BOUNDARY SIGNAL DETECTION

• US 20170045612A1
• Filed: 08/10/2015
• Published: 02/16/2017
• Est. Priority Date: 08/10/2015
• Status: Active Grant

• Current Assignee: Board of Trustees of The University of Illinois, Deere & Company
• Original Assignee: Board of Trustees of The University of Illinois, Deere & Company
• Inventors: Das, Colin E., Trenhaile, Brent R.
• Granted Patent: US 9,903,947 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A01D 34/008 for automated or remotely controlled operation
• CPC Class Codes: G01S 13/881 for robotics
• CPC Class Codes: G05D 1/0088 characterized by the autonomous decision making process, e.g. artificial intelligence, predefined behaviours using knowledge based models G06N5/00
• CPC Class Codes: G05D 1/0265 using buried wires

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.

Claims

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 system comprising:

electronics to;

convert an acquired candidate boundary signal from a time domain to a frequency domain to identify at least one embedded frequency in the candidate signal;

compare the at least one embedded frequency in the candidate signal to at least one predetermined embedded frequency of the valid boundary signal; and

identify the candidate signal as the valid boundary signal based upon the comparison.

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

3. The system of claim 1, wherein the converting of the candidate signal from a time domain to a frequency domain comprises:

carrying out a fast Fourier transform of the candidate signal;

computing the power spectrum of the fast Fourier transform; and

normalizing the fast Fourier transform power spectrum of the candidate signal.

4. The system of claim 1, wherein the converting of the candidate signal from a time domain to a frequency domain comprises:

carrying out a fast Fourier transform of the candidate signal;

computing the power spectrum of the fast Fourier transform; and

normalizing the fast Fourier transform power spectrum of the candidate signal; and

wherein the comparing of the at least one embedded frequency in the candidate 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 signal proximate to predetermined fundamental frequencies of the valid boundary signal to a magnitude threshold, wherein the identification of the candidate signal as the valid boundary signal is based upon the comparison to the magnitude threshold.

5. The system of claim 1, wherein the converting of the candidate signal from a time domain to a frequency domain comprises:

carrying out a fast Fourier transform of the candidate signal;

computing the power spectrum of the fast Fourier transform; and

normalizing the fast Fourier transform power spectrum of the candidate signal; and

wherein the comparing of the at least one embedded frequency in the candidate 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 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 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 system of claim 1 further comprising a boundary driving circuit to transmit the valid signal indicating the boundary for the target region.

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

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

9. The system of claim 1 further comprising a vehicle having a propulsion unit, the vehicle carrying a sensor to acquire the candidate boundary signal.

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

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

12. 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 signal;

compare the at least one embedded frequency in the candidate signal to at least one predetermined embedded frequency of the valid boundary signal; and

identify the candidate 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 signals identified as the valid boundary signal.

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

14. The robotic appliance of claim 12, wherein the converting of the candidate signal from a time domain to a frequency domain comprises:

carrying out a fast Fourier transform of the candidate signal;

compute the power spectrum of the fast Fourier transform; and

normalizing the fast Fourier transform power spectrum of the candidate signal.

15. The robotic appliance of claim 12, wherein the converting of the candidate signal from a time domain to a frequency domain comprises:

carrying out a fast Fourier transform of the candidate signal;

compute the power spectrum of the fast Fourier transform; and

normalizing the fast Fourier transform power spectrum of the candidate signal; and

wherein the comparing of at least one embedded frequency in the candidate 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 signal proximate predetermined fundamental frequencies of the valid boundary signal to a magnitude threshold, wherein the identification of the candidate signal as the valid boundary signal is based upon the comparison to the magnitude threshold.

16. The robotic appliance of claim 12, wherein the converting of the candidate signal from a time domain to a frequency domain comprises:

carrying out a fast Fourier transform of the candidate signal;

compute the power spectrum of the fast Fourier transform; and

normalizing the fast Fourier transform power spectrum of the candidate signal; and

wherein the comparing of the at least one embedded frequency in the candidate 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 signal proximate 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 signal as the valid boundary signal is based upon the comparison of the identified peaks to the frequency location threshold and magnitude threshold.

17. A vehicle position detection system comprising:

a boundary driving circuit to transmit a valid signal indicating a boundary for a target region;

a vehicle to move relative to the boundary for the target region, the vehicle comprising;

a boundary sensor carried by the robotic appliance, the boundary sensor comprising an inductor to receive a candidate boundary signal; and

electronics to;

determine whether a candidate boundary signal is the valid boundary signal for the target region or is an extraneous boundary signal for a neighboring region by;

converting the candidate signal from a time domain to a frequency domain to identify at least one embedded frequency in the candidate signal;

comparing the at least one embedded frequency in the candidate signal to at least one predetermined embedded frequency of the valid boundary signal; and

identifying the candidate signal as the valid boundary signal based upon the comparison; and

determine a position of the vehicle based upon candidate signals identified as the valid boundary signal.

18. The system of claim 17, wherein the valid signal indicates an outer boundary for the target region.

19. The system of claim 17, wherein the valid signal indicates an inner boundary for the target region

20. The system of claim 17, wherein the boundary driving circuit transmits the valid signal on a boundary wire.