Method and device for determining the position of an object

Abstract

With a view to a particularly precise determination of the position (P) of an object (1) using structurally simple means, a method for determining the position (P) of an object (1) with respect to a relative movement between the object (1) and a path (2) is designed and further developed, wherein a detector is arranged on or integrated into the object (1), wherein several markers (3) each having individual position information are arranged sequentially along the path (2) at a predetermined distance and at a predetermined angular position to each other, thus forming a predetermined arrangement, and wherein the detector receives one or more images containing image information of one or more markers (3) to determine the position (P) of the object (1) depending on the individual position information of the respective markers (3), as described below.that, in the event that the detector detects a relative arrangement of two consecutive markers (3) that deviates from the specified arrangement of markers (3), their relative position (P) to each other with respect to distance, angular position and / or lateral offset is determined and taken into account in the position determination. Furthermore, a corresponding device for determining the position (P) of an object (1) is specified.

Description

[0001] The invention relates to a method for determining the position of an object with respect to a relative movement between the object and a path, wherein a detector is arranged on the object or integrated into the object, wherein along the path a plurality of markers, each having individual position information, are arranged one after the other at a predetermined distance and in a predetermined angular position to one another and thus to form a predetermined arrangement, and wherein the detector records one or more images containing image information from individual or multiple markers to determine the position of the object depending on the individual position information of the respective markers.

[0002] Furthermore, the present invention relates to a device for determining the position of an object with respect to a relative movement between the object and a path, in particular for carrying out the above method, wherein a detector is arranged on the object or integrated into the object, wherein along the path a plurality of markers, each having individual position information, are arranged one after the other at a predetermined distance and in a predetermined angular position to one another and thus to form a predetermined arrangement, and wherein the detector is designed to record one or more images containing image information of individual or multiple markers for determining the position of the object depending on the individual position information of the respective markers.

[0003] Methods and devices of the type mentioned above are known in practice and exist in various embodiments. For example, a driverless transport system can be guided along a predetermined path, with such a transport system—an object—being assigned a detector in the form of a camera, which records markers in the form of codes arranged one after the other along the path in a predetermined arrangement. Based on the known predetermined arrangement and individual position information of such markers, the position of the transport system relative to the path and thus within a system in which the path is installed can be determined.

[0004] To implement the specified arrangement, the codes are typically arranged along the path using code tapes. On these code tapes, the codes are arranged one after the other in the specified order, usually allowing for a reliable determination of an object's position.

[0005] However, problems can arise when arranging the code strips in the area of ​​desired curves along a path, as well as in the area of ​​expansion joints on a floor. In these cases, the desired standard and regular spacing between two consecutive codes can often no longer be maintained. In the case of a curve, an additional angular change in the usual arrangement of the codes inevitably occurs. Furthermore, a transverse offset can also occur when arranging two consecutive codes. Such deviations from the specified arrangement can lead to ambiguities and / or inaccuracies in determining the position of the object and thus, for example, in guiding an object along the path.

[0006] The present invention is therefore based on the object of specifying a method and a device for determining the position of an object, according to which a particularly accurate determination of the position of the object is possible using structurally simple means.

[0007] According to the invention, the above object is achieved by a method having the features of claim 1 and by a device having the features of claim 13.

[0008] According to this, the method for determining the position of an object according to claim 1 is designed and developed in such a way that, in the event of a detection of a relative arrangement of two consecutive markers to one another that deviates from the predetermined arrangement of the markers, the detector determines their relative position to one another with regard to distance, angular position and / or transverse offset and takes this into account in the position determination.

[0009] Furthermore, the device for determining the position of an object according to claim 13 is designed and developed in such a way that the detector is designed to determine, in the event of a detection of a relative arrangement of two consecutive markers to one another that deviates from the predetermined arrangement of the markers, their relative position to one another with regard to distance, angular position and / or transverse offset and to take this into account in the position determination.

[0010] In accordance with the invention, it was first recognized that the above object can be achieved in a surprisingly simple manner through skilful evaluation of the data and / or image information recorded by the detector. Specifically, if a relative arrangement of two consecutive markers deviates from the predetermined arrangement of the markers, the detector determines their relative position to one another. To do this, the detector determines the distance between the markers and / or the angular position or the angular attitude of the markers relative to one another and / or any possible transverse offset between the markers. In a particularly simple situation, therefore, only the distance or only the angular position / angular attitude or only the transverse offset is determined, or only two of these three parameters.These specific values ​​are then taken into account when determining the position of the object, so that an accurate and unambiguous determination of the position of the object is possible.

