Method, device and equipment for movement path planning of welding robot

Abstract

The application discloses a kind of welding robot moving path planning method, device and equipment, the method includes: based on cable key point position coordinate construction cable model, the current position coordinate of welding robot is as starting node, starting node and adjacent node are added to open list, current node that meets cost condition is screened out from open list, cable model is updated based on the position coordinate of current node;Current node is added to closed list, the adjacent node of current node is added to open list, the step of screening current node is repeatedly executed, until current node is target node;Traversal closed list, generate moving path according to the parent-child relationship between each node, realize the path of shorter cable length is planned in the case of satisfying cable restriction, effectively improve the versatility and flexibility of welding robot, avoid cable winding and length limited problem, greatly improve welding efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of welding robots, in particular to a moving path planning method, device and equipment of a welding robot. BACKGROUND

[0002] Welding process is one of the core processes in manufacturing industry, which is widely used in automobile manufacturing, shipbuilding, aerospace equipment production, steel structure engineering and many other fields. However, the traditional manual welding mode has significant drawbacks: the welding operation environment is poor, and the welder needs to be exposed to high temperature and welding fume environment for a long time; the strong light of electric arc (electric arc light contains a large amount of ultraviolet and infrared) will cause chronic damage to eyes and skin, and even cause photophthalmia; high frequency and high noise will damage the hearing system, in addition, metal oxides and harmful gases in welding fume are also easy to induce respiratory diseases, which seriously threatens the health of welders, so the development of automatic welding technology and welding robots is driven by the industry.

[0003] The existing welding robot products and researches mostly rely on fixed mechanical arms, which are usually rigidly fixed on the workbench or production line, and the working range is completely limited by the arm length, joint activity angle and installation position of the mechanical arm. This structural defect seriously restricts the versatility and working flexibility of the welding robot, and it is difficult to quickly respond to the dynamic changes of production demand. Moreover, as a high-power device, the power of the welding equipment can exceed 10000W, so it cannot use a battery and must use a high-capacity cable for power supply, which further limits the flexibility of the existing welding robot. SUMMARY

[0004] The main purpose of the present application is to provide a moving path planning method, device and equipment of a welding robot, which aims to solve the technical problems that the existing welding robot has poor versatility and insufficient working flexibility due to the influence of working range and cable, and it is difficult to quickly respond to the dynamic changes of production demand, resulting in low welding efficiency.

[0005] To achieve the above purpose, the present application provides a moving path planning method of a welding robot, which is applied to a welding robot, the welding robot comprises a welding module and a moving module, the welding robot is connected with a cable for power supply, and the moving path planning method of the welding robot comprises the following steps:

[0006] A cable model is constructed based on the position coordinates of key points on the cable connected with the welding robot, the key points include fixed end points, moving end points on the cable and at least one cable inflection point between the fixed end points and the moving end points, the cable model contains a two-dimensional coordinate array of each key point, and the moving end points are the current position coordinates of the welding robot;

[0007] constructing an open list and a closed list, taking a current position coordinate of the welding robot as a start node, and adding the start node and adjacent nodes of the start node to the open list, a cost parameter of the start node being configured as zero, each node in the open list and the closed list storing a cable model of a corresponding parent node of the node;

[0008] selecting a current node meeting a cost condition from the open list, the cost condition being generated based on the cable model and a cost function of a path planning algorithm;

[0009] updating the cable model based on the position coordinate of the current node;

[0010] adding the current node to the closed list, and adding adjacent nodes of the current node to the open list, and returning to perform the step of selecting a current node meeting a cost condition from the open list until the current node is a target node;

[0011] traversing each node in the closed list starting from the target node, and generating a movement path of the welding robot according to a parent-child relationship between each node.

[0012] Optionally, the updating the cable model based on the position coordinate of the current node comprises:

[0013] judging whether there is an obstacle between a first inflection point in the cable model and a movement end point at a current time based on the position coordinate of the current node, the first inflection point being a one-degree adjacent inflection point of a movement end point at a previous time;

[0014] if there is an obstacle between the first inflection point and the movement end point at the current time, performing point-by-point traversal from the first inflection point to the movement end point at the previous time, and monitoring whether there is an obstacle between each traversed point and the movement end point at the current time in the traversal process;

[0015] in response to there being no obstacle between the current traversed point and the movement end point at the current time, taking the current traversed point as a newly added cable inflection point, and replacing the movement end point at the previous time with the movement end point at the current time based on the position coordinate of the current node to update the cable model.

[0016] Optionally, after the judging whether there is an obstacle between the first inflection point in the cable model and the movement end point at the current time based on the position coordinate of the current node, the method further comprises:

[0017] if there is no obstacle between the first inflection point and the current moving endpoint, determining a triangular region composed of the current moving endpoint, the first inflection point and a second inflection point in the cable model, the second inflection point being a two-degree adjacent inflection point of the previous moving endpoint, and judging whether there is an obstacle in the triangular region;

[0018] in response to the triangular region having no obstacle, deleting the position coordinates of the first inflection point from the cable model to update the cable model;

[0019] in response to the triangular region having an obstacle, replacing the previous moving endpoint with the current moving endpoint based on the position coordinates of the current node to update the cable model.

[0020] Optionally, the filtering of the candidate node from the open list according to the cost condition comprises:

[0021] filtering a candidate node from the open list according to the cost condition;

[0022] updating the cable model based on the position coordinates of the candidate node, and determining a cable model length based on the updated cable model, the cable model length being calculated based on the following formula:

[0023]

[0024] wherein, L represents the total length of the cable model, N represents the number of key points in the cable model, Xi represents the horizontal coordinate of the i-th key point in the cable model, Yi represents the vertical coordinate of the i-th key point in the cable model;

[0025] judging whether the cable model length exceeds a cable length threshold value;

[0026] if the cable model length exceeds the cable length threshold value, adding the candidate node to a closed list, and returning to the step of filtering the candidate node from the open list according to the cost condition;

[0027] if the cable model length does not exceed the cable length threshold value, taking the candidate node as a current node, and continuing to perform the step of updating the cable model based on the position coordinates of the current node.

[0028] Optionally, before the filtering of the candidate node from the open list according to the cost condition, the method further comprises:

[0029] ​​The target cost function is constructed based on the cost function of the cable model and path planning algorithm stored at each node;

[0030] Cost conditions are generated based on the target cost function, and the cost conditions include selecting the node with the lowest cost parameter from the open list as the current node.

