Sonar system for remote vehicle

• US 8,989,947 B2
• Filed: 12/19/2012
• Issued: 03/24/2015
• Est. Priority Date: 09/07/2011
• Status: Active Grant

• Current Assignee: iRobot Corporation
• Original Assignee: iRobot Corporation
• Inventors: Wethern, Thomas James
• Primary Examiner(s): To, Tuan C.
• Assistant Examiner(s): SMITH, JELANI A
• Application Number:
  US13/719,726
• Publication Number:
  US 20140067186A1
• Time in Patent Office: 825 Days
• Field of Search: 700/245, 700/258, 701/23, 701/301, 701/46, 381/17, 381/337, 381/338, 381/339
• US Class Current: 701/26
• CPC Class Codes: G01S 15/003 Bistatic sonar systems; Multistatic sonar systems
• CPC Class Codes: G01S 15/931 of land vehicles
• CPC Class Codes: G01S 7/52003 Techniques for enhancing spatial resolution of targets G01S7/52046 takes precedence
• CPC Class Codes: G01S 7/521 Constructional features
• CPC Class Codes: G10K 11/02 Mechanical acoustic impedances; Impedance matching, e.g. by horns; Acoustic resonators
• CPC Class Codes: G10K 11/28 using reflection, e.g. parabolic reflectors

Abstract

A SONAR system for use with a robotic vacuum having SONAR emitters and receivers thereon. The SONAR system comprises a waveguide or horn located in front of the emitters and receivers that can improve the overall target resolution and reduce the number of “dead zones” where targets are not easily resolved.

Claims

1. A SONAR system for use with a remote vehicle, the SONAR system comprising:

at least one SONAR emitter having a waveguide tuned to guide emitted sound from the emitter into an environment of the remote vehicle; and

at least two SONAR receivers, each SONAR receiver having a waveguide tuned to receive reflected sound from an environment of the remote vehicle,

wherein each of the waveguides of the emitter and the receivers includes a front wall, a rear wall, a top wall, and a bottom wall, and at least one of the waveguides is tuned by varying a curvature of its front and rear walls and/or its top and bottom walls.

2. The SONAR system of claim 1, wherein the curvature of the rear wall of the emitter waveguide is not the same as the curvature of the front wall of the emitter waveguide.

3. The SONAR system of claim 1, wherein the curvature of the top wall of the emitter waveguide is not the same as the curvature of the bottom wall of the emitter waveguide.

4. The SONAR system of claim 1, wherein at least one of the waveguides is asymmetrical about its vertical axis.

5. The SONAR system of claim 1, wherein at least one of the waveguides is asymmetrical about its horizontal axis.

6. The SONAR system of claim 1, wherein the waveguides are configured to reduce near-field ground-plane reflections of signals emitted by the emitter to reduce a near-field Fresnel interference effect.

7. The SONAR system of claim 1, further comprising open-type PZT transducers.

8. The SONAR system of claim 1, further comprising closed-type PZT transducers.

9. The SONAR system of claim 1, further comprising mirror-bender PZT transducers.

10. The SONAR system of claim 1, further comprising piezoelectric film arrays arranged on a face of a bumper of the robotic vacuum.

11. The SONAR system of claim 1, wherein the emitter waveguide includes a mouth, and the system further comprises diverters placed in a center of an exit of the mouth of the emitter waveguide.

12. A SONAR system for use with a remote vehicle, the SONAR system comprising:

at least two SONAR emitters, each emitter having an emitter waveguide tuned to guide emitted sound from the emitter into an environment of the remote vehicle; and

at least two SONAR receivers, each SONAR receiver having a receiver waveguide tuned to receive reflected sound from an environment of the remote vehicle,

wherein the emitter waveguides are located and configured aim sound toward a target in the remote vehicle environment, each waveguide comprising a front wall, a rear wall, a top wall, and a bottom wall, at least one of the waveguides tuned by varying a curvature of its front and rear walls and/or its top and bottom walls.

13. The SONAR system of claim 12, wherein the emitters are located at outer edges of the remote vehicle.

14. The SONAR system of claim 12, wherein the emitter is located non-centrally on the remote vehicle and the emitter waveguides are tuned to guide signals from the emitters forward to better cover an area into which the remote vehicle is moving, directing the emitted signals toward difficult targets in a path of the remote vehicle from the greatest oblique angle possible while still being mounted on the remote vehicle.

15. A method for using a remote vehicle SONAR system to navigate a remote vehicle, the SONAR system comprising a first side-mounted emitter, a second side-mounted emitter, a central emitter, a first receiver located between the first side-mounted emitter and the central emitter, and a second receiver located between the second side-mounted emitter and the central emitter, the method comprising detecting obstacles by:

emitting a signal from the first side-mounted emitter;

listening for a reflection of the signal from the first side-mounted emitter with the first receiver;

firing the central emitter;

listening for a reflection of the signal from the central emitter with the first receiver and the second receiver;

firing the second side-mounted emitter; and

listening for a reflection of the signal from the second side-mounted emitter with the second receiver;

wherein each of the first side-mounted emitter, the second side-mounted emitter, and the central emitter have a waveguide tuned to guide emitted signals from their respective emitter into the environment of the remote vehicle, each of the first and second receivers having a waveguide tuned to receive reflected signals from the environment of the remote vehicle, and each waveguide comprising a front wall, a rear wall, a top wall, and a bottom wall, at least one of the waveguides tuned by varying a curvature of its front and rear walls and/or its top and bottom walls.

16. The method of claim 15, wherein the SONAR system further comprises a third receiver located between the first side-mounted emitter and the central emitter, and a fourth receiver located between the second side-mounted emitter and the central emitter, the method further comprising following a wall by:

emitting a signal from the first side-mounted emitter repetitively;

listening for a reflection of the signal from the first side-mounted emitter with the first receiver and the third receiver after each signal is emitted from the first side-mounted emitter;

using a differential between the signal received by the first receiver and the signal received by second receiver to determine whether the robotic vacuum is following the wall at a consistent spacing; and

controlling the remote vehicle steering to maintain a consistent spacing from a wall using the differential between the signal received by the first receiver and the signal received by second receiver.