UWB path planning navigation method and system for construction vehicle

Abstract

The invention discloses a UWB path planning navigation method for a construction vehicle, and the method comprises the following steps: S1, fixing the speed of the construction vehicle, and constructing a construction site road network in combination with a UWB base station, the speed of the construction vehicle and a GIS electronic map; s2, feeding back the condition of the construction vehicle by a UWB label, and dynamically defining a plurality of construction vehicle task starting points and closed nodes in a construction site road network according to the position data of the construction vehicle and the task state of the construction vehicle; s3, searching an optimal path of the construction vehicle by combining a plurality of construction vehicle task starting points and construction vehicle task end point coordinates; the method has the advantages that road resources can be utilized more effectively when multiple scheduling tasks are carried out, and the risk of road congestion is avoided; according to the method, the distance cost is considered, and meanwhile, the influence of the construction vehicles on the construction site in the steering process is considered, so that tasks are allocated to the proper construction vehicles, and paths are planned.

Description

Technical Field

[0001] The present invention relates to UWB path planning technology, in particular to a UWB path planning navigation method and system for construction vehicles. Background Art

[0002] In large-scale construction scenes, a large number of construction vehicles are usually required to work together. Due to the imperfect infrastructure, the GPS satellite positioning system has not recorded the scene map of the current construction vehicle scene, and the development cost of the GPS satellite positioning system is high. Vehicle drivers can only obtain construction vehicle tasks through handheld terminals, and the construction vehicle site roads lack effective signs, which may cause the following problems.

[0003] The assignment of construction vehicle tasks is not accurately and quickly assigned to the nearest unassigned driver, resulting in a slow scheduling process and poor scheduling efficiency; drivers lack effective navigation methods and cannot accurately find their destinations; and it is inconvenient to pass each other in the construction site. When multiple vehicles are performing tasks, they cannot effectively observe the driving trajectories of other vehicles, which easily leads to traffic jams. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art; to this end, the present invention proposes a UWB path planning and navigation method and system for construction vehicles, which are used to solve the technical problems of the prior art in which construction vehicle tasks are unreasonable and cannot be effectively scheduled.

[0005] To achieve the above object, the present invention provides a UWB path planning and navigation method for a construction vehicle, comprising the following steps:

[0006] S1, fix the speed of construction vehicles, and build the construction site road network by combining UWB base station, construction vehicle speed and GIS electronic map;

[0007] S2, the UWB tag feedbacks the construction vehicle status, and dynamically defines several construction vehicle task starting points and closed nodes in the construction site road network according to the construction vehicle location data and construction vehicle task status;

[0008] S3. Searching for the best path for the construction vehicle by combining the coordinates of the starting points and the end points of the construction vehicle tasks.

[0009] Further: The specific method of S1 is as follows:

[0010] Set the speed of the construction vehicle to a constant value V;

[0011] Import the 3D model of the construction vehicle site in the database, retain only the road part of the 3D model and convert the road part into a 2D planar model;

[0012] Each intersection of the two-dimensional planar road is defined as a node, directly connected intersections are set as adjacent nodes, and adjacent nodes are connected to construct a construction site road network, and the coordinates of the UWB base station are added to the construction site road network;

[0013] According to the constant value V of the construction vehicle speed, the generation time parameter t is added to the connection between adjacent nodes;

[0014] In order to ensure the accuracy and timeliness of dispatching navigation and avoid path overlap in multiple construction vehicle dispatching tasks, it is necessary to formulate a standard speed V for construction vehicles, thereby obtaining the time t that the construction vehicles spend on each road section (the path between two intersections). This will be used for subsequent cost evaluation of construction vehicle dispatching and for reflecting the usage of each road section at a fixed time point, avoiding repeated search and selection of the same road section in multiple dispatching tasks.

