CN115686010A - Path planning method, path planning device, electronic device, and storage medium - Google Patents

Abstract

The invention provides a path planning method, a path planning device, an electronic device and a storage medium. The path planning method is used for planning the driving path of the robot on a working site, and is characterized by comprising the following steps: acquiring a global map of a work site in two-dimensional representation; setting an area in the global map, which represents an obstacle and is within a range having a predetermined distance from the periphery of the obstacle, as an avoidance area; and planning the driving path of the robot by taking the geometric center of the robot in the two dimensions as a representative robot point so as to prevent the representative robot point from entering the avoidance area in the global map.

Description

Path planning method, path planning device, electronic device, and storage medium

Technical Field

The present invention relates to the field of path planning for robots, and in particular, to a path planning method, a path planning apparatus, an electronic device, and a storage medium.

Background

In recent years, with the development of smart factories, the use of automatic navigation robots has become widespread. As an example of an automatic navigation robot, an AGV (Automated Guided Vehicle) is widely used in many factories and laboratories today due to its good adaptability, flexibility, and benefit for secondary development and integration. The AGV group is adopted to replace labor cost, so that labor force can be liberated, and semi-automation and automation of an intelligent factory are realized.

For an automatic AGV routing method (path planning method), there are various algorithms such as a-x algorithm and D-x algorithm, and usually, an optimal path with the shortest length or the smallest cost is automatically planned between a starting point and a target point in a certain environment by using these algorithms.

However, in these routing algorithms, the AGVs are generally treated as particles theoretically at present, the actual collision volumes of the AGVs are not considered, and it is obvious that the particle treatment cannot be performed in the actual factory or laboratory, and the obtained paths should be paths after the collision volumes are considered. In the current actual operation work, the AGV uses its own model, and calculates the collision volume of the AGV itself and calculates the routing algorithm a or D at each position in the calculation process, so as to obtain the final optimal path. However, in this way, since it is necessary to evaluate whether the vehicle body and the obstacle will collide at the next moment in real time during the road-finding algorithm, the time complexity is greatly increased during the calculation, and the calculation amount is large.

In addition, in the above algorithm, all are explicit scenarios for the starting point and the target point, and the target point can be reached directly by the AGV. However, in the case of using the hybrid robot, there is a high possibility that the target point is on one table, and in this case, it is only necessary to stop the AGV near the table and then operate the target object by the robot arm provided to the AGV. Therefore, the path to be found does not need to reach the target point, but only needs to find a position where the robot arm can reach the target point, and the AGV can go to the position with the optimal path. Therefore, the traditional path-finding algorithm cannot be completely applied to the composite robot.

Disclosure of Invention

The present invention has been made in view of the above problems, and an object of the present invention is to solve at least one of the above problems and to provide a path planning method, a path planning apparatus, an electronic device, and a storage medium, which are capable of reducing the amount of computation while considering the collision volume and which are capable of coping with a hybrid robot.

According to a first aspect of the present invention, there is provided a path planning method for planning a travel path of a robot at a work site, comprising: acquiring a global map of a work site in two-dimensional representation; setting an area in the global map, which represents an obstacle and is within a range having a predetermined distance from the periphery of the obstacle, as an avoidance area; and planning the driving path of the robot by taking the geometric center of the robot in the two dimensions as a robot representative point so that the robot representative point does not enter the avoidance area in the global map.

In some embodiments, the travel path is planned in such a way that the robot representative point travels from a starting point to a target area with a shortest distance or a minimum cost, wherein the target area is an area within a prescribed radius from a target point and is not the avoidance area.

In some embodiments, the prescribed distance is the longest distance from the geometric center to a point on the outer perimeter of the robot.

In some embodiments, the robot is a compound robot having a robotic arm, and the prescribed radius is a maximum working radius of the robotic arm.

