An unknown environment radioactive source autonomous search method, device and system

Abstract

The application provides a kind of unknown environment radioactive source autonomous search method, device and system, compared with the method currently adopted, not only guarantee the safety of staff, reduce the possibility that radioactive source search personnel is injured by radiation;At the same time, the service life of robot in radiation environment is also considered, the absorbed dose of robot in the process of radioactive source search is reduced, so that the service life of robot can be extended, and the use cost of long-term search of radioactive source of robot is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of robot control, in particular to a method, device and system for autonomous search of radioactive sources in unknown environments. BACKGROUND

[0002] With the continuous development of nuclear industry and nuclear technology, radioactive sources and ray devices have been widely used in the fields of industry, agriculture, medical treatment and scientific research, and have made important contributions to promoting economic and social development. However, due to the particularity of radioactive substances, once out of control, it will seriously threaten the health and safety of the public. Therefore, after the occurrence of relevant accidents, the search and positioning of radioactive sources in unknown locations must be processed as soon as possible

[0003] The traditional search method for radioactive sources mainly relies on manual carrying of portable detection instruments for inspection and search, but is limited by complex terrain and personnel, and is low in efficiency, and the search personnel are easy to be harmed by radiation. Influenced by the rapid development of robot technology, using robots to search for radioactive sources has become an important method for nuclear emergency treatment. However, for unknown scenes, manual remote control search is still mainly used, although it avoids radiation harm to personnel, but the efficiency is still low. At the same time, although the use of robots avoids radiation harm to personnel, the radiation dose that the robot can withstand is still limited.

[0004] Therefore, a method for controlling robots to autonomously and efficiently search for radioactive sources in unknown environments with higher efficiency is needed. SUMMARY

[0005] In order to improve the above problems, the present application provides a method, device and system for autonomous search of radioactive sources in unknown environments, which not only guarantees the safety of workers, but also avoids the workers from directly searching for radioactive sources, reduces the possibility of radiation harm to the search personnel of radioactive sources, and also considers the service life of the robot in the radiation environment, reduces the absorbed dose of the robot in the search process of radioactive sources, prolongs the service life of the robot, and reduces the long-term use cost of using the robot to search for radioactive sources.

[0006] In a first aspect, the present application provides a method for autonomous search of radioactive sources in unknown environments, the method comprising:

[0007] After the robot enters the unknown radiation environment, initialization is performed;

[0008] Real-time positioning of the robot and environment map construction are performed based on SLAM technology to obtain the current position of the robot and the surrounding obstacle situation;

[0009] acquire a radiation dose rate of a current position measured by a radiation detector, and obtain an estimated result for a radioactive source according to the current position and a surrounding obstacle condition, the estimated result including a radioactive source position and activity;

[0010] judge whether the current estimated result is taken as a final radioactive source positioning result according to comparison of multiple estimated results, and determine a next moving target position of the robot;

[0011] plan a motion path of the robot by comprehensively considering a moving cost and a cumulative radiation dose cost, taking the current position of the robot as a starting point and taking the moving target position as a target point.

[0012] Optionally, the step of obtaining the estimated result for the radioactive source according to the current position and the surrounding obstacle condition specifically includes:

[0013] based on a particle filter algorithm, combining real-time positioning of the robot and an environment map, and according to a radioactive source dose rate theoretical calculation model, estimating the position and activity of the radioactive source.

[0014] Optionally, the step of judging whether the current estimated result is taken as the final radioactive source positioning result according to comparison of multiple estimated results, and determining the next moving target position of the robot specifically includes:

[0015] comparing the optimal estimated result at the current position with the two estimated results, if a difference value is within a preset threshold interval, taking the current estimated result as a final estimated result, and taking the radioactive source position in the estimated result as a next moving target; if the difference value is outside the preset threshold interval, selecting a spatial position in a safe radiation dose rate region as the next moving target.

[0016] Optionally, the method for planning the motion path of the robot is:

[0017] obtaining a moving cost map based on the constructed environment map;

[0018] searching for a cost of the robot moving from the current position to a map grid in eight surrounding directions;

[0019] selecting a grid with a minimum required cost as a new current position, recording the path, and starting a next search until the target position is searched;

[0020] backtracking all nodes from the starting point to the target point, extracting an optimal path from the current position to the target position as the planned path of the robot and outputting.