[0015] Further: the method for two-dimensionally planarizing the road portion is as follows:

[0016] Get the spatial coordinates of each intersection, directly calculate the distance between each coordinate point using the Euclidean distance formula, and calibrate the node represented by each intersection according to the actual distance represented by the calculation result;

[0017] The distance S between adjacent nodes is calculated according to the scale of the three-dimensional model, and the time parameter t required for the construction vehicle to move between adjacent nodes is directly solved based on the distance S and the constant speed V of the construction vehicle.

[0018] Further: The specific method of S2 is as follows:

[0019] The UWB tag transmits the construction vehicle status, including the construction vehicle location data and the construction vehicle mission status;

[0020] The construction vehicle location data is embedded into the construction site road network layer to generate each construction vehicle positioning point, and the construction vehicle positioning points are marked red or green according to the construction vehicle task status. When the task status is not empty, it is green, and when the task status is empty, it is red;

[0021] The green construction vehicle positioning points are marked as the starting points of the construction vehicle mission;

[0022] The two nearest adjacent nodes of the construction vehicle positioning point in red are defined as closed nodes, and the construction site road network disconnects the connection between the two closed nodes;

[0023] This step is used to select a construction vehicle that meets the scheduling conditions as an endpoint for subsequent path planning, and record the road section where the construction vehicles that do not meet the scheduling conditions are located as a closed section to avoid repeated selection during the path planning process and cause road congestion.

[0024] Further: The specific method of S3 is as follows:

[0025] Obtain the destination coordinates of the construction vehicle task and the start time of the construction vehicle task, and perform the following search tasks for each construction vehicle task in turn using the A* search algorithm according to the following rules:

[0026] Searching for the path that is closest to the end point of a construction vehicle task and the starting points of several construction vehicle tasks;

[0027] Searching for the path with the least number of nodes between the end point of a construction vehicle task and the starting points of several construction vehicle tasks;

[0028] Among them, when the search task appears that the angle formed by the direction vectors formed by a node and two adjacent nodes is greater than 90°, the next node of the node is reselected;

[0029] According to the construction vehicle scheduling cost function, the task with the lowest construction vehicle cost among the two search tasks is selected as the optimal path for the construction vehicle. The construction vehicle scheduling cost function is specifically as follows:

[0030]

[0031] Among them, k is the distance cost coefficient;

[0032] η is the time evaluation coefficient for construction vehicle tasks;

[0033] m is the total number of nodes in the search task, i∈m;

[0034] (t i , t i-1 ) is the time parameter from the i-1 node to the i-th node;

[0035] (d i ， d i-1 ) is the actual distance from the i-1 node to the i-th node;

[0036] h i is the steering processing coefficient at node i, which is determined by the direction of the construction vehicle entering and leaving node i, that is, the angle θ between the direction vector composed of node i-1 and node i and the direction vector composed of node i and node i+1; when θ≤45°, h i=0.1;60°≥θ>45°, h i = 0.3;

[0037] 90°≥θ>60°, h i = 0.6;| When θ>90°, it is not recommended to select the i+1th node and reselect;

[0038] This step is used to evaluate the cost of scheduling, which is specifically evaluated by distance, time and the number of nodes (intersections). Since the node represents the turning of the construction vehicle, the turning difficulty (influencing factor) of the construction vehicle is determined by the turning angle.

[0039] Further: Each construction vehicle task is processed by the following method:

[0040] The tasks are processed in sequence according to the start time of the construction vehicle task, that is, the time when the end point of the construction vehicle task sends a scheduling request. After the optimal path of the construction vehicle corresponding to the first construction vehicle task is selected, the connection between all nodes is adjusted and re-assigned according to the time parameter t between the departure time of the construction vehicle at the starting point of this construction vehicle task and all nodes on the optimal path of the construction vehicle. Specifically:

[0041] Based on the departure time, the fixed time period between each node and the next node is determined by directly accumulating the time parameter t between each node. The connection between the two adjacent nodes is disconnected according to this time period, that is, the connection between the two adjacent nodes in this time period does not support A* search;

[0042] The purpose of re-assigning the connections between all nodes in this step is to avoid the situation when multiple scheduling tasks are performed, in which the nodes used in the path planning corresponding to each scheduling task overlap with the nodes used in the path planning corresponding to the previous scheduling task in terms of the use of adjacent nodes (i.e., road sections) and usage time.

