Method for robot-assisted sewing of a plurality of fabric layers

Abstract

The present disclosure relates to a method for robot-assisted sewing of fabric layers for clothing. The method comprises gripping a first fabric layer by a handling mechanism of a handling robot with an effector for handling fabric layers. The first fabric layer is positioned above a second fabric layer and the first fabric layer is fixed with the second fabric layer to form a fabric layer stack by means of a fixing mechanism which is arranged at least partially at the effector in such a way that a joining region of the first fabric layer rests on a further joining region of the second fabric layer. Furthermore, the fabric layer stack is fed to a sewing machine by means of the handling mechanism. The joining regions are sewn. The sewn fabric layer stack is fed by means of the handling mechanism.

Description

[0001] This application is a national US phase of PCT / EP2024 / 065623 which claims the benefit of the filing date of the German Patent Application No. 10 2023 114 965.2 filed 7 Jun. 2023, the disclosure of which is hereby incorporated herein by reference.TECHNICAL FIELD

[0002] The present disclosure relates to a method and a system for robot-assisted sewing of fabric layers.BACKGROUND OF THE DISCLOSURE

[0003] In the technical field of textile processing, it is an aim to increase the degree of automation in order to reduce personnel costs and correspondingly production costs.

[0004] A textile processing system which is designed, for example, for automated sewing requires a handling mechanism in order to singulate the fabric from a stack and to feed it in sufficient proximity to a sewing system (or a sewing machine) after manipulation. For this purpose, robots with an effector on which corresponding gripping mechanisms for gripping the textile piece are arranged are used. However, fabric parts which represent a piece of clothing have different sizes and can have different properties (thickness, air permeability, stiffness, etc.) both among one another and within the same piece.

[0005] During the sewing with a sewing machine, two fabric layers placed one above the other are moved relative to the sewing machine in order to produce a seam. The fabric layers can be moved by the sewing machine itself or by means of a special guide unit which guides the fabric layers relative to a sewing machine. Before and after the sewing operation, the fabric layers must be fed and removed with further handling elements. Therefore, a longer set-up time must be accepted before the sewing operation and after the sewing operation until a sewing operation can start.SUMMARY OF THE DISCLOSURE

[0006] There may be a need to increase the efficiency of an automatic sewing operation.

[0007] This need is met with a method and a system for robot-assisted sewing of fabric layers according to the subject matter of the independent patent claims.

[0008] According to a first aspect of the present disclosure, a method for robot-assisted sewing of fabric layers for clothing is described. The method comprises gripping a first fabric layer by a handling mechanism of a handling robot with an effector for handling fabric layers. The first fabric layer is positioned above a second fabric layer which rests on a worktable and the first fabric layer is fixed with the second fabric layer to form a fabric layer stack by means of a fixing mechanism which is arranged at least partially at the effector in such a way that a joining region of the first fabric layer rests on a further joining region of the second fabric layer. Furthermore, the fabric layer stack is fed to a sewing machine by means of the handling mechanism, wherein the joining regions are freely accessible for the sewing machine. The joining regions are sewn, wherein during the sewing the handling mechanism guides the fabric layer stack relative to the sewing machine. The sewn fabric layer stack is fed by means of the handling mechanism from the sewing machine to a depositing location.

[0009] According to a further aspect, a system for robot-assisted sewing of fabric layers for clothing is described. The system comprises a handling robot with an effector, which comprises a handling mechanism for handling fabric layers, wherein the handling mechanism is configured to grip a first fabric layer. The handling mechanism is configured to position the first fabric layer above a second fabric layer which rests on a worktable.

[0010] The system furthermore comprises a fixing mechanism which is arranged at least partially at the effector, wherein the fixing mechanism is configured to fix the first fabric layer and the second fabric layer to one another to form a fabric layer stack in such a way that a joining region of the first fabric layer rests on a further joining region of the second fabric layer. Furthermore, the system comprises a sewing machine. The handling mechanism is configured to feed the fabric layer stack to the sewing machine, wherein the joining regions are freely accessible for the sewing machine. The sewing machine is configured to sew the joining regions, wherein the handling mechanism is configured to guide the fabric layer stack relative to the sewing machine during the sewing.

[0011] The handling mechanism is configured to convey the sewn fabric layer stack from the sewing machine to a depositing location.

[0012] The handling robot comprises the effector on which the corresponding handling mechanism is, in particular exchangeably, attached. The handling robot is fastened with a stationary robot base on the floor or on the worktable in order to introduce corresponding forces into the corresponding system. Alternatively, the handling robot is also configurable such that the robot base is configured to be movable along the floor. A robot arm can be arranged between the effector and the robot base, which robot arm comprises, for example, one or more joints in order thus to control the effector into a desired position.

[0013] The handling robot is a programmable multi-purpose handling device for moving material, workpieces, tools or special devices. In particular, the handling robot is configured to handle or manipulate the fabric layers and to move and position them accordingly. In other words, the handling robot enables a machine-controlled position change possibility in more than one axis and / or along a translational position change of the fabric layers.

[0014] The term fabric layer denotes the possible textiles or textile parts of a textile product, in particular a piece of clothing. The term fabric layer includes different knitted forms, in particular woven and non-woven fabrics. The left / left side of a fabric layer denotes the inner side (i.e. the fabric underside, fabric inner side or the “not beautiful side” of a fabric layer). In the case of a piece of clothing, the left side corresponds to the non-visible side of the fabric layer. The “beautiful side” of a fabric or fabric layer is used as the right / right side of a fabric layer (e.g. the fabric upper side, visible side, fabric outer side). In the case of a piece of clothing, the right side corresponds to the visible side of the fabric or the fabric layer (e.g. the outer side of a T-shirt). Furthermore, a fabric part can consist of a plurality of fabric layers. For example, a fabric part (such as a piece of clothing) can be folded several times and can rest on a worktable as a fabric layer stack with a plurality of fabric layers. Alternatively, the fabric layers can each represent separate fabric parts which form a fabric layer stack one above the other.

[0015] A joining region of a fabric layer describes a region which is to be processed using a sewing machine. For example, the joining region can be that region of a fabric layer at which a seam or a seam can run. In particular, joining regions of two fabric layers lying one on top of the other are laid one above the other so that they can be connected by means of the sewing machine (for example by means of sewing or welding).

[0016] The controllable handling mechanism and the fixing mechanism are arranged at the effector. The fixing mechanism is configured to fasten at least two fabric layers which in particular lie one on top of each other so that the fixed two fabric layers can be conveyed in particular as a package or as a fabric layer stack.

[0017] In particular, the handling mechanism can convey a fabric layer or the described fabric layers fixed together, for example to the sewing machine. The effector or the handling mechanism can adapt to the contour of the fabric layers, for example by fixing points of the handling mechanism being adjustable at which the fabric layer is fixed. For example, the fixing elements described below can be arranged for this purpose in which the individual fixing points are formed. The handling mechanism covers in particular the contour-relevant points of a contour of the fabric layer, wherein preferably an edge of the fabric layers remains free as a joining region and is not covered by the handling mechanism. The region of the fabric layers which is covered by the effector or the handling mechanism for fixing the fabric layers is referred to below as the effector contour.

[0018] The fixing mechanism is arranged completely at the effector in an exemplary embodiment. For example, however, a part of the fixing mechanism can also be arranged at a worktable on which, for example, the fabric layers are placed. Correspondingly, the handling mechanism is fastened completely to the effector, but a part of the handling mechanism can also be fastened to the worktable. In exemplary embodiments, functional elements of the fixing mechanism can form elements of the handling mechanism and vice versa. For example, a holding needle device or suction device of the fixing mechanism can fix a plurality of fabric layers, but can also hold the fabric layer stack thus formed at the effector, with the result that the function of the handling mechanism is likewise fulfilled.

[0019] The effector thus forms an end part of the handling robot with, for example, grippers as a handling mechanism which grip and manipulate a fabric layer (for example a planar, unprocessed fabric layer or an entire piece of clothing as a fabric layer) or a fabric layer stack which consists of fabric layers which are fastened by the fixing mechanism.

[0020] For example, the sewing machine can connect two fabric layers to each other, with the result that a seam is produced. For example, the seam describes the connection of two fabric layers by means of a thread or yarn, wherein at least the one material substantially represents a fabric, a non-woven fabric or a woven fabric.

[0021] For automatic packaging of textile products, the connection of two fabric layers is a basic requirement for many products, in particular in the production of pieces of clothing. For this purpose, according to the disclosure, two fabric layers can be exactly placed by means of the handling mechanism, with the result that the joining regions lie exactly one on top of the other and are fixed by means of the fixing mechanism. In order that a plurality of fabric pieces can be precisely stacked one on top of the other with the effector and then fixed for further processing, the effector according to the disclosure allows a depositing of a first fabric layer on a surface of a worktable, a precicely aligning and depositing a further fabric layer on the fabric layers already lying on the worktable, and a fixing of the two fabric layers by means of the fixing mechanism. By means of the handling mechanism, a “repositioning of a fabric layer” and “stacking” can be enabled.

[0022] An effector / gripper system according to the disclosure equipped in this way is capable of stacking fabric layers exactly one on top of each other, with the result that these two fabric layers can then be joined. However, a fabric part can thus also be folded with the folding device (German: Umlegevorrichtung) described below, with the result that two fabric layers are produced therefrom, which can then be fixed and further processed (e.g. fold seam). In order to fix the two fabric layers on top of each other, preparing measures can at best already be performed with the system before the placement, these can encompass folding (see the folding device described below), or adding (of an adhesive), introducing (auxiliary material for ultrasonic welding), etc., which is enabled with the fixing mechanism. Such a preparing action is enabled according to the disclosure with an additional device or fixing mechanism which is installed either at the effector or at the worktable.

[0023] With the method according to the disclosure and the system, the fabric layers can be held at the same effector by means of the handling mechanism during the entire handling process before the sewing and after the sewing. Thus, no changeover (German: Umrüsten) between a feeding device before the sewing and a device after the sewing is necessary. Since the fabric layers are held together by means of the fixing mechanism before and while the sewing, and the handling mechanism fastens the fabric layers to the effector before, during and after the sewing, no further conveying unit is necessary, with the result that a more efficient sewing process can be provided.

[0024] According to a further exemplary embodiment of the method, the handling mechanism singulates the second fabric layer from a plurality of fabric layers and deposits it in a flat manner on a work surface of the worktable, so that subsequently the first fabric layer is positioned above the second fabric layer. In other words, a singulation of a fabric layer from a fabric layer stack is thus carried out and subsequently it is placed in a flat manner on the work surface. Subsequently, a second fabric part is gripped with the handling mechanism and placed on the second fabric layer with a defined overlap, in particular of the joining regions. This has the advantage that the effector can place the second fabric layer on a layer whose location is already precisely known (e.g. from a previous placing step).