[0021] A second aspect of the embodiment of the application provides an unknown environment radioactive source autonomous search device, the device comprising:

[0022] An initialization unit is configured to control the robot to initialize after entering the unknown radiation environment;

[0023] An environment construction unit is configured to perform real-time positioning and environment map construction of the robot based on a SLAM technology, to obtain a current position of the robot and a surrounding obstacle condition;

[0024] A position estimation unit is configured to obtain a radiation dose rate of a current position measured by a radiation detector, and to obtain an estimation result for a radioactive source according to the current position and the surrounding obstacle condition, the estimation result including a position and an activity of the radioactive source;

[0025] A target determination unit is configured to determine whether a current estimation result is used as a final radioactive source positioning result based on comparison of multiple estimation results, and to determine a next moving target position of the robot;

[0026] A path planning unit is configured to plan a motion path of the robot by taking the current position of the robot as a starting point and the moving target position as a target point, and by comprehensively considering a moving cost and a cumulative radiation dose cost.

[0027] Optionally, the position estimation unit is specifically configured to:

[0028] estimate the position and the activity of the radioactive source based on a particle filter algorithm, in combination with real-time positioning and an environment map of the robot, and according to a dose rate theoretical calculation model of the radioactive source.

[0029] Optionally, the target determination unit is specifically configured to:

[0030] compare an optimal estimation result at the current position with two estimation results, if a difference value is within a preset threshold interval, use the current estimation result as a final estimation result, and use a position of the radioactive source in the estimation result as a next moving target, and if the difference value is outside the preset threshold interval, select a spatial position in a safe radiation dose rate region as the next moving target.

[0031] Optionally, the path planning unit is specifically configured to:

[0032] obtain a moving cost map based on the constructed environment map;

[0033] search for a cost of the robot moving from the current position to a map grid in eight directions around the current position;

[0034] select a grid with a minimum required cost as a new current position, record the grid into a path, and start a next search until the target position is searched;

[0035] trace all nodes from the starting point to the target point, extract an optimal path from the current position to the target position as a planned path of the robot, and output the planned path.

[0036] In a third aspect, the present application provides an unknown environment radioactive source autonomous search system, comprising a robot body, a detection system, a communication system and an intelligent processing system, wherein:

[0037] The robot body comprises a power supply system, a driving control system and a device carrying platform; the power supply system is used for powering the driving control system and the detection system, the communication system and the intelligent processing system; the driving control system is used for data exchange with the communication system and the intelligent processing system, realizing control instruction receiving and controlling the movement of the robot in space; the device carrying platform is mechanically connected with the communication system, the intelligent processing system and the detection system, realizing the installation and fixation of each part.

[0038] The intelligent processing system is used for executing the unknown environment radioactive source autonomous search method according to any one of claims 1-4.

[0039] The detection system is used for realizing the detection of the external environment.

[0040] The communication system is used for realizing the information communication among the detection system, the intelligent processing system and the driving control system.

[0041] Optionally, the detection system comprises an odometer, an acceleration sensor, an inertial sensor, a radar sensor, a visual sensor and a radiation detector, and all the sensors are electrically connected with the intelligent processing system.

[0042] Compared with the prior art, the present application has the following advantages and effects:

[0043] (1) The present application combines the SLAM technology, and can realize the search of radioactive sources in unknown environments.

[0044] (2) The environmental obstacle map is considered in the process of radioactive source search, and the radioactive sources can be searched more quickly.

[0045] (3) The environmental map influence is considered in the process of path planning, and the obstacle collision risk is optimized.

[0046] (4) The radioactive source position and activity influence are considered in the process of path planning, the absorption dose of the robot in the process of radioactive source search is reduced, the service life of the robot is prolonged, and economic losses are further reduced.

[0047] The present application replaces artificial search with mobile robots to search for radioactive sources, avoids the harm of nuclear radiation to search personnel, effectively avoids social panic and personnel casualties, and reduces economic losses. BRIEF DESCRIPTION OF DRAWINGS

[0048] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some of the embodiments of the present application, and therefore should not be regarded as a limitation to the scope, and for those skilled in the art, other related drawings can also be obtained without creative labor.

[0049] Figure 1 The method flow chart of the unknown environment radioactive source autonomous search method of the embodiment of the present application;

[0050] Figure 2 The schematic diagram of the real-time two-dimensional occupancy grid map established in the unknown environment of the embodiment of the present application;

[0051] Figure 3 The method flow chart of the motion path of the robot planned in the embodiment of the present application;

[0052] Figure 4 The constructed occupancy grid map m of the embodiment of the present application k The schematic diagram after the inflation processing.

[0053] Figure 5 The schematic diagram of the path planned by the improved A* algorithm of the embodiment of the present application.

