Route planning method for intelligent obstacle avoidance based on regular route

Abstract

The invention provides a path planning method for intelligent obstacle avoidance based on a regular route, and the method sequentially comprises the steps: planning an original path, setting a temporary safe stop point, judging whether an obstacle disappears or not through time T, and if not, planning an obstacle avoidance path according to a virtual center point position O of the obstacle, a virtual circle of the obstacle and judgment of the distance between the left side and the right side, and then avoiding the obstacle according to the obstacle avoidance path, returning to the original path, and finally enabling the mobile robot to arrive at the terminal point. According to the method, whether the obstacle is removed or not is judged according to the time T, if the obstacle is removed, the robot walks according to the original path, and if the obstacle is not removed within the time T, the appropriate obstacle avoidance path can be selected to achieve walking of the mobile robot.

Description

Technical Field

[0001] The present invention relates to the technical field of route planning, and in particular to a path planning method for intelligent obstacle avoidance based on a prescribed route. Background Art

[0002] As an unmanned intelligent handling equipment, AGV plays an important role in manufacturing production, warehousing and logistics, etc. Among them, single-steering wheel AGV has the advantages of simple chassis structure, simple driving mode and low cost, and is widely used in the field of industrial logistics.

[0003] Among them, the path planning problem has always been one of the core issues in the intelligent research process of AGV cars. The path planning problem requires the AGV car to find an optimal or near-optimal path that can avoid obstacles in the working environment. It can be divided into global static path planning and local dynamic path planning.

[0004] For example, the patent document with Chinese patent application number 202310675275.4 and announcement date 2023.07.28 discloses a robot mobile obstacle avoidance method, device, equipment and medium, which are applied to a controller in the robot, and the method includes: responding to obstacle avoidance parameters and a planned path, constructing a constraint space and screening multiple radar points; after clustering and expanding the radar points, determining the blocking obstacles and sorting the blocking obstacles according to the obstacle index of the blocking obstacles on the planned path; if there is a non-blocking obstacle in front of the first blocking obstacle, performing an obstacle merging operation, and combining the constraint space to determine the obstacle avoidance start point and the obstacle avoidance end point on the planned path; determining multiple obstacle avoidance passing points according to the obstacle avoidance parameters and the obstacle vertex on the first blocking obstacle; using the obstacle avoidance start point, a single or two obstacle avoidance passing points and an obstacle avoidance end point to update the planned path, and moving the robot according to the new planned path, which can more effectively improve the robot's obstacle avoidance flexibility while ensuring that the robot's obstacle avoidance path is controllable.

[0005] However, the prior art of the above method avoids static obstacles, but cannot avoid dynamic obstacles. Some prior art can avoid dynamic obstacles, but it also needs to consider how to distinguish between dynamic obstacles and static obstacles. Moreover, the route planning methods in the prior art all adopt a more complex planning method, which may easily lead to the car being unable to reach the destination in the shortest and fastest way. Summary of the invention

[0006] The present invention provides a path planning method for intelligent obstacle avoidance based on a prescribed route; through this method, firstly, it is judged whether the obstacle has been removed by time T, if the obstacle is removed, the robot walks along the original path, if the obstacle is not removed within time T, a suitable obstacle avoidance path can be selected to realize the walking of the mobile robot.

[0007] To achieve the above object, the technical solution of the present invention is: a path planning method for intelligent obstacle avoidance based on a predetermined route, the specific steps of which include: S1 uses the mobile robot's laser radar to obtain surrounding environment information and form a grid map, and uses the A* algorithm to plan the original path of the mobile robot.

[0008] S2 The mobile robot continuously detects whether there are obstacles on the original path while walking along the original path. If an obstacle is detected, a temporary safe stopping point Q is determined between the mobile robot and the obstacle.

[0009] S3 The mobile robot stays at the temporary safety stop point Q for time T and continues to detect obstacles through the laser radar. If obstacles are detected within time T, S4 is performed. If the obstacle is detected to disappear within time T, the mobile robot continues to walk along the original path.

[0010] S4 plans the obstacle avoidance path, and its steps are as follows: S41 Calculate the coordinates of the virtual center point O of the obstacle based on the obstacle coordinate information scanned by the laser radar (x k ,y k ); obstacle virtual center point (x k ,y k ) is the average value of the obstacle coordinates obtained by scanning.

