A global path planning method and system for a weld detection wall-climbing robot

Abstract

The present invention discloses a global path planning method and system for a weld detection wall-climbing robot, which relates to the path planning of the welds of a petrochemical storage tank. The method includes: establishing the kinematic modeling of the wall-climbing robot; mapping the three-dimensional weld stripes of the storage tank to be detected onto a two-dimensional plane to create a weld two-dimensional plane map; classifying and numbering the intersection points on the two-dimensional plane map and calibrating the length weights of the welds, and at the same time dividing the detection areas; using the classification and numbering of the intersection points on the two-dimensional plane map, the length weights of the welds and the detection areas to establish a mathematical model of the path information of the two-dimensional plane map; and solving the mathematical model of the path information under the two constraints of traversing all the welds and the shortest path to obtain the optimal path. The present invention can greatly improve the efficiency of planning the shortest path of the global optimal path of the robot.

Description

Technical Field

[0001] The present invention relates to the weld path planning of petrochemical storage tanks, and particularly to a global path planning method and system for a wall-climbing robot for weld detection. Background Art

[0002] Petrochemical storage tanks are important tools for storing and transporting dangerous goods such as petroleum and natural gas. The tank body is welded by steel plates, and there are many welds on its inner wall. After long-term corrosion and impact, defects such as pores and cracks will appear on the weld surface. Weld defects in petrochemical storage tanks can cause oil leakage at worst and explosion at worst. Therefore, it is necessary to regularly detect the welds. The traditional method for detecting the inner wall welds of petrochemical storage tanks is for workers to carry detection tools into the tank for inspection. This method not only has low detection efficiency and high missed detection rate, but also the working environment poses great harm to the health of the detection personnel. In recent years, with the continuous development of robot technology. In the field of petrochemical industry, it has become a major trend for wall-climbing robots to replace humans to enter various storage tanks to complete detection operations. To enable the robot to quickly and efficiently complete the detection task, first, a global optimal path needs to be planned for the robot. Under the condition of the optimal path, ensure that the robot can accurately complete the detection according to the planned path. Different from the path planning of ordinary mobile robots, the path distribution of this three-dimensional tank detection robot is a three-dimensional map, and at the same time, it has two constraint conditions: traversing all welds and the shortest path. There are a large number of intersections and obstacles in the map. Therefore, the map must be simplified and a reasonable model must be established for solution.

[0003] Most of the existing path planning methods for wall-climbing robots are only applicable to ordinary two-dimensional plane mobile robots. When encountering a three-dimensional complex environment, many methods are not applicable. And most of the research is for the global path planning of the optimal path from point to point or the full traversal of the environment. There are relatively few global path planning methods for solving the two-constraint problem of passing through all known routes and having the shortest path. Summary of the Invention

[0004] Aiming at the deficiencies in the prior art, the present invention provides a global path planning method and system for a wall-climbing robot for weld detection, which can solve the global path planning problem with two constraint conditions of traversing all welds and the shortest path in the case of a large number of intersections and obstacles in three-dimensional path planning, and can greatly improve the efficiency of planning the shortest path of the global optimal path of the robot.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] In the first aspect, the present invention provides a global path planning method for a wall-climbing robot for weld detection, which includes:

[0007] Establish the kinematic modeling of the wall-climbing robot;

[0008] Map the three-dimensional weld stripes of the storage tank to be detected onto a two-dimensional plane, thereby creating a two-dimensional plane map of the welds;

[0009] Classify, number, and calibrate the length weights of the welds for the intersection points on the two-dimensional plane map, and at the same time divide the detection area;

[0010] Utilize the classification, numbering, length weights of the welds, and the detection area of the intersection points on the two-dimensional plane map to establish a mathematical model of the path information of the two-dimensional plane map;

[0011] Under the two constraints of traversing all welds and the shortest path, solve the mathematical model of the path information to obtain the optimal path.