[0054] Figure 6 The function module block diagram of the unknown environment radioactive source autonomous search device of the embodiment of the present application.

[0055] Figure 7 The schematic diagram of the architecture of the unknown environment radioactive source autonomous search system of the embodiment of the present application.

[0056] Reference signs:

[0057] Initialization unit 110; environment construction unit 120; position estimation unit 130; target determination unit 140; path planning unit 150. DETAILED DESCRIPTION

[0058] With the continuous development of nuclear industry and nuclear technology, radioactive sources and ray devices have been widely used in the fields of industry, agriculture, medical treatment, scientific research and the like, and have made important contributions to promoting economic development and social development. However, due to the particularity of radioactive substances, once out of control, it will seriously threaten the health and safety of the public. Therefore, after the occurrence of relevant accidents, the unknown position radioactive source must be searched and positioned as soon as possible

[0059] The traditional radioactive source searching method mainly relies on artificial carrying portable detection instrument to carry out inspection and searching, but is limited by complex terrain and personnel, low efficiency, and the searching personnel are easy to be harmed by radiation. Influenced by the rapid development of robot technology, using robots to search radioactive sources has become an important method for nuclear emergency treatment. However, for unknown scenes, artificial remote control search is mainly used, although the personnel radiation harm is avoided, but the efficiency is still low. At the same time, although the robot avoids the radiation harm of personnel, the radiation dose that the robot can withstand is still limited.

[0060] Therefore, a method for controlling a robot to autonomously and efficiently search for a radioactive source in an unknown environment with higher efficiency is needed.

[0061] In view of this, the designer of the present application designs a method, device and system for autonomous searching of radioactive sources in unknown environments, which not only ensures the safety of the staff, but also avoids the staff from directly searching for radioactive sources, reduces the possibility of radiation harm to the staff searching for radioactive sources, and also takes into account the service life of the robot in the radiation environment, reduces the absorbed dose of the robot in the process of searching for radioactive sources, prolongs the service life of the robot, and reduces the long-term use cost of searching for radioactive sources by using the robot.

[0062] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all the embodiments. The components of the embodiments of the present application described and shown in the drawings can be arranged and designed in various different configurations.

[0063] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed application, but only represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor are within the scope of protection of the present application.

[0064] It should be noted that: similar reference numbers and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0065] In the description of the present application, it should be noted that the terms "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the present application is usually placed, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second" and the like are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0066] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "set", "mount", "connect", "connect" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be connected inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0067] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0068] Please refer to Figure 1 The unknown environment radioactive source autonomous search method provided by an embodiment of the present application, the method comprises:

[0069] Step S101, after controlling the robot to enter the unknown radiation environment, initialization is performed.

[0070] After the robot enters the unknown radiation environment, initialization is performed, and the search system is started to work.

[0071] Step S102, real-time positioning of the robot and environment map construction based on SLAM technology are performed to obtain the current position of the robot and the surrounding obstacle situation.

[0072] SLAM refers to a simultaneous localization and mapping (Simultaneous Localization and Mapping) technology, which is a technology for accurately positioning and mapping a robot or other mobile device in an unknown environment. The principle is to obtain the data of the surrounding environment through the sensors (such as laser radar, camera, etc.) carried by the robot itself, and to realize the modeling of the environment and the positioning of the robot in this environment through algorithms. SLAM technology is widely used in robot navigation, autonomous driving, unmanned aerial vehicles and other fields, and can help robots achieve high-precision autonomous navigation and path planning. In the present embodiment, the specific type of SLAM technology used is not specifically limited, and any currently disclosed algorithm based on SLAM technology can be used to achieve the operation of the present step.

[0073] As a preferred mode of the embodiment of the present application, the specific execution mode of step S102 is as follows:

[0074] Based on the odometer and radar sensor data, a two-dimensional occupancy grid map m of the unknown environment is established in real time by the gmapping method k map , and the current position p of the radiation detector carried by the robot is determined k k k k T . The established two-grid map is shown in Figure 2

[0075] Step S103, the radiation dose rate at the current position measured by the radiation detector is obtained, and an estimated result for the radioactive source is obtained according to the current position and the surrounding obstacle condition, the estimated result including the position and activity of the radioactive source.

