SE541843C2

SE541843C2 - Systems and methods of gripping and emptying a bag

Info

Publication number: SE541843C2
Application number: SE1751638A
Authority: SE
Inventors: Christian Toräng; Stefan Holmertz; Stefan Nilsson; Tommy Peresin
Original assignee: Envac Optibag Ab
Priority date: 2017-12-22
Filing date: 2017-12-22
Publication date: 2019-12-27
Also published as: SE1751638A1

Description

SYSTEMS AND METHODS OF GRIPPING AND EMPTYING A BAG Technical field The present disclosure relates to a system and a method of gripping and emptying bags, in particular waste bags and more particularly disposable waste bags.

Background It is known and generally desirable, to sort waste into different fractions for recycling. Economic and environmental handling of the waste requires some types of waste to be packed and thereafter transported to a sorting plant for further sorting and/or processing, e.g. recycling. An environmental way is to sort the waste at waste sources and to pack waste into different categories, such as recyclable plastic, metal, glass, etc.

Disposable waste bags are widely used for containing and transporting waste. Such a waste bag is normally made of thin, flexible, plastic film, nonwoven fabric, or plastic textile, e.g. by blow moulding. Alternatively, the waste bags may be heat sealed together or bonded by adhesions, welding or stitching.

The waste bags filled with wastes are transported to the sorting plant for sorting. Systems and methods for sorting of waste are known from, e.g. W02004/050264A1. Waste bags with identifications, such as different colours, can be used for sorting the waste bags containing different sorts of waste.

However, in areas with limited access of waste carrier vehicles, bins, such as villages accessible only by stair paths and the places in a center of a pedestrian area, the waste bags are normally collected in a larger bag. The larger bag is carried to waste carrier vehicles by a person and then transported to the sorting plant. Thus, the waste bags contained inside the larger bag need to be removed from the larger bag to be able to be sorted. US5002451 A discloses a waste material debagging apparatus for emptying waste bags.

However, a drawback of such debagging apparatus is that when the larger bag is debagged by a destructive debagging process, e.g., by a penetrating means, the waste bags contained in the larger bag are normally broken such that the waste already sorted at waste sources will be mixed up again. Thus, the different categories of waste have to be sorted once again in the sorting plant. Furthermore, due to the scattered waste, the debagging devices and the sorting plant have to be cleaned more frequently.

The debagging process can be manually handled to secure the integrity of the contained waste bags. However, such a manual process is tedious and inefficient.

While waste bags, systems and methods of debagging waste bags mentioned above have found extensive use, there is a desire to provide a disposable waste bag which facilitates the debagging and thus improves the debagging efficiency.

Therefore, there remains a need for an improved disposable waste bag.

Summary An object of the present disclosure is to provide improved systems and methods for handling and emptying bags, and in particular disposable waste bags.

A particular object is to provide systems and methods which are improved in terms of facilitating and improving debagging of smaller waste bags from a bigger waste bag, such that the smaller waste bags can be sorted.

The invention is defined by the appended independent claims, with embodiments being set forth in the appended dependent claims in the following description and in the attached drawings.

According to a first aspect, there is provided a system for recycling waste, comprising a plurality of bags, each comprising an open end portion, a closed end portion, spaced from the open end portion, as seen in a longitudinal direction of the bag, a wall, extending between the closed end portion and the open end portion, and an optically readable element arranged on the wall of the bag, which optically readable element represents information of a relative position of at least the closed end portion, and a bag gripping system comprising an optical device, for capturing 3D data of the bag and for capturing an image of a wall of the bag, said image depicting an optically readable element, which represents information of a relative position of at least a closed end portion of the bag, a control device, comprising a processor arranged to perform the following steps using the captured 3D data and the captured image to determine a spatial position and orientation of the closed end portion of the bag, and controlling a vacuum gripping device to engage the closed end portion of the bag, such that the bag is held by the vacuum gripping device to an extent sufficient to allow the vacuum gripping device to lift or move the bag. The optical device is configured to capture an image of the optically readable element. The optical device is configured to capture 3D data of the one of said bags, the bag being filled with contents to at least 10 % of its volume, preferably at least 25 % or at least 50 %. The processor is configured to identify a position and orientation of the closed end portion, and to control the vacuum gripping device to engage the closed end portion.

