Abstract
A conveying apparatus for conveying laden or unladen load carriers, having a first conveying unit and a second conveying unit, wherein each conveying unit can be displaced on ground-level rollers and the first and the second conveying units can be moved relative to one another and independently of one another. A device is provided for determining the position and the location of the first conveying unit relative to the second conveying unit, the device having a camera, which is arranged on the first conveying unit, and having a feature arranged on the second conveying unit, or a combination of features arranged on the second conveying unit, wherein the feature or the combination of features has an extent in the direction of travel and an extent perpendicular to the direction of travel, wherein the extents can be sensed by the camera. A conveying unit for a conveying apparatus is also provided.
Claims
1. A conveying unit for a conveying apparatus for conveying laden or unladen load carriers comprising: a) a carrying side; b) ground-level rollers disposed opposite the carrying side so that the conveying unit is displaceable along a direction of travel, c) a camera for capturing an image of a feature provided on a surface or of a feature combination, wherein the feature or the feature combination has an extent in the direction of travel and an extent perpendicular to the direction of travel, and the extents are capturable by the camera, wherein the conveying unit has a projection device for projecting the feature or the feature combination from the conveying unit onto the surface.
2. The conveying unit as claimed in claim 1, wherein the conveying unit is set up to ascertain at least a distance of the conveying unit and an angle between the conveying unit and the extent of the feature in the direction of travel on the basis of the captured image.
3. A conveying apparatus for conveying laden or unladen load carriers comprising: a) a first conveying unit and a second conveying unit, wherein each conveying unit is displaceable on ground-level rollers, and the first conveying unit and the second conveying unit are movable relative to one another and independently of one another along a respective direction of travel, b) a device for determining the position and the location of the first conveying unit relative to the second conveying unit, having i) a camera arranged at the first conveying unit, ii) a feature arranged at the second conveying unit or a feature combination arranged at the second conveying unit, wherein the feature or the feature combination has an extent in the direction of travel and an extent perpendicular to the direction of travel, wherein the extents are capturable by the camera.
4. The conveying apparatus as claimed in claim 3, wherein the camera and the feature or the feature combination are arranged at the first conveying unit and the second conveying unit in a manner such that a camera axis is aligned with the feature or the feature combination, and the camera axis encloses an angle that is not equal to 90 with the extent in the direction of travel of the feature or of the feature combination.
5. The conveying apparatus as claimed in claim 4, wherein the angle is between 70 and 20.
6. The conveying apparatus as claimed in claim 4, wherein the angle is 4515.
7. The conveying apparatus as claimed in claim 3, wherein the feature or the feature combination is structural and/or placed by adhesive bonding and/or painted on.
8. The conveying apparatus as claimed in claim 3, wherein the feature or the feature combination comprises cutouts, elevations or/and edges.
9. The conveying apparatus as claimed in claim 8, wherein the cutouts comprise holes or/and grooves.
10. The conveying apparatus as claimed in claim 3, wherein the feature or the feature combination at least partially consists of light.
11. The conveying apparatus as claimed in claim 3 having a control apparatus which is set up to capture the length of the extents of the feature or of the feature combination for determining the position and the location of the first conveying unit relative to the second conveying unit.
12. The conveying apparatus as claimed in claim 11, wherein determining the position and the location comprises determining the extents of the feature or of the feature combination in a camera image.
13. The conveying apparatus as claimed in claim 11, wherein the control apparatus is set up to record a calibration value for the camera for determining the position and the location.
14. The conveying apparatus as claimed in claim 11, wherein the control apparatus is set up to compare the length of the extent in the direction of travel and the length of the extent perpendicular to the direction of travel of the feature or of the feature combination to reference values.
15. The conveying apparatus as claimed in claim 11, wherein the control apparatus is set up for determining the position of the two conveying units with respect to one another comprises determination of the distance of the two conveying units with respect to one another, a relative position of the two conveying units along a direction of conveyance or/and an angle of the conveying units.
16. The conveying apparatus as claimed in claim 3 wherein the first conveying unit and the second conveying unit each comprises a carrying side located opposite the ground rollers, the carrying unit of the first conveying unit and the carrying side of the second conveying unit being used to jointly carry a single laden or unladen load carrier.