[0025] According to a further exemplary embodiment, the first fabric layer and the second fabric layer form regions of a fabric part, wherein the positioning of the first fabric layer above the second fabric layer is carried out by folding the fabric part, in particular by means of a folding device which is configured to fold an edge region of the fabric part in such a manner that the folded edge region forms the first fabric layer which rests on the second fabric layer. In particular, a projection of a fabric layer which projects beyond the effector or the effector contour is folded by means of a seam folder (folding device). This has the advantage that the fabric part only has to be gripped once by means of the handling mechanism (e.g. during the singulation) and thus a higher positional reliability prevails, which contributes to a reduced error rate and reduces the tendency to folds. The folding device is configured to fold an edge region of a fabric layer in such a manner that the folded edge region forms the first fabric layer which rests on the second fabric layer. The folding device is arranged in particular at the work table. The folding device comprises a clamping device which is provided at the effector or at the work table and which is configured in provided at the effector in order to clamp the folded first fabric layer and the second fabric layer together.

[0026] According to a further exemplary embodiment, the first fabric layer is fixed with the second fabric layer by means of temporary fixing elements, in particular holding needles, which are removed during sewing, in particular taking into account the sewing progress, or after sewing.

[0027] According to a further exemplary embodiment, a work surface of the worktable comprises adhesion regions with different static friction. The handling mechanism takes into account the different adhesion regions for aligning the first fabric layer, the second fabric layer or the fabric layer stack when positioning the first fabric layer, the second fabric layer or the fabric layer stack. The adhesion of the adhesion regions can in particular be controllable in an exemplary embodiment. The worktable can comprise zones of different friction / adhesion. This difference can be permanent or switchable / regulatable and thus temporary. It can thus be advantageous if the lower fabric layer does not slip during the precise placement for the fixing because it has a high friction / adhesion with respect to the work surface (while the upper fabric layer is placed thereon). If both layers are then fixed by means of the fixing mechanism, the robot can lift the fabric layers by means of the handling mechanism and reposition them into a region with better sliding capacity for the sewing or the adhesion to the work surface can be switched off.

[0028] According to a further exemplary embodiment, the sewing machine comprises a sewing foot with a sewing foot length in the conveying direction of the fabric layers to be sewn, wherein a sewing foot length in the conveying direction is larger than 20 mm, larger than 40 mm, or larger than 60 mm. Such a long sewing foot additionally prevents a rolling up of the fabric layers to be sewn and leads to the fabric layers being present in a flat and fold-free manner for sewing on the sewing machine and sliding into the sewing region of the sewing machine. The sewing foot smooths the fabric layers during the sewing. At the same time, the sewing foot generates a pressure on the underlying fabric layers. The fabric layers are fixed between the sewing foot and a lower part of the sewing machine, e.g. a transport element for the fabric layers, lifted and transported further stitch by stitch. In addition, a negative pressure region can be provided at the work table in the conveying direction in front of the sewing foot of the sewing machine in order to smooth the fabric layers in front of the sewing machine.

[0029] In particular, the sewing region on which the fabric layers rest during the sewing has a smoother surface of the work table than a rougher surface of the work table at a region in which the first fabric layer is positioned on the second fabric layer.

[0030] According to a further exemplary embodiment, the handling mechanism moves the fabric layer stack over the adhesion regions such that the position of the lower second fabric layer is adjusted to the first upper fabric layer due to the static friction to the adhesion region.

[0031] In an exemplary embodiment, the roughness of a surface of the work table can be adjusted by providing, for example, retractable and extendable bristles (German: Borsten). The bristles can extend at right angles to the surface of the work table. In addition or alternatively, bristles can have an angle of less than 90° to the surface of the work table. Thus, a different friction can be adjusted depending on the direction of movement of the fabric layers over the bristles. In an exemplary embodiment, a control unit can control the extension (German: Ausfahren) of the bristles. Furthermore, in a further exemplary embodiment, the angle of the bristles can be adjusted in order to thus adjust the friction and in particular the direction of friction with respect to the fabric layers via the bristles.

[0032] For example, oblique receiving bores can be drilled or punched into the surface of the work table, which can receive correspondingly oblique bristles (alternatively, for example, obliquely positioned tips or microneedles can be used). Alternatively, the bristles can be correspondingly adhesively bonded to a surface or corresponding bristles can be produced from plastic by means of a injection molding method. Very fine structures can be produced by means of brushing, grinding, engraving or etching of the surface. Moving or flexing fabric layers over such a surface leads to a preferential movement in one of the coordinate directions along the work table (X, Y), which can be used for tensioning or smoothing fabric layers and / or for reducing fold formation. This effect can also be achieved with other manufacturing techniques. For example, a grating device (German: Raffeleinrichtung) with elastic and / or movable lamellae can be used on the surface of the work table, which lamellae, however, consist of softer materials and the fabric layer is not moved “against the line” (German: “gegen den Strich”), but only leads to smoothing of the fabric with slight pressure of the fabric layer on the gathering device.

[0033] According to a further exemplary embodiment, during the sewing the handling mechanism moves the fabric layer stack with a first feed motion relative to the sewing machine, wherein the sewing machine moves the fabric layer stack with a second feed motion. The handling mechanism in particular controls the first feed motion differently to the second feed motion of the sewing machine. It has proven advantageous to control the feed motion of the effector or of the handling mechanism (which guides the fabric layers) differently to the feed motion of the sewing machine, in particular during the sewing process. Thus, for example, a certain tension can thereby be adjusted for the sewing between the first and the second fabric layer or a quilling formation (German: Ruschenbildung) (that is to say a fabric layer forms loops on the other fabric layer, which remains fold-free and tensioned, or one fabric layer is tensioned or stretched in relation to the other) can be supported. Moreover, distance and movement differences between the handling robot and the sewing machine can thus be adapted, in particular with a time delay.

[0034] According to a further exemplary embodiment, after the step of sewing the method comprises gripping a third fabric layer by the handling mechanism. Furthermore, the third fabric layer is positioned above the sewn first and second fabric layers which rest on a worktable. The third fabric layer is fixed with the sewn first and second fabric layers to form a fabric layer stack by means of the fixing mechanism in such a way that a further joining region of the third fabric layer rests on a further joining region of the first and / or second fabric layer.

[0035] Subsequently, this fabric layer stack is fed to the sewing machine by means of the handling mechanism and the further joining regions are sewn, wherein during the sewing the handling mechanism guides the fabric layer stack relative to the sewing machine. Three layers can thus be sewn to each other, e.g. when sewing a label into a seam. For example, first a label is sewn as a first fabric layer on a second fabric layer, only then the third fabric layer is placed and the step of sewing is repeated. This allows a more precise label placement and reduces slip problems with respect to fixing of three fabric layers.

[0036] According to a further exemplary embodiment, the fixing mechanism fixes the first and second fabric layers along at least one (continuously running) fixing region and / or along a plurality of spaced-apart fixing regions.

[0037] According to a further exemplary embodiment, the fixing regions have an area of less than 1 cm2, in particular less than 20 mm2, in particular less than 8 mm2. Additionally or alternatively, the fixing regions are in particular spaced apart by more than 2 cm, in particular by more than 3 cm or by more than 4 cm. Thus, a good fixing between two fabric layers can be achieved without a nonstop continuous temporary fixing path having to be produced with the fixing mechanism.

[0038] According to a further exemplary embodiment, during or after sewing, at least one of the fixing regions is separated, wherein the fixing region is in particular separated with a separating speed which is coordinated with the feed motion during the sewing with the sewing machine and substantially coincides therewith. The fixing regions are at least partially removed again since they possibly lead to a hardening / stiffening of the fabric layers. Thus, for example, this fixing can take place in a region which is cut off again during or after the sewing operation. For a fixing being present as long as possible, this cutting off can also take place incrementally depending on the sewing progress.

[0039] According to an exemplary embodiment, the work surface of the work table is movably mounted and moved, wherein in particular the movement of the work surface takes place synchronously or in coordination with the movement of the effector. The movement of the work surface takes place in particular during the sewing, wherein the work table comprises in particular a conveyor belt as work surface for conveying at least one fabric layer deposited thereon relative to the sewing machine. In an exemplary embodiment, in particular the movement of the work surface, the handling mechanism and the feed motion of the sewing machine are synchronized (in particular by means of the control unit).

[0040] Thus, a more exact control during the sewing and accordingly a sewing quality (in particular with only weak fixing of the two fabric layers) can be achieved by bilateral transport, i.e. by moving the work surface from below and the movement of the handling mechanism from above. Thus, the work surface can be movably mounted on the work table or the entire work table can be moved. This can be achieved, for example, in that the work surface consists of a conveyor belt. The two fabric layers are precisely positioned and stacked thereon and then pressed on with the effector. If this is implemented with the relevant projection outside the effector contour according to the disclosure, the conveyor belt can move past the sewing machine and at the same time the effector can support the movement synchronously from above. The effort for more complex fixings can thus be reduced and it is nevertheless ensured that no slip of the two fabric layers occurs. The work surface can additionally be equipped with an increased frictional resistance (e.g. ‘no slip’ surface). This embodiment variant is advantageous if the processed fabric comprises a strongly adhering surface or decoration (e.g. rubber covering). Without this displacement support, there can be the risk that the adhesion on the sliding surface during the sewing process is stronger than the fixing, which can lead to warping or a poor seam quality.

[0041] According to a further exemplary embodiment, the handling mechanism comprises an effector contour, wherein one of the fabric layers or the fabric layer stack can be fastened within the effector contour. The effector contour is smaller than an outer contour of the fabric layer or the fabric layer stack. The handling mechanism is configured such that the joining regions of the fabric layers form a projection with respect to the effector contour by more than 0.5 cm, in particular by more than 1 cm, further in particular by more than 2 cm or by more than 3 cm.

[0042] The effector contour describes the region on a fabric layer at which the fixing mechanism and / or the handling mechanism exerts a fixing force or holding force. The effector contour is defined, for example, by the border of the fixing surface or by the connecting lines between the individual fixing points at which a holding contact with a held fabric layer is present within the x-y plane. The connecting lines form an effector contour within the fabric layer. In the inner holding region, the fabric layer can be spanned and thus defines the x-y plane. At the outer edge regions of the fabric layers which lie outside the effector contour which is defined by the fixing points, the joining regions are formed and the fabric layer can be present untensioned there and project so to speak out of the x-y plane.

[0043] As a result of the fabric projection thus produced, a subsequent sewing is facilitated since the sewing machine reaches the joining regions more easily. This projection can then be placed on at least one other free fabric region or joining region of the further fabric layer. Alternatively, the projection can be manipulated such that it is folded (e.g. for a seam) and thus form the first fabric layer and the second fabric layer from a fabric part.

[0044] According to a further exemplary embodiment, the handling mechanism introduces holding needles with a predetermined penetration depth and / or a predetermined penetration angle into the first fabric layer or the fabric layer stack by a holding needle device for fastening to the effector. The predetermined penetration depth and / or the predetermined penetration angle can be determined in particular in real time and / or based on a sensor feedback. The holding needles can in particular have a diameter of less than 1300 micrometers, less than 900 micrometers, in particular less than 550 micrometers, further in particular less than 250 micrometers. Thus, for example, a holding needle can be inserted into the fabric part during transport at a shallow angle or not so deep, while after positioning on another fabric part a steeper angle or a larger penetration depth is used to fix both parts.