The processor may be configured to control the gripping device so as to raise the closed end portion to an extent sufficient to cause evacuation of the contents from the bag.

The system may further comprise a conveyor for transporting the bag on a conveyor, wherein the optical device is configured to capture the image and the 3D data while the bag carried on the conveyor.

The system may further comprise transporting the bag on a conveyor, wherein the processor is configured to control the vacuum gripping device to engage the closed end portion while the bag is carried on the conveyor.

The vacuum gripping device may comprise a pressure sensor, arranged to measure a pressure inside a suction chamber of the vacuum gripping device and to provide pressure data to the control device, and the control device may be configured to determine whether a sufficient engagement with the bag has been achieved based on said pressure data. Based on such determination, it is possible to control a vacuum source to e.g. increase the vacuum level. Alternatively, it can be determined that a sufficient grip has not been achieved, and that a new attempt to grip the bag may be necessary, or that the vacuum gripping device may need cleaning.

According to a second aspect, there is provided a method of gripping a bag, comprising: providing a disposable waste bag comprising an open end portion, a closed end portion, spaced from the open end portion, as seen in a longitudinal direction of the bag, a wall, extending between the closed end portion and the open end portion, and an optically readable element (3) arranged on the wall of the bag, which optically readable element represents information of a relative position of at least the closed end portion, the bag being filled with contents to at least 10 % of its volume, preferably at least 25 % or at least 50 %, arranging the bag on a conveyor, capturing an image of at least the wall of the bag, said image depicting an optically readable element, which represents information of a relative position of at least the closed end portion, capturing 3D data of the bag, using the image including the optically readable element and the 3D data to determine a spatial position and orientation of the closed end portion, and controlling a vacuum gripping device to engage the closed end portion.

In the method, capturing 3D data may comprise laser scanning, e.g. by a line laser.

In the method, capturing the image may comprise scanning, e.g. by one or a plurality of cameras.

The captured 3D data may comprise stereo images.

The method may further comprise moving the bag by means of a conveyor after the vacuum gripping device engaging the closed end portion.

The vacuum gripping device may be controlled to lift the closed end portion upwardly.

The contents may comprise a plurality of individual bags having a smaller volume than the bag, and wherein the smaller bags are evacuated from the bag and transported to a sorting station, where the bags are sorted into at least two fractions depending on a parameter that is derivable from said bags.

According to a third aspect, there is provided a method of emptying a bag, comprising providing a disposable waste bag comprising an open end portion, a closed end portion, spaced from the open end portion, as seen in a longitudinal direction of the bag, a wall, extending between the closed end portion and the open end portion, and an optically readable element arranged on the wall of the bag, which optically readable element represents information of a relative position of at least the closed end portion, the bag being filled with contents to at least 10 % of its volume, preferably at least 25 % or at least 50 %, arranging the bag on the conveyor, capturing an image of at least a first portion of the bag, said image depicting the optically readable element, capturing 3D data of the bag, using the image and the 3D data to determine a spatial position and orientation of the closed end portion of the bag, controlling a vacuum gripping device to engage the closed end portion, and moving the closed end portion relative to the contents such that the contents are evacuated from the bag.

The method may further comprise moving the bag by means of a conveyor after the gripping device engaging the closed end portion.

In the method, the vacuum gripping device may be controlled to lift the closed end portion upwardly.

The contents may comprise a plurality of individual waste bags having a smaller volume than the bag, and wherein the smaller waste bags are evacuated from the bag and transported to a sorting station, where the smaller bags are sorted into at least two fractions depending on a parameter that is derivable from said bags.

The method may further comprise measuring a pressure inside a suction chamber of the vacuum gripping device, and to determine whether a sufficient engagement with the bag has been achieved based on pressure data provided through said measuring.

In the following, and “optically readable element” is defined as one or more patterns that is/are specifically adapted for machine reading.

The optically readable element may comprise at least one point representing information of a relative position of the at least a closed end portion of the bag.

The point may be identified as an intersection between at least two lines, which meet at an angle of 15°-165°, 30°-150°, preferably 45°-135° or 80°-100°.

Lines may be created by line elements, or by edges of geometric shapes, such as rectangles, triangles, etc. That is, the lines may be merely lines formed of a line with different color than its background. Alternatively, the lines may be formed by the edge of the geometric shape having a different color than the background.