[0012] In a second aspect, the present invention provides a global path planning system for a weld detection wall-climbing robot, which includes:

[0013] A first processor, which is used to establish the kinematic modeling of the wall-climbing robot;

[0014] A second processor, which is used to map the three-dimensional weld stripes of the storage tank to be detected onto a two-dimensional plane, thereby creating a two-dimensional plane map of the welds;

[0015] A third processor, which is used to classify, number, and calibrate the length weights of the welds for the intersection points on the two-dimensional plane map, and at the same time divide the detection area;

[0016] A fourth processor, which is used to utilize the classification, numbering, length weights of the welds, and the detection area of the intersection points on the two-dimensional plane map to establish a mathematical model of the path information of the two-dimensional plane map;

[0017] A fifth processor, which is used to solve the mathematical model of the path information under the two constraints of traversing all welds and the shortest path to obtain the optimal path.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0019] (1) The present invention constructs a global path planning system and method for a three-dimensional inner wall weld detection robot of a storage tank. It realizes "rapid mapping of a two-dimensional weld map → rapid creation of a weld node mathematical model → improved shortest path planning algorithm → rapid global path planning" for the crawling detection robot, and supports the real-time online planning of the shortest path of the online detection robot.

[0020] (2) The present invention proposes a method for calculating the weight value wt(Li) of the robot walking path based on the weld path length, improves the calculation method of the cost value f(n) and the node search strategy of the A* algorithm, solves the two-constraint global path planning problem of full traversal of welds and the shortest path, has fast algorithm development and low complexity, and can quickly iterate the shortest path for the wall-climbing inspection robot. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0022] Figure 1 It is a schematic diagram of the mapping relationship of the weld map of the petrochemical storage tank in the embodiment of the invention. Figure 1 (a) is a diagram of the three-dimensional distribution model of the weld. Figure 1 (b) is a two-dimensional map of the weld distribution.

[0023] Figure 2 It is a map of the distribution of weld lines and intersection points in the embodiment of the invention.

[0024] Figure 3 It is a schematic diagram of the weld node model in the embodiment of the invention.

[0025] Figure 4 It is a flow chart of the iteration of the path planning algorithm in the embodiment of the invention.

[0026] Figure 5 It is a diagram of the global path planning result in the embodiment of the invention. Figure 5 (a) is a connected graph of the shortest path. Figure 5 (b) is a diagram of the two-dimensional map result of the shortest path.

[0027] Figure 6 It is a flow chart of the method for the global path planning method of the wall-climbing robot in the embodiment of the invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0028] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present application.

[0029] Embodiment:

[0030] It should be noted that the terms "first", "second", etc. in the description, claims and above-mentioned drawings of the present invention are used to distinguish similar objects, and do not necessarily describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" in the embodiments of the present invention and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device including a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0031] The global path planning method proposed by the present invention is applied to a crawling robot for detecting all complex intersecting welds on the inner wall surface of large storage tanks, to find a shortest detection path for the two-wheel differential crawling robot to traverse all welds, and accurately complete the detection task according to the planned path. It can be understood that reasonable path planning can improve the detection efficiency. Since the distribution of welds on petrochemical storage tanks is all known, this planning belongs to offline path planning. Different from the path planning of mobile robots in ordinary two-dimensional working environments, the path distribution of this problem is a three-dimensional environment, and at the same time, it is necessary to meet two constraints: traversing all welds and the shortest path, and there are intersection points and obstacles of partitions between welds. Therefore, it is necessary to simplify the three-dimensional map and establish a reasonable mathematical model of weld information for solution.

[0032] Furthermore, the present invention first proposes a method for creating a two-dimensional map of welds, and then proposes an improved calculation method and search strategy for the cost value f(n) of the A* algorithm to plan the global shortest path for the robot. The specific process includes: 1) quickly map the three-dimensional weld stripes to a two-dimensional plane to create a two-dimensional plane map of welds; 2) propose a method for sorting weld stripes based on weight accumulation to establish a weld mathematical model; 3) propose a region division method to find the shortest path, reduce the number of iterations, and efficiently plan the shortest path; 4) by establishing an Openlist() node set and a Closelist() node set, and then improving the calculation method of the cost value f(n) of the A* algorithm and the node search strategy, reduce the number of iterations, and can quickly plan the shortest global route.

[0033] See Figure 6 , a global path planning method for a wall-climbing robot for detecting welds on large storage tanks, may include the following steps:

[0034] Step 1: Establish the kinematic modeling of the wall-climbing robot.