[0011] S42 obtains the coordinate point (x z ,y z ).

[0012] S43 According to (x k ,y k ) and (x z ,y z ) Calculate the radius r of the virtual obstacle circle with the virtual center point of the obstacle as the center.

[0013] S44 Determine the coordinates (x a ,y a ) and the coordinates of the obstacle virtual circle and the end point B of the original obstacle avoidance path (x b ,y b ).

[0014] S45 takes the virtual center point O of the obstacle as the center of the circle and r as the radius, and determines the size of the distance L1 from point A to point B on the left side of the original path and the distance L2 from point A to point B on the right side of the original path. If L1≤L2, an obstacle avoidance path is planned on the left side of the original path. If L1>L2, an obstacle avoidance path is planned on the right side of the original path.

[0015] S46 forms a virtual circle with the virtual center point O as the center and R as the radius, and forms an obstacle avoidance path according to the virtual circle arc with the orientation determined in S45, where R=r+r1+j, r1 is the maximum radius of the mobile robot, and j is the safe distance between the virtual circle of the obstacle formed by r and the virtual circle of the mobile robot formed by r1.

[0016] The above method first plans the original path of the mobile robot through the A* algorithm. During the walking process, if the mobile robot does not encounter an obstacle, it walks along the original path. If it encounters an obstacle, it plans an obstacle avoidance path according to the invention of the present invention. In the present invention, when the mobile robot encounters an obstacle, a temporary safety stop point Q is set and the time T is used to determine whether the obstacle has disappeared. If the obstacle has disappeared, it continues to walk along the original path. If the obstacle has not disappeared, an obstacle avoidance path is planned, so that the mobile robot can reach the end point smoothly. When planning an obstacle avoidance path, firstly, the coordinates of the virtual center point O of the obstacle are determined according to the method of the present invention, and then a virtual circle of the obstacle is determined with the coordinates of the virtual center point O of the obstacle as the center, and a suitable obstacle avoidance path of the mobile robot is determined through S44, S45 and S46, so that the mobile robot passes through point Q via the intersection of the obstacle avoidance path and the original path behind the obstacle, and then quickly reaches the intersection of the obstacle avoidance path, the obstacle avoidance path behind the obstacle and the original path via the obstacle avoidance path, returns to the original path, and then continues to walk along the original path. On the one hand, when the mobile robot encounters an obstacle, a suitable obstacle avoidance path can be planned to allow the mobile robot to reach the end point smoothly, and on the other hand, it can avoid the mobile robot from colliding with the obstacle when passing through the obstacle avoidance path.

[0017] Further, the original path point at a distance Hm from the obstacle is set as a temporary safety stop point Q. This method determines the temporary safety stop point by setting a fixed distance Hm, and the operation is simple and fast.

[0018] Furthermore, in S41,

[0019] (x i ,y i ) is the obstacle coordinate information, i is the i-th position point on the obstacle, and m is the total number of points in the horizontal and vertical directions of obstacle detection. This invention forms (x k,y k ), then (x k ,y k ) The coordinate points have high accuracy.

[0020] Further, in S42, the coordinate point (x k ,y k ) is mapped to the map used by the A* algorithm to plan the original path of the mobile robot, with coordinate points (x k ,y k ) is the center of the circle and the edge of the obstacle is scanned by the laser radar. The edge of the obstacle scanned by the laser radar is 100 meters from the coordinate point (x k ,y k ) is determined as the coordinate point (x z ,y z This can more accurately determine the coordinate point (x z ,y z ).

[0021] Furthermore, in S43, the radius r of the virtual obstacle circle is calculated as follows:

[0022] Furthermore, the intersection point of the starting point of the original obstacle avoidance path and the virtual obstacle circle is determined as A, and the intersection point of the end point of the original obstacle avoidance path and the virtual obstacle circle is determined as B. Determining points A and B facilitates the calculation of L1 and L2, and the appropriate obstacle avoidance path is determined by comparing the lengths of L1 and L2.

[0023] Further, in S45, the following steps are used to calculate L1 and L2: S451 Calculate the chord length S based on the coordinates from point A to point B.

[0024] S452 determines whether S is equal to 2r. If S=2r, an obstacle avoidance path is planned on the left side of the original path. If S≠2r, the minor arc length L0 corresponding to the chord length S is calculated.

