Patent Abstract:
The problem of singulating products that are provided in a pallet layer is solved by breaking up the pallet layer so that each product can be handled separately by a robot tool and outputted in at least one line according to a predetermined orientation. The singulator includes a layer drop zone that receives a pallet layer of products, a break-up system that separates the products by creating gaps therebetween, yielding separated products, a vision system that determines characteristics and position of each separated product; and a robot equipped with a tool that receives information indicative of the characteristics and position of said each separated product to grip and position each separated product onto an output station within at least one line.

Full Description:
This application claims the benefit of U.S. Provisional Application No. 61/811,343, filed on Apr. 12, 2013, the contents of which are incorporated by reference herein. 
    
    
     FIELD 
     The present disclosure relates to depalletizing and to product conveying. More specifically, the present disclosure relates to singulation systems. 
     BACKGROUND 
     Singulation systems, also known as singulators, are known in the art of product conveying and depalletizing as systems for taking a group of products, such as a pallet layer of boxes, picking up each product, one at a time, and positioning the products one after the other. 
     U.S. Pat. No. 6,471,044 B1, issued on Oct. 29, 2002 to Isaacs et al. and being titled “Hold and Release Singulator” describes a singulator that includes a hold-and-release singulator module sandwiched between an infeed belt conveyor and an exit belt conveyor. The hold-and-release singulator module includes parallel independently-driven and paced conveyor belts that allows outputting parcels one at a time at the output end of the module. An optional vision system can be provided to take and process an image of the parcels to determine the two-dimensional location of the perimeter of each parcel. 
     A first drawback of the singulator from Isaacs et al. is that the parcels are fed pre-separated to the system and, as such, the system is not suitable to singulate a pallet layer, wherein products are closely packed. 
     Another drawback of the singulator from Isaacs is that there is no simple means to orient the outputted parcels. 
     Singulators are also well-known in the field of mail sorting. An example of a mail singulator is described in U.S. Pat. No. 4,634,328, issued to Carrell on Jan. 6, 1987 and titled “Mail Singulation System”. While the singulator proposed by Carrell is configured to receive unsingulated mail in bulk, the tool and vision system used are limited to handling lightweight objects. Also, the robot tool being in the form of a pusher, orienting the mail object is again limited. 
     The singulator from Carrell allows highlights the fact that any efficient singulator system is configured for receiving specific objects in a predetermined configuration and to output the same objects, singulated and within an orientation determined by the singulator. 
     A singulator adapted to receive a pallet layer at its input and to provide at the output singulated and oriented objects from the pallet layer is thus desirable. 
     SUMMARY 
     The problem of singulating products that are provided in a pallet layer is hereby solved by breaking up the pallet layer so that each product can be handled separately by a robot tool and outputted in at least one line according to a predetermined orientation. 
     According to an illustrative embodiment, there is provided a singulator for receiving a pallet layer of products as input, the singulator comprising: 
     a layer break-up system to receive the pallet layer and for separating the products thereof, yielding separated products; 
     a vision system that determines at least one characteristic and a position of each separated product; and 
     at least one robot equipped with a tool that receives information indicative of the at least one characteristic and the position of said each separated product to grip and position said each separated product onto an output station within at least one line. 
     According to another illustrative embodiment, there is provided a method for singulating products from a pallet layer, the method comprising: 
     breaking up the pallet layer, yielding separated products; 
     determining at least one characteristic and a position of each of the separated products; and 
     for each of the separated products, using the at least one characteristic and the position thereof to grip and then position said each separated product within at least one output line. 
     According to still another embodiment, there is provided a singulator comprising a break-up station that receives and separates a pallet layer of products, yielding separated products, and a robot that uses an orientation and a position of the separated products to grip and position onto an output station in at least one line each of the separated products. 
     Other objects, advantages and features of the singulator and singulating method will become more apparent upon reading the following non restrictive description of preferred embodiments thereof, given by way of example only with reference to the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the appended drawings: 
         FIG. 1  is a perspective view of a first illustrative embodiment of a singulator; 
         FIG. 2  is a top plan view of the singulator from  FIG. 1 ; and 
         FIG. 3  is a top plan schematic view illustrating an illustrative embodiment of a method for singulating products from a pallet layer. 
     
    
    
     DETAILED DESCRIPTION 
     In the following description, similar features in the drawings have been given similar reference numerals, and in order not to weigh down the figures, some elements are not referred to in some figures if they were already identified in a precedent figure. 
     The use of the word “a” or “an” when used in conjunction with the term “comprising” in the claims and/or the specification may mean “one”, but it is also consistent with the meaning of “one or more”, “at least one”, and “one or more than one”. Similarly, the word “another” may mean at least a second or more. 
