Position sensing device for mobile robots and robot cleaner equipped with the same

• US 20060237634A1
• Filed: 12/30/2005
• Published: 10/26/2006
• Est. Priority Date: 04/23/2005
• Status: Abandoned Application

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Kim, Sang Yun
• Application Number:
  US11/320,771
• Publication Number:
  US 20060237634A1
• Time in Patent Office: Days
• US Class Current: 250/221
• CPC Class Codes: G01S 17/48 Active triangulation systems, i.e. using the transmission and reflection of electromagnetic waves other than radio waves
• CPC Class Codes: G01S 7/495 Counter-measures or counter-counter-measures using electronic or electro-optical means

Abstract

A position sensing device for mobile robots comprises a light-receiving element configured such that light is focused on different positions of the light-receiving element according to the distance from an obstruction, a light-emitting element to emit the light, which is reflected by the obstruction and is incident on the light-receiving element, in a straight line, the light-emitting element serving to emit the light at a predetermined angle to the external jamming light such that an imaginary obstruction formed by an external jamming light incident on the light-receiving element is positioned out of an effective sensing range, a signal processing unit to calculate the distance from the obstruction based on the position where the light incident on the light-receiving element is focused, and an incorrect signal processing unit to determine whether the obstruction is present within the distance considering the change of the distance sensed by the position sensing device while the mobile robot is driven. Consequently, the mobile robot is properly operated although the external jamming light is present, and incorrect recognition of the distance from the obstruction due to reflection of the light, which is emitted while being inclined, not by the obstruction but by a floor of a moving space is prevented.

Claims

1. A position sensing device for mobile robots, comprising:

a light-receiving element configured such that light is focused on different positions of the light-receiving element according to the distance from an obstruction, from which the light is reflected;

a light-emitting element configured to emit the light, which is reflected by the obstruction and is incident on the light-receiving element, in a straight line, the light-emitting element serving to emit the light at a predetermined angle to the external jamming light such that an imaginary obstruction formed by an external jamming light incident on the light-receiving element is positioned out of an effective sensing range, within which the mobile robot is driven, among a sensible range of the distance from the obstruction; and

a signal processing unit configured to calculate the distance from the obstruction based on the position where the light incident on the light-receiving element is focused.

2. The position sensing device as set forth in claim 1, further comprising:

an incorrect signal processing unit configured to determine whether the obstruction is present within the distance considering the change of the distance sensed by the position sensing device while the mobile robot is driven.

3. The position sensing device as set forth in claim 1, wherein the light-emitting element comprises:

an infrared light-emitting diode for emitting infrared light; and

a light-transmitting lens for condensing the infrared light emitted from the infrared light-emitting diode such that the infrared light emitted from the infrared light-emitting diode is advanced in a straight line.

4. The position sensing device as set forth in claim 1, wherein the light-receiving element comprises:

a light-receiving lens for condensing the light reflected by the obstruction; and

a position-sensitive detector configured such that the light condensed by the light-receiving lens is focused on the position-sensitive detector.

5. The position sensing device as set forth in claim 1, wherein the light-emitting element is configured to emit the light at a predetermined angle, at which the degree of deviation in position of the imaginary obstruction sensed by the light-receiving element out of the effective sensing range is greater than the minimum unit distance distinguishable according to the accuracy of the signal processing unit.

6. The position sensing device as set forth in claim 1, wherein the light-emitting element is configured to emit the light at a predetermined angle, at which the light emitted from the light-emitting element is directed to a floor of a moving space, which is the maximum distance of the effective sensing range.

7. A robot cleaner comprising:

at least one position sensing device for emitting light to a floor of a cleaning space at a predetermined angle to the floor of the cleaning space such that the light emitted from the at least one position sensing device is distinguished from an external jamming light to sense the distance from an obstruction, from which the light is reflected; and

an information processing unit for transmitting a signal to the at least one position sensing device and receiving a signal from the at least one position sensing device to control a drive unit such that the robot cleaner cleans the cleaning space while the robot is driven in the cleaning space.

