KR101807370B1

KR101807370B1 - Method and device for planning path of mobile robot

Info

Publication number: KR101807370B1
Application number: KR1020150179707A
Authority: KR
Inventors: 서일홍; 김용년; 고동욱
Original assignee: 한양대학교 산학협력단
Priority date: 2015-12-16
Filing date: 2015-12-16
Publication date: 2018-01-18
Also published as: KR20170071712A

Abstract

Disclosed is a method and an apparatus for randomly generating a vector using the reliability that the mobile robot does not collide with an obstacle and planning a traveling path of the mobile robot using a randomly generated vector. The disclosed travel path planning method comprises: determining a first maximum magnitude for a parent vector, according to a probability of collision with an obstacle at a first location; Randomly generating a plurality of parent vectors starting from the first position within the first maximum size range; Determining a second maximum size for a child vector according to a probability of collision with the obstacle in a second position that is an endpoint of a selected first parent vector of the parent vectors; Determining a second parent vector in which an end point exists outside an area in which the second maximum size child vector can be reached using the child vector in the second position as the starting point and in the direction of the end point of the parent vectors; ; And determining the first parent vector and the second parent vector as a traveling path.

Description

TECHNICAL FIELD [0001] The present invention relates to a method and an apparatus for planning a traveling path of a mobile robot,

The present invention relates to a method and apparatus for planning a traveling path of a mobile robot, and more particularly, to a method and apparatus for planning a traveling path of a mobile robot by randomly generating a vector using reliability that the mobile robot does not collide with an obstacle, And a method and apparatus for planning a traveling route.

The most basic function of a mobile robot is to travel to a desired target point. In the event of an accident that can not be accessed by a person, the mobile robot moves to an accident site on behalf of a person and performs work such as site confirmation and lifesaving. These functions are performed by a localization technique and a mapping technique of a mobile robot.

On the other hand, the mobile robot plans the traveling route and travels by using the planned traveling route. A related prior art is Korean Patent Publication No. 2013-010913.

Methods for planning and generating existing paths require coordination between the path generation rate and the quality of the path, depending on the environment. Random sampling based path planning methods generate paths at a high speed, but in order to maximize the quality of the path, the number of sampling times suited to the environment should be determined. For example, a lot of sampling is necessary in a narrow and complicated driving environment, and less sampling is required in a wide driving environment.

A robot designed to travel in a narrow area and a robot designed to travel in a large area can travel effectively in conflicting areas only through separate tuning. Moreover, in the environment including the narrow path, the random sampling-based path generation methods have a problem that even if a very large number of sampling is performed, the solution can not be found, and even if a solution is found, the amount of computation increases due to very large sampling.

The present invention is to provide a method and apparatus for randomly generating a vector using the reliability that the mobile robot does not collide with an obstacle and planning a traveling path of the mobile robot using a randomly generated vector.

Another object of the present invention is to provide a method and apparatus for efficiently planning a traveling path of a mobile robot according to reliability regardless of a driving environment.

According to an aspect of the present invention, there is provided a traveling path planning method for a mobile robot, the method comprising: determining a first maximum size for a parent vector according to a collision probability with an obstacle at a first location; ; Randomly generating a plurality of parent vectors starting from the first position within the first maximum size range; Determining a second maximum size for a child vector according to a probability of collision with the obstacle in a second position that is an endpoint of a selected first parent vector of the parent vectors; Determining a second parent vector in which an end point exists outside an area in which the second maximum size child vector can be reached using the child vector in the second position as the starting point and in the direction of the end point of the parent vectors; ; And determining the first parent vector and the second parent vector as a travel route in accordance with the determination result.

According to another aspect of the present invention, there is provided a traveling path planning method for a mobile robot, the method comprising: calculating a distance between a first position and a first obstacle, Randomly generating a plurality of vectors; Determining an outer vector having an end point outside a region whose center is the end point position of the selected representative vector among the vectors and the distance between the end point position and the second obstacle is a radius among the plurality of vectors; And determining the representative vector and the external vector as a travel route in accordance with the determination result.

