Orientation device for electrically operated transportation vehicles, automatically guided in factory building

Abstract

The invention relates to a device and method for the orientation of electrically driven transport vehicles, especially so-called AGVs (automatic guided vehicles), automatically guided in factory buildings, the invention having the following features: a) a camera for identifying the reference points of a planned route using markers, in particular on the basis of the data matrix code, wherein a position marker is made up of an arrangement of nine data matrix codes arranged in a square, and wherein the diagonals of 3 individual codes are located on a straight line; b) a front ultrasound sensor and a rear ultrasound sensor; c) a laser scanner; and d) a light-field sensor.

Claims

1. An orientation device for electrically operated transportation vehicles, automatically guided in factory buildings, comprising: a) a data matrix camera for identifying the reference points of a planned route by means of position markers, wherein each position marker is constructed from an arrangement composed of nine data matrix codes which are arranged in a square, and wherein diagonals of three individual data matrix codes are located on a straight line, b) a front ultrasound sensor and a rear ultrasound sensor, c) a laser scanner, and d) a light field sensor.

2. The orientation device as claimed in claim 1, wherein the data matrix camera for illuminating the detection field is surrounded by a multiplicity of LEDs.

3. The orientation device as claimed in claim 2, wherein the multiplicity of LEDs are arranged in a circular shape, wherein the camera is screened from scattered light by means of a cylinder, and wherein each LED is additionally surrounded by an annular reflector.

4. The orientation device as claimed in claim 1 further comprising a charging mat with a marker which serves to detect a position.

5. An orientation method for electrically operated transportation vehicles, automatically guided in factory buildings, comprising: a) ordering a specific transportation vehicle (AGV) having a heavy-load rack to transport the heavy-load rack to a specific destination according to a predefined planned route, b) instructing the specific transportation vehicle to follow a predefined planned route from reference point to reference point, wherein the reference points have corresponding markers of the predefined planned route that are detected by a camera on the specific transportation vehicle (AGV), and wherein the orientation over a large area is carried out in conjunction with a light field sensor by means of a laser scanner, c) off-loading the heavy-load rack on the transportation vehicle (AGV) at the specific destination.

6. The orientation method as claimed in claim 5, wherein the specific transportation vehicle (AGV) comprises front and back ultrasound sensors, and relatively small potential obstacles are detected by the front ultrasound sensor during forward travel, and by the rear ultrasound sensor during rearward travel.

7. The orientation method as claimed in claim 5, wherein the markers are configured according to a data matrix code, wherein a position marker is constructed from an arrangement composed of nine data matrix codes which are arranged in a square, and wherein the diagonals of three individual codes are located on a straight line.

8. The orientation method as claimed in claim 5, wherein the transportation vehicle (AGV) is deficient in energy, a charging mat is driven to in order to recharge the electrical accumulators.

9. A computer program having a program code for carrying out the method steps as claimed in claim 5, wherein the program is run in a computer.

10. A machine-readable carrier having the program code of a computer program for carrying out the method as claimed in claim 5, wherein the program is run in a computer.

Description

(1) The device according to the invention is described in more detail below.

(2) In particular:

(3) FIG. 1: shows a factory building with transportation carriages,

(4) FIG. 2: shows an illustration of the data matrix code which is used,

(5) FIG. 3: shows possibilities of correcting a selected route,

(6) FIG. 4: shows a side view of an AGV with a lifting plate,

(7) FIG. 5 shows a view of a detail of the data matrix camera,

(8) FIG. 6 shows an illustration of a data matrix code on a charging mat.

(9) FIG. 1 shows a factory building with transportation carriages. Here, a detail from a comparatively large factory building with transportation carriage 1 is illustrated. Order picking stations 3 serve to collect the goods which are required for a delivery. If waiting times arise at the order picking stations during the work, the corresponding transportation carriages 1 wait in the region of waiting loops 2 which are equipped with induction lines which are laid in the floor, in order to use such waiting times to charge electrical accumulators with the respective used AGV systems.