[0035] In this step, for the wall-climbing robot to complete the traversal inspection of the inner wall welds of the storage tank, it is necessary to analyze its motion state and the forces acting on it during motion, so as to plan the inspection path and control the robot. In the embodiments of the present invention, the robot is regarded as a rigid body during the analysis of the crawling inspection robot, and lateral slip is not considered.

[0036] Step 2: Map the three-dimensional weld stripes of the storage tank to be inspected onto a two-dimensional plane, thereby creating a two-dimensional plane map of the welds.

[0037] In this step, since the welds of large storage tanks are three-dimensional maps in the absolute coordinate system, in order to plan the shortest path, the relative position relationship between the welds and the lengths of the welds need to be found first, and the shortest path for the robot is found through algorithm iteration. Therefore, the first thing to solve is to map the welds on the petrochemical storage tank to a two-dimensional plane map. In the embodiments of the present invention, the two-dimensional equivalent expansion method is used to equivalently transform the curved annular welds onto a two-dimensional plane, thereby quickly establishing a two-dimensional plane map; then, based on the two-dimensional plane map of the welds, the planning of the weld inspection path is carried out.

[0038] As Figure 1 (a) shows, the inspection object in the embodiments of the present invention is a large petrochemical storage tank. Specifically, the tank body is welded by annular steel plates. When welding the annular cylinder into the tank body, baffles are welded inside the tank body, and through holes are opened in the baffles. The through holes are the only channels for the inspection robot to enter the interior.

[0039] In view of the above analysis, the weld information of the tank body is converted into Figure 1 (b) shows the two-dimensional plane map. The thick black lines are the welds; the light black lines of the partitions are the shortest paths connecting the areas at both ends of the through holes, that is, the paths that the robot can walk; the dotted lines are the baffles in the tank body; in addition, the large black dots represent the starting point of the robot, which is also the end point; the hollow dots are the through holes of the baffles, indicating passable; the small black dots represent the intersection points of the welds and the baffles, indicating impassable here. Thus, the three-dimensional route is converted into a two-dimensional route.

[0040] Step 3: Classify, number and calibrate the length weights of the intersection points on the two-dimensional plane map, and at the same time divide the inspection area.

[0041] In this step, then it is necessary to classify, number and calibrate the length weights of the welds and intersection points on the two-dimensional plane map to facilitate subsequent algorithm iteration. Among them, the intersection points are divided into ring weld break points A n , obstacle points B n , passable points C n (at the baffle opening), weld intersection points D n , weld and path intersection points E n , and the marking results are as Figure 2As shown in the figure. Since the surface distance between nodes is different from the spatial Euclidean distance, there will be errors when using the traditional path planning algorithm based on the spatial Euclidean distance between nodes to calculate the optimal surface path. Therefore, after unfolding, the proposed weld length will be weighted, and the relationship between the weight values et() of each weld length satisfies Equation (1).

[0042] A1A1 = A2A2 = A3A3 = A4A4 > B1B2 > D1B1 = B2D4 > D3B2 = B1D2 (1)

[0043] In addition, to reduce the number of algorithm iterations in the later stage, improve the path planning efficiency, and reduce the repetition rate. The embodiment of the present invention will adopt the "proximity principle", divide the detection area into Area I, Area II, and Area III, and plan and connect them one by one.

[0044] Step 4: Use the classification and numbering of intersections on the two-dimensional plane map, the length weights of welds, and the detection area to establish a mathematical model of the path information of the two-dimensional plane map.

[0045] In this step, the embodiment of the present invention is not a simple point-to-point optimal path problem, but a problem similar to the "Chinese postman problem on an undirected graph". Among them, the postman starts from the post office, in order to complete the delivery of letters, walks through all the streets in the area and returns to the post office. How to walk to make the journey the shortest. The constraint conditions include traversing all weld paths and the shortest path.

[0046] Based on this, the description of this path planning problem in graph theory language is as follows:[[]]END]]

[0047] Let the undirected connected graph H = {L n , E, wt(L i )}, all the edges L i form the set network E, the path weight value wt(L i ) of the robot walking is uniformly calculated from the weld length, and wt(L i ) ≥ 0, find a path π that contains all edges, and Σ a∈L wt(L i ) is the smallest.