According to another aspect of the present invention, there is provided an apparatus for planning a traveling path of a mobile robot, the apparatus comprising: a first maximum size for a parent vector in accordance with a probability of collision with an obstacle at a first position; A vector size determiner; A vector generating unit for randomly generating a plurality of parent vectors within the first maximum size range; A second position that is an end point of the selected first parent vector among the parent vectors is used as a starting point and a child vector that is directed toward the end point direction of the parent vectors is used to determine an end point A vector determination unit for determining an existing second parent vector; And a travel path determining unit that determines the first parent vector and the second parent vector as a travel route in accordance with a result of the determination, A traveling path planning apparatus for determining the second maximum size is provided.

According to the present invention, it is possible to generate a traveling route more quickly by using a large-size vector in a region where the obstacle does not collide with a high degree of reliability. In a region with low reliability that does not collide with an obstacle, It is possible to plan the traveling route.

Further, according to the present invention, it is possible to prevent the number of vectors generated for generating the traveling route from being continuously increased, and the amount of computation can be reduced.

1 is a view for explaining a traveling path planning apparatus of a mobile robot according to an embodiment of the present invention.
2 is a view for explaining a traveling path calculating method of a mobile robot according to an embodiment of the present invention.
Figure 3 is a diagram showing a parent vector at a first location;
4 is a diagram showing a parent vector and a child vector for a parent vector.
FIG. 5 is a diagram showing a parent vector determined by a traveling route. FIG.
6 is a diagram showing a parent vector and a child vector to be regenerated.
7 is a view showing an extended travel route.
8 is a view showing a traveling route using the traveling route planning method according to the present invention.
9 is a view for explaining a traveling route planning method according to another embodiment of the present invention.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. Like reference numerals are used for like elements in describing each drawing.

The traveling path planning method of the mobile robot according to the present invention uses a randomly sampled vector. By the selected vector among the randomly generated vectors, the traveling route from the starting point to the target point is determined.

At this time, the present invention randomly generates a vector based on the reliability that will not collide with the obstacle at the starting point, and the maximum size of the vector or the sampling resolution of the vector can be determined according to the reliability. The reliability that does not collide with the obstacle can be determined in consideration of the distance between the mobile robot and the obstacle, the speed of the mobile robot, and the like.

For example, a high confidence that no collision with an obstacle will result in a relatively large vector and a low sampling resolution for the vector. Or a low confidence that it will not collide with an obstacle will result in a relatively small vector and a high sampling resolution for the vector.

Therefore, according to the present invention, it is possible to generate a traveling route more quickly by using a large-size vector in an area where reliability does not collide with an obstacle, and to use a smaller size vector in a low- It is possible to precisely generate the traveling route. Each vector can represent a linear path of the mobile robot.

Further, the present invention introduces the concept of a parent vector and a child vector, and selects a representative vector representing a traveling path from the parent vector using the child vector for the parent vector. The child vector is a vector pointing to the end point of a selected one of the parent vectors and to the end point of the remaining parent vectors. Therefore, according to the present invention, since the rest of the vectors other than the representative vector are excluded from the traveling path planning object, the number of vectors generated for generating the traveling path can be prevented from continuously increasing, and the amount of computation can be reduced.

Meanwhile, the mobile robot according to the present invention includes various types of movable robots such as a robot cleaner, an unmanned vehicle, and a service robot.

Hereinafter, embodiments according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a view for explaining a traveling path planning apparatus of a mobile robot according to an embodiment of the present invention.

1, the travel path planning apparatus according to the present invention includes a vector size determination unit 110, a vector generation unit 120, a vector determination unit 130, and a travel path determination unit 140. [

The vector size determination unit 110 determines the first maximum size for the parent vector according to the reliability at which the first location does not collide with the obstacle. That is, the vector size determination unit 110 determines the first maximum size according to the collision probability with the obstacle. The collision probability with the obstacle can be changed according to the distance between the first position and the obstacle, the speed of the mobile robot, etc. In one embodiment, the collision probability with the obstacle can be expressed as a distance from the obstacle. The greater the distance between the first position and the obstacle, the greater the reliability of the collision with the obstacle and the first maximum magnitude can also increase.

The first position is a starting position of the mobile robot, and may be an end point of a parent vector determined by a traveling path described later.

The vector size determination unit 110 determines a second maximum size for the child vector according to the collision probability with the obstacle at the second position, which is the end point of the first parent vector.

The vector generating unit 120 randomly generates a plurality of parent vectors within the first maximum size range. The parent vector is a vector starting from the first position, and is a vector centered on the first position and not exceeding the region having the first maximum size as a radius. That is, the size of the parent vector is less than the first maximum size, and a parent vector having the same size as the first maximum size and a parent vector smaller than the first maximum size can be generated.