The point may comprise a unique identifier associated to it such that the point is uniquely identifiable.

The optically readable element may comprise a plurality of said uniquely identifiable points, disposed over an area of the optically readable element.

The optically readable element may be arranged within a portion of the bag that is situated within a distance of less than 50 % of a length of the bag, from the closed end.

The optically readable element may extend over at least 10%, preferably at least 20 %, 30 %, 40 % or 50 %, of the length of the bag, in the longitudinal direction of the bag.

The optically readable element may extend over at least 50 %, preferably at least 60 % or 70 %, of a circumference of the bag along a circumferential direction of the bag.

The information may be represented by a sub area of the optically readable element which is at most 50 %, preferably at most 40 %, more preferably at most 30 %, 20 % or 10 % of the area of the optically readable element.

The optically readable element may comprise a pattern, color or colors, or a symbol.

For example, the optically readable element may comprise a one or more patterns and/or symbols. Such patterns and/or symbols may be monochrome or they may comprise two or more colors.

The pattern may comprise a geometrical pattern. The optically readable element may comprise a character or a number. The optically readable element may comprise a plurality of stripes. At least two stripes may have different widths.

The closed end portion of the bag may be formed by a weld across the bag along the transverse direction of the bag. In this case the bag may be formed by a tubular member, having a cross weld to form the closed end.

Alternatively, the closed end may be formed by a constriction of a portion of the bag. In this case the bag may be formed by a tubular member, which is constricted to form the closed end.

The constriction may be maintained by at least one of a knot, a cord, a cable tie or a clamp.

The bag may be formed of a flexible material, such as a polymer material or paper. The material may be a thin sheet or film, provided as one or more sheets which are joined together, or as a tube, which is processed by welding the portions that are to form gripping and corner portions.

Preferably, the bag is formed of paper, polymer film, woven fibre web or non-woven fibre web. As one option, a coated paper may be used.

A volume of the bag may be at least 5 litres, preferably at least 10 litres, more preferably at least 20 litres, 30 litres, 40 litres or 50 litres.

The volume of the bag may be at most 350 litres, preferably at most 300 litres, more preferably at most 250 litres, 200 litres, 150 litres or 100 litres.

According to a fourth aspect, there is provided a method of processing a bag, comprising providing a disposable waste bag comprising an open end portion, a closed end portion, spaced from the open end portion, as seen in a longitudinal direction of the bag, a wall, extending between the closed end portion and the open end portion, and an optically readable element arranged on the wall of the bag, which optically readable element represents information of a relative position of at least the closed end portion. In the method, the bag is filled with contents to at least 10 % of its volume, preferably at least 25 % or at least 50 %. The method comprises transporting the bag on a first conveyor section, capturing a first image of at least a first portion of the bag, said first image depicting the optically readable element, capturing 3D data of the bag, using the first image and the 3D data to determine a spatial position and orientation of the closed end portion of the bag, controlling a first vacuum gripping device to engage the bag, lifting the bag to a second conveyor section, transporting the bag on the second conveyor section, capturing a second image of at least the first portion of the bag, said second image depicting the optically readable element, capturing 3D data of the bag, using the second image and the 3D data to determine a spatial position and orientation of the closed end portion of the bag, controlling a second vacuum gripping device to engage the closed end portion, and moving the closed end portion relative to the contents such that the contents are evacuated from the bag.

The first and second conveyor sections may be movable independently of each other.

The first and second conveyor sections may be separated by a gap. The method may further comprise transferring a non-identifiable item from the first conveyor section to a third conveyor section. Such third conveyor section may also be movable independently of the first and second conveyor sections.

The non-identifiable item may be transferred by gravity.

