Gas detecting system and gas detecting method

Abstract

Provided is a technique capable of efficiently detecting chemical substances with reduced power consumption. This gas detecting system comprises: a ground-level moving body that can move along the ground; one or more flying bodies that are mounted on the ground-level moving body and that can float in the air; and a sensor that is provided on at least the one or more flying bodies to detect a chemical substance in a gas. The gas detecting system performs detection using the sensor in a first mode in which the one or more flying bodies are mounted on the ground-level moving body, and then transitions to a second mode in which the one or more flying bodies are allowed to float from the ground-level moving body, and performs detection using the sensor.

Description

Gas detection system and gas detection method

[0001] The present disclosure relates to gas detection systems and methods.

[0002] Conventionally, when a gas (chemical substance) leak occurs (or is suspected) in a plant or the like, a large number of workers carrying gas sensors search for the location of the gas leak and repair the detected location. Such a gas leak search takes a lot of time and places a heavy burden on the workers. Furthermore, the location of the gas leak may be located in a high place that is difficult for workers to reach.

[0003] Therefore, development of systems for detecting the state of gas in a space is progressing. For example, Patent Literature 1 discloses a system for creating a three-dimensional gas map by using an airborne flying object (remote vehicle) that can move in the air.

[0004] Special Publication No. 2018-523835

[0005] If the system described above were configured so that the aircraft moves evenly throughout a set three-dimensional space to detect gases (chemical substances), the aircraft's power consumption would increase. In some cases, the aircraft's power would run out while detecting gas, causing the inconvenience of having to interrupt the search midway.

[0006] The present disclosure provides a technology that can efficiently detect chemical substances while reducing power consumption.

[0007] According to one aspect of the present disclosure, there is provided a gas detection system comprising a ground vehicle capable of moving on the ground, one or more flying bodies mounted on the ground vehicle and capable of floating in the air, and a sensor mounted on at least the one or more flying bodies for detecting chemical substances in a gas, wherein the gas detection system performs detection with the sensor in a first form in which the one or more flying bodies are mounted on the ground vehicle, and then transitions to a second form in which the one or more flying bodies are floated from the ground vehicle and performs detection with the sensor.

[0008] According to the above, the gas detection system can efficiently detect chemical substances while reducing power consumption.

[0009] Furthermore, the ground vehicle sets a ground position where the one or more flying bodies will take off based on the concentration of the chemical substance detected by the sensor in the first configuration, and moves to the ground position, and the one or more flying bodies transition to the second configuration at the ground position. By setting a ground position where the one or more flying bodies will transition to the second configuration based on the concentration of the chemical substance detected in the first configuration, the gas detection system can more efficiently search for locations with high concentrations of chemical substances.

[0010] In addition, in the first mode, the ground vehicle executes a first search step of moving within a first area and performing detection with the sensor, and a second search step of setting a second area that is narrower than the first area based on the detection result of the first search step, moving within the second area and performing detection with the sensor to set the ground position. By performing the first search step and the second search step, the gas detection system can efficiently detect chemical substances even in a wide search area, for example.

[0011] The second area is the position in the first area where the concentration of the chemical substance is highest and its surrounding area. By setting the position in the first area where the concentration of the chemical substance detected is highest as the second area, the gas detection system can narrow the second area sufficiently and more accurately search for the position where the concentration of the chemical substance is high.

[0012] Furthermore, the ground position is the position in the second area where the concentration of the chemical substance is the highest. By setting the ground position to the position where the concentration of the chemical substance detected in the second area is the highest, the gas detection system can efficiently search for areas where the concentration of the chemical substance is high when the flying object is lifted.

[0013] The gas detection system is provided with a sensor in each of the one or more air vehicles and the ground moving vehicle, and by providing a sensor in each of the air vehicles and the ground moving vehicle, the gas detection system can appropriately detect gas on the ground and in the air by using each sensor.

[0014] In addition, the ground vehicle detects the concentration of the chemical substance using the sensor while moving in the first configuration, and recognizes the concentration distribution of the chemical substance on the ground. By detecting chemical substances while moving on the ground, the gas detection system can significantly reduce the time required for detection compared to when detection is performed by repeatedly moving and stopping.

[0015] Furthermore, the one or more flying vehicles detect the concentration of the chemical substance with the sensor while moving in the second form, and recognize the concentration distribution of the chemical substance in the air. By detecting chemical substances while moving in the air, the gas detection system can significantly reduce the time required for detection in the air.

[0016] The gas detection system further includes a processing unit that recognizes the specific gravity of the chemical substance relative to the atmosphere and the concentration of the chemical substance based on the detection information detected by the sensor, and sets control details for the ground vehicle and / or the one or more air vehicles. By setting control details based on the specific gravity of the chemical substance, the gas detection system can perform appropriate detection according to the flow of the chemical substance in the air.

[0017] Furthermore, when the processing unit detects the chemical substance having a specific gravity equal to or greater than that of atmosphere in the first mode and the concentration of the chemical substance is equal to or greater than the ground threshold, the processing unit transitions to the second mode and performs detection by the sensor, and when the processing unit does not detect the chemical substance having a specific gravity equal to or greater than that of atmosphere in the first mode or detects the chemical substance having a specific gravity equal to or greater than that of atmosphere and the concentration of the chemical substance is less than the ground threshold, the processing unit transitions to the second mode and performs detection by the sensor after moving the ground vehicle to a set position. This allows the gas detection system to appropriately detect chemical substances having a specific gravity equal to or greater than that of atmosphere both on the ground and in the air.

[0018] Furthermore, at least one of the ground moving body and the one or more flying bodies is equipped with an external sensor that acquires information on terrain and / or objects present in the direction of movement, and when moving in the first form and / or the second form, if an object to be avoided is present in the direction of movement based on detection by the external sensor, the ground moving body avoids the object to be avoided and continues moving. This allows the gas detection system to prevent the ground moving body and the flying body from coming into contact with objects and to stably detect chemical substances.

[0019] Furthermore, the ground vehicle has a power supply unit that supplies power to the one or more flying bodies in at least one of the first and second configurations, thereby preventing the flying body from losing detection midway due to a power shortage during flight.

[0020] In addition, one of the one or more flying vehicles is mounted on the ground vehicle, which allows the gas detection system to narrow down the search for the location of the gas leak by suppressing the disturbance of the gas in the air caused by the flying of many flying vehicles.

[0021] Furthermore, the sensor detects the plurality of types of chemical substances separately, and by detecting the plurality of types of chemical substances separately, the gas detection system can detect a variety of chemical substances, thereby further increasing versatility.

[0022] In addition, at least one of the ground moving body and the one or more air vehicles transmits the information detected by the sensor to the other of the ground moving body and the one or more air vehicles, or transmits the information to an information processing device different from the ground moving body and the one or more air vehicles. The gas detection system can make it easier to understand the state of the chemical substance by aggregating the detection information of the sensors of the ground moving body and the one or more air vehicles.

[0023] According to another aspect of the present disclosure, there is provided a gas detection method for detecting a chemical substance in a gas, the gas detection method including: a ground search step of moving in a first configuration in which a ground vehicle capable of moving on the ground is equipped with one or more flying bodies capable of floating in the air and detecting the chemical substance using sensors provided on at least the one or more flying bodies; and an aerial search step of, after the ground search step, transitioning to a second configuration in which the one or more flying bodies are floated from the ground vehicle and detecting the chemical substance using the sensors. Even in this case, the gas detection method can efficiently detect the state of the chemical substance while reducing power consumption.

[0024] FIG. 5(B) is a plan view illustrating the movement range of the assembly robot in the fine search process. FIG. 6(A) is a block diagram illustrating the processing and judgment of the fine search control unit in the fine search process. FIG. 6(B) is an explanatory diagram illustrating an example of the operation of the assembly robot in the fine search process. FIG. 6(B) is an explanatory diagram illustrating the operation and gas detection in the ascending search process of the gas detection method. FIG. 5(B) is a side view illustrating the overall configuration of the gas detection system in the first embodiment. FIG. 5(A) is a block diagram illustrating the hardware configuration of the ground robot and the drone. FIG. 5(B) is a flowchart illustrating an example of the gas detection method in the second embodiment.