[0031] Optionally, the objective cost function includes:

[0032]

[0033] in, The node representing the output of the cost function The cost parameter, Represents a node Cable model corresponding to the parent node The number of key points in Represents the first in the cable model The x-coordinates of the key points Represents the first in the cable model The ordinates of the key points Indicates the cost weight of cable length. Represents the distance from the starting node to the node. The actual cost, Indicates from node The predicted cost to the target node.

[0034] Furthermore, to achieve the above objectives, the present invention also proposes a path planning device for a welding robot. The device is applied to a welding robot, which includes a welding module and a movement module. The welding robot is connected to a power supply cable. The path planning device for the welding robot includes:

[0035] The cable model construction module is used to construct a cable model based on the location coordinates of key points on the cable connected to the welding robot. The key points include a fixed end point, a moving end point, and at least one cable bend between the fixed end point and the moving end point. The cable model contains a two-dimensional coordinate array of each key point, and the moving end point is the current position coordinate of the welding robot.

[0036] The list construction module is used to construct open lists and closed lists. The current position coordinates of the welding robot are used as the starting node, and the starting node and its adjacent nodes are added to the open list. The cost parameter of the starting node is configured to be zero. Each node in the open list and the closed list stores the cable model of its corresponding parent node.

[0037] a node screening module configured to screen a current node meeting a cost condition from the open list, the cost condition being generated based on a cable model and a cost function of a path planning algorithm;

[0038] a model updating module configured to update the cable model based on a position coordinate of the current node;

[0039] a loop searching module configured to add the current node to the closed list, add a neighboring node of the current node to the open list, and return to perform the step of screening a current node meeting a cost condition from the open list until the current node is a target node;

[0040] a path planning module configured to traverse each node in the closed list starting from the target node, and generate a movement path of the welding robot according to a parent-child relationship between each node.

[0041] In addition, to achieve the above object, the present application further provides a welding robot movement path planning device, which comprises a memory, a processor and a welding robot movement path planning program stored in the memory, wherein the processor is configured to run the welding robot movement path planning program, and the computer program is configured to implement the steps of the welding robot movement path planning method as described above.

[0042] In addition, to achieve the above object, the present application further provides a computer readable storage medium, wherein the computer readable storage medium stores a computer program, and the computer program is executed by a processor to implement the steps of the welding robot movement path planning method as described above.

[0043] In addition, to achieve the above object, the present application further provides a computer program product, wherein the computer program product comprises a computer program, and the computer program is executed by a processor to implement the steps of the welding robot movement path planning method as described above.

[0044] The application is applied to a welding robot, the welding robot comprises a welding module and a moving module, and the welding robot is connected with a cable for power supply; the application constructs a cable model based on position coordinates of key points on the cable connected with the welding robot, the key points include fixed end points, moving end points and at least one cable inflection point between the fixed end points and the moving end points on the cable, the cable model contains a two-dimensional coordinate array of the key points, the moving end points are current position coordinates of the welding robot, an open list and a closed list are constructed, the current position coordinates of the welding robot are taken as a starting node, and the starting node and adjacent nodes of the starting node are added to the open list, a cost parameter of the starting node is configured as zero, each node in the open list and the closed list stores a cable model of a corresponding parent node, a current node meeting a cost condition is filtered out from the open list, the cost condition is generated based on the cable model and a cost function of a path planning algorithm, the cable model is updated based on position coordinates of the current node, the current node is added to the closed list, adjacent nodes of the current node are added to the open list, and the step of filtering out the current node meeting the cost condition from the open list is returned to be executed until the current node is a target node, each node in the closed list is traversed starting from the target node, and a moving path of the welding robot is generated according to parent-child relationships between the nodes; since the application constructs the cable model of the power supply cable connected with the welding robot, and updates the cable model based on position coordinates of the current node found in the node search process, the real motion state and distribution state of the cable of the welding robot are dynamically updated, the current node meeting the cost condition is searched through circulation, a path with shorter cable length is planned under the condition of meeting the cable limitation, the generality and flexibility of the welding robot are effectively improved, the problems of cable winding and length limitation are avoided, dynamic changes of production demands are quickly responded, and welding efficiency is greatly improved. BRIEF DESCRIPTION OF DRAWINGS

[0045] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced. Obviously, for those skilled in the art, other drawings can also be obtained without creative labor.

[0046] Figure 1 FIG. 1 is a structural schematic diagram of a moving path planning device of a welding robot related to a hardware running environment of an embodiment of the present application;

[0047] Figure 2 FIG. 2 is a flowchart of a moving path planning method of a welding robot of a first embodiment of the present application;

[0048] Figure 3 FIG. 3 is a construction schematic diagram of a cable model in an embodiment of a moving path planning method of a welding robot of the present application;

[0049] Figure 4(a) is a map of a real environment in an embodiment of the method for planning a movement path of a welding robot;

[0050] Figure 4(b) is a map after gridding in an embodiment of the method for planning a movement path of a welding robot;

[0051] Figure 5 Figure 5 is a flowchart of a path planning algorithm improved by taking cable length into account in an embodiment of the method for planning a movement path of a welding robot;

[0052] Figure 6 Figure 6 is a schematic diagram of a simulation demonstration environment in an embodiment of the method for planning a movement path of a welding robot;

[0053] Figure 7(a) is a schematic diagram of path planning with no restriction on cable length in an embodiment of the method for planning a movement path of a welding robot;

[0054] Figure 7(b) is a schematic diagram of path planning with restriction on cable length in an embodiment of the method for planning a movement path of a welding robot;

[0055] Figure 7(c) is a schematic diagram of path planning with restriction on cable length and selection of the path with the shortest cable length in an embodiment of the method for planning a movement path of a welding robot;

[0056] Figure 8 Figure 8 is a flowchart of a second embodiment of the method for planning a movement path of a welding robot;

[0057] Figure 9 Figure 9 is a flowchart of updating of a cable model in a second embodiment of the method for planning a movement path of a welding robot;

[0058] Figure 10(a) is a schematic diagram of judging whether there is an obstacle between a first inflection point and a movement end point at a current time;

[0059] Figure 10(b) is a schematic diagram of an obstacle between a first inflection point and a movement end point at a current time;

[0060] Figure 10(c) is a schematic diagram of point-by-point traversal from a first inflection point to a movement end point at a previous time;

[0061] Figure 10(d) is a schematic diagram of adding an inflection point and updating a cable model;

[0062] Figure 10(e) is a schematic diagram of judging whether there is an obstacle in a triangular region;

[0063] Figure 10(f) is a schematic diagram of an obstacle in a triangular region;

[0064] Fig. 10 (g) is a schematic diagram of a triangular region without an obstacle;

[0065] Figure 11 Fig. 1 is a structural block diagram of a mobile path planning device of a welding robot according to an embodiment of the present application.

