Method, medium, and apparatus for self-propelled mobile unit with obstacle avoidance during wall-following algorithm

• US 7,885,738 B2
• Filed: 11/22/2005
• Issued: 02/08/2011
• Est. Priority Date: 11/26/2004
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Won, Jong-chan, Kim, Jay-woo, Park, Jun-ho
• Primary Examiner(s): Hellner; Mark
• Assistant Examiner(s): Algahaim; Helal A
• Application Number:
  US11/283,831
• Publication Number:
  US 20060229774A1
• Time in Patent Office: 1,904 Days
• Field of Search: 701/23, 701/26, 701/301, 700/245, 318/568.2
• US Class Current: 701/23
• 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 1/0255 using acoustic signals, e.g. ultra-sonic singals sonar systems designed for anti-collision purposes G01S15/93

Abstract

A method, medium, and apparatus of a self-propelled mobile unit with obstacle avoidance during wall-following. In the self-propelled mobile unit, a carrying unit may move the mobile unit by using a transmitted power, and a sensor unit can detect an obstacle and a wall, which may be respectively placed in front of and to the side of the mobile unit, with respect to a moving direction of the carrying unit. A controller may direct the carrying unit by generating a path along which the carrying unit moves according to a detection result from the sensor unit. Accordingly, the controller can direct the carrying unit to move while maintaining a predetermined distance (within a predetermined range) from the wall. If the sensor unit detects an obstacle, the controller directs the carrying unit to move in an obstacle free direction.

Claims

1. A self-propelled mobile unit, comprising:

a carrying unit to move the mobile unit;

a sensor unit to detect an obstacle in front of the mobile unit and a wall to a side of the mobile unit, both with respect to a direction of motion of the carrying unit; and

a controller to control the carrying unit movement of the mobile unit by generating a path along which the carrying unit is controlled to move, according to a detection result of the sensor unit,

wherein the controller directs the carrying unit to move the mobile unit while controlling a distance between the mobile unit and the wall, and

wherein the controller directs the carrying unit to move the mobile unit in a direction free of obstacles if the sensor unit detects an obstacle,

wherein the sensor unit comprises an obstacle sensor unit to detect the obstacle in front of the mobile unit, a wall sensor unit to detect the wall, an upward sensor unit to detect the obstacle, existing upward with respect to the direction of motion of the carrying unit and a sensor signal processor to process signals from the obstacle sensor unit, the wall sensor unit, and the upward sensor unit, the signals including information about the detected obstacle,

wherein, when the obstacle sensor unit does not detect the obstacle in front of the mobile unit while the upward sensor unit detects the obstacle in front of the mobile unit, the controller directs the carrying unit to move in a direction different from the direction of motion of the carrying unit corresponding to the detected obstacle if a height of the obstacle detected by the upward sensor unit is determined to be less than a height of the mobile unit.

2. The self-propelled mobile unit of claim 1, wherein the controller directs the carrying unit to move the mobile unit while controlling the distance to be within a predetermined range.

3. The self-propelled mobile unit of claim 1, further comprising an operation executing unit to perform at least one of a humidifying operation, an air cleaning operation, and a vacuum cleaning operation.

4. The self-propelled mobile unit of claim 1, wherein the sensor unit further comprises a collision sensor unit to detect a collision of the mobile unit with the obstacle, and

wherein the controller directs the carrying unit to move the mobile unit in a direction different from the direction of motion of the carrying unit corresponding to the detected obstacle if the collision is detected by the collision sensor unit.

5. The self-propelled mobile unit of claim 1, wherein the sensor unit further comprises a crash sensor unit to detect an unevenness of a surface, upon which the carrying unit travels, in front of the mobile unit with respect to the direction of motion of the carrying unit, and

the controller directs the carrying unit to move the mobile unit in a direction different from the direction of motion of the carrying unit corresponding to the detected obstacle, with the detected obstacle being the unevenness of the surface.