[0045] By means of the holding needle device, either from the effector side, from the worktable side or from an auxiliary system (e.g. auxiliary plate, needle band), one or more needle-like pins or holding needles can be driven from a magazine into or through the fabric layers in order to fasten them to each other. The holding needle device comprises in particular a feeding device, for example a holding needle magazine, which is configured to feed holding needles for the holding needle device.

[0046] According to a further exemplary embodiment, at least one of the fabric layers is fixed at the work surface by means of a hold-down device on the work table. The hold-down device is configured to selectively fix at least one of the fabric layers at the work table, in particular by means of pneumatic, mechanical, magnetic and / or electrostatic holding forces. The hold-down device can press with a force against the work table / the work surface, which leads to a fixing of the two intermediate fabric layers. Alternatively, the effector can also allow compressed air to flow in between its underside and the fabric layers. This is in particular helpful when the effector has to reposition itself so that it can quickly overcome the adhesive forces between the effector and the first fabric layer.

[0047] The hold-down device is in particular configured to fix the fabric layers until the fixing mechanism takes over the fixing of the two fabric layers. Furthermore, for example, a ferromagnetic support plate can lie on the work table, on which a fabric part is deposited. After a fabric layer of this fabric part has been folded or after a further fabric layer has been placed, the effector can attract the support plate by means of a magnet (in particular an electromagnet) and thus fix the fabric layers in between. Alternatively, an electrostatic holding mechanism can be used both on the worktable side and on the effector side. This helps in particular with the exact placement of two fabric layers one above the other. After the placement, the effector can then reinforce the fixing in such a way that two fabric layers are held securely and a hold-down device installed in the table can be switched off.

[0048] The work surface is in particular embedded in the work table and the work surface is in particular configured as a work plate with a thickness of less than 1 cm, in particular less than 5 mm or less than 3 mm, wherein the fabric layer stack is in particular deposited on the work surface such that the fabric layer stack forms a protrusion with respect to at least a part of the work surface.

[0049] The work surface can either be a fixedly mounted work table or a movable auxiliary plate (work surface), which can be moved at least in one coordinate direction. Alternatively, this auxiliary plate can also be temporarily connected to the effector and thus move simultaneously with the effector. In particular, the work surface can be partially integrated into the work table and form a surface without substantial height differences in at least one direction (and, for example, be displaceable in another direction). The work surface can also be designed to be relatively thin (i.e. technically speaking may be “of small height” in the z-direction). It is especially advantageous if the fabric stack forms a projection at least on a part of the work surface, since in this way the fabric stack including the work surface can be guided to directly pass next to the sewing system.

[0050] According to a further exemplary embodiment, fabric layer data relating in particular to fabric layer material and / or fabric layer geometry are determined. Additionally or alternatively, processing data, in particular left / right position, alignment, unfolding and / or production quality of one of the fabric layers or of the fabric layer stack are determined. Additionally or alternatively, a positioning, placement, fixing during the sewing and / or the sewing quality is determined. The collected data are evaluated for determining the quality of the sewn fabric layers. In particular, the data can be collected in a data processing unit. A control unit, which is coupled to the data processing unit, can analyze the corresponding data and initiate a corresponding control of the sewing machine or of the handling robot. In this way, a change in the reliability can be detected and communicated to a higher-level system. Thereby, for example, preventive maintenance or an adaptation of the handling parameters can be initiated. For this purpose, the system can also receive information from the sewing machine.

[0051] According to a further exemplary embodiment, the step of fixing comprises a feeding of adhesive for a temporary gluing together of the first fabric layer and the second fabric layer (in particular by means of the fixing mechanism). The adhesive can in particular contain a water-soluble polymer, in particular polyethylene glycol and / or polyvinyl alcohol, sodium thiosulfate pentahydrate, sodium acetate trihydrate, ammonium alum dodecahydrate, ureas and / or eutectic salt mixtures.

[0052] An adhesive device as a fixing mechanism for temporarily fixing the fabric layers can for example comprise an adhesive, which can be thermally activated (hot-melt adhesive principle) and then washed out during the first wash cycle. For this purpose, for example, water-soluble polymers with a relatively moderate melting point are used. Thus for example PEG (polyethylene glycol). For example, a water-soluble polymer with an increased melting temperature, for example around the 200 degrees Celsius, can form PVOH (polyvinyl alcohol) with a suitable degree of hydrolysis. Furthermore, low-melting salts, such as sodium thiosulfate pentahydrate (melting point or glass transition temperature FP 45-50 degrees Celsius) or sodium acetate trihydrate (melting point FP for example 60 degrees Celsius) or ammonium alum dodecahydrate (melting point FP for example 120 degrees Celsius). Here, the cooling and bonding is a phase transformation, which is strongly promoted by the fine fabric / fibre structure. These products are also relatively unproblematic with respect to toxicity and disposal / wash water.

[0053] The adhesive can in particular comprise a pressure-activated adhesive, a hot glue and / or a two-component adhesive, in particular that the adhesive can be removed again during and / or after a further processing step, in particular can be separated together with a material part of the first fabric layer, the second fabric layer and / or the fabric layer stack. In a further exemplary embodiment, a fast-reacting (for example pressure-activated) adhesive is used for in particular temporary fixing. One of the possible embodiments is an encapsulated superglue (German: Sekundenkleber), characterized in that the capsule breaks open under pressure. The capsule is for example composed of a stiff brittle material, such as for example glass, and is very small (capsule diameter in the micrometer range). The administration can be both as a powder of beads and also further incorporated into adhesive dots or adhesive tapes. The processing can be dry or in a conveying fluid (which supplements the superglue or alternatively is the second phase in the case of a quickly curing two-component adhesive [first phase within the capsules]). The adhesive is activated by pressure (by the effector or an additional equipment mounted on the table), fastens the two fabric layers very quickly and thus makes the desired fixing. If this takes place in the region of a section after the subsequent joining, the pollution, the “can no longer be removed” and the rigidity of this process are also not disadvantageous. Alternatively, this can also be realized with a hot glue.

[0054] Furthermore, PVOH adhesive with a low water content, i.e. liquid to low-melting, can be used as the adhesive. In addition, a urea melt with a melting point FP of for example 133 degrees Celsius can be used. In addition, eutectic salt mixtures or substance mixtures can be used as the adhesive.

[0055] In particular in the case of water-soluble polymers, good adhesive properties have been achieved. Thus for example with the product Kollisolv PEG 3350 from BASF, which melts at only 50 degrees and is readily water-soluble. In particular, the adhesives described above are also non-toxic and are permitted for medical applications, which does not give rise to any discussions with respect to human contact in clothes before washing. In addition, the adhesive bonding can take place in a region of the fabric layers which is separated in the later processing.

[0056] According to a further exemplary embodiment, during sewing a seam end is detected (for example by means of optical sensors), wherein during sewing at the seam end the feed motion of the handling device and / or of the sewing machine is changed at the seam end in order to vary a tension of the fabric layers between the sewing machine and the effector in strength and / or direction. This ensures that for example a special action can be carried out at the seam end, such as, for example, an end knot, a sealing of the seam end or a certain seam length, with the result that the thread can be cut off at the end.

[0057] According to a further exemplary embodiment, after sewing a thread with a predetermined thread length is cut off after one end of the seam, wherein the handling mechanism moves the fabric layer stack relative to a thread cutting device such that the thread length is adjustable. For example, at the end of a seam, after the last stitch has been put through, an extended thread section can be generated by means of a quick movement of the handling mechanism away from the sewing machine. In other words, for example a displacement movement can be provided for repositioning the fabric layers by means of the handling mechanism or the effector, which either guides the thread to a thread cutter (or vice versa) or it can also be easy to pull the free thread through the sewing system, with the result that a defined thread length is achieved at the end of the seam.

[0058] According to a further exemplary embodiment, a heating device for heating the fabric layers and / or a moistening device for moistening the fabric layers is arranged at the work table in order to smooth, in particular iron, at least one of the fabric layers and / or the fabric layer stack. Additionally or alternatively, to carry out the smoothing action, the effector can comprise a smoothing plate, in particular a heatable smoothing plate, and can be configured such that smoothing can be carried out by pressing the smoothing plate onto the fabric layer.

[0059] According to a further exemplary embodiment, a further sewing device is arranged at the work table so that during or after sewing the joining regions the further sewing device sews further joining regions of the first and second fabric layers. The sewing device and the further sewing device in particular form different sewing seams, in particular an overlock seam and a coverstitch seam, in the joining regions. It is efficient if the handling robot carries out more than one activity or operates a plurality of sewing devices by means of a held fabric layer stack on the basis of position knowledge. For this reason, it is advantageous if more than only one sewing system is available within the work region of the handling robot. On the one hand, different tasks (sewing two fabrics together and sewing a seam) can thus be carried out without making large interruptions necessary because of a resumption of the fabric layers, on the other hand, the thread breakage of a machine can thus also be compensated for by the use of an alternative machine. In particular, it can be advantageous if these sewing systems are different because in this way different tasks can be achieved without re-gripping of the effector. For example, if one sewing system can carry out overlock seams (at best with cutting off the projection) and the other sewing system can carry out coverstitch seams, for example.

[0060] According to a further aspect, a program element for robot-assisted sewing of fabric layers for clothing, which program element, when executed by a processor, is configured to carry out the method described above. By means of the program element, instructions for controlling a computer system can be given in order to coordinate the carrying out of the method described above.

[0061] The computer program can be implemented as computer-readable command code in any suitable programming language, such as JAVA, C++, for example, and can be stored on a computer-readable medium (removable disk, volatile or non-volatile memory, embedded memory / processor, etc.). With the command code, a computer or another programmable device can be programmed in such a way that it carries out the intended functions. The computer program can be made available via a network, such as the World Wide Web, for example, from which it can be downloaded. The disclosure can be realized with the aid of a computer program or software. However, the disclosure can also be realized by means of one or more specific electronic circuits or hardware. Furthermore, the disclosure can also be realized in a hybrid form, i.e. in a combination of software and hardware modules.

[0062] According to a further exemplary embodiment of the system, the handling mechanism is selected from the group consisting of grippers, suction units, clamps, regions with increased friction and / or electrostatic attraction, rollers, freezing grippers, and / or Bernoulli grippers.

[0063] Electroadhesive grippers for electrostatic attraction work with electrostatic fields. Holding forces are generated by polarization. They can be generated on the upper side of the fabric layer, which is in contact with a gripper dielectric of the electroadhesive gripper.

[0064] A Bernoulli gripper has a suction body, wherein compressed air is flowed to the outside between the fabric part and the suction body along the x-y plane via a flow channel of the suction body at the edge regions of the suction body. An air opening, which is coupled to the flow channel, is located in the center of the suction body. Due to the Bernoulli effect, air is sucked into the flow channel from the direction of the fabric part. A fixing force of the fabric part on the suction body thus arises.

[0065] A freezer gripper has a strongly cooled contact surface with the fabric part, as a result of which frozen water or ice as an adhesive adheres the fabric part to the contact surface. The water can be drawn as an adhesive from the atmosphere (air humidity) or can be added by an adhesive supply.

