Improved Perimeter Marking for a Robotic Working Tool

Patent metadata

Field	Value
Publication number	US-2020042011-A1
Application number	US-201816497876-A
Country	US
Kind code	A1
Filing date	Feb 28, 2018
Priority date	Mar 28, 2017
Publication date	Feb 6, 2020
Grant date	—

Abstract

A robotic working tool comprising a sensor for detecting magnetic fields connected to a controller for controlling the operation of the robotic working tool. The controller is configured to operate according to a first control signal being transmitted through a first boundary wire and according to a second control signal being transmitted through a second boundary wire. The robotic working tool is thereby configured to operate within a composite work area comprising at least a first partial work area and a second partial work area. The first boundary wire delimits the first partial work area and the second boundary wire delimits the second partial work area. The at least first and second boundary wires provide a common perimeter for the composite work area. Analysing the magnetic fields detected by the sensor, the controller determines whether the robotic working tool is inside or outside the composite work area.

First claim

1 . A robotic working tool comprising a sensor for detecting magnetic fields connected to a controller for controlling the operation of the robotic working tool, the controller further being configured to control the robotic working tool to:
operate according to a first control signal being transmitted through a first boundary wire and operate according to a second control signal being transmitted through a second boundary wire, the robotic working tool thereby being configured to operate within a composite work area comprising at least a first partial work area and a second partial work area, wherein the first boundary wire delimits the first partial work area and the second boundary wire delimits the second partial work area, the at least first and second boundary wires providing a common perimeter for the composite work area, wherein the controller is further configured to determine whether the robotic working tool is inside or outside the composite work area based on the first control signal, the second control signal or a sum of the first control signal and the second control signal, wherein in the sum, one of the first and second control signals is inverted, wherein the controller determines that the robotic working tool is inside the composite work area if the robotic working tool determines that the robotic working tool is inside at least one partial work area, and wherein the controller determines that the robotic working tool is outside the composite work area if the robotic working tool determines that the robotic working tool is not inside at least one partial work area, and wherein the sensor is arranged to detect magnetic fields around any of the first and second boundary wires, the magnetic fields being generated by the control signal being transmitted through a respective one of the first and second boundary wires.

2 . The robotic working tool according to claim 1 , wherein the controller is further configured to determine whether the robotic working tool is inside or outside the composite work area based on polarities of the first control signal and the second control signal, wherein the controller determines that the robotic working tool is outside the composite work area if the polarities of both the first and second control signal are inverted compared to an expected polarity.

3 . The robotic working tool according to claim 1 , wherein the controller is further configured to determine that the robotic working tool is inside or outside the first partial work area based on the first control signal or a sum of the first control signal and the second control signal, wherein in the sum the second control signal is inverted, wherein the controller determines that the robotic working tool is outside the first partial work area if polarities of the first control signal are inverted or the sum is inverted compared to an expected polarity.

4 . The robotic working tool according to claim 1 , wherein the controller is further configured to determine that the robotic working tool is inside or outside the second partial work area based on the second control signal or a sum of the first control signal and the second control signal wherein sum includes the first control signal being inverted, wherein the controller determines that robotic working tool is outside the first partial work area if polarities of the second control signal are inverted or the sum is inverted compared to an expected polarity.

5 . The robotic working tool according to claim 1 , wherein the first and the second control signals are the same.

6 . The robotic working tool according to claim 1 , wherein the first and the second control signals are different.

7 . The robotic working tool according to claim 6 , wherein the second control signal is a phase shifted copy of the first control signal.

8 . The robotic working tool according to claim 1 , wherein the robotic working tool is a robotic lawnmower.

9 . The robotic working tool according to claim 1 , wherein the robotic working tool is arranged to operate according to a sum of two or more control signals, wherein the robotic working tool is configurable to operate by detecting and processing the sum of the two or more control signals as being one signal form or the robotic working tool being configurable to operate by detecting and processing the sum of the two or more control signals wherein the sum is comprised of different signal forms by splitting up a detected sum signal into a detected version of at least one of the two or more control signals.

10 . A robotic working tool system comprising a robotic working tool, a first boundary wire, a second boundary wire, a signal generator for providing a first control signal through said first boundary wire and a second control signal through said first boundary wire, wherein said robotic working tool is configured to operate in a composite work area, comprising a first partial work area delimited by the first boundary wire and a second partial work area delimited by the second boundary wire.

11 . The robotic working tool system according to claim 10 , wherein said composite work area is a continuous work area.

12 . A signal generator configured to be used in a robotic working tool system as in claim 10 .

13 . A method for use in a robotic working tool comprising a sensor for detecting magnetic fields, the method comprising:
operating the robotic working tool according to a first control signal being transmitted through a first boundary wire, and operating the robotic working tool according to a second control signal being transmitted through a second boundary wire, the robotic working tool thereby being configured to operating within a composite work area comprising at least a first partial work area and a second partial work area, wherein the first boundary wire delimits the first partial work area and the second boundary wire delimits the second partial work area, the first and second boundary wires providing a common perimeter for the composite work area, wherein the method further comprises determining whether the robotic working tool is inside or outside the composite work area based on the first control signal, the second control signal or a sum of the first control signal and the second control signal, the sum including one of the first and second control signals being inverted, wherein it is determined that the robotic working tool is inside the composite work area if the robotic working tool determines that the robotic working tool is inside at least one partial work area, and wherein it is determined that the robotic working tool is outside the composite work area if the robotic working tool determines that the robotic working tool is not inside at least one partial work area, and wherein the sensor is arranged to detect magnetic fields around any of the first and second boundary wires, the magnetic fields being generated by the control signal being transmitted through a respective one of the first and second boundary wires.

14 . A computer-readable product configured to carry computer program instructions that when loaded into and executed by a controller cause the controller to perform the method according to claim 13 .

Assignees

• Husqvarna Ab

Inventors

• äRLIG ULF
• Sjöholm Ludvig

Classifications

• A01D2101/00

  Lawn-mowers · CPC title

• A01D34/008 Primary

  for automated or remotely controlled operation · CPC title

• A01D34/00

  Mowers (combined with apparatus performing additional operations while mowing A01D37/00 - A01D41/00, A01D43/00; convertible to apparatus for purposes other than mowing or capable of performing operations other than mowing A01D42/00); Mowing apparatus of harvesters · CPC title

• G05D1/0265 Primary

  using buried wires · CPC title

• G05D1/43 Primary

  Control of position or course in two dimensions [2D] · CPC title