System for recognizing unstable objects

Abstract

To improve a system for recognizing unstable objects.SOLUTION: A system for recognizing unstable objects placed on a conveyor 10, comprises means 3 for detecting a bottom designed for detecting a shape of the bottom of an object 2 transported.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a system for recognizing unstable objects moving by a conveyor.

[0002] In particular, the present invention relates to a system for recognizing unstable objects conveyed on a sorting machine. [Background technology]

[0003] In the fields of postal, shipping and logistics, systems for sorting objects that need to be moved from an origin to a destination are of particular importance.

[0004] The system comprises a main conveying line which receives the mass of objects to be sorted and distributes them appropriately to various secondary lines which then convey them to the distribution stations for which the individual objects are intended.

[0005] The objects are placed and transported on several conveyor belts or rollers which may be arranged in succession to form a circuit forming the abovementioned main transport line from which secondary lines branch off.

[0006] The success of e-commerce has led to a significant increase in the number of unstable objects that sorting equipment must handle.

[0007] In fact, courier services are now used to deliver a very wide range of products to purchasers, from wallets to home appliances, which means that the use of standardized standards in the manufacture and use of sorting equipment is not effective.

[0008] The term "unstable object" in this context refers to an object that may tip over during transport on the sorting device and impede the sorting operation of themselves or other adjacent objects, or even fall off the conveyor. For example, an oval (elliptical) object placed vertically on a conveyor belt is unstable because its supporting base is relatively narrow in relation to the space it occupies in the space, and its center of gravity is not located close to the base. Similarly, an object with a generally convex shape is less stable because it has less surface area in contact with the conveyor.

[0009] Correct management of labile objects first requires recognition of the labile objects, i.e., identification of the labile objects with respect to the general properties of the objects being sorted.

[0010] Currently, the recognition of unstable objects is carried out by determining their shape and trying to determine the location of their respective centres of gravity. For this purpose, the sorting machines are equipped with scanners that check the shape of the objects being conveyed and with scales to determine their weight.

[0011] While prior art recognition systems are useful, their effectiveness has been shown to be only partial, and sorting system administrators are unable to significantly reduce the human use responsible for non-automated human recognition of unstable objects. Summary of the Invention [Problem to be solved by the invention]

[0012] The technical objective underlying the present invention is to propose a system for recognizing unstable objects, which is able to overcome the above-mentioned drawbacks of the prior art. [Means for solving the problem]

[0013] This technical object is achieved by a system made in accordance with the attached claims.

[0014] Further features and advantages of the present invention will become more apparent in the non-limiting description of preferred, but not exclusive, embodiments of a recognition system, as illustrated in the accompanying drawings, in which: [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is an axonometric view of a sorting system in which a system according to the invention may be installed. [Diagram 2] FIG. 2 is a schematic side view of a conveyor associated with a system for detecting the shape of the bottom of a conveyed object, included in a system according to the invention. [Diagram 3] FIG. 3 is a schematic diagram of the processing of a detected object and its bottom shape. [Figure 4] FIG. 4 is a schematic diagram of the processing of a detected object and its bottom shape. [Diagram 5] FIG. 5 is a schematic diagram of the processing of a detected object and its bottom shape. [Figure 6] FIG. 6 is a schematic diagram of the processing of the workpiece. [Figure 7] FIG. 7 is a diagram of the processing unit. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] With reference to said figures, the reference number 1 indicates a sorting system comprising a system for recognizing unstable objects according to the invention.

[0017] It should be noted that the proposed system is designed to recognize unstable objects placed and transported on a generic conveyor 10, regardless of the type of system in which the object is located.

[0018] However, in the following, for simplicity of explanation, reference will be made to the specific case in which an identification system is used in a sorting device 1, which may also be similar to that described in the description of the prior art.

[0019] The conveyor 10 may have a number of conveying modules 11, on which the objects 2 to be sorted move, which are arranged in succession to form a path, which may, for example, be in the form of a loop or have another configuration.

[0020] The transport modules may each comprise a motor-driven belt 11 closed in a loop and slidable between two linkages or a series of motor-driven rollers.