[0025] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals, and redundant explanations may be omitted.

[0026] 1 is a side view showing the overall configuration of a gas detection system 1 according to a first embodiment. The gas detection system 1 according to the embodiment is used in plants, facilities, etc. where there is a possibility of a gas (chemical substance) leak, and includes an assembly robot 10 that automatically searches for (or estimates) the location GL of the gas leak. This assembly robot 10 is configured by combining a ground vehicle and an air vehicle.

[0027] Specifically, the assembly robot 10 includes a ground moving body (hereinafter referred to as a ground robot 20) that can move on the ground in an unmanned state, and one or more air vehicles (hereinafter referred to as drones 40) that can move through the air in an unmanned state. The assembly robot 10 assumes a first form in which the drone 40 is mounted on the ground robot 20. In this first form, the assembly robot 10 moves while carrying the drone 40 and detects gas on the ground. Furthermore, based on information about gas detected on the ground, the assembly robot 10 transitions to a second form in which the drone 40 is lifted from the ground robot 20. In this second form, the drone 40 detects gas in the air while moving through the air.

[0028] The ground robot 20 is configured to automatically move over any area on the ground. The ground robot 20 according to the embodiment uses a small vehicle having a plurality of (e.g., four) wheels 211 as a running unit 21 for moving on the ground. The configuration of the running unit 21 is not particularly limited, and various configurations capable of running on the ground can be adopted. Other examples of the running unit 21 include one having a pair of crawlers (caterpillars) and one having a plurality of legs.

[0029] The ground robot 20 also includes a housing 22 mounted on the traveling unit 21. The housing 22 has a flat upper surface, and the drone 40 is placed and held on this upper surface to achieve a first configuration with the drone 40 mounted thereon. The upper surface of the housing 22 includes an engagement structure 221 for mooring the drone 40. The engagement structure 221 may have an appropriate configuration that can appropriately enable the drone 40 to lift off from the housing 22 and land after lifting. For example, the engagement structure 221 may include multiple locking bodies that receive the drone 40's weight, hook onto multiple legs 411, and hold the drone 40, and release the engagement of each leg 411 when a lift-off trigger is received from the drone 40. The engagement structure 221 may be provided on the drone 40 side, or both the ground robot 20 and the drone 40 may have an appropriate configuration. Alternatively, the housing 22 and the drone 40 may not include the engagement structure 221, and the drone 40 may simply be placed on the upper surface of the housing 22.

[0030] 2 is a block diagram showing the hardware configuration of the ground robot 20 and the drone 40. As shown in Fig. 2, the ground robot 20 has a ground-side control unit 23 inside a housing 22 that automatically drives the traveling unit 21 and controls gas detection on the ground. The ground robot 20 also has a gas sensor 24 that detects gas on the ground, an external sensor 25 that acquires external environmental information, an internal sensor 26 that acquires status information of the ground robot 20, a position sensor 27 that acquires the current position, a power supply unit 28, and a power supply unit 29.

[0031] The ground-side control unit 23 is a computer having one or more processors 231, a memory 232, an input / output interface 233, and a communication interface 234. The one or more processors 231 are one or a combination of a central processing unit (CPU), a graphics processing unit (GPU), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a circuit made up of a plurality of discrete semiconductors, etc. The memory 232 includes a main storage device made up of a semiconductor memory or the like, and an auxiliary storage device made up of a disk, semiconductor memory (flash memory), etc.

[0032] The ground-side control unit 23 controls the operation of the ground robot 20, i.e., the operation of the assembly robot 10 equipped with the drone 40, by having the processor 231 execute a program stored in the memory 232. For example, the ground-side control unit 23 has an autonomous movement control function that automatically moves the ground robot 20 within a search area SA (see FIG. 5(A)) set by an operator. Furthermore, while the ground robot 20 is moving, the ground-side control unit 23 continuously detects gas using the gas sensor 24, recognizes the current position of the ground robot 20, and associates the gas detection information with the current position. Furthermore, the ground-side control unit 23 sets a ground position where the drone 40 is to lift off, and when the drone 40 moves to this ground position, it disengages the engagement structure 221, allowing the drone 40 to lift off.

[0033] The gas sensor 24 detects the state of gas, which is a gaseous chemical substance contained in the atmosphere (or a predetermined gas component) on the ground. The gas sensor 24 may be provided on the side or top surface of the housing 22, and in this embodiment, it is provided forward in the direction of movement of the housing 22. In other words, gas on the ground refers to a chemical substance present at a predetermined height (e.g., in a range of approximately 0 m to 2 m) above the ground. In addition, in this description, "detecting" a gas refers to measuring the gas using a sensor element provided in the gas sensor 24. Meanwhile, in this specification, "detecting" a gas refers to processing information on the gas detected by the gas sensor 24 to obtain target information (a gas concentration distribution map, a gas leak location GL).

[0034] The state of the chemical substance to be detected includes, for example, the type of chemical substance, the concentration of the chemical substance, the amount of components contained in the air, the component ratio, etc. ２ F ４ , C.H. ２ Cl ２ , C.H. ３ OH, C ６ F １４ , C.H. ２ F ２ , CO, C ４ H １０ O, CHClF ２ , HF, HCl, C ２ ClF ３ , C ３ F ６ , C ４ F ８ , C ２ HF ５ , CHF ３ , C ５ F １０ O.C. ３ F ６ O, SO ２ , Cl ２ , N ２ , N.H. ３ , C ２ H ４ , H ２ , He, etc., and the chemical substance may contain one or more of these. ４ , C.H. ３ , C３ H ８ , C ４ H １０ mixed gas), LP gas (C ３ H ８ , C ４ H １０ The chemical substance to be detected is not limited to gas, but may be suspended matter in the air (dust, etc.).

[0035] The gas sensor 24 is preferably a composite gas detector in which multiple sensor elements are arranged to distinguish and detect multiple types of chemical substances. Each of the multiple sensor elements is configured using an appropriate method (such as catalytic combustion, controlled potential electrolysis, galvanic cell, infrared absorption, Raman scattering, electrochemical, or field-effect transistor) capable of detecting the concentration of the target gas. The gas sensor 24 may also be a surface acoustic wave (SAW) sensor. In cases where the type of chemical substance to be detected is known in advance, the gas detection system 1 may employ a gas sensor 24 having a single sensor element corresponding to that chemical substance.

[0036] The external sensor 25 is connected to the ground-side control unit 23, and detects information about the terrain around the ground robot 20 (ground surface conditions such as grooves, holes, bumps, etc., slopes, wet spots, gravel, etc.) and information about objects, and transmits this information to the ground-side control unit 23. Examples of this external sensor 25 include a camera (including a monocular and compound eye), LiDAR, an ultrasonic sensor, a millimeter-wave radar, a distance image sensor, an infrared sensor, etc.

[0037] The internal sensor 26 is connected to the ground control unit 23, detects information such as the current moving speed, direction, and tilt (posture) of the ground robot 20, and transmits the information to the ground control unit 23. Examples of the internal sensor 26 include a speed sensor, a steering angle sensor, an acceleration sensor, and a gyro sensor.

[0038] The position sensor 27 is connected to the ground-side control unit 23, detects the current position of the ground robot 20, and transmits the information to the ground-side control unit 23. Examples of this position sensor 27 include a global positioning satellite system (GNSS) including GPS, a motion sensor, a beacon, etc. The ground-side control unit 23 may compare pre-stored map data with information acquired from the external sensors 25 such as LiDAR and cameras, and determine the position on the map data based on this information.

[0039] The power supply unit 28 can be a well-known secondary battery (e.g., a lead-acid battery, a lithium-ion battery, a nickel-metal hydride battery, or a fuel cell). The ground robot 20 may also use a generator that generates electricity using an internal combustion engine or a solar cell that generates electricity using sunlight. Alternatively, the power supply unit 28 of the ground robot 20 may be connected to an external power source by wire and obtain power from the external power source.