17. A method of controlling conveying units in a conveying apparatus comprising the steps of: providing a feature or feature combination on a first conveying unit; providing a camera on a second conveying unit; angling the camera on the second conveying unit to capture the feature or feature combination on the second conveying unit; setting a reference point based on an initial capturing of the feature or feature combination by the camera; moving one or more of the first conveying unit or the second conveying unit; and determining a distance between the first conveying unit relative to the second conveying unit, and an angle of travel between the first conveying unit relative to the second conveying unit, after movement has begun based on the reference point and continued capture of the feature or feature combination by the camera.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) The invention will now be explained in more detail with reference to the drawings, in which:
(2) FIG. 1 shows a schematic side view of a conveying unit of an embodiment of a conveying apparatus according to the invention;
(3) FIGS. 2A, 2B show a schematic top view of the conveying apparatus of FIG. 1 in a basic state, and an associated camera image;
(4) FIGS. 3A, 3B show a schematic top view of the conveying apparatus of FIG. 1 in a state of the two conveying units in which they are displaced in parallel fashion, and an associated camera image;
(5) FIGS. 4A, 4B show a schematic top view of the conveying apparatus of FIG. 1 in a state having a reduced distance between the two conveying units, and an associated camera image;
(6) FIGS. 5A, 5B show a schematic top view of the conveying apparatus of FIG. 1 in a state having a changed alignment of the two conveying units, and an associated camera image;
(7) FIGS. 6A, 6B show a schematic top view of the conveying apparatus of FIG. 1 in a state having a changed alignment of the two conveying units, and an associated camera image;
(8) FIGS. 7A, 7B show a schematic top view of a conveying unit according to the invention having a projection device; and
(9) FIGS. 8A-8F show different embodiments of a feature of a conveying unit.
DETAILED DESCRIPTION OF THE PRESENT INVENTION
(10) While this invention is susceptible of embodiment in many different forms, there is shown in the drawings and will herein be described in detail one or more embodiments with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to the embodiments illustrated.
(11) FIGS. 1 and 2A show a conveying apparatus 10 having a first conveying unit 12 and a second conveying unit 14. The conveying units 12, 14 are illustrated merely schematically and can be adapted in terms of their dimensions and housing shapes to the application purpose. One possible embodiment makes provision for a configuration in the manner of conveying skids having an outer contour, for example in the form of a fork of a forklift. It is possible by way of the conveying apparatus 10 to convey laden or unladen load carriers, such as for example Euro-pallets. The conveying units 12, 14 communicate with one another and/or with a central controller (not shown), which coordinates the conveying process, in a manner known per se.
(12) As is shown in FIGS. 1 and 2 by way of example with reference to the conveying unit 14, the conveying units 12, 14 have a housing 16 having a carrying side 18 and an undercarriage, which can be displaced on a ground 22 on ground-level rollers 20. The conveying units 12, 14 are configured such that the carrying side 18 can be raised and lowered with respect to the ground 22. If the conveying units 12, 14 adopt a lowered state, the conveying apparatus 10 is in an empty configuration and can maneuver to below a load carrier. Once below a load carrier, the conveying apparatus 10 can raise the carrying sides 18 of the conveying units 12, 14 and thus pick up the load carrier, convey it and set it down again.
(13) As shown in FIG. 2A, the two conveying units 12, 14 in each case have longitudinal axes F, G in the directions of travel H, I. In the case of a rectilinear continuous movement of the conveying units 12, 14, the longitudinal axes F, G coincide with the respective directions of travel H, I of the conveying units 12, 14. The conveying units 12, 14 of the conveying apparatus 10 in the present case are equipped with a device for determining the position and the location of the first conveying unit 12 relative to the second conveying unit 14. The device comprises a camera 24 at the first conveying unit 12 and a feature 26 at the second conveying unit 14.
(14) The feature 26 at the second conveying unit 14 for example consists of an H-shaped basic shape and has a section 28 in the direction of travel H, a shorter section 30 perpendicular to the direction of travel H, and a longer section 32, likewise perpendicular to the direction of travel H. The section 28 in the direction of travel H extends along an axis Z, the sections 30, 32 perpendicular to the direction of travel H extend parallel to an axis Y. In the illustrated embodiment of the conveying apparatus 10, the feature 26 is arranged in the vicinity of an end of the second conveying unit 14.
(15) As can be seen in FIG. 2A, the first conveying unit 12 has a camera 24, which is connected to a control apparatus 25. The control apparatus can be arranged as shown in FIG. 2A in one of the two conveying units 12, 14, for example the first conveying unit 12. Alternatively, the control apparatus 25 can also be part of a central control apparatus (not shown). The transmission of the camera signals to a central control apparatus could be done, for example, wirelessly.
