Method and system for positioning an autonomous mobile unit for docking

• US 6,504,610 B1
• Filed: 07/22/1999
• Issued: 01/07/2003
• Est. Priority Date: 01/22/1997
• Status: Expired due to Fees

• Current Assignee: Siemens AG
• Original Assignee: Siemens AG
• Inventors: Bauer, Rudolf, Magnussen, Björn
• Primary Examiner(s): Stafira, Michael P.
• Application Number:
  US09/355,055
• Time in Patent Office: 1,265 Days
• Field of Search: 356/399-401
• US Class Current: 356/399
• CPC Class Codes: G01B 11/272 using photoelectric detection means
• CPC Class Codes: G01S 1/70 using electromagnetic waves other than radio waves
• CPC Class Codes: G01S 3/784 using a mosaic of detectors
• CPC Class Codes: G01S 5/16 using electromagnetic waves other than radio waves
• CPC Class Codes: G05D 1/0225 involving docking at a fixed facility, e.g. base station or loading bay parking aids B62D15/027
• CPC Class Codes: G05D 1/0234 using optical markers or beacons optical beacons per se G01S1/70
• CPC Class Codes: G05D 1/0236 in combination with a laser lasers per se H01S
• CPC Class Codes: G05D 1/0242 using non-visible light signals, e.g. IR or UV signals

Abstract

A system and a method for positioning an autonomous mobile unit for docking, wherein a slot-shaped light beam which stands perpendicular to the drive surface of the unit is provided, which beam is emitted by a docking device, and position-sensitive detectors for this light beam are present on the unit, these being arranged parallel to the drive surface of the unit. With the aid of the light beam and of the detectors, the precise rotation (beta) of the unit relative to the docking device can be determined, whereby the unit learns its approximate configuration in space by means of ultrasound or odometry measurements. With this guidance, the unit can dock very precisely at a docking device in order to be able to take on goods or to drive into a garage, for example. Position-sensitive detectors, or photodiodes are provided as receptors for the light beam. The present invention preferably can be used in household robots or in industrial cleaning robots.

Claims

1. A system for positioning an autonomous mobile unit for docking, comprising:

a transmitter and a detector arrangement, wherein one of the transmitter and the detector arrangement is arranged at the autonomous mobile unit and the other of the transmitter and the detector arrangement is arranged at a docking device, the transmitter emitting a slot-shaped light beam which is substantially perpendicular to a drive surface of the autonomous mobile unit, the detector arrangement including at least one position detector which is oriented substantially parallel to the drive surface, the detector arrangement for detecting a position of the light beam;

an evaluator which receives data from the detector arrangement and evaluates a change of relative position of the light beam with respect to the detector arrangement to control movement of the autonomous mobile unit wherein the light beam assumes a predetermined position on the detector arrangement; and

three-wheel kinematics, wherein it is determined whether it is possible for the autonomous mobile unit to attain a desired docking position based on the kinematics and depending on a docking interval, and the autonomous mobile unit is distanced from the docking device, if it is determined that it is not possible for the autonomous mobile unit to attain the desired docking position, sufficiently far enough to enable the autonomous mobile unit to ultimately attain the desired docking position.

2. A system for positioning an autonomous mobile unit for docking as claimed in claim 1 further comprising an actuator for activating the transmitter given a failure to exceed the docking interval.

3. A system for positioning an autonomous mobile unit for docking as claimed in claim 1, wherein the detector arrangement includes at least two position detectors arranged one behind the other in a main direction of approach to the docking device of the autonomous mobile unit.

4. A system for positioning an autonomous mobile unit for docking as claimed in claim 1, wherein the position detector is a conventional position-sensitive detector.

5. A system for positioning an autonomous mobile unit for docking as claimed in claim 1, wherein the position detector includes photodiodes.

6. A system for positioning an autonomous mobile unit for docking as claimed in claim 1, wherein the position detector includes photo transistors.

7. A system for positioning an autonomous mobile unit for docking as claimed in claim 1, wherein the transmitter includes a laser for generating the light beam.

8. A system for positioning an autonomous mobile unit for docking as claimed in claim 1, wherein the transmitter includes both a filament lamp and a Fresnel lens for generating the light beam.

9. A system for positioning an autonomous mobile unit for docking as claimed in claim 2, wherein the actuator includes an infrared sensor.