     As used in this specification and claim(s), the words “comprising” (and any form of comprising, such as “comprise” and “comprises”), “having” (and any form of having, such as “have” and “has”), “including” (and any form of including, such as “include” and “includes”) or “containing” (and any form of containing, such as “contain” and “contains”), are inclusive or open-ended and do not exclude additional, unrecited elements. 
     The expression “robot” should be construed in the description and in the claims in a broad way, so as to include any device, system, apparatus or arrangement of parts that can automatically or semi-automatically operate a task onto another system, object, body or else. 
     A robotized singulator  10  according to a first illustrative embodiment will now be described with reference to  FIGS. 1 and 2 . 
     The singulator  10  comprises a layer drop zone  12  that receives a layer  14  of products  16 - 18 , a layer break-up system  19  positioned downstream from the layer drop zone  12 , a vision system, including two arrays of sensors  20  that locates and characterizes each of the products  16 - 18 , two robots  22 , each equipped with an end of arm tool  24 , and two output stations in the form of output and reject conveyors  25  and  26 , both positioned downstream from the layer break-up system  19 . 
     The layer drop zone  12  is in the form of a motorized conveyor that is configured to receive a full pallet layer  14  of products  16 - 18  thereon and to transfer the pallet layer  14  to the layer drop zone  12 . 
     The conveyor  12  can be of the roller type, of the belt type or can take any form that includes a surface  28  wide enough to receive a full pallet layer of typical size and that is motorized to transfer the full pallet layer  14  to the layer break-up zone  19 . 
     The expressions “layer” and “pallet layer” should be construed in the description and in the claims as to include a homogeneous or inhomogeneous group of products depalettized together from an input pallet  14 . Typically, there are no gaps between the products  16  and  18  in the input layer  14 . A typical layer size (width×length) is 101.6 cm×121.9 cm (40″×48″). The singulator  10  and more specifically the layer drop zone  12  is however not limited to receive a layer of that size and can be adapted to receive other or variable layer sizes, for example between 81.3 cm×101.6 cm (32″×40″) and 111.8 cm×132.1 (44″×52″). 
     According to another embodiment, the conveyor  12  is not motorized and a further mechanism is used to move the layer  14  onto the conveyor  12 . According to still another embodiment, the layer drop zone  12  is omitted and the layer beak up system  19  is further configured to receive the full pallet layer  14 . 
     According to the first illustrative embodiment, the layer  14  is deposited in the layer drop zone  12  by an external system, such as a fork lift (not shown), a depalletizing robot  30  or another conveyor (not shown). 
     Since motorized conveyors, fork lift and depalletizing robots are believed to be well known in the art, they will not be described herein in more detail for concision purposes. 
     The expression “product” should be construed broadly in the description and in the claims as including any type of consumer goods in any type of packaging, such as without limitations closed cartons, tote, open top carton, shrink wrapped with or without tray, and non-shrink wrapped tray. Also, product dimensions may vary greatly between each different type of product. Typical dimensions of the products (width×length×height) can be between 10.2 cm×15.2 cm×5.1 cm (4″×6″×2″) and 63.5×63.5×61 (25″×25″×24″). 
     Two numeral references  16  and  18  are used in the description to emphasis that there can be different products in a single pallet layer  14 , having same or different geometry. All products can also be identical. 
     The layer break-up system  19  is provided to create gaps  33  and  35  between each products  16  and  18  that are sufficient to allow the vision system  20  to detect each product independently. According to the first illustrative embodiment, the layer break-up system  19  yields gaps  33  and  25  typically between 2.5 cm (1″) and 5 cm (2″) between two adjacent products  16 - 18 , yielding separated products  16 - 18 . 
     The layer break-up system  19  is in the form of a multi-belt conveyor that includes a plurality of diverging motorized belts  32  that defines together a tapered conveying surface  34 . 
     The belts  32  are independently driven so as to allow their running at different speeds so that, in operation, lateral and longitudinal gaps  34  and  35  are created and increased from the input side edge  36  of the conveyor  19  to the output side edge  38  thereof. 
     It is believed to be within the reach of a person skilled in the art of product conveying to dimension and operate the multi-belt conveyor  19  to yield gaps  33  and  35  between products  16  and  18  that are sufficient to be located and characterized by the vision system  20  and picked up by one of the tools  24 . 
     The break-up system  19  is not limited to the embodiment illustrated in  FIGS. 1 and 2 . According to another embodiment (not shown), the break-up system includes one or a combination of independently driven skewed rollers, a multi-belt conveyor and other multi-speed conveying mechanism. 
     Since multi-belt and multi-speed conveyors are believed to be well known in the art, they will not be described herein in more detail for concision purposes. 
     The two arrays of sensors  20  (two shown in  FIG. 1 ) are secured to the ceiling (not shown) above the output end of the layer break-up system  19  and is positioned and configured to acquire an image of the layer located in the break-up system  19 . According to the first illustrated embodiment, each array  20  includes 3 sensors. 