[0040] The power supply unit 29 supplies power to the drone 40 while the drone 40 is mounted on the housing 22. For example, the power supply unit 29 may have a plurality of electrodes (not shown) on the top surface of the housing 22 and supply power to the drone 40 when the legs of the drone 40 come into contact with a pair of the electrodes in the first form. The power supply unit 29 may also be configured to supply power wirelessly to the drone 40 placed on the top surface of the housing 22. Alternatively, the power supply unit 29 may be wired and connected to the drone 40 via a power line (not shown). In this case, the power supply unit 29 may supply power not only in the first form in which the drone 40 is placed on the top surface of the housing 22, but also in the second form in which the drone 40 is airborne.

[0041] 1 , the drone 40 of the gas detection system 1 rises from the ground robot 20 and detects gas at a position higher than the ground robot 20. The drone 40 has a housing 41 and a flight structure 42 provided on the upper part of the housing 41.

[0042] The flight structure 42 includes a connecting part 421 connected to the housing 41, a plurality of arms 422 (four in this embodiment) extending outward from the connecting part 421, and four propeller mechanisms 423 provided at the extending ends of the arms 422. It goes without saying that the number of propeller mechanisms 423 of the flight structure 42 is not particularly limited.

[0043] An electrical component unit is provided inside the connecting portion 421, which supplies appropriate power to the motors (not shown) of the respective propeller mechanisms 423 to independently rotate the respective propeller mechanisms 423. The electrical component unit may include, for example, a DC-DC converter, a distributor, an ESC (Electric Speed ​​Controller), etc.

[0044] The four arms 422 are connected to the side surfaces of the connecting portion 421 and extend at equal intervals (90° intervals) from the connecting portion 421. Electrical wiring (not shown) is provided inside each arm 422, connecting the electrical equipment section to each propeller mechanism 423.

[0045] The four propeller mechanisms 423 have propellers 423p connected to the rotation shafts of the motors. The drone 40 ascends, descends, hoveres, moves horizontally, adjusts its attitude, and so on by generating a pressure difference between the propellers 423p according to the rotation direction and rotation speed of each propeller 423p.

[0046] The housing 41 of the drone 40 is formed in a box shape and houses various components of the drone 40. A plurality of legs 411 are provided on the underside of the housing 41 to support the drone 40 in a landing state.

[0047] 2 , the drone 40 has a drone-side control unit 43 inside the housing 41 that operates the flight structure unit 42 and controls the detection of gas in the air. The drone 40 also has a gas sensor 44 that detects gas in the air, an external sensor 45 that acquires external environmental information, an internal sensor 46 that acquires status information of the drone 40, a position sensor 47 that acquires the current position of the drone 40, a power supply unit 48, and a charging unit 49.

[0048] The drone-side control unit 43 is a computer having one or more processors 431, a memory 432, an input / output interface 433, and a communication interface 434. The one or more processors 431 are one or a combination of a central processing unit (CPU), a graphics processing unit (GPU), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a circuit made up of multiple discrete semiconductors, etc. The memory 432 includes a main storage device made up of a semiconductor memory, etc., and an auxiliary storage device made up of a disk, semiconductor memory (flash memory), etc.

[0049] The drone-side control unit 43 controls the operation of the drone 40 by having the processor 431 execute a program stored in the memory 432. For example, the drone-side control unit 43 communicates with the ground-side control unit 23, and upon receiving information of a lift-up trigger from the ground-side control unit 23, starts lift-up of the drone 40 from the ground robot 20 (transition from the first form to the second form). The drone-side control unit 43 also has an autonomous movement control function that automatically moves the drone 40 in the air. Furthermore, while the drone 40 is moving, the drone-side control unit 43 continuously detects gas using the gas sensor 44 and recognizes the current position (including altitude) of the drone 40, thereby linking the gas detection information with the current position.

[0050] The gas sensor 44 is configured similarly to the gas sensor 24 of the ground robot 20, and detects the state of gaseous chemical substances contained in the atmosphere (or predetermined gas components) in the air. For example, the gas sensor 44 may be a composite gas detector in which multiple sensor elements are arranged to distinguish and detect multiple types of chemical substances. The gas sensor 44 may be installed on the upper surface of the flight structure 42 or the lower surface of the housing 41, for example.

[0051] The gas detection system 1 is not limited to providing the gas sensors 24, 44 on the ground robot 20 and the drone 40, respectively. The gas detection system 1 only needs to provide the gas sensor 44 on at least the drone 40. This is because the gas sensor 44 on the drone 40 can be used when detecting gas on the ground using the assembly robot 10 in the first form. In short, in the first form, gas detection can be performed using either the gas sensor 24 on the ground robot 20 or the gas sensor 44 on the drone 40.

[0052] The external sensor 45 is connected to the drone-side control unit 43, detects external environmental information (information about objects) while the drone 40 is flying, and transmits the information to the drone-side control unit 43. This external sensor 45 can be configured by combining one or more of the sensors listed as the external sensor 25 of the ground robot 20. The external sensor 45 may also include a sensor (anemometer) for detecting the state of the wind (wind direction, wind speed) that the drone 40 experiences in the air.

[0053] The internal sensor 46 is connected to the drone control unit 43, detects information such as the current orientation and tilt of the drone 40 while the drone 40 is flying, and transmits this information to the drone control unit 43. The drone control unit 43 can appropriately adjust the attitude of the drone 40 while flying based on the information received from the internal sensor 46. An acceleration sensor, a gyro sensor, or the like can be used as this internal sensor 46.

[0054] The position sensor 47 is configured similarly to the position sensor 27, detects the current position of the drone 40, and transmits the information to the drone-side control unit 43. The position sensor 47 may include a barometric pressure sensor or the like to detect the altitude of the drone 40.

[0055] A secondary battery can be applied to the power supply unit 48, as in the ground robot 20. In the first mode in which the drone 40 is mounted on the ground robot 20 as described above, the charging unit 49 charges the power supply unit 48 from the power supply unit 29. Note that the charging unit 49 may be configured to be connected to an external power source separate from the power supply unit 29 of the ground robot 20 and charge the power supply unit 48.

[0056] Fig. 3 is a flowchart showing an example of a gas detection method according to an embodiment. The gas detection system 1 performs the gas detection method shown in Fig. 3 using the assembly robot 10 having the above-described ground robot 20 and drone 40. In the gas detection method, under the control of the ground-side controller 23 and the drone-side controller 43, a search area SA setting step (step S101), a rough search step (step S102), a fine search step (step S103), and an aerial search step (step S104) are performed in this order.

[0057] In the search area SA setting step (step S101), a search area SA for gas to be searched for by the assembly robot 10 is set by the user via a user interface (not shown) of the gas detection system 1. Note that the gas detection system 1 may operate the assembly robot 10 while the search area SA is unknown, and generate map information of the search area SA as the assembly robot 10 moves.

[0058] The rough search process (step S102: first search process) and the fine search process (step S103: second search step) are ground search processes in which gas is detected in a first configuration in which the drone 40 is mounted on the ground robot 20 to detect gas on the ground. In the rough search process, gas is detected by roughly moving the assembly robot 10 (ground robot 20) within a search area SA (first area) set by the user. In the fine search process, a detailed search area DA (second area) narrower than the search area SA is set based on the gas concentration detected in the rough search process, and the assembly robot 10 is moved precisely to detect gas. Finally, the aerial search process is a process in which gas is detected in a second configuration in which the drone 40 is lifted from the ground robot 20 to detect gas in the air. In this way, the gas detection system 1 detects gas in an arbitrary search area SA in both the first and second configurations, thereby enabling efficient and accurate search (estimation) of the three-dimensional coordinates of the gas leak location GL.

[0059] FIG. 4 is a block diagram showing functional units formed in the ground-side control unit 23 and the drone-side control unit 43 in the gas detection method. The ground-side control unit 23 has the various functional blocks shown in FIG. 4 by having the processor 231 execute a program stored in the memory 232. Specifically, the ground-side control unit 23 has a ground movement control unit 31, a gas sensor information acquisition unit 32, a gas concentration distribution creation unit 33, an ascent trigger generation unit 34, etc. formed therein. Meanwhile, the drone-side control unit 43 has the various functional blocks shown in FIG. 4 by having the processor 431 execute a program stored in the memory 432. Specifically, the drone-side control unit 43 has an air movement control unit 51, a gas sensor information acquisition unit 52, a gas concentration distribution creation unit 53, a gas leak estimation unit 54, etc. formed therein.

