WALL FOLLOWING ROBOT

• US 20160296092A1
• Filed: 04/09/2015
• Published: 10/13/2016
• Est. Priority Date: 04/09/2015
• Status: Active Grant

• Current Assignee: iRobot Corporation
• Original Assignee: iRobot Corporation
• Inventors: Wolfe, Brian, Lu, Ping-Hong
• Granted Patent: US 9,918,605 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A47L 11/28 Floor-scrubbing machines, motor-driven A47L11/29 takes precedence
• CPC Class Codes: A47L 11/4011 Regulation of the cleaning machine by electric means; Control systems and remote control systems therefor
• 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 11/4088 Supply pumps; Spraying devices; Supply conduits
• CPC Class Codes: A47L 2201/00 Robotic cleaning machines, i.e. with automatic control of the travelling movement or the cleaning operation
• CPC Class Codes: A47L 2201/04 Automatic control of the travelling movement; Automatic obstacle detection
• CPC Class Codes: A47L 2201/06 Control of the cleaning action for autonomous devices; Automatic detection of the surface condition before, during or after cleaning
• CPC Class Codes: A47L 9/00 Details or accessories of suction cleaners, e.g. mechanical means for controlling the suction or for effecting pulsating action; Storing devices specially adapted to suction cleaners or parts thereof; Carrying-vehicles specially adapted for suction cleaners
• CPC Class Codes: A47L 9/28 Installation of the electric equipment, e.g. adaptation or attachment to the suction cleaner; Controlling suction cleaners by electric means
• CPC Class Codes: A47L 9/2805 Parameters or conditions being sensed
• CPC Class Codes: G05D 1/0088 characterized by the autonomous decision making process, e.g. artificial intelligence, predefined behaviours using knowledge based models G06N5/00
• 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 1/0259 using magnetic or electromagnetic means
• CPC Class Codes: Y10S 901/01 Mobile robot

Abstract

An example robot includes a body that is movable relative to a surface, a bumper mounted on the body to enable movement of the bumper relative to the body, a sensor to produce a signal in response to the movement of the bumper relative to the body caused by contact between the bumper and the surface, and a controller to control movement of the body to cause the body to track the surface based on a value. The bumper is movable between an uncompressed position relative to the body and a compressed position relative to the body. The signal varies linearly with the movement of the bumper relative to the body. The value is based on the signal and indicates that the bumper in a partially compressed position has a compression range between the uncompressed position and the compressed position.

Claims

1. A robot comprising:

a body that is movable relative to a wall surface;

a bumper mounted on the body, the bumper being movable relative to the body within a range defined by an uncompressed position of the bumper and a compressed position of the bumper;

a sensor to produce a signal in response to movement of the bumper relative to the body; and

a controller to cause the robot to execute a wall following behavior in which the controller controls movement of the body to cause the body to track the wall surface while, based on the signal, causing the bumper to contact the wall surface at an angle such that the bumper is in a partially compressed position within the range between the uncompressed position and the compressed position.

2. The robot of claim 1, wherein the robot further comprises:

a cleaning pad attached to a bottom of the body; and

a fluid applicator configured to dispense fluid from the robot;

wherein configurations of the controller to cause the robot execute the wall following behavior comprise configurations in which the controller performs operations comprising;

controlling movement of the body to cause the body to contact the wall surface at the angle such that the bumper is in the partially compressed position; and

adjusting rotational and translational speeds of the robot to maintain the bumper in the partially compressed position.

3. The robot of claim 1, wherein configurations of the controller to cause the robot execute the wall following behavior comprise configurations to cause the robot to maintain contact with the wall surface such that the angle is between about 3 degrees and about 20 degrees.

4. The robot of claim 1, wherein the robot further includes:

a cleaning pad attached to a bottom of the body and extending beyond the bumper; and

a fluid applicator configured to dispense fluid from the robot;

wherein configurations of the controller to cause the robot execute the wall following behavior comprise configurations to cause the robot to maintain contact between the cleaning pad and the wall surface in the wall following behavior.

5. The robot of claim 1, wherein the sensor is a first sensor and the signal is a first signal, and wherein the robot further comprises:

a second sensor to produce a second signal in response to movement of the bumper, the second signal varying linearly with the movement of the bumper;

wherein the controller is configured to cause the bumper to contact the wall surface at the angle based on the first signal and the second signal.

6. The robot of claim 5, wherein the body has a left side, a right side, a front, and a back;

wherein the first sensor is adjacent to the right side and the second sensor is adjacent to the left side; and

wherein the bumper is located along the front of the robot and extends partially along the left side and the right side.

7. The robot of claim 6, further comprising:

a third sensor to produce a third signal in response to movement of the bumper, the third signal varying linearly with the movement of the bumper;

wherein the third sensor is between the left side and the right side, and wherein the third sensor is adjacent to the front.

8. The robot of claim 1, wherein the sensor comprises:

a post mounted to the bumper;

a magnet mounted to the post; and

a Hall Effect sensor mounted in the body above the magnet.

9. The robot of claim 1, wherein the sensor comprises a capacitive sensor, the capacitive sensor comprising a pair of capacitive plates, at least one of the capacitive plates being movable relative to another of the capacitive plates based on movement of the bumper;

and

wherein the controller is programmed to determine a time constant from signals produced in response to movement of the at least one capacitive plate.