[0025] Among them, L0

[0026] S453 determines which side of the original path the inferior arc is located on. If the inferior arc is located on the left side of the original path, L0 represents L1, and L1 < L2. An obstacle avoidance path is planned on the left side of the original path. If the inferior arc is located on the right side of the original path, L0 represents L2, and L1 > L2. An obstacle avoidance path is planned on the right side of the original path. In this way, a shorter obstacle avoidance path can be determined.

[0027] Furthermore, the position of the minor arc is determined by comparing any coordinate on the minor arc with the coordinate on the original path.

[0028] Furthermore, if the length of the mobile robot is set to L and the width of the mobile robot is set to W, then This method can determine the maximum radius of the mobile robot.

[0029] Furthermore, after the mobile robot moves to the intersection point C with the original path located in front of the obstacle according to the obstacle avoidance path, it moves to the end point along the original path with point C as the starting point. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a schematic diagram of the original path.

[0031] Figure 2 Schematic diagram of obstacles encountered.

[0032] Figure 3 Schematic diagram of determining L1 and L2 through obstacles.

[0033] Figure 4 Schematic diagram for determining obstacle avoidance routes. DETAILED DESCRIPTION

[0034] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0035] A path planning method for intelligent obstacle avoidance based on a prescribed route, the specific steps comprising: S1 Figure 1 As shown, the laser radar of the mobile robot is used to obtain the surrounding environment information and form a grid map 200, and the A* algorithm is used to plan the original path 1 of the mobile robot 100 from the starting point G1 to the end point G2. This method is an existing technology for determining the original path of the mobile robot, which will not be repeated here.

[0036] S2 The mobile robot 100 continuously detects whether there are obstacles on the original path while walking along the original path, such as Figure 2 As shown, if an obstacle 2 is detected, a temporary safety stop point Q is determined between the mobile robot 100 and the obstacle 2. In this step, the original path point at a distance Hm from the obstacle is set as the temporary safety stop point Q. This method determines the temporary safety stop point by setting a fixed distance Hm, which is simple and fast to operate. The H is pre-set in the mobile robot, and m is a unit of length. Generally, H=L / 2+L3, L is the length of the mobile robot, and L3 is the distance from the front end of the mobile robot to the rear end of the obstacle. In this embodiment, it can be set to 0.5m.

[0037] S3 The mobile robot 100 stays at the temporary safety stop point Q for time T and continues to detect obstacle 2 through the laser radar. If obstacle 2 is detected within time T, S4 is performed. If the obstacle disappears within time T, the mobile robot 100 continues to walk along the original path 1. In this embodiment, T can be set to 10S or other time as needed.

[0038] S4 plans the obstacle avoidance path, and its steps are as follows: S41 Figure 3 As shown in the figure, the coordinates of the virtual center point O of the obstacle are calculated based on the coordinate information of obstacle 2 scanned by the laser radar (x k ,y k ); obstacle virtual center point (x k ,y k ) is the average value of the obstacle coordinates obtained by scanning. The specific method is:

[0039] Among them, (x i ,y i ) is the obstacle coordinate information, i is the i-th position point on the obstacle, and m is the total number of points in the horizontal and vertical directions of obstacle detection. This invention forms (x k ,y k ), then (x k ,y k ) The coordinate points have high accuracy.

[0040] S42 obtains the coordinate point (x z ,y z In this step, the coordinate point (x k ,y k ) is mapped to the map used by the A* algorithm to plan the original path of the mobile robot, with coordinate points (x k ,y k ) is the center of the circle and the edge of the obstacle is scanned by the laser radar. The edge of the obstacle scanned by the laser radar is 100 meters from the coordinate point (x k ,y k ) is determined as the coordinate point (x z ,y z This can more accurately determine the coordinate point (x z ,y z ) S43 According to (x k ,y k ) and (x z ,y z) Calculate the radius r of the virtual obstacle circle with the virtual center point of the obstacle as the center. The calculation method of the radius r of the virtual obstacle circle is:

[0041] S44 Determine the coordinates (x a ,y a ) and the coordinates of the obstacle virtual circle and the end point B of the original obstacle avoidance path (x b ,y b ). In this step, when the obstacle virtual circle is determined, the intersection point of the starting point of the original obstacle avoidance path and the obstacle virtual circle is determined as A, and the intersection point of the end point of the original obstacle avoidance path and the obstacle virtual circle is determined as B. In the present invention, the original obstacle avoidance path refers to the path between the two intersection points of the original path and the obstacle virtual circle, that is, the original path between segment A and segment B.

