Sonar scanner

• US 7,688,676 B2
• Filed: 05/05/2008
• Issued: 03/30/2010
• Est. Priority Date: 08/03/2000
• Status: Expired due to Term

• Current Assignee: iRobot Corporation
• Original Assignee: iRobot Corporation
• Inventors: Allard, James, Chiappetta, Mark J.
• Primary Examiner(s): PIHULIC, DANIEL T
• Application Number:
  US12/115,229
• Publication Number:
  US 20080205194A1
• Time in Patent Office: 694 Days
• Field of Search: 367/98, 901/1, 901/46
• US Class Current: 367/98
• CPC Class Codes: B25J 13/006 by means of a wireless system for controlling one or several manipulators
• CPC Class Codes: B60G 2300/45 Rolling frame vehicles
• CPC Class Codes: B62D 61/10 with more than four wheels tractors of the low ground pressure type B62D49/002
• CPC Class Codes: B62D 61/12 with variable number of ground engaging wheels, e.g. with some wheels arranged higher than others, or with retractable wheels for manoeuvring purposes only B60S
• CPC Class Codes: G01S 15/108 using more than one pulse per sonar period
• CPC Class Codes: G01S 15/88 Sonar systems specially adapted for specific applications seismic or acoustic prospecting or detecting G01V1/00
• CPC Class Codes: G01S 7/52004 Means for monitoring or calibrating short-range imaging G01S7/5205
• CPC Class Codes: G01S 7/527 Extracting wanted echo signals Doppler systems G01S15/50

Abstract

Detecting an object using sound waves includes outputting a sound wave from a transducer, receiving an echo after outputting the sound wave, obtaining a threshold value based on the echo and plural other echoes that are within a predetermined range of the echo, and determining if the echo is a result of the sound wave based on the threshold value.

Claims

1. A method of controlling a mobile robot, the method comprising:

outputting multiple, sequential sound waves from a single transducer mounted on a mobile robot;

receiving echoes of the outputted sound waves with a receiver mounted on the mobile robot;

obtaining a threshold value based on a latest one of the echoes and previously received ones of the echoes determined to fall within a predetermined time range of the latest echo;

determining if the latest echo is a result of a latest one of the outputted sound waves based on the threshold value;

detecting the presence of an object based on the determination of whether the latest echo is a result of the latest outputted sound wave; and

controlling the mobile robot based on the detection of the presence of the object.

2. The method of claim 1, wherein obtaining the threshold value comprises:

obtaining an average that is based on the latest echo and the previously received echoes; and

modifying the average using a scaling factor.

3. The method of claim 1, wherein the previously received echoes are adjacent in time to the latest echo.

4. An apparatus for detecting an object using sound waves, the apparatus comprising:

a single transducer to output multiple, sequential sound waves and to receive echoes of the outputted sound waves; and

a processor configured to

obtain a threshold value based on a latest one of the echoes and previously received ones of the echoes determined to fall within a predetermined time range of the latest echo, and

determine if the latest echo is a result of a latest one of the outputted sound waves based on the threshold value.

5. The apparatus of claim 4, wherein obtaining the threshold value comprises:

obtaining an average that is based on the latest echo and the previously received echoes; and

modifying the average using a scaling factor.

6. The apparatus of claim 4, wherein the previously received echoes are adjacent in time to the latest echo.

7. A method of controlling a mobile robot, the method comprising:

receiving plural reflections of corresponding emissions;

determining a threshold value based on a target reflection and received reflections determined to each result from a corresponding emission;

comparing the target reflection to the threshold value, the target reflection comprising one of the plural reflections;

determining if the target reflection is a reflection of a latest emission based on the comparison to the threshold value;

detecting the presence of an object based on the determination of whether the echo is a result of the latest outputted sound wave; and

controlling the mobile robot based on the detection of the presence of the object.

8. The method of claim 7, wherein determining the threshold value comprises averaging magnitudes of the plural reflections.

9. The method of claim 8, wherein determining the threshold value comprises applying a scaling factor to an average of the magnitudes of the plural reflections.

10. The method of claim 7, wherein:

the plural reflections comprise a first reflection, followed by a second reflection, followed by a third reflection; and

the target reflection comprises the second reflection;

wherein the first reflection, the second reflection, and the third reflection are adjacent in time.

11. The method of claim 7, wherein the emissions comprise sound waves and the plural reflections comprise echoes of the sound waves.

12. The method of claim 7, wherein the emissions comprise laser beams, and the reflections comprise reflections of the laser beams.

13. An apparatus comprising:

a transducer to receive plural reflections of corresponding emissions; and

a processor configured to

determine a threshold value based on a target reflection and received reflections determined to each result from a corresponding emission,

compare the target reflection to the threshold value, the target reflection comprising one of the plural reflections, and

determine if the target reflection is a reflection of a latest emission based on the comparison to the threshold value.

14. The apparatus of claim 13, wherein determining the threshold value comprises averaging magnitudes of the plural reflections.

15. The apparatus of claim 14, wherein determining the threshold value comprises applying a scaling factor to an average of the magnitudes of the plural reflections.

16. The apparatus of claim 13, wherein:

the plural reflections comprise a first reflection, followed by a second reflection, followed by a third reflection; and

the target reflection comprises the second reflection;

wherein the first reflection, the second reflection, and the third reflection are adjacent in time.

17. The apparatus of claim 13, wherein the emissions comprise sound waves and the plural reflections comprise echoes of the sound waves.

18. The apparatus of claim 13, wherein the emissions comprise laser beams, and the reflections comprise reflections of the laser beams.