Mapping method, localization method, robot system, and robot

1. A mapping method of a mobile robot that conducts mapping using at least one or a plurality of an environmental sensor node, the mapping method comprising:

acquiring first map information created in advance, including information about a surrounding area of the mobile robot;

acquiring second map information including information about the surrounding area of the mobile robot by an external sensor onboard the mobile robot;

receiving third map information including information about the surrounding area of the mobile robot from the environmental sensor node;

(i) in the third map information, if information exists about a place in which an amount of change over time is equal to or greater than a certain threshold value,

conducting a removal process of removing information about a place in the first map information and information about a place in the second map information that correspond to the place in which the amount of change over time is equal to or greater than the certain threshold value in the third map information, or alternatively,

conducting a variance-increasing process of increasing a variance of each of information about a place in the first map information and information about a place in the second map information that correspond to the place in which the amount of change over time is equal to or greater than the certain threshold value in the third map information;

(ii) matching the first map information and the second map information after being subjected to the removal process or the variance-increasing process, and generating map information based on the matching result; and

(iii) updating the first map information to the map information generated based on the matching result.

2. The mapping method according to claim 1 , wherein

in the third map information, if information exists about a place in which the amount of change over time between a first timing and a second timing is equal to or greater than the certain threshold value,

the removal process is conducted if a time difference between the first timing and the second timing is within a range between a first time and a second time longer than the first time, and

the variance-increasing process is conducted if the time difference between the first timing and the second timing is equal to or greater than the second time.

3. The mapping method according to claim 2 , wherein

in the third map information, if information exists about a place in which the amount of change over time between the first timing and the second timing is equal to or greater than the certain threshold value,

if the time difference between the first timing and the second timing is less than or equal to the first time, the removal process and the variance-increasing process are not conducted, the first map information and the second map information are matched, and map information is generated based on the matching result.

4. The mapping method according to claim 1 , wherein

in the third map information, if information does not exist about a place in which the amount of change over time is equal to or greater than the certain threshold value, the first map information and the second map information are matched, and map information is generated based on the matching result.

5. The mapping method according to claim 1 , wherein

the variance-increasing process is a process of increasing an indefiniteness of information about a corresponding place in the first map information and a corresponding place in the second map information.

6. The mapping method according to claim 1 , wherein

the third map information includes information about an existence probability of an object near the environmental sensor node, and

the amount of change over time is an amount of change in the existence probability.

7. The mapping method according to claim 1 , wherein

the first map information, the second map information, and the third map information are coordinate information in a two-dimensional coordinate system or coordinate information in a three-dimensional coordinate system, and

before conducting the matching, a coordinate conversion process is conducted to convert the respective coordinate systems of the first map information, the second map information, and the third map information to a common coordinate system.

8. A localization method of a mobile robot that conducts localization using at least one sensor node, the localization method comprising:

acquiring first map information created in advance, including information about a surrounding area of the mobile robot;

acquiring second map information including information about the surrounding area of the mobile robot by an external sensor onboard the mobile robot;

receiving third map information including information about the surrounding area of the mobile robot from an environmental sensor node;

(i) in the third map information, if information exists about a place in which an amount of change over time is equal to or greater than a certain threshold value,

conducting a removal process of removing information about a place in the first map information and information about a place in the second map information that correspond to the place in which the amount of change over time is equal to or greater than the certain threshold value in the third map information, or alternatively,

conducting a variance-increasing process of increasing a variance of each of information about a place in the first map information and information about a place in the second map information that correspond to the place in which the amount of change over time is equal to or greater than the certain threshold value in the third map information;

(ii) matching the first map information and the second map information after being subjected to the removal process or the variance-increasing process, and generating map information based on the matching result;

(iii) updating the first map information to the map information generated based on the matching result; and

(iv) estimating a location of the mobile robot in the updated first map information, based on the updated first map information, and a detection result of an internal sensor that detects at least one of a position and an orientation of the mobile robot.

9. The localization method according to claim 8 , further comprising:

calculating a movement path based on the updated first map information and the estimated location; and

causing the mobile robot along the movement path.

10. A robot system comprising:

at least one environmental sensor node; and

a mobile robot, wherein

the environmental sensor node acquires third map information including information about a surrounding area of the mobile robot,

the mobile robot includes

a database recording first map information created in advance, including information about a surrounding area of the mobile robot,

an external sensor that acquires second map information including information about the surrounding area of the mobile robot,

a communicator that communicates with the environmental sensor node to acquire the third map information, and

an information processor that

(i) in the third map information, if information exists about a place in which an amount of change over time is equal to or greater than a certain threshold value,

conducts a removal process of removing information about a place in the first map information and information about a place in the second map information that correspond to the place in which the amount of change over time is equal to or greater than the certain threshold value in the third map information, or alternatively,

conducts a variance-increasing process of increasing a variance of each of information about a place in the first map information and information about a place in the second map information that correspond to the place in which the amount of change over time is equal to or greater than the certain threshold value in the third map information,

(ii) matches the first map information and the second map information after being subjected to the removal process or the variance-increasing process, and generates map information based on the matching result, and

(iii) updates the first map information recorded in advance to the map information generated based on the matching result.

11. A mobile robot, comprising:

a database recording first map information created in advance, including information about a surrounding area of the mobile robot;

an external sensor that acquires second map information including information about the surrounding area of the mobile robot;

a communicator that acquires third map information including information about the surrounding area of the mobile robot by communicating with at least one environmental sensor node, which is external to the mobile robot and which acquires the third map information; and

an information processor that

(i) in the third map information, if information exists about a place in which an amount of change over time is equal to or greater than a certain threshold value,

conducts a removal process of removing information about a place in the first map information and information about a place in the second map information that correspond to the place in which the amount of change over time is equal to or greater than the certain threshold value in the third map information, or alternatively,

conducts a variance-increasing process of increasing a variance of each of information about a place in the first map information and information about a place in the second map information that correspond to the place in which the amount of change over time is equal to or greater than the certain threshold value in the third map information,

(ii) matches the first map information and the second map information after being subjected to the removal process or the variance-increasing process, and generates map information based on the matching result, and

(iii) updates the first map information recorded in advance to the map information generated based on the matching result.