Proximity sensing on mobile robots

• US 9,442,488 B2
• Filed: 05/16/2014
• Issued: 09/13/2016
• Est. Priority Date: 09/21/2012
• Status: Active Grant

• Current Assignee: iRobot Corporation
• Original Assignee: iRobot Corporation
• Inventors: Shamlian, Steven V., Duffley, Samuel, Romanov, Nikolai, Goel, Dhiraj, Hook, Frederic D., Munich, Mario E.
• Primary Examiner(s): Kiswanto, Nicholas
• Application Number:
  US14/279,598
• Publication Number:
  US 20140257622A1
• Time in Patent Office: 851 Days
• US Class Current: 1/1
• CPC Class Codes: G01B 11/026 by measuring distance between sensor and object G01B11/0608 takes precedence
• CPC Class Codes: G05D 1/0227 using mechanical sensing means, e.g. for sensing treated area
• 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 1/0242 using non-visible light signals, e.g. IR or UV signals
• CPC Class Codes: G05D 1/027 comprising intertial navigation means, e.g. azimuth detector inertial navigation G01C21/16; inertial navigation combined with non-inertial navigation instruments G01C21/165

Abstract

A proximity sensor includes first and second sensors disposed on a sensor body adjacent to one another. The first sensor is one of an emitter and a receiver. The second sensor is the other one of an emitter and a receiver. A third sensor is disposed adjacent the second sensor opposite the first sensor. The third sensor is an emitter if the first sensor is an emitter or a receiver if the first sensor is a receiver. Each sensor is positioned at an angle with respect to the other two sensors. Each sensor has a respective field of view. A first field of view intersects a second field of view defining a first volume that detects a floor surface within a first threshold distance. The second field of view intersects a third field of view defining a second volume that detects a floor surface within a second threshold distance.

Claims

1. A proximity sensor comprising:

a sensor body;

a first emitter housed by the sensor body;

a second emitter housed by the sensor body adjacent to the first emitter; and

a receiver disposed adjacent the first emitter opposite the second emitter;

wherein the first emitter has a first field of view, the second emitter has a second field of view, and the receiver has a third field of view; and

wherein an intersection of the first and third field of views defines a first volume and an intersection of the second and third fields of view defines a second volume, the first volume detecting a first surface within a first threshold distance from a sensing reference point and the second volume detecting a second surface within a second threshold distance from the sensing reference point, the second threshold distance being greater than the first threshold distance.

2. The proximity sensor of claim 1, wherein the first and second emitters and the receiver define a respective field of view axis and the sensor body defines a transverse axis and a longitudinal axis, the first and second emitters and the receiver are disposed along the transverse axis with their field of view axes arranged at an angle with respect to the longitudinal axis.

3. The proximity sensor of claim 2, wherein the field of view axes of the first and second emitters are parallel.

4. The proximity sensor of claim 2, wherein the field of view of one of the first and second emitters, and the receiver are arranged at an angle of between 0 and about 10 degrees with respect to the longitudinal axis of the sensor body.

5. The proximity sensor of claim 2, wherein the field of view of each of the first and second emitters is between about 5 degrees and about 15 degrees and the field of view of the receiver is greater than or equal to the field of views of the first and second emitters.

6. The proximity sensor of claim 1, wherein the sensor body comprises at least two baffles arranged to define the field of view of at least one of the first emitter, the second emitter, or the receiver.

7. The proximity sensor of claim 1, wherein the first threshold distance equals between about 1 inch and about 3 inches.

8. The proximity sensor of claim 1, wherein the second threshold distance is greater than 3 inches.

9. The proximity sensor of claim 1, wherein a first distance between the first emitter and the second emitter is greater than a second distance between the second emitter and the receiver.

10. The proximity sensor of claim 1, wherein the first volume of intersection extends approximately from the sensor body to about 5 cm from the sensor body, and the second volume of intersection extends from between about 3 cm to about 5 cm from the sensor body to a distance remote from the sensor body.

11. A method of sensing a proximity of an object, the method comprising:

receiving, at a computing processor, data from a first sensor comprising a first emitter and a first receiver;

receiving, at the computing processor, data from a second sensor comprising a second emitter and a second receiver, the first emitter and the second emitter being the same emitter or the first receiver and the second receiver being the same receiver;

determining, using the computing processor, based on the received data, a target distance between a sensing reference point and a sensed object;

determining, using the computing processor, if the target distance is within a first threshold distance or a second threshold distance; and

issuing a command, from the computing processor, based on whether the target distance is within the first threshold distance or the second threshold distance.