10. A method for docking an autonomous mobile unit at a docking device, the method comprising the steps of:

arranging one of a transmitter and a detector arrangement at the autonomous mobile unit and the other of the transmitter and the detector arrangement at the docking device;

emitting a slot-shaped light beam from the transmitter, the light beam being substantially perpendicular to a drive surface of the autonomous mobile unit;

detecting a position of the light beam with the detector arrangement, the detector arrangement including at least one position detector oriented substantially parallel to the drive surface;

receiving data from the detector arrangement at an evaluator;

evaluating a change of relative position of the light beam with respect to the detector arrangement via the evaluator;

controlling movement of the autonomous mobile unit wherein the light beam assumes a predetermined position on the position detector;

providing three-wheel kinematics for the autonomous mobile unit;

determining whether it is possible for the autonomous mobile unit to attain a desired docking position based on the kinematics and depending on a docking interval; and

distancing the autonomous mobile unit from the docking device, if it is determined that it is not possible for the autonomous mobile unit to attain the desired docking position, sufficiently far enough to enable the autonomous mobile unit to ultimately attain the desired docking position.

11. A method for docking an autonomous mobile unit at a docking device, the method comprising the steps of:

arranging one of a transmitter and a detector arrangement at the autonomous mobile unit and the other of the transmitter and the detector arrangement at the docking device;

emitting a slot-shaped light beam from the transmitter, the light beam being substantially perpendicular to a drive surface of the autonomous mobile unit;

detecting a position of the light beam with the detector arrangement, the detector arrangement including at least one position detector oriented substantially parallel to the drive surface;

receiving data from the detector arrangement at an evaluator;

evaluating a change of relative position of the light beam with respect to the detector arrangement via the evaluator;

controlling movement of the autonomous mobile unit wherein the light beam assumes a predetermined position on the position detector;

determining, in cyclical fashion, integral brightness differences in an environment of the autonomous mobile unit; and

evaluating the brightness differences as interval changes to obstacles in the environment.

12. A method for docking an autonomous mobile unit at a docking device, the method comprising the steps of:

providing at least two distance measuring sensors at a side of the autonomous mobile unit;

determining a distance to a wall placed to a side of the docking device using the at least two distance measuring sensors;

determining a distance to the docking device using at least one further distance measuring sensor provided at the autonomous mobile unit;

determining a configuration of the autonomous mobile unit from the distance to the docking device and from the measured distance to the wall; and

forming control signals for a docking procedure based on the configuration of the autonomous mobile unit.

13. A system for positioning an autonomous mobile unit for docking, comprising:

a transmitter and a detector arrangement, wherein one of the transmitter and the detector arrangement is arranged at the autonomous mobile unit and the other of the transmitter and the detector arrangement is arranged at a docking device, the transmitter emitting a slot-shaped light beam which is substantially perpendicular to a drive surface of the autonomous mobile unit, the detector arrangement including at least one position detector which is oriented substantially parallel to the drive surface, the detector arrangement for detecting a position of the light beam; and

an evaluator which receives data from the detector arrangement and evaluates a change of relative position of the light beam with respect to the detector arrangement to control movement of the autonomous mobile unit wherein the light beam assumes a predetermined position on the detector arrangement, wherein integral brightness differences in an environment of the autonomous mobile unit are determined in cyclical fashion, and the brightness differences as interval changes to obstacles in the environment are evaluated.

14. A system for positioning an autonomous mobile unit for docking as claimed in claim 13, further comprising:

means for determining a docking interval between the autonomous mobile unit and the docking device; and

an actuator for activating the transmitter given a failure to exceed the docking interval.

15. A system for positioning an autonomous mobile unit for docking as claimed in claim 13, wherein the detector arrangement includes at least two position detectors arranged one behind the other in a main direction of approach to the docking device of the autonomous mobile unit.

16. A system for positioning an autonomous mobile unit for docking as claimed in claim 13, wherein the position detector is a conventional position-sensitive detector.

17. A system for positioning an autonomous mobile unit for docking as claimed in claim 13, wherein the position detector includes photodiodes.

18. A system for positioning an autonomous mobile unit for docking as claimed in claim 13, wherein the position detector includes photo transistors.

19. A system for positioning an autonomous mobile unit for docking as claimed in claim 13, wherein the transmitter includes a laser for generating the light beam.

20. A system for positioning an autonomous mobile unit for docking as claimed in claim 13, wherein the transmitter includes both a filament lamp and a Fresnel lens for generating the light beam.

21. A system for positioning an autonomous mobile unit for docking as claimed in claim 14, wherein the actuator includes an infrared sensor.