Measurement apparatus

Abstract

To improve the accuracy of a measuring device for evaluating the state of the ground.SOLUTION: The measurement device includes a frame, a plurality of wheels attached to the frame, a radiation source that emits radiation, a detector that detects the number of radiation scattered and returned from the ground, a lifting mechanism that is mounted on the frame and changes the height at which the radiation source and the detector are supported, and a control device that is mounted on the frame, controls the operation of the wheels, causes the lifting mechanism to change the height at which the radiation source and the detector are supported, and causes the radiation source and the detector to be in contact with the ground.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a measuring device for evaluating the condition of ground such as compacted ground and pavement. [Background technology]

[0002] In quality control of compacted ground, for example, density is checked. A measuring device that measures density while traveling over a predetermined area of ​​ground has been proposed (Patent Document 1). The measuring device includes a housing, multiple wheels attached to the housing, a radiation source that irradiates the ground with radiation, a detector that detects the amount of radiation reflected by the ground, a position detection unit that detects the position of the measuring device, and a control unit that controls the wheels so that the measuring device travels within a predetermined area that is divided into multiple regions. In this document, the radiation source and detector are supported at a distance from the ground, and values ​​such as the water content calculated based on the detected radiation are corrected according to the distance from the detector to the ground. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2023-95757 Summary of the Invention [Problem to be solved by the invention]

[0004] When evaluating compacted ground as well as roads paved with asphalt or concrete using the RI (Radio Isotope) method, the distance between the detector and the ground is used as the basis for the evaluation. This makes it difficult to make corrections based on the above, and it is difficult to improve the accuracy of the output values.

[0005] The present invention aims to improve the accuracy of measurement devices for assessing ground conditions. [Means for solving the problem]

[0006] In order to solve the above problems, the following measures are adopted. (Aspect 1) The frame and a plurality of wheels attached to the frame; a radiation source that emits radiation; a detector for detecting the amount of said radiation that is scattered by the ground and returned; an elevating mechanism mounted on the frame for changing the height at which the radiation source and the detector are supported; a control device mounted on the frame, which controls the operation of the wheels, and causes the lifting mechanism to change the height at which the radiation source and the detector are supported, and causes the detector to detect the number of radiation beams while the radiation source and the detector are in contact with the ground; A measuring device comprising: (Aspect 2) In the measurement device of aspect 1, a positioning device for detecting a position where the measuring device is located; The control device may move the measurement device to a predetermined measurement point based on the position detected by the positioning device, and cause the detector to detect the amount of radiation at the measurement point. (Aspect 3) In the measurement device of aspect 1 or 2, The lifting mechanism may be a linear actuator that converts the rotational motion of a motor into linear motion, thereby expanding and contracting to change the height at which the radiation source and the detector are supported. (Aspect 4) In the measurement device according to any one of aspects 1 to 3, The control device may calculate an index value for evaluating the condition of the ground based on the number of radiations detected by the detector. (Aspect 5) In the measurement device according to any one of aspects 1 to 4, the radiation is gamma radiation; The index value may be the density of asphalt or concrete paving the ground, or the wet density of the ground. (Aspect 6) In the measurement device according to any one of aspects 1 to 4, the radiation is a neutron beam, The index value may be the moisture content of the ground.

[0007] The contents of the means for solving the problem can be combined as much as possible without departing from the problem and technical idea of ​​the present invention. Furthermore, the contents of the means for solving the problem can be provided as a device such as a computer or a system including multiple devices, a method executed by a computer, or a program executed by a computer. The program can also be executed over a network. A recording medium storing the program may also be provided. [Effects of the Invention]

[0008] According to the present invention, the accuracy of a measuring device for evaluating the condition of the ground can be improved. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram illustrating an example of a measurement system. [Figure 2] FIG. 2 is a schematic side view showing an example of the configuration of the measurement device. [Figure 3] FIG. 3 is a block diagram mainly showing an example of electrical connections in the measurement device. [Figure 4] FIG. 4 is a processing flow diagram showing an example of the route information creation processing. [Figure 5] FIG. 5 is a diagram for explaining the route information. [Figure 6] FIG. 6 is a processing flow diagram showing an example of the measurement processing. [Figure 7] FIG. 7 is a graph showing the verification results of the asphalt density calculated by the measuring device according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment will be described with reference to the drawings. The configurations shown in the embodiments are merely examples, and the present invention is not limited to the specific configurations of the embodiments. In other words, when implementing the present invention, various configurations can be appropriately adopted within the scope of the objectives and technical ideas of the present invention.