[0066] The implementation, functional features and advantages of the present application will be further described with reference to the embodiments and the accompanying drawings. DETAILED DESCRIPTION

[0067] It should be understood that the specific embodiments described herein are merely exemplary and do not limit the present application.

[0068] Referring to Figure 1 , Figure 1 Fig. 2 is a structural schematic diagram of a mobile path planning device of a welding robot according to an embodiment of the present application.

[0069] As shown in Figure 1 , the mobile path planning device of the welding robot can include a processor 1001, such as a central processing unit (CPU), a communication bus 1002, a user interface 1003, a network interface 1004, and a memory 1005. The communication bus 1002 is used to realize the connection and communication between the components. The user interface 1003 can include a display, an input unit such as a keyboard, and can also include a standard wired interface, a wireless interface. The network interface 1004 can optionally include a standard wired interface, a wireless interface (such as a wireless fidelity (WI-FI) interface). The memory 1005 can be a high-speed random access memory (RAM), or a stable non-volatile memory (NVM), such as a disk memory. The memory 1005 can also be a storage device independent of the aforementioned processor 1001.

[0070] Those skilled in the art can understand that Figure 1 the structure shown in the foregoing embodiments does not constitute a limitation on the mobile path planning device of the welding robot, and can include more or fewer components than those shown, or combine certain components, or different component arrangements.

[0071] As shown in Figure 1 , the memory 1005, as a computer readable storage medium, can include an operating system, a network communication module, a user interface module, and a mobile path planning program of a welding robot.

[0072] InFigure 1 The network interface 1004 is mainly used for data communication with the network server, and the user interface 1003 is mainly used for data interaction with the user. The processor 1001 and the memory 1005 in the mobile path planning device of the welding robot can be arranged in the mobile path planning device of the welding robot. The mobile path planning device of the welding robot calls the mobile path planning program of the welding robot stored in the memory 1005 through the processor 1001, and executes the mobile path planning method of the welding robot provided in the embodiment of the application.

[0073] The embodiment of the application provides a mobile path planning method of a welding robot. Figure 2 Figure 2 FIG. 1 is a flowchart of a first embodiment of the mobile path planning method of the welding robot.

[0074] In the embodiment, the mobile path planning method of the welding robot is applied to the welding robot, the welding robot comprises a welding module and a moving module, the welding robot is connected with a cable for power supply, and the mobile path planning method of the welding robot comprises the following steps.

[0075] Step S10: Constructing a cable model based on the position coordinates of the key points on the cable connected with the welding robot.

[0076] It should be noted that the embodiment is applied to solve the limitation of the power supply cable of the welding machine on the path planning of the mobile welding robot, and combines the power supply cable constraint and the collision-free path planning of the mobile welding robot to accurately plan the moving path of the welding robot.

[0077] It should be understood that the execution subject of the embodiment can be a computing service device with data processing, network communication and program running functions, such as a tablet computer, a personal computer, a mobile phone and the like, or a terminal electronic device capable of realizing the above functions. The following takes the mobile path planning device (referred to as planning device) of the welding robot as an example to describe the embodiment and each of the following embodiments.

[0078] It should be noted that the welding robot can be a mobile welding robot, and the welding robot can be an unmanned motion platform carrying a welding module (such as a welding machine), a wire feeder, a mechanical arm, an industrial computer, a moving module (such as a moving chassis) and the like. The purpose is to realize automatic welding work. Since the welding module must be powered by a cable, the path planning of the welding robot must be restricted by the power supply cable of the welding machine.

[0079] ​It should be noted that the key points include fixed end points, moving end points on the cable and at least one cable inflection point between the fixed end points and the moving end points, the cable model contains a two-dimensional coordinate array of each key point, and the moving end point is the current position coordinate of the welding robot.

[0080] In some embodiments, establishing the cable model requires the following simplifications and assumptions for the moving welding robot and the cable:

[0081] (1) It is assumed that the welding robot is equipped with a cable winding and unwinding device, which can keep the cable in a tight state at all times.

[0082] (2) Since the cable is in a tight state, the planning device can reflect the actual state of the cable by simplifying the cable into a multi-segment line composed of a series of cable inflection points and line segments connecting the inflection points.

[0083] The process of establishing the cable model is shown in Figure 3 , Figure 3 is a schematic diagram of the construction of the cable model in an embodiment, Figure 3 shows the process of converting a real cable into a simplified cable and then converting the simplified cable into a cable model, and the finally established cable model stores the horizontal and vertical coordinates of all cable inflection points in the form of a two-dimensional array, wherein , represents the position coordinates of the fixed end point of the cable (usually a distribution box), and , represents the position coordinates of the moving end point of the cable (which is also the position of the welding robot). , to , are the horizontal and vertical coordinates of all inflection points from the fixed end point to the moving end point of the cable, i.e. the cable model is: .

[0084] Step S20: Constructing an open list and a closed list, taking the current position coordinate of the welding robot as a starting node, and adding the starting node and adjacent nodes of the starting node to the open list.

[0085] It should be noted that the present embodiment can obtain a grid map composed of grids by discretizing the actual environment, and the difference and connection between the grid map and the actual environment are shown in FIG. 4(a) and FIG. 4(b). FIG. 4(a) and FIG. 4(b) are schematic diagrams of gridding the actual environment in an embodiment, FIG. 4(a) is a map of the real environment, and FIG. 4(b) is a gridded map, with dark parts being obstacles and light parts being obstacle-free areas.