[0060] The ground movement control unit 31 is a functional unit that autonomously controls the movement of the ground robot 20 on the ground. For example, the ground movement control unit 31 pre-sets a target position or target direction within the search area SA and moves the ground robot 20 forward toward the set target position or target direction. Then, when the ground movement control unit 31 reaches the target position or moves a certain distance, it sets a new target position or target direction, changes the attitude of the ground robot 20 toward that new position, and moves forward again. Alternatively, the ground movement control unit 31 may calculate a target movement path based on stored map information of the search area SA and move the ground robot 20 along the target movement path.

[0061] During movement, the ground movement control unit 31 adjusts the movement control of the ground robot 20 in real time using external environmental information detected by the external sensor 25, status information of the ground robot 20 detected by the internal sensor 26, position information detected by the position sensor 27, etc. For example, if the external sensor 25 detects an object (avoidance target) ahead in the direction of movement of the ground robot 20, the ground movement control unit 31 may perform an avoidance operation to avoid (detour) the detected object and continue the movement of the ground robot 20. Furthermore, if the external sensor 25 detects unevenness or a rough road (avoidance target) such as a groove, hole, or protrusion, the ground movement control unit 31 may perform an avoidance operation to avoid the object and continue the movement of the ground robot 20.

[0062] As described above, the gas detection method performs a rough search process and a fine search process on the ground (see also FIG. 3 ). To this end, the ground movement control unit 31 has a rough search control unit 311 that controls the movement of the ground robot 20 in the rough search process, and a fine search control unit 312 that controls the movement of the ground robot 20 in the fine search process.

[0063] FIG. 5A is a plan view illustrating the movement of the assembly robot 10 during the rough search process. FIG. 5B is a plan view illustrating the movement range of the assembly robot 10 during the fine search process. As shown in FIG. 5A, the rough search control unit 311 moves the assembly robot 10 (ground robot 20) roughly (sparsely) within the search area SA and detects the gas concentration using the gas sensor 24 during this movement. In other words, "rough search" refers to moving the assembly robot 10 and detecting gas so that it passes through multiple spaced apart areas within the search area SA, omitting passage (gas detection) through the spaced apart areas. This allows the ground-side control unit 23 to quickly determine the general gas concentration distribution even in a large search area SA.

[0064] For example, the movement pattern of the assembly robot 10 in the rough search process may involve first circling the outer periphery of the search area SA and then moving within the search area SA. The rough search control unit 311 can map the outer periphery of the search area SA and recognize the range of the search area SA by continuously acquiring position information from the position sensor 27 during movement. If map information of the search area SA is prepared in advance, the rough search control unit 311 may use this map information to calculate the target position and target direction. Furthermore, in the rough search process, when the assembly robot 10 is repositioned from the outer periphery of the search area SA to the inside of the search area SA, the assembly robot 10 is moved with a certain interval (e.g., approximately 2 m to 5 m) between them. Alternatively, the movement pattern of the assembly robot 10 in the rough search process may involve setting multiple, approximately linear moving columns spaced apart within the search area SA, and moving each moving column forward or backward in sequence, or moving randomly within the search area SA.

[0065] Then, while the assembly robot 10 is moving, the gas sensor information acquisition unit 32 detects the gas concentration using the gas sensor 24 , acquires gas detection information from the gas sensor 24 , and stores the information in the memory 232 .

[0066] The gas concentration distribution creation unit 33 creates a gas concentration distribution map as shown in FIG. 5A based on the gas concentration information acquired by the gas sensor information acquisition unit 32. The gas concentration distribution map is generated as information linking the positions acquired by the position sensor 27 during the movement of the assembly robot 10 with the gas concentrations acquired by the gas sensors 24. This allows the ground-side control unit 23 to recognize the gas concentration distribution on the ground. Note that, in this disclosure, "recognizing the concentration distribution" refers to performing a calculation to associate concentrations with position information. Therefore, the gas concentration distribution map does not need to be created by the ground-side control unit 23. For example, even when an external information processing device (including the drone 40) transmits the results of a calculation linking individual gas concentrations with individual position information to create a gas concentration distribution map, it can also be said that the ground-side control unit 23 recognizes the concentration distribution.

[0067] Locations with high gas concentrations in the gas concentration distribution map can be considered to be close to the gas leak location GL. Therefore, the ground-side control unit 23 sets a detailed search area DA for the next fine search process so that it includes the location where the gas concentration detected in the rough search process is highest. For example, as shown in FIG. 5B , the detailed search area DA can be set as a virtual circle centered on the location where the gas concentration is highest and with a radius equal to the distance between the sections passed by the assembly robot 10 in the rough search process. The detailed search area DA set in this manner is significantly smaller than the search area SA in the rough search process, so that a decrease in work efficiency can be suppressed even if the assembly robot 10 moves in detail within the detailed search area DA in the fine search process.

[0068] The fine search control unit 312 moves the assembly robot 10 precisely (closely) within the detailed search area DA, and detects the concentration of chemical substances using the gas sensor 24 during this movement. In other words, "fine search" means moving the assembly robot 10 and detecting gas within the detailed search area DA, which is smaller than the search area SA, and extracting the location with the highest gas concentration. As a result, the ground-side control unit 23 can recognize ground positions with high gas concentrations throughout the entire search area SA.

[0069] Fig. 6(A) is a block diagram illustrating the processing and judgment of the fine search control unit 312 in the fine search process. Fig. 6(B) is an explanatory diagram showing an example of the operation of the assembly robot 10 in the fine search process. As shown in Fig. 6(A), the fine search control unit 312 may set the movement direction, forward and backward operations of the ground robot 20 based on the concentration of gas detected by the gas sensor 24.

[0070] For example, the fine search control unit 312 may switch the movement and movement direction of the assembly robot 10 using a gas concentration gradient method. As an example, the fine search control unit 312 determines whether the gas concentration detected at the current position has increased or decreased compared to the gas concentration detected at the previous position. If the gas concentration at the current position has increased compared to the gas concentration at the previous position, the fine search control unit 312 advances a set distance and detects the gas concentration at the advanced position (new current position). This "set distance" is a value shorter than the interval between portions of the rough search process, and may be set to an appropriate value within a range of, for example, approximately 300 mm to 1000 mm.

[0071] On the other hand, if the gas concentration at the current position is lower than the gas concentration at the previous position, the assembly robot 10 retreats once, then changes the angle of the assembly robot 10 and moves forward a set distance, and the gas concentration is detected at the advanced position (new current position). This makes it possible to prevent the assembly robot 10 from moving in the direction of a lower gas concentration and move the assembly robot 10 in the direction of a higher gas concentration.

[0072] Using the above rules, the assembly robot 10 performs operations such as those shown in FIG. 6B to search for the position with the highest gas concentration in the detailed search area DA. For example, assume that the assembly robot 10 advances to the left in FIG. 6B during its first movement after moving into the detailed search area DA. The assembly robot 10 then compares the gas concentration at its current position with the gas concentration at its start position (previous position) to detect a decrease in gas concentration. As a result, the assembly robot 10 retreats to the start position and then advances downward in FIG. 6B during its second movement. If a decrease in gas concentration is detected during this second movement, the assembly robot 10 also retreats to the start position and then performs a third movement. During the third movement, the assembly robot 10 advances upward in FIG. 6B. The assembly robot 10 then detects that the gas concentration at its current position, to which it has advanced upward, is higher than the gas concentration at its start position.

[0073] Based on the increase in gas concentration, the assembly robot 10 advances further upward in FIG. 6(B) during its fourth movement. If the assembly robot 10 detects a decrease in gas concentration at its current position after advancing, it retreats to the position to which it moved the third time and then moves a fifth time. During its fifth movement, it advances to the right in FIG. 6(B), a direction it has not moved in so far. This is because there is a higher probability of an increase in gas concentration in a direction it has not moved in so far. The assembly robot 10 then detects that the gas concentration at its current position after advancing rightward has increased compared to the gas concentration at the position immediately before its third movement.