According to a fifth aspect, there is provided a system for processing waste, comprising a plurality of bags, each comprising an open end portion, a closed end portion, spaced from the open end portion, as seen in a longitudinal direction of the bag, a wall, extending between the closed end portion and the open end portion, and an optically readable element arranged on the wall of the bag, which optically readable element represents information of a relative position of at least the closed end portion. Each bag is filled with contents to at least 10 % of its volume, preferably at least 25 % or at least 50 %. The system further comprises a first conveyor section, adapted for transporting the bags, a second conveyor section, adapted for transporting the bags, a first gripping system comprising a first optical device, for capturing 3D data of the bag and for capturing an image of a wall of the bag, said image depicting an optically readable element, which represents information of a relative position of at least a closed end portion of the bag, a first control device, comprising a first processor arranged to perform the following steps: using the captured 3D data and the captured image to determine a spatial position and orientation of the closed end portion of the bag, and controlling a first vacuum gripping device to engage the bag on the first conveyor section, such that the bag is held by the vacuum gripping device to an extent sufficient to allow the vacuum gripping device to lift the bag onto the second conveyor section. The system further comprises a second gripping system comprising a second optical device, for capturing 3D data of the bag and for capturing an image of a wall of the bag, said image depicting an optically readable element, which represents information of a relative position of at least a closed end portion of the bag, a second control device, comprising a second processor arranged to perform the following steps: using the captured 3D data and the captured image to determine a spatial position and orientation of the closed end portion of the bag, and controlling a second vacuum gripping device to engage the closed end portion of the bag, such that the bag is held by the vacuum gripping device to an extent sufficient to allow the vacuum gripping device to lift or move the bag.

The first and second conveyor sections may be separated by a gap. The system may further comprise a third conveyor section, which is situated below said gap, such that items falling into said gap are received by the third conveyor section.

Brief description of the drawings Fig. 1 schematically illustrates a disposable waste bag in a collapsed state.

Fig. 2 schematically illustrates an example of the bag of Fig. 1.

Fig. 3 schematically illustrates another example of the bag of Fig. 1. Figs 4a-4b schematically illustrates a device for emptying waste bags. Fig. 5 schematically illustrates another embodiment of a disposable waste bag.

Figs 6a-6b schematically illustrate a bag emptying process.

Figs 7a-7b schematically illustrate a robot having a vacuum gripping device.

Figs 8a-8b schematically illustrate a bag emptying system having a vacuum gripping device.

Detailed description Fig. 1 schematically illustrates a disposable waste bag 100 in a collapsed state. The disposable waste bag comprises an open end 2, a closed end 1, spaced from the open end 2, in a longitudinal direction of the bag 100.

An optically readable element 3 is arranged on the wall of the bag between the closed end 1 and the open end 2. The optically readable element 3 represents information of a relative position of at least the closed end portion of the bag. The information may comprise, e.g., an orientation of the portion, a distance from the pattern to the portion.

It is possible to provide the optically readable element with additional information, as would be the case with a barcode, a QR code, or the like. In addition, it is possible to supplement the optically readable element with another type of information carrier, such as an RFID element, or the like. Figs 1-3 illustrate three disposable waste bags with different optically readable elements 3. The optically readable element may comprise individual sub elements 7, as shown in Figs 1-2. The sub elements 7 may be aligned, as in Figs 1-2 or stochastic arranged in the area. At least one sub element 7 may present information of a relative position of the closed end portion.

Alternatively, the optically readable element may comprise a plurality of stripes, as in Fig. 3. At least two stripes may have different widths.

The optically readable element may comprise a geometrical pattern, as shown in Fig.2. The optically readable element may comprise a character, as shown in Fig.1. Alternatively, the optically readable element may comprise a number.

The optically readable element may comprise at least one point 8 identified as an intersection between at least two lines, as shown in Figs 1-2.

The point 8 may represent information of a relative position of at least the closed end portion of the bag.

The optically readable element may comprise a plurality of such points 8, disposed over an area of the optically readable element 3, as in Figs 1-2.

The optically readable element may be arranged closed to the closed end 1, as shown in Figs 1-3. A distance from the closed end to the optically readable element may be less than 50 % of a length of the bag.

The optically readable element may extend in the longitudinal direction, over at least 10%, of the length of the bag.

The disposable waste bags shown in Figs 1-3 are in a collapsed state showing a front side provided with the optically readable element. The back side of the bag (not shown) may be provided with an optically readable element. The optically readable element may be extended over at least 50 %, preferably at least 60 % or 70 %, of a circumference of the bag along a circumferential direction of the bag.

By extending the optically readable element in the longitudinal direction and/or the circumferential direction of the bag, the likelihood that at least a sufficient part of the optically readable element is visible, when the bag is filled with waste, and transported on a conveyor, in which case the bag may be standing up, or lying on its side.

