JP7342697B2 - route generation device - Google Patents

Description

The present invention relates to a route generation device.

Conventionally, a route generation device described in Patent Document 1 has been known.
The route generation device includes a map reduction unit that generates a reduced map by reducing the grid map, a general route generation unit that generates a rough route for a moving object based on the reduced map, and a detailed route for a moving object that generates a detailed route based on the rough route. The route generating section includes a detailed route generating section that generates a detailed route.

The map reduction unit generates a reduced map by grouping a plurality of grids of the grid map and averaging the grouped plurality of grids. If the average value of multiple grids is equal to or greater than a critical value, the map reduction unit sets "1", which is information indicating that there is an obstacle, to the averaged grid, and if the average value of multiple grids is equal to or higher than the critical value, If it is less than the value, "0", which is information indicating that there is no obstacle, is set in the averaged grid.

Japanese Patent Application Publication No. 2010-190897

By the way, if information indicating that there are no obstacles when the average value of multiple grids is less than a critical value is set in the averaged grid, the actual position corresponding to the averaged grid will be , there is a possibility that there are obstacles placed to prevent the moving object from moving. Therefore, while the moving object is moving along the route generated by the route generation device, the moving object may become stuck.

The present invention has been made by paying attention to the problems existing in the conventional technology, and an object of the present invention is to provide a route generation device that can generate a route on which a mobile object can move smoothly.

A route generation device that solves the above problems is a route generation device that generates a rough route for a mobile body based on a grid map, and generates a detailed route for the mobile body based on the rough route, the route generation device including: a first process of generating a low-resolution grid map in which the resolution of the grid map is lowered in accordance with the number of grids of the moving object, which is the number of grids that is the minimum width in which the moving object can move, which is set in the grid map; a second process of setting first information that is information indicating that an obstacle is present in a grid in which an obstacle is set among the grids of the low-resolution grid map; and in the low-resolution grid map, the first information is The smallest range of the area formed by a grid that has not been set and at least two grids that are set with the first information that sandwich the grid that is not set with the first information is set as the first grid of the low-resolution grid map. 1 area, and a position corresponding to the first area expressed at the resolution of the grid map is set as a second area of the grid map, and in the second area of the grid map, An obstacle exists at a position corresponding to the first grid where the first information is set and an obstacle exists at a position corresponding to the other grid where the first information is set. a second obstacle that faces the first obstacle grid with a grid located at a position corresponding to a grid where an obstacle is set and where the first information of the first area is not set; The number of grids between the grids is calculated, and if the calculated number of grids is less than the number of moving body grids, the movement is performed to a grid where the first information of the first area is not set. A movement area that is formed by a grid in which second information indicating that the body cannot move, and in which the first information and the second information are not set in the low-resolution grid map, and in which the moving body can move. a third process for distinguishing between an area and a non-moving area that is formed by a grid in which the first information is set and a grid in which the second information is set and is an area in which the moving body cannot move; A fourth process of generating the approximate route between a starting point where the moving body starts moving and a target point of movement of the moving body is performed in the movement area.

According to this, the first information indicating that there is an obstacle is set in the grid in the low-resolution grid map where an obstacle is set, and in the grid in which the moving object cannot move in the low-resolution grid map, the first information is set in the grid in which the obstacle is set. , the second information is set. Therefore, when generating a rough route, it is possible to express a route on which the mobile object cannot travel. Then, in the low-resolution grid map, the movement area in which the mobile object can move becomes clear by the grid in which the first information and the second information are not set. That is, there are no factors on the generated rough route that impede the movement of the mobile object. Since the detailed route is generated based on the general route, it is possible to generate a route on which the mobile object can move smoothly.

In the above route generation device, when the number of mobile object grids is an even number, the grid of the low resolution grid map has a number of grids in the grid map vertically and horizontally equal to the number of mobile object grids divided by "2". It's good if you do.

In the above route generation device, when the number of mobile object grids is an odd number, the grids of the low-resolution grid map are divided by the number obtained by adding "1" to the number of mobile object grids by "2". It is preferable to have grids in the grid map vertically and horizontally.