(16) The arrangement of camera 24 and feature 26 can be, as shown in FIG. 2A, divided over a first conveying unit 12 and a second conveying unit 14, i.e. the first conveying unit 12 carries the camera 24 and the second conveying unit 14 carries the feature 26. Alternatively, each conveying unit 12, 14 can carry both a camera 24 and a feature 26. In this case, both the camera 24 and the feature 26 could be arranged on the same side of the housing 16. This would permit simultaneous use of both cameras and the respectively opposite features. However, the camera and feature could also be provided on two different sides of the housing 16 of the conveying unit. This would permit the manufacture of identical conveying units which, depending on their relative state, can sometimes function as a camera-carrying conveying unit and sometimes as a conveying unit carrying identifiers. In this way, it would also be possible to couple more than two conveying units in parallel ad hoc, as long as the corresponding control algorithms are available.
(17) In the case of coordination of the first conveying unit 12 and the second conveying unit 14, provision may for example be made for the first conveying unit 12 to act as the determinant conveying unit and for the second conveying unit 14 to be subject to the first one, and for the traveling behavior of the second conveying unit 14 to be specified by the first conveying unit 12.
(18) The camera 24 in the embodiment 10 shown is attached approximately centrally at the first conveying unit 12 and aligned with the feature 26 of the second conveying unit 14 such that a camera axis A, which represents the optical axis of the camera 24, encloses an angle of approximately 45 with the axis Z. Both the arrangement of the feature 26 at the second conveying unit 14 and that of the camera 24 at the first conveying unit 12 are dependent on the respective type of use and configuration of the conveying apparatus 10. By way of example, the feature 26 can be arranged centrally, and the camera 24 can be arranged at an end. It is likewise feasible to arrange the camera 24 and the feature 26 centrally or at the end. To this end, the feature 26 can be integrated in the housing 16 of the second conveying unit 14 such that the angled arrangement between feature 26 and camera 24 also comes about if camera 24 and feature 26 are arranged directly opposite one another.
(19) Furthermore, FIG. 2A defines both a distance B between the two conveying units 12, 14 in the form of the distance between the central axes F, G of the two conveying units 12, 14 and a horizontal offset . In the starting state shown, the distance is B=B.sub.0, the horizontal offset is .sub.0=0. It is also possible to select a reference horizontal offset .sub.0 that is not equal to 0.
(20) FIG. 2B shows a camera image 34 by the camera 24, as results from the arrangement shown in FIG. 2A. The camera image 34 shows an image 36 of the feature 26, as is formed on a camera sensor of the camera 34 in the starting state, shown in FIG. 2A, and is captured and possibly processed further by the control apparatus 25. The image 36 has a horizontal pixel number P.sub.x and vertical pixel numbers P.sub.y1 and P.sub.y2, to which an extent L.sub.x in the direction of travel H and extents L.sub.y1 and L.sub.y2 perpendicular to the direction of travel H can be assigned. The extent L.sub.x in the direction of travel H here substantially corresponds to the length of the section 28 of the feature 26, as shown in FIG. 1. In the image 36 shown in FIG. 2B, this section is identified as a horizontal section 38. The extent L.sub.y1 perpendicular to the direction of travel corresponds to the length of the section 30 of the feature 26 (see FIG. 1) and is identified in the image 36 as the section 37. The extent L.sub.y2 corresponds to the length of the section 32 of the feature 26 (see FIG. 1) and is identified in the image 36 as the section 39. What can be seen here is that the different lengths of the sections 30, 32 of the feature 26 transform into identical lengths of the sections 37, 38 of the image 36. The presence of identical lengths in the sections 37, 39 of the image 36 is not necessary, however, but merely illustrates the transformation process.
(21) The image 36 is located within the camera image 34 at a position that can be defined by the distances x.sub.1, x.sub.2, y.sub.1 and y.sub.2.
(22) The starting state shown in FIG. 2A gives the reference or control image 34 shown in FIG. 2B, which can be characterized by way of the following relationships:
(23)
(24) The relation L.sub.x0=2L.sub.y10=2L.sub.y20 in FIG. 2B is selected randomly and should be understood to be no more than an exemplary embodiment. The selection of twice the width L.sub.x0 of the feature compared to its heights can of course be adapted to the respective case of application and the respective conditions. The same applies to the relationship L.sub.y10=L.sub.y20, as already explained above. Neither is a central positioning in accordance with y.sub.1=y.sub.2; x.sub.1=x.sub.2 absolutely necessary in the reference image. Of course, other relationships are also possible here, the equality merely symbolizes the ideal starting state.
