The invention relates to a method and a device for producing and maintaining an assignment of object data of an object to a changing physical position of the object in a sorting device which comprises at least one entry point for feeding objects to the sorting device and a plurality of transfer points at which selected objects can be discharged from the sorting device.
In order to identify an object that has been discharged from a sorting facility, e.g. a sorting conveyor, one can use the sorting data of the objects on the sorting conveyor that are available via the control unit of the sorting conveyor, wherein for example image matching or a comparison of other identification features such as barcodes, etc. can then be carried out. Such assignment is complex. Furthermore, when an object is discharged, the unambiguous assignment between object and position is usually lost, because objects overtake one another or are pushed over one another.
The task of the present invention is to not lose, at any point in time, the assignment between a discharged object and its position during a course of movement of the object following on from the discharge process, and furthermore, in the event that the assignment is lost once, to restore it without substantial effort.
To solve the above problem, the invention proposes a method for producing and maintaining an assignment of the object data of an object to a changing physical position of the object in a sorting device which comprises at least one entry point for feeding objects to the sorting device and a plurality of transfer points at which selected objects can be discharged from the sorting device, with the steps:
In the case of such an identification of an object at a specific transfer point, e.g. of a particular discharge device of a sorting conveyor, advantageous use is made of the fact that an object to be sorted is already identified when it is fed to the sorting conveyor or when it is on the sorting conveyor itself, so that the object can be discharged at a particular transfer point that is assigned to it.
The object data of a particular object preferably comprise at least identity data for the object which can be stored in a higher-level control unit of the sorting device. The identity data may correspond to an identity feature of the object or may be capable of being derived from it. In the course of the process, further data are captured as object data and, expediently, are also stored, in particular the optical object data and at least one current position of the object, in the form of positional data.
Sorting data, from which a sorting destination of a particular object can be derived or which directly describe the sorting destination, can be captured, for example optically, for example by means of a barcode on the object, or may already be stored in the control unit and assigned to the identity data, so that the sorting data can be located on the basis of the identification data. The sorting data can likewise be stored as part of the object data of a respective object.
The sorting device can be any device, facility or system suitable for sorting objects, having at least one entry point and several transfer points for discharging selected objects. For example, it can be a continuous conveyor, e.g. ring sorter, with conveyor units that are equipped with tipping trays, drop-down flaps or transverse conveyor belt elements. On the other hand, it also comprises discontinuous working techniques, such as a sorting system with driverless transport vehicles.
The transfer points can be discharge devices of a sorting or continuous conveyor, to which a delivery path is connected, e.g. in the form of a conveyor, a slide, a roller conveyor and/or a container into which the objects are dropped or thrown. The combination of a transfer point, e.g. a discharge device of a sorting conveyor, with a delivery path following on from it which extends to a removal point and which can be formed, for example, by a removal conveyor, is also referred to as the end point.
A discharge device can for example have a slide, pusher or flipper.
The optical object data of the objects can be captured by at least one camera and/or at least one scanner, in particular a laser scanner.
Tracking comprises determining the position, successively at chronological intervals which can be either fixed, e.g. time intervals of between 0.1 ms and 10 s, or result from other parameters and are not directly predetermined.
When one or more dimensions of the object are captured, optical capture processes can for example be carried out in one, two or all three coordinate directions, e.g. by means of at least one measuring camera, a laser measuring device or by means of light barrier arrangements. In addition or alternatively, one or more images of the object can be taken, and the weight of the object can be recorded, e.g. by means of a weighing device integrated in the area of an infeed belt. The captured data for dimensions, images and/or weight are preferably stored as part of the object data assigned to the object.
It can be envisaged that the object is actively conveyed along the delivery path or moves in an unpowered manner, e.g. slips, rolls or falls.
The repeated positional determinations that are carried out at short intervals within the framework of tracking are, expediently, carried out by means of optical capture of the object, in particular by one or more cameras or scanners, wherein image data or optical tracking data are generated, and by comparing these data with the optical object data that have been previously captured and stored. This comparison can be made with each determination of position, after a certain number of positional determinations, e.g. at every second, fifth, tenth or 100th, at predetermined time intervals, or at any rate at the latest when the object is removed, in order to produce by this point in time at the latest a link or assignment between the previously captured optical object data and/or other object data of the object and the object data captured in the context of tracking, in particular image data, so that by the time of removal at the latest, the object is clearly identified or at least its recipient data can be assigned.