At this time, the first maximum size is determined according to the collision probability with the obstacle. The first maximum size may increase as the collision probability with the obstacle is smaller, that is, the reliability that the collision with the obstacle is greater. Also, the number of randomly generated parent vectors, that is, the random sampling resolution, can be determined according to the collision probability with the obstacle, and the smaller the probability of collision with the obstacle, the smaller the number of randomly generated parent vectors.

The vector determination unit 130 determines a second maximum position of the first vector by using the second position that is the end point of the selected first parent vector among the parent vectors, A second parent vector in which an end point exists outside of the second parent vector. In order to select a parent vector that is not represented by the representative vector among the parent vectors, the first vector is a representative vector, and the vector determining unit 130 selects a region of the second vector having a radius of the second maximum size A second parent vector having an end point outside is determined from a plurality of parent vectors. In this case, it is preferable that the first parent vector is selected from the first maximum-size parent vector.

If all the end points of the parent vector are included in a region having a radius of the second maximum size, all the parent vectors can be represented by child vectors starting from the first position. Thus, a plurality of parent vectors may be represented by a first parent vector. However, the second parent vector whose end point is located outside the region having the radius of the second maximum size among the parent vectors can not be represented by the child vector whose starting point is the first position, and therefore, It should be determined as a driving route.

As a result, the traveling path determining unit 140 determines the first parent vector and the second parent vector as the traveling path according to the determination result of the vector determining unit 130. If the second parent vector does not exist, the travel path determining unit 140 determines the first parent vector as the traveling path. When there are a plurality of second parent vectors whose end points are located outside the region having the radius of the second maximum size among the parent vectors, the travel path determining unit 140 may determine all of the plurality of second parent vectors as the travel paths .

Thereafter, the traveling path planning apparatus according to the present invention can generate the traveling path by repeating the above-described process, with the end point of the parent vector determined as the traveling path as the first position. The traveling route planning apparatus according to the present invention selects one of the parent vectors that can be represented by the child vector as a representative vector (first parent vector), thereby preventing a sudden increase in the random vector even if the above- have.

FIG. 2 is a view for explaining a traveling route planning method of a mobile robot according to an embodiment of the present invention, and will be described with reference to FIGS. 3 to 8. FIG. FIG. 3 is a diagram showing a parent vector at a first position, and FIG. 4 is a diagram showing a parent vector and a child vector for a parent vector. FIG. 5 is a diagram showing a parent vector determined by a traveling path, and FIG. 6 is a diagram showing a parent vector and a child vector to be regenerated. 7 is a view showing an extended travel route.

The traveling path planning method according to the present invention can be performed in a mobile robot or a separate traveling path planning apparatus. In FIG. 2, a traveling path planning method of the traveling path planning apparatus in FIG. 1 is described as an embodiment.

The traveling path planning apparatus according to the present invention determines a first maximum size for a parent vector according to a collision probability with an obstacle in a first position 310, The first maximum size can be determined according to the collision probability between the first position 310 and the closest obstacle. And the first maximum magnitude may be expressed as the distance d from the first position 310 to the obstacle 320 as shown in Figure 3 and may be expressed as a distance d from the first position 310 to the obstacle 320, Can be determined in proportion to the distance.

The traveling route planning apparatus randomly generates a plurality of parent vectors having the first position 310 as the starting point within the first maximum size range (S220). That is, as shown in FIG. 3, the travel path planning apparatus generates a parent vector that does not deviate from the region 330 having the first maximum size as a radius centered on the first position 310. The number of the plurality of parent vectors may be determined according to the collision probability, and a parent vector having a size smaller than the first maximum size or equal to the first maximum size is randomly generated.

The travel path planning device determines a second maximum size for the child vector according to the probability of collision with the obstacle at the second position 410, which is the end point of the selected first parent vector 340 among the plurality of parent vectors (S230) . As with the first maximum size, the second maximum size may be determined according to the probability of collision between the second location 410 and the closest obstacle, among the peripheral obstacles in the second location 410. And the distance from the second location 410 to the obstacle 320 and may be determined in proportion to the distance to the obstacle 320. [ The obstacle 320 of FIG. 4 is the same as the obstacle 320 of FIG. 3, but according to the embodiment, the travel path planning device can determine the second maximum size according to the probability of collision with a new obstacle.

