Circuit for estimating position and orientation of a mobile object

• US 7,148,458 B2
• Filed: 03/25/2005
• Issued: 12/12/2006
• Est. Priority Date: 03/29/2004
• Status: Active Grant

• Current Assignee: iRobot Corporation
• Original Assignee: Evolution Robotics Inc. (iRobot Corporation)
• Inventors: Brown, Joe, Schell, Steve, Witman, Robert
• Primary Examiner(s): Luu, Thanh X.
• Application Number:
  US11/090,430
• Publication Number:
  US 20050211880A1
• Time in Patent Office: 627 Days
• Field of Search: 250/203.3, 250/214.A, 702150-153, 382/103, 356/614, 356/622
• US Class Current: 250/203.3
• CPC Class Codes: H03F 3/087 with IC amplifier blocks H03F3/085 takes precedence

Abstract

A circuit system for estimating position and orientation of a mobile object based on lights from a plurality of external light sources. The circuit comprises a position-sensitive light sensor for detecting the light sources and generating a first signal, an analog filter and amplification module (“AFA”) for filtering and amplifying the first signal and generating a second signal, a digital signal processor (“DSP”) for generating a coordinate system by extracting frequency components from the second signal.

Claims

1. A circuit system for estimating position and orientation of a mobile object based on lights from a plurality of external light sources, comprising:

a position-sensitive light sensor, said sensor being disposed to detect said light sources and generate a first signal;

an analog filter and amplification module (“

AFA”

), said AFA being disposed to filter and amplify said first signal and generate a second signal;

a digital signal processor (“

DSP”

), said DSP being adapted to generate a coordinate system by extracting frequency components from said second signal.

2. The circuit system of claim 1, wherein said position-sensitive light sensor comprises a quad photo diode detector (“

PD”

).

3. The circuit system of claim 1, wherein said position-sensitive light sensor comprises a plurality of photodiodes.

4. The circuit system of claim 1, wherein said position-sensitive light sensor comprises a plurality of position-sensitive detectors (“

PSD”

).

5. The circuit system of claim 1, wherein said DSP generates said coordinate system by extracting frequency components from said second signal and calculating where said lights from said light sources are detected by said position-sensitive light sensor.

6. The circuit system of claim 4, wherein said DSP extracts said frequency components by using the Goertzel algorithm.

7. The circuit system of claim 4, wherein said DSP extracts said frequency components by using FFT.

8. The circuit system of claim 4, wherein said DSP extracts said frequency components by using DFT.

9. The circuit system of claim 1, wherein said AFA comprises:

a transimpedance amplifier (“

TIA”

), being disposed to amplify said first signal from said position-sensitive light sensor to generate its output;

a first passive high-pass filter (“

1^st PHP”

), said 1^st PHP being disposed to remove DC bias from the output of said TIA and generate its output;

a passive notch filter (“

PNF”

), disposed to remove noise signals between a predetermined range of frequencies from the output of said 1^st PHP and generate its output;

a first gain amplifier, coupled to said PNF, being disposed to amplify the output from said PNF and generate its output;

a second passive high-pass filter (“

2^nd PHP”

), being disposed to remove DC bias from the output of said PNF and generate its output;

a second gain amplifier, coupled to said 2^nd PHP, being disposed to amplify the output from said 2^nd PHP and generate its output;

a passive low-pass filter (“

PLP”

), being disposed to remove signals above a predetermined frequency from the output of said gain amplifier and generate its output.

10. The circuit system of claim 9, said AFA further comprising:

a first buffer, coupled between said 1^st PHP and said PNF, disposed to reduce interaction between said 1^st PHP and said passive notch filter.

11. The circuit system of claim 10, wherein said first buffer is an op-amp configured as a voltage follower circuit with no gain.

12. The circuit system of claim 9, wherein said PNF is implemented with detuned values to widen said predetermined range of frequencies.

13. A circuit system for estimating position and orientation of a mobile object based on lights from a plurality of external light sources, comprising:

a position-sensitive light sensor, said sensor being disposed to detect said light sources and generate a first signal;

an analog filter and amplification module (“

AFA”

), said AFA being disposed to filter and amplify said first signal and generate a second signal, said AFA comprising;

a transimpedance amplifier (“

TIA”

), being disposed to amplify said first signal from said position-sensitive light sensor to generate its output;

a first passive high-pass filter (“

1^st PHP”

), said 1^st PHP being disposed to remove DC bias from the output of said TIA and generate its output;

a passive notch filter (“

PNF”

), disposed to remove noise signals between a predetermined range of frequencies from the output of said 1^st PHP and generate its output;

a first gain amplifier, being disposed to amplify the output from said PNF and generate its output;

a second passive high-pass filter (“

2^nd PHP”

), being disposed to remove DC bias from the output of said PNF and generate its output;

a second gain amplifier, being disposed to amplify the output from said 2^nd PHP and generate its output;

a passive low-pass filter (“

PLP”

), being disposed to remove signals above a predetermined frequency from the output of said gain amplifier and generate its output;

a first buffer, coupled between said 1^st PHP and said PNF, disposed to reduce interaction between said 1^st PHP and said passive notch filter;

a second buffer, coupled between said PNF and said 2^nd PHP, disposed to reduce interaction between said PNF and said 2^nd PHP;

a digital signal processor (“

DSP”

), said DSP being adapted to generate a coordinate system by extracting frequency components from the output of said PLP.

14. A circuit system of claim 13, wherein said first buffer is an op-amp configured as a voltage follower circuit with no gain.

15. A circuit system of claim 13, wherein said PNF is implemented with detuned values to widen said predetermined range of frequencies.

16. A circuit system of claim 13, wherein said DSP generates said coordinate system by extracting frequency components from said second signal and calculating where said lights from said light sources are detected by said position-sensitive light sensor.

17. A circuit system of claim 16, wherein said DSP extracts said frequency components by using the Goertzel algorithm.

18. A circuit system of claim 16, wherein said DSP extracts said frequency components by using an FIR filter.

19. A circuit system of claim 16, wherein said DSP extracts said frequency components by using an IIR filter.

20. The circuit system of claim 13, wherein said position-sensitive light sensor comprises a quad photo diode detector (“

PD”

).

21. The circuit system of claim 13, wherein said position-sensitive light sensor comprises a plurality of photodiodes.

22. The circuit system of claim 13, wherein said position-sensitive light sensor comprises a plurality of position-sensitive detectors (“

PSD”

).