(10) FIG. 2 shows an illustration of the data matrix code which is used. 4 denotes here the data matrix code carrier, and 5 denotes the selected code itself. In addition to the marking of goods or locations, a data matrix code is known as a marker. A data matrix code is attached here to the floor or to some other underlying surface and is detected, when a vehicle travels over it, by a camera which is mounted on the vehicle and directed downward. In the respective marker information is encoded which relates, for example, to the position of the location and/or contains other specific information.

(11) A data matrix code is composed of light or dark cells which are arranged as a data matrix. The individual cells are configured in a square and should not exceed a tolerance of plus or minus 10%.

(12) Basically, in the case of a data matrix code the position of the individual cells (location) and the filling of a cell are evaluated, wherein a black cell corresponds to binary one, and a white cell to binary zero.

(13) The data matrix code is delimited by two search elements which serve to detect a location during the reading of the code. Search elements are a horizontal boundary line and a vertical boundary line which are located with respect to one another in the shape of a L. The search elements serve also to detect distortions and to determine the size. The two interrupted lines (alternating grid or clock cycle lines) opposite the search elements serve as a basis for the creation of the data matrix. The search elements and the clock cycle cells surround the region of the useful data. This region also contains the redundant data for the data protection which is calculated according to the Reed Solomon error correction algorithm.

(14) By using the known data matrix technology, according to FIG. 2, a novel arrangement of a marker is provided in which a position marker is constructed from an arrangement composed of nine data matrix codes. These data matrix codes are arranged in a square, wherein in each case the diagonals of the three individual codes are located on a straight line.

(15) In this context, the same information on the position of the location and on the characterization of the location is encoded firstly for all the individual codes.

(16) In addition, a further symbol is encoded with the result that each individual code has uniquely assignable detection.

(17) By means of the sensor devices which are located on a vehicle which can travel over the marker which is shown, one or more individual codes are detected during the travel. As a result of known image detection methods (such as, for example, data matching), both the stored information and the relative orientation of the camera and code are detected here.

(18) If the novel arrangement of a marker which is shown is located at an intersection point of various travel routes, this code can be equally well read from all directions. In the event of a rotation of a vehicle travelling over the code at the center point of the code, the sensor data (rotational angle) can be used to position the vehicle.

(19) Deviations from a planned route can be detected by virtue of the fact that the information content of the respectively detected codes is evaluated.

(20) In this way, a lateral deviation from the center line and/or a deviation in the travel angle from a selected route can be detected. This information permits immediate correction of the selected route.

(21) FIG. 3 shows possibilities of corrections of a selected route. The data matrix code carrier 4 with the specific data matrix code 5 is shown here again. The ideal line 7 of a travel line such as would be shown to the camera 6 of an AGV, is illustrated in the center. To the left and right of the ideal line 7, in each case a travel line is shown which has a specific offset angle with respect to the ideal line 7.

(22) FIG. 4 shows a side view of an AGV with a lifting plate.

(23) The AGV housing 15 has a lifting plate 12 with a transportation rack 10 resting on it with order-picked goods 11. In the center of the AGV it is possible to see one of the two drive wheels 17, accompanied by two supporting rollers 18. In this region, an induction line 14 is illustrated in the floor, and an induction current collector 16 is illustrated on the vehicle.

(24) The identification of the information of a data matrix code is performed by a data matrix camera 19. A front ultrasound sensor 20 and a rear ultrasound sensor 13 detect obstructive structures in the region close to the floor, even during reversing.

(25) In a particular embodiment, small stones which are lying on the floor but nevertheless disrupt the driving operation, or other obstacles, can be moved out of the way in these regions by means of air nozzles using pulse-like blasts of air. Such small obstacles can lead to difficulties, in particular in the case of AGVs with heavy loads.

(26) A laser scanner 9 on the front side of the AGV detects orientation structures over a large area and with relevant detail.