10. The robot of claim 1, wherein the sensor comprises an inductive sensor, the inductive sensor comprising a core material that is movable within windings based on movement of the bumper;

and

wherein the controller is programmed to determine a time constant from signals in response to movement of the core material.

11. The robot of claim 1, wherein the controller is programmed to control movement of the body to track the wall surface to maintain contact with the wall surface by maintaining a value within a compression range, the value being based on the signal and indicative of the bumper being compressed by an amount of compression associated with the compression range.

12. The robot of claim 1, wherein the controller is programmed to dynamically calibrate a position of the bumper relative to the body in response to the bumper being within a predefined range of the uncompressed position.

13. The robot of claim 1, wherein the controller is further programmed to control movement of the body to cause the body to retreat from the wall surface in response to a value being outside a compression range, the value being based on the signal and indicative of the bumper being compressed further than an amount of compression associated with the compression range.

14. The robot of claim 1, wherein the controller is further programmed to control movement of the body to cause the body to turn toward the surface in response to a value being outside a compression range, the value being based on the signal and indicative of the bumper being compressed less than an amount of compression associated with the compression range.

15. The robot of claim 1, wherein:

the body comprises wheels;

the robot further comprises detectors associated with the wheels, the detectors for detecting speed of the wheels; and

the controller is programmed to control movement of the body to cause the body to retreat from the wall surface, to turn-away from the wall surface, and then to re-engage the wall surface based, at least in part, on the speed of the wheels being less than a predetermined speed and a value being outside a compression range.

16. The robot of claim 1, further comprising:

a cleaning pad attached to a bottom of the body, the cleaning pad extending beyond the bumper.

17. (canceled)

18. A robot comprising:

a body that is movable relative to a wall surface;

a bumper mounted on the body;

linear sensors to produce signals in response to movement of the bumper relative to the body caused by contact between the bumper and the wall surface over a period of time, the signals varying linearly with movement of the bumper; and

a controller to cause the robot to execute a wall following behavior in which the controller controls movement of the body to track the wall surface while maintaining a difference between the signals at least during the period of time.

19. The robot of claim 18, wherein the robot further comprises:

a cleaning pad attached to a bottom of the body; and

a fluid applicator configured to dispense fluid from the robot;

wherein configurations of the controller to cause the robot to execute the wall following behavior comprise configurations in which the controller performs operations comprising;

controlling movement of the body to cause the body to contact the wall surface at an angle such that the bumper is in a partially compressed position; and

adjusting rotational and translational speeds of the robot to maintain compression of the bumper in the partially compressed position.

20. The robot of claim 18, wherein:

configurations of the controller to cause the robot to execute the wall following behavior comprise configurations to cause the robot to maintain contact with the wall surface at an angle of between about 3 degrees and about 20 degrees.

21. The robot of claim 18, wherein the robot further includes:

a cleaning pad attached to a bottom of the body and extending beyond the bumper; and

a fluid applicator configured to dispense fluid from the robot;

wherein configurations of the controller to cause the robot to execute the wall following behavior comprise configurations to cause the robot to maintain contact between the cleaning pad and the wall surface in the wall following behavior.

22. The robot of claim 18, wherein the linear sensors comprise a first linear sensor and a second linear sensor, the first linear sensor being disposed adjacent to a first side of the body and the second linear sensor being disposed adjacent to second side of the body.

23. The robot of claim 22, wherein the linear sensors comprise a third linear sensor disposed between the first linear sensor and the second linear sensor.

24. The robot of claim 18, wherein each linear sensor comprises:

a post mounted to the bumper;

a magnet mounted to the post; and

a Hall Effect sensor mounted in the body above the magnet.

25. The robot of claim 18, wherein each linear sensor comprises a capacitive sensor, each capacitive sensor comprising a pair of capacitive plates, at least one of the capacitive plates being movable relative to another of the capacitive plates based on movement of the bumper;

and

wherein the controller is programmed to determine a time constant from signals produced in response to movement of the at least one capacitive plate.

26. The robot of claim 18, wherein each linear sensor comprises an inductive sensor, the inductive sensor comprising a core material that is movable within windings based on movement of the bumper;

and

wherein the controller is programmed to determine a time constant from signals in response to movement of the core material.

27. A method of controlling a robot, comprising:

detecting, based on at least one signal that varies linearly with an amount of force between the robot and a wall surface, a level of contact between the robot and the wall surface; and

,

based on a threshold being exceeded by a value of the at least one signal, maintaining an angle between the wall surface and the robot during a wall following behavior.

28. The method of claim 27, wherein the threshold is a lower threshold, and wherein the method further comprises:

determining, based on the at least one signal, that the value of the at least one signal exceeds an upper threshold, the upper threshold being greater than the lower threshold; and

in response to determining that the value exceeds the upper threshold, controlling the robot to retreat from the wall surface.

29. The method of claim 27, wherein the robot comprises wheels, and wherein the method further comprises:

detecting a speed of the wheels; and

based at least in part on the speed of the wheels, controlling the robot to retreat from the wall surface, to turn-away from the surface, and then to re-engage the wall surface.

30. The method of claim 27, wherein the detecting is based on two or more signals that vary linearly with the amount of force between the robot and the wall surface, and the maintaining comprises maintaining the angle between the robot and the wall surface based at least in part on the two or more signals.

31. The method of claim 27, wherein the maintaining the angle between the wall surface and the robot comprises maintaining a bumper of the robot in a partially compressed position within a range defined by a compressed position of the bumper and an uncompressed position of the bumper.