[0066] According to a further exemplary embodiment, the handling mechanism comprises holding needles, which penetrate at least into the first fabric layer, the second fabric layer and / or the fabric layer stack in order to fasten them to the effector. Furthermore, a penetration depth and / or a penetration angle of at least one holding needle can be controllable, in particular in real time and / or based on a sensor feedback. An additional form of differentiated gripping by the handling mechanism can relate to the depth of a holding needle and / or the angle of a holding needle (and in particular a plurality thereof). Thus, for example, a holding needle can be inserted into the fabric layer during singulation at a shallow angle or not so deep, while during the fastening of two fabric layers (for the joining) a steeper angle or a larger penetration depth can be used to securely grip both fabric layers.

[0067] According to a further exemplary embodiment, holding needles have a diameter of less than 1300 micrometers, less than 900 micrometers, in particular less than 550 micrometers, further in particular less than 250 micrometers. It has been found that in the case of fine microneedles as holding needles in combination with a suitable vacuum negative pressure and a suitable air flow, no quality-disturbing effects remain on the fabric surface after the processing. This has been shown especially in the case of needle diameters of less than 1300 micrometers, less than 900 micrometers, in particular less than 550 micrometers, preferably less than 250 micrometers.

[0068] According to a further exemplary embodiment, holding needles are arranged at a control surface of the handling mechanism, wherein a surface shape of the control surface is adjustable such that in a first configuration of the surface shape the holding needles are oriented parallel to each other in order to penetrate into or move out of at least one fabric layer, and in a second configuration of the surface shape the holding needles are not oriented parallel to each other in order to fix them in at least one fabric layer.

[0069] As a result of the bending of the control surface, the holding needles spread apart and fix the two fabric layers. In the case of a bending back of the control surface, for example a uniform movement or abruptly by means of a clicking back, the holding needles, which are in particular again oriented parallel to each other, are released again from the fabric layers. By means of a handling mechanism configured in this way, in particular in the case of two-layer stacking of fabric layers, the fixing at the handling mechanism can be removed again gradually within the course of the sewing progress.

[0070] According to a further exemplary embodiment, the surface shape of the control surface is deformable and in particular pre-tensionable by means of mechanical or hydraulic elements. Furthermore, the control surface can be configured to be elastically deformable, so that it can be pre-tensioned and is automatically deformed back without an external restoring force into a starting position, for example by the holding needles running parallel or by the holding needles having an angle to each other. The control surface can move back continuously into a starting position. Furthermore, for example, the control surface can comprise a material with a memory effect, and abruptly click back or snap back into a starting position.

[0071] According to a further exemplary embodiment, the effector comprises an abutment surface within an effector contour, at which one of the fabric layers or the fabric layer stack can abut. The abutment surface in particular forms a part of the handling mechanism for fixing one of the fabric layers or the fabric layer stack, wherein the abutment surface is configured to hold one of the fabric layers or the fabric layer stack magnetically, based on air pressure, mechanically or electrostatically on the effector.

[0072] The abutment surface allows the fabric layers or the fabric layer stack to be transported in a warp- and fold-free manner and to be deposited later. After the positioning or stacking of the fabric layers, the fabric layers can be fixed more easily with the abutment surface. The abutment surface can for example be part of the magnetic device and can be configured to be correspondingly magnetic. Furthermore, the abutment surface can hold the fabric layers with negative pressure, with mechanical elements (for example continuous microneedles) or with electrostatic elements.

[0073] According to a further exemplary embodiment, the abutment surface forms a suction surface as part of the handling mechanism, at which one of the fabric layers or the fabric layer stack can abut. The suction surface comprises a plurality of suction openings, in particular more than 9, more than 15, more than 22 and / or more than 30 suction openings, wherein the suction openings are in particular configured with a diameter of less than 20 mm, in particular less than 10 mm, further in particular less than 5 mm, further in particular less than 3 mm. With a handling mechanism based on negative pressure, sufficient force can be generated with a small suction opening only with high negative pressure in order to hold the fabric layers. The fabric layer deforms, which could in particular make the ironing necessary in a next work step. On the other hand, large suction openings deform the textile material so strongly even with little negative pressure that it no longer lies sufficiently flat in the x-y plane. In addition, during the positioning on another fabric layer, the latter can also still be sucked, which counteracts the exact positioning. For this reason, a solution was selected which uses a plurality of small suction openings (which are distributed over a larger area or edge). The experiments with respect to smaller diameters of these suction openings have shown that the fabric layers hold in a planar manner in the x-y plane. This in particular prevents warping and fold formation for the later laying down.

[0074] According to a further exemplary embodiment, a negative pressure on the suction surface for holding the fabric layers or the fabric layer stack is adjustable such that the negative pressure is variable by more than 15%, in particular more than 30% or by more than 45%. In the exemplary embodiment in which the handling mechanism is implemented by means of a suction unit, a gripping function is achieved by means of negative pressure. The suction unit comprises a suction cup or a suction bell, to which a vacuum pump or a suction pump is connected in order to suck air out of the suction cup. A negative pressure is generated in the volume between the fabric part and the suction cup, with which negative pressure a fixing force is generated. The negative pressure can, for example, be measured by means of sensors in order to accordingly control the suction power by means of the control device.

[0075] The suction power or the negative pressure can be adjusted for different fabric types of the fabric parts. Good results have been achieved with the following negative pressure powers:Suction Power inSuction Power inType of fabric[Pa][mbar]Cotton 100% Interlock16020-18300160.20-183.00JerseyCotton-Tencel (66 / 33)17060-19240170.60-192.40InterlockCotton-Elastane (95 / 5)18720-22300187.20-223.00Single JerseyDenim13400-15600134.00-156.00100% Polyester - Plain25370-27800253.70-278.00weave

[0076] The control unit and the vacuum pump can be configured such that a negative pressure can vary by more than 15%, in particular more than 30%, preferably by more than 45%. A high adaptability to different fabrics is thus enabled. Furthermore, the error sources of an incorrect fixing, suction at the work table and slip during the sewing can thus be significantly reduced.

[0077] According to a further exemplary embodiment, the fixing mechanism comprises a welding device, in particular an ultrasonic welding device, for, in particular temporarily, welding together the first and second fabric layers, wherein the fixing mechanism comprises in particular a feeding device for feeding welding material. Depending on the material property, a plastic welding technique, in particular ultrasonic welding, can be used. A suitable auxiliary material (ultrasonic welding tape, hot-melt adhesive, etc.) welding material can also be inserted beforehand (or during the welding process) by means of the feeding device. Alternatively, an adhesive can be placed beforehand by means of a metering device. For example, the effector can travel to a fabric layer stack. The feeding device can for example feed a solid welding material, such as for example a welding wire, or a viscous fluid, which solidifies under the effect of heat, in particular at the joining regions of the fabric layers lying on one another in the fabric layer stack. The feeding device can for example be fastened to the worktable or to the effector. Correspondingly, the fixing mechanism comprises a heat generator of the welding element which heats the welding material in the region of the joining region in the fabric layers, with the result that a weld seam can be produced.

[0078] According to a further exemplary embodiment, the fixing mechanism comprises a suction device with at least one sucking unit, wherein the suction device is configured to suck air from the first and second fabric layers by means of the sucking unit in such a way that the first and second fabric layers lying on one another can be fixed to the suction device.

[0079] According to a further exemplary embodiment, the fixing mechanism comprises a magnetic device, which is configured to attract a magnetic element in the direction of the effector in such a way that the fabric layers, which can be arranged between the effector and the magnetic element, can be fixed. Since the fabric layers are permeable to air to a certain degree due to their material characteristic, two or more fabric layers can be fastened in a fabric layer stack by means of suction with a correspondingly adjusted suction power. The suction device comprises, for example, a vacuum pump, which can be arranged spaced apart from the effector, for example at the work table. One or more sucking units, such as suction cups, for example, can be fastened to the effector as part of the fixing mechanism. Furthermore, the suction device with the sucking units can also form parts of the handling mechanism in order to align and convey the fixed fabric layers. In an exemplary embodiment, the suction device also forms parts of the handling mechanism for handling the fabric layers.

[0080] According to a further exemplary embodiment, the fixing mechanism comprises a clamping device, which is configured to clamp the first fabric layer and the second fabric layer together.

[0081] According to a further exemplary embodiment, the fixing mechanism comprises an adhesive device, which is configured to provide a temporary gluing together of the first fabric layer and the second fabric layer. In addition, the adhesive device can comprise a heating element, such as for example a heated bar or a hot-air heater, in order for example to enable hot gluing. In particular, different adhesive materials, such as for example quick-release adhesives, contact adhesives, pressure-activated adhesives or welding adhesives (for example in the case of PVC materials) can be used.

[0082] The adhesives are configured such that an adhesive force is generated which enables a later release of the fabric layers. Furthermore, an adhesive can be configured to lose its adhesive effect under the effect of temperature or under the effect of certain radiation (for example UV radiation), with the result that the fabric layers can be released again after a joining step. Accordingly, the adhesive device can for example comprise a temperature control device or a radiation device, which is configured to release the adhesive connection. The temperature control device or the radiation device can for example be arranged at the work table. The adhesive device furthermore comprises in particular a feeding device, which is configured to provide a temporary gluing together of the first fabric layer and the second fabric layer by means of adding an adhesive.

[0083] According to a further exemplary embodiment, the fixing mechanism comprises a holding needle device, which is configured to introduce holding needles into the first fabric layer and the second fabric layer for fixing. By means of the holding needle device, either from the effector side, from the worktable side or from an auxiliary system (e.g. auxiliary plate, needle band), one or more needle-like pins or holding needles can be driven from a magazine into or through the fabric layers in order to fasten them to each other. The holding needle device comprises in particular a feeding device, for example a holding needle magazine, which is configured to feed holding needles for the holding needle device.

[0084] According to an exemplary embodiment, the fixing mechanism comprises a stapling device, which is configured to introduce at least one staple into the first fabric layer and the second fabric layer for fixing, wherein the stapling device comprises in particular a feeding device, which is configured to feed staples for the stapling device.

[0085] According to a further exemplary embodiment, the fixing mechanism comprises a hold-down device, which is configured to apply a pressing force to the first fabric layer and the second fabric layer in the direction of the work surface. The hold-down device can press with a force against the work table / the work surface, which leads to a fixing of the two intermediate fabric layers. Alternatively, the effector can also allow compressed air to flow in between its underside and the fabric layers. This is in particular helpful when the effector has to reposition itself so that it can quickly overcome the adhesive forces between the effector and the first fabric layer.

[0086] According to a further exemplary embodiment, the handling mechanism comprises a support element, in particular a support plate, for supporting the fabric layer stack to be conveyed, wherein the handling mechanism in particular is configured such that the first fabric layer and second fabric layer fixed by the fixing mechanism can be lifted together and the support element can be conveyed below the fixed first fabric layer and second fabric layer. The support element can for example have a fork shape, or the support plate can comprise a round support surface or an angular support surface. Furthermore, the support element can comprise an adhesive surface, with the result that the fabric layers do not slide down unintentionally during transport or joining. The support element can for example (e.g. via a further robot arm) be arranged in an articulated manner on the effector in order to be inserted accordingly below or between the fabric layers.

