JPH0249188A - Obstacle detecting device for civil work machine - Google Patents

Abstract

PURPOSE:To discriminate between a long and a short buried body and to increase the detection accuracy by constituting a transmission/reception antenna for detection in a up-down and right-left displaceable state and forming a front member to be provided in front of the antenna by using a nonmetallic material. CONSTITUTION:The nonmetallic front member 3 is provided to the tip part 2 of the civil work machine which is propelled in the ground to dig and the transmission antenna 5 and reception antenna 6 for buried body detection are provided to the back surface part of the member so that they can slant and rotate in the up-down and right- and left directions. The transmission antenna 5 transmits the fed electric power from a transmission circuit 11 into the ground and the reception antenna 6 receives the reflected electric power from a buried body and supplies it to a reception circuit 12 to detect the buried body. Consequently, the specific dielectric constant of the front surface member 3 is equalized to that of said body, so the detection accuracy of the buried body can be improved. Further, the antennas 5 and 6 can be changed in the right-left and up-down directions, etc., so whether the buried body is long or short can be decided.

Description

[Detailed Description of the Invention] [Objective of the Invention 1 (Field of Industrial Application) This invention relates to an obstacle detection device attached to a civil engineering machine such as a propulsion machine that pushes soil or an excavator that excavates, This system detects buried objects, etc. that exist ahead in the direction of travel, and also determines whether the buried objects, etc. are short or long objects, so that obstacles can be accurately detected.

(Prior art) Obstacle detection devices installed in civil engineering machines such as propulsion machines or excavators transmit electromagnetic waves into the ground, receive reflected waves from obstacles, and detect them. It is known that this was done.

By the way, the functional plate at the tip of such a civil engineering machine is
High-strength steel materials are used because a large load is applied to spread or excavate the soil. For this reason,
Even if the transmitting and receiving antenna elements are attached to the back side of the tip front plate made of such a material, the electromagnetic waves transmitted from the transmitting antenna element will be transmitted to the inner side of the tip front plate made of steel. The electromagnetic waves cannot be transmitted into the ground because they are totally reflected.

The first conventional example that addresses this issue is an obstacle detection device for a shield excavator equipped with four cutter spokes at the tip of the machine, which prevents the reflection of transmitted electromagnetic waves by the cutter spokes. For this reason, some machines are equipped with a rotational pulse transmitter and a cutter spoke position calculator connected to the cutter rotation motor shaft, and are designed to emit transmitting electromagnetic waves from the antenna only during periods when the cutter spokes are not blocking the cutter spokes. Japanese Patent Publication No. 60-261892
Publication No.).

However, in the first conventional example, the device configuration for detecting the non-blocking time period due to the plurality of cutter spokes is complicated, and obstacles are detected by reflected waves received only during the non-blocking time period. Therefore, there was a problem in that it was difficult to accurately detect obstacles.

In addition, there is a second conventional example of the l[I harmful object detection device that detects obstacles such as objects buried underground from the ground.

In this second conventional example, the wavelength of the electromagnetic waves emitted into the air from the transmitting antenna is 3m to 500m (corresponding to a frequency of about 100MH7 to 600MH2) in order to increase the reach distance of the electromagnetic waves and improve detection performance. A certain degree is used. The antenna element for transmitting and receiving electromagnetic waves in this band has a negative side of 30 to 4.
0 cm is used. If an antenna element of such a large size can be attached to the tip of a civil engineering machine, it is possible to realize an obstacle detection device for a civil engineering machine that has a detectable distance comparable to that of an obstacle detection device from the ground. However, when an antenna element of the above-mentioned size is attached to the tip of a civil engineering machine, the area occupied by the antenna element becomes large depending on the type of civil engineering machine, which may make attachment difficult.

To solve this problem, if the dimensions of the antenna element are simply reduced to 1/n (n>1), the applicable wavelength becomes 1/n, the frequency increases by n times, and the reach of electromagnetic waves becomes shorter. This will reduce the detectable distance.