Expediently, the same camera or scanner device is intended for both the acquisition of the optical object data and the repeated optical capture of the object in the context of tracking.
For preference, it is envisaged that a position and/or a time of removal of the discharged object from the removal path is captured and preferably also stored, in particular as a further part of the object data of the object.
The optical object data can be captured at a predetermined time, as an alternative to capture at a predetermined position, or when the object has been discharged from the sorting device at the transfer point.
It is within the scope of the invention that several discharged objects are simultaneously located on the delivery path, and each individual object is tracked. Irrespective of whether tracking is of a single object or of several objects simultaneously, in the context of the invention this means an essentially continuous visual capture and determination of the position of an object or of each individual object at short intervals (e.g. less than 1 ms, 10 ms or 100 ms), so that the position of one or each object on the delivery path is known at any time or, more precisely, at consecutive time points at short intervals. It is sufficient to store the respective last or current position of the object as part of the object data, wherein this can be overwritten by the next current position. The aforementioned time intervals can be so small that the capturing of the position is practically continuous.
Where numerous objects are transferred in rapid succession to one and the same transfer point, it can happen that when an object is tracked, the loss of the assignment of the object data to the physical position of the object may occur at a position along the delivery path, for example because the object is intermittently completely or partially obscured from the view of the image acquisition device or camera that it used for tracking by one or more other objects, or because an object is removed from the delivery path, for example if it falls down from the delivery path or is taken manually, and is then manually replaced on the delivery path, wherein in such a case it is envisaged that after assignment has been lost, tracking is continued as soon as possible, i.e. in particular as soon as the object is no longer obscured from the view of the image acquisition device or has been replaced, in particular in that further optical object data and, expediently, also the physical position of the object are captured and compared with the optical object data, and if the optical object data agree with the further optical object data within the scope of a defined tolerance range, the tracking is continued on the basis of the previously captured optical object data, wherein the tracking comprises repeated successive determinations of the object's position along the delivery path at chronological intervals until the removal of the object, and storage of a current position of the object as a further part of the object data of the object.
In the event of repeated loss of the assignment of the object data to a physical position of the object, the aforementioned steps can be run through again.
If the further optical object data deviate from the optical object data outside a given tolerance range, an error message can be added to the object data.
It can be envisaged that all the objects located within the delivery path between the transfer point and the point of removal are continuously captured and tracked by the tracking system and, in the event of an object being obscured by another object in the delivery path or removal of an object from the delivery path, the tracking of the object is continued as soon as possible, in particular as soon as the object is no longer obscured or has been replaced on the delivery path.
It lies within the scope of the invention that the object data of all objects that are simultaneously located on a delivery path of a transfer point and have not yet been removed are assigned to the transfer point as a subset of all the object data present in the sorting device, and when the further optical object data are compared with the optical object data, the optical object data of the subset of object data assigned to the transfer point are used.
Expediently, the invention envisages that the identity data or object data of an object taken from the delivery path, and/or any information derived from them, are communicated to a person or removal device removing the object. For example, the derived information may be the position of an object in the sequence of a delivery run of a driver of a parcel delivery vehicle, and knowledge of it may enable better loading of the vehicle. An exact storage position in the parcel delivery vehicle can also be communicated. The invention thus advantageously allows that the person or removal device taking an object does not need to determine the identity of the object again, but has the identity data that have already been captured directly available on the basis of the positional tracking of the object, and possibly also further information.
It can be envisaged that at the entry point, e.g. on an infeed device, or on the sorting device itself, the dimensions and/or the weight of an object are recorded and stored as part of the object data, and are communicated to a control unit as needed.