[0011] <Configuration example> FIG. 1 is a diagram showing an example of a measurement system. The measurement system 100 includes a measurement device 1, a server 2, and terminals 3 (3A, 3B). These components are connected to each other via a network 4 so that they can communicate with each other. The measurement device 1 travels over ground such as compacted ground or an asphalt-paved road, and outputs index values ​​for evaluating the condition of the ground. The ground to be evaluated is, for example, some kind of land, such as land for constructing a road, but is not particularly limited to this. The index values ​​can also be used to evaluate, for example, the density of paving asphalt or concrete, It may be the water content or water content ratio of the ground, or the wet density of the ground, or the like.

[0012] The server 2 is a computer connected to the network 4, and acquires and stores location information and index values ​​for evaluating the condition of that location from the measurement device 1. The server 2 may also create route information for the measurement device 1 to automatically travel and measure. The server 2 may also be a cloud system that uses ICT (Information and Communication Technology) to perform quality control in various earthwork processes.

[0013] The terminal 3 is a device used by a user, such as a PC (Personal Computer), a tablet, etc. The terminal 3 may be a laptop, smartphone, or other computer, or may be a wireless controller for directly transmitting wireless signals to the measurement device 1. The terminal 3 may receive input from the user of the range to be measured by the measurement device 1 and transmit it to the server 2, and the server 2 may create the above-mentioned route information. Note that the terminal 3 may also receive input from the user of, for example, the range to be measured by the measurement device 1 and create the above-mentioned route information. The terminal 3 may also acquire and display information held by the server 2 based on the user's operation.

[0014] The network 4 includes, for example, an IP (Internet Protocol) network. Devices connected to the network 4 can communicate based on a predetermined communication protocol. Part of the network 4 may be a telephone network (fixed telephone network or mobile communication network), an ad hoc network, an intranet, a VPN (Virtual Private Network), a LA (Landline Telephone Network), or a similar network. N (Local Area Network), Wireless LAN, WAN (Wide Area Network) ), or the Internet.

[0015] FIG. 2 is a schematic side view showing an example of the configuration of a measurement device. FIG. 3 is a block diagram mainly showing an example of the electrical connections of the measurement device. In FIG. 2, for convenience, the direction from left to right in the figure is defined as the x direction, the direction from the front (near side) to the back (rear side) in the figure is defined as the y direction, and the direction from bottom to top in the figure is defined as the z direction. The measurement device 1 travels over ground 200, such as compacted ground or an asphalt-paved road, and performs measurements to evaluate the condition of the ground 200. The ground 200 on which the measurement device 1 travels is a surface that is approximately parallel to the xy plane.

[0016] The measurement device 1 includes a frame 11, wheels 12, a lifting mechanism 13, a holding member 14, a radiation source 15, a detector 16, a positioning device 17, and a control device 18. The measurement device 1 is equipped with a power supply (battery). The power supply supplies power to the detector 16, the positioning device 17, the control device 18, and other devices such as motors.

[0017] The frame 11 is the skeletal structure of the measurement device 1, formed by combining metal beams, for example, but there are no particular restrictions on the material or shape. The wheels 12 are attached to the frame 11 and rotate around the axles to move the measurement device 1. The measurement device 1 has three or more wheels, and the multiple wheels 12 support the frame 11 above the ground. At least one of the front and rear wheels is attached so that its steering angle can be changed.