[0042] S45: With the virtual center point O of the obstacle as the center and r as the radius, determine the size of the distance L1 from point A to point B on the left side of the original path and the distance L2 from point A to point B on the right side of the original path. If L1≤L2, then plan an obstacle avoidance path on the left side of the original path. If L1>L2, then plan an obstacle avoidance path on the right side of the original path. The specific steps are: S451 Calculate the chord length S based on the coordinates from point A to point B.

[0043] S452 determines whether S is equal to 2r. If S=2r, an obstacle avoidance path is planned on the left side of the original path. If S≠2r, the minor arc length L0 corresponding to the chord length S is calculated.

[0044] Among them, L0 .

[0045] S453 Determine which side of the original path the inferior arc is located on. If the inferior arc is on the left side of the original path, L0 represents L1, and L1 < L2. An obstacle avoidance path is planned on the left side of the original path. If the inferior arc is on the right side of the original path, L0 represents L2, and L1 > L2. An obstacle avoidance path is planned on the right side of the original path. In this way, a shorter obstacle avoidance path can be determined. Figure 3 It can be seen that in this embodiment, L1>L2, then the obstacle avoidance path is planned from the right side of the original path.

[0046] S46 Figure 4As shown, a virtual circle is formed with the virtual center point O as the center and R as the radius, and an obstacle avoidance path 3 is formed according to the virtual circle arc of the orientation determined in S45, where R=r+r1+j, where r1 is the maximum radius of the mobile robot, and j is the safe distance between the obstacle virtual circle formed by r and the mobile robot virtual circle formed by r1. 0.5m or other data can be selected, as long as j is set to prevent the mobile robot from colliding with obstacles. In this step, the length of the mobile robot is set to L, and the width of the mobile robot is set to W, then This method can determine the maximum radius of the mobile robot.

[0047] After the mobile robot 100 moves to the intersection point C with the original path in front of the obstacle according to the obstacle avoidance path 3, it moves to the end point G2 along the original path starting from point C. In this way, the mobile robot can reach the end point smoothly.

[0048] The method of this embodiment first plans the original path of the mobile robot through the A* algorithm. During the walking process, if the mobile robot does not encounter an obstacle, it walks along the original path. If it encounters an obstacle, it plans an obstacle avoidance path according to the invention of the present invention. In the present invention, when the mobile robot encounters an obstacle, a temporary safety stop point Q is set and the time T is used to determine whether the obstacle has disappeared. If the obstacle has disappeared, it continues to walk along the original path. If the obstacle has not disappeared, an obstacle avoidance path is planned, so that the mobile robot can reach the end point smoothly. When planning an obstacle avoidance path, firstly, the coordinates of the virtual center point O of the obstacle are determined according to the method of the present invention, and then a virtual circle of the obstacle is determined with the coordinates of the virtual center point O of the obstacle as the center, and a suitable obstacle avoidance path of the mobile robot is determined through S44, S45 and S46, so that the mobile robot passes through point Q via the intersection of the obstacle avoidance path and the original path behind the obstacle, and then quickly reaches the intersection of the obstacle avoidance path, the obstacle avoidance path behind the obstacle and the original path via the obstacle avoidance path, returns to the original path, and then continues to walk along the original path. On the one hand, when the mobile robot encounters an obstacle, a suitable obstacle avoidance path can be planned to allow the mobile robot to reach the end point smoothly, and on the other hand, it can avoid the mobile robot from colliding with the obstacle when passing through the obstacle avoidance path.