(Problems to be Solved by the Invention) Conventional civil engineering machines had a front plate made of steel on the front side, so even if a transmitting antenna element was attached to the back side of the front plate, The electromagnetic waves used for transmission are totally reflected on the back side of the front panel, making it impossible to transmit the electromagnetic waves into the ground.

In addition, in the first conventional example, the device configuration for detecting non-blocking time periods using a plurality of cutter spokes is complicated, and obstacles are detected by reflected waves received only during non-blocking time periods. Therefore, it is difficult to accurately detect obstacles.

Furthermore, in order to obtain the same detection distance as the second conventional example, which is an obstacle detection device from the ground, the size of the antenna element would be relatively large, so it must be attached to the tip of the machine. The problem was that it was difficult.

In addition, underground objects detected by obstacle detection equipment include:
For example, there are short objects such as stones and long objects such as communication pipes.In the case of short objects such as stones, the propulsion device may be able to propel them as is, but the communication pipes In the case of long objects such as the above, they cannot be propelled and become obstacles. Therefore, in order to improve the obstacle detection function, an obstacle detection device is required to have a function to detect buried objects as well as a function to determine whether the buried object is short or long. There is.

This invention was made based on the above-mentioned circumstances, and it detects buried objects, etc. that exist ahead in the direction of travel, and also determines whether the buried objects are short or long objects to accurately identify obstacles. An object of the present invention is to provide an obstacle detection device for civil engineering machinery that can detect obstacles.

[Structure 1 of the Invention (Means for Solving the Problems) In order to solve the above problems, the present invention provides a non-metallic material that is attached to the tip of a civil engineering machine that propels or excavates underground and has the required strength. a front member made of aluminum, a transmitting and receiving antenna that is arranged on the back side of the front member and transmits and receives radio waves for detecting buried objects through the front member, and a transmitting and receiving antenna that is arranged in the vertical and horizontal directions. a driving means that tilts or rotates to vary the transmission and reception directions of the radio waves;
The gist of the present invention is to include transmitting and receiving circuits that feed transmitting power between the transmitting and receiving antennas and receive received power based on radio waves reflected from buried objects.

(Function) In the above configuration, since the front member in contact with the soil is made of a non-metallic material, its relative permittivity can be set to a value substantially close to the relative permittivity of the soil.

Therefore, the reflection of electromagnetic waves at the boundary between the front member and the soil can be reduced, and the radio waves emitted from the transmitting antenna can efficiently pass through the front member and reach the soil in front of the civil engineering machine in the direction of movement. sent during. Further, reflected radio waves from obstacles also efficiently pass through the front member and are received by the receiving antenna in the same manner as described above. Therefore, buried objects and the like existing ahead in the direction of travel can be efficiently detected.

In addition, the driving means tilts or rotates the antenna vertically and horizontally to change the direction of transmitting and receiving radio waves, and the reflected radio waves detect whether the buried object is short or long. It is determined whether the object is an object or not. Thus, the presence of obstacles can be accurately detected.

(Example) Hereinafter, an example of the present invention will be described based on the drawings. 1 to 6 are diagrams showing a first embodiment of the present invention. This embodiment is applied to a propulsion device, and the antenna element is tilted vertically and horizontally.

First, to explain the configuration of an obstacle detection device for civil engineering equipment, a ceramic front plate 3 as a front member is attached to the tip 2 of a steel propulsion tube 1, which is a component of the civil engineering equipment. There is. The front plate 3 is appropriately thicker than that made of steel in order to have the same strength as that made of steel.

During use, the outer surface of this front plate 3 is made of soil (relative dielectric constant = 2~
80). Generally, electromagnetic waves are reflected at the boundary between materials with different dielectric constants, but by using ceramics as the material of the front plate 3 as described above, the dielectric constant of the front plate 3 can be adjusted to match the dielectric constant of soil. The values can be made to be approximately the same, and the anti-tA period of electromagnetic waves at the contact surface can be suppressed to an extremely small value.

