Autonomous mobile body and control method of same

• US 8,948,956 B2
• Filed: 11/10/2010
• Issued: 02/03/2015
• Est. Priority Date: 11/20/2009
• Status: Active Grant

• Current Assignee: Murata Machinery Limited (Muratec)
• Original Assignee: Murata Machinery Limited (Muratec)
• Inventors: Takahashi, Masaki, Suzuki, Takafumi, Moriguchi, Toshiki
• Primary Examiner(s): Tarcza, Thomas
• Assistant Examiner(s): Dunn, Alex C
• Application Number:
  US13/510,396
• Publication Number:
  US 20130131910A1
• Time in Patent Office: 1,546 Days
• Field of Search: 701/27
• US Class Current: 701/27
• CPC Class Codes: B25J 13/00 Controls for manipulators programme controls B25J9/16; control in general G05
• CPC Class Codes: B25J 5/00 Manipulators mounted on wheels or on carriages B25J1/00 takes precedence; programme-controlled manipulators B25J9/00 ; vehicle aspects B60, B62, e.g. remote-controlled steering for motor vehicles B62D1/24; control of position of vehicles G05D1/00
• CPC Class Codes: B25J 5/007 mounted on wheels
• CPC Class Codes: G05D 1/021 specially adapted to land vehicles
• CPC Class Codes: G05D 1/0212 with means for defining a desired trajectory involving a plurality of land vehicles G05D1/0287
• CPC Class Codes: G05D 1/0238 using obstacle or wall sensors G05D1/0246 and G05D1/0289 take precedence; lidar systems designed for anti-collision purposes G01S17/93
• CPC Class Codes: G05D 1/024 in combination with a laser lasers per se H01S
• CPC Class Codes: Y10S 901/01 Mobile robot

Abstract

An autonomous mobile body is configured to flexibly avoid obstacles. The mobile body has a movement mechanism configured to translate in a horizontal plane and rotate around a vertical axis, and the distance to an obstacle is derived for each directional angle using an obstacle sensor. A translational potential of the mobile body and a rotational potential of the mobile body for avoiding interference with the obstacle are generated, based on the distance from the autonomous mobile body to the obstacle at each directional angle. An amount of control relating to a translational direction and a translational velocity of the mobile body and an amount of control relating to a rotational direction and an angular velocity of the mobile body are generated based on the generated potentials, and the movement mechanism is driven.

Claims

1. An autonomous mobile body configured to avoid an obstacle and move autonomously to a goal, comprising:

a platform vehicle having a movement mechanism configured to translate in a horizontal plane and rotate around a vertical axis;

an obstacle sensor for deriving a distance to an obstacle for each directional angle;

a potential generator for generating a translational potential of the mobile body and a rotational potential of the mobile body for avoiding interference with the obstacle, based on the distance from the autonomous mobile body to the obstacle at each directional angle;

a control amount generator for generating an amount of control relating to a translational direction and a translational velocity of the mobile body and an amount of control relating to a rotational direction and an angular velocity of the mobile body, based on the generated potentials;

a drive controller for combining the generated amounts of control and driving the movement mechanism; and

wherein the autonomous mobile body is processed as a body with anisotropy and said body includes a major axis and a minor axis.

2. The autonomous mobile body according to claim 1, the potentials being potential membership functions according to a fuzzy potential method, the translational potential membership function representing a degree of interference with the obstacle at each translational direction angle, and the rotational potential membership function representing a degree of interference with the obstacle at each rotational direction angle.

3. The autonomous mobile body according to claim 2, the control amount generator deciding a translational velocity between a highest translational velocity and a lowest translational velocity, and deciding an angular velocity between a highest angular velocity and a lowest angular velocity, based on values of the potential membership functions.

4. The autonomous mobile body according to claim 2, the potential generator generating translational and rotational potential membership functions for each of a plurality of obstacles, generating translational and rotational potential membership functions for guiding the autonomous mobile body to a destination, and combining the potential membership functions for the obstacles with the potential membership functions for the destination respectively for translation and rotation.