[0076] Wherein, the calculation method of the radiation dose rate is to measure the count rate of the position where the robot is located according to the nuclear radiation detector, and then convert it into the radiation dose rate n of the position k

[0077] The specific operation mode of step S103 is: based on the particle filtering algorithm, combining the real-time positioning of the robot and the environment map, estimating the position and activity of the radioactive source according to the dose rate theoretical calculation model of the radioactive source. That is, based on the particle filtering algorithm, combining the occupancy grid map m k map , estimating the position p of the radioactive source s and the activity A s

[0078] The operation process is as follows:

[0079] 1. Based on the particle filtering idea, N​​​​​​s A possible radioactive source as a particle, each radioactive source is set as s i i i T i i i i T and A i are the spatial position and activity of the i-th radioactive source, respectively. The particle generation mode is uniform distribution, as shown in equations (1)-(4):

[0080] x i = U[x min , x max ](1)

[0081] y i = U[y min , y max ](2)

[0082] z i = U[z min , z max ](3)

[0083] A i = U[A min , A max ](4)

[0084] 2. Set the background count rate of the space as n b , the theoretical radiation rate of the position where the robot is located can be estimated according to the following formula (5):

[0085]

[0086] Where μ i is the linear attenuation coefficient of the shielding material between p k and p i to radioactive rays, which can be pre-set or identified by the visual module according to the actual situation. d i is the distance between p k and p i through the shielding material, which is calculated according to the real-time generated grid occupancy map d i = f d (m k , p k , p i ).

[0087] 3. According to the Poisson distribution phenomenon that the detected radiation count rate in the space conforms to the theoretical radiation count rate, the radioactive source s i = p i ​​​​​​A i T , obtaining observation g k = p k , n k T The probability of g

[0088]

[0089] 4. According to the Bayesian theory, the probability that the radioactive source s k = p k , n k T is the real radioactive source when the observation g i = p i , A i T is obtained:

[0090]

[0091] 5. The N s generated radioactive source probabilities are normalized, and the minimum mean square error is taken, that is, the optimal radioactive source information estimation s k = p k , n k T under the current observation g s = p s , A s T , p s = x s , y s , z s is obtained, that is, the position of the radioactive source, and A s is the activity of the radioactive source.

[0092] Through the above process, the estimation of the position and activity of the radioactive source is completed.

[0093] Step S104, based on the comparison of multiple estimation results, determining whether the current estimation result is used as the final radioactive source positioning result, and determining the next moving target position of the robot.

[0094] When estimating the position of the radioactive source, the estimation results at multiple different positions of the robot need to be compared to determine. At the same time, multiple estimations will be performed at the same position to obtain the optimal estimation result at the current position.

[0095] As a preferred embodiment of the embodiment of the application, step S104 specifically comprises:

[0096] The optimal estimation result at the current position is compared with the two estimation results, and in general, the last two estimation results are selected for comparison. The comparison results are classified into two cases:

[0097] Case one, if the difference value is outside the preset threshold interval, a spatial position in the safe radiation dose rate region is selected as the next moving target. Case two, if the difference value is within the preset threshold interval, the current estimation result is taken as the final estimation result, and the position of the radioactive source in the estimation result is taken as the next moving target.

[0098] Specifically, for case one, if the current estimation result for the radioactive source is not the final estimation result, a spatial position p g =x g ,y g ,z k is selected as the robot moving target in the safe radiation dose rate region. The specific implementation method is as follows:

[0099] Method 1, if the radiation dose rate at the current position of the robot is lower than the radiation dose rate threshold n th , i.e., the robot is in the safe radiation dose rate range, the selected position p g needs to satisfy the conditions: (1) the radiation dose rate of the position p g is lower than the radiation dose threshold n th , and (2) cos(p s -p k , p g -p k )>0. The radiation dose rate of the position p g is calculated according to formula (5).

[0100] Method 2, if the radiation dose rate at the current position of the robot is higher than the radiation dose rate threshold n th , i.e., the robot is not in the safe radiation dose rate range, the selected position p g needs to satisfy the conditions: (1) the radiation dose rate of the position p g is lower than the radiation dose threshold n th , and (2) cos(p s -p k , p g -p k )=-π.

[0101] For case two, if the current estimation result of the radioactive source is the final estimation result, the position p g satisfies p g =x s ,y s ,z k =p s , i.e., the position of the radioactive source ps target position p g .

[0102] Step S105, taking the current position of the robot as the starting point and the moving target position as the target point, the motion path of the robot is planned by comprehensively considering the moving cost and the cumulative radiation dose cost.

[0103] After the target position p g is determined, according to the current position p k of the robot, the occupancy grid map m k , the estimated position p s of the radiation source and the activity A s , the path algorithm used in the embodiment of the present application improves the cost function f(n) of the A* algorithm. Taking the current position p k as the starting point and the target position p g as the target point, the motion path of the robot is planned by comprehensively considering the moving cost and the cumulative radiation dose cost.