[0086] It should be noted that the starting node can be a grid unit where the current position coordinate of the welding robot is located, and the adjacent node can be a grid unit adjacent to the starting node, for example, the adjacent node can include the grid units adjacent to the starting node in the up, down, left, right, upper left, lower left, upper right and lower right directions.

[0087] In some embodiments, the planning device can obtain a grid map by rasterizing the current environment or the current area based on a preset grid unit size, construct an open list and a closed list, mark the current position coordinate of the welding robot as a starting node in the grid map, and add the starting node and adjacent nodes (i.e., one-degree adjacent grids of the grid unit where the starting node is located) of the starting node to the open list.

[0088] It should be noted that the open list is used to store nodes to be searched, and the closed list is used to store searched nodes.

[0089] It should be noted that the cost parameter of the starting node is configured as zero, and each node in the open list and the closed list stores a cable model of a corresponding parent node.

[0090] Step S30: filtering a current node meeting a cost condition from the open list.

[0091] It should be noted that the cost condition is generated based on the cable model and a cost function of a path planning algorithm. The path planning algorithm can be A search algorithm (i.e., A star algorithm).

[0092] In some embodiments, the planning device can calculate the cost parameters of the nodes in the open list by the cost function, sort the nodes based on the cost parameters, and filter a node with the lowest cost as the current node.

[0093] In some embodiments, the cost condition can be that the cost parameter of the node is the lowest in the open list, and the length of the cable model does not exceed a cable length threshold. If the cost of the node is the lowest, but the length of the cable model exceeds the cable length threshold, it is considered that the node is unreachable, and the node is moved from the open list to the closed list, and then the node with the lowest cost is selected from the open list.

[0094] Further, in order to accurately filter the optimal current node, ensure that the route does not exceed the cable length limit, and effectively shorten the path length, the above step S30 can include:

[0095] Step S301: filtering a candidate node meeting a cost condition from the open list.

[0096] It should be noted that a candidate node can be the node with the smallest cost parameter in the open list.

[0097] Step S302: Update the cable model based on the position coordinates of the candidate nodes, and determine the cable model length based on the updated cable model.

[0098] It should be noted that, since the candidate node at this moment stores the cable model of its parent node, the position coordinates of the candidate node are used as the new position of the moving end of the cable model to update the cable model of the parent node, resulting in a new cable model. Then, it is determined whether the length of the new cable model exceeds the limit. The length of the cable model is calculated based on the following formula:

[0099]

[0100] in, This indicates the total length of the cable model. This indicates the number of key points in the cable model. Represents the first in the cable model The x-coordinates of the key points Represents the first in the cable model The ordinates of the key points.

[0101] Step S303: Determine whether the length of the cable model exceeds the cable length threshold.

[0102] It should be noted that the cable length threshold can be the maximum active length of the power supply cable connected to the welding robot.

[0103] Step S304: If the cable model length exceeds the cable length threshold, add the candidate node to the closed list and return to the step of filtering candidate nodes that meet the cost conditions from the open list.

[0104] Understandably, if the length of the cable model exceeds the cable length threshold, the candidate node is considered to be unreachable from the target node. The candidate node is then moved from the open list to the closed list, and it is determined whether the candidate node is the target node. If it is, the pathfinding is completed; otherwise, the search continues for nodes that meet the cost conditions.

[0105] Step S305: If the length of the cable model does not exceed the cable length threshold, then the candidate node is taken as the current node, and the step of updating the cable model based on the position coordinates of the current node continues.

[0106] Understandably, if the length of the cable model does not exceed the limit, the neighboring nodes of the candidate node are searched and added to the open list, while the candidate node is added to the closed list as the current node, and the process continues to filter nodes from the open list.

[0107] Further, in order to prevent cable entanglement accidents, it is necessary to reduce the length of exposed cable. In an embodiment, the planning device can effectively reduce the length of cable occupied by the welding robot moving path by constructing an improved cost function based on the cable model and screening nodes based on the cost function. The step S30 can include the following steps before it:

[0108] Step S31: Construct a target cost function based on the cable model stored in each node and the cost function of the path planning algorithm.

[0109] It can be understood that, in order to prevent cable entanglement accidents, it is necessary to reduce the length of exposed cable. The algorithm is a heuristic search algorithm, and the cost function is crucial for guiding the search process. By improving the cost function, the path planning algorithm can be inclined to select a path with shorter cable length. In the search process, the algorithm will preferentially select the node with the smallest cost in the open list as the new current node. The cost function mainly consists of the following two parts:

[0110]

[0111] In the formula:

[0112] is a node to be calculated in the open list;

[0113] is the actual cost from the start node to node , which is usually the sum of the cost of reaching node from the start node along the path found. This method takes the sum of the Euclidean distance between all nodes on the path to node as ;

[0114] is the heuristic estimated cost from node to the target node. This method uses the three-dimensional Euclidean distance between node and the target node in the configuration space as . Since the upper and lower boundaries of the configuration space are connected, when the distance between node and the target node in the vertical direction exceeds half the thickness of the configuration space, “the thickness of the configuration space minus the distance between node and the target node in the vertical direction” should be used instead.

[0115] ​Step S32: Generate cost conditions based on the target cost function, wherein the cost conditions include selecting the node with the lowest cost parameter from the open list as the current node.

[0116] It should be understood that, in order to make the path planning algorithm tend to choose the path with a shorter cable length, this embodiment incorporates the real-time cable length as a cost into the cost function, and the improved cost function is as follows.

[0117]

[0118] In the formula:

[0119] The node representing the output of the cost function The cost parameter;

[0120] Represents a node Cable model corresponding to the parent node The number of key points in;

[0121] For nodes Updated cable model The Middle The x-coordinates of the key points are in meters. );

[0122] For nodes Updated cable model The Middle The ordinates of the key points are in meters. );

[0123] The weight is set to the cable length when it is used as a cost, and in some embodiments it is set to 2.

[0124] Using the improved cost function As A The heuristic function of the algorithm can make the improved A During the path planning process, the algorithm tends to find paths that require less cable length.

[0125] Step S40: Update the cable model based on the position coordinates of the current node.

[0126] Understandably, this is because the current node stores its parent node ( Cable model , using the current node ( The coordinates of ) are used as the new position of the moving end of the cable model. ), the cable model of the parent node is updated with the new position of the moving end of the cable model as the coordinates of the current node, and the new cable model is denoted as .

