METHOD AND SYSTEM FOR NAVIGATING A ROBOTIC GARDEN TOOL

• US 20130006419A1
• Filed: 03/17/2011
• Published: 01/03/2013
• Est. Priority Date: 03/17/2010
• Status: Active Grant

• Current Assignee: Husqvarna AB (HUSQVARNA)
• Original Assignee: Husqvarna AB (HUSQVARNA)
• Inventors: Strandberg, Stefan, Bergström, Jonas, Jägenstedt, Patrik, Kamfors, Mattias
• Granted Patent: US 8,938,318 B2
• Time in Patent Office: Days
• US Class Current: 700/245
• CPC Class Codes: A01D 34/008 for automated or remotely controlled operation
• CPC Class Codes: G05D 1/0265 using buried wires
• CPC Class Codes: G05D 1/0278 using satellite positioning signals, e.g. GPS

Abstract

The present invention relates to a method (300) and a system (100) for navigating a robotic garden tool (202) based on one or more operating parameters for subareas (210-218) within the working area (204) and a current location of the robotic garden tool (202). The working area (204) is provided with a signal source (104) corresponding to which a sensor unit (106) is provided in the robotic garden tool (202) for detecting the one or more signals (102) from the signal source (104). The robotic garden tool (202) may include a low-accuracy positioning device (110) for providing co-ordinates of various subareas (210-218) and at any given instant, an approximate location of the robotic garden tool (202). The robotic garden tool (202) further includes a processor means (114) for comparing the coordinates of the subareas (210-218) and the approximate position of the robotic garden tool (202) to determine a current location of the robotic garden tool (202) in the working area (204).

Claims

1. A method for navigating a robotic garden tool operating in a lawn within a predetermined working area defined by boundaries, which robotic garden tool is provided with at least one sensor unit configured to detect the boundaries, and wherein the robotic garden tool is configured to operate in the working area in an irregular pattern,

the method comprising:

dividing the working area into subareas;

providing the robotic garden tool with a low-accuracy positioning device for defining the subareas based on coordinates from the low-accuracy positioning device in the robotic garden tool;

storing the coordinates for the subareas in the robotic garden tool,

receiving coordinates for an approximate position of the robotic garden tool from the low-accuracy positioning device; and

providing the robotic garden tool with a processor for comparing the stored coordinates for the subareas, with the coordinates for an approximate position of the robotic garden tool from the low-accuracy positioning device, to determine in which subarea the robotic garden tool is at present.

2. A method according claim 1 further comprising providing the robotic garden tool with one or more operating parameters for each of the subareas.

3. A method according to claim 2, wherein the one or more operating parameters comprises cutting heights for each of the subareas.

4. A method according to claim 2, wherein the one or more operating parameters comprises a specific time at which each of the subareas is to be cut.

5. A method according to claim 2, wherein the one or more operating parameters comprises an order in which the subareas is to be cut.

6. A method according to claim 2, wherein the one or more operating parameters is the time intervals between successive cuttings for each of the subareas.

7. A method according to claim 2, wherein the one or more operating parameters comprises restricting the access of the robotic garden tool to different subareas at different times.

8. A method according to claim 1 further comprising generating a low-accuracy map of the working area based on the coordinates for the subareas and the boundaries.

9. A method according to claim 8, wherein the robotic garden tool is configured to use the generated map to find a remote area within the working area or a charging station within the working area.

10. A method according to claim 1, wherein the boundaries defines the working area via physical fences, fixed objects, a boundary wire, which boundary wire sends electrical signals, or through surface determination, wherein the at least one sensor unit on the robotic garden tool is configured to detect the boundaries.

11. A method according to claim 1, wherein the robotic garden tool is configured to perform irregular operation within a subarea before continuing to another subarea within the working area.

12. A system for navigating a robotic garden tool operating in a lawn within a predetermined working area defined by boundaries, which working area is divided into subareas, wherein the robotic garden tool) is configured to operate in the working area in an irregular pattern, the system comprising:

a signal source, configured to send one or more signals for defining the boundaries of the working area;

at least one sensor unit provided on the robotic garden tool to detect the boundaries based on the one or more signals provided by the signal source;

a low-accuracy positioning device for defining the subareas based on the coordinates from the low-accuracy positioning device, and wherein the low-accuracy local positioning device is further configured to provide an approximate position of the robotic garden tool in a subarea; and

a control unit provided on the robotic garden tool, where in the control unit comprises at least one processor and a memory;

wherein the processor is configured to compare the coordinates for the subareas with the coordinates for an approximate position of the robotic garden tool from the low-accuracy positioning device, to determine in which subarea the robotic garden tool is at present.

13. A system according to claim 12, wherein the control unit is configured to generate a map based on the coordinates from the low-accuracy positioning device and the one or more signals received from the signal source.

14. A system according to claim 12, wherein the control unit is configured to generate one or more commands based at least in part on the location of the robotic garden tool.

15. A system according to claim 12, wherein the low-accuracy positioning device is a standard GPS device.

16. A system according to claim 12, wherein the accuracy of the low-accuracy positioning device is less than ±

10 m.

17. A system according to claim 12, wherein the accuracy of the low-accuracy positioning device is less than ±

3 m.

18. A system according to claim 12, wherein the accuracy of the low-accuracy positioning device is less than ±

1 m.

19. A system according to claim 12, wherein the accuracy of the low-accuracy positioning device is less than ±

0.1 m.

20. A system according to claim 12, wherein the robotic garden tool is a robotic lawnmower.