[0018] The lifting mechanism 13 changes the height of the radiation source 15 and the detector 16. Specifically, the lifting mechanism 13 is, for example, a linear actuator (cylinder actuator) and includes a motor 131 and an extension / contraction unit 132. The rotational motion of the motor 131 is converted into the linear motion of the extension / contraction unit 132, which is formed by, for example, a spindle and a cylinder. That is, one end of the extension / contraction unit 132 is connected to the motor 131, and the length to the other end is changeable. The extension / contraction unit 132 in FIG. 2 extends and contracts in the vertical direction (z direction), changing the height of the holding member 14 connected to its lower end. The holding member 14 is connected to the other end of the extension / contraction unit 132 and holds the radiation source 15 and the detector 16. The radiation source 15 and the detector 16 may constitute an integrated instrument unit. Furthermore, the holding member 14 may be a unit that includes the radiation source 15 and the detector 16, or an instrument unit including these. The holding member 14 may be a member for holding the cot by suspending it vertically below the holding member 14, or a member for placing it vertically above the cot.

[0019] The radiation source 15 is a radiation source (radioisotope) that irradiates (emits) radiation for measuring the condition of the ground. The radiation source 15 includes at least one of a radiation source that irradiates neutron rays and a radiation source that irradiates gamma rays. The radiation source 15 may be suspended from the holding member 14 and irradiate radiation toward the ground. Furthermore, when the radiation source 15 is placed on the holding member 14, it may irradiate radiation toward the ground from, for example, an opening provided in the holding member 14.

[0020] The detector 16 detects radiation emitted from the radiation source 15 and scattered by the ground. In this embodiment, the term "ground" includes the underground near the surface of the earth, and if the ground is paved with asphalt or the like, also includes the surface layer and base layer. The detector 16, for example, counts the number of radiation rays incident on the detector 16. The detector 16 may be suspended from the holding member 14 so that the sensor portion that detects radiation faces the ground. When the detector 16 is placed on the holding member 14, the sensor portion faces, for example, toward an opening of the holding member 14. The detector 16 is capable of detecting radiation irradiated by the radiation source 15 (in this embodiment, at least one of neutron rays and gamma rays). The number of radiation rays (count value) detected by the detector 16 is converted into an index value for evaluating the condition of the ground. When evaluating the density of paving asphalt or concrete, the count rate of gamma rays can be converted into density using a pre-created calibration formula. When evaluating ground after compaction, the water content or water content ratio of the ground may be calculated using the count value of neutron rays, or the wet density of the ground may be calculated using the count value of gamma rays.

[0021] The positioning device 17 includes a GNSS antenna that receives radio waves (positioning signals) transmitted from positioning satellites, which are satellites of the GNSS (Global Navigation Satellite System). Based on the positioning signals, the positioning device 17 (in other words, the measurement device 1) outputs information indicating the location of the positioning device 17. The location information is expressed, for example, by latitude, longitude, and altitude. The positioning device 17 repeats outputting the location information at a predetermined interval. Note that the positioning device 17 may detect the location of the measurement device 1 using a positioning system other than the GNSS, such as a beacon.

[0022] 3, the control device 18 is a computer, and includes an arithmetic unit 181, a storage device 182, an input / output interface (IF) 183, and a communication interface (IF) 184. The arithmetic unit 181 includes, for example, a CPU (Central Processing Unit), Processors such as MCU (Micro Controller Unit), MPU (Micro Processing Unit), DSP (Digital Signal Processor), FPGA (Field Programmable Gate Array), These include ASICs (Application Specific ICs), ASSPs (Application Specific Standard Products), etc. The arithmetic unit 181 performs the processes described in this embodiment by, for example, executing programs.

[0023] The storage device 182 is a main storage device such as a RAM (Random Access Memory) or a ROM (Read Only Memory), and an auxiliary storage device (secondary storage device) such as an HDD (Hard-disk Drive), an SSD (Solid State Drive), or a flash memory. The main storage device temporarily stores programs read by the arithmetic device 181 and secures a working area for the arithmetic device 181. The auxiliary storage device stores programs executed by the arithmetic device 181 and other data.