With regard to the device, the object of the invention is achieved by a device for producing and maintaining an assignment of object data of an object to a changing physical position of the object in a sorting device which comprises least one entry point for supplying objects to the sorting device and numerous transfer points at which selected objects can be discharged from the sorting device, and comprises
Further advantages and features of the invention arise from the following description of an embodiment, wherein reference is made to a drawing in which
In the example shown, the sorting conveyor 2 comprises a number of transport units 8a that are moved in a direction of travel 8, each of which is provided with a transverse conveyor belt element that can be driven cross-wise to the direction of travel 8, on which in each case one object can be received, transported and delivered to a specific transfer point or a specific end point. Here, the transfer point 10 is formed by an essentially familiar discharge device.
A central control unit of the sorting system, to which the object data or the initial image data and identity features of each individual object that has been fed in are communicated, at the same time has sorting data for each individual object, from which it is possible to derive to which transfer point or into which end point each individual object located on the sorting conveyor 2 is to be discharged.
Furthermore, on the basis of the known position of the infeed device and the likewise known speed of the sorting conveyor, the control unit continuously receives logical and/or physical positional data for each individual object located on the sorting conveyor, or it can determine them on the basis of the speed of the sorting conveyor, i.e. logical positional data in relation to an assignment of an object to the transportation unit of the sorting conveyor that bears it, and/or physical positional data.
Since the control unit knows the sorting destination of each object on the basis of the aforementioned sorting data, and thus knows the transfer point at which the object is to be discharged, at or shortly before reaching the specific transfer point the control unit can communicate a discharge signal to the sorting conveyor or the transportation unit bearing a specific object, whereupon the transverse conveyor belt element is set into operation and the object is discharged to the specific transfer point 10.
It goes without saying that numerous infeed devices can be provided for feeding objects to the sorting conveyor, and a capture device can be provided at one or more infeed devices, either downstream of the infeed device on the sorting conveyor, as shown in
As
Before, during or after the discharging of an object at the transfer point assigned to it, in this example, the discharge device, the control unit registers the discharged object as an object located at or following on from the specific transfer point, wherein the object data of such objects assigned to a particular transfer point can be stored as a subset of all the object data present in the sorting device. In the example of
Each discharged object is tracked from the transfer point 10 with respect to its position along the delivery path up to of its eventual removal at a removal point 14. This tracking is carried out in an essentially familiar manner, by means of the camera 12 taking a picture of the object at short intervals which may be less than 1 ms or less than 10 ms, and comparing it with an image that has been taken shortly before in each case, from which a current position of the object is determined. Each current position of an object is stored as part of the object data of the object, so that at all times, there is an assignment of the object data of the object and of the position.
The object is tracked by the aforementioned tracking system until it is removed from the delivery path, in particular up to a removal point 14, which can be set up in such a way that each object discharged at the transfer point 10 is regularly removed there. Alternatively, it is possible for an object to be removed from the delivery path at any point along it.
In the tracking of an object, the assignment of the object data to the physical position of the object may be lost as it moves along the delivery path, for example, if the object is briefly obscured by other objects and is not visible or is not fully visible to the camera. For this eventuality, it is envisaged that after the loss of the assignment, further optical object data, in particular image data, of the object are captured, in particular as soon as it is no longer obscured by other objects and becomes visible to the camera again, and that these further optical object data or image data are compared with the original, previously captured optical object data or image data. If agreement is found between the further image data or optical object data and the corresponding previously captured image data or optical object data that lies within a predetermined tolerance range, the tracking of the object can be continued. Here, either the further optical object data can be taken as the basis and stored, e.g. as a further part of the object data, or the tracking can be continued on the basis of the previously captured optical object data.
Since the object data of each object at the end point 10 are stored in the control unit, this information can be used when an object is removed from the end point or the delivery path or removal point, in order for example to transport onwards or store several objects belonging to one sorting destination together, or to remove objects belonging to different sorting points from one and the same delivery path or sampling point, and on the basis of the sorting information that is known for each object, to assign different sorting destinations and to arrange different onward transportation.
This makes it possible to assign several sorting targets to one and the same transfer point and thus save on transfer points or use them several times.
Number | Date | Country | Kind |
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19185901.6 | Jul 2019 | EP | regional |