[0104] As a preferred embodiment of the present application, as shown in Figure 3 , step S105 specifically includes.

[0105] Step S201, the moving cost map is obtained based on the constructed environment map.

[0106] The constructed occupancy grid map m k is dilated to obtain the occupancy cost map c k =f cost (m k ). The closer to the obstacle on the map, the higher the cost represented. The dilating effect is shown in Figure 4 .

[0107] Step S202, the cost of the robot moving from the current position to the grid in eight directions around is searched.

[0108] In the grid map, the robot searches the cost of moving from the current position p k to the grid in eight directions around in an eight-direction search manner, and the position to be searched is recorded as p n . The specific search method is as follows:

[0109] 1. Query the passable cost c n (p k ) of the grid position p n . If the passable cost c k (p n ) is greater than or equal to the fatal obstacle cost c lethal , that is, the current grid position is not passable, then skip the current search and start searching the next position.

[0110] 2. Calculate the cumulative cost of grid position p n = x n , y n , z k :

[0111] gp n = gp k + k gm g m + k gr g r (8)

[0112] where gp k is the cumulative cost of the current position, g m is the movement cost of moving from position p k to position p n , g r is the radiation cost of moving from position p k to position p n . k gm and k gr are the movement cost coefficient and the radiation dose coefficient respectively when calculating the cumulative cost, by setting the ratio of the two coefficients, the degree of inclination of the minimum movement cost and the lowest radiation dose cost in the search process can be adjusted.

[0113] g m = p n p k c k (p n ) + c k (neutral) (9)

[0114]

[0115] where p n p k represents the Euclidean distance between position p k and position p n ; c k (p n ) is the cost of position p n in the cost map; c k (neutral) is the movement cost of the robot; np k and np n are the measured radiation dose rate of position p k and the estimated radiation dose rate of position p n according to formula (5), and the radiation cost is represented by the average dose rate multiplied by the path distance.

[0116] 3. Calculate the heuristic cost of grid position p n :

[0117] hp n = k hm h m + k hr h r (11)

[0118] where h m is the movement cost from position p n to position p g , h r is the irradiation cost from position p n to position p g . k hm and k hr are the movement cost coefficient and the irradiation dose coefficient respectively in the heuristic cost calculation, by setting the ratio of the two coefficients, the heuristic effect of different costs in the search process can be adjusted.

[0119] h m = dp g , p n c k (neutral) (12)

[0120]

[0121] where dp g , p n is the Manhattan distance between position p n and position p g .

[0122] 4. Calculate the cost required to move to grid p n :

[0123] fp n = gp n + hp n (14)

[0124] Step S203, select the grid with the minimum required cost as the new current position, record it into the path, and start the next search until the target position is searched.

[0125] After searching the eight grid positions around the current position p k , select the grid with the minimum required cost as the new current position, record it into the path, and start the next search until the target position p g is searched.

[0126] Step S204, backtrack all nodes from the starting point to the target point, extract the optimal path from the current position to the target position as the planned path of the robot and output.

[0127] Backtracking all nodes, extracting the optimal path and outputting the planned path from position p k to position p g . The path planned by the improved A* algorithm used in the embodiment of the present application has the effect as shown in Figure 5 .

[0128] Through the above method steps, the radioactive source autonomous search of the robot in an unknown environment is realized.

[0129] In summary, the unknown environment radioactive source autonomous search method provided by the embodiment not only guarantees the safety of the staff and reduces the possibility of radioactive source search personnel being harmed by radiation, but also takes into account the service life of the robot in a radiation environment, reduces the absorbed dose of the robot during the radioactive source search process, prolongs the service life of the robot, and reduces the use cost of the robot for long-term search of radioactive sources.

[0130] As shown in Figure 5 , the unknown environment radioactive source autonomous search device provided by the embodiment of the present application comprises:

[0131] An initialization unit 110, configured to control the robot to enter an unknown radiation environment and perform initialization;

[0132] An environment construction unit 120, configured to perform real-time positioning and environment map construction of the robot based on a SLAM technology, and obtain a current position of the robot and surrounding obstacle conditions;

[0133] A position estimation unit 130, configured to obtain a radiation dose rate of a current position measured by a radiation detector, and obtain an estimation result for a radioactive source according to the current position and the surrounding obstacle conditions, the estimation result comprising a position and activity of the radioactive source;

[0134] A target determination unit 140, configured to compare a plurality of estimation results, determine whether a current estimation result is used as a final radioactive source positioning result, and determine a next movement target position of the robot;

[0135] A path planning unit 150, configured to take the current position of the robot as a starting point, take the movement target position as a target point, and plan a movement path of the robot by comprehensively considering a movement cost and a cumulative radiation dose cost.