     Examples of suitable sensors include typical industrial cameras or the Kinect Device™ from Microsoft™. According to another embodiment, the sensors are in the form of two-dimensional color cameras. According to still another embodiment, the vision sensor includes one or more lasers and one or more two-dimensional cameras that yield a triangulation setup that allows three-dimensional reconstructions of the scene as the conveyor moves. 
     According to the first illustrated embodiment, the image acquired by the vision system is a depth map allowing three-dimensional view of the layer within the layer break-up system  19 . According to another embodiment, the image is two-dimensional. The image can be monochrome or in colors. 
     The vision system includes a computer (not shown) that is programmed for analyzing the sensor data, to detect and validate product characteristics, locate each product  16  and  18  and calculate product coordinates an orientation in a reference system that is known to the robots  22 . 
     Examples of product characteristics detected and/or validated by the vision system includes without restrictions the dimension and shape of the product  16  or  18 , separation between adjacent products, optimal exit vector for the product  16  or  18 , colors, writings, logos, signs and other printings, engravings, etc. thereon that can be seen from a top and/or perspective view of the product. 
     The validation of the product  16  or  18  may include comparing the 3D model thereof to a model of the product as it should look like so as to detect any defect thereon. Predetermined criteria stored for example on the computer or accessible therefrom can be used to trigger the detection of a damaged product. 
     According to another embodiment (not shown), the array of sensors  20  includes more or less than three sensors. The number of array may also be different than two (2). Also, the array of sensors  20  may also be secured to a wall adjacent the break-up system  19  or to a frame element or gantry (both not shown) that positions the array of sensors  20  so as to yield a field of view that includes the break-up system  19  or at least a portion thereof. 
     According to a more specific embodiment, the vision system is configured to see the conveyor surface  34  through the gaps between the products. According to this specific embodiment, the light reflecting properties of the conveyor are determined in advanced. Considering that products  16 - 18  come in a large variety and that some of these products  16 - 18  may have reflecting properties that are not well suited for the vision sensors selected  20 , recognizing the conveyor surface  34  through the gaps between the products  16 - 18  allows in such occurrences to better the identification and/or characterization of the products  16 - 18  by the vision system. 
     Since vision systems and vision sensors are believed to be well known in the art, they will not be described herein in more detail for concision purposes. 
     The robots  22  are in the form of conventional industrial robots, each equipped with an end of arm tool  24  adapted for handling all products  16 - 18  targeted by the singulator  10 . The robots  22  used information indicative of the characteristics and position of each separated product  16 - 18  to grip and position each so separated product  16  or  18  onto a selected one of the output and reject conveyors  25  and  26 . For examples, information related to a product  16  or  18  that has been found to be damaged by the vision system is sent to the robot  22  which is nearer the reject conveyor  26 . This robot  22  can then pick up the damaged product and move it from the break-up system  19  to the damaged conveyor  26 . 
     The gaps  33  and  35  created between the products  16 - 18  by the break-up system  19  allow anyone of the two robots  22  to grab the products  16 - 18  with their end of arm tool  24 . 
     According to the first illustrated embodiment, the end of arm tool  24  includes adjustable vertical side plates  40  together that define a clamp. The plates  40  are movable towards and away one another. 
     According to another embodiment (not shown), the end of arm tool is a vacuum gripper. Since clamp-type and vacuum-type grippers are believed to be well known in the art, they will not be described herein in more detail for concision purposes. 
     In operation of the robots  22 , one of the two robots is sent the information indicative of the characteristics and position of a product  16  or  18  selected to be picked up from the break-up system  19 . The tool  24  opens sufficiently to be positioned over the selected product and so as to have its side plates positioned on respective opposite sides thereof. The plates  40  are then moved until they contact the selected product  16  or  18  and the robot  22  moved the tool  24  with the selected product on the corresponding one of the output and reject conveyors  25  or  26 . 
     It is to be noted that a force is applied by the tool  24  between the two plates  40  which is sufficient to hold the product while it is raised but not too strong as to damaged or deformed the selected product. The required force is determined by the robot controller (not shown) using the information indicative of the selected product characteristics. 
     While the first illustrative embodiment includes two (2) robots, a singulator according to another embodiment may include one or more than two (2) robots depending on the application, desired cadency and/or product-type. 
     The output of the singulator  10  is a flow products  16 - 18  positioned on the output conveyor  25  in a desired orientation or in groups according to specific patterns. Examples of such patterns include groups of products  16 - 18  that are assembled according to a pre-defined arrangement, including specific orientations. Such arranged products are said to be singulated. A typical group size is between one (1) and five (5) products  16 - 18 . 