[0074] Based on the increase in gas concentration, the assembly robot 10 further advances to the right in FIG. 6B during its sixth movement. If the assembly robot 10 detects a decrease in gas concentration at its current position after advancing, it retreats to the position where it moved to the fifth time and then performs its seventh movement. During the seventh movement, it advances, for example, downward in FIG. 6B. If the assembly robot 10 also detects a decrease in gas concentration during the seventh movement, it retreats to the position where it moved to the fifth time and then performs its eighth movement. During the eighth movement, it advances, for example, upward in FIG. 6B. If the assembly robot 10 also detects a decrease in gas concentration during the eighth movement, it retreats to the position where it moved to the fifth time and recognizes that position as the position with the highest gas concentration. Note that the gas concentration gradient method is an example of a fine search process and is not limited to this. For example, the ground-side control unit 23 may move the assembly robot 10 evenly throughout the fine search area DA to detect the gas concentration.

[0075] Then, in the fine search process, the ground-side control unit 23 detects the gas concentration in the detailed search area DA and sets the location with the highest gas concentration as the ground position from which the drone 40 will take off. After setting, the assembly robot 10 moves to the ground position and transitions from the first form to the second form, thereby executing the flight search process (step S103 in FIG. 3 ).

[0076] At this time, the floating trigger generating unit 34 of the ground-side control unit 23 communicates with the drone 40 and transmits floating trigger information from the ground robot 20 to start floating of the drone 40. When the drone 40 receives this floating trigger information, it starts driving each propeller mechanism 423 and floats vertically upward from the ground robot 20. In addition, the ground-side control unit 23 releases the drone 40 from being tethered by the engagement structure 221 in response to the generation of the floating trigger.

[0077] Returning to FIG. 4 , the drone-side control unit 43 autonomously controls the flight of the drone 40 using the aerial movement control unit 51. For example, the aerial movement control unit 51 causes the drone 40 to ascend vertically upward from a ground position set by the ground robot 20. During the ascent, the aerial movement control unit 51 adjusts the movement control of the ground robot 20 in real time using external environmental information detected by the external sensor 45, status information of the drone 40 detected by the internal sensor 46, position information detected by the position sensor 47, and the like. For example, if the external sensor 45 detects an object vertically above the drone 40 (forward in the direction of movement), the aerial movement control unit 51 may perform an avoidance operation to avoid (circumvent) the detected object and continue the movement of the drone 40.

[0078] In the aerial search step of the gas detection method, gas is detected while the drone 40 is ascending (floating) (hereinafter also referred to as the ascent search step). For this reason, the aerial movement control unit 51 includes an ascent control unit 511 therein that controls the operation of the drone 40 during ascent.

[0079] The ascent control unit 511 synchronizes the operation of each propeller mechanism 423 to ascend the drone 40 at a constant speed, for example. Even when there is wind in the flight environment, the ascent control unit 511 independently controls the rotation speed of each propeller mechanism 423 to keep the drone 40 from deviating too far from its set ground position, thereby continuing the ascent. This makes it possible for the drone 40 to ascend while generally maintaining its position vertically above its ground position.

[0080] Then, the gas sensor information acquisition unit 52 of the drone side control unit 43 detects the gas concentration using the gas sensor 44 while the drone 40 is ascending during the ascent search process, acquires the gas detection information from the gas sensor 44 and stores it in the memory 432.

[0081] FIG. 7 is an explanatory diagram showing the operation of the ascending search process and gas detection of the gas detection method. During the ascending search process, the drone 40 ascends vertically upward as shown in the left diagram of FIG. 7 and detects the gas concentration during this ascent. The drone 40's position sensor 47 continuously detects the drone 40's altitude as it ascends and transmits this position information to the drone-side control unit 43. The gas concentration distribution creation unit 53 creates a gas concentration distribution map as shown in the right diagram of FIG. 7 by linking the gas concentration acquired by the gas sensor information acquisition unit 52 with the drone 40's altitude (position information). This allows the drone-side control unit 43 to recognize the gas concentration distribution in the air. Note that the drone-side control unit 43 does not need to create the gas concentration distribution map internally. For example, even if an external information processing device (including the ground robot 20) transmits calculation results linking individual gas concentrations with individual position information to create a gas concentration distribution map, the drone-side control unit 43 can still be said to recognize the concentration distribution.

[0082] The plot of the gas concentration distribution map in the upward search process exhibits a mountain-like shape in which the gas concentration is highest near the gas leak location GL. The gas leak estimation unit 54 of the drone control unit 43 can regard the peak of the mountain-like shape of the gas concentration distribution map obtained in the upward search process of the drone 40 as being closest to the gas leak location GL. For example, when the gas leak estimation unit 54 estimates the gas leak location GL, it creates report information of the gas leak location GL to be shown to the user and outputs the report information to a user interface (monitor, printer) of the gas detection system 1.

[0083] The ascent control unit 511 may, for example, refer to the gas detection information when controlling the ascent of the drone 40 and continue ascent until the gas concentration exceeds the peak of the mountain shape. This allows the gas leak estimation unit 54 to more reliably identify the location GL of the gas leak.

[0084] Note that the gas leak location GL may shift horizontally from the position where the drone 40 is airborne due to wind influences. For this reason, the aerial movement control unit 51 may include a horizontal search control unit 512 in addition to the ascent control unit 511, and the horizontal search control unit 512 may move the drone 40 horizontally to detect the gas concentration. For example, the drone-side control unit 43 may move the drone 40 horizontally at a position where the gas concentration is highest during the ascent search process to detect the gas in its surroundings (hereinafter also referred to as the horizontal search process). This allows the drone 40 to detect a position in the air where the gas concentration is highest and estimate that position as the gas leak location GL. Alternatively, the gas leak estimation unit 54 may estimate the position of the gas leak location GL using information on the wind direction and wind speed in the air detected by the external sensor 45.

[0085] The gas detection system 1 may include an information processing device 90 that is external to the assembly robot 10 and communicates with the assembly robot 10. The information processing device 90 may be a computer that includes a processor, memory, an input / output interface, a communication interface, etc. (not shown). The information processing device 90 may be a mobile phone terminal including a smartphone, a tablet, a laptop computer, a wearable computer, etc. The information processing device 90 may, for example, function as a user interface that outputs the above-mentioned report information. The user interface may be installed on the housing 22 of the ground robot 20, etc.

[0086] Furthermore, the information processing device 90 may have some of the functions of the ground-side control unit 23 of the ground robot 20 and the drone-side control unit 43 of the drone 40. For example, the information processing device 90 may have gas sensor information acquisition units 32, 52, gas concentration distribution creation units 33, 53, and a gas leak estimation unit 54, and may receive information on gas detected by the gas sensors 24, 44, create a gas concentration distribution map, and estimate the location GL of the gas leak.

[0087] In the above embodiment, the ground robot 20 and the drone 40 are configured to operate under autonomous control. However, the gas detection system 1 is not limited to this, and for example, the information processing device 90 may be provided with a ground movement control unit 31 and an aerial movement control unit 51. This allows the gas detection system 1 to be configured such that operation commands are sent from the information processing device 90 to the ground robot 20 and the drone 40, thereby remotely controlling each device.

[0088] Furthermore, the gas detection system 1 of the present disclosure is not limited to the above embodiment and may take various modifications. For example, in the gas detection in the first mode, the assembly robot 10 may perform only one of the rough search process and the fine search process, rather than both. As an example, if the search area SA is small, time loss can be reduced by performing the fine search process from the beginning.

[0089] The external sensors 25, 45 do not necessarily have to be provided on both the ground robot 20 and the drone 40, but may be provided only on the drone 40. In the ground exploration process by the ground robot 20 (assembly robot 10), information from the external sensor 45 of the drone 40 can be used to perform object avoidance operations, etc.

[0090] In the gas detection system 1 described above, a configuration in which one drone 40 is mounted on one ground robot 20 has been described. This allows the ground robot 20 to easily transport the drone 40 and smoothly detect gas while reducing energy consumption on the ground. However, the assembly robot 10 may also mount multiple drones 40 on one ground robot 20. This allows, for example, when gas concentrations are high at multiple locations on the ground, to take measures such as lifting the drones 40 at each location.