[0136] As a preferred embodiment of the present embodiment, the position estimation unit 130 is specifically configured to:

[0137] Based on a particle filtering algorithm, the position and activity of the radioactive source are estimated according to a radioactive source dose rate theoretical calculation model in combination with real-time positioning and an environment map of the robot.

[0138] As a preferred embodiment of the present embodiment, the target determination unit 140 is specifically configured to:

[0139] The optimal estimation result at the current position is compared with the two estimation results, if the difference value is within the preset threshold interval, the current estimation result is taken as the final estimation result, and the position of the radiation source in the estimation result is taken as the next moving target; if the difference value is outside the preset threshold interval, a spatial position in the safe radiation dose rate region is selected as the next moving target.

[0140] As a preferred embodiment of the present embodiment, the path planning unit 150 is specifically configured to:

[0141] Obtaining a moving cost map based on the constructed environment map;

[0142] Searching the cost of the robot moving from the current position to the map grid in eight directions around;

[0143] Selecting the grid with the minimum required cost as the new current position, recording it into the path, and starting the next search until the target position is searched;

[0144] Backtracking all nodes from the starting point to the target point, extracting the optimal path from the current position to the target position as the planned path of the robot and outputting.

[0145] The unknown environment radioactive source autonomous search device provided by the embodiment of the present application is used to realize the unknown environment radioactive source autonomous search method described above, so the specific implementation manner is the same as the method described above, and will not be repeated here.

[0146] As shown in Figure 6 The unknown environment radioactive source autonomous search system provided by the embodiment of the present application includes a robot main body, a detection system, a communication system and an intelligent processing system, wherein:

[0147] The robot main body includes a power supply system, a driving control system and a device carrying platform; the power supply system is used to supply power for the driving control system and the detection system, the communication system and the intelligent processing system; the driving control system is used to exchange data with the communication system and the intelligent processing system, realize control instruction receiving, and control the movement of the robot in space; the device carrying platform is mechanically connected with the communication system, the intelligent processing system and the detection system, realizes the installation and fixation of each part;

[0148] The intelligent processing system is used for executing the unknown environment radioactive source autonomous search method; the intelligent processing system is fixed to the robot body, and is electrically connected with the robot body, the communication system and the detection system. It receives and processes the detection system data, realizes the real-time positioning of the robot in the unknown environment and the environment map construction, plans the motion path of the robot based on the constructed environment map and the environmental obstacles and radiation dose, and finally completes the radioactive source search task.

[0149] The detection system is used for realizing the detection of the external environment.

[0150] The communication system is used for realizing the information communication among the detection system, the intelligent processing system and the driving control system. The communication system is electrically connected with the robot body and the intelligent processing system, can be guided by a human being in the search process of the robot through a remote terminal, and can realize the direct control of the robot motion by the remote terminal when necessary.

[0151] As a preferred embodiment of the embodiment, the detection system comprises an odometer, an acceleration sensor, an inertial sensor, a radar sensor, a visual sensor and a radiation detector, and all the sensors are electrically connected with the intelligent processing system.

[0152] In summary, the application provides an unknown environment radioactive source autonomous search method, device and system. Compared with the currently used method, the safety of the staff is ensured, the possibility of radiation injury of the radioactive source search personnel is reduced, the service life of the robot in the radiation environment is considered, the absorbed dose of the robot in the radioactive source search process is reduced, the service life of the robot is prolonged, and the use cost of the robot for long-term search of the radioactive source is reduced.

[0153] In several embodiments disclosed in the present application, it should be understood that the disclosed apparatus and method can also be implemented in other manners. The described apparatus embodiments are merely illustrative. For example, the flowchart and block diagram in the accompanying drawings show the possible implementation architecture, function and operation of the apparatus, method and computer program product according to the embodiments of the present application. In this regard, each block in the flowchart or block diagram can represent a module, a segment or a portion of code which comprises one or more executable instructions for implementing the specified logic function. It should also be noted that in some alternative implementations, the functions shown in the blocks can occur in a different order than that shown in the figure. For example, two blocks shown in succession can in fact be executed substantially concurrently or in the reverse order, depending on the functionality involved. It should also be noted that each block in the block diagrams and / or flowchart illustrations, and combinations of blocks in the block diagrams and / or flowchart illustrations, can be implemented by dedicated hardware-based systems which perform the specified functions or acts or can be implemented by a combination of dedicated hardware and computer instructions.

