AUTONOMOUS MOBILE ROBOT, SELF POSITION ESTIMATION METHOD, ENVIRONMENTAL MAP GENERATION METHOD, ENVIRONMENTAL MAP GENERATION APPARATUS, AND DATA STRUCTURE FOR ENVIRONMENTAL MAP

• US 20110010033A1
• Filed: 01/26/2009
• Published: 01/13/2011
• Est. Priority Date: 02/26/2008
• Status: Active Grant

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Mima, Kazuhiro, Yabushita, Hidenori, Asahara, Yoshiaki
• Granted Patent: US 9,239,580 B2
• Time in Patent Office: Days
• US Class Current: 701/26
• CPC Class Codes: G05D 1/0231 using optical position detecting means position-fixing by using electromagnetic waves other than radio waves, e.g. optical position detecting means G01S5/16
• CPC Class Codes: G05D 1/024 in combination with a laser lasers per se H01S
• CPC Class Codes: G05D 1/0242 using non-visible light signals, e.g. IR or UV signals
• CPC Class Codes: G05D 1/0251 extracting 3D information from a plurality of images taken from different locations, e.g. stereo vision stereoscopic image analysis H04N13/00; depth recovery from images G06T7/593
• CPC Class Codes: G05D 1/0255 using acoustic signals, e.g. ultra-sonic singals sonar systems designed for anti-collision purposes G01S15/93
• CPC Class Codes: G05D 1/0274 using mapping information stored in a memory device navigation using map-matching G01C21/30

Abstract

To improve the accuracy of the self position estimation of a mobile robot. A robot measures a distance to an object in the mobile environment by using a range sensor. An environmental map storage unit stores an environmental map containing a plurality of map data each corresponding to a respective one of a plurality of measurement directions from which a point in the mobile environment is to be observed. A self position estimation unit selects a map data corresponding to a measurement direction in which a distance to the object is measured by the range sensor from the plurality of map data. Then, the self position estimation unit estimates a self position of the mobile robot based on the selected map data and range data obtained by the range sensor.

Claims

1. A mobile robot comprising:

a range sensor that measures a distance to an object in a mobile environment;

an environmental map storage unit that stores an environmental map containing a plurality of map data, each of the plurality of map data corresponding to a respective one of plurality of measurement directions from which a point in the mobile environment is to be observed; and

a self position estimation unit that selects a map data corresponding to a measurement direction in which the object is measured by the range sensor from the plurality of map data, and estimates a self position of the mobile robot based on the selected map data and range information of the object obtained by the range sensor.

2. The mobile robot according to claim 1, wherein angler interval of the measurement directions for classifying the map data is set to be larger than resolution of a measurement angle of the range sensor.

3. The mobile robot according to claim 1, wherein:

the range sensor is a laser range finder that obtains range information of a plurality of measured points by scanning with a laser beam; and

the self position estimation unit classifies each of the plurality of measured points into one of the plurality of the measurement directions based on a radiating direction of the laser beam and a candidate self position calculated by using odometry, and estimates the self position by comparing the range information of each of the plurality of measured points with the map data corresponding to the classified measurement direction.

4. The mobile robot according to claim 1, wherein the map data includes at least one of information indicating whether or not the mobile robot can move through the point, information indicating a distance from the point to a nearest obstacle, and information indicating a height of the point.

5. A method of estimating a self position of a mobile robot that moves in mobile environment, the method comprising:

measuring a distance to an object in the mobile environment;

referring to an environmental map containing a plurality of map data, each of the plurality of map data corresponding to a respective one of plurality of measurement directions from which a point in the mobile environment is to be observed;

selecting a map data corresponding to a measurement direction in which range measurement for the object is carried out from the plurality of map data; and

estimating a self position of the mobile robot based on the selected map data and range information of the object.

6. The method of estimating a self position according to claim 5, wherein angular interval of the measurement directions for classifying the map data is set to be larger than resolution of a measurement angle of the range sensor.

7. A method of generating an environmental map in regard to mobile environment of a mobile robot, the method comprising:

measuring a point in the mobile environment from a plurality of measurement directions;

generating a plurality of map data in regard to the point, each of the plurality of map data being generated for a respective one of the plurality of measurement directions based on a measurement result for the respective one of the plurality of measurement directions; and

associating coordinate information to specify a position of the point with the plurality of map data and storing them.

8. An apparatus that generates an environmental map in regard to mobile environment of a mobile robot, comprising:

a device that receives measurement results of a point in the mobile environment, the measurement results being obtained by measuring the point from a plurality of measurement directions;

a device that generates a plurality of map data in regard to the point, each of the plurality of map data being generated for a respective one of the plurality of measurement directions based on a measurement result for the respective one of the plurality of measurement directions; and

a device that associates coordinate information to specify a position of the point with the plurality of map data and stores them.

9. A data structure for an environmental map comprising:

coordinate information to specify a position of a mobile robot in mobile environment; and

map data of a point observed from a first measurement direction, and map data of the point observed from a second measurement direction different from the first measurement direction, the point being specified by the coordinate information.

10. The data structure of an environmental map according to claim 9, wherein the map data includes at least one of information indicating whether or not the mobile robot can move through the point, information indicating a distance from the point to a nearest obstacle, and information indicating a height of the point.