Contact sensors for a mobile robot

• US 10,035,270 B2
• Filed: 11/11/2016
• Issued: 07/31/2018
• Est. Priority Date: 06/02/2015
• Status: Active Grant

• Current Assignee: iRobot Corporation
• Original Assignee: iRobot Corporation
• Inventors: Fay, Victor, Blitzblau, Seth, Duffley, Samuel, Dumont, Kyle, Woodman, Justin H.
• Primary Examiner(s): Kiswanto, Nicholas
• Application Number:
  US15/349,237
• Publication Number:
  US 20170072570A1
• Time in Patent Office: 627 Days
• 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 2201/04 Automatic control of the travelling movement; Automatic obstacle detection
• CPC Class Codes: A47L 9/009 Carrying-vehicles; Arrangements of trollies or wheels; Means for avoiding mechanical obstacles
• CPC Class Codes: B25J 13/085 Force or torque sensors B25J13/082, B25J13/084 take precedence
• CPC Class Codes: B25J 19/0075 Means for protecting the manipulator from its environment or vice versa
• CPC Class Codes: B25J 5/00 Manipulators mounted on wheels or on carriages B25J1/00 takes precedence; programme-controlled manipulators B25J9/00 ; vehicle aspects B60, B62, e.g. remote-controlled steering for motor vehicles B62D1/24; control of position of vehicles G05D1/00
• 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: G01D 5/142 using Hall-effect devices measuring magnetic variables using Hall-effect or other galvanomagnetic devices G01R33/06
• CPC Class Codes: G01D 5/20 by varying inductance, e.g. by a movable armature
• CPC Class Codes: G01D 5/2403 by moving plates, not forming part of the capacitor itself, e.g. shields
• CPC Class Codes: G01L 1/14 by measuring variations in capacitance or inductance of electrical elements, e.g. by measuring variations of frequency of electrical oscillators
• CPC Class Codes: G05D 1/0227 using mechanical sensing means, e.g. for sensing treated area
• CPC Class Codes: Y10S 901/01 Mobile robot

Abstract

A robot includes a body and a bumper. The body is movable relative to a surface and includes a first portion of a sensor. The bumper is mounted on the body and movable relative to the body and includes a backing and a second portion of the sensor. The backing is movable relative to the body in response to a force applied to the bumper. The second portion of the sensor is attached to the backing and movable with the backing relative to the first portion of the sensor in response to a force applied to the bumper. The sensor is configured to output an electrical signal in response to a movement of the backing. The electrical signal is proportional to an amount of displacement of the second portion relative to the first portion.

Claims

1. An autonomous mobile robot comprising:

a body movable relative to a surface;

a bumper mounted on the body and movable relative to the body, the bumper having a front side, a lateral side, and a corner, the bumper comprising;

a backing including a forward portion at the front side of the bumper, a lateral portion at the lateral side of the bumper, and a corner portion at the corner of the bumper, the corner portion connecting the forward portion and the lateral portion and being configured to inhibit a force applied to the forward portion of the backing from transferring to the lateral portion and to inhibit a force applied to the lateral portion of the backing from transferring to the forward portion;

a sensor system including a first sensor at the corner of the bumper to detect a force applied to the corner of the bumper; and

a controller operable to move the body based on an electrical signal from the sensor system.

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

a second sensor near the front side of the bumper to detect the force applied to the front side of the bumper, and

a third sensor near the lateral side of the bumper to detect the force applied to the lateral side of the bumper.

3. The robot of claim 2, wherein the controller is configured to

determine a location of a force applied to the bumper based on electrical signals of the first, second, and third sensors of the sensor system;

and

initiate moving of the body based on the location of the force.

4. The robot of claim 3, wherein the controller is configured to determine the location of the force applied to the bumper to be at the corner of the bumper based on an electrical signal from the third sensor being larger than an electrical signal from the first sensor and an electrical signal from the second sensor.

5. The robot of claim 3, wherein the electrical signals vary linearly with movement of the bumper.

6. The robot of claim 1, wherein an angle between the front side of the bumper and the lateral side of the bumper is between 75 and 105 degrees.

7. The robot of claim 1, wherein the bumper forms a partially frontally rectangular shape.

8. The robot of claim 1, wherein the backing comprises rigid regions interconnected by flexible regions to inhibit a force applied to the forward portion of the backing from transferring to the corner and to inhibit a force applied to the lateral portion of the backing from transferring to the corner portion.

9. The robot of claim 1, wherein the corner portion of the backing is thinner than the lateral portion of the backing and the forward portion of the backing.

10. The robot of claim 1, wherein:

the corner portion comprises a corner segment and a connecting segment connecting the corner segment to the lateral portion of the backing, the connecting segment having a length larger than a distance between the corner segment and the lateral portion so as to inhibit the force applied to the lateral side from transferring to the corner segment, and

the first sensor includes a portion attached to the corner segment of the backing.

11. The robot of claim 10, wherein the connecting segment is concave relative to a shape of the bumper.

12. The robot of claim 1, wherein:

the corner portion comprises a connecting segment connecting a corner segment to the forward portion, the connecting segment having a length larger than a distance between the corner segment and the forward portion so as to inhibit the force applied to the forward portion from transferring to the corner portion, and

the first sensor includes a portion attached to the corner segment of the backing.

13. The robot of claim 1, wherein the first sensor includes a first portion attached to the body and a second portion attached to the corner portion, the second portion of the first sensor being movable relative to the first portion of the first sensor to generate the electrical signal in response to contact between the corner of the bumper and an obstacle.

14. The robot of claim 1, wherein the first sensor comprises a capacitive sensor having a first plate attached to the body and a second plate attached to the backing.

15. The robot of claim 14, wherein at least one of the first plate or the second plate is non-planar.

16. The robot of claim 1, wherein the autonomous mobile robot is an autonomous cleaning robot configured to perform a cleaning operation on the surface.

17. The robot of claim 1, wherein the autonomous mobile robot is an autonomous cleaning robot configured to perform a cleaning operation on the surface.

18. An autonomous mobile robot comprising:

a body movable relative to a surface;

a bumper mounted on the body and vertically displaceable relative to the body;

a sensor system including a sensor having a first portion on the body and a second portion on the bumper, the sensor configured to

detect an obstacle in response to horizontal displacement of the second portion of the sensor relative to the first portion of the sensor when the bumper contacts the obstacle;

detect an overhead object in response to vertical displacement of the second portion of the sensor relative to the first portion of the sensor when the bumper contacts the overhead object; and

a controller operable to move the body based on an electrical signal from the sensor system to avoid the overhead object.

19. The robot of claim 18, wherein:

the sensor comprises a capacitive sensor;

the first portion comprises a first plate of the capacitive sensor;

the second portion comprises a second plate of the capacitive sensor; and

the electrical signal varies proportionally to an amount of displacement of the first plate relative to the second plate.

20. The robot of claim 19, wherein the electrical signal is indicative of a change in capacitance of the capacitive sensor, the change in capacitance varying with a vertical distance between the first plate and the second plate.

21. The robot of claim 18, wherein the second portion of the sensor is slidable relative to the first portion of the sensor, and the second portion of the sensor is displaceable toward or away from the first portion of the sensor.