According to these, in the third process, the first area of the low-resolution grid map is formed by two grids in which two pieces of first information are set in the smallest range and one grid in which no first information is set. be done. Therefore, if the position corresponding to the smallest range of the first area on the grid map is defined as the second area, a plurality of second areas will be formed on the grid map. The route generation device determines, for each of the plurality of second regions, whether the number of grids between obstacles existing in the second region is less than the number of mobile object grids. This is because the route generation device determines whether or not the mobile object can move, compared to the case where the route generation device determines all at once whether the number of grids between obstacles is less than the number of mobile object grids in the entire grid map. Since the number of grids used is small, the processing capacity of the route generation device is reduced. Therefore, the calculation load on the route generation device can be further reduced.

According to this invention, it is possible to generate a route along which a moving object can move smoothly.

Schematic diagram showing an autonomous vehicle. FIG. 3 is a processing flow diagram of the route generation device. The schematic diagram showing the grid map used by a route generation device. The schematic diagram showing the 1st processing of a route generation device. FIG. 6 is a schematic diagram showing second processing of the route generation device. FIG. 7 is a schematic diagram showing a third process of the route generation device. FIG. 7 is a schematic diagram showing a third process of the route generation device. FIG. 7 is a schematic diagram showing a fourth process of the route generation device. FIG. 3 is a schematic diagram showing detailed route generation processing by the route generation device. FIG. 3 is a schematic diagram showing detailed route generation processing by the route generation device. FIG. 3 is a schematic diagram showing detailed route generation processing by the route generation device. FIG. 3 is a schematic diagram showing detailed route generation processing by the route generation device. FIG. 3 is a schematic diagram showing detailed route generation processing by the route generation device.

An embodiment of a route generation device will be described below with reference to FIGS. 1 to 13. Note that the route generation device of this embodiment is applied to an autonomous vehicle such as a transport vehicle that transports a load. Therefore, the route generation device will be explained in the explanation about the autonomous vehicle.

As shown in FIG. 1, the autonomous vehicle 1 includes a route generation device 10 and a vehicle body 20 as a moving object. The route generation device 10 is a control device mounted on the vehicle body 20. The route generation device 10 includes a CPU 11 and a memory 12 including a RAM, a ROM, and the like. The memory 12 stores various programs for controlling the vehicle body 20. The route generation device 10 controls the vehicle body 20 by causing the CPU to execute a program stored in the memory 12.

The route generation device 10 has a function of moving the vehicle body 20 based on map information and the position of the vehicle body 20. Map information is stored in memory 12. The map information includes, for example, information on obstacles in a wide area surrounded by approximately 500 meters on all sides, information on drivable roads on which the vehicle body 20 can travel, and information on impassable roads on which the vehicle body 20 cannot travel. The route generation device 10 may detect the position of the vehicle body 20 using GPS, but may detect objects around the vehicle body 20 using a sensor mounted on the vehicle body 20 such as a distance sensor, and compare the detected objects with map information. It may be estimated. The route generating device 10 generates a route for moving the vehicle body 20 toward a target point G using the detected position of the vehicle body 20 as a starting point S, and moves the vehicle body 20 along the route.

As shown in FIG. 2, the route generation device 10 performs a first process S101, a second process S102, a third process S103, a fourth process S104, and a fifth process when generating a route for the vehicle body 20 to travel. Execute S105. Each process S101, S102, S103, and S104 is a rough route generation process that is a process up to generating the rough route Ro for the vehicle body 20. The fifth process S105 is a process of generating a detailed route Rd for the vehicle body 20 based on the rough route Ro.

As shown in FIG. 3, the route generation device 10 uses a grid map M1 when performing the general route generation process and the detailed route generation process. The grid map M1 is a map expressed by dividing the map information stored in the memory 12 into a grid divided into grids with equally spaced vertical and horizontal lines. Note that the outer frame portion of the grid map M1 indicates a wall of a factory or the like to which the autonomous vehicle 1 is applied. Therefore, in this embodiment, it is assumed that there is an obstacle in the outer frame portion of the grid map M1.

Each process S101, S102, S103, and S104 will be explained according to FIGS. 3 to 8. Note that although FIGS. 4, 5, 7, and 8 show a low-resolution grid map M2, which will be described later, for convenience of explanation, the grid of the grid map M1 is also shown.

