Method and system for multi-mode coverage for an autonomous robot

• US 9,327,407 B2
• Filed: 07/07/2015
• Issued: 05/03/2016
• Est. Priority Date: 06/12/2001
• Status: Expired due to Term

• Current Assignee: iRobot Corporation
• Original Assignee: iRobot Corporation
• Inventors: Jones, Joseph L., Mass, Philip R.
• Primary Examiner(s): Black, Thomas G
• Assistant Examiner(s): LEWANDROSKI, SARA J
• Application Number:
  US14/793,224
• Publication Number:
  US 20150306772A1
• Time in Patent Office: 301 Days
• Field of Search: 700/253, 700/258, 700/250, 700/245, 700/246, 700/255, 701/301, 701/23, 701/527, 701/498, 701/519, 153/19
• US Class Current: 1/1
• CPC Class Codes: A47L 11/00 Machines for cleaning floors, carpets, furniture, walls, or wall coverings
• CPC Class Codes: B25J 11/0085 Cleaning
• CPC Class Codes: B25J 9/1694 characterised by use of sensors other than normal servo-feedback from position, speed or acceleration sensors, perception control, multi-sensor controlled systems, sensor fusion
• CPC Class Codes: G05D 1/0219 ensuring the processing of the whole working surface
• CPC Class Codes: G05D 1/0227 using mechanical sensing means, e.g. for sensing treated area
• CPC Class Codes: G05D 1/0242 using non-visible light signals, e.g. IR or UV signals
• CPC Class Codes: G05D 1/0255 using acoustic signals, e.g. ultra-sonic singals sonar systems designed for anti-collision purposes G01S15/93
• CPC Class Codes: G05D 1/0272 comprising means for registering the travel distance, e.g. revolutions of wheels measuring distance traversed on the ground by vehicles, e.g. using odometers G01C22/00
• CPC Class Codes: Y10S 901/01 Mobile robot

Abstract

A control system for a mobile robot (10) is provided to effectively cover a given area by operating in a plurality of modes, including an obstacle following mode (51) and a random bounce mode (49). In other embodiments, spot coverage, such as spiraling (45), or other modes are also used to increase effectiveness. In addition, a behavior based architecture is used to implement the control system, and various escape behaviors are used to ensure full coverage.

Claims

1. A mobile robot comprising:

drive wheels operable to move the robot over a surface;

an obstacle detection sensor; and

a control system operatively connected to the obstacle detection sensor and to the drive wheels;

wherein said control system is configured to;

operate the robot in a plurality of modes including both an obstacle following mode in which the robot travels adjacent to an encountered obstacle, and a bounce mode in which the robot travels away from an encountered obstacle;

track a frequency of obstacle encounters; and

to operate the robot in the obstacle following mode over a distance determined as a function of the tracked frequency of obstacle encounters.

2. A mobile robot according to claim 1, wherein the tactile sensor comprises a bumper switch disposed along a forward edge of the robot.

3. A mobile robot according to claim 1, wherein the frequency of obstacle encounters is a function of obstacle encounters detected by sensors of the robot other than the obstacle detection sensor.

4. A mobile robot according to claim 1, wherein the control system is configured to track the frequency of obstacle encounters while operating the robot in a mode other than the obstacle following mode.

5. A mobile robot according to claim 1, wherein the control system is configured to switch into the bounce mode in response to the robot traveling a predetermined distance without encountering an obstacle.

6. A mobile robot according to claim 5, wherein the predetermined distance is at least 115 centimeters.

7. A mobile robot according to claim 1, wherein, in the obstacle following mode, the robot follows the obstacle for a distance at least twice a working width of the robot.

8. A mobile robot according to claim 1, wherein the tracked frequency of obstacle encounters is a function of the approximate area of the surface.

9. A mobile robot according to claim 1, wherein the tracked frequency of obstacle encounters is a function of time or distance traveled.

10. A mobile robot according to claim 1, wherein the control system is configured to switch between operational modes as a function of the tracked frequency of obstacle encounters.

11. A mobile robot according to claim 1, wherein the control system alternates between operational modes in response to a lack of sensor input.

12. A mobile robot according to claim 1, further comprising a cliff detector, and wherein the control system is configured to reduce velocity of the robot in response to detection of a cliff.

13. A mobile robot according to claim 1, further comprising a wheel drop sensor operatively coupled to the control system, and wherein the control system is configured to operate the robot as a function of input from the wheel drop sensor.

14. A mobile robot according to claim 1, wherein the obstacle detection sensor comprises a tactile sensor responsive to a bump event between the robot and an object.