In Figs 1-3, a weld for closing the closed end portion may be linear. As one option, the weld may comprise at least one non-linear portion. As another option, the weld may be curved. Typically, the weld may extend across the entire width of the bag.

Fig. 4a schematically illustrates a waste bag emptying system, comprising a conveyor 205 for transporting a plurality of waste bags 100, a support frame 201 and a robot 203.

A pair of cameras 202a, 202b may be arranged on the support frame. Further camera(s) may be arranged e.g. on the robot 203, such as on or close to the gripping device. In particular a line laser scanner may be arranged either on the support frame 201 or on the robot 203, or on both.

The robot 203 is illustrated as being arranged on a floor beside the conveyor 205, but may alternatively be arranged on the support frame 201.

The robot 203 may be a general industrial type robot with 5 or 6 axes, fitted with a vacuum gripping device 204 that is suitable for engaging the wall surface of the waste bag 100.

As an alternative, the robot may be a portal type robot.

A controller 300 may be provided for controlling the robot and the conveyor 205. To this end, the controller 300 may receive input data from the camera(s) 202a, 202b.

As illustrated in Fig. 4a and 4b, waste bags 100 are transported on the conveyor 205. As a preceding step, the waste bags 100 may be prearranged on the conveyor 205, e.g. with their longitudinal direction along the transportation direction, as illustrated. Moreover, the waste bags 100 may be separated from each other along the transportation direction, the separation being sufficient to allow for the identification, gripping and emptying of the waste bags.

As a waste bag 100 reaches the emptying station, the conveyor 205 may, but need not, slow down or stop. Images of the waste bag 100 are captured by the cameras 202a, 202b, and any laser device (not shown).

Optically readable elements are identified and a spatial position and orientation of the closed end portion is determined.

The robot 203 with the gripping device 204 is then directed to engage the closed end portion 4. Once engaged, the robot 203 may typically lift the closed end portion 4 upwardly. During the lifting, the conveyor 205 may, but need not, move in the transportation direction.

Methods of determining the geometry of 3D objects and controlling a robot to engage such objects are known from e.g. W02007046763A1.

Once the closed end portion 4 has reached a predetermined vertical level, such that the contents of the waste bag 100 can be assumed to have been evacuated, the robot 203 may optionally shake or otherwise agitate the supposedly empty waste bag 100.

The robot 203 may then dispose of the empty waste bag, e.g. in a container (not shown) near the emptying station. The contents of the waste bag may continue to be transported on the conveyor for further processing, such as sorting.

Fig. 5 schematically illustrates a disposable waste bag having gusset creases 61 extending longitudinally and thus effectively forming, together with the closed end (e.g. a weld) corner indentions 51, which counteract material lingering at the corner portions of the closed end of the bag.

Figs 6a-6c schematically illustrate the various positions of the bag 100 and the smaller, individual waste bags 101.

In Fig. 6a, the bag 100 is in its upright position, with the closed end downwardly and the open end upwardly oriented, such as would be the case when the bag is held by a waste bag holder and when it is being carried from the waste bag holder to e.g. a collection vehicle. In the latter case, the open end would be temporarily closed, e.g. by the hand of the person carrying it. The smaller, individual waste bags 101 are drawn by gravity towards the closed end of the bag 100.

Fig. 6b schematically illustrates the bag 100 when it is being transported on the conveyor 205 (Fig. 4a). the bag 100 is then typically lying down with a portion of its wall facing downwardly and the individual waste bags drawn by gravity towards this downwardly facing wall portion.

Fig. 6c schematically illustrates the bag 100, when it is being held by the vacuum gripping device 204 and vertically separated from the conveyor 205, such that the individual waste bags 101 are evacuated.

Fig. 7a schematically discloses a robot 203 provided with a vacuum gripping device 204. The robot 203, and its control, is known as such, and thus requires no further description.

Referring to fig. 7b, the vacuum gripping device 204 may comprise one or more vacuum actuated suction cups, each having a seal 2041, a suction chamber 2042, optionally a filter or trap 2043 for preventing dust, debris or liquid from clogging the vacuum source connection 2044, and a vacuum source 2045.