[0087] In other words, the uppermost fabric layer or the uppermost fabric layers of a fabric layer stack can thus be lifted. For this purpose, the handling mechanism can lift the uppermost fabric layer or at least one rim or one edge by means of the explained exemplary embodiments (e.g. by means of a temporary adhesive, with holding needles or microneedles, by means of a Bernoulli gripper or by means of suction devices or vacuum), with the result that the support element can be moved in between, i.e. can subsequently be transported between the uppermost fabric layer(s) and the underlying fabric layers or the work table. In other words, the support element initially moves in the x- or y-direction below the fabric layer to be lifted, with the result that at the beginning the front edge of the support element is parallel to the straight cut edge of the fabric layer. When the support element is completely (or at least) pushed under, the support element together with the fabric layer to be lifted is lifted vertically or in the z-direction and thus singulated from the rest of the underlying fabric layers.

[0088] In summary, the following process sequence can be carried out with the method according to the disclosure:

[0089] A) gripping and positioning a fabric layer by the handling mechanism of a handling robot

[0090] B) fixing two fabric layers one above the other by means of the fixing mechanism, wherein the action of the effector for the fixing by means of the fixing mechanism differs from the action for the gripping (step A) by means of the handling mechanism and the fixing by means of the fixing mechanism takes place with the aid of at least one action from the list: welding, sucking, folding, magnetically fixing, clamping, adhesive bonding, fastening, holding-down, pressing together, penetrating and / or piercing.

[0091] C) feeding the two fabric layers to a sewing machine, wherein the regions to be sewn, i.e. the joining regions, of the fabric layers form a projection,

[0092] D) sewing these fabric layers with the assistance of a continuous guidance of the handling mechanism

[0093] E) guiding the sewn parts away from the sewing machine by the handling mechanism.

[0094] The provided projection of multi-layered fabric is the requirement for subsequent automated sewing. For this purpose, the fabric stack already placed in a flat and horizontal manner is fed with the handling robot to a sewing machine (controlled by the automation system) and sewn. The handling robot guides the fabric stack in coordination with the feed motion (i.e. the forward and return transport via the sewing feet) of the sewing machine. The sewing machine can comprise both an upper transporter and / or a lower transporter (fabric transport through the stitch plate). Furthermore, the sewing machine can be equipped without a transporter. In a further exemplary embodiment, the sewing foot described above can be used as a transporter. A triple transport can also be used, in which, in addition to the upper and lower transporters, the needle is also moved along (especially in the case of stiff woven fabrics). By fixing the fabric layers and carrying along the robot (takes over the fabric weight in the case of heavy fabrics), a clean transport and thus a good seam quality can be achieved. Thus, further transport aids such as sewing in paper, powders, oils, etc. can be dispensed with. In particular, a piece of clothing can thus be produced without subsequent washing and ironing.

[0095] The guidance by the robot can, however, also allow different feeds of upper and lower fabric if the fabric layers are not fixed on top of each other but the fixing is focused on separately guidable auxiliary constructions (e.g. thin plates). Thus, on the one hand, a holding / conveying device can be installed in the work table (e.g. with electrostatic holding or electrostatic transport [similar to a linear motor]), which transports the lower fabric layer and the robot arm with the effector fixes the upper fabric layer. Thus, different travel paths for the upper and lower fabric can be guided during the sewing, which allows certain 3D effects after the sewing process. There exist sewing machines which allow this different transport of upper and lower fabric. With the solution according to the disclosure, however, correspondingly automated productions can thus be achieved. The introduction of the two fabric layers into the different transport devices of the sewing machine can be realized by separate movements of the different feeds (as explained at the beginning of this section), however, it can also be realized by different widths of a projection of a stitched double layer (and the stitching is then released, e.g. cut off, in the sewing process).

[0096] It is pointed out that the embodiments described here represent only a limited selection of possible embodiment variants of the disclosure. It is thus possible to combine the features of individual embodiments with each other in a suitable manner, with the result that a multiplicity of different embodiments are to be regarded as obviously disclosed for the person skilled in the art with the embodiment variants explicit here. In particular, some embodiments of the disclosure are described with device claims and other embodiments of the disclosure are described with method claims. However, the person skilled in the art will immediately understand when reading this application that, unless explicitly stated otherwise, in addition to a combination of features which belong to a type of subject matter of the disclosure, an arbitrary combination of features which belong to different types of subject matter of the disclosure is also possible.BRIEF DESCRIPTION OF THE DRAWINGS

[0097] Exemplary embodiments are described in more detail below with reference to the appended drawings for further explanation and for a better understanding of the present disclosure. In the drawings:

[0098] FIG. 1, FIG. 2, FIG. 3 and FIG. 4 show schematic illustrations of a method for handling and processing fabric layers according to an exemplary embodiment.

[0099] FIG. 5 shows a schematic illustration of a handling mechanism which holds a fabric layer stack within an effector contour.

[0100] FIG. 6 shows a schematic illustration of a magnet device as a fixing mechanism according to an exemplary embodiment.

[0101] FIG. 7 shows a schematic illustration of an effector with a contact surface according to an exemplary embodiment.

[0102] FIG. 8 shows a schematic illustration of an effector with a handling mechanism and a fixing mechanism according to an exemplary embodiment.

[0103] FIG. 9 shows a schematic illustration of a worktable with adjustable static friction on the work surface according to an exemplary embodiment.

[0104] FIG. 10 shows a schematic illustration of a handling mechanism with a gripping device according to an exemplary embodiment of the present disclosure.

[0105] FIG. 11 shows a schematic illustration of a handling mechanism with a suction device according to an exemplary embodiment of the present disclosure.

[0106] FIG. 12 shows a schematic illustration of a handling mechanism with an electrostatically charged element according to an exemplary embodiment of the present disclosure.

[0107] FIG. 13 shows a schematic illustration of a handling mechanism with holding needles according to an exemplary embodiment of the present disclosure.

[0108] FIG. 14 shows a schematic illustration of an effector with a plurality of different handling mechanisms, for example with a suction device and holding needles according to an exemplary embodiment of the present disclosure.

[0109] FIG. 15 shows a schematic illustration of a handling mechanism with a gripper, which grips an upper side of a fabric layer, according to an exemplary embodiment of the present disclosure.

[0110] FIG. 16 shows a schematic illustration of a handling mechanism with a suction surface according to an exemplary embodiment of the present disclosure.

[0111] FIG. 17, FIG. 18 and FIG. 19 show schematic illustrations of a fixing mechanism with a folding device according to an exemplary embodiment of the present disclosure.

[0112] FIG. 20 shows a schematic illustration of the folding device, which is arranged on a worktable, according to an exemplary embodiment of the present disclosure.

[0113] FIG. 21 shows a schematic illustration of fabric layers with a protrusion outside an effector contour, according to an exemplary embodiment.

[0114] FIG. 22, FIG. 23 and FIG. 24 show schematic illustrations of a handling mechanism with holding needles according to an exemplary embodiment.

[0115] FIG. 25 shows a schematic illustration of a positioning of a third fabric layer on two already sewn fabric layers according to a further exemplary embodiment.DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

[0116] Identical or similar components in different figures are provided with identical reference numerals. The illustrations in the figures are schematic.

[0117] FIG. 1, FIG. 2, FIG. 3 and FIG. 4 show schematic illustrations of a method for robot-assisted sewing of fabric layers 111, 112 for clothing. The method comprises gripping a first fabric layer 111 or second fabric layer 112 by a handling mechanism 120 of a handling robot 100 with an effector 101 for handling fabric layers 111, 112 (see FIG. 1). The first fabric layer 111 is positioned above a second fabric layer 112 which rests on a worktable 103 (see FIG. 2) and the first fabric layer 111 is fixed with the second fabric layer 112 to form a fabric layer stack 113 by means of a fixing mechanism 130 which is arranged at least partially at the effector 101 in such a way that a joining region 114 of the first fabric layer 111 rests on a further joining region 115 of the second fabric layer 112 (see FIG. 3). Furthermore, the fabric layer stack 113 is fed to a sewing machine 140 by means of the handling mechanism 120, wherein the joining regions are freely accessible for the sewing machine 140. The joining regions are sewn, wherein during the sewing the handling mechanism 120 guides the fabric layer stack 113 relative to the sewing machine 140 (see FIG. 4). The sewn fabric layer stack 113 is fed by means of the handling mechanism 120 from the sewing machine 140 to a depositing location.

[0118] The handling robot 100 comprises the effector 101 on which the corresponding handling mechanism 120 is, in particular exchangeably, attached. The handling robot 100 is fastened with a stationary robot base on the floor in order to introduce corresponding forces into the floor. A robot arm 104 is arranged between the effector 101 and the robot base, which robot arm comprises, for example, one or more joints in order thus to control the effector 101 into a desired position. In particular, the handling robot 100 is configured to handle or manipulate the fabric layers 111, 112 and to move and position them accordingly.

[0119] The handling robot 100 and the corresponding handling mechanism 120, the fixing mechanism 130 and / or the sewing machine 140 (or another joining unit) are coupled by means of a control unit 105, such that fully automatic positioning of the fabric layers 111, 112 and subsequent joining can be carried out.

[0120] The controllable handling mechanism 120 and the fixing mechanism 130 are arranged at the effector 101. The fixing mechanism 130 is configured to fasten at least two fabric layers 111, 112 which in particular lie one on top of each other so that the fixed two fabric layers 111, 112 can be conveyed in particular as a package or as a fabric layer stack 113.

[0121] In particular, the handling mechanism 120 can convey a fabric layer 111 or the described fabric layers 111, 112 fixed together, for example to the sewing machine 140 or another sewing machine. The effector or the handling mechanism 120 can adapt to the contour of the fabric layers 111, 112, for example by fixing points of the handling mechanism 120 being adjustable at which the fabric layers 111, 112 are fixed. For example, the fixing elements 901 shown in FIG. 9 can be arranged for this purpose in which the individual fixing points are formed.

[0122] The fixing mechanism 130 is arranged completely at the effector 101 in an exemplary embodiment. For example, however, a part of the fixing mechanism 130 can also be arranged at a work table 103 on which, for example, the fabric layers 111, 112 are placed. Correspondingly, the handling mechanism 120 is fastened completely to the effector 101, but a part of the handling mechanism 120 can also be fastened to the work table 103.

[0123] The effector 101 thus forms an end part of the handling robot 100 with, for example, a suction device as a handling mechanism 120 which grips and manipulates a fabric layer 111, 112 or a fabric layer stack 113 which consists of fabric layers 111, 112 which are fastened by the fixing mechanism 130.

[0124] The sewing machine 140 is configured to process the joining regions of a fabric layer 111, 112 and / or to connect at least two fabric layers 111, 112. The sewing machine 140 can be a sewing machine, a welding machine, a stapling machine, a crocheting machine, an automatic gluing machine or further automatic connecting machines for fabric layers 111, 112.