[0043] The present invention also provides a UWB path planning navigation system for construction vehicles, comprising: a plurality of UWB base stations, a terminal device;

[0044] The UWB base station wirelessly communicates with a UWB tag installed on a central control unit of a construction vehicle;

[0045] The UWB base station also wirelessly communicates with a terminal device.

[0046] Furthermore: the terminal device further includes: a memory and a processor;

[0047] The memory stores the method and steps for implementing the above-mentioned method;

[0048] The processor executes and implements the above methods and steps.

[0049] The beneficial effects of the present invention are as follows: a construction site road network established by the speed of construction vehicles and the actual distance allocates the time required for construction vehicles to move in each road section in the road network, which is convenient for more efficient use of road resources when multiple scheduling tasks are carried out and avoids the risk of road congestion; different from traditional methods, the present invention not only considers the distance cost but also takes into account the impact of the construction vehicles on the construction site during the turning process to allocate tasks to appropriate construction vehicles and plan routes. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] In order to more clearly illustrate the embodiments of the present invention and the technical solutions in the prior art, the drawings required for use in the embodiments and the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some implementation methods recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0051] Figure 1 It is a schematic diagram of the method flow of the present invention;

[0052] Figure 2 It is a schematic diagram of the system structure of the present invention. DETAILED DESCRIPTION

[0053] In order to make the purpose, technical scheme and advantages of the present invention more clearly understood, the present invention is described and illustrated below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. Based on the embodiments provided by the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the present invention.

[0054] Obviously, the drawings described below are only some examples or embodiments of the present invention. For ordinary technicians in this field, the present invention can be applied to other similar scenarios based on these drawings without any creative work.

[0055] In addition, it can be understood that although the efforts made in this development process may be complex and lengthy, for ordinary technicians in the field related to the contents disclosed in the present invention, some design, manufacturing or production changes based on the technical contents disclosed in the present invention are just conventional technical means and should not be understood as the contents disclosed in the present invention are insufficient.

[0056] If not otherwise specified, all embodiments and optional embodiments of the present invention can be combined with each other to form a new technical solution.

[0057] See also Figure 1, the method flow diagram of the present invention comprises the following steps:

[0058] S1, fix the speed of construction vehicles, and build the construction site road network by combining UWB base station, construction vehicle speed and GIS electronic map;

[0059] S2, the UWB tag feedbacks the construction vehicle status, and dynamically defines several construction vehicle task starting points and closed nodes in the construction site road network according to the construction vehicle location data and construction vehicle task status;

[0060] S3. Searching for the best path for the construction vehicle by combining the coordinates of the starting points and the end points of the construction vehicle tasks.

[0061] Specifically:

[0062] In order to ensure that the road network of the construction site is in line with reality, to ensure the accuracy and timeliness of the dispatching navigation, and to avoid the overlap of paths in the dispatching tasks of multiple construction vehicles, it is necessary to formulate a standard speed V for the construction vehicles to travel, thereby obtaining the time t that the construction vehicles spend on each road section (the path between two intersections), which is used for the subsequent cost evaluation of the construction vehicle dispatching and to reflect the usage of each road section at a fixed time point, so as to avoid repeated search and selection of the same road section in multiple dispatching tasks; for this, the speed of the construction vehicle is set to a fixed value V; the three-dimensional model of the construction vehicle site in the database is imported, and only the road part of the three-dimensional model is retained and the road part is two-dimensionally flattened; the two-dimensional planarization method of the road part is: obtain each intersection The spatial coordinates of the vehicle are directly calculated using the Euclidean distance formula to calculate the distance between each coordinate point. The node represented by each intersection is calibrated according to the real distance represented by the calculation result. Each intersection of the two-dimensional planar road is defined as a node. Directly connected intersections are set as adjacent nodes. Adjacent nodes are connected to construct a construction site road network. The coordinates of the UWB base station are added to the construction site road network to facilitate the positioning of each UWB tag (construction vehicle) received by the UWB base station through direct measurement of its own coordinates. The generation time parameter t is added to the connection between adjacent nodes according to the construction vehicle speed constant V. The distance S between adjacent nodes is specifically calculated by the three-dimensional model scale, and the solution is directly obtained based on the distance S and the construction vehicle speed constant V.