There are many types of ceramics having such a dielectric constant, such as alumina, beryllia, and barium ceramics. In addition to the above-mentioned ceramics, the material for the front plate 3 may be plastic, FRP ( It is also possible to use rubber in which carbon is dispersed in a predetermined proportion.

Further, the center portion of the back side of the front plate 3 described above is recessed in a spherical shape, and the sliding plate 4 as a sliding member having a convex surface corresponding to this recessed portion is in close contact with the recessed portion. The thin mating plate 4 mounted on the front plate 3 is made of a material having the same dielectric constant as the front plate 3.

A transmitting antenna element 5 and a receiving antenna element 6 made of steel plates are attached to the front side of a radio wave absorber 7 which also serves as a mounting member on the back side of the matching plate 4. A drive arm 8 is attached to the back side of the radio wave absorber 7, and this drive arm 8 is connected to a drive means to be described later.

Generally, the speed of electromagnetic waves in a dielectric material having a relative dielectric constant ε is 1/ε8 of that in air. Therefore, even if the transmitting and receiving antenna elements 5.6 are downsized to 1/n, if they are passed through a dielectric material of ε-n2 as described above, the frequency of the electromagnetic waves remains unchanged and detection This prevents the possible distance from decreasing.

Further, a mounting plate 9 integrally formed with the steel propulsion tube 1 is provided at the rear of the drive arm 8, and the antenna elements 5 and 6 for transmitting and receiving are mounted on the mounting plate 9 in the vertical and vertical directions. A driving means for changing the transmission direction of emitted radio waves by tilting in the left-right direction, a transmitting circuit 11, and a receiving circuit 12 are attached. A compression mechanism 17 made of a spring or cushion material is provided between the drive arm 8 and the mounting plate 9 in order to eliminate the gap between the front plate 3 and the contact plate 4 and reduce the loss of transmitted and received electromagnetic waves. has been done.

The driving means includes, for example, a worm gear mechanism 13 as a means for tilting in the vertical direction, a bevel gear mechanism 14 as a means for tilting in the left-right direction, and a drive motor 10 for driving both of these mechanisms 13 and 14. . Both mechanisms 13 and 14 are configured such that the rotation axis of the worm gear J3 in the worm gear mechanism 13 corresponds to the rotation axis of the small gear in the bevel gear mechanism 14. and,
The worm gear mechanism 13 and the bevel gear mechanism 14 are configured to operate in a connected state by a clutch mechanism or the like, and by releasing the clutch mechanism or the like, these two mechanisms 13 and 14 can operate independently. There is.

Therefore, antenna elements 5.6 for transmitting and receiving
is rotated in the vertical and horizontal directions by the worm gear mechanism 13 or the bevel gear mechanism 14 about the approximate center of the drive arm 8, and furthermore, by the interlocking operation of both mechanisms 13 and 14, the approximate center of the drive arm 8 is rotated. It is configured so that it can move along a spherical surface centered on .

Further, the transmitting circuit 11 is connected to the transmitting antenna element 5 through a cord 15, and the receiving circuit 11 is connected to the receiving antenna element 6 through another cord. As shown in FIG. 4, a transmitting/receiving shield 16 is provided between the transmitting circuit 11 and the receiving circuit 12.

The transmitting circuit 11 and the receiving circuit 12 further include a connector 18.
and is connected to the control processing section 20 via a cable 19. The υIt'll processing unit 20 has a propulsion control line function for the civil engineering work area, and also issues an alarm when it receives a detection signal for buried objects etc. from the receiving circuit 12, and at the same time causes the drive means 10 to drive. It also has a function to send a start signal. The control processing section 20 is also equipped with a display section 22 for displaying the reflected waveform from the buried object 21, and the like.