As shown in FIG. 4, the first process S101 is a process of generating a low resolution grid map M2 from the grid map M1.
As shown in FIG. 3, when generating the low-resolution grid map M2, the route generation device 10 checks the number of grids corresponding to the width of the vehicle body 20 when the vehicle body 20 is set in the grid map M1. In this embodiment, for example, the number of grids corresponding to the width of the vehicle body 20 is set to "6". The route generation device 10 calculates the minimum width in which the vehicle body 20 can move, which is set in the grid map M1, in consideration of the gap between the vehicle body 20 and the obstacle Ob when the vehicle body 20 can safely move between the obstacles Ob. Check the mobile object grid number N, which is the grid number. The number N of moving object grids in this embodiment is "8". The mobile object grid number N is set to be larger than the grid number corresponding to the width of the vehicle body 20 when the vehicle body 20 is set in the grid map M1. Note that the size of the gap between the vehicle body 20 and the obstacle Ob when the vehicle body 20 can safely move between the obstacles Ob is changed as appropriate depending on the type of the vehicle body 20 and the customer who employs the route generation device 10. . Therefore, the amount of increase from the number of grids corresponding to the width of the vehicle body 20 when the vehicle body 20 is set in the grid map M1 to the number N of grids of the mobile object is changed as appropriate.

As shown in FIG. 4, the route generation device 10 generates a low-resolution grid map M2 by lowering the resolution of the grid map M1 according to the number N of moving object grids in the grid map M1. Since the number N of moving object grids is "8", the low-resolution grid map M2 has a grid having the number of grids in the grid map M1, which is the number N of moving object grids divided by "2", vertically and horizontally. In FIG. 4, the grids separated by thick black lines are the grids of the low-resolution grid map M2.

Here, the reason for using the low resolution grid map M2 in the rough route generation process will be explained.
The larger the size of the map information, the larger the capacity of the memory 12 used to set the map information in the grid map M1. The above map information covers a wide area of 500 meters square, so if the rough route Ro of the vehicle body 20 is generated using the grid map M1, the capacity of the memory 12 to be used is large, so the route generation device 10 The calculation load increases, and the calculation speed of the route generation device 10 also slows down. That is, the reason for using the low-resolution grid map M2 is to reduce the capacity of the memory 12 used to generate the rough route Ro of the vehicle body 20.

The reason for using "2" to divide the number N of mobile object grids is to reduce the capacity of the memory 12 used to generate the rough route Ro. The numerical value divided by the number N of mobile object grids is a numerical value set to lower the resolution of the grid map M1. In order to further reduce the resolution when generating the low-resolution grid map M2 from the grid map M1, it is preferable to make the dividing value as small as possible. Considering that the number of grids is an integer, the value "2" is the maximum value for lowering the resolution of the grid map M1. Therefore, the value "2" is adopted in order to most efficiently reduce the capacity of the memory 12 used to generate the rough route Ro.

In this embodiment, since the number N of moving object grids is an even number, the grid of the low-resolution grid map M2 has the grids of the grid map M1 in the vertical and horizontal directions equal to the number N of moving object grids divided by "2". However, depending on the width of the vehicle body 20, for example, the number N of moving body grids may be an odd number. If the number N of mobile object grids is an odd number, dividing by "2" will not result in an integer. Since the number of grids is generally an integer, if the number N of mobile object grids is an odd number, the grid of the low resolution grid map M2 is the number of mobile object grids N plus "1". The grid map M1 is changed to have the number of grids divided by the number of grids in the vertical and horizontal directions.

As shown in FIG. 5, the second process S102 sets first information I1 that is information indicating that an obstacle Ob is present in a grid to which an obstacle Ob is set among the grids of the low-resolution grid map M2. It is processing. In FIG. 5, the first information I1 is set in the grid of the low resolution grid map M2 provided with diagonal lines. In this embodiment, the numerical value "1" is adopted as the first information I1. That is, when an obstacle Ob is set in at least one of the plurality of grids of the grid map M1 included in one grid of the low-resolution grid map M2, the obstacle Ob is set in the entire area of the one grid of the low-resolution grid map M2. It is treated as if there is an obstacle Ob. Note that the first information I1 does not have to be a numerical value of "1", and may be, for example, a numerical value of "0". Further, the first information I1 is not limited to numerical values, but may be characters. That is, as long as the first information I1 is set in the grid of the low-resolution grid map M2 as information indicating that there is an obstacle Ob, the setting contents may be changed as appropriate.

Next, the third process S103 will be explained according to FIGS. 5 to 7. The third process S103 is a process for distinguishing between a moving area Ma, which is an area in which the vehicle body 20 can move, and a non-moving area Mun, which is an area in which the vehicle body 20 cannot move.