[0127] Step S50: the current node is added to the closed list, and the adjacent nodes of the current node are added to the open list, and the step of screening the current node meeting the cost condition from the open list is returned to be executed until the current node is the target node.

[0128] It can be understood that, because the power cable of the welding machine usually has a limited length, the movement of the welding robot can cause the length of the power cable to exceed the limit and an accident occurs, so it is necessary to use a real-time updated cable length limit path planning process. The traditional A algorithm obtains the optimal path to the terminal point by looping "adding the adjacent nodes of the current node to the open list" and "selecting a new current node from the nodes to be searched in the open list according to the cost", so the open list stores all the nodes to be searched and their coordinates, cost, and parent node. In order to embed the cable length limit into the path finding process of the A algorithm, each node needs to store the cable model corresponding to its parent node additionally. The embedding process is shown in Figure 5 Compared with the newly added steps of the traditional A algorithm, the detailed process of the improved path planning algorithm in this embodiment is as follows:

[0129] Step a1: constructing an open list and a closed list, adding the starting node to the open list, and setting the cost of the starting node to 0. Selecting the node with the minimum cost from the open list as a new current node, denoted as .

[0130] Step a2: because the current node stores the cable model of its parent node ( ), the cable model of the parent node is updated with the coordinates of the current node as the new position of the moving end of the cable model , and the new cable model is denoted as . . .

[0131] Step a3: judging whether the length of the new cable model ) exceeds the limit.

[0132] Step a4: if the length of the cable model ) exceeds the limit, it is considered that the current node is not reachable, the current node is moved from the open list to the closed list, and step a6 is jumped to. If the length of the cable model does not exceed the limit, the adjacent nodes of the current node are found.

[0133] Step a5: Calculate the cost of the adjacent node, and update the cable model The adjacent node (for which the current node is its parent node) is given. If the adjacent node does not exist in the open list or the closed list, the adjacent node is added to the open list, and the current node is moved from the open list to the closed list.

[0134] Step a6: Determine whether the current node is the target point of the path finding. If yes, the path finding is completed; if no, return to step a1 until the open list is empty (no feasible path) or the target point is reached.

[0135] Step S60: Traverse each node in the closed list starting from the target node, and generate the movement path of the welding robot according to the parent-child relationship between each node.

[0136] It should be noted that for the movement needs of the welding robot, the current main solutions are as follows:

[0137] (1) Ground rail type welding robot: This scheme installs the welding robot on a movable ground rail to obtain a larger working range. However, the ground rail welding robot is essentially still a fixed welding robot, and has problems such as poor versatility and large self-weight.

[0138] (2) Magnetic mobile welding robot: This scheme uses a magnetic base to attract the welding robot around the area to be welded, and moves by manually carrying the welding robot, welding machine, wire feeder, control cabinet, cable, and other equipment to the working area. This scheme is relatively flexible, but requires a large amount of manpower.

[0139] It can be understood that, in order to solve the limitation of the welding machine power cable on the path planning of the mobile welding robot, the present embodiment constructs a cable model that can be updated in real time. The cable model is used to simplify the cable into multiple segments of lines, and a series of coordinates of cable inflection points are used to describe the state of the cable.

[0140] In some embodiments, the planning device can update the cable model based on the obstacles in the geometric region of the cable by detecting the obstacles in the geometric region of the cable, realize real-time updating of the cable model, and simulate complex working conditions such as cable crossing and winding around obstacles.

[0141] It should be understood that the present embodiment also proposes a set of path planning strategy embedding the cable model that can be updated in real time. The path planning strategy uses the real-time cable length limit to find the path, and obtains the robot path under the condition that the cable length does not exceed the limit. At the same time, the real-time cable length is embedded in the cost function of the algorithm, so that the algorithm tends to choose the path that occupies shorter cable length.

[0142] ​To demonstrate the path planning algorithm for the welding robot that takes into account cable length limitations proposed in this embodiment, a method was designed as follows: Figure 6 The scenario shown is simulated and demonstrated. Figure 6 This is a schematic diagram of a simulated demonstration environment. The scene simulates the welding of small workpieces in a factory, with a scene size of 20m × 20m and no boundaries. The small workpieces to be welded are placed on four workbenches, each measuring 2m × 2m, with a spacing of 6m between them. The maximum length of the cable supplying power to the welding machine is 45m, and the power distribution box (fixed end) supplying power to the cable is located in the upper left corner of the scene. The cable winds clockwise around the lower left welding workbench and connects to the mobile welding robot located in the upper right corner, initially occupying a cable length of 38m. The collision box of the mobile welding robot measures 3.2m × 1.2m, initially located in the upper right corner of the scene, and ending in the lower right corner, a distance of 16m.

[0143] The results of the simulated path planning are shown in Figures 7(a), 7(b), and 7(c). Figures 7(a), 7(b), and 7(c) respectively demonstrate the path planning results and the cable state when the robot reaches the destination under three conditions: no constraints, only a cable length limit, and a cable length limit combined with choosing a path with a shorter cable length. As shown in Figure 7(a), the red solid line represents the path obtained without any constraints. This path causes the cable length to exceed the limit before reaching the destination, reaching a maximum of 51m. As shown in Figure 7(b), the green dashed line represents the path obtained under the condition that the cable length is only limited to the limit. This path bypasses the two welding workbenches on the right to reach the destination. The cable length used in this path does not exceed the limit, but the cable is still tangled. As shown in Figure 7(c), the blue dotted line represents the path obtained by the algorithm under the conditions of both limiting the cable length to the limit and choosing a path with a shorter cable length. This path bypasses the welding workbench located in the lower left corner counterclockwise before reaching the destination. The chosen path minimizes cable length and is the longest among the three methods. The path winds counter-clockwise around the workbench in the lower left corner of the scene and reaches the target location, demonstrating that this path planning method can still complete path planning even in complex conditions such as when the cable is tangled.

