Robotic mower boundary sensing system

• US 8,725,316 B2
• Filed: 12/21/2012
• Issued: 05/13/2014
• Est. Priority Date: 07/28/2010
• Status: Active Grant

• Current Assignee: Deere & Company
• Original Assignee: Deere & Company
• Inventors: Thompson, Jeffrey S., Rupp, Craig E.
• Primary Examiner(s): Black, Thomas
• Assistant Examiner(s): HUYNH, LUAT T
• Application Number:
  US13/724,112
• Publication Number:
  US 20130211625A1
• Time in Patent Office: 508 Days
• Field of Search: 701/2, 701/23, 701/25, 701/26, 701/24, 701/50, 901/1, 901/21
• US Class Current: 701/2
• CPC Class Codes: A01D 34/006 Control or measuring arrangements
• 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: G01S 5/0205 Details
• 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
• CPC Class Codes: Y10S 901/01 : Mobile robot

Abstract

A robotic mower boundary sensing system includes a boundary driving circuit on a charging station transmitting an encoded signal on a boundary wire, a boundary sensor on a robotic mower and including an inductor receiving the encoded signal, and a vehicle control unit on the robotic mower receiving the encoded signal from the boundary sensor and decoding the signal and cross correlating the received signal to determine the distance of the boundary sensor from the boundary wire.

Claims

1. A robotic mower boundary sensing system, comprising:

a boundary driving circuit on a charging station transmitting an encoded signal on a boundary wire;

a boundary sensor on the robotic mower and including an inductor receiving the encoded signal; and

a vehicle control unit on the robotic mower receiving the encoded signal from the boundary sensor, converting waveform data of the encoded signal from a time domain to a frequency domain, and verifying an identification of the converted signal in the frequency domain against a stored identification signal.

2. The robotic mower boundary sensing system of claim 1 wherein converting the waveform data from the time domain to the frequency domain includes running a Fast Fourier Transform on the data, multiplying the Fast Fourier Transform results together, and running an inverse Fast Fourier Transform on the result of that product.

3. The robotic mower boundary sensing system of claim 1 further comprising converting waveform data of the stored identification from the time domain to the frequency domain.

4. A robotic mower boundary sensing system, comprising:

an outer boundary wire connected to a charging station;

the outer boundary wire providing a signal that is detected by a boundary sensor on the robotic mower; and

a vehicle control unit connected to the boundary sensor that verifies identification of the signal detected by the boundary sensor against an known identification signal stored in a vehicle control unit memory, by converting waveform data from the time domain into the frequency domain, for the signal detected by the boundary sensor and a known identification signal stored in the vehicle control unit memory.

5. The robotic mower boundary sensing system of claim 4 wherein the vehicle control unit runs a Fast Fourier Transform on the waveform data, multiplies the Fast Fourier Transform results together, and runs an inverse Fast Fourier Transform on the result of that product.

6. A robotic mower boundary sensing system, comprising:

a vehicle control unit that cross correlates a known waveform with a sampled waveform from at least one boundary sensor on the robotic mower by converting the known waveform data and the sampled waveform data from the time domain into the frequency domain, and verifying an identification of the sampled waveform from each boundary sensor against an identification stored in a vehicle control unit memory.

7. The robotic mower boundary sensing system of claim 6 wherein the vehicle control unit determines the distance of each boundary sensor to a boundary wire by determining a difference in signal strength between the known waveform data at a known distance to the boundary wire and the sampled waveform data.