[0091] In addition, the gas detection system 1 may not only use the assembly robot 10 to search for the location GL of the gas leak, but may also use information on the detected gas to analyze the type and amount of gas in the atmosphere.

[0092] Next, a gas detection system 1A according to a second embodiment of the present disclosure will be described with reference to FIGS. 8 to 10. FIG. 8 is a side view showing the overall configuration of the gas detection system 1A according to the second embodiment. FIG. 9 is a block diagram showing functional units formed in the ground-side control unit 23 and the drone-side control unit 43 of the gas detection system 1A. FIG. 10 is a flowchart showing an example of a gas detection method according to the second embodiment.

[0093] 8, the gases (chemical substances) detected by the gas detection system 1A include gases with a high specific gravity relative to the atmosphere and gases with a low specific gravity. Gases with a high specific gravity flow in a direction lower than the gas leak location GL, while gases with a low specific gravity flow in a direction higher than the gas leak location GL. When multiple types of gases are leaking or when the type of leaking gas is unknown, the specific gravity of the leaking gas increases the likelihood that the estimated gas leak location GL will be inaccurate.

[0094] For this reason, the gas detection system 1A acquires the specific gravity and gas concentration of the gas detected by the gas sensors 24, 44, and uses this information to set the operation details of the assembly robot 10 (ground robot 20, drone 40). Specifically, as shown in Fig. 9, the ground-side control unit 23 of the ground robot 20 includes an internal specific gravity / concentration determination processing unit 35 that identifies the specific gravity of the gas based on the detection information acquired by the gas sensor information acquisition unit 32 and determines the gas concentration. Furthermore, the drone-side control unit 43 of the drone 40 also includes an internal specific gravity / concentration determination processing unit 55 that has the same function.

[0095] The specific gravity concentration determination processing unit 35 of the ground robot 20 stores, for example, table information describing the specific gravity of each of a plurality of types of gas in advance, and when it recognizes the type of gas in the acquired detection information, it extracts the specific gravity of the gas corresponding to that type of gas. As a result, the specific gravity concentration determination processing unit 35 can recognize that a gas with a high specific gravity is leaking when the specific gravity of the detected gas is equal to or higher than that of the atmosphere (when the specific gravity is 1.0 or higher).

[0096] The specific gravity concentration determination processing unit 35 then compares the detected concentration of the high specific gravity gas with a pre-stored ground threshold to determine whether the gas concentration is equal to or greater than the ground threshold. The ground threshold is equal to or greater than the value at which the gas naturally mixes into the atmosphere, and may be set to an appropriate value depending on the type of gas. If the concentration of the high specific gravity gas is equal to or greater than the ground threshold, the ground-side control unit 23 can recognize that the high specific gravity gas is flowing on the ground.

[0097] Meanwhile, the specific gravity concentration determination processing unit 55 of the drone 40 also stores in advance table information describing the specific gravity of each of multiple types of gas, and when it recognizes the type of gas in the acquired detection information, it extracts the specific gravity of the gas corresponding to that type of gas. As a result, the specific gravity concentration determination processing unit 55 can recognize that a gas with a low specific gravity is leaking when the specific gravity of the detected gas is lower than that of the atmosphere (when the specific gravity is less than 1.0).

[0098] The specific gravity concentration determination processing unit 55 then compares the detected concentration of the low-specific gravity gas with a pre-stored air threshold to determine whether the gas concentration is equal to or greater than the air threshold. The air threshold is also equal to or greater than the value at which the gas naturally mixes into the atmosphere and may be set to an appropriate value depending on the type of gas. In other words, the air threshold may be different from the ground threshold. If the concentration of the low-specific gravity gas is equal to or greater than the air threshold, the drone-side control unit 43 can recognize that low-specific gravity gas is flowing in the air.

[0099] The gas detection system 1A is basically configured as described above, and the following describes a gas detection method according to the second embodiment. The gas detection method according to the second embodiment sequentially executes steps S201 to S214 shown in Figure 10 under the control of the ground-side controller 23 and the drone-side controller 43.

[0100] Steps S201 to S203 of the gas detection method according to the second embodiment basically follow the same processing flow as steps S101 to S103 of the gas detection method according to the first embodiment, and therefore, a description of steps S201 to S203 will be omitted.

[0101] After the fine search process, the specific gravity concentration determination processing unit 35 of the assembly robot 10 determines whether the specific gravity of the gas detected in the fine search is equal to or greater than atmospheric gravity, and whether the concentration of the gas is equal to or greater than the ground threshold (step S204). That is, since gases equal to or greater than atmospheric gravity flow to the ground, by monitoring gases with a specific gravity equal to or greater than atmospheric gravity in detecting gases on the ground, the state of a gas leak can be accurately identified. If the specific gravity of the gas is equal to or greater than atmospheric gravity and the gas concentration is equal to or greater than the ground threshold (step S204: YES), the ground-side control unit 23 determines to transition to the second mode and proceeds to step S205.

[0102] In step S205, the assembly robot 10 moves to the ground position where the gas concentration is highest, and causes the drone 40 to rise from the ground robot 20 to perform an ascent search process (aerial search process). This ascent search process is basically the same as step S104 in the first embodiment, and a detailed description thereof will be omitted. Note that, in addition to this ascent search process, the drone 40 may also perform a horizontal search process in which the drone 40 moves horizontally at an appropriate altitude.

[0103] In step S205, the drone 40 ascends while basically detecting gases with specific gravity equal to or greater than that of atmosphere, but it may also detect gases with specific gravity less than that of atmosphere. In other words, when searching for a gas leak without knowing the type of gas, there is a possibility that not only gases with specific gravity equal to or greater than that of atmosphere will leak, but also gases with specific gravity less than that of atmosphere will leak. Therefore, the specific gravity concentration determination processing unit 55 of the drone 40 determines whether the specific gravity of the gas detected in the aerial search process is less than that of atmosphere, and also determines whether the concentration of the gas is equal to or greater than the air threshold (step S206).

[0104] Because gases with a specific gravity less than that of atmospheric air rise or float in the air, the presence of such gases can be recognized by monitoring the gases in the air. If no gas with a specific gravity less than that of atmospheric air is detected, or if a gas with a specific gravity less than that of atmospheric air is detected but its concentration is less than the air threshold (step S206: NO), it can be recognized that no gas with a specific gravity less than that of atmospheric air is leaking. Therefore, in step S207, the drone-side control unit 43 ends gas detection by the drone 40 and lands the drone 40 on the ground robot 20.

[0105] Then, the gas leak estimation unit 54 of the drone side control unit 43 estimates the location GL of the gas leak based on the gas concentration distribution map of gases with specific gravity higher than that of atmosphere detected in the aerial search process, and notifies the user interface of the report information (step S208).

[0106] On the other hand, in step S204, if the specific gravity concentration determination processing unit 35 does not detect a gas with a specific gravity equal to or greater than that of the atmosphere, or if it detects a gas with a specific gravity equal to or greater than that of the atmosphere but the concentration of the gas is less than the ground threshold (step S204: NO), it transitions to a mode for searching for gases with a specific gravity less than that of the atmosphere. In other words, since it can be assumed that no gas with a specific gravity equal to or greater than that of the atmosphere has leaked in the current gas search, the gas detection method is switched to a search for gases with a lower specific gravity.

[0107] Here, when searching for gases with a specific gravity less than that of atmospheric air, there is a high possibility that the results of gas detection on the ground will not be usable. Because gases with a specific gravity less than that of atmospheric air move easily through the air, even if a location with a high gas concentration is identified on the ground, it is not necessarily the case that the gas leak location GL is located directly above that location. For this reason, in the mode for searching for gases with a specific gravity less than that of atmospheric air, multiple designated locations 1 through N are set where the drone 40 will fly, and a flight search process is performed by the drone 40 (second mode) at each designated location. The designated locations 1 through N may be set, for example, in a matrix with appropriate spacing based on map information of the search area SA. The spacing between the designated locations 1 through N may be approximately 2 to 5 meters.