As shown in FIG. 5, the low-resolution grid map M2 is formed by a grid in which the first information I1 is not set, and a grid in which the first information I1 is set, sandwiching the grid in which the first information I1 is not set. It has a plurality of first regions R1. In this embodiment, the first region R1 is configured of one grid in which the first information I1 is not set and two grids in which the first information I1 is set in the low resolution grid map M2. In other words, the smallest range of the area formed by the grid in which the first information I1 is not set and the grid in which the first information I1 is set sandwiching the grid in which the first information I1 is not set is defined as the first area. It is set as R1. In the third process S103, it is determined whether there is a sufficient number of grids for the vehicle body 20 to move in the first region R1. Specifically, this will be explained using FIG. 6.

FIG. 6 illustrates one of the plurality of first regions R1. In the third process S103, the first region R1 of the low-resolution grid map M2 is compared with the second region R2 of the grid map M1 indicating a position corresponding to the first region R1. Specifically, only the position corresponding to the first region R1 of the low-resolution grid map M2 is expressed with the resolution of the grid map M1, and the placement of the obstacle Ob is confirmed in detail. In the third process S103, it is determined whether the number of grids between obstacles Ob existing in the second region R2 of the grid map M1 is less than the number N of moving object grids. For example, in FIG. 6, the number of grids between obstacles Ob is "6". Therefore, in the first region R1 shown in FIG. 6, it can be confirmed that the obstacles Ob are arranged so that the vehicle body 20 cannot move.

As shown in FIG. 7, in the third process S103, if the number of grids between obstacles Ob existing in the second region R2 of the grid map M1 is less than the number N of moving object grids, the first information I1 of the first region R1 Second information I2 indicating that the vehicle body 20 cannot move to a grid where is not set is set. The second information I2 is set in the grid of the low-resolution grid map M2, which has diagonal lines added compared to FIG. 5 . In this embodiment, a numerical value of "0" is adopted as the second information I2. In the third process S103, the above process is performed for each of the plurality of first regions R1 of the low resolution grid map M2. As a result, in the third process S103, the movement area Ma formed by the grid in which the first information I1 and the second information I2 are not set in the low resolution grid map M2, and the first information I1 or the second information I2 are set. A non-moving area Mun formed by the grid is distinguished from the non-moving area Mun. Note that the second information I2 does not have to be a numerical value of "0", and may be, for example, a numerical value of "1". In this case, it is preferable to use "0" as the first information I1. Further, the second information I2 is not limited to numerical values, and may be characters. That is, as long as the second information I2 is set in the grid of the low-resolution grid map M2 as information indicating that the vehicle body 20 cannot move, the setting contents may be changed as appropriate.

As shown in FIG. 8, in the fourth process S104, in the movement area Ma of the low resolution grid map M2, a starting point S where the vehicle body 20 starts moving and a target point G which is the target point of the movement of the vehicle body 20 are determined. A rough route Ro is generated between them. The route generation device 10 can employ various route generation methods, but in this embodiment, for example, the A-Star search algorithm or Dijkstra algorithm is used to generate the shortest rough route Ro from the starting point S to the target point G. is being generated. Note that the generated general route Ro does not need to be the shortest route from the starting point S to the target point G, and if there is a via point that the autonomous vehicle 1 should pass through, it can be routed from the starting point S to the relevant point in the movement area Ma. A rough route Ro reaching the target point G via way points may be generated. Further, the algorithm used when generating the rough route Ro from the starting point S to the target point G may be changed as appropriate.

Next, the fifth process S105 will be explained according to FIGS. 9 to 13.
As shown in FIG. 9, in the fifth process S105, in the low-resolution grid map M2, the first divided area Sd1, the second divided area Sd2, and the second divided area Sd2 including the peripheral portion of the rough route Ro generated in the rough route generation process are Divide into three divided regions Sd3. The above-mentioned peripheral portion refers to a portion including a part of the obstacle Ob existing in the vicinity of the approximate route Ro. The first divided region Sd1 includes a starting point S on the rough route Ro. The third divided region Sd3 includes the target point G on the approximate route Ro. The second divided area Sd2 is an area between the first divided area Sd1 and the third divided area Sd3. The second divided region Sd2 is arranged so as to partially overlap the first divided region Sd1 and the third divided region Sd3.