5. The autonomous mobile body according to claim 4, the combining of translational potential membership functions involves deriving, for each directional angle, a highest value or a lowest value from a result of combining the plurality of translational potential membership functions, and the combining of rotational potential membership functions involves deriving, for each directional angle, a highest value or a lowest value from a result of combining the plurality of rotational potential membership functions.

6. The autonomous mobile body according to claim 1, the control amount generator deriving the amount of translational control and the amount of rotational control independently.

7. The autonomous mobile body according to claim 1, the movement mechanism having three or more drive wheels each provided, on a perimeter thereof, with a roller configured to rotate in a direction parallel to a wheel axis, and the three or more drive wheels including a drive wheel having a different wheel axis direction.

9. The autonomous mobile body according to claim 3, the potential generator generating translational and rotational potential membership functions for each of a plurality of obstacles, generating translational and rotational potential membership functions for guiding the autonomous mobile body to a destination, and combining the potential membership functions for the obstacles with the potential membership functions for the destination respectively for translation and rotation.

10. The autonomous mobile body according to claim 2, the control amount generator deriving the amount of translational control and the amount of rotational control independently.

11. The autonomous mobile body according to claim 3, the control amount generator deriving the amount of translational control and the amount of rotational control independently.

12. The autonomous mobile body according to claim 4, the control amount generator deriving the amount of translational control and the amount of rotational control independently.

13. The autonomous mobile body according to claim 5, the control amount generator deriving the amount of translational control and the amount of rotational control independently.

8. A method of controlling movement of an autonomous mobile body configured to avoid an obstacle and move autonomously to a goal, the mobile body having a movement mechanism configured to translate in a horizontal plane and rotate around a vertical axis, the method causing the mobile body to perform the steps of:

deriving a distance from the autonomous mobile body to an obstacle for each directional angle using an obstacle sensor;

processing the autonomous mobile body with anisotropy;

generating a translational potential of the mobile body and a rotational potential of the mobile body for avoiding interference with the obstacle, based on the distance from the autonomous mobile body to the obstacle at each directional angle;

generating an amount of control relating to a translational direction and a translational velocity of the mobile body and an amount of control relating to a rotational direction and an angular velocity of the mobile body, based on the generated potentials; and

combining the generated amounts of control and driving the movement mechanism.

14. An autonomous mobile body configured to avoid an obstacle and move autonomously to a goal, comprising:

a platform vehicle having a movement mechanism configured to translate in a horizontal plane and rotate around a vertical axis;

one or more extendible arms projecting from the mobile body;

which result in a non-uniform shape temporally based on arms projections and retractions while in use;

an obstacle sensor for deriving a distance to an obstacle for each directional angle;

a potential generator for generating a translational potential of the mobile body and a rotational potential of the mobile body for avoiding interference with the obstacle, based on the distance from the autonomous mobile body to the obstacle at each directional angle;

a control amount generator for generating an amount of control relating to a translational direction and a translational velocity of the mobile body and an amount of control relating to a rotational direction and an angular velocity of the mobile body, based on the generated potentials;

a drive controller for combining the generated amounts of control and driving the movement mechanism;

wherein the autonomous mobile body is processed as a body with anisotropy and said body includes a major axis and a minor axis;

wherein the potentials are potential membership functions according to a fuzzy potential method, the translational potential membership function representing a degree of interference with the obstacle at each translational direction angle, and the rotational potential membership function representing a degree of interference with the obstacle at each rotational direction angle;

wherein the control amount generator decides a translational velocity between a highest translational velocity and a lowest translational velocity, and decides an angular velocity between a highest angular velocity and a lowest angular velocity, based on values of the potential membership functions.

15. The autonomous mobile body according to claim 14, the movement mechanism having three or more drive wheels each provided, on a perimeter thereof, with a roller configured to rotate in a direction parallel to a wheel axis, and the three or more drive wheels including a drive wheel having a different wheel axis direction.

16. The autonomous mobile body according to claim 14, the potential generator generating translational and rotational potential membership functions for each of a plurality of obstacles, generating translational and rotational potential membership functions for guiding the autonomous mobile body to a destination, and combining the potential membership functions for the obstacles with the potential membership functions for the destination respectively for translation and rotation.

17. The autonomous mobile body according to claim 14, the control amount generator deriving the amount of translational control and the amount of rotational control independently.