Method and apparatus for reckoning position of moving robot

• US 20070118248A1
• Filed: 10/17/2006
• Published: 05/24/2007
• Est. Priority Date: 11/23/2005
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Choi, Ki-wan, Myeong, Hyeon, Lee, Hyoung-ki, Bang, Seok-won, Lee, Yong-beom
• Granted Patent: US 9,058,039 B2
• Time in Patent Office: Days
• US Class Current: 700/245
• CPC Class Codes: G05D 1/0225 involving docking at a fixed facility, e.g. base station or loading bay parking aids B62D15/027
• 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 1/0246 using a video camera in combination with image processing means
• CPC Class Codes: G05D 1/027 comprising intertial navigation means, e.g. azimuth detector inertial navigation G01C21/16; inertial navigation combined with non-inertial navigation instruments G01C21/165
• CPC Class Codes: G05D 1/0272 comprising means for registering the travel distance, e.g. revolutions of wheels measuring distance traversed on the ground by vehicles, e.g. using odometers G01C22/00
• CPC Class Codes: G05D 1/028 using a RF signal

Abstract

A method and apparatus for reckoning a position of a moving robot using dead-reckoning and range sensing. The method includes performing dead-reckoning to determine a variation state in accordance with motion of the moving robot, calculating an absolute position of the moving robot by sensing a distance between the moving robot and at least one fixed position, predicting an optimized current position of the moving robot using the variation state and the absolute position, determining whether the optimized current position is within a specified effective area, and correcting the optimized current position in accordance with the determined result.

Claims

1. A method of reckoning a position of a moving robot, comprising:

performing dead-reckoning to determine a variation state in accordance with motion of the moving robot;

sensing a distance between the moving robot and at least one fixed position to calculate an absolute position of the moving robot; and

predicting an optimized current position of the moving robot using the variation state and the absolute position.

2. The method of claim 1, wherein the performing is executed by an encoder and/or a gyroscope.

3. The method of claim 1, wherein the at least one fixed position is in a charge station of the moving robot.

4. The method of claim 1, wherein the at least one fixed position includes a fixed position in a charge station and another fixed position.

5. The method of claim 3, wherein the sensing is executed by transmission and reception of a radio wave between a transceiver in the moving robot and respective transceivers at the at least fixed position.

6. The method of claim 4, wherein the sensing is executed by transmission and reception of a radio wave between a transceiver in the moving robot and respective transceivers at the at least fixed position.

7. The method of claim 5, wherein the radio wave is a ultra wide band (UWB) signal.

8. The method of claim 1, wherein the predicting comprises calculating a current state value through a Kalman filter using the variation state and the absolute position.

9. The method of claim 1, wherein the predicting comprises calculating a current state value through a Kalman filter using the variation state, the absolute position and position information sensed by an auxiliary sensor.

10. The method of claim 9, wherein the auxiliary sensor comprises at least one of a nearby obstacle sensor, a laser sensor, a distance sensor, and a camera.

11. The method of claim 9, further comprising obtaining a feature point of the moving robot using the nearby obstacle sensor as the auxiliary sensor, wherein the position information sensed by the auxiliary sensor includes x and y coordinate values of the feature point.

12. A method of reckoning a position of a moving robot, comprising:

predicting an absolute position of the moving robot using at least one sensor;

determining whether the predicted absolute position is within an effective area calculated from a signal received from at least one fixed transceiver; and

performing relocation in which the absolute position is reset, when the predicted absolute position is not within the effective area.

13. The method of claim 12, wherein the effective area is an area of overlap when a circle is drawn by reflecting an error band E₁ in a radius r₁ around a first transceiver at a first position of at least two fixed positions and another circle is drawn by reflecting an error band E₂ in a radius r₂ around a second transceiver at a second position of the at least two fixed positions, and

wherein radius r₁ represents a distance between the moving robot and the first transceiver and radius r₂ represents a distance between the moving robot and the second transceiver.

14. The method of claim 13, wherein the effective area simultaneously satisfies the following equations:

(r₁−

μ

)≦

x(k)²+(y(k)+ W/2)²≦

(r₁+μ

)²
(r₂−

μ

)≦

x(k)²+(y(k)+ W/2)²≦

(r₂+μ

)², and

wherein μ

represents E₁/2, x(k) represents an X-axis directional position of the moving robot in a state of k, y(k) represents a Y-axis directional position in a state of k, and W represents a distance between the first transceiver and the second transceiver.