[0021] In the following, reference is made to the particular case where each module 11 is defined by a motor-driven conveyor.

[0022] Each of the objects 2 to be conveyed rests on and is carried by the belt 11 and therefore has a support base 20 defining at its bottom a support surface which is in contact with the upper surface of the belt 110 .

[0023] According to an important aspect of the invention, the recognition system comprises means for recognizing a bottom 3, configured to detect at least one shape, in particular at least one contour, of a bottom 20 for supporting an object 2 transported on a conveyor 10. The means for recognizing a bottom 3 is shown diagrammatically in Fig. 2. In the example of Fig. 1, the means for recognizing a bottom 3 is accommodated in a housing C.

[0024] In fact, by using the means 3 for recognizing the bottom as described above, the present invention is able to obtain the two-dimensional shape of the bottom surface of each detected object 2, i.e., the two-dimensional shape of the bottom 20 as described above.

[0025] By processing this acquisition, the proposed system is able to establish whether the detected object 2 has a suitable bottom to allow sufficient stability during its transport on the conveyor 10.

[0026] It is also possible that the means for recognizing the bottom are suitable for determining the three-dimensional configuration of the bottom.

[0027] Preferably, said means for recognising the bottom comprise one or more scanning devices 3, which may be of the laser type, for example laser profile sensors such as those of the Wenglor brand or other similar products.

[0028] According to a particular embodiment of the invention, a separation space is formed between one module 11 of the conveyor 10 and the other module 11, for example between two belts 11. The means 3 for recognizing the bottom can then be located below the conveyor 10 and facing the separation space between the two modules 11, so as to detect the shape of the bottom of the object 2 conveyed during its passage from one module 11 to another module 11 (see FIG. 2).

[0029] More specifically, FIG. 2 shows an example where the detection means comprises a profile sensor 3 , indicating both the direction of the laser beam 31 and the viewing angle 32 of the receiver of the sensor 3 .

[0030] According to a possible operation of the means for recognizing the bottom, a scan of the bottom of the object is performed to a depth of a predetermined height, and anything detected in that vertical range is acquired and considered to be the bottom of the object, while anything beyond the scanning depth limit is not acquired and therefore is not considered to be the bottom surface or bottom of the object.

[0031] According to a preferred embodiment of the invention, the system also comprises upper acquisition means 5 arranged to detect parameters relating to the overall shape of the conveyed object.

[0032] According to the example of FIG. 1, the upper acquisition means 5 is arranged downstream of the housing C mentioned above.

[0033] More specifically, the upper acquisition means 5 is set to acquire at least the shape of the detected object as seen from above or below.

[0034] More specifically, the upper acquisition means may comprise a photocell barrier 5 such as the one shown in FIG. 1, or a laser system, or any other device suitable for the purpose.

[0035] Furthermore, the upper acquisition means may also be designed to detect the height, thickness and length of each object 2 .

[0036] Preferably, the system according to the invention comprises a processing unit 4 connected to the means for recognizing the bottom 3 and to the upper acquisition means 5, the processing unit 4 comprising a lower shape module 41 adapted to define at least a flat bottom surface representative of the bottom detected by the means for recognizing the bottom 3. More specifically, said processing can be obtained by providing the processing unit 4 with geometric parameters of the sorting device 1, such as for example the distance between the upper surface 110 of the conveyor 10 of the belt 11 and the means for recognizing the bottom 3. Said information can for example be recorded in a memory module 40 present in the processing unit 4.

[0037] In reality, the flat bottom surface mentioned above is a three-dimensional representation of the bottom of the detected object, for example, if the bottom is a rectangular surface with a depression in the middle, i.e. a concave surface with a rectangular perimeter, and the flat surface contacts the belt, the flat surface will be a rectangular loop.

[0038] It should be noted that, generally speaking, in this description, the processing unit 4 is presented sub-divided into separate functional modules only for the purpose of clearly and completely describing its functionality.