The seal 2041 may be formed of any material suitable for interaction with the bags 100. As one example, the seal may be rigid, e.g. being formed of a metallic material or of an engineering plastic. As another example, the seal may be resiliently flexible, for example by being formed by a rubber elastic material.

The filter may be formed as a porous filter or as a trap with baffles, adapted to catch particles or liquid and prevent them from reaching the vacuum source connection 2044.

Optionally, the (or each) vacuum suction chamber 2042 may be provided with a pressure sensor 2046, which may be connected to the control device, such that pressure data can be supplied to the control device.

Based on such pressure data, it is possible for the control device to determine whether a sufficient engagement of a bag 100 has been achieved.

For example, if the seal 2041 does not close properly against the bag 100, e.g. due to debris being stuck in between or due to a misalignment between the bag and the vacuum gripping device, the pressure will not drop low enough for a sufficient vacuum grip to be achievable. This will be indicated by the pressure sensor. In such cases, appropriate actions may be taken, including but not limited to, releasing and repositioning the gripping device for a new attempt, releasing and cleaning the gripping device, etc. Manipulation of the bag may be conditioned on a certain pressure level being achievable. That is, the bag is only lifted once a sufficiently low pressure, indicating a proper engagement of the vacuum gripping device with the bag 100, has been detected by the control device.

Referring to Figs 8a-8b, there is illustrated an alternative layout of a bag emptying system, which comprises three conveyor sections 3051, 3052, 3053 and two robots 3031, 3032, which here are illustrated as industrial robots having a respective vacuum gripping device. Each of the robots 3031 and 3032 may be provided with a respective vision system for identifying the position and orientation of each bag, as described above.

Between the first and second conveyor sections 3051, 3052, there is a gap 3061. The first robot 3031 is capable of lifting bags across this gap 3061.

In the system illustrated in Figs 8a-8b, bags 100 arrive on the first conveyor section 3051. At this point, the bags may have been singled, such that they arrive one by one, and thus not stacked, and horizontally oriented. However, the bags 100 may extend in any direction in the horizontal plane.

On arrival to the first robot 3031, the bag is identified and its orientation is determined.

If the bag 100 is properly identified and its orientation can be determined, the first robot 3031 will pick it up such that it remains horizontal or with its closed end at a lower vertical level than its open end. The first robot 3031 will position the bag 100 with its longitudinal direction parallel with the longitudinal direction of the second conveyor section 3052 and with the closed end trailing the open end.

From the second conveyor section 3052, the second robot 3032 may, using its associated vision system, identify an arriving bag, determine its orientation and grip it using its vacuum gripping device. The second robot 3032 is configured to grip the bag 100 by the bottom, and to lift it, such that the bag is emptied. The bag may be emptied onto the second conveyor section 3052, after which the contents of the bag is transported by the second conveyor section 3052 towards a subsequent processing step, such as sorting of the contents.

If the bag 100 is not properly identified at the first robot 3031, its orientation cannot be determined, or it is broken, then the bag will be allowed to drop down through the gap 3061 onto the third conveyor section 3053.

Likewise, items, such as individual bags 101, which are not contained in larger bags 100 and which arrive at the first conveyor section 3051 will fall into the gap 3061 onto the third conveyor section 3053.

The third conveyor section 3053 may lead the bag 100 and/or its contents back to the beginning of the first conveyor section 3051 for a new attempt. Alternatively, the third conveyor section 3053 may lead the bag to a manual handling station. As yet another alternative, the third conveyor section may lead any articles falling onto it directly to an optical sorting station, for sorting based on e.g. bag color, some optically readable means or RFID, as non-limiting examples.

Items falling through the gap 3061 may, as illustrated, merge with items emptied from the bags 100 at the second robot 3032.

