Autonomous mobile robot

• US 7,539,557 B2
• Filed: 12/30/2006
• Issued: 05/26/2009
• Est. Priority Date: 12/30/2005
• Status: Expired due to Fees

• Current Assignee: iRobot Corporation
• Original Assignee: iRobot Corporation
• Inventors: Yamauchi, Brian
• Primary Examiner(s): Tran; Khoi H.
• Assistant Examiner(s): Marc; McDieunel
• Application Number:
  US11/618,742
• Publication Number:
  US 20070156286A1
• Time in Patent Office: 878 Days
• Field of Search: 700/245, 700/246, 700/258, 700/259, 700/262, 701/2, 701/45, 701/46, 701/301, 340/5.71, 340/825.72, 340/937, 382/103, 382/104, 348/149
• US Class Current: 700/245
• CPC Class Codes: G05D 1/0038 by providing the operator with simple or augmented images from one or more cameras located onboard the vehicle, e.g. tele-operation images analyzed by a computer and used for automatic navigation G05D1/0246
• CPC Class Codes: G05D 1/0044 by providing the operator with a computer generated representation of the environment of the vehicle, e.g. virtual reality, maps maps used for automatic navigation G05D1/0274; flight directors G01C23/005
• 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 1/024 in combination with a laser lasers per se H01S
• CPC Class Codes: G05D 1/0251 extracting 3D information from a plurality of images taken from different locations, e.g. stereo vision stereoscopic image analysis H04N13/00; depth recovery from images G06T7/593
• 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
• CPC Class Codes: G05D 1/0278 using satellite positioning signals, e.g. GPS

Abstract

A mobile robot is equipped with a range finder and a stereo vision system. The mobile robot is capable of autonomously navigating through urban terrain, generating a map based on data from the range finder and transmitting the map to the operator, as part of several reconnaissance operations selectable by the operator. The mobile robot employs a Hough transform technique to identify linear features in its environment, and then aligns itself with the identified linear features in order to navigate through the urban terrain; while at the same time, a scaled vector field histogram technique is applied to the combination of range finder and stereo vision data to detect and avoid obstacles the mobile robot encounters when navigating autonomously. Also, the missions performed by the mobile robot may include limitation parameters based on distance or time elapsed, to ensure completion of the autonomous operations.

Claims

1. A mobile robot for autonomously performing reconnaissance, comprising:

a drive system configured to propel the mobile robot across terrain;

a range sensor configured to detect a distance between the mobile robot and one or more objects in an environment of the mobile robot;

a position reckoner including one or more of the group consisting of a global positioning satellite receiver, an odometer, or an inertial navigation system;

a processor communicatively connected to the range sensor, to the position reckoner, and to the drive system, and configured to execute software instructions; and

a memory store communicatively connected to the processor, the memory store having stored thereon a plurality of software instructions configured to be executed by the processor, the software instructions including;

a mapping routine configured to maintain an occupancy grid map of the environment of the mobile robot,

a linear feature routine configured to detect one or more linear patterns in the occupancy grid map and to determine a strongest line among the one or more linear patterns,

a navigational routine configured to control the drive system to move the mobile robot in a direction aligned with the strongest line among the one or more linear patterns, and

a localization routine configured to update the occupancy grid map using a scaled vector field histogram based on input from the range sensor and the position reckoner integrated using a Kalman filter with a motion model corresponding to the mobile robot.

2. The mobile robot reconnaissance system according to claim 1, wherein the software instructions stored by the memory store further include a perimeter-following routine corresponding to a perimeter-following mission,

wherein the perimeter-following routine, when executed by the processor, is configured to cause the mobile robot to circumnavigate a reconnaissance target identified using a Hough transform, to record the occupancy grid map when circumnavigating the reconnaissance target, and to transmit the recorded occupancy grid map to the teleoperation console in the teleoperation mode.

3. The mobile robot reconnaissance system according to claim 1, wherein the software instructions stored in the memory store further include a street-following routine corresponding to a street-following robot mission,

wherein the street-following routine, when executed by the processor, is configured to cause the mobile robot to navigate to a first location selected by the operator in the teleoperation mode, to identify a street using a scaled vector field histogram in the autonomous mode, to traverse the identified street to a specified distance from the initial location in the autonomous mode, to record the occupancy grid map when traversing the identified street in the autonomous mode, to return to the first location in the autonomous mode, and to transmit the recorded occupancy grid map to the teleoperation console in the teleoperation mode.

4. The mobile robot reconnaissance system according to claim 1, wherein the mobile robot further includes an operator interface disposed on the mobile robot and configured to be operated by the operator,

wherein the mobile robot is further configured to perform at least one of the robot missions in the autonomous mode starting from an initial location of the mobile robot when the operator interface is operated.

5. A mobile robot for autonomously performing reconnaissance, comprising:

a drive system configured to propel the mobile robot across terrain;

a range sensor configured to detect a distance between the mobile robot and one or more objects in an environment of the mobile robot;

a processor communicatively connected to the range sensor and to the drive system, and configured to execute software instructions; and

a memory store communicatively connected to the processor, the memory store having stored thereon a plurality of software instructions configured to be executed by the processor, the software instructions including;

a mapping routine configured to maintain an occupancy grid map of the environment of the mobile robot,

a linear feature routine configured to detect one or more linear patterns in the occupancy grid map and to determine a strongest line among the one or more linear patterns, and

a navigational routine configured to control the drive system to move the mobile robot in a direction aligned with the strongest line among the one or more linear patterns,

wherein a location of the mobile robot when the mapping routine begins maintaining the occupancy grid map is designated as an initial location, and

wherein the navigational routine prevents the drive system from moving the mobile robot farther than 250 meters from the initial location.