In some embodiments, the global map is a map obtained by arranging a plurality of pixels according to a two-dimensional matrix, the pixels in the avoidance region are set as an avoidance point set, the pixels in the target region are set as a target point set, and the following steps are performed during path planning: the first step, adding the starting point into a list to be traversed; a second step of searching a point with the minimum distance evaluation value from the target point, namely a target point, in the list to be traversed; a third step of performing breadth-first search on the object point, adding points except traversed points and unreachable points, namely new points, of eight surrounding pixel points to the list to be traversed, removing the object point from the list to be traversed, and setting the object point as a parent node of the new points; and a fourth step of repeating the second step and the third step, and when an end point, which is any one point in the target point set, is traversed, tracing back from the end point to the start point along the parent node, and setting a path from the start point to the end point obtained by tracing back the end point to the start point as the travel path, or when the list to be traversed is empty, determining that there is no travel path that can reach the target area.

According to a second aspect of the present invention, there is provided a path planning apparatus for planning a travel path of a robot at a work site, the apparatus comprising: an acquisition module configured for acquiring a global map of the work site in a two-dimensional representation; a setting module configured to set, as an avoidance area, an area in the global map that represents an obstacle and is within a range that is a predetermined distance from an outer periphery of the obstacle; and a planning module configured to plan the travel path of the robot by using a geometric center of the robot in the two dimensions as a robot representative point so that the robot representative point does not enter the avoidance area in the global map.

According to a third aspect of the present invention, an electronic device is provided. The electronic device includes a processor and a memory storing a computer program, and the processor executes the computer program to cause the electronic device to execute the path planning method according to the first aspect.

According to a fourth aspect of the present invention, a storage medium is provided. The storage medium stores a computer program for causing a computer to execute the path planning method according to the first aspect.

Effects of the invention

According to the present invention, it is possible to provide a path planning method, a path planning device, an electronic device, and a storage medium that can reduce the amount of computation while considering the collision volume and can cope with a hybrid robot.

It should be understood that the statements herein reciting aspects are not intended to limit the critical or essential features of any embodiment of the invention, nor are they intended to limit the scope of the invention. Other features of the present invention will become apparent from the following description.

Drawings

The above and other features, advantages and aspects of embodiments of the present invention will become more apparent upon consideration of the following detailed description, taken in conjunction with the accompanying drawings. In the drawings, like or similar reference characters designate like or similar elements, and wherein:

fig. 1 is a diagram schematically showing an example of a two-dimensional global map of a work site.

Fig. 2 shows a schematic flow diagram of a path planning method according to an embodiment of the invention.

Fig. 3 is a schematic view showing a set avoidance region according to an embodiment of the present invention.

FIG. 4 is a schematic block diagram illustrating the path planner of the present invention;

fig. 5 is a simplified block diagram illustrating an electronic device of the present invention.

Detailed Description

Embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. While certain embodiments of the present invention have been illustrated in the accompanying drawings, it is to be understood that the present invention may be embodied in various forms and should not be construed as limited to the embodiments set forth herein, but rather is provided for a more thorough and complete understanding of the present invention. It should be understood that the drawings and the embodiments of the present invention are illustrative only and are not intended to limit the scope of the present invention.

The terms "include" and variations thereof as used herein are inclusive and open-ended, i.e., "including but not limited to. The term "based on" is "based, at least in part, on". The term "one embodiment (implementation)" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment". Relevant definitions for other terms will be given in the following description.

It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of the embodiments. As used herein, the term "and/or" includes any and all combinations of one or more of the listed terms.

As described above, in the current path planning method, the automatic navigation robot mostly uses its own model, and in the calculation process, each position performs the calculation of its own collision volume plus the calculation of the a or D routing algorithm, so as to obtain the final optimal path, and the calculation amount is large. Moreover, for the case of a composite robot with a mechanical arm, the conventional way-finding algorithm is not completely applicable.

