Method and system for guiding a robotic garden tool to a predetermined position

• US 8,942,862 B2
• Filed: 03/17/2010
• Issued: 01/27/2015
• Est. Priority Date: 03/17/2010
• Status: Active Grant

• Current Assignee: Husqvarna AB (HUSQVARNA)
• Original Assignee: Husqvarna AB (HUSQVARNA)
• Inventors: Markusson, Olle, Andersson, Gunnar, Pettersson, Patrick, ster, Johan, Jgenstedt, Patrik, Adolfsson, Johan
• Primary Examiner(s): NGUYEN, TAN QUANG
• Application Number:
  US13/635,459
• Publication Number:
  US 20130066484A1
• Time in Patent Office: 1,777 Days
• Field of Search: 701/2, 701/23, 701/24, 701/25, 701/26, 701/22, 700/245, 56/102, 318/568.12
• US Class Current: 701/2
• CPC Class Codes: A01D 34/008 for automated or remotely controlled operation
• 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 1/0265 using buried wires

Abstract

The present invention relates to a method (400) and a system (100) for guiding a robotic garden tool to a predetermined position. The robotic garden tool includes a control unit (104) and a sensor unit (102) to detect guiding signals. The sensor unit (102) detects a first guiding signal (110) from a first signal source (106) and the robotic garden tool follows the first guiding signal (110) at a variable distance from the first signal source (106) towards the predetermined position. While within a predetermined distance (D) from the predetermined position, the sensor unit (102) detects a second guiding signal (112) from a second signal source (108). Within the predetermined distance (D), the robotic garden tool follows one of the first and the second guiding signals (110 or 112) towards the predetermined position at a pre-configured distance from the corresponding signal source.

Claims

1. A method for guiding a robotic garden tool to a predetermined position, wherein the robotic garden tool comprising a control unit and at least one sensor unit for wirelessly detecting guiding signals, the method comprises the steps of:

detecting a first guiding signal from a first signal source;

following the first guiding signal at a variable distance from the first signal source towards the predetermined position in response to a command from the control unit;

detecting a second guiding signal from a second signal source, wherein the second guiding signal is detected within a predetermined distance from the predetermined position; and

following one of the first and the second guiding signals at a pre-configured distance from the corresponding signal source towards the predetermined position.

2. A method according to claim 1, wherein detecting the first guiding signal from the first signal source comprises the step of detecting the first guiding signal from a first guide wire.

3. A method according to claim 2, wherein following the first guiding signal comprises the step of moving the robotic garden tool along the first guide wire at the variable distance from the first guide wire.

4. A method according to claim 1, wherein detecting the second guiding signal comprises the step of detecting the second guiding signal from a second guide wire within the predetermined distance from the predetermined position.

5. A method according to claim 4, wherein following one of the first and the second guiding signals comprises the step of moving the robotic garden tool at a pre-configured distance from one of the first guide wire or the second guide wire based on a command from the control unit in response to one of the first and the second guiding signals.

6. A method according to claim 1, wherein the second signal source is located at the predetermined position.

7. A method according to claim 6, wherein detecting the second guiding signal within the predetermined distance comprises the step of detecting the second guiding signal from an antenna mounted at the predetermined position.

8. A method according to claim 6, wherein following one of the first and the second guiding signals comprises moving the robotic garden tool at a pre-configured distance from a first guide wire based on a command from the control unit in response to one of the first and the second guiding signals.

9. A method according to claim 1, wherein the predetermined distance is in a range from about 0.5 meters to about 4 meters from the predetermined position.

10. A method according to claim 1, providing a charging station at the predetermined position.

11. A system for guiding a robotic garden tool to a predetermined position, the system comprising

a first signal source, configured to send a first guiding signal for guiding the robotic garden tool towards the predetermined position;

a second signal source, configured to send a second guiding signal for guiding the robotic garden tool towards the predetermined position;

at least one sensor unit provided on the robotic garden tool to detect the first guiding signal and the second guiding signal; and

a control unit provided on the robotic garden tool to generate a command based in response to at least one of the first guiding signal and the second guiding signal;

wherein the robotic garden tool is configured to follow the first guiding signal at a variable distance from the first signal source towards the predetermined position in response to the command from the control unit; and

the robotic garden tool is further configured to, when within a predetermined distance from the predetermined position, follow one of the first and second guiding signals at a pre-configured distance from the corresponding signal source to the predetermined position in response to the command from the control unit.

12. A system according to claim 11, wherein the first signal source is a first guide wire.

13. A system according to claim 11, wherein the second signal source is a second guide wire.

14. A system according to claim 11, wherein the first signal source and the second signal source are placed together within the predetermined distance from the predetermined position and then oriented in different directions.

15. A system according to claim 11, wherein the second signal source is mounted at the predetermined position.

16. A system according to claim 15, wherein the second signal source is an antenna mounted at the predetermined position.

17. A system according to claim 11, wherein the predetermined distance is in a range from about 0.5 meters to about 4 meters from the predetermined position.

18. A system according to claim 11, wherein the predetermined position is the position of a charging station.

19. A system according to claim 11, wherein the robotic garden tool is a robotic lawnmower.