[0154] In addition, the various functional modules in the embodiments of the present application can be integrated together to form a separate part, or each module can exist independently, or two or more modules can be integrated to form a separate part.

[0155] If the functions are implemented in the form of software function modules and sold or used as an independent product, they can be stored in a computer readable storage medium. Based on this understanding, the technical solutions of the present application essentially or the part that makes a contribution to the prior art or the part of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes a number of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the embodiments of the present application. The aforementioned storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a magnetic disk or an optical disk, and various other media that can store program codes.

Claims

1. A method for autonomously searching for radioactive sources in unknown environments, characterized in that, The method includes: After the robot enters an unknown radiation environment, it is initialized. Real-time localization and environmental mapping of robots are performed based on SLAM technology to obtain the robot's current position and the situation of surrounding obstacles; The radiation dose rate at the current location is obtained from the radiation detector, and an estimation result for the radiation source is obtained based on the current location and the surrounding obstacles. The estimation result includes the location and activity of the radiation source. Based on the comparison of multiple estimation results, it is determined whether the current estimation result should be used as the final radiation source location result, and the next target location of the robot is determined. Starting from the robot's current position and targeting the desired location, the robot's motion path is planned by comprehensively considering the movement cost and the cumulative radiation dose cost. The method for planning the robot's motion path is as follows: A movement cost map is obtained based on the constructed environment map; the constructed occupation grid map is then processed. Perform an expansion process to obtain a map of the cost of occupation. On the map, the closer a grid is to an obstacle, the higher the cost. In the grid map, the robot uses an eight-directional search method, starting from its current position. The cost of moving to the surrounding eight grid cells, denoted as the position of the grid cell to be searched. Specific search methods include: querying raster positions. Passable cost If it is passable, the cost Greater than or equal to the cost of a fatal obstacle If the current grid position is impassable, skip the current search and start searching for the next position; calculate the grid position. Cumulative cost: ;in, The cumulative cost for the current position. From position Move to position The cost of movement, From position Move to position The cost of radiation exposure; and These are the movement cost coefficient and radiation dose coefficient used in the cumulative cost calculation, respectively. By setting the ratio of these two coefficients, the tendency of the minimum movement cost and the minimum radiation dose cost during the search process can be adjusted. ; ;in, Indicates position With position The Euclidean distance; For position Costs in the cost map; The cost of robot movement; and Positions Measured radiation dose rate and location Radiation dose rate; calculate grid position The cost of inspiration: ;in, From position Move to position The cost of movement, From position Move to position The cost of radiation exposure; and These are the mobility cost coefficient and radiation dose coefficient used in heuristic cost calculation, respectively; ; ;in For position With position Manhattan distance between; calculate movement to grid Cost required: ； After searching the current location After searching eight surrounding grid positions, select the grid with the lowest cost as the new current position, record it in the path, and start the next search until the target position is found. Backtrack through all nodes, extract the optimal path, and output the path starting from the initial position. To the target location The planned path.

2. The autonomous search method for radioactive sources in unknown environments according to claim 1, characterized in that, The step of obtaining the estimation result for the radiation source based on the current location and surrounding obstacles specifically includes: Based on the particle filter algorithm, combined with the robot's real-time localization and environmental map, the location and activity of the radioactive source are estimated according to the theoretical calculation model of the radioactive source dose rate.

3. The autonomous search method for radioactive sources in unknown environments according to claim 2, characterized in that, The step of determining whether the current estimation result should be used as the final radiation source location result based on the comparison of multiple estimation results, and determining the next target location for the robot's movement, specifically includes: The best estimate at the current location is compared with the two estimates. If the difference is within a preset threshold range, the current estimate is taken as the final estimate, and the location of the radiation source in the estimate is taken as the next target. If the difference is outside the preset threshold range, a spatial location within the safe radiation dose rate range is selected as the next target.

4. The autonomous search method for radioactive sources in unknown environments according to claim 3, characterized in that, The method for planning the robot's motion path is as follows: A movement cost map is obtained based on the constructed environment map; The cost of a search robot moving from its current location to map grids in eight directions; Select the grid cell with the lowest required cost as the new current position, record it in the path, and start the next search until the target position is found; Backtrack all nodes from the starting point to the target point, extract the optimal path from the current position to the target position as the robot's planned path and output it.