(25) These values and relationships demonstrate the fact that both conveying units 12, 14 are aligned parallel with respect to one another, have an starting distance B.sub.0, and a horizontal offset .sub.0 is equal to zero. The quotient Q.sub.1/2=L.sub.x/L.sub.y1/2 represents a criterion for the parallelism of the two conveying units 12, 14. A deviation of one or both quotients Q.sub.1/2 from the value Q.sub.0 characterizes an angled relationship of the axes F, G of the two conveying units 12, 14 relative to one another.
(26) FIGS. 3A and 3B show a state that differs from the starting state shown in FIG. 2A. In the state illustrated in FIG. 3A of the two conveying units 12, 14, the alignment of the two conveying units 12, 14 is again parallel, and the distance B between the two conveying units 12, 14 is again B.sub.0. However, the horizontal offset is now not equal to the reference value .sub.0, in particular >0. Such a situation can result, for example, in the case of an approaching movement of the first conveying unit 12 to the second conveying unit 14. In the camera image 34, the state of the two conveying units 12, 14 is imaged as follows: the dimension L.sub.x is unchanged: L.sub.x=L.sub.x0. The location of the image 36, however, has changed: x.sub.1x.sub.2, in particular x.sub.1>x.sub.2. The distance B which has remained the same is shown in L.sub.y1/2=L.sub.y10=L.sub.y20, the parallelism which has remained the same in Q.sub.1/2=Q.sub.0. It is thus possible by way of the camera 34 to determine, on the basis of a previously determined starting image or reference image, the distance between the two conveying units 12, 14 along a direction of travel H, I on the basis of a horizontal offset of the image 36. Analogously, a raising or lowering of the second moving unit 14 with respect to the first moving unit 12 could also be determined on the basis of a vertical offset of the camera image 36. Of course, any desired superpositions of the two movements mentioned can also be determined on the basis of corresponding offsets of the image 36 in the camera image 34.
(27) In the state of the two conveying units 12, 14, shown in FIGS. 4A and 4B, a parallel alignment is again maintained, i.e. Q.sub.1/2=Q.sub.0. For the relative position of the two conveying units 12, 14, =.sub.0=0. Consequently, the image 36 is without offset in the camera image 36. However, for the distance B between the two conveying units: BB.sub.0, in particular B<B.sub.0. The distance between the two conveying units 12, 14 has thus decreased. This is demonstrated in the camera image 34 illustrated in FIG. 4B as an image 36 of the feature 26 which is enlarged in the horizontal and vertical direction: L.sub.x>L.sub.x0;L.sub.y1>L.sub.y10;L.sub.y2>L.sub.y20. It is thus possible, on the basis of the camera image, for the relative distance between the two conveying units 12, 14 to be determined as related to a previously determined starting or relative position on the basis of an undistorted enlargement of the image 36 in the camera image 34.
(28) FIG. 5A shows a state of the two conveying units 12, 14, in which both an angle deviation of the two longitudinal axes F, G of the conveying units 12, 14 compared to the starting or reference state shown in FIG. 2A and also a reduction in the distance between the two conveying units 12, 14 has taken place. For illustration purposes, an angle between the longitudinal axis F of the second conveying unit 14 and an axis G, plotted parallel to the longitudinal axis G of the first conveying unit, is defined in FIG. 5A. The illustrated case 0, in particular here <0, is shown in the camera image 34 by the camera 24, illustrated in FIG. 5B, as follows: L.sub.x>L.sub.x0;L.sub.y1>L.sub.y10;L.sub.y2>L.sub.y20. In particular, the change in the lengths L.sub.y1/2 of the images 37, 39 of the two sections 30, 32 which are arranged perpendicular to the direction of travel H differs. Consequently, for the quotients Q.sub.1/2: Q.sub.1/2<Q.sub.0. In particular, the quotient Q.sub.1=L.sub.x/L.sub.y1 for the length of the section 37 of the image 36 differs from the quotient Q.sub.2=L.sub.x/L.sub.y2, in which: Q.sub.1>Q.sub.2. Consequently, it is possible, on the basis of the changes in the absolute length units L.sub.x, L.sub.y1/2 of the image 36 of the feature 26, to deduce a change in the distance between the two conveying units 12, 14, and by way of the quotients Q.sub.1/2 to deduce a possible change in the angle , which is enclosed by the two longitudinal axes F, G of the two moving units 12, 14.