[0039] In practice, the processing unit 4 may be constituted by a single electronic device, also of the type typically present in systems of this type, suitably programmed to carry out the functions described, and the various modules may correspond to hardware units and / or software routines forming part of the programmed device.

[0040] Alternatively or additionally, functions may be performed by multiple electronic devices, whereby the functional modules may be distributed.

[0041] Generally speaking, the processing unit 4 may comprise one or more microprocessors or microcontrollers for executing instructions contained in memory modules, and said functional modules may also be distributed across multiple local or remote computers based on the architecture of the network in which they reside.

[0042] Preferably, the processing unit 4 comprises an upper shape module 42 configured to define an overall planar surface representing the overall contour from below or above of the object detected by the upper acquisition means.

[0043] In reality, the entire flat surface is a three-dimensional surface that constitutes a representation in a horizontal plane of the contour of the object as seen from below or above.

[0044] Furthermore, the processing unit 4 may be configured to obtain shape parameters starting from a flat bottom and a flat overall surface, and may comprise a classification module 400 configured to determine whether the detected object is stable or unstable depending on the fact that one or more of the respective shape parameters are greater or smaller than a relative predetermined discrimination threshold.

[0045] In the following, specific examples of shape parameters are described based on this description and on the modules of the processing unit 4 designed to obtain them.

[0046] The processing unit 4 may comprise a ratio module 43 configured to calculate a first shape parameter related to the ratio of the area of ​​the flat bottom surface to the area of ​​the total flat surface. More specifically, the ratio module 43 may for example calculate a ratio between said two surface areas. More specifically, the first shape parameter is preferably a percentage value of the area of ​​the flat bottom surface with respect to the area of ​​the total flat surface.

[0047] Furthermore, the processing unit 4 preferably comprises a contour forming module 44 configured to define a minimum bounding rectangle 21 of the flat bottom surface and a minimum bounding rectangle 22 of the entire flat surface (see FIG. 3).

[0048] The processing unit 4 may further comprise a centering module 45 configured to determine the geometric center C1 of the minimum bounding rectangle 21 of the flat bottom surface and the geometric center C2 of the minimum bounding rectangle 22 of the entire flat surface. The processing unit 4 may then also comprise a distance module 451 configured to calculate the distance between the geometric centers C1 and C2.

[0049] Further, the processing unit comprises a center ratio module 46 configured to determine the length of the shortest side 23 of the minimum bounding rectangle 22 of the entire flat surface and to calculate a second shape parameter related to the ratio between the distance between the two centers determined by the centering module and the length of the shortest side 23.

[0050] The processing unit may also comprise an axis identification module 47 for identifying, in each of said minimum bounding rectangles, two axes 24, 25, 26, 27 extending from respective centres C1, C2 and terminating at respective peripheries, parallel to the respective lengths and relative widths.

[0051] Therefore, the processing unit may have an axis ratio module 48 configured to calculate a third shape parameter and a fourth shape parameter related to the ratio between the lengths of the above-mentioned axes 24, 25, 26, 27 of the minimum circumscribing rectangle 21 of the flat bottom surface, which has the length of the axis that is angularly closest to the minimum circumscribing rectangle 22 of the entire flat surface.

[0052] The processing unit may further comprise a verticality module 49 configured to calculate a fifth shape parameter related to the ratio between the overall height H of the detected object and the shortest side of the minimum bounding rectangle 21 of the flat bottom surface.

[0053] More specifically, the processing unit may also comprise a packaging module 491 for defining a minimum circumscribing prism 27 of the object to be detected. The total height of the object measured with the perpendicularity module may then be the height H of said minimum circumscribing prism 27.

