Autonomous working machine such as autonomous lawn mower

• US 10,321,625 B2
• Filed: 12/30/2016
• Issued: 06/18/2019
• Est. Priority Date: 12/30/2015
• Status: Active Grant

• Current Assignee: Honda Research Institute Europe GmbH (Honda Motor Company)
• Original Assignee: Honda Research Institute Europe GmbH (Honda Motor Company)
• Inventors: Einecke, Nils, Franzius, Mathias, Deigmoller, Jorg
• Primary Examiner(s): Oh, Harry Y
• Application Number:
  US15/394,889
• Publication Number:
  US 20170188510A1
• Time in Patent Office: 900 Days
• Field of Search: 700259
• CPC Class Codes: A01D 2101/00 Lawn-mowers
• CPC Class Codes: A01D 34/008 for automated or remotely controlled operation
• CPC Class Codes: B60R 11/04 Mounting of cameras operative during drive; Arrangement of controls thereof relative to the vehicle
• 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 1/0253 extracting relative motion information from a plurality of images taken successively, e.g. visual odometry, optical flow determining position or orientation from images G06T7/70
• 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 1/0272 comprising means for registering the travel distance, e.g. revolutions of wheels measuring distance traversed on the ground by vehicles, e.g. using odometers G01C22/00
• CPC Class Codes: G06T 2207/10012 Stereo images
• CPC Class Codes: G06T 2207/30252 Vehicle exterior; Vicinity of vehicle
• CPC Class Codes: G06T 7/70 Determining position or orientation of objects or cameras camera calibration G06T7/80
• CPC Class Codes: G06V 20/56 exterior to a vehicle by using sensors mounted on the vehicle
• CPC Class Codes: H04N 13/204 using stereoscopic image cameras stereoscopic photography G03B35/00
• CPC Class Codes: H04N 7/183 for receiving images from a single remote source

Abstract

The invention regards an autonomous working machine comprising drive means, current position estimation means, control means including a driving control unit and a camera. With aid of the current position estimation means the current position of the autonomous working machine is estimated. Furthermore, the driving control unit generates driving commands for the driving means on the basis of an intended movement of the autonomous working machine and the estimated current position. The camera is configured to capture images of the environment of the working machine. For estimating the current position, the current position estimation means is formed by the control means, which is configured to apply visual odometry on the captured images for estimating the current position of the working machine.

Claims

1. An autonomous working machine comprising:

driving means;

memory for storing information indicating an intended path which the autonomous working machine shall follow;

control means including a current position estimation unit for estimation of a current position of the autonomous working machine, and a driving control unit for generating initial driving commands for the driving means, wherein the driving commands are generated on the basis of an estimated current position such that the resulting operation of the driving means leads to the autonomous working machine following precisely the intended path; and

a camera configured to capture images of an environment of the autonomous working machine,

wherein the control means is configured to apply visual odometry on the captured images for estimating the current position of the autonomous working machine,

to compare the estimated current position to a corresponding position that should be reached in case that the autonomous working machine would perfectly follow the intended driving path,

to generate a correction signal on the basis of a difference thereof, and

to add the correction signal to the initial driving commands, and wherein

the control means is configured to accumulate the results of the visual odometry calculation since the detection of a vicinity of a charging station for the autonomous working machine or leaving the same to start a working operation, and to use the accumulated results in order to guide back the autonomous working machine to the charging station.

2. An autonomous working machine according to claim 1, wherein

the camera is a stereo camera.

3. An autonomous working machine according to claim 2, wherein

the control means is configured to compute 3D data from stereo images captured by the stereo camera and use the 3D data to improve current position estimation.

4. An autonomous working machine according to claim 1, wherein

the control means is configured to use ground plane assumption to improve current position estimation.

5. An autonomous working machine according to claim 1, wherein

the camera is mounted on the working machine so as to face a forward driving direction.

6. An autonomous working machine according to claim 1, wherein

the control means is configured to adapt a time gap between images used for visual odometry according to the intended movement.

7. An autonomous working machine according to claim 6, wherein

time gaps are shorter for turning movements than for straight drive or slow movement.

8. An autonomous working machine according to claim 6, wherein

visual odometry is performed using different time gaps and results are merged afterwards.

9. An autonomous working machine according to claim 1, wherein

results of visual odometry is merged with results for position estimation based on wheel odometry or IMU.

10. An autonomous working machine according to claim 1, wherein

the control means is configured to detect wheel slip on the basis of said difference.

11. An autonomous working machine according to claim 1, wherein

the autonomous vehicle further comprises recognition means to recognize predetermined events and the control means is configured to store information on occurrence of such events related to an estimated current position at the time of occurrence.

12. An autonomous working machine according to claim 1, wherein

the autonomous working machine is an autonomous lawn mower or an autonomous scarifier.