[0024] The input / output IF 183 is an interface for transmitting signals between the control device 18 and the detector 16, the positioning device 17, each motor, etc., and may include, for example, a predetermined connector or cable.

[0025] The communication IF 184 is, for example, a communication module for wireless communication with a mobile phone base station or a wireless LAN (Local Area Network) access point, or a communication module for configuring a two-way communication (telemetry) system with the terminal 3, and communicates based on a predetermined protocol.

[0026] The arithmetic device 181 acquires position information from the positioning device 17 via the input / output IF 183 and stores it in the storage device 182. The arithmetic device 181 also controls the operation of the measurement device 1. The control device 18 may autonomously cause the measurement device 1 to travel, or may receive a signal from a wireless controller (terminal 3) via the communication IF 184 and cause the measurement device 1 to travel in accordance with the received signal. When causing the measurement device 1 to travel autonomously, for example, information on the travel route and measurement points created by the arithmetic device 181 or the server 2 may be stored in advance in the storage device 182. The arithmetic device 181 controls the travel motor 121 and the steering motor 122 connected to the wheels 12 based on the information on the travel route and measurement points and the position information, thereby controlling the travel speed and direction of the measurement device 1. The arithmetic device 181 also acquires radiation detection results from the detector 16, calculates an index value corresponding to the count value, and stores the index value in the storage device 182. The index value is, for example, an estimated value representing the water content of the ground, the water content ratio of the ground, or the wet density of the ground. The calculation device 181 may also transmit the index value to the server 2 or the terminal 3 via the communication IF 184.

[0027] The server 2 and the terminal 3 are also computers, each equipped with a computing device, a storage device, and a communication IF. The terminal 3 further includes a display, a touch panel stacked on the display, a keyboard, a pointing device, and other user interfaces.

[0028] <Measurement point setting process> FIG. 4 is a process flow diagram showing an example of the operation of the system. For example, terminal 3 accepts the specification of a measurement range on a map based on a user's operation and transmits it to server 2 (FIG. 4: S1). FIG. 5 is a diagram for explaining route information. The measurement range may be input, for example, by defining the vertical and horizontal lengths of a rectangle, or by defining the perimeter of the area using the latitudes and longitudes of three or more points. For example, when the area shown by the dashed-line rectangle in FIG. 5 is specified by the user, the latitudes and longitudes of points 201-204 corresponding to the four corners, or the relative coordinates of points 201-204, are transmitted from terminal 3 to server 2.

[0029] Meanwhile, the server 2 receives information indicating the measurement range (S2 in FIG. 4) and sets a driving route and measurement points (also referred to as "route information") within the measurement range (S3 in FIG. 4). In this step, a driving route 205 shown by a solid line in FIG. 5 and multiple measurement points 206 shown by circles in FIG. 5 are determined. The driving route 205 is created, for example, by arranging multiple straight driving lines parallel to each other at predetermined intervals and connecting the ends of adjacent driving lines so that the driving route 205 can be drawn in one continuous stroke. The orientation of the driving lines within the measurement range may be determined by, for example, receiving input from the user in S1 regarding the inclination relative to the north-south or east-west direction, or by setting the driving lines parallel to the long sides of the measurement range. The measurement points are arranged at predetermined intervals on each driving line. It is sufficient that the measurement points are set evenly within the measurement range, and the route information is not limited to that shown in FIG. 5. The route information may be defined using absolute coordinates such as latitude and longitude, or may be defined using relative coordinates.

[0030] The server 2 also transmits the route information to the measuring device 1 (FIG. 4: S4). Meanwhile, the calculation device 181 of the measuring device 1 receives the route information via the communication IF 184 and stores it in the storage device 182 (FIG. 4: S5).

[0031] <Measurement processing> 6 is a process flow diagram showing an example of a process executed by the measuring device 1. The measuring device 1 travels on the ground based on route information while measuring its own position, etc., and calculates an index value for evaluating the wet density, moisture content, or moisture ratio at a predetermined measurement point.