[0144] The embodiment is based on the key point position coordinates on the cable connected with the welding robot to construct a cable model, the key points include fixed end points, moving end points and at least one cable inflection point between the fixed end points and the moving end points on the cable, the cable model contains a two-dimensional coordinate array of each key point, the moving end point is the current position coordinate of the welding robot, an open list and a closed list are constructed, the current position coordinate of the welding robot is taken as a starting node, and the starting node and adjacent nodes of the starting node are added to the open list, the cost parameter of the starting node is configured as zero, each node in the open list and the closed list stores the cable model of the corresponding parent node, a current node meeting a cost condition is filtered out from the open list, the cost condition is generated based on the cable model and a cost function of a path planning algorithm, the cable model is updated based on the position coordinate of the current node, the current node is added to the closed list, adjacent nodes of the current node are added to the open list, and the step of filtering out the current node meeting the cost condition from the open list is returned to be executed until the current node is a target node, each node in the closed list is traversed starting from the target node, and a moving path of the welding robot is generated according to the parent-child relationship between the nodes; since the cable model of the power supply cable connected with the welding robot is constructed, and the cable model is updated based on the position coordinate of the current node found in the node search process, the real motion state and distribution state of the cable of the welding robot are dynamically updated, the current node meeting the cost condition is searched through circulation, the path with shorter cable length is planned under the condition of meeting the cable limitation, the generality and flexibility of the welding robot are effectively improved, the problems of cable winding and length limitation are avoided, the dynamic change of production demand is quickly responded, and the welding efficiency is greatly improved.

[0145] Reference Figure 8 , Figure 8 The flowchart of the second embodiment of the moving path planning method of the welding robot.

[0146] Based on the first embodiment, in the embodiment, the step S40 further includes:

[0147] Step S401: judging whether there is an obstacle between the first inflection point in the cable model and the moving end point at the current time based on the position coordinate of the current node.

[0148] It should be noted that the first inflection point is a first-adjacent inflection point of the moving end point at the last time. The first-adjacent inflection point is adjacent to the moving end point at the last time, and there is no other inflection point between them.

[0149] Step S4021: If there is an obstacle between the first inflection point and the mobile end point at the current time, then point-by-point traversal is performed from the first inflection point to the mobile end point at the time one step before the current time, and it is monitored whether there is an obstacle between each traversed point and the mobile end point at the current time during the traversal.

[0150] It should be noted that the point-by-point traversal from the first inflection point to the mobile end point at the time one step before the current time can be performed in grid units.

[0151] Step S4022: In response to the fact that there is no obstacle between the current traversed point and the mobile end point at the current time, the current traversed point is taken as a newly added cable inflection point, and the mobile end point at the time one step before the current time is replaced by the mobile end point at the current time based on the position coordinates of the current node, so as to update the cable model.

[0152] It can be understood that if there is an obstacle between the current traversed node and the current node, the node is continuously traversed.

[0153] Step S4121: If there is no obstacle between the first inflection point and the mobile end point at the current time, a triangular region composed of the mobile end point at the current time, the first inflection point and a second inflection point in the cable model is determined, and it is judged whether there is an obstacle in the triangular region.

[0154] It should be noted that the second inflection point is a two-degree adjacent inflection point of the mobile end point at the time one step before the current time. The two-degree adjacent inflection point is an adjacent inflection point which is separated from the mobile end point at the time one step before the current time by one inflection point.

[0155] Step S4122: In response to the fact that there is no obstacle in the triangular region, the position coordinates of the first inflection point are deleted from the cable model, so as to update the cable model.

[0156] Step S4123: In response to the fact that there is an obstacle in the triangular region, the mobile end point at the time one step before the current time is replaced by the mobile end point at the current time based on the position coordinates of the current node, so as to update the cable model.

[0157] It should be noted that as the cable end (mobile welding robot) moves between obstacles, the state of the cable will change, and its model also needs to be updated. In the process of path planning in the configuration space using the A algorithm, the cable model is updated once every time the node in the open list is selected as the current node. The updating process of the cable model is shown in Figure 9 and FIGS. 10(a) to 10(g), Figure 9Fig. 10(a) is a schematic diagram of judging whether there is an obstacle between the first inflection point and the moving end point at the current time, Fig. 10(b) is a schematic diagram of there being an obstacle between the first inflection point and the moving end point at the current time, Fig. 10(c) is a schematic diagram of point-by-point traversal from the first inflection point to the moving end point at the previous time, Fig. 10(d) is a schematic diagram of adding an inflection point and updating the cable model, Fig. 10(e) is a schematic diagram of judging whether there is an obstacle in the triangular region, Fig. 10(f) is a schematic diagram of there being an obstacle in the triangular region, and Fig. 10(g) is a schematic diagram of there being no obstacle in the triangular region. The detailed process is as follows:

[0158] Step c1: As shown in Fig. 10(a), when the updating process starts, the cable model at the previous time stores n cable inflection points, which are respectively. The position of the moving end of the cable at the current time is . The updating process first detects whether there is an obstacle between the line connecting the two points and . If there is an obstacle, go to step c2; if not, go to step c3.

[0159] Step c2: If there is an obstacle between the line connecting the two points and , as shown in Fig. 10(b), traverse point-by-point from the point to the point at a small interval. Assuming that the coordinates of the current point in the traversal are , detect whether there is an obstacle between the line connecting the two points and , as shown in Fig. 10(c). If there is an obstacle, continue to traverse; if not, consider the current as a newly added inflection point in the cable model. As shown in Fig. 10(d), update the model, insert the point between the point and the point , and replace with , to complete the updating of the cable model.

[0160] Step c3: If there is no obstacle between the line connecting the two points and , as shown in Fig. 10(e), it is necessary to judge whether there is an obstacle in the triangular region surrounded by the point , the point , and the point . If there is an obstacle in the triangular region, as shown in Fig. 10(f), replace , with ​, complete an update. If there is no obstacle in the triangular area, as shown in FIG. 10 (g), delete , complete an update.

[0161] With the movement of the cable end between the two groups of obstacles, the real-time change of the cable model. The embodiment can not only realize the real-time update of the cable model, but also simulate the complex working conditions such as cable crossing and winding obstacles.

[0162] The embodiment realizes real-time updating of the cable model based on the distribution of obstacles by judging whether there is an obstacle between the first inflection point in the cable model and the moving end point at the current time, thereby accurately dynamically simulating the real state of the cable, thereby providing accurate data support for path planning of the welding robot, and improving the accuracy of path planning.

[0163] In addition, the embodiment of the present application also provides a computer readable storage medium, the computer readable storage medium stores a moving path planning program of a welding robot, and the moving path planning program of the welding robot is executed by a processor to realize the steps of the moving path planning method of the welding robot as described above.