[0125] FIG. 1 shows the handling robot 100 which, by means of a suction device as a handling mechanism 120, places a fabric layer 112 on a work surface 102 of the work table 103. The work surface 102 aligns itself in a horizontal x, y plane. The effector 101 can be moved, for example, along the horizontal plane and in the vertical direction z.

[0126] Next, as illustrated in FIG. 2, a first fabric layer 111 can be placed by means of the suction device as a handling mechanism 120 onto the second fabric layer 112, which is already placed on the work table. The fabric layers 111, 112 are oriented relative to each other such that, for example, the joining regions 114, 115 here, at which the two fabric layers 111, 112 are to be connected, for example by means of a seam, lie one above the other and are oriented.

[0127] In a next step, as illustrated for example in FIG. 3, the fixing device 130 on the effector 101 is activated. In the exemplary illustration, the fixing mechanism 130 comprises a holding needle device 131, which penetrates holding needles 132 through the two fabric layers 111, 112 in order to hold these two to each other in a fabric layer stack 113.

[0128] Subsequently, as illustrated in FIG. 4, the handling mechanism 120 is in turn activated by, for example, a suction cup / suction unit generating negative pressure and thus fastening the fabric layer stack 113 to the effector 101. The effector 101 is subsequently conveyed together with the fabric layer stack 113 to the sewing machine 140, with the result that the joining regions 114, 115 are exactly positioned in the processing region of the sewing machine 140. Subsequently, the sewing machine 140 can process the joining regions 114, 115.

[0129] FIG. 5 shows a schematic illustration of a handling mechanism 120 which holds a fabric layer stack 113 within an effector contour 501. The fixing mechanism 130 or the handling mechanism 120 comprises an effector contour 501 with a fixing surface within the outer joining regions 114, 115, in which fixing surface a fixing force can be transmitted to at least the fabric layers 111, 112.

[0130] The effector contour 501 describes the region on a fabric layer 111, 112 at which the fixing mechanism 130 and / or the handling mechanism 120 exerts a fixing or holding force. The effector contour 501 is defined, for example, by the outline of the fixing surface or by the connecting lines between the individual fixing points at which a holding contact with a held fabric layer 111, 112 is present within the x-y plane. In the illustration in FIG. 5, a plurality of holding needles 132 have been introduced by the holding needle device 131 in order to hold the two fabric layers 111, 112 together. The connecting lines form the effector contour 501 within the fabric layer 111, 112. At the outer edge regions of the fabric layers 111, 112 which lie outside the effector contour 501 which is defined by the fixing points at which the handling mechanism holds the fabric layers 111, 112, the joining regions 114, 115 are formed and the fabric layer 111, 112 can be present untensioned there and project so to speak out of the x-y plane.

[0131] FIG. 6 shows a schematic illustration of a magnet device as a fixing mechanism 130. The magnet device comprises a magnetic element 601. The magnet device can attract the magnetic element 601 in the direction of the effector 101 in such a way that the fabric layers 111, 112, which can be arranged between the effector 101 and the magnetic element 601, can be fixed. The magnetic element 601 can for example form a flat magnetic disk which lies under a lower fabric layer 111, 112 on the work table 103. Further fabric layers 111, 112 can be placed over the lower fabric layers 111, 112. The magnet device at the effector 101 can for example comprise a controllable electromagnet. The effector 101 can thus travel to the fabric layer stack 113 and activate the magnet device so that the magnetic element 601 arranged at the bottom is attracted in the direction of the magnet device or effector 101 and fixes the intermediate fabric layers 111, 112.

[0132] FIG. 7 shows a schematic illustration of an effector 101 with a contact surface 701 according to an exemplary embodiment. The abutment surface 701 is formed within the effector contour 501, at which one of the fabric layers 111, 112 or the fabric layer stack 113 can abut. The abutment surface 701 in particular forms a part of the handling mechanism 120 for fixing one of the fabric layers or the fabric layer stack 113, wherein the abutment surface 701 is configured to hold one of the fabric layers 111, 112 or the fabric layer stack 113 magnetically, based on air pressure, mechanically or electrostatically on the effector 101. The abutment surface 701 allows the fabric layers 111, 112 or the fabric layer stack 113 to be transported in a warp- and fold-free manner and to be deposited later. After the positioning or stacking of the fabric layers 111, 112, the fabric layers can be fixed more easily with the abutment surface 701.

[0133] The work surface 102 comprises a support device 702, which is configured to fix one of the fabric layers 111, 112 or the fabric layer stack 113 on the work surface 102 by means of a support force, in particular by means of pneumatic, mechanical and / or electrostatic support forces. The support device 702 is for example fastened to the worktable 103. The support device 702 can be based on pneumatic, electrostatic or magnetic principles. Thus, for example, a ferromagnetic plate can lie on the work table 103, on which a fabric layer 111, 112 is deposited, which can later serve as magnetic element 601 of the magnet device.

[0134] FIG. 8 shows a schematic illustration of an effector 101 with a handling mechanism 120 and a fixing mechanism 130 according to an exemplary embodiment. For example, the effector 101 can first be placed over a fabric layer stack 113 in order to introduce holding needles 132 into the fabric layers 111, 112 so that the fabric layers 111, 112 are fastened to each other. In a next step, the effector 101 can be placed with the handling mechanism 120, which for example comprises a suction device, over the fabric layer stack 113 in order to hold the latter at the effector 101 and to be transported further to a sewing machine 140.

[0135] FIG. 9 shows a schematic illustration of a worktable 103 with adhesion regions 901 with different static friction, in particular with adjustable static friction. The handling mechanism 120 takes into account the different adhesion regions for aligning fabric layers 111, 112 when positioning the first fabric layer 111, the second fabric layer 112 or the fabric layer stack 113. The worktable 103 can comprise zones of different friction / adhesion. It can thus be advantageous if the lower fabric layer 112 does not slip during the precise placement for the fixing because it has a high friction / adhesion with respect to the work surface (while the upper fabric layer 111 is placed thereon). If both fabric layers 111, 112 are then fixed by means of the fixing mechanism 130, the robot can lift the fabric layers 111, 112 by means of the handling mechanism 120 and reposition them into a region with better sliding capacity for the sewing or the adhesion to the work surface can be switched off.

[0136] The roughness of the work surface 102 of the work table 102 can be adjusted by providing, for example, retractable and extendable bristles 902. The bristles 902 can extend at right angles to the work surface 102 of the work table 103. Additionally or alternatively, bristles 901 can have an angle of less than 90° to the work surface 102 of the work table 103. Thus, a different friction can be adjusted depending on the direction of movement of the fabric layers 111, 112 over the bristles 902. In an exemplary embodiment, a control unit can control the extension of the bristles 902. Furthermore, the angle of the bristles can be adjusted in order to thus adjust the friction 902 and in particular the direction of friction with respect to the fabric layers 111, 112 over the bristles 902.

[0137] FIG. 10 shows a schematic illustration of a handling mechanism 120 with a gripping device according to an exemplary embodiment of the present disclosure. A gripper 1001 of the gripping device is configured such that it encloses the edge of the fabric layer stack 113 and grips the fabric layer stack 113 from above from below, i.e. from the left and from the right side of the fabric layer stack 113.

[0138] FIG. 11 shows a schematic illustration of a handling mechanism 120 with a suction device according to an exemplary embodiment of the present disclosure. The suction device comprises a sucking unit 1101, wherein the suction device is configured to suck air from the first and second fabric layers 111, 112 by means of the sucking unit 1101 in such a way that the first and second fabric layers 111, 112 lying on one another can be fixed to the suction device. Since the fabric layers 111, 112 are permeable to air to a certain degree due to their material characteristic, two or more fabric layers can be fastened in a fabric layer stack 113 by means of suction with a correspondingly adjusted suction power. The suction device comprises, for example, a vacuum pump, which can for example be arranged spaced apart from the effector, for example at the work table 103.

[0139] FIG. 12 shows a schematic illustration of a handling mechanism 120 with an electrostatically charged attraction element 1201 according to an exemplary embodiment of the present disclosure. The electrostatically charged attraction element 1201 can for example be electrostatically charged in order to thus correspondingly fix the fabric material of the fabric layers 111, 112. The electrostatic charging can for example be generated via a correspondingly connected current generating device, which is controlled by the control unit 105.

[0140] FIG. 13 shows a schematic illustration of a handling mechanism 120 with holding needles 1301 according to an exemplary embodiment of the present disclosure. The handling mechanism 120 comprises a holding needle device, which is configured such that a penetration depth and / or a penetration angle of at least one holding needle 1301 is controllable, in particular in real time and / or based on a sensor feedback. An additional form of differentiated gripping by the handling mechanism 120 can represent the depth of a holding needle 1301 and / or the angle of a holding needle 1301 (and in particular relate to a plurality thereof).

[0141] FIG. 14 shows a schematic illustration of an effector 101 with a plurality of different handling mechanisms 120, for example with a suction device 1101 and holding needles 1301 according to an exemplary embodiment of the present disclosure.

[0142] FIG. 15 shows a schematic illustration of a handling mechanism 120 with a gripper 1001, which grips an upper side of a fabric layer, according to an exemplary embodiment of the present disclosure. The gripper 1001 grips a region of a surface of the fabric layer stack 113 in the manner of tongs.

[0143] FIG. 16 shows a schematic illustration of a handling mechanism 120 with a suction surface 1601 according to an exemplary embodiment of the present disclosure. The suction surface 1601 forms an abutment surface 701 as part of the handling mechanism 120, at which one of the fabric layers 111, 112 or the fabric layer stack 113 can abut. The suction surface 1601 comprises a plurality of suction openings 1602.

[0144] FIG. 17, FIG. 18 and FIG. 19 show schematic illustrations of a fixing mechanism 130 with a folding device according to an exemplary embodiment of the present disclosure. The folding device is configured to fold an edge region of a fabric layer 111 in such a manner that the folded edge region forms the first fabric layer 111 which rests on the second fabric layer 112. The folding device comprises a clamping element 1703 in order to clamp the folded first fabric layer 111 and the second fabric layer 112 together.

[0145] The folding device is fastened to the worktable 103 by means of a bearing 1704. A fixed support beam 1702 is arranged at the bearing 1704. Furthermore, the folding device comprises a movable folding beam 1701, which is movably arranged at the bearing 1704. The folding beam 1701 runs parallel to the support beam 1702 and can be pivoted around this support beam 1702. The folding beam 1701 and the support beam 1702 run parallel (and e.g. horizontally) to the work surface 102.

[0146] As illustrated in FIG. 17, a fabric layer 111 is fastened to the effector 101 at a suction surface 1601. Furthermore, a pivotable clamping element 1703 is arranged at the effector 101 or the suction surface 1601 at the effector 101. The clamping element 1703 can be pivoted over an axis of the effector 101 or the suction surface 1601. In an initial position, the folding beam 1701 and the support beam 1702 are spaced apart so that a region of the fabric layer 111 can be positioned between the folding beam 1701 and the support beam 1702.