As shown in FIG. 10, in the fifth process S105, an area of the grid map M1 corresponding to the first divided area Sd1 of the low-resolution grid map M2 is confirmed, and a first detailed route Rd1 for moving the vehicle body 20 is generated. do.

As shown in FIG. 11, in the fifth process S105, an area of the grid map M1 corresponding to the second divided area Sd2 of the low-resolution grid map M2 is confirmed, and a second detailed route Rd2 for moving the vehicle body 20 is generated. do. At this time, the second divided region Sd2 includes the end point of the first detailed route Rd1 in the first divided region Sd1. In the fifth process S105, a second detailed route Rd2 is generated using the end point of the first detailed route Rd1 as the starting point of the second detailed route Rd2.

As shown in FIG. 12, in the fifth process S105, an area of the grid map M1 corresponding to the third divided area Sd3 of the low-resolution grid map M2 is confirmed, and a third detailed route Rd3 for moving the vehicle body 20 is generated. do. The third divided region Sd3 includes the end point of the second detailed route Rd2 in the second divided region Sd2. In the fifth process S105, a third detailed route Rd3 is generated using the end point of the second detailed route Rd2 as the starting point of the third detailed route Rd3. That is, as shown in FIG. 9, the reason why the second divided region Sd2 partially overlaps with the first divided region Sd1 and the third divided region Sd3 is because the routes Rd1, Rd2, and Rd3 are continuously configured. It's for a reason.

As shown in FIG. 13, in the fifth process S105, a detailed route Rd is generated by making the routes Rd1, Rd2, and Rd3 generated in each of the divided regions Sd1, Sd2, and Sd3 consecutive on the grid map M1. That is, the route generation device 10 generates a rough route Ro for the vehicle body 20 based on the grid map M1, and generates a detailed route Rd for the vehicle body 20 based on the rough route Ro. Note that in this embodiment, the low-resolution grid map M2 is divided into divided regions Sd1, Sd2, and Sd3, but the present invention is not limited to this. For example, it may be divided into two, or may be divided into four or more. The smaller the number of divisions into which the low-resolution grid map M2 is divided, the greater the number of grids in the grid map M1 to represent, and therefore the capacity of the memory 12 used to generate each route Rd1, Rd2, Rd3 increases. Therefore, the capacity of the memory 12 used to generate each route Rd1, Rd2, and Rd3 of the route generation device 10 increases, and the calculation speed of the route generation device 10 becomes slow. Therefore, the number of divisions into which the low-resolution grid map M2 is divided is changed as appropriate depending on the capacity of the memory 12 of the route generation device 10.

The operation of this embodiment will be explained.
The first information I1 is set in the grid of the low-resolution grid map M2 where the obstacle Ob is set, and the second information I2 is set in the grid in which the vehicle body 20 cannot move in the low-resolution grid map M2. ing. Therefore, when generating the rough route Ro, a route on which the vehicle body 20 cannot move is expressed. Then, in the low-resolution grid map M2, the movement area Ma in which the vehicle body 20 can move becomes clear by the grid in which the first information I1 and the second information I2 are not set. That is, there are no factors that hinder the movement of the vehicle body 20 on the generated rough route Ro.

The effects of this embodiment will be explained.
(1) Since there are no factors that impede the movement of the vehicle body 20 on the generated general route Ro and the detailed route Rd is generated based on the general route Ro, a route on which the vehicle body 20 can move smoothly can be generated.

(2) In the third process S103, the first region R1 of the low-resolution grid map M2 is formed by two grids in which first information is set and one grid in which no first information is set. Therefore, if a position corresponding to the first region R1 on the grid map M1 is defined as a second region R2, a plurality of second regions R2 are formed on the grid map M1. The route generation device 10 determines whether or not the number of grids between the obstacles Ob existing in the second region R2 is less than the number N of mobile object grids for each of the plurality of second regions R2. This determines whether the vehicle body 20 can move or not, compared to the case where the route generation device 10 determines all at once whether the number of grids between obstacles Ob is less than the number N of moving object grids in the entire grid map M1. Since the number of grids used to determine the number of grids is small, the processing capacity of the route generation device 10 is reduced. Therefore, the calculation load on the route generation device 10 can be further reduced.

