Method and System for Multi-Mode Coverage For An Autonomous Robot

• US 20070213892A1
• Filed: 02/05/2007
• Published: 09/13/2007
• Est. Priority Date: 06/12/2001
• Status: Active Grant

• Current Assignee: iRobot Corporation
• Original Assignee: iRobot Corporation
• Inventors: Jones, Joseph, Mass, Philip
• Granted Patent: US 8,396,592 B2
• Time in Patent Office: Days
• US Class Current: 701/23
• 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: G05D 2201/0203 Cleaning or polishing vehicle
• 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

1-2. -2. (canceled)

3. A mobile robot, comprising:

a drive mechanism that both drives the robot forward in a drive direction and turns the robot to change the drive direction;

a sensor responsive to proximity of an object to be followed on a lateral side of the robot;

a floor area cleaning mechanism disposed on the lateral side of the robot; and

a drive controller that controls the drive mechanism to follow the object on the lateral side of the robot, by

monitoring the sensor to detect when the object is no longer proximate the lateral side of the robot; and

,

in response to detecting that the object is no longer proximate the lateral side, turning the robot toward the lateral side while decreasing a turning radius of the robot.

4. The mobile robot of claim 3, wherein the controller is configured to set an initial turning radius and to steadily decrease the turning radius at least until the robot bumps an object.

5. The mobile robot of claim 3, wherein the sensor is a reflection detector, and wherein controller detects that the object is not present upon a transition from a reflection state to a non-reflection state of the sensor.

6. The mobile robot of claim 3, wherein the controller decreases the turning radius of the robot until the sensor detects an object on the lateral side.

7. The mobile robot of claim 3, wherein the floor area cleaning mechanism includes a side brush extending beyond a lateral extent of a housing of the robot, the side brush driven to sweep debris from a floor surface beyond the lateral extent of the housing, for collection by the robot.

8. The mobile robot of claim 3, wherein

the sensor is responsive to proximity of a room wall;

and

the controller is configured to

drive the robot to follow a proximate wall on the lateral side of the robot by changing a turning radius to maintain a continuous detection of the wall by the sensor,

monitor the sensor to detect when the wall is no longer proximate the lateral side of the robot, and

in response to detecting that the wall is no longer proximate the lateral side, turning the robot toward the lateral side while decreasing the turning radius of the robot.

9. The mobile robot of claim 8, wherein the controller is configured to, in response to the robot bumping into an object while following a wall,

turn the robot through a first angle, then monitor the sensor for wall detection while continuing to turn the robot, and then,

in response to wall detection and a subsequent cessation of wall detection, stop turning the robot.

10. The mobile robot of claim 9, wherein the controller is configured to stop turning the robot if the robot reaches a predetermined maximum turn angle while monitoring the sensor for wall detection, and to then move the robot forward along the drive direction.

11. The mobile robot according to claim 9 further comprising a bump sensor, and wherein the first angle is determined according to an angle at which the bump sensor indicates a bump.

12. A mobile robot, comprising:

a drive mechanism that both drives the robot forward in a drive direction and turns the robot to change the drive direction;

a forward obstacle sensor responsive to objects encountered by the robot while moving in the drive direction;

a side sensor positioned to detect proximity of objects on a dominant side of the robot, transverse to the drive direction;

a floor area cleaning mechanism disposed on the dominant side of the robot; and

a drive controller that controls the drive mechanism to turn the robot, in response to detection of an object by the forward obstacle sensor, until proximity of the detected object on the dominant side of the robot is indicated by the side sensor, and then to drive the robot in the drive direction.

13. The mobile robot of claim 12, wherein the drive controller is further configured to drive the robot, in response to indication of object proximity on the dominant side of the robot, so as to keep the detected object on the dominant side of the robot.

14. The mobile robot of claim 12, wherein the floor area cleaning mechanism includes a side brush extending beyond a lateral extent of a housing of the robot on the dominant, the side brush arranged to sweep debris from beyond a perimeter of the robot for collection by the robot.

15. The mobile robot of claim 14, wherein forward obstacle sensor and the side sensor are both responsive to walls, and wherein the drive controller, in response to the forward sensor detecting a wall in the drive direction, turns the robot until the detected wall is detected on the dominant side of the robot, and then drives the robot to keep the detected wall on the dominant side of the robot.

16. The mobile robot of claim 12, wherein the drive controller is further configured to

drive the robot to follow an object detected on the dominant side of the robot, by changing a turning radius to maintain detection of the object by the side sensor;

and

upon detecting that the object is no longer proximate the dominant side of the robot, to turn the robot toward the dominant side of the robot while decreasing a turning radius of the robot.

17. The robot of claim 12, wherein the drive controller determines that an object is no longer proximate the dominant side of the robot upon transition of the side sensor from a reflection state to a non-reflection state.

18. The mobile robot of claim 12, wherein the drive controller is configured to drive the robot to turn in a spiral having a steadily increasing radius, such that the dominant side of the robot is positioned on an outward edge of the spiral.

19. The mobile robot of claim 12 further comprising a bump sensor responsive to the robot bumping into an object in the drive direction, and wherein the drive controller, in response to the robot bumping into an object in the drive direction while the robot is following an object on the dominant side, turns the robot away from the dominant side through a first angle, stops turning the robot when the side sensor detects the bumped object, and then drives the robot forward in the drive direction, such that the robot tends to travel along the bumped object.

20. The mobile robot of claim 19, wherein the drive controller, in response to turning the robot away from the dominant side through a second angle, larger than the first angle, without detecting the bumped object with the side sensor, stops turning the robot and then drives the robot forward in the drive direction.

21. A mobile robot, comprising:

a robot housing;

a drive mechanism that both drives the robot housing forward in a drive direction and turns the robot housing to change the drive direction;

a bump sensor responsive to the robot bumping into an object in the drive direction;

a sensor responsive to proximity of a wall to be followed on a lateral side of the robot housing;

a side brush extending beyond a lateral extent of the housing, the side brush driven to sweep debris from a floor surface beyond the lateral extent of the housing, for collection by the robot; and

a drive controller that controls the drive mechanism to follow the wall on the lateral side of the robot, by

monitoring the sensor to detect when the wall is no longer proximate the lateral side of the robot; and

in response to detecting that the wall is no longer proximate the lateral side, turning the robot toward the lateral side while decreasing a turning radius of the robot until the sensor detects a wall on the lateral side.