[0054] According to a preferred embodiment of the present invention, the classification module comprises: a first shape parameter corresponding to a percentage of the area of ​​the flat bottom surface relative to the area of ​​the entire flat surface is less than or equal to a first discrimination threshold; a condition that a second shape parameter corresponding to the ratio between the distance between the two centers determined by the centering module and the length of the shortest side of the minimum bounding rectangle 22 of the entire flat surface is less than or equal to a second discrimination threshold; a third axial parameter and a fourth axial parameter corresponding to the ratio between the lengths of the axes of the minimum bounding rectangle 21 of the flat bottom surface, the minimum bounding rectangle having an axis length that is angularly closest to the minimum bounding rectangle of the entire flat surface, are less than or equal to a third and fourth decision threshold; The detected object is configured to be classified as unstable if at least one of the conditions is verified: a fifth shape parameter corresponding to the ratio of the overall height of the detected object to the shortest side of the minimum bounding rectangle 21 of the flat bottom surface is greater than or equal to a fifth discrimination threshold.

[0055] For example, the first decision threshold may be equal to 20%, the second decision threshold may be equal to 40%, the third and fourth decision thresholds may be equal to 80%, and the fifth decision threshold may be equal to 120%.

[0056] In practice, the shape of each of the objects moving in the sorting device equipped with the recognition system according to the invention is acquired by the detection means, whereby the processing unit obtains a number of parameters which are compared with respective predefined thresholds to obtain an automatic classification of the objects as "stable" and "unstable".

Claims

1. In a system for recognizing unstable objects placed on and transported on a conveyor (10), The system comprises a detection means (3) for detecting the bottom surface, which is designed to detect the shape of the bottom surface of an object (2) being transported.

2. The system according to claim 1, wherein the conveyor (10) has two transport modules (11), an object (2) moves between the two transport modules (11), and a separation space (S) is formed between the two transport modules (11), and the detection means (3) is positioned below the conveyor (10) and opposite the separation space (S) to detect the three-dimensional configuration of the support surface (200) of the object (2) being transported as the object (2) passes from one transport module (11) to the other transport module (11).

3. The system according to claim 2, wherein one or more of the transport modules are equipped with a motor-driven belt (11) that is closed in a loop shape.

4. The system according to claim 2, wherein one or more of the transport modules are equipped with a series of motor-driven rollers.

5. The system according to claim 1, wherein the system comprises a processing unit (4) connected to means (3) for detecting the bottom surface, and the system comprises a module (41) having a lower shape configured to define one or more flat bottom surfaces representing the bottom detected by the upper acquisition means.

6. The system according to claim 1, further comprising an upper acquisition means (5) configured to detect parameters relating to the overall shape of the transported object.

7. The system according to claim 5, wherein the processing unit (4) is connected to the upper acquisition means (5), and the processing unit (4) comprises an upper shape module (42) configured to define an entire flat surface representing the contour of the entire object detected by the upper acquisition means as viewed from below or above.

8. The processing unit (4) is configured to acquire several shape parameters starting from at least the flat bottom surface, The system according to claim 5, wherein the processing unit (4) comprises a classification module (400) configured to determine whether a detected object is stable or unstable based on whether one or more of the aforementioned shape parameters are greater than or less than a relative predetermined identification threshold.

9. The system according to claim 7, wherein the processing unit (4) comprises a ratio module (43) configured to calculate a first shape parameter relating to the ratio of the area of ​​the flat bottom surface to the area of ​​the entire flat surface.

10. The system according to claim 7, wherein the processing unit (4) comprises a contour forming module (44) configured to define the minimum circumscribing rectangle (21) of the flat bottom surface and the minimum circumscribing rectangle (22) of the entire flat surface.

11. The system according to claim 10, wherein the processing unit (4) has a centering module (45) configured to determine the geometric center (C1) of the minimum circumscribing rectangle (21) of the flat bottom surface and the geometric center (C2) of the minimum circumscribing rectangle over the entire flat bottom surface.

12. The system according to claim 11, wherein the processing unit (4) has a distance module (451) configured to calculate the distance between the geometric center (C1) and the geometric center (C2).

13. The system according to claim 12, wherein the processing unit comprises a center ratio module (46) configured to determine the length of the shortest side of the minimum circumscribing rectangle (22) over the entire flat surface and to calculate a second shape parameter relating to the ratio between the distance between two centers determined by the centering module and the length of the shortest side.