[0164] The computer readable storage medium provided by the present application may, for example, be a U disk, but is not limited to an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, system or device, or any combination of the above. More specific examples of computer readable storage media can include, but are not limited to, an electrical connection with one or more conductive wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In the present embodiment, the computer readable storage medium can be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, system or device. The program code contained on the computer readable storage medium can be transmitted by any suitable medium, including but not limited to electrical wires, optical cables, RF (Radio Frequency), etc., or any suitable combination of the above.

[0165] The above computer readable storage medium can be included in the moving path planning device of the welding robot; or it can exist separately and not be assembled into the moving path planning device of the welding robot.

[0166] Further, the present application also provides a computer program product comprising a mobile path planning program of a welding robot, wherein the mobile path planning program of the welding robot, when executed by a processor, implements the steps of the mobile path planning method of the welding robot as described above.

[0167] The computer program product of the present application has substantially the same implementation as the above-mentioned mobile path planning method of the welding robot, and thus will not be described here again.

[0168] Referring to Figure 11 , Figure 11 FIG. 1 is a structural block diagram of a first embodiment of a mobile path planning device of a welding robot according to the present application.

[0169] As shown in FIG. 1, the device according to the present embodiment is applied to a welding robot, wherein the welding robot comprises a welding module and a moving module, and the welding robot is connected with a cable for power supply, and the mobile path planning device of the welding robot according to the present embodiment comprises: Figure 11 a cable model construction module 10, configured to construct a cable model based on position coordinates of key points on the cable connected with the welding robot, wherein the key points comprise a fixed end point, a moving end point on the cable, and at least one cable inflection point between the fixed end point and the moving end point, and the cable model comprises a two-dimensional coordinate array of each key point, and the moving end point is a current position coordinate of the welding robot;

[0170] a list construction module 20, configured to construct an open list and a closed list, and add a current position coordinate of the welding robot as a start node to the open list, and add the start node and adjacent nodes of the start node to the open list, wherein a cost parameter of the start node is configured as zero, and each node in the open list and the closed list stores a cable model of a corresponding parent node;

[0171] a node screening module 30, configured to screen a current node meeting a cost condition from the open list, wherein the cost condition is generated based on a cable model and a cost function of a path planning algorithm;

[0172] a model updating module 40, configured to update the cable model based on a position coordinate of the current node;

[0173] a loop search module 50, configured to add the current node to the closed list, and add adjacent nodes of the current node to the open list, and return to execute the step of screening the current node meeting the cost condition from the open list until the current node is a target node;

[0174]

[0175] ​The path planning module 60 is configured to start from the target node to traverse each node in the closed list, and generate the movement path of the welding robot according to the parent-child relationship between each node.

[0176] The embodiment is based on the position coordinates of key points on the cable connected to the welding robot, the key points including fixed end points, a moving end point and at least one cable inflection point between the fixed end points and the moving end point, the cable model including a two-dimensional coordinate array of each key point, the moving end point being the current position coordinates of the welding robot, the open list and the closed list being constructed, the current position coordinates of the welding robot being taken as a starting node, the starting node and adjacent nodes of the starting node being added to the open list, the cost parameter of the starting node being configured as zero, each node in the open list and the closed list storing a cable model of a corresponding parent node, a current node meeting a cost condition being filtered out from the open list, the cost condition being generated based on the cable model and a cost function of a path planning algorithm, the cable model being updated based on the position coordinates of the current node, the current node being added to the closed list, adjacent nodes of the current node being added to the open list, and the step of filtering out the current node meeting the cost condition from the open list being returned until the current node is a target node, the movement path of the welding robot being generated according to the parent-child relationship between each node in the closed list starting from the target node. Since the cable model of the power supply cable connected to the welding robot is constructed, and the cable model is updated based on the position coordinates of the current node found in the node search process, the real movement state and distribution state of the cable of the welding robot are dynamically updated, the current node meeting the cost condition is searched in a loop, the path with a shorter cable length is planned under the condition of meeting the cable limitation, the generality and flexibility of the welding robot are effectively improved, the problems of cable winding and length limitation are avoided, the dynamic changes of production requirements are quickly responded, and the welding efficiency is greatly improved.

[0177] The welding robot movement path planning device provided by the application adopts the welding robot movement path planning method in the above embodiment, and can solve the technical problem of welding robot movement path planning. Compared with the prior art, the welding robot movement path planning device provided by the application has the same beneficial effects as the welding robot movement path planning method provided by the above embodiment, and other technical features in the welding robot movement path planning device are the same as the features disclosed in the above embodiment method, which will not be repeated here.

[0178] It should be understood that the above is only an example, and the technical solutions of the application are not limited in any way. In specific applications, those skilled in the art can set it up as needed, and the application does not limit it.

[0179] It should be noted that the above-described workflow is merely illustrative and does not limit the scope of protection of the present application. In actual applications, a person skilled in the art can select part or all of the above-described workflow to achieve the purpose of the embodiment according to actual needs, which is not limited herein.

[0180] In addition, technical details not described in detail in the present embodiment can be found in the movement path planning method of the welding robot provided by any embodiment of the present application, which will not be described here again.

[0181] It should be noted that in this document, the terms "comprise", "comprise", or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or system including a series of elements includes not only those elements, but also other elements not explicitly listed, or other elements inherent to such a process, method, article or system. Without more limitations, the element defined by the statement "comprises a" does not exclude the presence of additional identical elements in the process, method, article or system including the element.

[0182] The above-mentioned embodiment numbers of the present application are only for description, not representing the advantages and disadvantages of the embodiments.

[0183] From the above description of the embodiments, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be realized by means of software and necessary general hardware platform, of course, also can be realized by hardware, but in many cases, the former is a better embodiment. Based on such understanding, the technical solutions of the present application or the part that contributes to the prior art can be embodied in the form of software product, which is stored in a storage medium (such as read-only memory / random access memory, magnetic disk, optical disk), including a plurality of instructions to make a terminal device (which can be a mobile phone, computer, server, air conditioner, or network device, etc.) execute the method described in each embodiment of the present application.

[0184] The above is only the preferred embodiment of the present application, and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation, or direct or indirect application in other related technical fields, is also included in the patent protection scope of the present application.