[0011] Consequently, the method according to the invention and the device according to the invention for determining the position of an object provide a method and a device according to which a particularly accurate determination of the position of the object is possible using structurally simple means.

[0012] Depending on requirements, the relative position of the consecutive markers in terms of distance, angular position, and / or transverse offset can be determined during a relative movement and / or without relative movement between the object and the path. Particularly when guiding an object designed as a transport vehicle along the path, the determination can be performed during the relative movement between the object and the path in order to always obtain the most current position value of the object. However, the determination can also be performed when the relative movement is at a standstill, for example, to obtain a starting point for a relative movement or an end point for a relative movement.

[0013] For a particularly precise determination of the object's position, the detector can easily detect a relative arrangement of two consecutive markers that deviates from the specified arrangement by taking one or more images, which of the two consecutive markers both have in common. Various image analysis methods can be used to determine the position, with a single image being sufficient for the determination. When taking multiple images, a suitable image can be selected, or the results from the multiple images can be averaged to enable a particularly precise and reliable position determination.

[0014] Specifically, the two consecutive markers can be recorded together in a detector window. Depending on the requirements, a recorded image can be taken from the entire window or a defined part of it. Using a defined part of the window, for example, can reduce the computational effort required for the determination, since a part of the window typically contains fewer image data points than the entire window.

[0015] To create a particularly compact device, the detector can have a - preferably integrated - evaluation device for evaluating and / or processing data and / or image information recorded by the detector, for example, individual position information. In this case, a compact unit comprising the detector and evaluation device can be realized. Alternatively, such an evaluation device can be assigned to the detector, whereby the evaluation device can be arranged in the immediate vicinity of the detector or remotely from the detector. In this case, the evaluation device can be implemented as an additional device, for example, a computer. This assignment offers the advantage that if a defect occurs in the detector or in the evaluation device, only one component, namely the detector or the evaluation device, needs to be repaired or replaced.Particularly in the case of an integrated design, it is often necessary to replace the entire component comprising the detector and evaluation device, whereby the component that may still be functional - the detector or the evaluation device - must also be replaced despite its still being functional.

[0016] Furthermore, for particularly precise determination of the object's position, data on the position of the two markers, determined in terms of distance, angular position, and / or transverse offset, can be stored in a memory. This allows recorded data to be retrieved at a later time, for example, if there is uncertainty as to whether a current measurement is correct.

[0017] In a further particularly advantageous manner, the storage can be cloud storage or have cloud storage. Such storage offers the possibility of access by different users in different locations.

[0018] Furthermore, the stored data can be used specifically for further relative movement processes between the object and the path to determine the position of the object relative to the path and / or to determine a relative speed between the object and the path. This allows for particularly precisely planned and executed movement processes and a relative speed to be determined with particular accuracy, even in areas where the specified marker arrangement deviates.

[0019] In a further particularly advantageous manner, the stored data can be exchanged between detectors of one or more additional objects, or the stored data can be made accessible to multiple detectors of different objects. For example, a detector that has not yet passed a point on the path with a deviation from the specified arrangement can use data, image information, or a position determination recorded or determined by another detector that has already passed the point for its own determination of the object's position and / or movement guidance along the path.

[0020] Furthermore, an image and / or a map of a system containing the object and the path can be conveniently generated using recorded data of the position or positions of the two or respective markers determined in terms of distance, angular position and / or transverse offset. Such an image or map can comprise a complete system layout and can be used to plan the movements of one or more objects in the system. Furthermore, using such recorded data of the position or positions of the two or respective markers determined in terms of distance, angular position and / or transverse offset - alternatively or additionally - a preferably interpolated trajectory curve can be generated, which can be output or provided instead of position information or position information of one or more markers.This provides an advantage in that one or more curves are not traversed by an object moving relative to the path, for example a vehicle, in a square manner or with corners, but can be traversed in a preferably continuous and circular movement without corners.

[0021] For particularly precise and reliable determination of an object's position, the marker can contain a code, such as a data matrix code, QR code, or barcode. Such codes have proven particularly suitable in practice and offer a particularly wide range of customizable information content.

[0022] In a specific and industrially significant embodiment, the object can be a transport system or vehicle and / or be associated with a transport system or vehicle. However, other applications for the method and device according to the invention are also conceivable.