[0048] 1) First, we analyze the two-dimensional map, calculate and label the weights of the welds. Since the dotted line in the map is the non-passable area, from Area I to Area II, and from Area II to Area III, it can only pass through the baffle opening (C).

[0049] 2) Only the calibrated straight lines on the two-dimensional plane map can be walked between each point (required by the shortest path), and the corresponding weights are accumulated.

[0050] 3) Establish a mathematical model of the weld stripe nodes as Figure 3 , and through algorithm iteration, find Σ a∈Lwt(L i )The minimum series order is the shortest path π.

[0051] Step 5: Under the two constraints of traversing all weld seams and the shortest path, solve the mathematical model of the path information to obtain the optimal path.

[0052] In this step, after establishing the mathematical model of the weld seam nodes, an appropriate method for finding short paths needs to be proposed for iteration, and then the global path planning of the wall-climbing robot is completed. Specifically, by analyzing the advantages and disadvantages of existing methods, the application of the A* algorithm is more flexible and the convergence speed is fast. The embodiment of the present invention proposes to improve the A * algorithm for the optimal path planning method of full traversal of weld seams of the wall-climbing inspection robot.

[0053] Among them, in the embodiment of the present invention, the starting point and the ending point of the path are set to the same point. Then, calculate the cost value f(n) of each weld seam node Ln to the starting point and the ending point. The comprehensive priority of a single node in the A* algorithm is determined by formula (2).

[0054] f(n) = g(n) + h(n) (2)

[0055] In the formula, f(n) is the comprehensive priority of the weld seam node Ln; g(n) is the minimum cost of the node Ln from the starting point; h(n) is the minimum cost of the node Ln from the ending point. In the embodiment of the present invention, g(n) and h(n) are respectively calculated by calculating the minimum weight values of the current weld seam node to the starting point and the ending point, and can be calculated by formula (3). Further, estimating the cost value of the node to the target point through the Euclidean distance can meet the requirements of the shortest path, so as to obtain the shortest path weight Σ a∈L wt(L i ). Furthermore, after planning the shortest path through algorithm iteration, the robot returns to the ending point according to the set route, as Figure 5 shown, Figure 5 shows the illustration of the global path planning result in the embodiment of the invention, Figure 5 (a) shows the shortest path connection graph, Figure 5 (b) shows the illustration of the shortest path two-dimensional map result.

[0056] g(n) = h(n) = ∑ a∈L wt(L i-1 ) (3)

[0057] In the above embodiment, as Figure 4 shown, the specific algorithm iteration method is:

[0058] Step 101: Create an open list and a closed list,

[0059] Step 102: Put all nodes Ln into the open list and determine whether the open list is empty;

[0060] Step 103: Determine whether the open list is empty. If it is, jump to execute Step 108; if not, execute Step 104;

[0061] Step 104: Put the node with the smallest f(n) in the open list into the closed list;

[0062] Step 105: Determine whether f(n) is empty. If it is, execute Step 106; if not, return to execute Step 104;

[0063] Step 106: Determine whether the open list is empty. If it is, execute Step 107; if not, return to execute Step 104;

[0064] Step 107: Return to the starting point according to the pre-set route.

[0065] Step 108: End the iteration.

[0066] In summary, the global path planning method proposed by the present invention is applied to a crawling robot for the detection task of all complex intersecting welds on the inner wall surface of large storage tanks, to find the shortest detection path for a two-wheel differential crawling robot to traverse all welds, and accurately complete the detection task according to the planned path. Reasonable path planning can improve the detection efficiency. Since the distribution of welds on petrochemical storage tanks is all known, this planning belongs to offline path planning. Different from the path planning of mobile robots in ordinary two-dimensional working environments, the path distribution of this problem is in a three-dimensional environment, and at the same time, it is necessary to meet the two constraints of traversing all welds and the shortest path, and there are intersection points and obstacles of partitions between welds. Therefore, it is necessary to simplify the three-dimensional map and establish a reasonable mathematical model of weld information for solution.