Since the obstacle detection device for civil engineering machinery of this embodiment is configured as described above, high-frequency pulses, which are electromagnetic waves, are emitted from the transmitting antenna element 5 by feeding the transmitting power from the transmitting circuit 11. Then, the electromagnetic waves efficiently pass through the contact surface between the ground plate 4 and the back surface of the front plate 3, and the contact surface between the front plate 3 and its outside and the soil, and reach the soil in front of the tip section 2 in the direction of movement. sent during. If there is a buried object 21 in the soil ahead in the direction of travel, the reflected radio waves will efficiently pass through the contact surface between the outer surface of the front plate 3 and the soil in the opposite direction to the receiving antenna. The wave is received by element 6.

The reflected radio waves received in this manner are sent to the control processing section 2o via the receiving circuit 12, and the waveform is displayed on the display section 22, so that the presence of the buried object 21 is detected. Fig. 5 shows a 75mm hole buried approximately 1m deep in front of the tip 2.
It shows an example of the waveform of a reflected radio wave that detected a φ pipe as a buried object 21.

In the same waveform diagram, Pl indicates the peak of the electromagnetic wave that directly went around from the transmitting antenna element 5 to the receiving antenna element 6, and Pl indicates the peak due to the reflected radio wave from the 75 mmφ pipe that is the buried object 21. The buried object 21 is detected from this peak signal P2.

However, even if buried objects 21 are detected, if things continue as they are,
It is difficult to determine whether the buried object 21 is a short object, such as a stone, which allows the nt advance to proceed as is, or a long object, such as a communication pipe, that will become an obstacle.

Therefore, when the presence of the buried object 21 is confirmed by the control processing section 20 upon receiving the reflected radio wave from the reception circuit 12, the control processing section 20 issues an alarm and at the same time,
A drive start signal is sent to , the drive means is activated, the tilting or rotating operation of the antenna element 5.6 is started, and an operation for determining whether the buried object 21 is a short object or a long object r is performed.

(A) and (B) in Figure 6 show the detection results when a long object such as a communication pipe is buried in front of the tip 2 and when a short object such as a stone is present. This is an example. First, FIG. 6(A) shows a result in which the antenna element 5.6 is moved in the vertical direction (parallel to the cross section) with respect to a long object, and the reflected waves at each angle are synthesized. In the figure, R1 is a reflected wave from the front part of the antenna element 5.6, indicating that the reflection time is fast. [<2 indicates a reflected wave from a portion of the antenna element 5.6 where the tilt angle is large, and the reflection time is slow.

Further, R3 indicates a region where no reflected waves exist beyond a certain range of the tilt angle of the antenna element 5.6. From this detection result example, if the buried object 21 is thick, the hyperbolic arc connecting the wave front values of each reflected wave becomes large, and conversely, if the buried object 21 is thin, the arc becomes small, so the diameter of the buried object 21 is You can know the size of

Next, FIG. 6(B) shows a result of moving the antenna element 5.6 in the left-right direction (longitudinal direction) with respect to the same long object as above, and synthesizing the reflected waves at each angle. In this case, antenna element 5.6 is shown as R4 in the same figure.
Reflected waves still exist even if the tilt angle of is large. From the presence of this reflected wave, it is identified that the object is a long object.

On the other hand, for example, in the case of a short object such as a stone that has the same diameter as the communication pipe, the antenna element 5.6 can be moved either vertically or horizontally as shown in FIG. 6 (A). ＞
Since a combination of reflected waves such as this is obtained, it is possible to identify a short object and distinguish it from a long object such as a communication pipe.

Therefore, it is accurately determined whether the detected buried object 21 is a short object that can be propelled as it is or a long object that cannot be propelled.

In such a buried object detection function, the electromagnetic waves emitted from the transmitting antenna element 5 and the electromagnetic waves slightly reflected on both the inner and outer surfaces of the front plate 3 are absorbed by the radio wave absorber 7 into the transmitting circuit 11 and the receiving circuit 12. This prevents the signal from entering as noise.