[0108] Specifically, in step S209, the assembly robot 10 (ground robot 20) moves to one of a plurality of designated locations 1 to N. Then, at the designated location, the assembly robot 10 transitions to the second form, causes the drone 40 to levitate, and performs an ascent search process (step S210).

[0109] In this ascending search process, the specific gravity concentration determination processing unit 55 of the drone 40 determines whether the specific gravity of the gas is less than that of the atmosphere, as in step S206, and whether the concentration of the gas is equal to or greater than the air threshold (step S211). This allows the drone-side control unit 43 to determine whether a gas with a specific gravity less than that of the atmosphere is present vertically above the specified location.

[0110] If the specific gravity concentration determination processing unit 55 detects a gas with a specific gravity less than that of atmospheric air and the concentration of the gas is equal to or greater than the airborne threshold (step S211: YES), it recognizes that a gas with a specific gravity less than that of atmospheric air is present around the drone 40. In this case, the drone-side control unit 43 executes a horizontal search process in which the drone moves horizontally around the location to detect the gas (step S212). During this process, the gas concentration distribution creation unit 53 creates a gas concentration distribution map associated with the horizontal search process, thereby enabling identification of the location with the highest gas concentration. In other words, performing the horizontal search process enables more accurate detection of locations with high concentrations of gas with a specific gravity less than that of atmospheric air. The range of this horizontal search process may be set based on the spacing between adjacent designated locations 1 through N, for example, a range of 2 m to 5 m.

[0111] Furthermore, after performing the upward search process based on a gas with a specific gravity equal to or greater than that of atmosphere, the drone-side control unit 43 also performs the horizontal search process (step S212) when it detects a gas with a specific gravity less than that of atmosphere and the concentration of the gas is equal to or greater than the air threshold (step S206: YES). This enables the gas detection system 1 to estimate the location GL of the gas leak for both a gas with a specific gravity equal to or greater than that of atmosphere and a gas with a specific gravity less than that of atmosphere.

[0112] After step S212 is performed to estimate the location GL of the gas leak, the process proceeds to step S207, and the ground robot 20 lands the drone 40. Then, in step S208, the gas leak estimation unit 54 estimates the location GL of the gas leak based on the gas concentration distribution map, and notifies the user interface of the report information.

[0113] On the other hand, in step S211, if the specific gravity concentration determination processing unit 55 does not detect a gas with a specific gravity less than that of the atmosphere, or if the specific gravity concentration determination processing unit 55 detects a gas with a specific gravity less than that of the atmosphere but the concentration of the gas is less than the air threshold (step S211: NO), the drone-side control unit 43 ends detection of the specified location. As a result, the drone-side control unit 43 lands the drone 40 on the ground robot 20 (step S213).

[0114] After step S213, the drone-side control unit 43 determines whether or not all of the designated locations 1 to N have been searched (step S214). If this determination determines that there are designated locations that have not been searched (step S214: NO), the process returns to step S209, and the same processing flow is performed thereafter.

[0115] If there are no specified locations that have not been searched (step S214: YES), it means that no gas leak has occurred for a gas with a specific gravity less than that of the atmosphere. Therefore, the process proceeds to step S208, and the gas leak estimation unit 54 notifies the user interface of report information indicating that the gas leak location GL could not be found. This allows the user to smoothly recognize that there has been no gas leak in the search area SA.

[0116] The above-disclosed embodiment has, for example, the following aspects and effects.

[0117] [Supplementary Note 1] A gas detection system comprising: a ground vehicle capable of moving on the ground; one or more flying bodies mounted on the ground vehicle and capable of floating in the air; and a sensor mounted on at least the one or more flying bodies for detecting chemical substances in gas, wherein the gas detection system performs detection with the sensor in a first configuration in which the one or more flying bodies are mounted on the ground vehicle, and then transitions to a second configuration in which the one or more flying bodies are caused to float from the ground vehicle and perform detection with the sensor.

[0118] [Effects of Supplementary Note 1] The above-described gas detection system can efficiently detect the state of chemical substances while reducing power consumption. That is, by detecting chemical substances in the first configuration in which the flying object is mounted on a ground vehicle, it is possible to reduce the number of times the flying object takes off, thereby significantly reducing the power consumption associated with the flying object taking off. Furthermore, since fewer opportunities for the flying object to take off can be reduced, disturbance of chemical substances in the air can be reduced, and the gas detection system can detect chemical substances in the second configuration in a short period of time. As a result, the gas detection system can quickly recognize the state of chemical substances in three-dimensional space.

[0119] [Appendix 2] The gas detection system described in Appendix 1, wherein the ground vehicle sets a ground position at which the one or more flying bodies will take off based on the concentration of the chemical substance detected by the sensor in the first form, and moves to that ground position, and the one or more flying bodies transition to the second form at the ground position.

[0120] [Effect of Supplementary Note 2] The gas detection system can more efficiently search for locations with high concentrations of chemical substances by setting the ground position at which to transition to the second mode based on the concentration of chemical substances detected in the first mode.

[0121] [Supplementary Note 3] The gas detection system described in Supplementary Note 2, wherein in the first form, the ground moving body executes a first search step of moving within a first area and performing detection with the sensor, and a second search step of setting a second area that is narrower than the first area based on the detection result of the first search step, moving within the second area and performing detection with the sensor to set the ground position.

[0122] [Effects of Supplementary Note 3] By performing the first search step and the second search step, the gas detection system can efficiently detect chemical substances even in a wide search area, for example.

[0123] [Supplementary Note 4] The gas detection system according to Supplementary Note 3, wherein the second area is a position in the first area where the concentration of the chemical substance is highest and its surroundings.

[0124] [Effect of Supplementary Note 4] By setting the location where the concentration of the chemical substance detected in the first area is the highest as the second area, the gas detection system can narrow the second area sufficiently and more accurately search for locations where the concentration of the chemical substance is high.

[0125] [Supplementary Note 5] The gas detection system according to Supplementary Note 4, wherein the ground location is a location in the second area where the concentration of the chemical substance is highest.

[0126] [Effect of Supplementary Note 5] The gas detection system can efficiently search for areas with high concentrations of chemical substances when the aircraft is airborne by setting the ground position to the position where the concentration of the chemical substance detected in the second area is highest.

[0127] [Supplementary Note 6] The gas detection system according to any one of claims 1 to 5, wherein the sensor is provided in each of the one or more flying vehicles and the ground vehicle.

[0128] [Effect of Supplementary Note 6] By providing a sensor in each of the flying vehicle and the ground moving vehicle, the gas detection system can appropriately detect gas on the ground and in the air using each sensor.

[0129] [Supplementary Note 7] The gas detection system according to any one of Supplementary Notes 1 to 6, wherein the ground vehicle detects the concentration of the chemical substance using the sensor while moving in the first configuration, and recognizes a concentration distribution of the chemical substance on the ground.

[0130] [Effect of Supplementary Note 7] The gas detection system detects chemical substances while moving on the ground, which makes it possible to significantly reduce the time required for detection compared to when detection is performed by repeatedly moving and stopping.

[0131] [Supplementary Note 8] The gas detection system described in any one of Supplementary Notes 1 to 7, wherein the one or more flying vehicles detect the concentration of the chemical substance using the sensor while moving in the second form and recognize the concentration distribution of the chemical substance in the air.

[0132] [Effect of Supplementary Note 8] The gas detection system detects chemical substances while moving through the air, making it possible to significantly reduce the time required for detection in the air.

[0133] [Supplementary Note 9] The gas detection system described in any one of Supplementary Notes 1 to 8, further comprising a processing unit that recognizes the specific gravity of the chemical substance relative to the atmosphere and the concentration of the chemical substance based on the detection information detected by the sensor, and sets control details for the ground vehicle and / or the one or more flying vehicles.

[0134] [Effect of Supplementary Note 9] The gas detection system can perform appropriate detection according to the flow (positional change) of chemical substances in the air by setting the control content based on the specific gravity of the chemical substances.