Claims

1. A system for recycling waste, comprising: a plurality of bags (100), each comprising an open end portion (2), a closed end portion (1), spaced from the open end portion, as seen in a longitudinal direction of the bag (100), a wall, extending between the closed end portion and the open end portion, and characterized by an optically readable element (3) arranged on the wall of the bag, which optically readable element represents information of a relative position of at least the closed end portion, a bag gripping system comprising: an optical device (202a, 202b), for capturing 3D data of the bag and for capturing an image of a wall of the bag, said image depicting the optically readable element, which represents information of a relative position of at least a closed end portion of the bag, a control device (300), comprising a processor arranged to perform the following steps: using the captured 3D data and the captured image to determine a spatial position and orientation of the closed end portion of the bag, and controlling a vacuum gripping device to engage the closed end portion of the bag, such that the bag is held by the vacuum gripping device to an extent sufficient to allow the vacuum gripping device to lift or move the bag, wherein the optical device (202a, 202b) is configured to capture an image of the optically readable element, wherein the optical device is configured to capture 3D data of the one of said bags, the bag being filled with contents to at least 10 % of its volume, preferably at least 25 % or at least 50 %, and wherein the processor is configured to identify a position and orientation of the closed end portion, and to control the vacuum gripping device to engage the closed end portion.

2. The system as claimed in claim 1, wherein the processor is configured to control the gripping device so as to raise the closed end portion to an extent sufficient to cause evacuation of the contents from the bag.

3. The system as claimed in claim 1 or 2, further comprising a conveyor (205) for transporting the bag on a conveyor, wherein the optical device is configured to capture the image and the 3D data while the bag carried on the conveyor.

4. The system as claimed in claim 3, further comprising transporting the bag on the conveyor (205), wherein the processor is configured to control the vacuum gripping device to engage the closed end portion while the bag is carried on the conveyor.

5. The system as claimed in any one of the preceding claims, wherein the vacuum gripping device (204) comprises a pressure sensor (2046), arranged to measure a pressure inside a suction chamber (2042) and to provide pressure data to the control device, and wherein the control device is configured to determine whether a sufficient engagement with the bag has been achieved based on said pressure data.

6. A method of gripping a bag, comprising: providing a disposable waste bag (100) comprising an open end portion (2), a closed end portion (1), spaced from the open end portion, as seen in a longitudinal direction of the bag (100), a wall, extending between the closed end portion and the open end portion, and characterized by an optically readable element (3) arranged on the wall of the bag, which optically readable element represents information of a relative position of at least the closed end portion, the bag being filled with contents to at least 10 % of its volume, preferably at least 25 % or at least 50 %, arranging the bag on a conveyor (205), capturing an image of at least the wall of the bag, said image depicting an optically readable element, which represents information of a relative position of at least the closed end portion, capturing 3D data of the bag, using the image including the optically readable element and the 3D data to determine a spatial position and orientation of the closed end portion, and controlling a vacuum gripping device to engage the closed end portion.

7. The method as claimed in claim 6, wherein capturing 3D data comprises laser scanning, e.g. by a line laser.

8. The method as claimed in claims 6 or 7, wherein capturing the image comprises scanning, e.g. by one or a plurality of cameras.

9. The method as claimed in any one of the 6-8, wherein the captured 3D data comprises stereo images.

10. The method as claimed in any one of the claims 6-9, further comprising moving the bag by means of a conveyor after the vacuum gripping device engaging the closed end portion.

11. The method as claimed in any one of claims 6-10, wherein the vacuum gripping device is controlled to lift the closed end portion upwardly.

12. The method as claimed in any one of claims 6-11, wherein the contents comprises a plurality of individual bags having a smaller volume than the bag, and wherein the smaller bags are evacuated from the bag and transported to a sorting station, where the bags are sorted into at least two fractions depending on a parameter that is derivable from said bags.

13. A method of emptying a bag, comprising: providing a disposable waste bag comprising an open end portion (2), a closed end portion (1), spaced from the open end portion, as seen in a longitudinal direction of the bag (100), a wall, extending between the closed end portion and the open end portion, and characterized by an optically readable element (3) arranged on the wall of the bag, which optically readable element represents information of a relative position of at least the closed end portion, the bag being filled with contents to at least 10 % of its volume, preferably at least 25 % or at least 50 %, arranging the bag on the conveyor, capturing an image of at least a first portion of the bag, said image depicting the optically readable element, capturing 3D data of the bag, using the image and the 3D data to determine a spatial position and orientation of a closed end portion of the bag, controlling a vacuum gripping device to engage the closed end portion, and moving the closed end portion relative to the contents such that the contents are evacuated from the bag.

14. The method as claimed in claim 13, further comprising moving the bag by means of a conveyor after the vacuum gripping device has engaged the closed end portion.