The traveling path planning apparatus selects the first parent vector 340 from the first maximum size parent vector 340, 350, 360, and 370, and uses the child vector determined according to the first parent vector 340, And determines a second parent vector 350 having an end point in a region outside the second maximum size about the second position 410 (S240). That is, as shown in FIG. 4, the travel path planning apparatus includes a second parent vector (FIG. 4) in which an end point exists in an area outside the region 420 having the second maximum size as a radius, 350) among a plurality of parent vectors.

For example, the traveling path planning apparatus generates a plurality of child vectors for a plurality of parent vectors, starting from the second position 410, to generate child vectors. As shown in Fig. 4, the child vector (dotted line vector) is a vector in which the parent vector (solid line vector) is the end point, and the end point of the child vector is the end point of the parent vector.

Since the end point of the parent vector excluding the second parent vector 350 is included in the region 420 having the second maximum size as the radius, the parent vector excluding the second parent vector 350 is included in the first parent vector 340 And the first parent vector 340 becomes a representative vector of the parent vector except for the second parent vector 350. [ And the child vector 430 for the second parent vector 350 leaves the region 420 with the second maximum magnitude as a radius and thus the second parent vector 350 is represented as the first parent vector 340 Can not be.

Finally, the travel route planning device determines the first parent vector 340 and the second parent vector 350 as the travel route (S250) according to the determination result, and the determined travel route can be shown as in FIG. When the second parent vector 350 does not exist, that is, when the first parent vector 340 represents all the parent vectors, the traveling path planning device determines the first parent vector 340 as the traveling path.

By repeating the above-described steps, the traveling route can be expanded. The traveling path planning apparatus has a plurality of parent vectors starting from the first position, with the end points of the first and second parent vectors 340 and 350 determined in FIG. 5 as the first positions, as shown in FIG. 6 Randomly generates a child vector for the selected parent vector 610, 620. If a predetermined parent vector is selected using the child vector, the traveling path can be finally expanded as shown in FIG.

At this time, according to the embodiment, the travel path planning apparatus can select the first parent vector with all of the generated parent vectors as candidates. For example, as well as the parent vectors 610 and 620, the parent vectors 340 and 350 may also be selected as the first parent vector.

6 and 7, since the child vector starting at the end point 650 of the selected parent vector 620 may reach the end point of the other parent vector 640, 650, the parent vector 620 may be the second parent 630, and 640 randomly generated with the end point of the vector 350 as a first position. That is, the end points of the parent vectors 620, 630, and 640 are all included in the radius of the distance between the end point 650 of the selected parent vector 620 and the obstacle 320.

8 is a view showing a traveling route using the traveling route planning method according to the present invention.

8 (a) and 8 (b) show a traveling path of a mobile robot generated in an environment where different obstacles exist. The green line represents a parent vector determined by the traveling route, and can be generated by the traveling route planning method described above. The red line indicates the finally determined travel route according to the set origin and destination.

As shown in FIG. 8, according to the present invention, a traveling route that does not collide with an obstacle can be planned, and an optimal traveling route can be selected according to a starting location and a destination.

9 is a view for explaining a traveling route planning method according to another embodiment of the present invention.

The traveling route planning apparatus according to the present invention randomly generates a plurality of vectors having a size smaller than a distance between the first position and the first obstacle and having a first position as a starting point (S910). The plurality of vectors may correspond to the parent vector described above, and the first obstacle may be the obstacle closest to the first position among the obstacles around the first position. The first position may be a start position of the mobile robot or an end point of a representative vector and an outer vector determined by a traveling path described later.

The traveling route planning apparatus judges an external vector having an end point outside the region whose center is the end point position of the selected representative vector among the plurality of vectors and the distance between the end point position and the second obstacle is a radius, )do. The representative vector may correspond to the first parent vector described above, and the outer vector may correspond to the second parent vector described above. And the second obstacle is the obstacle closest to the second position among the obstacles around the second position, and may be the same as or different from the first obstacle.

The traveling route planning apparatus determines the representative vector and the external vector as the traveling route in accordance with the determination result (S930), and repeats the steps S910 and S920 to generate the traveling route. As an example, the traveling path planning apparatus may randomly generate a plurality of vectors with the representative point and the end point of the outer vector as the first positions, and determine the representative vector and the outer vector.