[0147] Subsequently, as illustrated in FIG. 18, the folding beam 1701 is pivoted around the support beam 1702, wherein the folding beam 1701 continues to remain parallel to the support beam 1702 and carries along a region of the fabric layers 111 and thus folds it around the support beam 1702. Accordingly, as a result, two fabric layers 111, 112 lie one on top of each other. Between the effector 101 and / or the suction surface 1601 and the folding beam 1701, in particular the joining region 115 and / or an edge region of the second fabric layer 112 is present. Subsequently, the clamping element 1703 is pivoted out over the edge of the effector 101 or the suction surface 1601 and clamps the two fabric layers 111, 112 together.

[0148] For this purpose, the effector 101 or the suction surface 1601 comprises a contact region 1705 on which an edge region of the folded second fabric layer 112 lies, with the result that the clamping element 1703 can clamp this edge region and / or can press it against the contact region 1705. The contact region 1705 can comprise a projection at the effector 101 and / or the suction surface 1601 which extends from an edge of the effector 101 and / or the suction surface 1601 and around which the fabric layer 112 lies after the folding. In other words, the projection is arranged between the two fabric layers 111, 112 after the folding.

[0149] Furthermore, the length of the folded second fabric layer 112 can be longer than a distance between an edge of the effector 101 or the suction surface 1601 and the support beam 1702. An end region of the folded second fabric layer 112 is thus folded up and placed against the edge surface. The clamping element 1703 subsequently pivots in the direction of the edge surface and clamps the folded-up part of the second fabric layer 112.

[0150] As illustrated in FIG. 19, the effector 101 can pull out the fabric layers 111, 112 horizontally in the extension direction of the folding beam 1701 and the support beam 1702, wherein the fabric layers 111, 112 are held in the folded position by means of the clamping element 1703. The effector 101 can now be pivoted into a horizontal position, with the result that the fabric layers 111, 112 can rest in a flat manner on the worktable 103. The clamping element 1703 continues to clamp the fabric layers 111, 112 together. The joining regions 114, 115 at which the sewing machine 140 can, for example, place a seam are illustrated at the free end.

[0151] FIG. 20 shows a schematic illustration of the folding device, which can be arranged on a worktable 103. The folding beam 1701 and the support beam 1702 are fastened at one end to the bearing 1704. Free ends are provided at the opposite ends of the folding beam 1701 and of the support beam 1702. After the fabric layers 111, 112 have been folded by means of the folding beam 1701, the effector 101 can be moved horizontally, with the result that the folding beam 1701 is moved out of the pocket formed between fabric layers 111, 112.

[0152] FIG. 21 shows a schematic illustration of a fabric layer 111 with a protrusion 2101 outside an effector contour 501, according to an exemplary embodiment. The fabric layer 111 has, for example, the form of an outer skirt. The second fabric layer 112 is arranged below the fabric layer 111. The first fabric layer 111 comprises a plurality of fixing regions 2100. The fixing points of the handling mechanism 120 and / or of the fixing mechanism 130 grip at the fixing regions 2100. At the edge of the inner effector contour 501, in particular fixing points of the handling mechanism 120 are provided in order to raise the first fabric layer 111 as far as possible tensionized in a fold-free manner. Fixing elements for the fixing mechanism 130 can be provided in the interior of the effector contour 501, at which fixing elements the fixing mechanism 130 fixes both fabric layers 111, 112 together. For example, corresponding holding needles 132 of the holding needle device 131 can be introduced at the fixing elements of the fixing mechanism 130 in order to fasten both fabric layers 111, 112 to each other.

[0153] The effector contour 501 is smaller than the outer contour of the fabric layers 111, 112, with the result that the projection 2101 is formed in this region between the outer contour of the fabric layers 111, 112 and the effector contour 501, in which projection in particular the joining region 114 is formed. The effector can thus convey the fabric layers 111, 112 to a sewing machine 140, with the result that the latter places a corresponding seam in the joining region 114.

[0154] FIG. 22, FIG. 23 and FIG. 24 show schematic illustrations of a handling mechanism 120 with holding needles 1301 according to an exemplary embodiment.

[0155] Holding needles 1301 are arranged at a control surface 2201 of the handling mechanism 120, wherein a surface shape of the control surface 2201 is adjustable such that in a first configuration of the surface shape the holding needles 1301 are oriented parallel to each other (see FIG. 22) in order to penetrate into or move out of at least one fabric layer 111, 112, and in a second configuration of the surface shape the holding needles 1301 are not oriented parallel to each other (see FIG. 23 or FIG. 24) in order to fix them in at least one fabric layer 111, 112.

[0156] As a result of the bending of the control surface, the holding needles 1301 spread apart and fix the two fabric layers 111, 112. In the case of a bending back of the control surface, for example a uniform movement or abruptly by means of a clicking back, the holding needles 1301, which are in particular again oriented parallel to each other, are released again from the fabric layers 111, 112. The surface shape of the control surface 2201 can be deformable and in particular pre-tensionable by means of mechanical, pneumatic or hydraulic elements. The control surface 2201 can be configured to be elastically deformable, so that it can be pre-tensioned and is automatically deformed back without an external restoring force into a starting position, for example by the holding needles 1301 running parallel or by the holding needles 1301 having an angle to each other.

[0157] In the exemplary embodiment shown, a control chamber 2202 is formed between the effector 101 and the control surface 2201. The control chamber can be supplied with air (or a gas, in a hydraulic embodiment a hydraulic liquid) via an air line 2203. For example, an overpressure can be generated in the control chamber 2202, as a result of which the control surface 2201 deforms outwards and the holding needles 1301 are correspondingly spread apart (see FIG. 23). Alternatively, air can also be drawn out of the control chamber 2202, so that a negative pressure is generated and the control surface 2201 deforms inwards (see FIG. 24). The holding needles 1301 are thus pushed together at their tips. A corresponding fabric layer 111, 112 can be held by means of the holding needles 1301 which are spread apart or pushed together.

[0158] FIG. 25 shows a schematic illustration of a positioning of a third fabric layer 2501 on two already sewn fabric layers 111, 112 according to a further exemplary embodiment. A first fabric layer 111 and a second fabric layer 112 lie partially one on top of the other on a work table 103 and have in particular already been sewn together with a seam 2503 by the method according to the disclosure. The handling mechanism 120 is equipped with a sucking unit 1101 which already holds a further third fabric layer 2501 within the effector contour 501. The edge regions of the third fabric layer 2501 are freely accessible and form a third joining region 2502. The effector 101 is controlled by means of the robot arm 104, with the result that the third fabric layer 2501 is placed over the first fabric layer 111. For example, the third joining region 2502 can thus lie over the seam 2503 and thus over the respective first and second joining regions 114, 115. Subsequently, the first fabric layer 111, the second fabric layer 112 and the third fabric layer 2501 can be sewn to each other. For example, the second fabric layer 112 can represent a tag or label and can thus be sewn into a kind of seam.

[0159] In addition, it should be noted that “comprising” does not exclude any other elements or steps and “a” or “an” does not exclude a plurality. Furthermore, it should be pointed out that features or steps which have been described with reference to one of the above exemplary embodiments can also be used in combination with other features or steps of other exemplary embodiments described above. Reference signs in the claims are not to be regarded as a restriction.List of reference signs:100 Handling robot101 Effector102 Work surface103 Worktable104 Robot arm105 Control unit111 First fabric part / fabric layer112 Second fabric part / fabric layer113 Fabric layer stack114 First joining region115 Further joining region120 Handling mechanism130 Fixing mechanism131 Holding needle device132 Holding needles140 Sewing machine501 Effector contour601 Magnetic element701 Effector contact surface702 Support device901 Adhesion region902 Bristles1001 Gripper1101 Sucking unit1201 Electrostatic attraction element1301 Holding needles1601 Suction surface1602 Suction opening1701 Folding beam1702 Support beam1703 Clamping element1704 Bearing at the worktable1705 Contact region2100 Fixing region2101 Projection2201 Control surface2202 Control chamber2203 Air line2501 Third fabric layer2502 Third joining region2503 Seam

Examples

Embodiment Construction

[0116]Identical or similar components in different figures are provided with identical reference numerals. The illustrations in the figures are schematic.

[0117]FIG. 1, FIG. 2, FIG. 3 and FIG. 4 show schematic illustrations of a method for robot-assisted sewing of fabric layers 111, 112 for clothing. The method comprises gripping a first fabric layer 111 or second fabric layer 112 by a handling mechanism 120 of a handling robot 100 with an effector 101 for handling fabric layers 111, 112 (see FIG. 1). The first fabric layer 111 is positioned above a second fabric layer 112 which rests on a worktable 103 (see FIG. 2) and the first fabric layer 111 is fixed with the second fabric layer 112 to form a fabric layer stack 113 by means of a fixing mechanism 130 which is arranged at least partially at the effector 101 in such a way that a joining region 114 of the first fabric layer 111 rests on a further joining region 115 of the second fabric layer 112 (see FIG. 3). Furthermore, the fabric...

[0001] This application is a national US phase of PCT / EP2024 / 065623 which claims the benefit of the filing date of the German Patent Application No. 10 2023 114 965.2 filed 7 Jun. 2023, the disclosure of which is hereby incorporated herein by reference.TECHNICAL FIELD

[0002] The present disclosure relates to a method and a system for robot-assisted sewing of fabric layers.BACKGROUND OF THE DISCLOSURE

[0003] In the technical field of textile processing, it is an aim to increase the degree of automation in order to reduce personnel costs and correspondingly production costs.

[0004] A textile processing system which is designed, for example, for automated sewing requires a handling mechanism in order to singulate the fabric from a stack and to feed it in sufficient proximity to a sewing system (or a sewing machine) after manipulation. For this purpose, robots with an effector on which corresponding gripping mechanisms for gripping the textile piece are arranged are used. However, fabric parts which represent a piece of clothing have different sizes and can have different properties (thickness, air permeability, stiffness, etc.) both among one another and within the same piece.

[0005] During the sewing with a sewing machine, two fabric layers placed one above the other are moved relative to the sewing machine in order to produce a seam. The fabric layers can be moved by the sewing machine itself or by means of a special guide unit which guides the fabric layers relative to a sewing machine. Before and after the sewing operation, the fabric layers must be fed and removed with further handling elements. Therefore, a longer set-up time must be accepted before the sewing operation and after the sewing operation until a sewing operation can start.SUMMARY OF THE DISCLOSURE

[0006] There may be a need to increase the efficiency of an automatic sewing operation.

[0007] This need is met with a method and a system for robot-assisted sewing of fabric layers according to the subject matter of the independent patent claims.

[0008] According to a first aspect of the present disclosure, a method for robot-assisted sewing of fabric layers for clothing is described. The method comprises gripping a first fabric layer by a handling mechanism of a handling robot with an effector for handling fabric layers. The first fabric layer is positioned above a second fabric layer which rests on a worktable and the first fabric layer is fixed with the second fabric layer to form a fabric layer stack by means of a fixing mechanism which is arranged at least partially at the effector in such a way that a joining region of the first fabric layer rests on a further joining region of the second fabric layer. Furthermore, the fabric layer stack is fed to a sewing machine by means of the handling mechanism, wherein the joining regions are freely accessible for the sewing machine. The joining regions are sewn, wherein during the sewing the handling mechanism guides the fabric layer stack relative to the sewing machine. The sewn fabric layer stack is fed by means of the handling mechanism from the sewing machine to a depositing location.