[0023] Embodiments of the method and the device according to the invention can be used for kink detection in code tapes in positioning systems.

[0024] Furthermore, the implementation examples allow for automatic determination of a system layout. Intermediate positioning or positioning in spaces between adjacent markers that deviate from the specified arrangement or between code bands can be improved, and corresponding ambiguities can be avoided.

[0025] Within the scope of further embodiments, code tape joints can be automatically examined for position and angle using the detector. The information obtained from this can be stored. This information can be transmitted to a central location, for example, a cloud, and retrieved from there if the relevant location is detected by the detector for the first time. A known or determined relationship between two code tape pieces or between two consecutive markers can provide a particularly homogeneous and precise position indication in a corresponding gap. Ambiguities at joints can be avoided, and a more homogeneous and precise route can be achieved.

[0026] There are now various possibilities for advantageously embodying and developing the teaching of the present invention. Reference is made, on the one hand, to the dependent claims and, on the other hand, to the following explanation of preferred embodiments of the method according to the invention and the device according to the invention with reference to the drawing. In conjunction with the explanation of the preferred embodiments with reference to the drawing, generally preferred embodiments and developments of the teaching are also explained. The drawing shows: Fig. 1 shows a plan view of an embodiment of an arrangement of markers in the form of codes on a code tape, Fig. 2 shows a plan view of an embodiment of two code bands arranged relative to each other to form a curve of the type shown in Fig. 1 shown species, Fig. 3 in a plan view an explanation for the following Fig. 4 to 10 shown relative arrangements of code bands, Fig. 4 shows a plan view of an embodiment of two code bands arranged relative to each other with an expansion joint formed therebetween, Fig. 5 shows a plan view of an embodiment of two code bands arranged relative to each other with an expansion joint formed therebetween and a missing code, Fig. 6 shows a plan view of an embodiment of two code bands arranged with an expansion joint formed therebetween and with a transverse offset relative to each other, Fig. 7 shows a plan view of an embodiment of two code bands arranged with an angle change, with an additional distance and with a transverse offset relative to each other, Fig. 8 shows a plan view of an embodiment of a curve formed by two code bands arranged relative to one another, with a position of an object, Fig. 9 shows a plan view of the arrangement according to the embodiment of Fig. 8 with the angle and relative position of two markers adjacent to each other in the curve and Fig. 10 shows a plan view of the arrangement according to the embodiment of Fig. 8 with a division into three areas created by lines.

[0027] Fig. 1 shows a top view and schematically an object 1 at a position P, wherein the object 1 can move along a path 2. According to the embodiment shown here, an arrangement of markers 3 with codes 4 is arranged on a code tape.

[0028] This and the exemplary embodiments of methods for determining the position of an object 1 described below are all based on markers 3 with codes 4. The codes 4 are embodied as data matrix codes 4 by way of example. This is not to be considered restrictive, but merely exemplary. Other codes, such as QR codes and barcodes, can also be used in the same way. Other types of codes are conceivable.

[0029] In positioning systems or positioning devices with which embodiments of inventive methods for determining the position P of an object 1 can be implemented, a position P relative to markers 3 on a code tape is determined. This is generally done using the content of at least one marker 3 and the position of the marker 3 within the viewing window of a detector or sensor. Typically, the relative position of the viewing window center to the code is determined. The relative position is added to the content of the marker 3. Fig. 1 shows an example.

[0030] In general, especially when laying markers 3 or code tapes on a floor or subsurface to form a path 2, but also with electric overhead conveyors, EHBs, curves are necessary. Fig. 2 shows a plan view of an embodiment of two code bands arranged relative to each other to form a curve along a path 2 of the type shown in Fig. 1 shown type with markers 3 having codes 4 in the form of data matrix codes.

[0031] Since the code tapes with the markers 3 are not very flexible, they cannot be applied bent in a radius and must be cut and then applied in individual segments.

[0032] Another possible aspect is cutting the code tape at so-called expansion joints or switches. Here, too, the fixed grid of the markers 3 is not always guaranteed, but the angle is usually maintained.

[0033] The following Fig. The symbols used in the codes 3 to 10 are to be understood as follows: The codes 4 are arranged at a predetermined distance from each other so that they can be decoded reliably. This distance is shown in white. Fig. 3, the Code 4 itself is shown as a black square with a number that reflects the position it contains. As an explanation for the representation chosen here, this Code 4 is shown in the right area of ​​the Fig. 3 is indicated as a data matrix code. The surrounding frame represents the grid in which the codes 4 are arranged. This grid comprises a single marker 3. One embodiment uses 15 x 15 mm codes 4 with a distance or gap of 5 mm between them, which corresponds to a grid of 20 mm.

[0034] Typical exemplary arrangements and relations are shown in the next Fig. 4 to 10 shown.

[0035] Fig. 4 shows a plan view of an embodiment of two code bands with markers 3 and codes 4 arranged relative to one another with an expansion joint 5 formed therebetween.

[0036] Fig. 5 shows a plan view of an embodiment of two code bands with markers 3 and codes 4 arranged relative to each other with an expansion joint 5 formed therebetween and a missing code.

[0037] Fig. 6 shows a plan view of an embodiment of two code bands arranged with an expansion joint 5 formed therebetween and with a transverse offset relative to each other, with markers 3, codes 4 and a path 2.

[0038] Fig. 7 shows a plan view of an embodiment of two code bands arranged with an angular change, with an additional distance and with a transverse offset relative to each other, with markers 3, codes 4 and a path 2.

[0039] Fig. 8 shows a plan view of an embodiment of a curve formed by two code bands arranged relative to one another, with a position P of an object 1, wherein the position P is shown relative to a code band bending at an angle. If the detector only detects the left part of the code band, it calculates a position P of approximately 12.5 units along the code band. If, however, it only sees the right part of the code band, a position of approximately 13.5 units is determined. If the detector sees both sections, it can calculate a position P somewhere in between, e.g., 13 units. This means that the position cannot and will not be determined unambiguously (12.5 / 13 / 13.5).

[0040] These three scenarios generally all occur when driving over the bend or curve. Since the position value along the code band undergoes several jumps here, this can significantly disrupt the control of an object 1, such as a vehicle, moving along path 2. Speed ​​calculation is also not possible in this case.

[0041] Once the detector has completely identified the joint, i.e., decode markers 3 with the numbers 12 and 13 in one image, it can determine the relative position between codes 4 and the angle. With a normal arrangement, the relative position in the tape direction always corresponds exactly to the code grid, perpendicular to the tape direction is always 0, and the angle is also always 0. A deviation or deviations from this constellation indicate that there is a deviating joint or a deviation from the specified arrangement of, for example, markers 3 regularly and equally spaced along a code tape.

[0042] Fig. 9 shows a plan view of the arrangement according to the embodiment of Fig. 8 with the angle and relative position of two adjacent markers 3 in the curve. Are the relative positions of the markers 3 to each other, which are Fig. 9 is formed by the distance and can basically be composed of distance and transverse offset, and the angle is known, can be calculated as in Fig. 10 the position can be clearly determined.

[0043] There are several methods for treating the joint. One example is described here.

[0044] Fig. 10 shows a plan view of the arrangement according to the embodiment of Fig.8 with object 1, markers 3, each with a code 4, and a division into three areas created by three lines. The three lines separate areas where the position is calculated. In the right area, the position is calculated based on the right-hand piece of code tape, in the left area on the left piece of code tape, and in the lower area, interpolation takes place between the areas. This means there are no longer any overlapping areas in which two different position values ​​can be output depending on visibility. Calculating speed is also much easier in this case, since the actual distance between two position values ​​can be determined.

[0045] A possible implementation to realize the central point of the idea would be to virtually add mark 13 if only mark 12 was read. After that, the calculation can be performed as for the visibility of both.

[0046] Further aspects regarding embodiments of the teaching according to the invention:

[0047] Instead of the rather harsh transition with the three lines described above, a somewhat wider area can also be interpolated. This allows, for example, a smoother ride for object 1 designed as a transport vehicle.

[0048] The algorithm for calculating the position of object 1 can also be used to ensure that marker 3 is missing during the transition.

[0049] It is also possible to cleanly separate a segment stack or stack of code bands and then make ambiguities unambiguous in each constellation.

[0050] An advantageous implementation of the inventive teaching utilizes cloud storage of the constellation between the two code band segments. This allows each detector to contribute to building a map as quickly as possible, while other detectors already have access to constellation information, even if they themselves are seeing a constellation for the first time.

[0051] Using the constellations, a complete virtual representation of the system layout can also be created, for example, in the form of a map. Auxiliary inputs, such as which pieces are at certain angles or in certain positions relative to others, can be provided to the system via a user interface, so that any accumulated errors are less significant.