Note that this embodiment can be implemented with the following modifications. This embodiment and the following modified examples can be implemented in combination with each other within a technically consistent range.
In the low-resolution grid map M2, the first region R1 may include a grid in which two pieces of first information I1 are set and a grid in which a plurality of pieces of first information I1 are not set.

In the present embodiment, the outer frame portion of the grid map M1 represents a wall of a factory or the like, so it is treated as an obstacle Ob, but the present invention is not limited to this. When generating a route along which the vehicle body 20 moves based on the grid map M1, there is a starting point S and a target point G on the grid map M1. Therefore, since a route for the vehicle body 20 to leave the grid map M1 is not generated in the first place, the outer frame portion of the grid map M1 may be set as an area in which the vehicle body 20 cannot move. That is, the second information I2 indicating that the vehicle body 20 cannot be moved may be set in the outer frame portion of the low resolution grid map M2. When changing in this way, in the low-resolution grid map M2, one grid in which the first information I1 is not set and a grid in which the first information I1 is set sandwiching the grid in which the first information I1 is not set. and a grid in which the second information I2 is set. The route generation device 10 determines whether the number of grids in the grid map M1 at the position corresponding to the third area is less than the number N of moving body grids, and if it is less than the number N of moving body grids, the route generation device 10 Second information I2 is set in a grid where information I1 is not set. Therefore, the moving area Ma and the non-moving area Mun can be distinguished in the low resolution grid map M2.

○ Although the autonomous vehicle 1 is a transport vehicle, it is not limited to this. For example, it may be a mobile robot such as a cleaning robot.
Although the route generation device 10 was applied to the autonomous vehicle 1, it may also be applied to a vehicle such as a car or a forklift. Furthermore, although the route generation device 10 has generated a route along which the vehicle body 20 as a moving body moves, for example, when an avatar in a computer-generated space is used as a moving body, a route along which the avatar moves in a computer-generated space. may be generated.

10... Route generation device, 20... Vehicle body, Ro... General route, Rd... Detailed route, M1... Grid map, M2... Low resolution grid map, S101... First process, S102... Second process, S103... Third process, S104...Fourth process, I1...First information, I2...Second information, R1...First area, R2...Second area, Ma...Movement area, Mun...Non-movement area, S...Start point, G...Target point , Ob...obstacle, N...number of moving object grids.

Claims (3)

A route generation device that generates a rough route for a moving body based on a grid map, and generates a detailed route for the mobile body based on the rough route,
The route generation device includes:
a first process of generating a low-resolution grid map in which the resolution of the grid map is lowered in accordance with the number of moving object grids, which is the number of grids with a minimum width through which the moving object can pass, which is set in the grid map;
a second process of setting first information that is information indicating that an obstacle is present in a grid in which an obstacle is set among the grids of the low-resolution grid map;
The smallest range of the area formed by the grid in which the first information is not set and at least two grids in which the first information is set sandwiching the grid in which the first information is not set is determined by the A resolution grid map is set as a first area, and a position corresponding to the first area expressed at the resolution of the grid map is set as a second area of the grid map, and the second area of the grid map is set as a second area of the grid map. In the area, a first obstacle grid in which an obstacle is set that exists at a position corresponding to one grid in which the first information is set corresponds to the other grid in which the first information is set. facing the first obstacle grid with a grid located at a position corresponding to a grid set with an obstacle located at a position where the first information of the first area is not set. the number of grids between the second obstacle grid and the second obstacle grid , and if the calculated number of grids is less than the number of moving object grids, the first information of the first area is set. second information indicating that the mobile object cannot move is set in a grid that does not have the first information and the second information set in the low-resolution grid map, and the mobile object moves while the first information and the second information are not set in the low-resolution grid map. a moving area that is an area in which the moving body can move; and a non-moving area that is an area that is formed by a grid in which the first information is set and a grid in which the second information is set and in which the moving object cannot move. 3 processing and
A fourth process of generating the approximate route between a starting point where the moving body starts moving and a target point of movement of the moving body in the moving area. Device. When the number of moving object grids is an even number, the grid of the low-resolution grid map has a number of grids in the grid map vertically and horizontally equal to the number of moving object grids divided by "2". The route generation device according to claim 1. When the number of mobile object grids is an odd number, the grids of the low-resolution grid map are formed by dividing the number of grids in the grid map by adding "1" to the number of mobile object grids by "2" vertically and horizontally. 3. The route generation device according to claim 1, further comprising: