CN111174797B - Closed area global path planning method - Google Patents

Abstract

The invention discloses a global path planning method for a closed area, which comprises the following steps: step S1, obtaining an environment map model of a closed area and generating an intermediate connection path; s2, acquiring a starting point and a target point for completing the job task; s3, performing corresponding global path planning according to the area where the starting point and the target point are located; s4, controlling the vehicle to run according to the planned global path; the environment map of the closed area in step S1 may be obtained by a dispatcher giving the area map, or by obtaining from related map software, dividing the large closed area map into two parts, and changing time by space, generating an intermediate connection road in the intermediate connection area for storage and standby, which is convenient for subsequent planning and rapid acquisition. According to the closed region global path planning method, the path planning in the closed region can be effectively and quickly realized through the setting from the step S1 to the step S4.

Description

A Global Path Planning Method for Enclosed Areas

technical field

The invention relates to the field of vehicle path planning, in particular to a global path planning method oriented to a closed area.

Background technique

The global path planning of unmanned vehicles refers to planning an effective path that is collision-free and can safely reach the target point based on a certain environment model, given the starting point and target point of the unmanned vehicle. The performance index may be the shortest route travel distance, the shortest movement time, and the like. After the vehicle obtains the global path, the unmanned vehicle system will control the vehicle to drive according to the planned path, and complete the specified task safely and efficiently.

For large enclosed areas such as ports, parks, mining areas, and farmland, the sub-areas that complete different tasks are distributed in different locations in the enclosed area, and the operation vehicles travel within the same sub-area or between different sub-areas to complete the operation tasks. The main existing global path planning methods for unmanned vehicles are as follows: Patent document CN 109085825 A proposes an optimal path selection method for unmanned mine cart mining. The radar sensor detects the surrounding environment and performs weight judgment on obstacle avoidance and target following, adjusts the driving direction according to the strength of the strengthened signal, avoids obstacles and drives to the target. Document CN102854880A proposes a robot global path planning method for uncertain environments in mixed terrain areas. The method first detects and builds a robot working environment model, including motion starting points and target points, static obstacle positions and shapes, and uncertain obstacles. The possible coverage area, terrain type and area covered, the optimal path is planned using the weighted traversable length of the path containing the terrain information and the path tolerance to avoid the uncertain obstacles in the area as the objective function. The task is completed with the lowest risk degree in the terrain environment; the patent document CN 107436603A proposes a method and system for automatic driving on a curved path of an agricultural vehicle. The method obtains the vehicle position information in real time and judges the angular deviation from the preset curved operating trajectory, and through the enhanced signal feedback Carrying out machine learning to obtain driving experience, this method can prevent agricultural vehicles from swinging back and forth due to improper angle adjustment, making the trajectory more stable and reliable.

The above patents all propose path planning methods for unmanned vehicles from different perspectives, but there are still certain defects: for example, the application scenario is only for a single farmland environment, which may lead to unnecessary redundant paths, and the planning path is slow. Based on the idea of changing space for time, the present invention provides a global path planning method and system for a large closed area, which can quickly obtain the required global path.

SUMMARY OF THE INVENTION

In view of the deficiencies in the prior art, the purpose of the present invention is to provide a method and system for global path planning in a closed area, and the purpose of the present invention is to overcome one or more of the above-mentioned deficiencies of the various methods.

To achieve the above purpose, the present invention provides the following technical solutions: a method for global path planning in a closed area, comprising the following steps:

Step S1, obtaining the environmental map model of the enclosed area and generating an intermediate connection path;

Step S2, obtaining the starting point and the target point of completing the job task;

Step S3, carry out corresponding global path planning according to the area where the starting point and the target point are located;

Step S4, controlling the vehicle to travel according to the planned global path;

Wherein, the environmental map of the enclosed area in step S1 may be a map of the area given by the dispatcher, or obtained from relevant map software, and the large enclosed area map is divided into two parts, including the operation area for completing various tasks and different In the connection area connected between the operation areas, there is at least one or more connection points at the junction of each operation area and the connection area. Connect the path and save it as a known path for later use.

As a further improvement of the present invention, in the step S2, the starting point is the current position of the vehicle, the position information is determined by the relevant GPS positioning system configured by the vehicle, and the target point is determined by the staff of the dispatch center according to the required driving tasks. The designated or unmanned control system is determined based on the current mission state of the vehicle. As a further improvement of the present invention, in the step S3, if the starting point and the target point are in the same operation area: according to the heading of the vehicle at the starting point and the desired parking direction at the target point, the multiple constraints of the minimum turning radius of the vehicle are satisfied. Under certain conditions, use the shortest arc curve or straight line or a mixture of both to connect the starting point and the target point as the driving path of the vehicle.

As a further improvement of the present invention, in the step S3, if the starting point and the target point are in different work areas, the global path from the starting point to the target point can be divided into the following three parts for three-stage global path planning :

(1) The first segment is the path from the starting point to the connection point between the operation area and the connection area. This segment of the path is based on the heading of the vehicle at the starting point and the heading of the vehicle at the connection point, and meets the minimum turning radius of the vehicle. Under the conditions, the shortest arc curve or straight line or a hybrid connection of the two is used as the driving path of the vehicle;

(2) The second segment of the path is the path between the connection point of the operation area and the connection area where the starting point is located to the connection point of the operation area and the connection area where the target point is located. This section of path can be quickly obtained by combining two connection points according to the known path of the connection area in step S1;

(3) The third path is the path from the connection point between the connection area and the area where the target point is located to the target point. This segment of the path is based on the heading at the entry junction and the desired parking direction at the target point. Under the condition that the minimum turning radius of the vehicle is satisfied, the shortest arc curve or straight line or a hybrid connection of the two is used as the driving path of the vehicle.

As a further improvement of the present invention, in the step S3, if the starting point is not in the operation area but in the connecting area, the global path from the starting point to the target point can be divided into the following three parts:

(1) The first segment is the path from the starting point to the tangent point entering the nearby known path in the connecting area. This segment of the path is based on the heading of the vehicle at the starting point and the heading at the tangent point where the vehicle enters the nearby known path. Under the condition that the minimum turning radius of the vehicle is met, the shortest arc curve or straight line or a hybrid connection of the two is used as the driving path of the vehicle;

(2) The second segment of the path is the path from the tangent point of the vehicle entering the nearby known path, along the known path, to the path between the work area where the target point is located and the connection point of the connection area. The path of this section can be quickly obtained according to the known path of the connection area in step S1;

(3) The third segment of the path is the path between the connection point between the connection area and the area where the target point is located to the target point. This segment of the path meets the minimum turning radius of the vehicle according to the heading at the entry connection point and the desired parking direction of the target point. Under the condition of , adopt the shortest arc curve or straight line or a hybrid connection of the two as the driving path of the vehicle.

The beneficial effect of the present invention is that through the settings of steps S1 to S4, global path planning in the closed area can be realized, and in step S1, the large closed area is divided into areas, and then the connection points between the divided areas are used. The connection path is generated according to the global path planning algorithm, and the space is exchanged for time, and the subsequent planning can quickly obtain the intermediate path. In this way, compared with the way of performing path planning for an entire area in the prior art, the property states of each area in a large closed area can be integrated to realize path planning, making the final planned path more rapid, reasonable and reliable.

Description of drawings

Fig. 1 is the flow chart of the present invention;

2 is a schematic diagram of a closed area according to an embodiment of the present invention;

3 is a schematic diagram of generating an intermediate connection road according to an embodiment of the present invention;

4 is a schematic diagram of the path planning when the starting point and the target point of the present invention are located in the same work area;

5 is a schematic diagram of the path planning when the starting point and the target point of the present invention are located in two different operation areas;

FIG. 6 is a schematic diagram of path planning when at least one of the starting point and the target point is located in the connection area according to the present invention.

Detailed ways

The present invention will be further described in detail below with reference to the embodiments given in the accompanying drawings.

As shown in the flowchart of FIG. 1, the present invention adopts the following technical solutions: a method and system for global path planning in a closed area, comprising the following steps:

S1 obtains the environmental map model of the enclosed area and generates intermediate connection paths

First, the environmental map of the enclosed area can be given by the dispatcher of the control center, or obtained from related map software.

As shown in Figure 2, the enclosed area can represent, but is not limited to, large enclosed areas such as ports, parks, mining areas, and farmland. The shaded part in Figure 2 represents the impassable area. The passable area of the enclosed area is mainly composed of two parts, including operation area 1, operation area 2, operation area 3, operation area 4, and different operation areas for completing various tasks. The intermediate road connection area of the connection.

A connection point is set at the junction of each operation area and the intermediate road connection area. In Figure 2, each junction is set with two connection points, such as A, B, C, D, E, F, M, N, Other embodiments may not be limited to two.

Then, in the connection area, for different operation areas, the global path planning algorithm is used to generate connection paths for the two connection points and save them as known paths for later use, thereby reducing the time required for subsequent path planning. The adopted global path planning algorithm may be an A* algorithm, a Dijkstra algorithm, or the like.

If the A* algorithm is used for global path planning, after obtaining the environmental map of the enclosed area at step S1, the map can be rasterized to form a rasterized environmental map model, which is convenient for the A* algorithm to search and obtain the optimal global path. Depending on the extent of the enclosed area environment model, an appropriate grid size can be selected. For example, a large enclosed area such as a port can choose a grid size of 0.5m or 1m.

FIG. 3 is a schematic diagram after the intermediate road connecting area of the closed area after step S1 generates an intermediate connecting path. The generated intermediate connection path is saved as a known path for later use. The idea of exchanging space for time is applied here, and storage space is used to exchange path planning time in the subsequent global path planning process.

S2 obtains the starting point and target point for completing the job task

The starting point for completing the task is generally the current position of the vehicle, and the position information can be determined by the relevant GPS positioning system configured on the vehicle; the target point can be designated by the staff of the dispatch center according to the required driving task or not. The human driving control system is determined according to the current task state of the vehicle.

S3 performs corresponding global path planning according to the area where the starting point and the target point are located

For the starting point and the target point obtained in step S2, according to the region positions of the starting point and the target point in the closed area, a corresponding global path planning is performed.

As shown in Figure 4, the starting point and the target point are located in the same work area.

According to the heading of the vehicle at the starting point S and the desired parking direction at the target point G, the shortest arc curve or straight line or a mixture of both is used to connect the starting point S and the target point G under the multiple constraints that satisfy the minimum turning radius of the vehicle. As the driving path SG of the vehicle.

As shown in Figure 5, the starting point and the target point are located in two different working areas. The starting point S is located in the working area 2, and the target point G is located in the working area 1. A three-segment path is used for global path planning.

(1) The first segment is the path SC from the starting point S to the connecting point C between the operation area 2 and the connecting area. This path is based on the heading of the vehicle at the starting point S and the heading of the vehicle at the connecting point C. Under the condition that the minimum turning radius of the vehicle is satisfied, the shortest arc curve or straight line or a hybrid connection of the two is used as the driving path of the vehicle.

(2) The second path is the path between the work area 2 where the starting point S is located and the connection point C of the connection area to the work area 1 where the target point G is located and the connection point B of the connection area. This segment of path CB can be obtained by combining two connection points C and B according to the known path of the connection area in step S1. Since the path CB obtained here has been obtained at step S1, it is not necessary to perform global path planning for the connection area based on connection points again, which saves planning time and obtains the path quickly.

(3) The third segment of the path is the path from the connection point B of the work area 1 where the connection area and the target point G are located to the target point G. The segment of the path BG is based on the heading at the incoming connection point B and the desired parking direction at the target point G. Under the condition that the minimum turning radius of the vehicle is satisfied, the shortest arc curve or straight line or a hybrid connection of the two is used as the driving path of the vehicle.

Since the vehicle headings at the connection points C and B are considered, the three-segment paths SC, CB, BG can be smoothly connected to the total global path SG at the two connection points C and B in turn.

As shown in FIG. 6 , the starting point S is located in the connection area instead of the work area, and the target point G is located in the work area 1 . Then select the adjacent intermediate path for global path planning.

(1) The first segment is the path from the starting point S to the tangent point L of the nearby known path in the connection area. This path is based on the heading of the vehicle at the starting point S and the tangent point L where the vehicle enters the nearby known path. Under the condition of satisfying the minimum turning radius of the vehicle, the shortest arc curve or straight line or a hybrid connection of the two is used as the driving path SL of the vehicle.

(2) The second segment of the path is the path from the tangent point L of the vehicle entering the nearby known path, along the known path, to the path between the work area where the target point is located and the connection point B of the connection area. The path LB of this segment can be obtained according to the known path of the connecting area in step S1. Since the path LB obtained here has been obtained in step S1, it is not necessary to perform global path planning for the connection area based on the connection point again, which saves planning time and obtains the path quickly.

(3) The third segment of the path is the path between the connection point B connecting the region and the region where the target point G is located to the target point G. The segment of the path BG is based on the heading at the incoming connection point B and the desired parking direction at the target point G. Under the condition that the minimum turning radius of the vehicle is satisfied, the shortest arc curve or straight line or a hybrid connection of the two is used as the driving path of the vehicle.

Since the vehicle headings at the tangent point L and the connection point B are considered, the three-segment paths SL, LB, BG can be smoothly connected to the total global path SG at the tangent point L and the connection point B in turn.

S4 controls the vehicle to travel according to the planned global path.

The vehicle driving control system controls the driving of the vehicle to complete the task according to the global path planned in step S3.

The above are only the preferred embodiments of the present invention, and the protection scope of the present invention is not limited to the above-mentioned embodiments, and all technical solutions under the idea of the present invention belong to the protection scope of the present invention. It should be pointed out that for those skilled in the art, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims (2)

1. a closed area global path planning method, is characterized in that: comprise the steps: Step S1, obtaining the environmental map model of the enclosed area and generating an intermediate connection path; Step S2, obtaining the starting point and the target point of completing the job task; Step S3, carry out corresponding global path planning according to the area where the starting point and the target point are located; Step S4, controlling the vehicle to travel according to the planned global path; Among them, the environmental map of the enclosed area in step S1 is given by the dispatcher, or obtained from relevant map software, and the large enclosed area map is divided into two parts, including the operation area for completing various tasks and different operations. In the connection area connected between areas, there is at least one or more connection points at the junction of each operation area and the connection area. In the connection area, for different operation areas, the global path planning algorithm is used to generate the connection between the two connection points. The path is saved as a known path for use; in the step S3, if the starting point and the target point are in the same operation area: according to the heading of the vehicle at the starting point and the desired parking direction at the target point, the minimum turning radius of the vehicle is satisfied Under the condition of multiple constraints, the shortest arc curve or straight line or a mixture of the two is used to connect the starting point and the target point as the driving path of the vehicle; In the step S3, if the starting point and the target point are in different work areas, the global path from the starting point to the target point is divided into the following three parts for three-stage global path planning: (1) The first segment is the path from the starting point to the connection point between the operation area and the connection area. This segment of the path is based on the heading of the vehicle at the starting point and the heading of the vehicle at the connection point, and meets the minimum turning radius of the vehicle. Under the conditions, the shortest arc curve or straight line or a hybrid connection of the two is used as the driving path of the vehicle; (2) The second path is the path between the connection point of the operation area and the connection area where the starting point is located to the connection point of the operation area and the connection area where the target point is located, and this segment of the path is combined according to the known path of the connection area in step S1. Two connection points can be obtained; (3) The third segment of the path is the path between the connection point between the connection area and the area where the target point is located to the target point. This segment of the path meets the minimum turning radius of the vehicle according to the heading at the entry connection point and the desired parking direction of the target point. Under the condition of , adopt the shortest arc curve or straight line or a hybrid connection of the two as the driving path of the vehicle; In the step S3, if the starting point is not in the work area but in the connecting area, the global path from the starting point to the target point is divided into the following three parts: (1) The first segment is the path from the starting point to the tangent point entering the nearby known path in the connecting area. This segment of the path is based on the heading of the vehicle at the starting point and the heading at the tangent point where the vehicle enters the nearby known path. Under the condition that the minimum turning radius of the vehicle is met, the shortest arc curve or straight line or a hybrid connection of the two is used as the driving path of the vehicle; (2) The second path is the path from the tangent point when the vehicle enters the nearby known path and starts along the known path to the path between the work area where the target point is located and the connection point of the connection area. A known path can be obtained; (3) The third segment of the path is the path between the connection point between the connection area and the area where the target point is located to the target point. This segment of the path meets the minimum turning radius of the vehicle according to the heading at the entry connection point and the desired parking direction of the target point. Under the condition of , adopt the shortest arc curve or straight line or a hybrid connection of the two as the driving path of the vehicle. 2. The global path planning method in a closed area according to claim 1, wherein in the step S2, the starting point is the current position of the vehicle, the position information is determined by the relevant GPS positioning system configured by the vehicle, and the target point is dispatched by The staff in the center designate according to the task of the driving operation to be completed or the unmanned control system determines the current task state of the vehicle.

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