Process for navigating an unmanned vehicle and a vehicle for the same

• US 5,377,106 A
• Filed: 06/23/1992
• Issued: 12/27/1994
• Est. Priority Date: 03/24/1987
• Status: Expired due to Fees

• Current Assignee: Fraunhofer Gesellschaft Zur Foerderung Der Angewandten Forsching E.V.
• Original Assignee: Fraunhofer Gesellschaft Zur Foerderung Der Angewandten Forsching E.V.
• Inventors: Forster, Stefan, Drunk, Gerhard, Hug, Christoph, Langen, Achim, Mullerschon, Joachim
• Primary Examiner(s): Chin, Gary
• Application Number:
  US07/913,790
• Time in Patent Office: 917 Days
• Field of Search: 364/424.02, 364/424.01, 318/587, 180/167, 180/168, 180/169
• US Class Current: 701/25
• CPC Class Codes: G05D 1/0255 using acoustic signals, e.g. ultra-sonic singals sonar systems designed for anti-collision purposes G01S15/93

Abstract

Disclosed is a process for navigating an unmanned vehicle over a predeterable course, respectively such a vehicle. A steering and control unit determines by a first sensor at least the stretch covered and detects by at least one second sensor objects in the vicinage the position of which is stored in the steering and control unit and which serve the purpose of checking the position of the vehicle computed on the basis of the covered stretch. In accordance with the present invention the distance of the vehicle from the objects in the vicinage stored with their exact position in relation to the planned path in the steering and control unit is ascertained by the second sensor at points on the path spaced at intervals. The ascertained distance is compared with the stored distance of the planned coordinates of the point on the path from the object in vicinage.

Claims

1. An unmanned vehicle, comprising:

a control unit which controls a steer angle and revolutions of at least one wheel of the vehicle, and in which a freely determinable path to be travelled by the vehicle as well as positions of objects in a vicinity of the area of the path are stored in memory;

a first sensor unit coupled to the control unit, said first sensor unit sensing a path covered by the vehicle and the direction of the covered path, the output signal of the first sensor unit being fed to the control unit;

a second sensor unit coupled to the control unit, the second sensor being used as a data correction gathering mechanism, the output signals of the second sensor unit being fed to the control unit, the second sensor unit having at least three sensors which measure distances between the vehicle and objects in the area of the path, one of said sensors measuring a corresponding first distance in the direction of the longitudinal axis of the vehicle, and the other two of said sensors measuring second and third distances to objects in the vicinity of the area of the path in the direction of the transverse axis of the vehicle, whereby the second and third distances which are offset in the direction of the longitudinal axis of the vehicle are measured to one object in the vicinity of the path;

wherein the control unit compares at least the second and third distances measured by the second sensor unit with expected distances to the stored position of the objects in the vicinity of an expected position and a desired alignment of the vehicle based on the output signals of the first sensor unit and corrects the actual position and the actual alignment of the vehicle at at least one of predeterminable time intervals and at certain points of the path based on the comparison.

2. A vehicle according to claim 1, wherein the second sensors are arranged to measure distances to smooth surfaces existing in the area of the course, to edges and ceiling projections.

3. A vehicle according to claim 2, wherein the control unit carries out correcting driving movements when the actual position or actual alignment deviates from the desired position or desired alignment.

4. A vehicle according to claim 1, wherein the control unit changes a desired-course coordinate corresponding to a determined actual position of the vehicle when the determined actual position is situated on a given course but deviates from a desired position, and the alignment of the vehicle is proper in relation to a desired path.

5. A vehicle according to claim 4, wherein the control unit compares an expected distance with the distance measured to the objects in the vicinity of the path when, on the basis of the position determined from the output signals of the first sensor, an object in the vicinity of the path whose position is stored is reached or when the vehicle is to perform a change of direction.

6. A vehicle according to claim 5, wherein the sensors of the second sensor unit are distance-measuring ultrasonic sensors.

7. A vehicle according to claim 6, wherein at least two of said sensors of the second sensor units are offset in the direction of the longitudinal axis of the vehicle and are arranged on each vehicle side.

8. A vehicle according to claim 7, wherein two of said sensors of the second sensor units are mounted on a same vehicle side and measure distances of the vehicle from the same object in the vicinity of the path in the direction of the transverse axis of the vehicle.