12. The method of claim 11, wherein a processing time of the computing processor between determining if the target distance is within a first or a second threshold distance and issuing a command is equal to or less than about 10 milliseconds.

13. The method of claim 11, wherein if the first emitter and the second emitter are the same, the method further comprises:

emitting light from the first emitter along a first field of view;

receiving reflections of the light at the first receiver along a second field of view;

receiving reflection of the light at the second receiver along a third field of view;

wherein the first field of view intersects the second and third fields of view, the intersection of the first and second fields of views defines a first volume and the intersection of the first and third fields of view defines a second volume, the first volume detecting a first surface within the first threshold distance from the sensing reference point and the second volume detecting a second surface within a second threshold distance from the sensing reference point, the second threshold distance being greater than the first threshold distance.

14. The method of claim 13, wherein the first, second, and third fields of view define first, second, and third field of view axes respectively, the second and the third field of view axes being parallel.

15. The method of claim 13, further comprising:

arranging a field of view axis defined by the first field of view at an angle between about 5 degrees and about 15 degrees with respect to a common longitudinal sensing axis; and

arranging field of view axes defined by the second and third fields of view at an angle of between 0 and about 10 degrees with respect to the common longitudinal sensing axis.

16. The method of claim 11, wherein if the first receiver and the second receiver are the same, the method further comprises:

receiving reflections of the light along a first field of view;

emitting light from the first emitter along a second field of view;

emitting light from the second emitter along a third field of view;

wherein the first field of view intersects the second and third fields of view, the intersection of the first and second fields of views defines a first volume and the intersection of the first and third fields of view defines a second volume, the first volume detecting a first surface within the first threshold distance from the sensing reference point and the second volume detecting a second surface within a second threshold distance from the sensing reference point, the second threshold distance being greater than the first threshold distance.

17. The method of claim 16, wherein the first, second, and third fields of view define first, second, and third field of view axes respectively, the second and the third field of view axes being parallel.

18. The method of claim 16, further comprising:

arranging a field of view axis defined by the first field of view at an angle between about 5 degrees and about 15 degrees with respect to a common longitudinal sensing axis; and

arranging field of view axes defined by the second and third fields of view at an angle of between 0 and about 10 degrees with respect to the common longitudinal sensing axis.

19. The method of claim 11, wherein a first distance between the first emitter and the first receiver is less than a second distance between the second emitter and the second receiver.

20. The method of claim 11, wherein the first threshold distance equals between about 1 inch and about 3 inches and/or the second threshold distance is greater than 3 inches.

21. An autonomous robot comprising:

a robot body defining a forward drive direction;

a drive system supporting the robot body and configured to maneuver the robot over a surface;

at least one proximity sensor comprising;

a first component having a first field of view;

a second component having a second field of view, the first field of view intersecting the second field of view to form a first volume of intersection; and

a third component having a third field of view, the first field of view intersecting the third field of view to form a second volume of intersection, the second volume of intersection being more distant from the robot body than the first volume of intersection and adjacent to the first volume of intersection,

wherein the first component is one of an emitter and a receiver, and each of the second component and third component is the remaining one of an emitter and a receiver; and

a controller in communication with the drive system and configured to;

incrementally or sequentially enable and disable each of the second and third components such that only one of the second and third components is enabled at one time; and

issue a drive command to the drive system to maneuver the robot based on a signal from the at least one proximity sensor generated when an object interferes with at least one of the first and second volumes of intersection.

22. The robot of claim 21, wherein the at least one proximity sensor further comprises a sensor body having at least two baffles arranged to define the field of view of at least one component, each component defining a field of view axis, and the sensor body defining a transverse axis and a longitudinal axis, the components disposed along the transverse axis with their field of view axes arranged at an angle with respect to the longitudinal axis.

23. The robot of claim 21, wherein the first volume of intersection extends approximately from the robot body to approximately 5 cm, and the second volume of intersection extends approximately from 3 to 5 cm from the robot body to a distance remote from the robot body.

24. The robot of claim 21, wherein a first distance between the first component and the second component is less than a second distance between the second component and the third component.

25. The robot of claim 24, wherein the field of view axes of the second component and the third component are not parallel.

26. The robot of claim 25, wherein the field of view axes of the and the third component are each arranged at an angle of between 0 and about 10 degrees with respect to the longitudinal axis defined by the sensor body towards a rearward portion of the robot body.

27. The robot of claim 24, wherein the field of view axis of the first component is arranged at an angle between about 5 degrees and about 15 degrees with respect to the longitudinal axis, the angle of the field of view axis of the first component being greater than the angles of the field of view axes of the second and third components.