In view of this, embodiments of the present invention provide a solution that can reduce the amount of computation while taking into account the collision volume. In the scheme, an envelope curve is set for obstacles in a global map of a scene, and an area in the envelope curve is used as an avoidance area, so that the problem that the automatic navigation robot collides due to the volume of the automatic navigation robot is solved. Moreover, the scheme capable of coping with the composite robot is provided. In the scheme, the path-finding success condition is improved from a specific coordinate to a target point set which is restricted by a human so as to meet the actual requirement.

Fig. 1 is a diagram schematically showing an example of a two-dimensional global map of a work site. As shown in fig. 1, the global map is a two-dimensional map in an overhead view showing an actual state of a work site, and includes an AGV as an example of a robot, a start point S as an initial position of the AGV, an obstacle Z existing in the work site, and a travel destination of the AGV. Here, the starting point S is a position where a geometric center C (hereinafter, also referred to as a representative robot point C) of the AGV in two dimensions is initially located.

In fig. 1, the AGV is shown as an example of a robot, but the present invention is not limited to this, and may be any robot that can automatically seek a route and travel from a starting point S to a destination. The two-dimensional shape of the robot in plan view is not limited to the rectangular shape shown in the drawings, and may be other shapes such as a circular shape. Although only one rectangular obstacle Z is shown in fig. 1 for convenience of explanation, the shape, number, position, and the like of the obstacles are not particularly limited, and the shape, number, position, and the like of the obstacles in an actual work scene may be various.

Fig. 2 is a schematic flow chart diagram illustrating a path planning method 100 of one embodiment of the present invention. It should be noted that the path planning method 100 may include other additional steps not shown, or may omit some of the steps shown. The scope of the invention is not limited in this respect. The route planning method 100 according to the present embodiment will be described in detail below.

The path planning method 100 is used for planning a driving path of an AGV at a work site, and the path planning method 100 may be executed in the AGV, may also be executed in an upper computer of the AGV, and may also be executed in a part of each of the AGV and the AGV, which is not particularly limited.

As shown in fig. 2, a two-dimensional global map of the work site is acquired (step S1). The global map may be acquired by, for example, inputting by a worker before starting the route planning, but the present invention is not limited to this, and the global map may be created by providing an AGV with a route search function implemented by a camera, a sensor, or the like, and acquiring a situation of a work site such as distribution of obstacles by searching the AGV in advance at the work site. In the present embodiment, for convenience, an example in which an obstacle is a fixed obstacle is described, but the present invention is not limited to this, and the present invention can be applied to a case in which an obstacle is moved.

Next, an avoidance area B is set in the global map (step S2). Fig. 3 is a schematic view showing a set avoidance region according to an embodiment of the present invention. As shown in fig. 3, in the present embodiment, the avoidance area B is an area in the global map that indicates the obstacle Z and a range that is a predetermined distance d from the outer periphery of the obstacle Z. In other words, an envelope is set at a distance d along the outer periphery of the obstacle Z, and a region within the envelope is the escape region B. As described later, the avoidance area B is an area where the representative point of the robot cannot enter (reach) when the path is planned.

In the present embodiment, the predetermined distance d is the longest distance from the geometric center C of the AGV to a point on the outer periphery of the AGV. For example, in the case where the two-dimensional shape of the AGV is a rectangle, as shown in fig. 3, the distance d is defined as a distance from the geometric center C of the AGV to one corner thereof, i.e., a length of half of a diagonal line. By setting the predetermined distance d in this manner, the range of the avoidance region can be restricted to a small range while ensuring the collision distance, and the planning efficiency can be improved.

The predetermined distance d is not limited to be equal to the longest distance, and may be slightly longer than the longest distance to prevent the AGV from colliding with the obstacle, for example, in order to provide a margin.

After the avoidance area B is set, the travel path of the AGV on the global map is planned (step S3). Specifically, the travel path of the AGV is planned by considering the two-dimensional geometric center C of the AGV as a mass point representing the AGV (hereinafter, also referred to as a representative robot point C) so that the representative robot point C does not enter the avoidance area B on the global map.

