Obstacle Following Sensor Scheme For A Mobile Robot

• US 20090292393A1
• Filed: 06/18/2009
• Published: 11/26/2009
• Est. Priority Date: 01/24/2000
• Status: Active Grant

• Current Assignee: iRobot Corporation
• Original Assignee: iRobot Corporation
• Inventors: Ozick, Daniel N., Cross, Matthew, Jones, Joseph L., Casey, Christopher
• Granted Patent: US 8,565,920 B2
• Time in Patent Office: Days
• US Class Current: 700/245
• CPC Class Codes: A47L 2201/04 Automatic control of the travelling movement; Automatic obstacle detection
• CPC Class Codes: B25J 9/1697 Vision controlled systems
• CPC Class Codes: G01S 15/931 of land vehicles
• CPC Class Codes: G01S 17/93 for anti-collision purposes
• CPC Class Codes: G05D 1/0238 using obstacle or wall sensors G05D1/0246 and G05D1/0289 take precedence; lidar systems designed for anti-collision purposes G01S17/93
• CPC Class Codes: G05D 1/024 in combination with a laser lasers per se H01S
• 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 2201/0203 Cleaning or polishing vehicle
• CPC Class Codes: G05D 2201/0208 Lawn mower
• CPC Class Codes: G05D 2201/0215 Vacuum cleaner
• CPC Class Codes: Y02P 90/02 Total factory control, e.g. smart factories, flexible manufacturing systems [FMS] or integrated manufacturing systems [IMS]
• CPC Class Codes: Y10S 901/01 Mobile robot
• CPC Class Codes: Y10S 901/47 Optical

Abstract

A robot obstacle detection system including a robot housing which navigates with respect to a surface and a sensor subsystem aimed at the surface for detecting the surface. The sensor subsystem includes an emitter which emits a signal having a field of emission and a photon detector having a field of view which intersects the field of emission at a region. The subsystem detects the presence of an object proximate the mobile robot and determines a value of a signal corresponding to the object. It compares the value to a predetermined value, moves the mobile robot in response to the comparison, and updates the predetermined value upon the occurrence of an event.

Claims

1-33. -33. (canceled)

34. 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 objects near a lateral side of the robot; and

a drive controller that controls the drive mechanism to drive the robot to follow a sensed object proximate the lateral side of the robot, the drive controller configured to monitor the sensor to detect when a followed object is no longer proximate the lateral side of the robot, to initiate a turn of the robot toward the lateral side in accordance with a turning radius in response to detecting that the followed object is no longer proximate the lateral side, and then to progressively decrease the turning radius of the robot over time while driving the robot forward, thereby causing the robot to turn more sharply until the robot encounters a change in sensory input.

35. The mobile robot of claim 34, wherein the controller is configured to steadily decrease the turning radius at least until the robot bumps an object.

36. The mobile robot of claim 34, wherein the sensor is a reflection detector, and wherein the controller detects that the followed object is no longer proximate the lateral side upon a transition from a reflection state to a non-reflection state of the sensor.

37. The mobile robot of claim 34, wherein the controller is configured to decrease the turning radius of the robot until the sensor detects an object on the lateral side.

38. The mobile robot of claim 34, further comprising a floor cleaner disposed on the lateral side of the robot.

39. The mobile robot of claim 38, wherein the floor cleaner 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.

40. The mobile robot of claim 34, 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.

41. The mobile robot of claim 40, 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.

42. The mobile robot of claim 41, 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.

43. The mobile robot of claim 41, further comprising a bump sensor, and wherein the first angle is determined according to an angle at which the bump sensor indicates a bump.

44. A mobile robot, comprising:

a drive mechanism that both drives the robot forward across a floor 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 cleaner disposed on the lateral side of the robot; and

a drive controller that controls the drive mechanism to turn the robot to follow the object on the lateral side of the robot, by changing a robot turning radius to maintain continuous detection of the object by the sensor, including turning the robot toward the lateral side while decreasing the robot turning radius in response to cessation of detection of the object proximate the lateral side.

45. The mobile robot of claim 44, wherein the controller sets an initial turning radius and steadily decreases the turning radius until the robot bumps against an object.

46. The mobile robot of claim 44, wherein the controller controls the drive mechanism to follow a path having a turning radius proportional to an angle of turn.

47. The mobile robot of claim 44, wherein the sensor is a reflection detector, and wherein the controller determines cessation of detection of the object upon the sensor transitioning from a reflection state to a non-reflection state.

48. The mobile robot of claim 44, wherein the controller decreases the robot turning radius until the sensor detects an object on the lateral side.

49. The mobile robot of claim 44, wherein the floor area cleaner comprises 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 housing for collection by the robot.

50. The mobile robot of claim 44, wherein the sensor is responsive to proximity of a room wall, and wherein the controller drives the robot to follow a proximate wall on the lateral side of the robot by changing a turning radius to maintain continuous detection of the wall by the sensor, including turning the robot toward the lateral side while decreasing the turning radius of the robot in response to cessation of detection of the wall proximate the lateral side

51. 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 proximity 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, the drive controller configured to monitor the sensor to detect when the wall is no longer proximate the lateral side of the robot, in response to detecting that the wall is no longer proximate the lateral side, initiate a turn of the robot toward the lateral side in accordance with a turning radius in response to detecting that the followed wall is no longer proximate the lateral side, and then progressively decrease the turning radius of the robot over time while driving the robot forward, thereby causing the robot to turn more sharply until one of the sensors detects a wall on the lateral side.