[0063] In order to determine the construction vehicles that can execute the scheduling task, a task reporting function is added to the UWB tag sending function to report whether the task status of the construction vehicle is empty or not, and the adjacent nodes corresponding to the construction vehicle in the area where the construction vehicle is located on the construction site road network are defined as closed nodes according to the task status sent by the construction vehicle, and the connection (road section) between the closed nodes does not participate in the path planning. The specific method is as follows: the UWB tag sends the construction vehicle status, including the construction vehicle location data and the construction vehicle task status; the construction vehicle location data is embedded in the construction site road network layer to generate each construction vehicle positioning point, and the construction vehicle positioning point is marked red and green according to the construction vehicle task status, green when the task status is not empty, and red when the task status is empty; the construction vehicle positioning points that are green are all marked as the starting points of the construction vehicle task; the two nearest adjacent nodes of the construction vehicle positioning point that is red are defined as closed nodes, and the construction site road network disconnects the connection between the two closed nodes, thereby determining the construction vehicles that can execute the task and the drivable road sections.

[0064] To ensure efficient dispatching of construction vehicles, there are usually two dispatching schemes (path planning schemes): 1. The traditional dispatching scheme that considers the shortest distance between the two; 2. The traditional dispatching scheme that considers the least number of nodes between the two;

[0065] However, due to the complex road conditions at the construction site, the shortest distance does not mean the best scheduling. The factors affecting scheduling, such as the number of nodes (intersections) that the construction vehicles pass through during the scheduling process and the difficulty of turning at each node, must also be considered.

[0066] Fewer intersections means fewer nodes passed through during the scheduling process, which means that this scheduling task occupies fewer nodes and sections. When there are other scheduling tasks, more nodes can be provided for other tasks to choose from.

[0067] A low steering difficulty means that the construction vehicle spends less time in the steering process and is less likely to cause congestion at the intersection. The steering difficulty is directly determined by its steering angle. When the steering angle of the construction vehicle does not exceed 45°, the steering difficulty is low. When the steering angle is greater than 45° to 60°, the steering difficulty increases slightly due to the length and width of the construction vehicle. At 60° to 90°, the steering process already takes a lot of time. By fitting the data at various angles, the corresponding relationship of the steering difficulty of the construction vehicle is: | When θ≤45°, h i = 0.1;

[0068] 60°≥θ>45°, h i=0.3;90°≥θ>60°, h i = 0.6;

[0069] However, passing through the least number of nodes does not mean optimal scheduling. The scheduling process is still limited by distance cost and time cost. Considering the scheduling cost, the scheduling method is as follows: obtain the coordinates of the end point of the construction vehicle task and the start time of the construction vehicle task, and perform the following search tasks for each construction vehicle task in turn using the A* search algorithm according to the following rules: search for the path with the shortest distance between the end point of the construction vehicle task and the starting points of several construction vehicle tasks; search for the path with the least nodes between the end point of the construction vehicle task and the starting points of several construction vehicle tasks; among them, when the angle formed by the direction vectors formed by a node and two adjacent nodes in the search task is greater than 90°, its turning difficulty is relatively large and is not considered, and the next node of the node is reselected; according to the construction vehicle scheduling cost function, the task with the lowest construction vehicle cost in the two search tasks is selected as the optimal path for the construction vehicle. The construction vehicle scheduling cost function is specifically as follows:

[0070]

[0071] Among them, k is the distance cost coefficient;

[0072] η is the time evaluation coefficient for construction vehicle tasks;

[0073] m is the total number of nodes in the search task, i∈m;

[0074] (t i , t i-1 ) is the time parameter from the i-1 node to the i-th node;

[0075] (d i ， d i-1 ) is the actual distance from the i-1 node to the i-th node;

[0076] h i is the steering processing coefficient at node i, which is determined by the direction of the construction vehicle entering and leaving node i, that is, the angle θ between the direction vector composed of node i-1 and node i and the direction vector composed of node i and node i+1; when θ≤45°, h i=0.1;60°≥θ>45°, h i = 0.3;

[0077] 90°≥θ>60°, h i = 0.6; | When θ>90°, it is not recommended to take the i+1th node and reselect.

[0078] In order to avoid the situation that the corresponding multiple path planning overlaps in the use of road sections and use time when multiple scheduling tasks are carried out simultaneously, the scheduling task of each construction vehicle also includes: processing in sequence according to the start time of the construction vehicle task (i.e., the time when the end point of the construction vehicle task sends a scheduling request), when the optimal path of the construction vehicle corresponding to the first construction vehicle task is selected, the connection between all nodes is adjusted and re-assigned according to the departure time of the construction vehicle at the starting point of this construction vehicle task and the time parameter t between all nodes on the optimal path of the construction vehicle. Specifically, based on the departure time, the fixed time period between the construction vehicle executing the task driving to each node and the next node is determined by directly accumulating the time parameter t between each node, and the connection between the two adjacent nodes is disconnected according to this time period, that is, the connection between the two adjacent nodes in this time period does not support A* search; the planning of any subsequent scheduling tasks adopts this operation, and by comparing the road section and use time used in the current scheduling task with the road section and use time used in the previous scheduling task, the planned path can be reselected to avoid the road congestion problem caused by repeated selection of sections in the same time period.

[0079] See also Figure 2 , is a schematic diagram of the system structure of the present invention;

[0080] Among them, it includes a UWB base station and a terminal device. The UWB base station is set according to the size, structure and coverage of the construction site; the terminal device is usually a PC computer device with storage and processing capabilities; the number of UWB tags corresponds to the number of construction vehicles on the site, ensuring that there is at least one for each construction vehicle; subsequently, the UWB tags can be classified according to the type of construction vehicles, so that the corresponding scheduling tasks can accurately find the required construction vehicles.

[0081] The above is a very detailed description of one or more embodiments of the present invention, but the content is only a specific example of the present invention and cannot be considered to limit the scope of application of the present invention. Any other methods and changes proposed based on the content of the present invention should fall within the scope of patent protection of the present invention.

Claims

1. A UWB path planning and navigation method for construction vehicles, characterized in that: The steps include: S1, fix the speed of construction vehicles, and build the construction site road network by combining UWB base station, construction vehicle speed and GIS electronic map; S2, the UWB tag feedbacks the construction vehicle status, and dynamically defines several construction vehicle task starting points and closed nodes in the construction site road network according to the construction vehicle location data and construction vehicle task status; S3. Searching for the best path for the construction vehicle by combining the coordinates of the starting points and the end points of the construction vehicle tasks.

2. A UWB path planning and navigation method for construction vehicles according to claim 1, characterized in that: The specific method of S1 is as follows: Set the speed of the construction vehicle to a constant value V; Import the 3D model of the construction vehicle site in the database, retain only the road part of the 3D model and convert the road part into a 2D planar model; Each intersection of the two-dimensional planar road is defined as a node, directly connected intersections are set as adjacent nodes, and adjacent nodes are connected to construct a construction site road network, and the coordinates of the UWB base station are added to the construction site road network; According to the constant value V of the construction vehicle speed, a generation time parameter t is added to the lines between adjacent nodes.