As described above, by setting the avoidance region B, the entire region (avoidance region) including the obstacle Z and taking into account the collision volume of the AGVs is treated as an obstacle substantially at the time of path planning, and thus, even if the AGVs are considered as particles, collision does not occur due to the problem of the AGVs own volume, and it is not necessary to calculate the own collision volume at each position in the calculation process and add calculation of an algorithm such as a route finding algorithm or D, and the calculation amount can be reduced while taking into account the collision volume.

In the present embodiment, the travel destination of the AGV is not one point but one area, for example. Specifically, as shown in fig. 1, the travel destination of the AGV is a target area E, that is, in the path planning, the travel path is planned such that the representative robot point C travels from the start point S to the target area E with the shortest distance or the smallest cost.

Here, as shown in fig. 1, the target area E is an area which is within a range of a predetermined radius R from the target point P and is not the avoidance area B. In the present embodiment, the AGV is a hybrid robot including an arm, and the predetermined radius R is the maximum working radius of the arm of the hybrid robot. That is, the AGV can reach the position of the target point P by the robot arm when located at any point within the target area E. For example, when the target point P is located on the table, the avoidance area is set for the table as an obstacle, and therefore, in this case, the target area E is an area excluding the avoidance area set for the table as described above.

By setting the travel destination of the AGV to one area instead of one point in this way, the hybrid robot can be handled, and the path planning can be performed more efficiently.

The predetermined radius R is not limited to the maximum operating radius of the robot arm, and may be smaller than the maximum operating radius, that is, the AGV located in the target area E can reach the target point P by the robot arm, for example, in order to provide a margin.

In addition, as for the specific algorithm used when planning the travel path, various known algorithms can be adopted as needed as long as the above-described scheme can be satisfied. As an example, a method of planning a route using the a-star algorithm according to an embodiment of the present invention will be described below.

First, a map (global map) of a work site in which a plurality of pixels are arranged in a two-dimensional matrix is obtained. Attributes such as whether the pixels are obstacle pixels or not, weights in the route finding process, and the like can be set for each pixel in the global map.

And setting the pixel point where the geometric center point of the AGV is initially located as a starting point in the global map, and setting all the pixel points of the target area as a target point set. Then, all the pixels in a region (avoidance region) indicating the obstacle and a range having a predetermined distance from the outer periphery of the obstacle are set as an avoidance point set.

After the setting of the starting point and each point set is completed, path planning is carried out, and specifically, the following steps are carried out:

the method comprises the following steps that firstly, a starting point S is added into a list to be traversed (open list);

a second step of finding a point with the minimum distance evaluation value of the target point P, namely a target point, in the list to be traversed (only a starting point is found at first);

a third step of performing breadth-first search on the object point, adding points except traversed points and unreachable points in eight surrounding pixel points (right, upper left, lower right) to the list to be traversed, namely new points, removing the object point from the list to be traversed, and setting the object point as a parent node of the new points;

and a fourth step of repeating the second step and the third step, and when an end point, which is any one point in the target point set, is traversed, tracing back from the end point to the start point along the parent node, and setting a path from the start point to the end point obtained by tracing back to the start point as a travel path, or when the list to be traversed is empty, determining that there is no travel path that can reach the target area.

Through the above processing, when the AGV is considered as a mass point, a travel path for traveling from the start point to the target area at the shortest distance or the smallest cost can be easily planned, and the hybrid robot can be handled while reducing the amount of computation in consideration of the collision volume.

Fig. 4 shows a schematic block diagram of a path planner 200 according to an embodiment of the invention. It is to be understood that the path planner 200 may include additional components than those shown or omit some of the components shown therein, as the present invention is not limited in this respect.

As shown in fig. 4, the path planning apparatus 200 includes an acquisition module 210, a setting module 220, and a planning module 230. The acquisition module 210 is configured for acquiring a global map of the work site in a two-dimensional representation. The setting module 220 is configured to set, as an avoidance area, an area in the global map that represents the obstacle and is within a range that is a predetermined distance from the outer periphery of the obstacle. The planning module 230 is configured to plan a travel path of the robot by using a geometric center of the robot in two dimensions as a robot representative point so that the robot representative point does not enter an avoidance area in the global map.