     The expression “singulated” is not intended to be construed herein in any way and should be construed to include any product that has been separated from a pallet layer and moved individually to a selected area. 
     According to the first illustrated embodiment, products  16 - 18  that are determined by the vision system to be damaged or more generally that do not have predetermined characteristics are picked up and moved to the reject conveyor  26  by the nearest robot  22 . 
     According to another embodiment (not shown), both robots  22  are operated so as to move undamaged and damaged products from the break-up system  19  to the corresponding conveyor  25  or  26  respectively. 
     According to still another embodiment (not shown), the products  16 - 18  are selected to be dropped on either one of the two conveyors  25 - 26  based on other criteria than being damaged or undamaged. 
     According to a further embodiment, the second output conveyor  26  is omitted and all products  16 - 18  are positioned onto a same output conveyor  25 . 
     The output and reject conveyors  25  and  26  are in the form of linear conveyors adapted for receiving singulated products. Anyone or both of the conveyors  25 - 26  can be of the roller type or of the belt type and can be motorized or not. 
     A method for singulating products  16 - 18  from a pallet layer  14  will now be described with reference to  FIG. 3 . 
     A complete layer  14  of product  16 - 18  is first provided, for example on the layer drop zone  12 , by an external system such as for example a layer handling robot (step  1 ). The layer  14  may be dropped slightly skewed to facilitate product separation later in the process. 
     In step  2 , the layer  14  is then transferred from the drop zone  12  to a layer break-up zone or system  19  (see arrow  42 ). 
     In step  3 , the layer  14  is broke-up, resulting in the products  16  and  18  from the layer  14  being separated or distanced from one another (see arrow  44 ). 
     More specifically, the break-up zone  19  creates gaps  33  and  35  between each product as the layer  14  is transferred (step  3 ). The gaps  33  and  35  created are such as to allow a vision system to locate each product  16 - 18  without ambiguity and for a tool  24  to pick up each product individually. 
     Using a vision system, each product  16 - 18  are located using coordinates in a reference system that is known to the robot(s) (step  4 ). The vision system also detects product characteristics and identifies products that are invalid and should be rejected. 
     The robots  22  uses the coordinates obtained from the vision system to grip the products and slide them on the conveyor surface to realign and reposition them in the correct position and orientation on the output conveyor  25  (step  5 ). Products that have been declared invalid are sent to the reject conveyor  26  instead. 
     The output conveyor  25  feeds a file of singulated products, or groups of products, to an external system (step  6 ) (see arrow  46 ). 
     It is to be noted that modifications could be made to the singulator and singulating method described hereinabove and illustrated in the appended drawings. For example:
         in order to facilitate layer break-up, the input layer  14  can be deposited on the layer drop zone  12  in a certain orientation. Communication with the external equipment handling the layer  14  may be necessary to request the appropriate drop angle;   the layer break-up system  19  can be a combination of conveyors running at various speeds and/or independently driven skewed roller sections or belts. Typically, gaps of 2.5 cm (1″) to 5 cm (2″) in both the X-axis (direction of travel) and the Y-axis (perpendicular to the direction of travel) are created by the system  19 . According to another embodiment (not shown), the layer break-up system  19  creates a gap between the products  16 - 18  only along the X or Y axis. The vision system and robot tool  24  are configured accordingly;   the sensors  20  of the vision system are positioned vertically above the layer break-up zone. Additional sensors may be placed at an angle to provide a different perspective. The total number of sensors is adapted to the final configuration;   the vision system can be further configured or programmed as an inspection system to further monitor and/or validate product characteristics;   the number of robots  22  and their position on the layout are adapted to the application. The robots  22  can be standard 4-axis industrial robots. A 6-axis robot or a gantry type robot can also be used;   the singulator  10  can include one or more output conveyors that are positioned and configured so as to have a direction of travel and speed that are not necessarily the same as that of the drop and break-up zone conveyors  12  and  19 ;   the input of the singulator can be in the form of products deposited manually in any position and orientation on the drop zone;   the singulator can include a slip sheet removal system (not shown) to remove a slip sheet on the layer  14  when such a sheet is present. Since slip sheet removal systems are believed to be well-known in the art, they will not be described herein in more detail for concision purposes; and   the robots  22  can be operated so as to yield an output of the singulator  10  as being groups of products stacked over each other instead of being side by side.       

     It is to be understood that embodiments of the singulator and singulating method are not limited in their application to the details of construction and parts illustrated in the accompanying drawings and described hereinabove. Other embodiments can be foreseen and practiced in various ways. It is also to be understood that the phraseology or terminology used herein is for the purpose of description and not limitation. Hence, although the singulator and singulating method have been described hereinabove by way of illustrative embodiments thereof, it can be modified, without departing from the spirit, scope and nature of the subject invention.

Technology Classification (CPC): 1