In the above embodiment, separate antenna elements were provided for transmission and reception, but by using one antenna element for both functions and providing a transmission/reception switching section, the same effect as in the above embodiment can be achieved. effect can be obtained.

Next, FIGS. 7 to 9 show a second embodiment of the present invention. This embodiment, like the first embodiment, is applied to a propulsion machine, and the front part of the antenna element is made perpendicular to the traveling direction of the propulsion machine, and the antenna element is rotated.

In addition, in FIG. 7 and the drawings showing each embodiment described later, the same or equivalent members and parts in FIG. 1 and FIG. omitted.

In this embodiment, a cylinder 23 is installed inside the steel propulsion tube 1.
is rotatably mounted, and the radio wave absorber 7 is attached to this cylinder 23. The transmitting antenna element 5 and the receiving antenna element 6 are attached to the front surface of the radio wave absorber 7.

The antenna element 5.6 is rotated by a gear carved into the inner circumferential surface of the cylinder 23, and an antenna rotation gear 24 that meshes with this gear, which is rotated by the drive motor 10 via a rotation shaft 25. It will be done. An O-ring 26 is attached to the rotating shaft 25 in order to maintain airtightness behind the mounting plate 9.

Next, the obstacle detection function will be explained using FIGS. 8 and 9.

FIG. 8 shows the received waveform observed when the antenna element 5.6 is rotated. In the waveform diagram, Pl goes around directly from the transmitting/receiving antenna element 5 to the receiving antenna element 6. This shows the peak of the electromagnetic wave, and R2 shows the r-k due to the reflected radio wave from the 75 mm diameter pipe which is the buried object 21. P3 is the peak value when the antenna element 5.6 is rotated 180°,
It was difficult to identify the buried object 21 based only on the peak value P2, but when the antenna element 5.6 was continuously rotated from 0° to 180°, the peak value P3 was confirmed due to the polarization characteristics of the antenna. The buried object 21 is reliably detected.

FIG. 9 shows the received voltage ΔP2("P3-") from the buried object 21.
P2 ) and the rotation angle θ of the antenna element 5.6. In the case of a long and narrow buried object 21 such as a cable or conduit, when the antenna element 5.6 is perpendicular to the buried object 21 (θ-〇° or 180"), the polarization plane becomes parallel to the buried object 21, so the received voltage P2 is small.The antenna element 5.6 rotates to be parallel to the buried object 21 (
When θ=90°), the plane of polarization crosses the buried object 21, so the received voltage P3 increases. That is, in the case of a long and narrow buried object 21 such as a cable or conduit, the difference in received voltage Δ
P2-P3 P2 occurs. In the case of a short object such as a rock, the difference ΔP2 in received voltage due to rotation of the antenna element 5.6 does not occur.

In this way, by rotating the antenna element 5.6, it is possible to detect short objects (propellable) and long objects (impossible) that cannot be distinguished by observation in one direction.
1 size, installation status, etc. can be observed in more detail.

FIG. 10 shows a third embodiment of the invention.

This embodiment is similar to the second embodiment in that the antenna element 5.6 is rotated, but the antenna element 5.6 is rotated along with the front plate 3 in the traveling direction of the propulsion machine. It is tilted at the required angle.

In this embodiment, when the antenna element 5.6 is rotated, the direction of transmitting and receiving electromagnetic waves is varied over a wide angle corresponding to the set angle, so it is possible to detect buried objects 21 and detect short objects. This further improves the ability to determine whether the object is long or long.

FIG. 11 shows a fourth embodiment of the invention.

In this embodiment, the antenna element is rotated by utilizing the viscosity of the soil passing near the antenna installation part when the civil engineering machine is propelled, without incorporating a driving means for the antenna element in the civil engineering machine. This is how it was done.

In FIG. 11, reference numeral 27 denotes a blade for rotating the tip portion, which is provided on the circumferential surface of the tip portion 2 in the shape of a propeller.