5. An autonomous search device for radioactive sources in unknown environments, characterized in that, The device includes: The initialization unit is used to initialize the robot after it enters an unknown radiation environment. The environment building unit is used for real-time localization and environmental mapping of the robot based on SLAM technology, and to obtain the robot's current position and the surrounding obstacles. The position estimation unit is used to obtain the radiation dose rate at the current position measured by the radiation detector, and to obtain an estimation result for the radiation source based on the current position and the surrounding obstacles. The estimation result includes the position and activity of the radiation source. The target determination unit is used to determine whether the current estimation result should be used as the final radiation source localization result based on the comparison of multiple estimation results, and to determine the target position for the robot's next movement. The path planning unit is used to plan the robot's motion path, taking into account both the movement cost and the cumulative radiation dose cost, starting from the robot's current position and moving to the target position. The path planning unit is specifically used for: A movement cost map is obtained based on the constructed environment map; the constructed occupation grid map is then processed. Perform an expansion process to obtain a map of the cost of occupation. On the map, the closer a grid is to an obstacle, the higher the cost. In the grid map, the robot uses an eight-directional search method, starting from its current position. The cost of moving to the surrounding eight grid cells, denoted as the position of the grid cell to be searched. Specific search methods include: querying raster positions. Passable cost If it is passable, the cost Greater than or equal to the cost of a fatal obstacle If the current grid position is impassable, skip the current search and start searching for the next position; calculate the grid position. Cumulative cost: ;in, The cumulative cost for the current position. From position Move to position The cost of movement, From position Move to position The cost of radiation exposure; and These are the movement cost coefficient and radiation dose coefficient used in the cumulative cost calculation, respectively. By setting the ratio of these two coefficients, the tendency of the minimum movement cost and the minimum radiation dose cost during the search process can be adjusted. ; ;in, Indicates position With position The Euclidean distance; For position Costs in the cost map; The cost of robot movement; and Positions Measured radiation dose rate and location Radiation dose rate; calculate grid position The cost of inspiration: ;in, From position Move to position The cost of movement, From position Move to position The cost of radiation exposure; and These are the mobility cost coefficient and radiation dose coefficient used in heuristic cost calculation, respectively; ; ;in For position With position Manhattan distance between; calculate movement to grid Cost required: ； After searching the current location After searching eight surrounding grid positions, select the grid with the lowest cost as the new current position, record it in the path, and start the next search until the target position is found. Backtrack through all nodes, extract the optimal path, and output the path starting from the initial position. To the target location The planned path.

6. The autonomous search device for radioactive sources in unknown environments according to claim 5, characterized in that, The location estimation unit is specifically used for: Based on the particle filter algorithm, combined with the robot's real-time localization and environmental map, the location and activity of the radioactive source are estimated according to the theoretical calculation model of the radioactive source dose rate.

7. The autonomous search device for radioactive sources in unknown environments according to claim 6, characterized in that, The target determination unit is specifically used for: The best estimation result at the current location is compared with the two estimation results. If the difference is within the preset threshold range, the current estimation result is taken as the final estimation result, and the location of the radiation source in the estimation result is taken as the next moving target. If the difference value is outside the preset threshold range, a spatial location within the safe radiation dose rate range will be selected as the next moving target.

8. The autonomous search device for radioactive sources in unknown environments according to claim 7, characterized in that, The path planning unit is specifically used for: A movement cost map is obtained based on the constructed environment map; The cost of a search robot moving from its current location to map grids in eight directions; Select the grid cell with the lowest required cost as the new current position, record it in the path, and start the next search until the target position is found; Backtrack all nodes from the starting point to the target point, extract the optimal path from the current position to the target position as the robot's planned path and output it.

9. An autonomous search system for radioactive sources in unknown environments, characterized in that, It includes the robot body, detection system, communication system, and intelligent processing system, among which: The robot body includes a power system, a drive control system, and an equipment mounting platform. The power system provides power to the drive control system, detection system, communication system, and intelligent processing system. The drive control system communicates with the communication system and intelligent processing system to receive control commands and control the robot's movement in space. The equipment mounting platform is mechanically connected to the communication system, intelligent processing system, and detection system to secure the various components. The intelligent processing system is used to execute the autonomous search method for radioactive sources in unknown environments as described in any one of claims 1-4; The detection system is used to detect the external environment; The communication system is used to enable information communication between the detection system, the intelligent processing system, and the drive control system.

10. The autonomous search system for radioactive sources in unknown environments according to claim 9, characterized in that, The detection system includes an odometer, an accelerometer, an inertial sensor, a radar sensor, a visual sensor, and a radiation detector. All sensors are electrically connected to the intelligent processing system.

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