Robotic mower home finding system

• US 8,433,468 B2
• Filed: 07/28/2010
• Issued: 04/30/2013
• Est. Priority Date: 07/28/2010
• Status: Active Grant

• Current Assignee: Deere & Company
• Original Assignee: Deere & Company
• Inventors: Johnson, David A., Thompson, Jeffrey S.
• Primary Examiner(s): Tarcza, Thomas
• Assistant Examiner(s): Khatib, Rami
• Application Number:
  US12/845,314
• Publication Number:
  US 20120029753A1
• Time in Patent Office: 1,007 Days
• Field of Search: 701 23- 26, 701/50, 701408-411, 701416-417, 701/423, 701/424, 701/466, 701/494, 701/514, 701/518, 701/519, 701/521, 701/523, 701/527, 701300-302, 318/567, 31856811-56813, 31856816-56818, 31856822-56823, 318/580, 56/1, 56/102.R, 56/102.D, 56/102.F, 56/102.A, 56/102.J, 563/14, 35613904-13908, 180167-169, 180/274, 180/280, 700/245, 700/250, 700/253, 700/258, 901/1, 901/46, 901/47, 342/357.65, 172/26
• US Class Current: 701/23
• CPC Class Codes: A01D 34/008 for automated or remotely controlled operation
• CPC Class Codes: B60L 15/20 for control of the vehicle or its driving motor to achieve a desired performance, e.g. speed, torque, programmed variation of speed
• CPC Class Codes: B60L 15/2036 Electric differentials, e.g. for supporting steering vehicles
• CPC Class Codes: B60L 2200/40 Working vehicles
• CPC Class Codes: B60L 2220/20 DC electrical machines
• CPC Class Codes: B60L 2220/46 Wheel motors, i.e. motor connected to only one wheel
• CPC Class Codes: B60L 2240/12 Speed
• CPC Class Codes: B60L 2240/22 Yaw angle
• CPC Class Codes: B60L 2240/421 Speed
• CPC Class Codes: B60L 2240/423 Torque
• CPC Class Codes: B60L 2240/547 Voltage
• CPC Class Codes: B60L 2250/16 by display
• CPC Class Codes: B60L 2260/32 Auto pilot mode
• CPC Class Codes: B60L 50/51 characterised by AC-motors
• CPC Class Codes: B60L 53/14 Conductive energy transfer
• CPC Class Codes: B60L 53/65 involving identification of vehicles or their battery types
• CPC Class Codes: B60L 58/21 having the same nominal voltage
• 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
• CPC Class Codes: Y02T 10/64 Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/70 : Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 : Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 10/72 : Electric energy management in electromobility
• CPC Class Codes: Y02T 90/12 : Electric charging stations
• CPC Class Codes: Y02T 90/14 : Plug-in electric vehicles
• CPC Class Codes: Y02T 90/16 : Information or communication technologies improving the operation of electric vehicles
• CPC Class Codes: Y02T 90/167 : Systems integrating technologies related to power network operation and communication or information technologies for supporting the interoperability of electric or hybrid vehicles, i.e. smartgrids as interface for battery charging of electric vehicles [EV] or hybrid vehicles [HEV]
• CPC Class Codes: Y04S 30/14 : Details associated with the interoperability, e.g. vehicle recognition, authentication, identification or billing

Abstract

A robotic mower home finding system includes a charging station connected to an outer boundary wire loop, and a vehicle control unit on the robotic mower that directs a traction drive system to drive the robotic mower along a path offset a specified distance from an outer boundary wire loop toward the charging station. The vehicle control unit changes the specified distance randomly or incrementally so that the robotic mower does not take the same path to the charging station each time.

Claims

1. A robotic mower home finding system, comprising:

a charging station connected to an outer boundary wire loop;

a vehicle control unit on the robotic mower that commands a traction drive system to drive the robotic mower along a path inside the outer boundary wire loop while a plurality of sensors provide signals to the vehicle control unit correlating to the distance of each of the sensors to the outer boundary wire loop until commanding the traction drive system to drive the robotic mower until the plurality of sensors find the outer boundary wire loop and follow the outer boundary wire loop along a path offset a specified distance parallel to the outer boundary wire loop until turning perpendicular to the outer boundary wire loop when the plurality of sensors detect an inner wire loop connected to the charging station, the vehicle control unit changing the specified distance each time the robotic mower returns home to the charging station.

2. The robotic mower home finding system of claim 1 wherein the vehicle control unit changes the specified distance using a randomly generated variable.

3. The robotic mower home finding system of claim 1 wherein the vehicle control unit changes the specified distance by increments each time the robotic mower returns home to the charging station.

4. The robotic mower home finding system of claim 1 wherein the vehicle control unit commanding the traction drive system to drive the robotic mower into the charging station when the robotic mower reaches the inner wire loop.

5. A robotic mower home finding system, comprising:

a plurality of boundary wire sensors connected to a vehicle control unit commanding a robotic mower to turn from a non-predetermined path within an outer boundary wire to find any location along the outer boundary wire, align the robotic mower parallel to the outer boundary wire and return to a charging station along a path adjacent the outer boundary wire, and turn perpendicular to the outer boundary wire to enter the charging station for recharging a battery pack;

the vehicle control unit varying the path each time it commands the robotic mower to return to the charging station.

6. The robotic mower home finding system of claim 5 wherein the charging station is connected to the outer boundary wire.

7. The robotic mower home finding system of claim 5 wherein the vehicle control unit varies the path based on a random variable.

8. The robotic mower home finding system of claim 5 further comprising an inner boundary wire inside and perpendicular to the outer boundary wire to mark the location of the charging station.

9. A robotic mower home finding system, comprising:

a plurality of boundary sensors providing signals to a vehicle control unit based on a distance to an outer boundary wire;

the vehicle control unit directing a pair of traction drive wheels to drive the robotic mower from a non-predetermined path inside the outer boundary wire to a location along the outer boundary wire, the vehicle control unit using signals from the plurality of boundary sensors to align the robotic mower with respect to the outer boundary wire and return to a charging station along a path at a specified distance parallel to the outer boundary wire;

the vehicle control unit changing the specified distance each time it directs the pair of traction drive wheels to drive the robotic mower to return to the charging station.

10. The robotic mower home finding system of claim 9 wherein the charging station is connected to the outer boundary wire and is marked by an inner wire loop.

11. The robotic mower home finding system of claim 9 wherein the vehicle control unit changes the specified distance randomly.

12. The robotic mower home finding system of claim 9 wherein the vehicle control unit changes the specified distance incrementally.