[0052] Likewise, it would be advantageous, for example, to always assume that code tape pieces with a length of more than 2 m are at an integer multiple of a 45° angle. This allows the algorithm to always lock onto them.

[0053] Embodiments of the present invention show a determination of the relationship between the markers 3 or codes 4 and use this information to improve the positioning or the determination of the position of an object 1.

[0054] Furthermore, a connection to a storage or a cloud can be established in order to exchange the specific or determined information with other detectors.

[0055] With regard to further advantageous embodiments of the method according to the invention and the device according to the invention, reference is made to the general part of the description and to the appended claims in order to avoid repetition.

[0056] Finally, it should be expressly pointed out that the embodiments described above serve only to explain the claimed teaching, but do not limit it to the embodiments. List of reference symbols 1 object 2 path 3 markers 4 Code 5 Expansion joint P Position

Claims

[1] Method for determining the position (P) of an object (1) with respect to a relative movement between the object (1) and a path (2), wherein a detector is arranged on the object (1) or integrated into the object (1), wherein along the path (2) a plurality of markers (3), each having individual position information, are arranged one after the other at a predetermined distance and in a predetermined angular position relative to one another and thus to form a predetermined arrangement, and wherein the detector records one or more images containing image information of individual or multiple markers (3) for determining the position of the object (1) depending on the individual position information of the respective markers (3), characterized bythat in the event of a detection of a relative arrangement of two consecutive markers (3) deviating from the predetermined arrangement of the markers (3), the detector determines their relative position to one another with regard to distance, angular position and / or transverse offset and takes this into account when determining the position. [2] Method according to claim 1, characterized by that the determination of the relative position of the successive markers (3) with regard to distance, angular position and / or transverse offset takes place during a relative movement and / or without relative movement between object (1) and path (2). [3] Method according to claim 1 or 2, characterized by that the detector detects a relative arrangement of two consecutive markers (3) to one another that deviates from the predetermined arrangement by means of a recording of one or more images, which the two consecutive markers (3) both have in common. [4] Method according to one of claims 1 to 3, characterized by that the two consecutive markers (3) are recorded together in a viewing window of the detector. [5] Method according to one of claims 1 to 4, characterized by that the detector has a - preferably integrated - evaluation device for evaluating and / or processing data and / or image information recorded by the detector, for example individual position information, or that such an evaluation device is assigned to the detector. [6] Method according to one of claims 1 to 5, characterized by that data of the position of the two markers (3) determined with regard to distance, angular position and / or transverse offset are stored in a memory. [7] Method according to claim 6, characterized by that the storage is cloud storage or has cloud storage. [8] Method according to claim 6 or 7, characterized by that the stored data are used for further relative movement processes between object (1) and path (2) to determine the position of the object (1) relative to the path (2) and / or to determine a relative speed between object (1) and path (2). [9] Method according to one of claims 6 to 8, characterized by that the stored data are exchanged between detectors of one or more further objects (1) or that the stored data are made accessible to several detectors of different objects (1). [10] Method according to one of claims 1 to 9, characterized by that an image and / or a map of a system comprising the object (1) and the path (2) is generated on the basis of recorded data of the position or positions of the two or respective markers (3) determined with regard to distance, angular position and / or transverse offset. [11] Method according to one of claims 1 to 10, characterized by that the marker (3) has a code (4), for example a data matrix code, QR code or barcode. [12] Method according to one of claims 1 to 11, characterized by that the object (1) is a transport system or vehicle and / or is assigned to a transport system or vehicle. [13] A device for determining the position (P) of an object (1) with respect to a relative movement between the object (1) and a path (2), in particular for carrying out the method according to one of claims 1 to 12, wherein a detector is arranged on the object (1) or integrated into the object (1), wherein along the path (2) a plurality of markers (3), each having individual position information, are arranged one after the other at a predetermined distance and in a predetermined angular position relative to one another and thus to form a predetermined arrangement, and wherein the detector is designed to record one or more images containing image information of individual or multiple markers (3) for determining the position of the object (1) depending on the individual position information of the respective markers (3), characterized byin that the detector is designed to determine, in the event of a detection of a relative arrangement of two successive markers (3) deviating from the predetermined arrangement of the markers (3), their relative position to one another with regard to distance, angular position and / or transverse offset and to take this into account when determining the position.

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