[0067] Furthermore, the present invention constructs a global path planning system and method for a three-dimensional inner wall weld detection robot of a tank. It realizes "rapid mapping of a two-dimensional weld map → rapid creation of a weld node mathematical model → improvement of the shortest path planning algorithm → rapid global path planning" for the crawling detection robot, and supports the real-time online planning of the shortest path of the online detection robot. In addition, the present invention proposes a calculation method for the robot walking path weight wt(Li) based on the weld path length, improves the calculation method of the cost value f(n) and the node search strategy of the A* algorithm, solves the two-constraint global path planning problem of weld full traversal and the shortest path, has fast algorithm development and low magnitude, and can quickly iterate the shortest path for the wall-climbing detection robot.

[0068] Furthermore, the global path planning system and method for the three-dimensional tank wall-climbing robot proposed by the present invention solve the problem that the existing path planning methods are not applicable to solving the two-constraint problem of passing through all known routes and having the shortest path, and can quickly map the three-dimensional map information to a two-dimensional plane; establish a mathematical model of the map path. This will greatly improve the planning efficiency of the global path and has important scientific and engineering significance.

[0069] Based on the same inventive concept, an embodiment of the present invention further provides a global path planning system for a wall-climbing robot for detecting welds of large storage tanks, which includes a first processor, a second processor, a third processor, a fourth processor, and a fifth processor. Specifically, the first processor is used to establish the kinematic modeling of the wall-climbing robot; the second processor is used to map the three-dimensional weld stripes of the storage tank to be detected onto a two-dimensional plane to create a weld two-dimensional plane map; the third processor is used to classify and number the intersections on the two-dimensional plane map and calibrate the length weights of the welds, and at the same time divide the detection area; the fourth processor is used to establish a mathematical model of the path information of the two-dimensional plane map by using the classification and numbering of the intersections on the two-dimensional plane map, the length weights of the welds, and the detection area; the fifth processor is used to solve the mathematical model of the path information under the two constraints of traversing all welds and the shortest path to obtain the optimal path.

[0070] Since this system is the system corresponding to the global path planning method for the wall-climbing robot for detecting welds of large storage tanks in the embodiment of the present invention, and the principle of solving problems by this system is similar to that of this method, the implementation of this system can refer to the implementation process of the above method embodiment, and the repeated parts will not be described again.

[0071] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0072] The above embodiments are only for illustrating the technical concept and characteristics of the present invention, and their purpose is to enable ordinary technicians in the art to understand the content of the present invention and implement it accordingly, and cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the essence of the content of the present invention should be covered by the protection scope of the present invention.

Claims

1. A global path planning method for a weld detection wall-climbing robot, characterized in that, including: establishing the kinematic modeling of the wall-climbing robot; mapping the three-dimensional weld stripes of the storage tank to be detected onto a two-dimensional plane, thereby creating a two-dimensional plane map of the weld; Classify and number the intersection points on the two-dimensional plane map and calibrate the length weights of the welds, and at the same time divide the detection area; among them, the intersection points include the starting point, the ending point, and the circumferential weld break point A n , the obstacle point B n , the passable point C n , the passable point C n , the weld intersection point D n , the weld and path intersection point E n ; the length weight of the weld is determined by the weld length; establishing a mathematical model of the path information of the two-dimensional plane map by using the classification and numbering of the intersection points, the length weights of the welds, and the detection areas on the two-dimensional plane map; solving the mathematical model of the path information under the two constraints of traversing all welds and the shortest path to obtain the optimal path.

2. The global path planning method of the weld inspection wall-climbing robot according to claim 1, characterized in that When establishing the kinematic modeling of the wall-climbing robot, the wall-climbing robot is regarded as a rigid body and lateral slip is not considered.

3. The global path planning method of the weld detection wall-climbing robot according to claim 1, characterized in that The paths on the two-dimensional plane map include welds, paths where the robot can walk, and paths where the robot cannot walk; the divided detection areas are connected in series one by one in the vicinity.