6. The mobile robot reconnaissance system according to claim 5, wherein the software instructions stored by the memory store further include a perimeter-following routine corresponding to a perimeter-following mission,

wherein the perimeter-following routine, when executed by the processor, is configured to cause the mobile robot to circumnavigate a reconnaissance target identified using a Hough transform, to record the occupancy grid map when circumnavigating the reconnaissance target, and to transmit the recorded occupancy grid map to the teleoperation console in the teleoperation mode.

7. The mobile robot reconnaissance system according to claim 5, wherein the software instructions stored in the memory store further include a street-following routine corresponding to a street-following robot mission,

wherein the street-following routine, when executed by the processor, is configured to cause the mobile robot to navigate to a first location selected by the operator in the teleoperation mode, to identify a street using a scaled vector field histogram in the autonomous mode, to traverse the identified street to a specified distance from the initial location in the autonomous mode, to record the occupancy grid map when traversing the identified street in the autonomous mode, to return to the first location in the autonomous mode, and to transmit the recorded occupancy grid map to the teleoperation console in the teleoperation mode.

8. The mobile robot reconnaissance system according to claim 5, wherein the mobile robot further includes an operator interface disposed on the mobile robot and configured to be operated by the operator,

wherein the mobile robot is further configured to perform at least one of the robot missions in the autonomous mode starting from an initial location of the mobile robot when the operator interface is operated.

9. A mobile robot reconnaissance system, comprising:

a mobile robot configured to perform autonomous reconnaissance, including;

a drive system configured to propel the mobile robot across terrain,

a range sensor configured to detect a distance between the mobile robot and one or more objects in an environment of the mobile robot,

a processor communicatively connected to the range sensor and to the drive system, and configured to execute software instructions,

a memory store communicatively connected to the processor, the memory store having stored thereon a plurality of software instructions configured to be executed by the processor, the software instructions including;

a mapping routine configured to maintain an occupancy grid map of the environment of the mobile robot,

a linear feature routine configured to detect one or more linear patterns in the occupancy grid map and to determine a strongest line among the one or more linear patterns, and

a navigational routine configured to control the drive system to move the mobile robot in a direction aligned with the strongest line among the one or more linear patterns, and

a transceiver configured to transmit the occupancy grid map and to receive a mission command; and

a teleoperation console configured to remotely communicate with the mobile robot, the teleoperation console including;

a display configured to present the occupancy grid map transmitted by the mobile robot to an operator and to present a mission command menu to the operator, the mission command menu including a plurality of visual items each corresponding to at least one of a plurality of robot missions performable by the mobile robot,

an input unit configured to receive a mission command selection from the operator corresponding to at least one of the robot missions, and

a transmitter configured to transmit the mission command to the mobile robot corresponding to the mission command selection received by the input unit,

wherein the robot missions each include a teleoperation mode and an autonomous mode,

wherein the mobile robot is further configured to communicate with the teleoperation console in the teleoperation mode and to function autonomously in the autonomous mode even without communication with the teleoperation console.

10. The mobile robot reconnaissance system according to claim 9, wherein the software instructions stored by the memory store further include a circumnavigation routine corresponding to a circumnavigation robot mission,

wherein the circumnavigation routine, when executed by the processor, is configured to cause the mobile robot to navigate to a location selected by the operator in the teleoperation mode, to circumnavigate a reconnaissance target identified using a scaled vector field histogram in the autonomous mode, to record the occupancy grid map when circumnavigating the reconnaissance target, and to transmit the recorded occupancy grid map to the teleoperation console in the teleoperation mode.

11. The mobile robot reconnaissance system according to claim 9, wherein the software instructions stored in the memory store further include a street-following routine corresponding to a street-following robot mission,

wherein the street-following routine, when executed by the processor, is configured to cause the mobile robot to navigate to a first location selected by the operator in the teleoperation mode, to identify a street using a scaled vector field histogram in the autonomous mode, to traverse the identified street to a specified distance from the initial location in the autonomous mode, to record the occupancy grid map when traversing the identified street in the autonomous mode, to return to the first location in the autonomous mode, and to transmit the recorded occupancy grid map to the teleoperation console in the teleoperation mode.

12. The mobile robot reconnaissance system according to claim 9, wherein the mobile robot further includes an operator interface disposed on the mobile robot and configured to be operated by the operator,

wherein the mobile robot is further configured to perform at least one of the robot missions in the autonomous mode starting from an initial location of the mobile robot when the operator interface is operated.

13. The mobile robot reconnaissance system according to claim 9, wherein the software instructions stored by the memory store further include a rallying routine,

wherein the mobile robot is configured to execute the rallying routine when communication with the teleoperation console fails when the mobile robot is operating in the teleoperation mode, and

wherein the rallying routine, when executed by the processor, is configured to cause the mobile robot to move toward a predetermined location and/or to reverse a heading of the mobile robot until communication is established with the teleoperation console.