The above-described technical features may be implemented in the form of program instructions that can be executed through various computer means and recorded in a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, and the like, alone or in combination. The program instructions recorded on the medium may be those specially designed and constructed for the embodiments or may be available to those skilled in the art of computer software. Examples of computer-readable media include magnetic media such as hard disks, floppy disks and magnetic tape; optical media such as CD-ROMs and DVDs; magnetic media such as floppy disks; Magneto-optical media, and hardware devices specifically configured to store and execute program instructions such as ROM, RAM, flash memory, and the like. Examples of program instructions include machine language code such as those produced by a compiler, as well as high-level language code that can be executed by a computer using an interpreter or the like. The hardware device may be configured to operate as one or more software modules to perform the operations of the embodiments, and vice versa.

As described above, the present invention has been described with reference to particular embodiments, such as specific elements, and specific embodiments and drawings. However, it should be understood that the present invention is not limited to the above- And various modifications and changes may be made thereto by those skilled in the art to which the present invention pertains. Accordingly, the spirit of the present invention should not be construed as being limited to the embodiments described, and all of the equivalents or equivalents of the claims, as well as the following claims, belong to the scope of the present invention .

Claims

A traveling route planning method for a mobile robot,
Determining a first maximum magnitude for a parent vector according to a probability of collision with an obstacle at a first location;
Randomly generating a plurality of parent vectors starting from the first position within the first maximum size range;
Determining a second maximum size for a child vector according to a probability of collision with the obstacle in a second position that is an endpoint of the selected first parent vector of the parent vectors;
Determining a second parent vector in which an end point exists outside an area in which the second maximum size child vector can be reached using the child vector in the second position as the starting point and in the direction of the end point of the parent vectors; ; And
Determining the first parent vector and the second parent vector as a traveling path according to the determination result
Wherein the traveling route planning method comprises:

The method according to claim 1,
The number of the plurality of parent vectors is
Is determined according to the collision probability
How to plan a driving route.

The method according to claim 1,
The first and second maximum sizes are
Is determined in proportion to the distance from the first and second positions to the obstacle
How to plan a driving route.

The method of claim 3,
Wherein determining the first maximum size comprises:
Determining the first maximum size according to a collision probability between the first position and the closest obstacle among the peripheral obstacles in the first position,
Wherein determining the second maximum size comprises:
Determining the second maximum size according to a collision probability between the second position and the closest obstacle among the peripheral obstacles in the second position
How to plan a driving route.

The method according to claim 1,
The first parent vector
The first largest-sized parent vector is selected as a parent vector
How to plan a driving route.

The method according to claim 1,
The step of determining the second parent vector
Generating a plurality of child vectors for the plurality of parent vectors with the second position as a starting point; And
Determining a second parent vector for the child vector out of the second maximum size of the child vectors,
The end point of the child vector is an end point of the parent vector
How to plan a driving route.

A traveling route planning method for a mobile robot,
Randomly generating a plurality of vectors starting from the first position with a size smaller than a distance between the first position and the first obstacle;
An outer vector having an end point outside a region having a radius as a center between a second position that is an end point position of the selected representative vector and a distance between the second position and the second obstacle is determined from the plurality of vectors step; And
Determining the representative vector and the outer vector as a traveling path according to the determination result
Wherein the traveling route planning method comprises:

8. The method of claim 7,
Wherein the first obstacle is an obstacle closest to the first position,
Wherein the second obstacle is an obstacle closest to the second position
How to plan a driving route.

8. The method of claim 7,
The first position
The start position of the mobile robot or the end point of the representative vector and the outer vector
How to plan a driving route.

A travel route planning apparatus for a mobile robot,
A vector magnitude determination unit for determining a first maximum magnitude for a parent vector according to a probability of collision with an obstacle in a first position;
A vector generating unit for randomly generating a plurality of parent vectors within the first maximum size range;
A second position that is an end point of the selected first parent vector among the parent vectors is used as a starting point and a child vector that is directed toward the end point direction of the parent vectors is used to determine an end point A vector determination unit for determining an existing second parent vector; And
And a traveling path determining unit for determining the first parent vector and the second parent vector as a traveling path according to the determination result,
Wherein the vector size determination unit determines the second maximum size according to a probability of collision with the obstacle in the second position
Driving path planning device.