Reference numeral 28 denotes a rotation shaft of the tip end, 29 a bearing, and 30 a connector for the rotation shaft to prevent the cord 15 from being twisted during rotation.

When the tip rotating blade 27 receives a reaction from the soil during the propulsion of the civil engineering machine, the antenna element 5.6 rotates due to the action of the tip rotating wheel 28 and the bearing 29. Almost the same as in the third embodiment, the function of detecting the buried object 21 and the function of determining whether the buried object 21 is a short object or a long object can be obtained.

FIG. 12 does not show the fifth embodiment of the present invention.

This embodiment is applied to a civil engineering machine having a rotary cutter, and the antenna element is rotated together with the rotary cutter.

In Fig. 12, 32 is a rotary cutter, 33 is a cutter tooth, 34
is a rotary cutter drive device. A front plate 3 made of ceramics or reinforced plastic is attached to the front part of the rotary cutter 32.
is attached, and an antenna element 5.6 is arranged on the back side of this front plate 3.

When the rotary cutter 32 is driven and rotated by the rotary cutter drive device 34 and the civil engineering machine moves forward to excavate the soil, the antenna element 5.6 rotates accordingly, and the antenna element 5.6 rotates as in the fourth embodiment. Similarly, the function of detecting the buried object 21 and the function of determining whether the buried object 21 is a short object or a long object can be obtained.

FIG. 13 shows a sixth embodiment of the invention.

This embodiment, like the fifth embodiment, is applied to a civil engineering machine having a rotary cutter.
The antenna element is attached to the inside of the cutter teeth of the rotary cutter and is rotated together with the rotary cutter.

In FIG. 13, 35 is a cutter tooth, and this cutter tooth 35
Inside the transmitting and receiving antenna elements 5.
6 are installed respectively. The cutter teeth 35 are made of the same material as the front plate shown in FIG. 12 in order to efficiently pass electromagnetic waves for transmission and reception, and have the same compressive strength and wear strength as the other cutter teeth 33. It is formed to have an appropriate thickness so as to have the following properties.

The function of detecting the buried object 21 and the function of determining whether the buried object 21 is a short object or a long object are substantially the same as those of the fifth embodiment.

FIG. 14 shows a seventh embodiment of the invention.

This embodiment is also applied to a civil engineering machine having a rotary cutter, but antenna elements 5.6 for transmitting and receiving are provided on the side surface of the tip of the main body behind the rotary cutter 32.

In FIG. 14, reference numeral 37 denotes an antenna movement control section that pushes out or retracts the transmitting and receiving antenna elements 5.6 in a vertical direction with respect to the direction of movement of the main body. When the antenna element 5.6 is pushed out by the drive of the antenna movement control section 37, the rotary cutter 32
The area for transmitting and receiving electromagnetic waves from the antenna element 5.6 can be increased relative to the buried object 21 existing in front of the tlI object 21, and as a result, the sensitivity of the reflected signal from the tlI object 21 can be increased. In addition, this deployment configuration of the antenna element 5.6 allows the use of a larger antenna element 5.6 than that shown in FIGS. 12 and 13, so that the frequency range is low and the input Observation is possible using electromagnetic waves with high output strength.

Note that the function of detecting the buried object 21 and the function of determining whether the buried object 21 is a short object or a long object are as described in the fifth section.
This is substantially the same as that of the embodiment and the sixth embodiment.

[Effects of the Invention] As explained above, according to the present invention, the front member of the tip of the civil engineering machine that comes into contact with the soil is made of a non-metallic material, so that its relative permittivity is approximately equal to the relative permittivity of the soil. The electromagnetic waves for transmission and reception can efficiently pass through the front member and the contact surface between the outer surface of the front member and the soil, improving the buried object detection function. According to
Since the antenna is tilted or rotated to the left and right under -F to change the direction of transmitting and receiving radio waves, it is possible to determine whether the detected buried object is short or long and to identify it as an obstruction. This has the effect of being able to accurately detect.

