Robotic mower navigation system

• US 9,788,481 B2
• Filed: 10/28/2014
• Issued: 10/17/2017
• Est. Priority Date: 10/28/2014
• Status: Active Grant

• Current Assignee: Deere & Company
• Original Assignee: Deere & Company
• Inventors: Das, Colin E., Johnson, David A.
• Primary Examiner(s): Black, Thomas G
• Assistant Examiner(s): LOUIE, WAE LENNY
• Application Number:
  US14/525,302
• Publication Number:
  US 20160113195A1
• Time in Patent Office: 1,085 Days
• Field of Search: 701 22, 701 23, 700258, 700248, 700245
• 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 1/0261 using magnetic plots
• CPC Class Codes: G05D 1/0265 using buried wires

Abstract

A robotic mower navigation system has a plurality of landmark tags sequentially spaced along or inside a boundary wire. Each landmark tag has a unique identifier. The robotic mower has a detector for detecting the landmark tags, and a vehicle control unit having memory storing data for each of the landmark tags including the unique identifiers, a departure angle and a distance from the landmark tag to another non-sequential landmark tag. The vehicle control unit determines the shortest route to a specified destination based on the stored landmark tag data.

Claims

1. A robotic mower navigation system, comprising:

a plurality of landmark tags sequentially spaced along a boundary wire, each landmark tag having a unique identifier;

a robotic mower having a detector for detecting the landmark tags; and

a vehicle control unit on the robotic mower that directs the robotic mower to follow the boundary wire and determines a distance between the sequentially spaced landmark tags, and that directs the robotic mower to make a plurality of passes inside the boundary wire and determines a departure angle and a distance between each landmark tag and at least one non-sequentially spaced landmark tag, and determines a shortest route between the landmark tags to a specified destination.

2. The robotic mower navigation system of claim 1 wherein the specified destination is a robotic mower docking station.

3. The robotic mower navigation system of claim 1 wherein the specified destination is a landmark tag for a launch point.

4. The robotic mower navigation system of claim 1 wherein the landmark tags are passive RFID tags.

5. The robotic mower navigation system of claim 1 wherein the vehicle control unit commands a traction drive on the robotic mower to drive the robotic mower to the specified destination.

6. A robotic mower navigation system, comprising:

a vehicle control unit on a robotic mower that directs the robotic mower to follow a path between a plurality of adjacent landmark tags and determines a distance between each of the plurality of adjacent landmark tags located within or along a yard perimeter, each of the plurality of landmark tags being adjacent to two landmark tags and non-adjacent to a plurality of other landmark tags;

the stored data including a unique identifier for each landmark tag, the vehicle control unit directing the robotic mower to make passes inside the yard perimeter and determine a distance from each landmark tag to at least one other non-adjacent landmark tag, and a departure angle from each landmark tag to at least one other non-adjacent landmark tag;

the vehicle control unit determining a route between the landmark tags to a docking station based on the distances and departure angles.

7. The robotic mower navigation system of claim 6 wherein each landmark tag is a passive RFID tag, and further comprising an RFID detector on the robotic mower.

8. The robotic mower navigation system of claim 6 wherein the vehicle control unit commands the robotic mower to go from a current location to a landmark tag before the vehicle control unit determines the route to the docking station.

9. The robotic mower navigation system of claim 6 further comprising a boundary sensor on the robotic mower that provides the vehicle control unit with signals regarding an angle of the boundary sensor with respect to a known axis.

10. A robotic mower navigation system, comprising:

a boundary sensor on a robotic mower that senses an angle to a boundary wire; and

a vehicle control unit on the robotic mower directing the robotic mower to make passes inside the boundary wire and that determines the angle and a distance between a landmark tag on the boundary wire and a plurality of other non-sequential landmark tags on the boundary wire, and directing the robotic mower on a path between selected non-sequential landmark tags.

11. The robotic mower navigation system of claim 10 wherein the vehicle control unit directs the robotic mower to a specified destination using the distance and the angle between a landmark tag and another non-sequential landmark tag on the boundary wire.

12. The robotic mower navigation system of claim 11 wherein the vehicle control unit computes the shortest distance to the specified destination using the distance and the angle between a landmark tag and another non-sequential landmark tag on the boundary wire.

13. The robotic mower navigation system of claim 10 wherein the boundary sensor has at least two pickup coils arranged in different orientations.

14. The robotic mower navigation system of claim 10 wherein the landmark tags are RFID tags, and further comprising an RFID detector on the robotic mower.