3. A UWB path planning and navigation method for construction vehicles according to claim 2, characterized in that: The method for two-dimensional planarization of the road portion is as follows: Get the spatial coordinates of each intersection, directly calculate the distance between each coordinate point using the Euclidean distance formula, and calibrate the node represented by each intersection according to the actual distance represented by the calculation result; The distance S between adjacent nodes is calculated according to the scale of the three-dimensional model, and the time parameter t required for the construction vehicle to move between adjacent nodes is directly solved based on the distance S and the constant speed V of the construction vehicle.

4. A UWB path planning and navigation method for construction vehicles according to claim 1, characterized in that: The specific method of S2 is as follows: The UWB tag transmits the construction vehicle status, including the construction vehicle location data and the construction vehicle mission status; The construction vehicle location data is embedded into the construction site road network layer to generate each construction vehicle positioning point, and the construction vehicle positioning points are marked red or green according to the construction vehicle task status. When the task status is not empty, it is green, and when the task status is empty, it is red; The green construction vehicle positioning points are marked as the starting points of the construction vehicle mission; The two nearest adjacent nodes of the construction vehicle positioning point in red are defined as closed nodes, and the construction site road network disconnects the connection between the two closed nodes.

5. A UWB path planning and navigation method for construction vehicles according to claim 1, characterized in that: The specific method of S3 is as follows: Obtain the destination coordinates of the construction vehicle task and the start time of the construction vehicle task, and perform the following search tasks for each construction vehicle task in turn using the A* search algorithm according to the following rules: Searching for the path that is closest to the end point of a construction vehicle task and the starting points of several construction vehicle tasks; Searching for the path with the least number of nodes between the end point of a construction vehicle task and the starting points of several construction vehicle tasks; Among them, when the search task appears that the angle formed by the direction vectors formed by a node and two adjacent nodes is greater than 90°, the next node of the node is reselected; According to the construction vehicle scheduling cost function, the task with the lowest construction vehicle cost among the two search tasks is selected as the optimal path for the construction vehicle. The construction vehicle scheduling cost function is specifically as follows: Among them, k is the distance cost coefficient; η is the time evaluation coefficient for construction vehicle tasks; m is the total number of nodes in the search task, i∈m; (t i , t i-1 ) is the time parameter from the i-1 node to the i-th node; (d i ， d i-1 ) is the actual distance from the i-1 node to the i-th node; h i is the steering processing coefficient at node i, which is determined by the direction of the construction vehicle entering and leaving node i, that is, the angle θ between the direction vector composed of node i-1 and node i and the direction vector composed of node i and node i+1; when θ≤45°, h i=0.1;60°≥θ>45°, h i = 0.3; 90°≥θ>60°, h i = 0.6; | When θ>90°, it is not recommended to take the i+1th node and reselect.

6. A UWB path planning and navigation method for construction vehicles according to claim 5, characterized in that: Each construction vehicle task is handled by the following method: The tasks are processed in sequence according to the start time of the construction vehicle task, that is, the time when the end point of the construction vehicle task sends a scheduling request. After the optimal path of the construction vehicle corresponding to the first construction vehicle task is selected, the connection between all nodes is adjusted and re-assigned according to the time parameter t between the departure time of the construction vehicle at the starting point of this construction vehicle task and all nodes on the optimal path of the construction vehicle. Specifically: Based on the departure time, the fixed time period between each node and the next node is determined by directly accumulating the time parameter t between each node. The connection between the two adjacent nodes is disconnected according to this time period, that is, the connection between the two adjacent nodes in this time period does not support A* search.

7. A UWB path planning and navigation system for construction vehicles, characterized in that: include: Several UWB base stations and a terminal device; The UWB base station wirelessly communicates with a UWB tag installed on a central control unit of a construction vehicle; The UWB base station also wirelessly communicates with a terminal device.

8. A UWB path planning and navigation system for construction vehicles according to claim 7, characterized in that: The terminal device further includes: a memory and a processor; The memory stores the method and steps for implementing any one of claims 1 to 6; The processor executes the method and steps according to any one of claims 1 to 6.

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