Details of the acquisition of the global map, the setting of the avoidance area, the planning of the route, and the like can be the same as those described above, for example, and therefore, redundant description is omitted.

The route planning device 200 of the present invention may be provided for each robot, may be provided in a host computer of the robot, or may be provided in part of each of the two, and is not particularly limited.

Fig. 5 shows a simplified block diagram of an electronic device 500 suitable for implementing an embodiment of the invention. The electronic device 500 may be seen as a further illustrative embodiment of the path planner 200 shown in fig. 4. Thus, the electronic device 200 can be implemented in at least a portion of the path planner 200 or as a portion of the path planner 200.

As shown in fig. 5, the electronic device 500 includes one or more processors 510, one or more memories 520 coupled to the processors 510, and one or more communication modules 540 coupled to the processors 510.

The communication module 540 is used for bidirectional communication. The communication module 540 has a communication interface to facilitate communication. A communication interface may represent any interface necessary to communicate with other network elements.

Processor 510 may be of any type suitable for a local technology network, and may include one or more of the following, as limiting examples: general purpose computers, special purpose computers, microprocessors, digital network flash memory, and processors based on a multi-core processor architecture. The electronic device 500 may have multiple processors, such as application specific integrated circuit chips, that are time-dependent from a clock synchronized with the main processor.

Memory 520 may include one or more non-volatile memories and one or more volatile memories. Examples of non-volatile memory include, but are not limited to, read Only Memory (ROM) 524, electrically Programmable Read Only Memory (EPROM), flash memory, a hard disk, a Compact Disk (CD), a Digital Video Disk (DVD), and other magnetic storage and/or optical storage devices. Examples of volatile memory include, but are not limited to, random Access Memory (RAM) 522 and other volatile memory that does not persist for the duration of the power loss.

The computer programs 530 include computer-executable instructions that are executed by the associated processor 510. A computer program 530 may be stored in the ROM 524. Processor 510 may perform any suitable actions and processes by loading computer programs 530 into RAM 522.

Embodiments of the invention may be implemented by means of a computer program 530 such that the electronic device 500 may perform any of the processes of the invention as discussed with reference to fig. 2. Embodiments of the present invention may also be implemented by hardware or by a combination of software and hardware.

In some embodiments, the computer program 530 may be tangibly embodied in a computer-readable medium, which may be included in the device 500 (such as in the memory 520) or other storage device accessible by the device 500. The computer program 530 may be loaded from a computer-readable medium into RAM 522 for execution. The computer readable medium may include any type of tangible, non-volatile memory, such as a ROM, EPROM, flash memory, hard disk, CD, DVD, etc.

In general, the various exemplary embodiments of this invention may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Certain aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device. While various aspects of the embodiments of the invention may be illustrated and described as block diagrams, flow charts, or using some other pictorial representation, it is well understood that the blocks, apparatus, systems, techniques or methods described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof. Examples of hardware devices that may be used to implement embodiments of the present invention include, but are not limited to: field Programmable Gate Arrays (FPGAs), application Specific Integrated Circuits (ASICs), application Specific Standard Products (ASSPs), systems on a chip (SOCs), complex Programmable Logic Devices (CPLDs), and the like.

By way of example, embodiments of the invention may be described in the context of machine-executable instructions, such as those included in program modules, being executed in devices on target real or virtual processors. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, etc. that perform particular tasks or implement particular abstract data types. In various embodiments, the functionality of the program modules may be combined or divided between program modules as described. Machine-executable instructions for program modules may be executed within local or distributed devices. In a distributed arrangement, program modules may be located in both local and remote memory storage media.