Further, the back surface of the front member is recessed in a spherical shape, and the front part of the antenna has a convex surface made of the same material as the front member and corresponding to the spherical recess, and is closely attached to the recess. According to the embodiment in which a sliding member is attached, in addition to the above-mentioned common effects, electromagnetic waves for transmitting and receiving can pass through the front member more efficiently, further enhancing the buried object detection function, etc. This has the effect of being able to.

[Brief explanation of the drawing]

1 to 6 show a first embodiment of the obstruction detection device for a civil engineering machine according to the present invention. 3 is a sectional view taken along the line A-A in FIG. 2, FIG. 4 is a sectional view 8-8JI in FIG. 2, and FIG. 5 is a waveform showing an example of the waveform of reflected radio waves from buried objects. 6 is a waveform diagram showing an example of the composite waveform of the anti-l1 FII wave when the antenna element is moved in the vertical and horizontal directions with respect to the propulsion direction, and FIGS. Examples are shown. Figure 7 is a longitudinal cross-sectional view of the tip of a civil engineering machine, Figure 8 is a waveform diagram showing an example of the waveform of reflected radio waves from a buried object, and Figure 9 is a diagram showing the rotation angle of the antenna element and the buried object. FIG. 10 is a vertical sectional view of the tip of a civil engineering machine showing a third embodiment of the present invention, and FIG. 11 is a civil engineering machine showing a fourth embodiment of the present invention. FIG. 12 is a longitudinal sectional view of the tip of a civil engineering machine showing a fifth embodiment of the invention, and FIG. 13 is a longitudinal sectional view of the tip of a civil engineering machine showing a sixth embodiment of the invention. FIG. 14 is a longitudinal sectional view of the tip of a civil engineering machine showing a seventh embodiment of the present invention. 2: Tip part, 3: Front plate (front member), 4: Grinding plate (grinding member), 5: Transmission antenna element, 6: Receiving antenna element, 10: Drive motor, 11: Transmission circuit, 12 : receiving circuit, 13: worm gear mechanism, 14: bevel gear mechanism,
20: Control processing unit, 23 Nigilinda, 24: Antenna rotation gear, 25: Rotation shaft. Agent Patent Attorney Yasuo Miyoshi Figure 3 Figure 4 Figure 1 Figure 2 Time until reception (nsec) Figure 5 Swing angle of antenna element (θ) Swing angle of antenna element (θ) 6th Figure (A) Figure 6 (B) Antenna rotation angle θ (bars Figure 9 Figure 8 Figure 11 Figure 13

Claims (4)

[Claims] (1) A front member made of a non-metallic material that has the required strength and is attached to the tip of a civil engineering machine that propels or excavates underground, and is installed on the back side of the front member to detect buried objects through the front member. a transmitting and receiving antenna for transmitting and receiving radio waves; a driving means for tilting or rotating the antenna vertically and horizontally to vary the transmitting and receiving direction of the radio wave; Obstacle for civil engineering machinery characterized by having a transmitting and receiving circuit that feeds transmitted power between a reliable and receiving antenna and receives received power based on reflected radio waves from buried objects. Detection device. (2) The back surface of the front member is recessed in a spherical shape, and the front part of the antenna has a convex surface made of the same material as the front member and corresponding to the spherical recess. 2. The obstacle detection device for a civil engineering machine according to claim 1, further comprising a sliding member that comes into close contact with the obstacle detecting device. (3) The antenna is disposed in a direction perpendicular to the direction of movement of the civil engineering machine or at a required angle of inclination, and the driving means continuously and repeatedly rotates the antenna by half a turn or rotates it. An obstacle detection device for a civil engineering machine according to claim 1. (4) The obstacle detection device for a civil engineering machine according to claim 1, wherein the driving means starts operating based on a buried object detection signal received by the receiving circuit.