Claims

1. A path planning method for intelligent obstacle avoidance based on a prescribed route, characterized in that: The specific steps include: S1 uses the mobile robot's laser radar to obtain surrounding environment information and form a grid map, and uses the A* algorithm to plan the original path of the mobile robot; The S2 mobile robot continuously detects whether there are obstacles on the original path while walking along the original path. If an obstacle is detected, a temporary safe stopping point Q is determined between the mobile robot and the obstacle; S3: The mobile robot stays at the temporary safety stop point Q for time T and continues to detect obstacles through the laser radar. If obstacles are detected within time T, S4 is performed. If obstacles are detected to disappear within time T, the mobile robot continues to walk along the original path. S4 plans the obstacle avoidance path, and its steps are as follows: S41 Calculate the coordinates of the virtual center point O of the obstacle based on the obstacle coordinate information scanned by the laser radar (x k ,y k ); obstacle virtual center point (x k ,y k ) is the average value of the obstacle coordinates obtained by scanning; S42 obtains the coordinate point (x z ,y z ); S43 According to (x k ,y k ) and (x z ,y z ) Calculate the radius r of the virtual obstacle circle with the virtual center point of the obstacle as the center; S44 Determine the coordinates (x a ,y a ) and the coordinates of the obstacle virtual circle and the end point B of the original obstacle avoidance path (x b ,y b ); S45 takes the virtual center point O of the obstacle as the center of the circle and r as the radius, and determines the size of the travel L1 from point A to point B on the left side of the original path and the travel L2 from point A to point B on the right side of the original path. If L1≤L2, an obstacle avoidance path is planned on the left side of the original path. If L1>L2, an obstacle avoidance path is planned on the right side of the original path. S46 forms a virtual circle with the virtual center point O as the center and R as the radius, and forms an obstacle avoidance path according to the virtual circle arc with the orientation determined in S45, where R=r+r1+j, r1 is the maximum radius of the mobile robot, and j is the safe distance between the virtual circle of the obstacle formed by r and the virtual circle of the mobile robot formed by r1.

2. The path planning method for intelligent obstacle avoidance based on a predetermined route according to claim 1, characterized in that: Set the original path point at the obstacle Hm as the temporary safe stop point Q.

3. The path planning method for intelligent obstacle avoidance based on a predetermined route according to claim 1, characterized in that: In S41, (x i ,y i ) is the obstacle coordinate information, i is the i-th position point on the obstacle, and m is the total number of points in the horizontal and vertical directions of obstacle detection.

4. The path planning method for intelligent obstacle avoidance based on a predetermined route according to claim 1, characterized in that: In S42, the coordinate point (x k ,y k ) is mapped to the map used by the A* algorithm to plan the original path of the mobile robot, with coordinate points (x k ,y k ) is the center of the circle and the edge of the obstacle is scanned by the laser radar. The edge of the obstacle scanned by the laser radar is 100 meters from the coordinate point (x k ,y k ) is determined as the coordinate point (x z ,y z ).

5. The path planning method for intelligent obstacle avoidance based on a predetermined route according to claim 1, characterized in that: In S43, the radius r of the virtual obstacle circle is calculated as follows: 。 6. The path planning method for intelligent obstacle avoidance based on a predetermined route according to claim 1, characterized in that: The intersection point of the starting point of the original obstacle avoidance path and the virtual circle of the obstacle is determined as A, and the intersection point of the end point of the original obstacle avoidance path and the virtual circle of the obstacle is determined as B.

7. The path planning method for intelligent obstacle avoidance based on a predetermined route according to claim 1, characterized in that: In S45, L1 and L2 are calculated using the following steps: S451 Calculate the chord length S based on the coordinates from point A to point B. ； S452 determines whether S is equal to 2r. If S=2r, an obstacle avoidance path is planned on the left side of the original path. If S≠2r, the length of the minor arc L0 corresponding to the chord length S is calculated. in, ; S453 determines which side of the original path the inferior arc is located on. If the inferior arc is on the left side of the original path, L0 represents L1, and L1<L2. An obstacle avoidance path is planned on the left side of the original path. If the inferior arc is on the right side of the original path, L0 represents L2, and L1>L2. An obstacle avoidance path is planned on the right side of the original path.

8. The path planning method for intelligent obstacle avoidance based on a predetermined route according to claim 7, characterized in that: The position of the minor arc is determined by comparing any coordinate on the minor arc with the coordinate on the original path.

9. The path planning method for intelligent obstacle avoidance based on a predetermined route according to claim 1, characterized in that: Let the length of the mobile robot be L and the width of the mobile robot be W. .

10. The path planning method for intelligent obstacle avoidance based on a predetermined route according to claim 1, characterized in that: When the mobile robot moves to point C, the intersection of the original path in front of the obstacle, according to the obstacle avoidance path, it moves to the end point along the original path starting from point C.

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