(27) In addition, a light field sensor 21 is mounted on the front side of the transportation vehicle. The information which is acquired by means of this optical sensor can advantageously be used to calculate, after the actual recording, an image with a focus level which is located at any desired position, and to display or evaluate said image. The same optical sensor can therefore be used both for focused display of objects located very close as well as for focused display of objects located very far away, wherein, furthermore, both displays can be calculated from the same acquired information. The provision of a costly lens system, zoom system or auto-focusing system as an optical sensor is avoided here. Furthermore, the same acquired data can be used for the simultaneous calculation of different image displays, in each case with different portions of the image and different focus levels and regions with different focus depths.

(28) With respect to the light field sensor 21 which is used, reference is made to the new development of the so-called mini-lenses which collect optical information in the form of hundreds of mini-lenses according to the light field principle, which information can then be combined later by means of data technology to form images with a desired resolution and/or a desired viewing angle. Such mini-lenses are 3-D enabled, are inexpensive to manufacture and follow the principle of an insect's eye.

(29) In combination with the laser scanner 9, it is easily possible for the transportation vehicle to navigate between the collection of transportation racks and to cope adequately with obstacles which appear unexpectedly.

(30) The orientation system which is presented here can be used for all types of AGVs. In particular, reference is also made here to an AGV for the transportation of heavy loads by means of a lifting arrangement composed of three lifting pins.

(31) The electronic devices which are necessary for operating the orientation system are known to a person skilled in the art and are not described in more detail.

(32) FIG. 5 shows a view of a detail of the data matrix camera. Here, in the image part a) it can be seen that the actual camera 25 is surrounded by a multiplicity of LEDs 23 arranged in a circular shape in order to illuminate the detection field, wherein the camera 25 is screened against scattered light by means of a cylinder 24. In the image part b) it is apparent that each LED is additionally surrounded by an annular reflector 22.

(33) FIG. 6 shows an illustration of a data matrix code on a charging mat.

(34) A charging mat is an especially formed, planar structure which has, in its interior, a continuous conductor track which covers the entire surface and which permits a vehicle to take up electrical energy inductively by means of suitable current collector. A control and energy supply line 27 for a charging mat 26 is used for this purpose. In order to detect the charging mat 26, a data matrix carrier 4 is arranged in the central region of the charging mat 26, said data matrix carrier 4 having a data matrix code 5 relating to this.

(35) In order to control the described transportation vehicles, a known method is preferably used which has been developed by the Technical University of Berlin and was published on Oct. 10, 2007, with the title: Dynamic Routing of Automated Guided Vehicles in Real-Time (Ewgenij Gawrilow, Ekkehard K?hler, Rolf H. M?hring, Bj?rn Stenzel) (http://www.math.tuberlin.de/coga/publications/techreports/]

(36) This essentially involves a two-part algorithm whose first part comprises a preparatory step and whose second part calculates a route in real time and provides a specific time window for each section here. The application of the method described here relates to an AGV network in the container terminal of Altenwerder in the port of Hamburg. The application of the same method for fault-free operation of automated guided vehicles in a warehouse appears, in contrast, to be novel.

(37) The control of the complex movement processes and the signal processing of the sensors used require a specific control program.

LIST OF REFERENCE NUMERALS

(38) 1 Transportation carriages 2 Induction lines in a waiting loop 3 Order picking stations 4 Data matrix code carrier 5 Data matrix code 6 Camera of an AGV 7 Ideal line of a travel line 8 Offset angle of a travel line 9 Laser scanner 10 Transportation rack 11 Order picked goods 12 Lifting plate 13 Rear ultrasound sensor 14 Induction line 15 AGV housing 16 Induction current collector 17 Drive wheel 18 Supporting roller 19 Data matrix camera 20 Front ultrasound sensor 21 Light field sensor 22 Reflector 23 LED 24 Cylinder 25 Camera 26 Charging mat 27 Control and energy supply line