9. A vehicle according to claim 8, wherein the second sensor unit further includes at least one sensor directed to a ceiling of a room.

10. A vehicle according to claim 9, wherein the control unit, for the measuring of the distances offset in the direction of the longitudinal axis of the vehicle to objects in the vicinity of the path in the direction of the transverse axis of the vehicle, repeats the measurement of the distance to one object in the vicinity of the area of the path, the position of said object being stored, after a defined travelling course of the vehicle.

11. A vehicle according to claim 10, wherein the first sensor unit has a pulse generator coupled with at least one wheel.

12. A vehicle according to claim 11, wherein the first sensor unit has a sensor which senses the steer angle of at least one wheel.

13. A vehicle according to claim 12, further comprising a further sensor that provides an output signal from which the control unit determines the position of the vehicle relative to a stop.

14. A vehicle according to claim 13, wherein said further sensor is an optical distance sensor which, for the determination of the position of the vehicle relative to a stop, senses the position of a rectangular edge of a flat surface at short time intervals.

15. A vehicle according to claim 14, wherein the vehicle during position sensing when approaching a station travels in a straight line and a distance measurement takes place approximately each millimeter of travelling path.

16. A vehicle according to claim 15, further comprising a plurality of obstacle sensors coupled to the control unit.

17. A vehicle according to claim 16, further comprising crash monitoring sensors provided in the front area of the vehicle on a circular arc and which are directed vertically downward, the crash monitoring sensors being coupled to the control unit.

18. A vehicle according to claim 17, wherein the crash monitoring sensors are infrared sensors.

19. A vehicle according to claim 17, further comprising, at least on a front side and in a front side area of the vehicle, ultrasonic obstacle sensors, coupled to the control unit, having sound lobes which are shaped by sound channels connected in front of the obstacle sensors such that at least one sound field is formed which completely covers an area to be monitored.

20. A vehicle according to claim 19, wherein three of said ultrasonic obstacle sensors produce a sound field completely covering the area to be monitored, said sound field being symmetrical to a horizontal plane propagating in the same manner above and below the plane.

21. A vehicle according to claim 20, wherein at least one group of three of said ultrasonic obstacle sensors produce a sound field aimed diagonally forward and downward completely covering an area to be monitored.

22. A vehicle according to claim 19, further comprising two optical obstacle sensors, coupled to the control unit, provided in the area of a lateral front edge of the vehicle, one of said optical obstacle sensors beaming at an angle of from 15°

to 40°

with respect to the longitudinal axis of the vehicle, and the other of said optical obstacle sensors beaming at an angle of from 50°

to 70°

with respect to the longitudinal axis of the vehicle toward the front.

23. A vehicle according to claim 16, wherein the control unit stops the vehicle when one of the obstacle sensors senses an obstacle in the travelling path of the vehicle.

24. A vehicle according to claim 16, wherein the control unit initiates an evading movement of the vehicle when the control unit senses an obstacle in the travelling path of the vehicle.

25. A vehicle according to claim 16, wherein the second sensors of the second sensor units and the obstacle sensors have essentially identical ultrasound emitters, the beaming characteristic of which is affected by sound channels.

26. A vehicle according to claim 25, wherein said sound channels, which focus an ultra-sound bundle to ±

5°

, are mounted on the vehicle in front of the ultra-sound emitters of the second sensors of the second sensor units.

27. A vehicle according to claim 25, wherein said sound channels, which focus an ultra-sound bundle to ±

5°

, in a plane perpendicular to the floor and to ±

30°

in a plane parallel to the floor, are mounted on the vehicle in front of the ultra-sound emitters of the obstacle sensors.

28. A vehicle according to claim 16, wherein the obstacle sensors send signals to the control unit for providing additional information regarding navigation in the area close to the wall.

29. A vehicle according to claim 1, wherein program data of a new travelling course is stored in said memory of the control unit off-line interactively with a personal computer, with the program data being transferrable at a station or by teletransmission to the control unit of the vehicle.

30. A vehicle according to claim 1, wherein the vehicle is a cleaning vehicle.

31. A vehicle according to claim 30, further comprising a cleaning brush on the bottom of said vehicle having a vacuum device arranged above it.

32. A vehicle according to claim 29, wherein the vehicle is an industrial truck.