4. The global path planning method of the weld inspection wall-climbing robot according to claim 1, characterized in that The mathematical model of path information for a two-dimensional planar map includes: an undirected connected graph H = {L n, E, wt(L i )}, all paths L i form the set network E, L n is a weld node, and the weight wt(L i ) of the path traveled by the wall-climbing robot is uniformly calculated from the weld length, and wt(L i ) ≥ 0. Find a path π that includes all paths L i , and Σ Li∈E wt(L i ) is minimized. Among them, the divided detection area can only pass through passable points; only the straight lines marked on the two-dimensional planar map can be walked between each point, and the corresponding weights are accumulated, and through iteration by the algorithm, find the Σ Li∈E wt(L i ) minimum series order, which is the shortest path π.

5. The global path planning method for the weld seam detection wall-climbing robot according to claim 4, wherein Set the starting point and the ending point of the path to the same point, and then use the A* algorithm to calculate the comprehensive priority f(n) of each weld node Ln to the starting point and the ending point. The comprehensive priority of a single node in the A* algorithm is determined by the following formula: f(n) = g(n) + h(n) In the formula, f(n) is the comprehensive priority of the weld node Ln; g(n) is the minimum cost of the node Ln from the starting point; h(n) is the minimum cost of the node Ln from the ending point; g(n) and h(n) calculate the minimum weights of the current weld node to the starting point and the ending point respectively through the following formulas: g(n) = h(n) = ∑ Li∈E wt(L i-1 )。 6. A global path planning system for a weld inspection wall-climbing robot, characterized in that, including: a first processor for establishing the kinematic modeling of the wall-climbing robot; a second processor for mapping the three-dimensional weld stripes of the storage tank to be detected onto a two-dimensional plane, thereby creating a two-dimensional plane map of the weld; A third processor, which is configured to classify and number the intersection points on the two-dimensional plane map and calibrate the length weights of the weld seams, and at the same time divide the detection area; wherein the intersection points include starting points, ending points, and circumferential weld break points A n , obstacle points B n , passable points C n , passable points C n , weld intersection points D n , weld and path intersection points E n ; the length weight of the weld seam is determined by the weld seam length; a fourth processor for establishing a mathematical model of the path information of the two-dimensional plane map by using the classification and numbering of the intersection points, the length weights of the welds, and the detection areas on the two-dimensional plane map; a fifth processor for solving the mathematical model of the path information under the two constraints of traversing all welds and the shortest path to obtain the optimal path.

7. The global path planning system of the weld detection wall-climbing robot according to claim 6, characterized in that, When establishing the kinematic modeling of the wall-climbing robot, the wall-climbing robot is regarded as a rigid body and lateral slip is not considered.

8. The global path planning system of the weld detection wall-climbing robot according to claim 6, characterized in that The paths on the two-dimensional plane map include welds, paths where the robot can walk, and paths where the robot cannot walk; the divided detection areas are connected in series one by one in the vicinity.

9. The global path planning system of the weld detection wall-climbing robot according to claim 6, characterized in that The mathematical model of path information for a two-dimensional planar map includes: an undirected connected graph H = {L n, E, wt(L i )}, all paths L i constitute the set network E, L n is a weld node, and the weight value wt(L i ) of the path traversed by the wall-climbing robot is uniformly calculated from the weld length, and wt(L i ) ≥ 0. Find a path π that includes all paths L i , and Σ Li∈E wt(L i ) is the smallest. Among them, the divided detection area can only pass through passable points; only the straight lines marked on the two-dimensional planar map can be walked between each point, and the corresponding weight values are accumulated. Through algorithm iteration, find the Σ Li∈E wt(L i ) with the smallest serial order, which is the shortest path π.

10. The global path planning system of the weld detection wall-climbing robot according to claim 9, characterized in that, Set the starting point and the ending point of the path to the same point, and then use the A* algorithm to calculate the comprehensive priority f(n) of each weld node Ln to the starting point and the ending point. The comprehensive priority of a single node in the A* algorithm is determined by the following formula: f(n) = g(n) + h(n) In the formula, f(n) is the comprehensive priority of the weld node Ln; g(n) is the minimum cost of the node Ln from the starting point; h(n) is the minimum cost of the node Ln from the ending point; g(n) and h(n) calculate the minimum weights of the current weld node to the starting point and the ending point respectively through the following formulas: g(n) = h(n) = ∑ Li∈E wt(L i-1 )。

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