Claims

1. A method for planning the movement path of a welding robot, characterized in that, The method is applied to a welding robot, which includes a welding module and a movement module. The welding robot is connected to a power supply cable, and the movement path planning method for the welding robot includes: A cable model is constructed based on the coordinates of key points on the cable connected to the welding robot. The key points include a fixed end point, a moving end point, and at least one cable bend between the fixed end point and the moving end point. The cable model contains a two-dimensional coordinate array of each key point, and the moving end point is the current position coordinate of the welding robot. An open list and a closed list are constructed. The current position coordinates of the welding robot are used as the starting node. The starting node and its adjacent nodes are added to the open list. The cost parameter of the starting node is configured to zero. Each node in the open list and the closed list stores the cable model of its corresponding parent node. The current node that meets the cost condition is selected from the open list. The cost condition is generated based on the cable model and the cost function of the path planning algorithm. Update the cable model based on the current node's position coordinates; Add the current node to the closed list, add the adjacent nodes of the current node to the open list, and return to the step of filtering the current node that meets the cost condition from the open list, until the current node is the target node; Starting from the target node, traverse each node in the closed list and generate the movement path of the welding robot based on the parent-child relationship between the nodes; The process of updating the cable model based on the current node's position coordinates includes: Based on the position coordinates of the current node, determine whether there is an obstacle between the first inflection point in the cable model and the moving endpoint at the current moment. The first inflection point is the first degree adjacent inflection point of the moving endpoint at the previous moment. If there is an obstacle between the first inflection point and the current moving endpoint, then the process is to traverse point by point from the first inflection point to the previous moving endpoint, and monitor whether there is an obstacle between each traversed point and the current moving endpoint during the traversal process. In response to the absence of obstacles between the currently traversed point and the current moving endpoint, the currently traversed point is taken as a new cable turning point, and the moving endpoint of the previous moment is replaced with the moving endpoint of the current moment based on the position coordinates of the current node, so as to update the cable model. If there is no obstacle between the first inflection point and the current moving endpoint, then the triangular region formed by the current moving endpoint, the first inflection point, and the second inflection point in the cable model is determined, and it is determined whether there is an obstacle in the triangular region. The second inflection point is the second-degree adjacent inflection point of the moving endpoint at the previous moment. In response to the absence of obstacles in the triangular region, the position coordinates of the first inflection point are deleted from the cable model to update the cable model; In response to the presence of an obstacle in the triangular region, the moving endpoint from the previous moment is replaced with the moving endpoint from the current moment based on the position coordinates of the current node to update the cable model; Before filtering out the current node that meets the cost condition from the open list, the process also includes: A target cost function is constructed based on the cost function of the path planning algorithm, wherein the target cost function includes: in, The node representing the output of the cost function The cost parameter, Represents a node Cable model corresponding to the parent node The number of key points in the text Represents the first in the cable model The x-coordinates of the key points Represents the first in the cable model The ordinates of the key points Indicates the cost weight of cable length. Represents the distance from the starting node to the node. The actual cost, Indicates from node The predicted cost to the target node.

2. The method for planning the movement path of a welding robot as described in claim 1, characterized in that, The step of filtering the current node that meets the cost condition from the open list includes: Candidate nodes that meet the cost criteria are selected from the open list; The cable model is updated based on the position coordinates of the candidate nodes, and the cable model length is determined based on the updated cable model. The cable model length is calculated using the following formula: in, This indicates the total length of the cable model. This indicates the number of key points in the cable model. Represents the first in the cable model The x-coordinates of the key points Represents the first in the cable model The ordinates of the key points; Determine whether the length of the cable model exceeds the cable length threshold; If the cable model length exceeds the cable length threshold, the candidate node is added to the closed list, and the process returns to the step of filtering candidate nodes that meet the cost conditions from the open list. If the length of the cable model does not exceed the cable length threshold, the candidate node is taken as the current node, and the step of updating the cable model based on the position coordinates of the current node continues.

3. The method for planning the movement path of a welding robot as described in claim 1, characterized in that, Before filtering candidate nodes that meet the cost criteria from the open list, the process also includes: The target cost function is constructed based on the cost function of the cable model and path planning algorithm stored at each node; Cost conditions are generated based on the target cost function, and the cost conditions include selecting the node with the lowest cost parameter from the open list as the current node.

4. A path planning device for a welding robot, characterized in that, The device is configured to implement the motion path planning method for a welding robot as described in any one of claims 1 to 3. The device is applied to a welding robot, which includes a welding module and a movement module. The welding robot is connected to a power supply cable. The motion path planning device for the welding robot includes: The cable model construction module is used to construct a cable model based on the location coordinates of key points on the cable connected to the welding robot. The key points include a fixed end point, a moving end point, and at least one cable bend between the fixed end point and the moving end point. The cable model contains a two-dimensional coordinate array of each key point, and the moving end point is the current position coordinate of the welding robot. The list construction module is used to construct open lists and closed lists. The current position coordinates of the welding robot are used as the starting node, and the starting node and its adjacent nodes are added to the open list. The cost parameter of the starting node is configured to be zero. Each node in the open list and the closed list stores the cable model of its corresponding parent node. The node filtering module is used to filter out current nodes that meet the cost conditions from the open list. The cost conditions are generated based on the cable model and the cost function of the path planning algorithm. The model update module is used to update the cable model based on the position coordinates of the current node; The loop search module is used to add the current node to the closed list, add the adjacent nodes of the current node to the open list, and return to perform the step of filtering the current node that meets the cost condition from the open list until the current node is the target node; The path planning module is used to traverse each node in the closed list starting from the target node and generate the movement path of the welding robot according to the parent-child relationship between the nodes.

5. A path planning device for a welding robot, characterized in that, The welding robot's path planning device includes: a processor, a memory, and a welding robot path planning program stored in the memory. The processor is used to run the welding robot path planning program, which is configured to implement the welding robot path planning method as described in any one of claims 1 to 3.

6. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a path planning program for a welding robot, which, when executed by a processor, implements the path planning method for a welding robot as described in any one of claims 1 to 3.

7. A computer program product, characterized in that, The computer program product includes a path planning program for a welding robot, which, when executed by a processor, implements the steps of the path planning method for a welding robot as described in any one of claims 1 to 3.

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