Mobile Robot Area Cleaning

• US 20160103451A1
• Filed: 10/10/2014
• Published: 04/14/2016
• Est. Priority Date: 10/10/2014
• Status: Active Grant

• Current Assignee: iRobot Corporation
• Original Assignee: iRobot Corporation
• Inventors: Vicenti, Jasper
• Granted Patent: US 9,798,328 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A47L 11/4061 Steering means; Means for avoiding obstacles; Details related to the place where the driver is accommodated
• CPC Class Codes: A47L 11/4066 Propulsion of the whole machine
• CPC Class Codes: A47L 2201/04 Automatic control of the travelling movement; Automatic obstacle detection
• CPC Class Codes: B25J 11/0085 Cleaning
• CPC Class Codes: G05D 1/0242 using non-visible light signals, e.g. IR or UV signals

Abstract

A cleaning robot includes a chassis, a drive system connected to the chassis and configured to drive the robot, a signal generator and sensor carried by the chassis, and a controller in communication with the drive system and the sensor. The signal generator directs a signal toward the floor surface. The sensor is responsive to reflected signals from the floor surface. The controller controls the drive system to alter direction of the robot responsive to a reflected signal indicating an edge of the floor surface.

Claims

1. A cleaning robot comprising:

a chassis;

a drive system connected to the chassis and configured to drive the robot across a floor surface;

a signal generator carried by the chassis and arranged to direct a signal toward the floor surface;

a sensor carried by the chassis and responsive to a reflection of the directed signal from the floor surface; and

a controller in communication with the drive system and the sensor, the controller configured to control the drive system to alter direction of the robot in response to the sensor receiving a reflected signal indicating an edge of the floor surface, so as to keep the robot from crossing the floor surface edge.

2. The cleaning robot of claim 1, wherein the controller is configured to redirect the robot in response to a reflected signal indicating an edge of an area rug on which the robot is moving, the reflected signal indicating a reflection from a floor adjacent the edge of the area rug.

3. The cleaning robot of claim 1, further comprising multiple associated pairs of signal generators and sensors disposed at different locations about a peripheral edge of the robot, and wherein the controller is configured to alter robot direction as a function of which sensor receives a reflected signal indicating a floor surface edge.

4. The cleaning robot of claim 1, wherein the sensor is responsive to a characteristic of the reflected signal indicating an elevation of the floor surface.

5. The cleaning robot of claim 1, wherein the sensor is responsive to a characteristic of the reflected signal indicating a reflectivity of the floor surface.

6. The cleaning robot of claim 1, wherein the sensor is responsive to a characteristic of the reflected signal indicating floor surface roughness.

7. The cleaning robot of claim 1, wherein the signal generator is configured to emit an infrared signal and wherein the sensor is responsive to a reflection of the infrared signal from the floor surface.

8. The cleaning robot of claim 1, wherein the controller is further configured to control the drive system to drive the robot across the edge of the floor surface in a predetermined set of circumstances.

9. The cleaning robot of claim 1, wherein the controller is further configured to redirect the robot away from a cliff edge sensed by an absence of a reflected signal at the sensor.

10. A method of maneuvering an autonomous robot across a floor within a bounded area having at least one open edge, the method comprising:

driving the robot across the floor while sensing a signal from the robot reflected by the floor and received at a sensor carried by the robot;

while continuing to drive the robot, evaluating the reflected signal to determine whether a characteristic of the received reflected signal indicates that the robot is adjacent an open edge of the bounded area; and

,

in response to determining from the reflected signal that the robot is adjacent an open edge of the bounded area, altering a direction of robot motion such that the robot is directed away from the open edge.

11. The method of claim 10, wherein evaluating the reflected signal comprises evaluating the reflected signal against a baseline signal characteristic to sense a change in floor surface roughness.

12. The method of claim 10, wherein the bounded area is the area of a rug having a perimeter edge adjacent a surrounding floor surface, and wherein the robot motion direction is altered in response to the sensor receiving a reflected signal indicating reflection from a surface other than a surface of the rug.

13. The method of claim 10, wherein the bounded area is a carpeted area, wherein the open edge is adjacent an uncarpeted floor surface, and wherein the robot motion direction is altered in response to the sensor receiving a reflected signal indicating reflection from the uncarpeted floor surface.

14. The method of claim 10, wherein evaluating the reflected signal comprises comparing the reflected signal to a stored baseline signal.

15. The method of claim 14, wherein the sensor is one of multiple sensors disposed at different places about a periphery of the robot, and wherein the reflected signal data is evaluated separately for each of the multiple sensors.

16. The method of claim 15, wherein the robot motion is altered as a function of which of multiple reflected signals differs greatest from the stored baseline signal.

17. The method of claim 15, wherein the robot motion is altered to navigate a corner of the bounded area in response to changes in reflected signal at sensors located on opposite sides of the robot.

18. The method of claim 14, wherein the sensor is responsive to a characteristic of the reflected signal indicating a reflectivity of a surface of the floor.

19. The method of claim 14, wherein the robot further comprises a signal emitter configured to emit an infrared signal, and wherein the sensor is responsive to a reflection of the infrared signal from the floor.

20. The method of claim 10, further comprising, in response to sensing a loss of reflected signal above a predetermined signal threshold value at the sensor, redirecting the robot away from a side of the floor location corresponding to sensor location at the loss of reflected signal.

21. The method of claim 10, further comprising, upon determining from the reflected signal that the robot is adjacent an open edge of the bounded area following a triggering event, driving the robot across the open edge.