Computer program code for implementing the methods of the present invention may be written in one or more programming languages. These computer program codes may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus, such that the program codes, when executed by the computer or other programmable data processing apparatus, cause the functions/acts specified in the flowchart and/or block diagram block or blocks to be performed. The program code may execute entirely on the computer, partly on the computer, as a stand-alone software package, partly on the computer and partly on a remote computer or entirely on the remote computer or server.

In the context of the present invention, computer program code or related data may be carried by any suitable carrier to enable a device, apparatus or processor to perform various processes and operations described above. Examples of a carrier include a signal, computer readable medium, and the like.

Examples of signals may include electrical, optical, radio, acoustic, or other forms of propagated signals, such as carrier waves, infrared signals, and the like.

A machine-readable medium may be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device. The machine-readable medium may be a machine-readable signal medium or a machine-readable storage medium. A machine-readable medium may include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination thereof. More detailed examples of a machine-readable storage medium include an electrical connection having one or more wires, a portable computer diskette, 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 storage device, a magnetic storage device, or any suitable combination thereof.

Further, while operations are depicted in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In some cases, multitasking or parallel processing may be beneficial. Similarly, while the above discussion contains certain specific implementation details, this should not be construed as limiting the scope of any invention or claims, but rather as a description of specific embodiments that may be directed to a particular invention. Certain features that are described in this specification in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable subcombination.

Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims (8)

1. A path planning method for planning a driving path of a robot on a working site is characterized by comprising the following steps:

acquiring a global map of a work site in two-dimensional representation;

setting an area in the global map, which represents an obstacle and is within a range having a predetermined distance from the periphery of the obstacle, as an avoidance area; and

and taking the geometric center of the robot under the two dimensions as a representative point of the robot, and planning the driving path of the robot in a mode that the representative point of the robot does not enter the avoidance area in the global map.

2. The path planning method according to claim 1,

planning the driving path in a mode that the robot representative point drives to a target area with the shortest distance or the smallest cost from a starting point, wherein the target area is an area which is within a range of a specified radius from a target point and is not the avoidance area.

3. The path planning method according to claim 1 or 2,

the prescribed distance is the longest distance from the geometric center to a point on the outer periphery of the robot.

4. The path planning method according to claim 2,

the robot is a composite robot with a mechanical arm, and the specified radius is the maximum working radius of the mechanical arm.

5. The path planning method according to claim 2,

the global map is a map obtained by arranging a plurality of pixel points according to a two-dimensional matrix, the pixel points of the avoidance area are set as an avoidance point set, the pixel points of the target area are set as a target point set,

the following steps are carried out during path planning:

the first step, adding the starting point into a list to be traversed;

a second step of searching a point with the minimum distance evaluation value from the target point, namely a target point, in the list to be traversed;

a third step of performing breadth-first search on the object point, adding points except traversed points and unreachable points, namely new points, of eight surrounding pixel points to the list to be traversed, removing the object point from the list to be traversed, and setting the object point as a parent node of the new points;

and a fourth step of repeating the second step and the third step, tracing back from the end point to the start point along the parent node when the end point, which is any one point in the target point set, is traversed, and setting a path from the start point to the end point obtained by the tracing back as the travel path, or determining that there is no travel path that can reach the target area when the list to be traversed is empty.

6. A path planning device for planning a travel path of a robot on a work site, comprising:

an acquisition module configured for acquiring a global map of the work site in a two-dimensional representation;

a setting module configured to set, as an avoidance area, an area in the global map that represents an obstacle and is within a range that is a predetermined distance from an outer periphery of the obstacle; and

a planning module configured to plan the travel path of the robot by using the geometric center of the robot in the two dimensions as a robot representative point so that the robot representative point does not enter the avoidance area in the global map.

7. An electronic device is characterized by comprising:

a processor; and

a memory, in which the computer program is stored,

executing the computer program by the processor causes the electronic device to perform the path planning method of any of claims 1-5.

8. A storage medium readable by a computer,

a computer program stored with instructions for causing a computer to perform the method of path planning according to any one of claims 1 to 5.

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