(29) FIG. 6A shows a state of the two conveying units 12, 14 which is comparable to FIG. 5A, but here a change in the angle between the two conveying units 12, 14 with opposite signs has taken place. Here: >0, and as a result: L.sub.x<L.sub.x0;L.sub.y1<L.sub.y10;L.sub.y2<L.sub.y20. At the same time, for the quotients Q.sub.1/2: Q.sub.1/2>Q.sub.0, in particular
(30)
Consequently, it is possible to ascertain the direction of the angle change on the basis of the changes in the length dimensions of the feature image 36.
(31) FIGS. 7A and 7B show an embodiment of a conveying unit 112. Similar and comparable properties of the embodiment are designated by reference signs which are increased by 100. The conveying unit 112, like the previously described conveying units 12, 14, can be coupled with a further conveying unit to form a conveying apparatus. In addition to the already described properties, such as for example housing, rollers, control apparatus 125 and camera 124, the conveying unit 112 also has a projector 127. The projector 127 is designed to project a feature 216 along a projection axis C into the environment of the conveying unit 112. The projection axis C can here advantageously lie in one plane with the camera axis A. The projection can here be an imaging process for generating the feature 126 and thereby emit a beam bundle which is divergent in principle. This can also be, for example, a scanning process of an individual light point, in which the light point is guided over the surface onto which it is incident along a specified track. Alternatively, it can be a plurality of light beams which make up the feature 126 and are guided parallel with respect to one another, as is schematically illustrated in FIG. 7A.
(32) The feature 126 is projected onto a surface 115 by way of the projector 127. The surface can be a housing of an adjacent conveying unit, i.e. a moving surface. Alternatively, the surface 115 can also be a wall, i.e. a locationally fixed surface, in relation to which the conveying unit 112 is intended to be navigated.
(33) A change in a distance B of the conveying unit 112 from the surface 115 can have an influence on the size of the feature 126. In the case of a parallel projection, as shown in FIG. 7A, the size of the feature 126 on the surface 115 remains. In an imaging process, the feature 126 itself on the surface increases in size with increasing distance B. In addition, an increasing distance B reduces the size of the image 36 of the feature 126, as was already explained above with reference to FIGS. 4A-6B. By way of a suitable selection of the objective lens of the camera 124 and a suitable divergence of the projection, it is also possible here to ascertain from the size of the image 36, as shown in FIG. 7B, the distance B and a changed angle between the surface 115 and the conveying unit 112.
(34) FIGS. 8A-F show different variations of the feature to be captured at the second conveying unit 14.
(35) FIG. 8A illustrates the feature 26 already shown in FIG. 1. What has proven particularly advantageous in the configuration of the feature 24 in FIGS. 1 and 8A is the unequal height of the sections 30, 32 perpendicular to the direction of travel. The lengths of these sections are chosen such that the image 36 of the feature 26 in the case of the ideal starting or reference state for the two sections shows the same length perpendicular to the direction of travel.
(36) Similar features are shown in FIGS. 8B and 8C. By contrast to the feature 26 in FIG. 8A, the features in FIGS. 8B and 8C are not contiguous, but are made up of mutually separate parts and thus form a feature combination. The feature combination 40 in FIG. 8B is split in two, the feature combination 42 in FIG. 8C is split in three.
(37) The situation is similar for the features of FIGS. 8D and 8E. Here, the feature components of the feature combinations shown are formed as circular cutouts in the housing 16 of the conveying unit 14. In FIG. 8D, the feature combination 44 provides two circular cutouts 46, 48. The extent of the feature combination perpendicular to the direction of travel is here realized by way of the diameter of the cutouts 46, 48, the extent in the direction of travel likewise by way of the diameter, but also by way of the position of the cutouts 46, 48. By contrast, in FIG. 8E, the extents of the feature combination 50 in the direction of travel and perpendicular to the direction of travel are determined exclusively by way of the position of cutouts 52, which can be designed for example as holes.
(38) In the embodiment shown in FIG. 8F, features of the housing which are already present in any case, such as for example a wheel cutout 56 or/and a servicing access 58, are used as feature combination 54.
(39) It is to be understood that additional embodiments of the present invention described herein may be contemplated by one of ordinary skill in the art and that the scope of the present invention is not limited to the embodiments disclosed. While specific embodiments of the present invention have been illustrated and described, numerous modifications come to mind without significantly departing from the spirit of the invention, and the scope of protection is only limited by the scope of the accompanying claims.