8. The robot cleaner as set forth in claim 7, further comprising:

a case forming the contour of a main body;

a cleaning unit mounted at the main body for cleaning the cleaning space; and

a drive unit for driving the main body such that the main body is moved on the floor of the cleaning space while supporting the main body.

9. The robot cleaner as set forth in claim 7, wherein the at least one position sensing device comprises:

a light-emitting element configured to emit light in a straight line;

a light-receiving element configured such that the light is focused on different positions of the light-receiving element according to the distance from the obstruction, from which the light is reflected; and

a signal processing unit configured to calculate the distance from the obstruction based on the position where the light incident on the light-receiving element is focused.

10. The robot cleaner as set forth in claim 9, wherein the light-emitting element comprises:

an infrared light-emitting diode for emitting infrared light; and

a light-transmitting lens for condensing the infrared light emitted from the infrared light-emitting diode such that the infrared light emitted from the infrared light-emitting diode is advanced in a straight line.

11. The robot cleaner as set forth in claim 9, wherein the light-receiving element comprises:

a light-receiving lens for condensing the light reflected by the obstruction; and

a position-sensitive detector configured such that the light condensed by the light-receiving lens is focused on the position-sensitive detector.

12. The robot cleaner as set forth in claim 9, wherein the light-emitting element is configured to emit the light at a predetermined angle, at which the degree of deviation in position of an imaginary obstruction sensed by the light-receiving element out of an effective sensing range is greater than the minimum unit distance distinguishable according to the accuracy of the signal processing unit.

13. The robot cleaner as set forth in claim 9, wherein the light-emitting element is configured to emit the light at an angle of between 10 and 15 degrees to the floor of the cleaning space.

14. The robot cleaner as set forth in claim 8, further comprising:

an incorrect signal processing unit incorporated in the information processing unit or configured to transmit a signal to the information processing unit and receive a signal from the information processing unit for determining whether the obstruction is present within the distance considering the change of the distance sensed by the at least one position sensing device while the robot cleaner is driven.

15. The robot cleaner as set forth in claim 14, wherein the incorrect signal processing unit performs an algorithm comprising:

a first step of driving the robot cleaner;

a second step of sensing an obstruction within the effective sensing range using the at least one position sensing device;

a third step of driving the robot cleaner in correspondence to the obstruction;

a fourth step of determining whether the distance from the obstruction is increased;

a fifth step of determining whether the robot cleaner approaches the obstruction; and

a sixth step of detouring the obstruction or stopping the movement of the robot cleaner when the robot cleaner approaches the obstruction.

16. The robot cleaner as set forth in claim 15, wherein, at the first step,

the second step is frequently called while the mobile robot is driven.

17. The robot cleaner as set forth in claim 15, wherein, at the fourth step,

when the distance from the obstruction is increased, the process returns to the second step, and

when the distance from the obstruction is not increased, the process moves to the fifth step.

18. The robot cleaner as set forth in claim 7, wherein the at least one position sensing device comprises a plurality of position sensing devices, some of which are configured such that the angles between lights emitted from the respective position sensing devices and the floor of the cleaning space are different.

19. The robot cleaner as set forth in claim 7, wherein the at least one position sensing device comprises a plurality of position sensing devices, some of which are configured such that the heights of the respective position sensing devices from the floor of the cleaning space are different.

20. The robot cleaner as set forth in claim 7, wherein the at least one position sensing device comprises a plurality of position sensing devices, some of which are configured such that the heights of the respective position sensing devices from the floor of the cleaning space are the same, and the angles between lights emitted from the respective position sensing devices disposed at the same height and the floor of the cleaning space are the same.

21. The robot cleaner as set forth in claim 7, wherein the at least one position sensing device comprises a plurality of position sensing devices, some of which are configured to emit light in the same direction although the heights and the light-emitting angles of the respective position sensing devices are different.