Link pin 11a, 11b, 11c, 11d Link member 12a, 12b Side wall 13 Back wall 14 Bottom plate 15 Crawler belt 21, 22 Arm 23 Connecting pin 24 Connecting pin 25 Intermediate pin 27 Recess 28 Cover member CY1, CY2, CY3 Double-acting hydraulic cylinder CY11, CY21, CY31 Piston rod L1 Tilt center axis

Claims (3)

An excavator main body that is provided with an operating device operated by an operator and can travel in response to the operation of the operating device, and an excavator that is provided in the excavator main body and can move in response to the operation of the operating device. An underground radar exploration device provided in the excavator 1 including,
b The excavated part
A pair of side walls extending along a plane perpendicular to the horizontal tilt center axis,
A back wall whose cross section perpendicular to the tilt center axis is curved in a C shape between the side walls,
With a flat bottom plate extending from the back wall to the opening side and fixing multiple claw members to the opening side edge,
It is a bucket that constitutes a storage space for accommodating excavated soil.
A parallelogram link at the tip of the boom extending from the excavator body connects the part of the back wall opposite to the bottom plate so that it can be tilted with respect to the center axis of tilt.
The boom and parallelogram link are driven by a double-acting hydraulic cylinder and
c An antenna having a plurality of antenna elements provided in parallel in the excavated portion.
On the back of the back wall, closer to the bottom plate than the parallelogram link, a recess is formed that faces the tip of the boom and opens outward and bulges inward, and the antenna is placed outside the back wall in the space of this recess. It is built in from and does not protrude to the outside, but is embedded and attached to the inside, and when exploring the ground near the road surface, the antenna can be turned downward toward the ground.
This antenna is an antenna that radiates an electromagnetic wave for exploration by scanning while gradually increasing the frequency from 200 MHz to 3 GHz by the plurality of antenna elements, and receives a reflected wave by the target object of the electromagnetic wave for exploration.
d The phase and amplitude of the received signal of the reflected wave received by the antenna, which is provided in the excavator main body, is measured and converted into time domain data, and the exploration starts and ends based on this time domain data. The signal processing unit that generates the image signals up to
e. An image display unit provided on the excavator main body and displaying an image of three-dimensional image signals in the traveling direction, the traveling perpendicular direction, and the depth direction of the excavator body generated by the signal processing unit is provided.
f The signal processing unit
A plurality of frames featuring the target object are extracted from the received signal of the reflected wave received by the antenna by the convolutional neural network, and the extracted frames are combined to generate the three-dimensional image signal. Based on the generated image signal, all the extracted target objects are displayed three-dimensionally in multiple frames on the image display unit, and if the detected target objects are derived from buried pipes or cables in the ground, they are displayed. An underground radar exploration device characterized by displaying the frame in three dimensions by emphasizing it with a color different from the color when it is not derived from the buried pipe or cable of the above. The ground penetrating radar exploration device according to claim 1, wherein the antenna is shielded from a leakage electric field strength of 35 μV / m or less. The ground penetrating radar exploration device according to claim 1 or 2, further comprising a transmission unit that transmits an image signal generated by the signal processing unit to the image display unit by wireless communication.

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