[0032] The arithmetic device 181 of the measuring device 1 reads out the route information from the storage device 182 (FIG. 6: S11). The arithmetic device 181 also controls the travel motor 121 and the steering motor 122 to cause the measuring device 1 to travel along the travel route to the next measurement point (FIG. 6: S12). The arithmetic device 181 also acquires position information from the positioning device 17 at a predetermined cycle, and causes the measuring device 1 to travel autonomously based on the position information and route information.

[0033] After S12, the arithmetic device 181 controls the lifting mechanism 13 to lower the radiation source 15 and the detector 16 (FIG. 6: S13). In this step, the arithmetic device 181 rotates the motor 131 to extend the extension part 132 until the radiation source 15 and the detector 16 come into contact with or approach the ground. The arithmetic device 181 may extend or retract the extension part 132 by a predetermined length, or may detect that the radiation source 15 and the detector 16, or an instrument unit including these, or the holding member 14 has come into contact with the ground based on the torque (current) of the motor 131 or the number of rotations per unit time of the motor 131.

[0034] After S13, the detector 16 of the measuring device 1 counts and outputs the number of radiation particles (count number) that have been scattered inside the ground and returned (FIG. 6: S14). The radiation is emitted from the radiation source 15, scattered inside the ground, and then transmitted to the ground surface. The arithmetic unit 181 of the control device 18 acquires the count value of the radiation particles output by the detector 16 and stores it in the storage device 182 in association with the position information. The detector 16 performs measurements at a predetermined sampling frequency (e.g., 1 Hz). The count value of the number of radiation particles may be an integrated value per unit time (e.g., 1 second). The control device 18 of the measuring device 1 stores the count value detected by the detector 16 in the storage device 182 in association with the information of the measurement point.

[0035] The computing device 181 may store the water content, water content ratio, or wet density of the ground, calculated from the count value by a well-known method, in the storage device 182, instead of or in addition to the count value detected by the detector 16. The computing device 181 may also transmit the count value, etc. to the server 2 or the terminal 3 via the communication IF 184. The server 2 may also use the count value to calculate the water content, water content ratio, or wet density of the ground.

[0036] After S14, the arithmetic device 181 controls the lifting mechanism 13 to raise the radiation source 15 and the detector 16 (FIG. 6: S15). In this step, the arithmetic device 181 rotates the motor 131, and the extension / contraction part 132 of the holding member 14 that holds the radiation source 15 and the detector 16 is contracted to a predetermined height.

[0037] After S15, the calculation device 181 determines whether there are any unprocessed measurement points in the route information (S16 in FIG. 6). If there are any unprocessed measurement points (YES in S16), the process returns to S12 and the measurement device 1 travels to the next measurement point. On the other hand, if it is determined that there are no unprocessed measurement points (NO in S16), the measurement process in FIG. 6 ends. Note that data may be transmitted from the measurement device 1 to the server 2 after each measurement in S16, or may be transmitted all at once after measurements have been completed for all planned measurement points.

[0038] <Effects> In this embodiment, the measurement is performed by placing the instrument in close contact with the ground, which improves the accuracy of the measured values. Figure 7 is a graph showing the verification results of asphalt density calculated by the measuring device according to the embodiment. The graph in Figure 7 has the vertical axis representing density (g / cm 3 ) and The horizontal axis represents the identification information of the measurement point. The data points plotted as circles represent the asphalt density output by the measurement device 1, and the data points plotted as squares represent the asphalt density measured by core sampling. Measurement by core sampling is performed after the construction of the asphalt pavement is completed by drilling a cylindrical hole (core extraction) in the asphalt with a core cutter and measuring the density. As shown in FIG. 7 , the accuracy of the asphalt density calculated by the measurement device 1 was good. According to the embodiment, density measurement can be performed nondestructively. In particular, asphalt and concrete (mainly dam concrete) have many voids (unevenness) on the surface, making it difficult to accurately estimate wet density by correcting the distance between the ground and a detector installed at a distance from the ground. In the embodiment, the measurement is performed by placing the instrument in close contact with the ground, which improves the accuracy of the output value compared to, for example, correcting measurements taken by an instrument located at a distance from the ground based on the distance between the instrument and the ground. Furthermore, when determining the moisture content, the accuracy is higher when the detector is placed in close contact with the ground as in the embodiment, rather than when correction is made based on distance.