[0135] [Supplementary Note 10] The gas detection system described in Supplementary Note 9, wherein the processing unit, when detecting the chemical substance having a specific gravity equal to or greater than that of atmosphere in the first mode and the concentration of the chemical substance is equal to or greater than a threshold value for ground use, transitions to the second mode and performs detection by the sensor, and when not detecting the chemical substance having a specific gravity equal to or greater than that of atmosphere in the first mode, or detecting the chemical substance having a specific gravity equal to or greater than that of atmosphere and the concentration of the chemical substance is less than the threshold value for ground use, transitions to the second mode and performs detection by the sensor after moving the ground vehicle to a set position.

[0136] [Effect of Supplementary Note 10] This allows the gas detection system to appropriately detect chemical substances with specific gravity equal to or greater than that of the atmosphere both on the ground and in the air.

[0137] [Supplementary Note 11] The gas detection system described in any one of Supplementary Notes 1 to 10, wherein at least one of the ground moving body and the one or more flying bodies is equipped with an external sensor that acquires information on terrain and / or objects present in the direction of movement, and when moving in the first form and / or moving in the second form, if an object to be avoided is present in the direction of movement based on detection by the external sensor, the gas detection system avoids the object to be avoided and continues moving.

[0138] [Effect of Supplementary Note 11] As a result, the gas detection system can stably detect chemical substances by preventing the ground vehicle and the flying vehicle from coming into contact with objects.

[0139] [Supplementary Note 12] The gas detection system according to any one of Supplementary Notes 1 to 11, wherein the ground vehicle has a power supply unit that supplies power to the one or more flying vehicles in at least one of the first configuration and the second configuration.

[0140] [Effect of Supplementary Note 12] This allows the flying object to prevent detection from being interrupted midway due to a power shortage during flight.

[0141] [Supplementary Note 13] The gas detection system according to any one of Supplementary Notes 1 to 12, wherein one of the one or more flying vehicles is mounted on the ground vehicle.

[0142] [Effect of Supplementary Note 13] As a result, the gas detection system can suppress the disturbance of gas in the air caused by the flying of many flying objects, and can narrow down the focus to search for the location of the gas leak.

[0143] [Supplementary Note 14] The gas detection system according to any one of Supplementary Notes 1 to 13, wherein the sensor distinguishes and detects a plurality of types of the chemical substances.

[0144] [Effect of Supplementary Note 14] The gas detection system can detect a variety of chemical substances by distinguishing between different types of chemical substances, thereby further increasing its versatility.

[0145] [Supplementary Note 15] The gas detection system described in any one of Supplementary Notes 1 to 14, wherein at least one of the ground moving body and the one or more air vehicles transmits the information detected by the sensor to the other of the ground moving body and the one or more air vehicles, or transmits the information to an information processing device different from the ground moving body and the one or more air vehicles.

[0146] [Effect of Supplementary Note 15] The gas detection system can make it easier to understand the state of chemical substances by aggregating the detection information from sensors of a ground vehicle and one or more air vehicles.

[0147] [Supplementary Note 16] A gas detection method for detecting chemical substances in gas, comprising: a ground search step of moving in a first configuration in which a ground mobile body capable of moving on the ground is equipped with one or more flying bodies capable of floating in the air, and detecting the chemical substances using sensors provided on at least the one or more flying bodies; and an aerial search step of, after the ground search step, transitioning from the ground mobile body to a second configuration in which the one or more flying bodies are floated, and detecting the chemical substances using the sensors.

[0148] [Effect of Supplementary Note 16] The above gas detection method can also reduce power consumption and efficiently detect the state of chemical substances.

[0149] The gas detection systems 1, 1A and gas detection methods according to the presently disclosed embodiments are illustrative in all respects and not restrictive. The embodiments can be modified and improved in various ways without departing from the spirit and scope of the appended claims. The features described in the above embodiments can be configured in other ways and can be combined together without conflict.

[0150] This application claims priority from basic application No. 2023-105370, filed with the Japan Patent Office on June 27, 2023, the entire contents of which are incorporated herein by reference.

[0151] REFERENCE SIGNS LIST 1, 1A Gas detection system 10 Assembly robot 20 Ground robot (ground moving body) 23 Ground-side control unit 24, 44 Gas sensor 25, 45 External sensor 29 Power supply unit 40 Drone (aircraft body) 43 Drone-side control unit 90 Information processing device

Claims

1. A gas detection system comprising: a ground moving body capable of moving on the ground; one or more flying bodies mounted on said ground moving body and capable of floating in the air; and a sensor mounted on at least said one or more flying bodies for detecting chemical substances in a gas, wherein the gas detection system performs detection with the sensor in a first form in which said one or more flying bodies are mounted on said ground moving body, and then transitions to a second form in which said one or more flying bodies are caused to float from said ground moving body and perform detection with the sensor.

2. The gas detection system described in claim 1, wherein the ground vehicle sets a ground position at which the one or more flying bodies will take off based on the concentration of the chemical substance detected by the sensor in the first form and moves to that ground position, and the one or more flying bodies transition to the second form at the ground position.

3. The gas detection system of claim 2, wherein the ground vehicle, in the first form, executes a first search step of moving within a first area and performing detection with the sensor, and a second search step of setting a second area narrower than the first area based on the detection result of the first search step, moving within the second area, performing detection with the sensor, and setting the ground position.

4. The gas detection system according to claim 3, wherein the second area is a location in the first area where the concentration of the chemical substance is the highest and its surroundings.

5. The gas detection system of claim 4, wherein the ground location is a location in the second area where the concentration of the chemical is highest.

6. The gas detection system according to any one of claims 1 to 5, wherein the sensor is provided in each of the one or more flying vehicles and the ground vehicle.

7. A gas detection system as claimed in any one of claims 1 to 6, wherein the ground vehicle detects the concentration of the chemical substance using the sensor while moving in the first form, and recognizes the concentration distribution of the chemical substance on the ground.

8. A gas detection system as described in any one of claims 1 to 7, wherein the one or more flying objects detect the concentration of the chemical substance using the sensor while moving in the second form, and recognize the concentration distribution of the chemical substance in the air.

9. A gas detection system as described in any one of claims 1 to 8, further comprising a processing unit that recognizes the specific gravity of the chemical substance relative to the atmosphere and the concentration of the chemical substance based on detection information detected by the sensor, and sets control contents for the ground vehicle and / or the one or more flying vehicles.

10. The gas detection system described in claim 9, wherein the processing unit, when detecting the chemical substance having a specific gravity equal to or greater than that of air in the first form and the concentration of the chemical substance is equal to or greater than a ground threshold value, transitions to the second form to perform detection by the sensor, and when not detecting the chemical substance having a specific gravity equal to or greater than that of air in the first form or detecting the chemical substance having a specific gravity equal to or greater than that of air and the concentration of the chemical substance is less than the ground threshold value, transitions to the second form to perform detection by the sensor after moving the ground vehicle to a set position.

11. A gas detection system as described in any one of claims 1 to 10, wherein at least one of the ground moving body and the one or more flying bodies is equipped with an external sensor that acquires information on terrain and / or objects present in the direction of movement, and when moving in the first form and / or moving in the second form, if an object to be avoided is present in the direction of movement based on detection by the external sensor, the object to be avoided is avoided and the movement is continued.

12. The gas detection system according to any one of claims 1 to 11, wherein the ground vehicle has a power supply unit that supplies power to the one or more flying vehicles in at least one of the first configuration and the second configuration.

13. The gas detection system according to any one of claims 1 to 12, wherein one of the one or more flying objects is mounted on the ground vehicle.

14. The gas detection system according to any one of claims 1 to 13, wherein the sensor distinguishes and detects a plurality of types of the chemical substances.

15. A gas detection system as described in any one of claims 1 to 14, wherein at least one of the ground moving body and the one or more air vehicles transmits information detected by the sensor to the other of the ground moving body and the one or more air vehicles, or transmits the information to an information processing device different from the ground moving body and the one or more air vehicles.

16. A gas detection method for detecting chemical substances in a gas, comprising: a ground search process in which a ground mobile vehicle capable of moving on the ground moves in a first form equipped with one or more flying bodies capable of floating in the air, and detects the chemical substances using sensors provided on at least the one or more flying bodies; and an aerial search process in which, after the ground search process, the ground mobile vehicle transitions to a second form in which the one or more flying bodies have floated from the ground mobile vehicle, and the chemical substances are detected using the sensors.

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