15. The method of claim 12, wherein the effective area is an area of a circle drawn by reflecting an error band E in a radius r around one fixed transceiver, and

wherein radius r represents the distance between the moving robot and the transceiver.

16. The method of claim 15, wherein the effective area satisfies the following equation:

(r−

μ

)²≦

x(k)²+y(k)²≦

(r+μ

)², and

wherein μ

represents E₁/2, x(k) represents an X-axis directional position of the moving robot in a state of k, and y(k) represents a Y-axis directional position in a state of k.

17. The method of claim 12, wherein the performing relocation comprises obtaining a current position of the moving robot using a separate auxiliary sensor.

18. The method of claim 17, wherein the auxiliary sensor comprises at least one of a nearby obstacle sensor, a laser sensor, a distance sensor, and a camera.

19. A method of reckoning a position of a moving robot, comprising:

performing dead-reckoning to determine a variation state in accordance with motion of the moving robot;

calculating an absolute position of the moving robot by sensing a distance between the moving robot and at least one fixed position;

predicting an optimized current position of the moving robot using the variation state and the absolute position;

determining whether the optimized current position is within a specified effective area; and

correcting the optimized current position in accordance with a result of the determining.

20. An apparatus for reckoning a position of a moving robot, comprising:

a dead-reckoning section determining a variation state in accordance with motion of the moving robot;

a distance calculator calculating an absolute position of the moving robot by sensing a distance between the moving robot and at least one fixed position; and

a state predictor predicting an optimized current position of the moving robot using the variation state and the absolute position as input values of a Kalman filter.

21. The apparatus of claim 20, wherein the dead-reckoning section comprises an encoder and/or a gyroscope.

22. The apparatus of claim 20, wherein the at least one fixed position is at a charge station of the moving robot.

23. The apparatus of claim 20, wherein the at least one fixed position is a fixed position at a charge station and another fixed position.

24. The apparatus of claim 22, wherein the distance calculator performs transmission and reception of a radio wave between a transceiver in the moving robot and respective transceivers at the at least fixed position.

25. The apparatus of claim 23, wherein the distance calculator performs transmission and reception of a radio wave between a transceiver in the moving robot and respective transceivers at the at least fixed position.

26. The apparatus of claim 20, wherein the state predictor calculates a current state value through a Kalman filter using the variation state and the absolute position.

27. The apparatus of claim 20, wherein the state predictor calculates a current state value through a Kalman filter using the variation state, the calculated absolute position and position information sensed by an auxiliary sensor.

28. An apparatus of reckoning a position of a moving robot, comprising:

a predictor predicting an absolute position of the moving robot using at least one sensor;

relocation determining unit determining whether the absolute position is within an effective area calculated from a signal received from at least one fixed transceiver; and

a relocation unit performing relocation in which the absolute position is reset, when the predicted absolute position is not within the effective area.

29. The apparatus of claim 28, wherein the effective area is an area of overlap when a circle is drawn by reflecting an error band E₁ in a radius r₁ around a first transceiver at a first position of at least two fixed positions and another circle is drawn by reflecting an error band E₂ in a radius r₂ around a second transceiver at a second position of the at least two fixed positions, and

wherein radius r₁ represents a distance between the moving robot and the first transceiver and radius r₂ represents a distance between the moving robot and the second transceiver.

30. The apparatus of claim 28, wherein the effective area is an area of a circle drawn by reflecting an error band E in a radius r around one fixed transceiver, and

wherein radius r represents a distance between the moving robot and the transceiver.

31. The apparatus of claim 28, wherein the relocation unit obtains a current position of the moving robot using a separate auxiliary sensor.

32. The apparatus of claim 31, wherein the auxiliary sensor comprises at least one of a nearby obstacle sensor, a laser sensor, a distance sensor, and a camera.

33. An apparatus of reckoning a position of a moving robot, comprising:

a dead-reckoning section performing dead-reckoning to determine a variation state in accordance with motion of the moving robot;

a distance calculator calculating an absolute position of the moving robot by sensing a distance between the moving robot and at least one fixed position;

a state predictor predicting an optimized current position of the moving robot using the variation state and the absolute position;

a relocation determining unit determining whether the optimized current position is within a specified effective area; and

a relocation unit correcting the optimized current position in accordance with a result of the determining.