Boundary signal detection

Patent metadata

Field	Value
Publication number	US-9903947-B2
Application number	US-201514822821-A
Country	US
Kind code	B2
Filing date	Aug 10, 2015
Priority date	Aug 10, 2015
Publication date	Feb 27, 2018
Grant date	Feb 27, 2018

Abstract

A boundary signal detection system distinguishes a valid boundary signal for a target region from an extraneous boundary signal for a neighboring region. The system includes electronics that convert the candidate signal from a time domain to a frequency domain to identify at least one embedded frequency in the candidate, that compare the at least one embedded frequency in the candidate signal to at least one predetermined embedded frequency of the valid boundary signal, and that identify the candidate signal as the valid boundary signal based upon the comparison.

First claim

What is claimed is:

1. A boundary signal detection system to distinguish a valid boundary signal for a target region from an extraneous boundary signal for a neighboring region, the boundary signal detection system comprising:
a vehicle having a propulsion unit, the vehicle carrying a sensor to acquire a candidate boundary signal; and
electronics to:
convert the acquired candidate boundary signal from a time domain to a frequency domain to identify at least one embedded frequency in the candidate boundary signal;
compare the at least one embedded frequency in the candidate boundary signal to at least one predetermined embedded frequency of the valid boundary signal; and
identify the candidate boundary signal as the valid boundary signal based upon the comparison.

2. The boundary signal detection system of claim 1 , wherein the converting of the candidate boundary signal from a time domain to a frequency domain comprises carrying out a Fourier transform of the candidate boundary signal.

3. The boundary signal detection system of claim 1 , wherein the converting of the candidate boundary signal from a time domain to a frequency domain comprises:
carrying out a fast Fourier transform of the candidate boundary signal;
computing the power spectrum of the fast Fourier transform; and
normalizing the fast Fourier transform power spectrum of the candidate boundary signal.

4. The boundary signal detection system of claim 1 , wherein the converting of the candidate boundary signal from a time domain to a frequency domain comprises:
carrying out a fast Fourier transform of the candidate boundary signal;
computing the power spectrum of the fast Fourier transform; and
normalizing the fast Fourier transform power spectrum of the candidate boundary signal; and
wherein the comparing of the at least one embedded frequency in the candidate boundary signal to at least one predetermined embedded frequency of the valid boundary signal comprises:
comparing the normalized fast Fourier transform power spectrum of the candidate boundary signal, proximate to predetermined fundamental frequencies of the valid boundary signal, to a magnitude threshold, wherein the identification of the candidate boundary signal as the valid boundary signal is based upon the comparison to the magnitude threshold.

5. The boundary signal detection system of claim 1 , wherein the converting of the candidate boundary signal from a time domain to a frequency domain comprises:
carrying out a fast Fourier transform of the candidate boundary signal;
computing the power spectrum of the fast Fourier transform; and
normalizing the fast Fourier transform power spectrum of the candidate boundary signal; and
wherein the comparing of the at least one embedded frequency in the candidate boundary signal to at least one predetermined embedded frequency of the valid boundary signal comprises:
identifying peaks in the normalized fast Fourier transform power spectrum of the candidate boundary signal proximate to predetermined fundamental frequencies of the valid boundary signal; and
comparing the identified peaks to a frequency location threshold and a magnitude threshold, wherein the identification of the candidate boundary signal as the valid boundary signal is based upon the comparison of the identified peaks to the frequency location threshold and magnitude threshold.

6. The boundary signal detection system of claim 1 further comprising a boundary driving circuit to transmit the valid boundary signal indicating a boundary for the target region.

7. The boundary signal detection system of claim 1 , further comprising a boundary driving circuit to transmit a valid boundary signal indicating a boundary for the target region, wherein the boundary driving circuit transmits the valid boundary signal on a boundary wire.

8. The boundary signal detection system of claim 1 further comprising a boundary driving circuit to transmit the valid boundary signal indicating the boundary for the target region, wherein the valid boundary signal comprises a plurality of embedded frequencies, the plurality of embedded frequencies being whole multiples of one another.

9. The boundary signal detection system of claim 1 further comprising a vehicle having a propulsion unit and carrying a sensor to acquire the acquired candidate boundary signal, wherein the electronics are further to output control signals to the propulsion unit to direct movement of the vehicle, the control signals being based upon candidate boundary signals identified as the valid boundary signal.

10. The boundary signal detection system of claim 1 further comprising a vehicle having a propulsion unit and carrying a sensor to acquire the acquired candidate boundary signal, the electronics to further determine a position of the vehicle based upon candidate boundary signals identified as the valid boundary signal.

11. A robotic appliance comprising:
a propulsion unit to move the robotic appliance;
a boundary sensor carried by the robotic appliance, the boundary sensor comprising an inductor to receive a candidate boundary signal;
electronics carried by the robotic appliance to:
convert the candidate signal from a time domain to a frequency domain to identify at least one embedded frequency in the candidate boundary signal;
compare the at least one embedded frequency in the candidate boundary signal to at least one predetermined embedded frequency of a valid boundary signal; and
identify the candidate boundary signal as the valid boundary signal based upon the comparison; and
output control signals to the propulsion unit to direct movement of the robotic appliance, the control signals being based upon candidate boundary signals identified as the valid boundary signal.

12. The robotic appliance of claim 11 , wherein the converting of the candidate boundary signal from a time domain to a frequency domain comprises carrying out a Fourier transform of the candidate boundary signal.

13. The robotic appliance of claim 11 , wherein the converting of the candidate boundary signal from a time domain to a frequency domain comprises:
carrying out a fast Fourier transform of the candidate boundary signal;
compute the power spectrum of the fast Fourier transform; and
normalizing the fast Fourier transform power spectrum of the candidate boundary signal.

14. The robotic appliance of claim 11 , wherein the converting of the candidate boundary signal from a time domain to a frequency domain comprises:
carrying out a fast Fourier transform of the candidate boundary signal;
compute the power spectrum of the fast Fourier transform; and
normalizing the fast Fourier transform power spectrum of the candidate boundary signal; and
wherein the comparing of at least one embedded frequency in the candidate boundary signal to at least one predetermined embedded frequency of the valid boundary signal comprises:
comparing the normalized fast Fourier transform power spectrum of the candidate boundary signal, proximate predetermined fundamental frequencies of the valid boundary signal, to a magnitude threshold, wherein the identification of the candidate boundary signal as the valid boundary signal is based upon the comparison to the magnitude threshold.

15. The robotic appliance of claim 11 , wherein the converting of the candidate boundary signal from a time domain to a frequency domain comprises:
carrying out a fast Fourier transform of the candidate boundary signal;
compute the power spectrum of the fast Fourier transform; and
normalizing the fast Fourier transform power spectrum of the candidate boundary signal;

Assignees

• Deere & Co
• Univ Illinois
• Deere & Co

Inventors

• Das Colin E
• Trenhaile Brent R

Classifications

• G05D1/0088

  characterized by the autonomous decision making process, e.g. artificial intelligence, predefined behaviours (using knowledge based models G06N5/00) · CPC title

• G01S13/881 Primary

  for robotics · CPC title

• A01D34/008

  for automated or remotely controlled operation · CPC title

• G05D1/0265 Primary

  using buried wires · CPC title

• G05D1/0229

  in combination with fixed guiding means · CPC title