14. The system according to claim 10, wherein the processing unit comprises an axis identification module (47) for identifying two axes (24, 25, 26, 27) in each of the minimum circumscribing rectangles (21, 22) that are parallel to their respective lengths and relative widths and extend from their respective centers (C1, C2) and terminate around their respective perimeters.

15. The system according to claim 14, wherein the processing unit has an axis ratio module (48) configured to calculate a third shape parameter and a fourth shape parameter relating to the ratio between the axis lengths of each axis of the minimum circumscribing rectangle (21) of the flat bottom surface, the axis length being angularly closest to the minimum circumscribing rectangle (22) of the entire flat surface.

16. The system according to claim 10, wherein the processing unit has a verticality module (49) configured to calculate a fifth shape parameter relating to the ratio of the total height of the detected object to the shortest side of the minimum circumscribing rectangle (21) of the flat bottom surface.

17. The processing unit (4) is configured to acquire several shape parameters starting from at least the flat bottom surface, The processing unit (4) includes a classification module (400) configured to determine whether a detected object is stable or unstable based on whether one or more of the shape parameters are greater than or less than a relative predetermined identification threshold. The processing unit (4) includes a ratio module (43) configured to calculate a first shape parameter relating to the ratio of the area of ​​the flat bottom surface to the area of ​​the entire flat surface, The processing unit includes a center ratio module (46) configured to determine the length of the shortest side of the minimum circumscribing rectangle (22) of the entire flat surface and to calculate a second shape parameter relating to the ratio between the distance between two centers determined by the centering module and the length of the shortest side, The aforementioned classification module is The first shape parameter, which corresponds to the percentage value of the area of ​​the flat bottom surface relative to the total area of ​​the flat surface, is less than or equal to a first identification threshold. The second shape parameter, which corresponds to the ratio between the distance between the two centers determined by the alignment module and the length of the shortest side of the minimum circumscribing rectangle (22) of the entire flat surface, is less than or equal to the second identification threshold. The system according to claim 15, wherein a detected object is classified as unstable if one or more of the following conditions are met: a third axial direction parameter and a fourth axial direction parameter, which correspond to the ratio of the lengths of the axes of the minimum circumscribing rectangle (21) of the flat bottom surface having the length of the axis angularly closest to the minimum circumscribing rectangle of the entire flat surface, are less than or equal to a third identification threshold and a fourth identification threshold, respectively.

18. The processing unit (4) is configured to acquire several shape parameters starting from at least the flat bottom surface, The processing unit (4) includes a classification module (400) configured to determine whether a detected object is stable or unstable based on whether one or more of the shape parameters are greater than or less than a relative predetermined identification threshold. The processing unit (4) includes a ratio module (43) configured to calculate a first shape parameter relating to the ratio of the area of ​​the flat bottom surface to the area of ​​the entire flat surface, The processing unit includes a center ratio module (46) configured to determine the length of the shortest side of the minimum circumscribing rectangle (22) of the entire flat surface and to calculate a second shape parameter relating to the ratio between the distance between two centers determined by the centering module and the length of the shortest side, The aforementioned classification module is The first shape parameter, which corresponds to the percentage value of the area of ​​the flat bottom surface relative to the total area of ​​the flat surface, is less than or equal to a first identification threshold. The second shape parameter, which corresponds to the ratio between the distance between the two centers determined by the alignment module and the length of the shortest side of the minimum circumscribing rectangle (22) of the entire flat surface, is less than or equal to the second identification threshold. The system is configured to classify an object as unstable if one or more of the following conditions are met: a third axial direction parameter and a fourth axial direction parameter, which correspond to the ratio of the lengths of the axes of the minimum circumscribing rectangle (21) of the flat bottom surface having the axis length that is angularly closest to the minimum circumscribing rectangle of the entire flat surface, are less than or equal to a third identification threshold and a fourth identification threshold, respectively; The system according to claim 16, wherein the classification module is configured to classify a detected object as unstable if a fifth shape parameter, which corresponds to the ratio of the total height of the detected object to the shortest side of the minimum circumscribing rectangle (21) of the flat bottom surface, is greater than or equal to a fifth identification threshold.

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