[0039] <Other> The above-described embodiment is merely an example, and the present invention is not limited to the above-described configuration. For example, the configuration of the lifting mechanism 13 is not limited as long as it can bring the holding member 14, which holds the radiation source 15 and the detector 16, into contact with the ground or move it upwardly away from the ground. In other words, the lifting mechanism 13 is not limited to a linear actuator, and may be one that uses a crank mechanism, etc.

[0040] The measurement device 1 may also be a drone such as a multicopter. In this case, for example, the rotor functions as the lifting mechanism 13, and the drone lands at the measurement point and brings the radiation source 15 and the detector 16, or an instrument unit including these, into contact with the ground. The drone may fly autonomously based on the route information described above.

[0041] Furthermore, instead of the detector 16 that detects radiation emitted from the radiation source 15 and scattered by the ground, an electromagnetic density meter that measures the density of the ground based on the dielectric constant of the ground measured using electromagnetic waves may be installed. The accuracy of the electromagnetic density meter can also be improved by making the electromagnetic wave transmitter and receiver contact the ground and performing measurements.

[0042] The present invention also covers a computer program for executing the above-described process and a computer-readable recording medium having the program recorded thereon. The recording medium having the program recorded thereon enables the above-described process by causing a computer to execute the program.

[0043] A computer-readable recording medium is a recording medium that stores information such as data and programs electrically, magnetically, optically, mechanically, or chemically and can be read by a computer. Among such recording media, those that can be removed from a computer include flexible disks, magneto-optical disks, optical disks, magnetic tapes, memory cards, etc. Furthermore, recording media that are fixed to a computer include HDDs, SSDs, ROMs, etc. [Explanation of symbols]

[0044] 100: Measurement system 1: measuring device, 11: frame, 12: wheels, 121: travel motor, 122: steering motor, 13: lifting mechanism, 131: motor, 132: telescopic section, 14: holding member, 15: radiation source, 16: detector, 17: positioning device, 18: control device, 181: computing device, 182: storage device, 183: input / output interface, 184, communication interface 2: Server 3: Terminal 4: Network

Claims

1. The frame and a plurality of wheels attached to the frame; a measuring device including a radiation source that emits radiation and a detector that detects the number of the radiation scattered on the ground and returned, or a transmitter that transmits predetermined electromagnetic waves and a receiver that receives the electromagnetic waves; an elevating mechanism mounted on the frame for changing the height at which the measuring device is supported; a control device mounted on the frame, which controls the operation of the wheels, and causes the lifting mechanism to change the height at which the measuring device is supported and to perform the detection while the measuring device is in contact with the ground; A measuring device comprising:

2. a positioning device for detecting a position where the measuring device is located; The control device moves the measurement device to a predetermined measurement point based on the position detected by the positioning device, and performs the measurement using the measuring instrument at the measurement point. The measurement device according to claim 1 .

3. The lifting mechanism is a linear actuator that converts the rotational motion of a motor into linear motion, thereby expanding and contracting to change the height at which the measuring device is supported. The measuring device according to claim 1 or 2.

4. the measuring device includes the radiation source and the detector; The control device calculates an index value for evaluating the state of the ground based on the number of the radiation detected by the detector. The measuring device according to claim 1 or 2.

5. the radiation is gamma radiation; The index value is the density of asphalt or concrete paving the ground, or the wet density of the ground. The measurement device according to claim 4.

6. the radiation is a neutron beam, The index value is the water content of the ground. The measurement device according to claim 4.

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