6. The self-propelled mobile unit of claim 1, wherein the controller comprises:

an obstacle avoidance unit to generate a direction and a distance that the mobile unit is controlled to move to avoid the obstacle;

a wall-following unit to generate a direction and a distance that the carrying unit is controlled to move to maintain a predetermined distance from the wall; and

a path generator to respectively combine the direction and distance generated by the obstacle avoidance unit and the direction and distance generated by the wall-following unit to generate a control signal to control movement of the carrying unit.

7. The self-propelled mobile unit of claim 6, wherein the controller further comprises an exception processor to generate a direction of motion and distance for finding a wall when the sensor unit does not detect the wall,

wherein the path generator produces a control signal to control movement of the carrying unit corresponding to the generated direction of motion and distance for finding the wall.

8. The self-propelled mobile unit of claim 1, wherein the controller controls the carrying unit or the sensor unit to rotate when the obstacle is detected by the sensor unit;

the sensor unit scans for obstacles within a predetermined range from a position after the rotation of the carrying unit or sensor unit; and

the controller directs the carrying unit to move in a direction corresponding to the position after the rotation of the carrying unit or sensor when no obstacles are detected by the scan for obstacles.

9. The self-propelled mobile unit of claim 1, wherein the carrying unit comprises:

a driving unit driven by power transmitted from a power source to control the moving direction of the mobile unit;

a traveling unit driven by a driving force transmitted from the driving unit to move the mobile unit in the moving direction controlled by the driving unit; and

a distance calculating unit to calculate a distance traveled by the traveling unit.

10. The self-propelled mobile unit of claim 9, wherein the driving unit comprises:

a steering unit to control the moving direction; and

a power transmission unit to receive the driving force from the power source.

18. The self-propelled mobile unit of claim 1, wherein the sensor unit further comprises a window frame sensor unit to detect a window existing in front of or to a side of the mobile unit, with respect to the direction of motion of the carrying unit, and wherein the controller uses a detected position of a detected window to decide if the detected window should be considered an obstacle or a wall, and directs movement of the carrying unit accordingly.

11. A method of self-propelling a mobile unit with obstacle avoidance during wall-following, the method comprising:

detecting for a wall near the mobile unit;

approaching the detected wall;

moving the mobile unit in a first moving direction while maintaining the mobile unit at a distance from the wall, within a predetermined range;

scanning for an obstacle in the first moving direction;

turning the mobile unit in a first turning direction if the obstacle is detected; and

moving the mobile unit in the first turning direction if the first turning direction is obstacle free,

wherein the scanning for the obstacle comprises scanning in a direction of motion of the mobile unit and scanning in an upward direction with respect to the direction of motion, and determining whether a height of the obstacle is less than a height of the mobile unit when the obstacle is detected in the scanned upward direction while not being detected in the scanned direction of motion.

12. The method of claim 11, wherein the moving of the mobile unit in the obstacle free direction comprises:

turning the mobile unit in a second turning direction; and

scanning for obstacles within a predetermined range in the second turning direction.

13. The method of claim 11, wherein detecting of the obstacle existing in the first moving direction comprises detecting a window, as the obstacle.

14. The method of claim 11, further comprising moving the mobile unit a predetermined distance and scanning for the wall again if the wall is not detected.

15. The method of claim 11, further comprising repeating the scanning for the wall and the approaching of the wall after moving the mobile unit in the first turning direction.

16. The method of claim 11, further comprising repeating the approaching of the wall, after moving the mobile unit in the first turning direction, based on a determination of a position of the repeated approached wall being based on a known direction of movement of the mobile unit and calculating a distance moved in the first turning direction.

17. At least one medium comprising computer readable code to implement the method of claim 11.

19. The method of claim 11, wherein the detecting of the obstacle existing in the path of the mobile unit comprises detecting a window existing in the first moving direction of the mobile unit.