15. The method as claimed in claim 13 or 14, wherein the vacuum gripping device is controlled to lift the closed end portion upwardly.

16. The method as claimed in any one of claims 13-15, wherein the contents comprises a plurality of individual waste bags having a smaller volume than the bag, and wherein the smaller waste bags are evacuated from the bag and transported to a sorting station, where the smaller bags are sorted into at least two fractions depending on a parameter that is derivable from said bags.

17. The method as claimed in any one of claims 14-16, further comprising measuring a pressure inside a suction chamber (2042) of the vacuum gripping device, and to determine whether a sufficient engagement with the bag has been achieved based on pressure data provided through said measuring.

18. A method of processing a bag, comprising: providing a disposable waste bag comprising an open end portion (2), a closed end portion (1), spaced from the open end portion, as seen in a longitudinal direction of the bag (100), a wall, extending between the closed end portion and the open end portion, and characterized by an optically readable element (3) arranged on the wall of the bag, which optically readable element represents information of a relative position of at least the closed end portion, the bag being filled with contents to at least 10 % of its volume, preferably at least 25 % or at least 50 %, transporting the bag on a first conveyor section, capturing a first image of at least a first portion of the bag, said first image depicting the optically readable element, capturing 3D data of the bag, using the first image and the 3D data to determine a spatial position and orientation of the closed end portion of the bag, controlling a first vacuum gripping device to engage the bag, lifting the bag to a second conveyor section, transporting the bag on the second conveyor section, capturing a second image of at least the first portion of the bag, said second image depicting the optically readable element, capturing 3D data of the bag, using the second image and the 3D data to determine a spatial position and orientation of the closed end portion of the bag, controlling a second vacuum gripping device to engage the closed end portion, and moving the closed end portion relative to the contents such that the contents are evacuated from the bag.

19. The method as claimed in claim 18, wherein the first and second conveyor sections are movable independently of each other.

20. The method as claimed in claim 18 or 19, wherein the first and second conveyor sections are separated by a gap.

21. The method as claimed in any one of claims 18-20, further comprising transferring a non-identifiable item from the first conveyor section to a third conveyor section.

22. The method as claimed in claim 21, wherein the non-identifiable item is transferred by gravity.

23. A system for processing waste, comprising: a plurality of bags (100), each comprising an open end portion (2), a closed end portion (1), spaced from the open end portion, as seen in a longitudinal direction of the bag (100), a wall, extending between the closed end portion and the open end portion, and characterized by an optically readable element (3) arranged on the wall of the bag, which optically readable element represents information of a relative position of at least the closed end portion, each bag being filled with contents to at least 10 % of its volume, preferably at least 25 % or at least 50 %, a first conveyor section, adapted for transporting the bags, a second conveyor section, adapted for transporting the bags, a first gripping system comprising a first optical device (202a, 202b), for capturing 3D data of the bag and for capturing an image of the wall of the bag, said image depicting the optically readable element, which represents information of a relative position of at least the closed end portion of the bag, a first control device (300), comprising a first processor arranged to perform the following steps: using the captured 3D data and the captured image to determine a spatial position and orientation of the closed end portion of the bag, and controlling a first vacuum gripping device to engage the bag on the first conveyor section, such that the bag is held by the vacuum gripping device to an extent sufficient to allow the vacuum gripping device to lift the bag onto the second conveyor section, a second gripping system comprising a second optical device (202a, 202b), for capturing 3D data of the bag and for capturing an image of the wall of the bag, said image depicting the optically readable element, which represents information of a relative position of at least the closed end portion of the bag, a second control device (300), comprising a second processor arranged to perform the following steps: using the captured 3D data and the captured image to determine a spatial position and orientation of the closed end portion of the bag, and controlling a second vacuum gripping device to engage the closed end portion of the bag, such that the bag is held by the vacuum gripping device to an extent sufficient to allow the vacuum gripping device to lift or move the bag.

24. The system as claimed in claim 23, wherein the first and second conveyor sections are movable independently of each other.

25. The system as claimed in claim 23 or 24, wherein the first and second conveyor sections are separated by a gap.

26. The system as claimed in claim 25, further comprising a third conveyor section, which is situated below said gap, such that items falling into said gap are received by the third conveyor section.