[0009] According to a further aspect, a system for robot-assisted sewing of fabric layers for clothing is described. The system comprises a handling robot with an effector, which comprises a handling mechanism for handling fabric layers, wherein the handling mechanism is configured to grip a first fabric layer. The handling mechanism is configured to position the first fabric layer above a second fabric layer which rests on a worktable.

[0010] The system furthermore comprises a fixing mechanism which is arranged at least partially at the effector, wherein the fixing mechanism is configured to fix the first fabric layer and the second fabric layer to one another to form a fabric layer stack in such a way that a joining region of the first fabric layer rests on a further joining region of the second fabric layer. Furthermore, the system comprises a sewing machine. The handling mechanism is configured to feed the fabric layer stack to the sewing machine, wherein the joining regions are freely accessible for the sewing machine. The sewing machine is configured to sew the joining regions, wherein the handling mechanism is configured to guide the fabric layer stack relative to the sewing machine during the sewing.

[0011] The handling mechanism is configured to convey the sewn fabric layer stack from the sewing machine to a depositing location.

[0012] The handling robot comprises the effector on which the corresponding handling mechanism is, in particular exchangeably, attached. The handling robot is fastened with a stationary robot base on the floor or on the worktable in order to introduce corresponding forces into the corresponding system. Alternatively, the handling robot is also configurable such that the robot base is configured to be movable along the floor. A robot arm can be arranged between the effector and the robot base, which robot arm comprises, for example, one or more joints in order thus to control the effector into a desired position.

[0013] The handling robot is a programmable multi-purpose handling device for moving material, workpieces, tools or special devices. In particular, the handling robot is configured to handle or manipulate the fabric layers and to move and position them accordingly. In other words, the handling robot enables a machine-controlled position change possibility in more than one axis and / or along a translational position change of the fabric layers.

[0014] The term fabric layer denotes the possible textiles or textile parts of a textile product, in particular a piece of clothing. The term fabric layer includes different knitted forms, in particular woven and non-woven fabrics. The left / left side of a fabric layer denotes the inner side (i.e. the fabric underside, fabric inner side or the “not beautiful side” of a fabric layer). In the case of a piece of clothing, the left side corresponds to the non-visible side of the fabric layer. The “beautiful side” of a fabric or fabric layer is used as the right / right side of a fabric layer (e.g. the fabric upper side, visible side, fabric outer side). In the case of a piece of clothing, the right side corresponds to the visible side of the fabric or the fabric layer (e.g. the outer side of a T-shirt). Furthermore, a fabric part can consist of a plurality of fabric layers. For example, a fabric part (such as a piece of clothing) can be folded several times and can rest on a worktable as a fabric layer stack with a plurality of fabric layers. Alternatively, the fabric layers can each represent separate fabric parts which form a fabric layer stack one above the other.

[0015] A joining region of a fabric layer describes a region which is to be processed using a sewing machine. For example, the joining region can be that region of a fabric layer at which a seam or a seam can run. In particular, joining regions of two fabric layers lying one on top of the other are laid one above the other so that they can be connected by means of the sewing machine (for example by means of sewing or welding).

[0016] The controllable handling mechanism and the fixing mechanism are arranged at the effector. The fixing mechanism is configured to fasten at least two fabric layers which in particular lie one on top of each other so that the fixed two fabric layers can be conveyed in particular as a package or as a fabric layer stack.

[0017] In particular, the handling mechanism can convey a fabric layer or the described fabric layers fixed together, for example to the sewing machine. The effector or the handling mechanism can adapt to the contour of the fabric layers, for example by fixing points of the handling mechanism being adjustable at which the fabric layer is fixed. For example, the fixing elements described below can be arranged for this purpose in which the individual fixing points are formed. The handling mechanism covers in particular the contour-relevant points of a contour of the fabric layer, wherein preferably an edge of the fabric layers remains free as a joining region and is not covered by the handling mechanism. The region of the fabric layers which is covered by the effector or the handling mechanism for fixing the fabric layers is referred to below as the effector contour.

[0018] The fixing mechanism is arranged completely at the effector in an exemplary embodiment. For example, however, a part of the fixing mechanism can also be arranged at a worktable on which, for example, the fabric layers are placed. Correspondingly, the handling mechanism is fastened completely to the effector, but a part of the handling mechanism can also be fastened to the worktable. In exemplary embodiments, functional elements of the fixing mechanism can form elements of the handling mechanism and vice versa. For example, a holding needle device or suction device of the fixing mechanism can fix a plurality of fabric layers, but can also hold the fabric layer stack thus formed at the effector, with the result that the function of the handling mechanism is likewise fulfilled.

[0019] The effector thus forms an end part of the handling robot with, for example, grippers as a handling mechanism which grip and manipulate a fabric layer (for example a planar, unprocessed fabric layer or an entire piece of clothing as a fabric layer) or a fabric layer stack which consists of fabric layers which are fastened by the fixing mechanism.

[0020] For example, the sewing machine can connect two fabric layers to each other, with the result that a seam is produced. For example, the seam describes the connection of two fabric layers by means of a thread or yarn, wherein at least the one material substantially represents a fabric, a non-woven fabric or a woven fabric.

[0021] For automatic packaging of textile products, the connection of two fabric layers is a basic requirement for many products, in particular in the production of pieces of clothing. For this purpose, according to the disclosure, two fabric layers can be exactly placed by means of the handling mechanism, with the result that the joining regions lie exactly one on top of the other and are fixed by means of the fixing mechanism. In order that a plurality of fabric pieces can be precisely stacked one on top of the other with the effector and then fixed for further processing, the effector according to the disclosure allows a depositing of a first fabric layer on a surface of a worktable, a precicely aligning and depositing a further fabric layer on the fabric layers already lying on the worktable, and a fixing of the two fabric layers by means of the fixing mechanism. By means of the handling mechanism, a “repositioning of a fabric layer” and “stacking” can be enabled.

[0022] An effector / gripper system according to the disclosure equipped in this way is capable of stacking fabric layers exactly one on top of each other, with the result that these two fabric layers can then be joined. However, a fabric part can thus also be folded with the folding device (German: Umlegevorrichtung) described below, with the result that two fabric layers are produced therefrom, which can then be fixed and further processed (e.g. fold seam). In order to fix the two fabric layers on top of each other, preparing measures can at best already be performed with the system before the placement, these can encompass folding (see the folding device described below), or adding (of an adhesive), introducing (auxiliary material for ultrasonic welding), etc., which is enabled with the fixing mechanism. Such a preparing action is enabled according to the disclosure with an additional device or fixing mechanism which is installed either at the effector or at the worktable.

[0023] With the method according to the disclosure and the system, the fabric layers can be held at the same effector by means of the handling mechanism during the entire handling process before the sewing and after the sewing. Thus, no changeover (German: Umrüsten) between a feeding device before the sewing and a device after the sewing is necessary. Since the fabric layers are held together by means of the fixing mechanism before and while the sewing, and the handling mechanism fastens the fabric layers to the effector before, during and after the sewing, no further conveying unit is necessary, with the result that a more efficient sewing process can be provided.

[0024] According to a further exemplary embodiment of the method, the handling mechanism singulates the second fabric layer from a plurality of fabric layers and deposits it in a flat manner on a work surface of the worktable, so that subsequently the first fabric layer is positioned above the second fabric layer. In other words, a singulation of a fabric layer from a fabric layer stack is thus carried out and subsequently it is placed in a flat manner on the work surface. Subsequently, a second fabric part is gripped with the handling mechanism and placed on the second fabric layer with a defined overlap, in particular of the joining regions. This has the advantage that the effector can place the second fabric layer on a layer whose location is already precisely known (e.g. from a previous placing step).

[0025] According to a further exemplary embodiment, the first fabric layer and the second fabric layer form regions of a fabric part, wherein the positioning of the first fabric layer above the second fabric layer is carried out by folding the fabric part, in particular by means of a folding device which is configured to fold an edge region of the fabric part in such a manner that the folded edge region forms the first fabric layer which rests on the second fabric layer. In particular, a projection of a fabric layer which projects beyond the effector or the effector contour is folded by means of a seam folder (folding device). This has the advantage that the fabric part only has to be gripped once by means of the handling mechanism (e.g. during the singulation) and thus a higher positional reliability prevails, which contributes to a reduced error rate and reduces the tendency to folds. The folding device is configured to fold an edge region of a fabric layer in such a manner that the folded edge region forms the first fabric layer which rests on the second fabric layer. The folding device is arranged in particular at the work table. The folding device comprises a clamping device which is provided at the effector or at the work table and which is configured in provided at the effector in order to clamp the folded first fabric layer and the second fabric layer together.

[0026] According to a further exemplary embodiment, the first fabric layer is fixed with the second fabric layer by means of temporary fixing elements, in particular holding needles, which are removed during sewing, in particular taking into account the sewing progress, or after sewing.

[0027] According to a further exemplary embodiment, a work surface of the worktable comprises adhesion regions with different static friction. The handling mechanism takes into account the different adhesion regions for aligning the first fabric layer, the second fabric layer or the fabric layer stack when positioning the first fabric layer, the second fabric layer or the fabric layer stack. The adhesion of the adhesion regions can in particular be controllable in an exemplary embodiment. The worktable can comprise zones of different friction / adhesion. This difference can be permanent or switchable / regulatable and thus temporary. It can thus be advantageous if the lower fabric layer does not slip during the precise placement for the fixing because it has a high friction / adhesion with respect to the work surface (while the upper fabric layer is placed thereon). If both layers are then fixed by means of the fixing mechanism, the robot can lift the fabric layers by means of the handling mechanism and reposition them into a region with better sliding capacity for the sewing or the adhesion to the work surface can be switched off.

[0028] According to a further exemplary embodiment, the sewing machine comprises a sewing foot with a sewing foot length in the conveying direction of the fabric layers to be sewn, wherein a sewing foot length in the conveying direction is larger than 20 mm, larger than 40 mm, or larger than 60 mm. Such a long sewing foot additionally prevents a rolling up of the fabric layers to be sewn and leads to the fabric layers being present in a flat and fold-free manner for sewing on the sewing machine and sliding into the sewing region of the sewing machine. The sewing foot smooths the fabric layers during the sewing. At the same time, the sewing foot generates a pressure on the underlying fabric layers. The fabric layers are fixed between the sewing foot and a lower part of the sewing machine, e.g. a transport element for the fabric layers, lifted and transported further stitch by stitch. In addition, a negative pressure region can be provided at the work table in the conveying direction in front of the sewing foot of the sewing machine in order to smooth the fabric layers in front of the sewing machine.

[0029] In particular, the sewing region on which the fabric layers rest during the sewing has a smoother surface of the work table than a rougher surface of the work table at a region in which the first fabric layer is positioned on the second fabric layer.

[0030] According to a further exemplary embodiment, the handling mechanism moves the fabric layer stack over the adhesion regions such that the position of the lower second fabric layer is adjusted to the first upper fabric layer due to the static friction to the adhesion region.

[0031] In an exemplary embodiment, the roughness of a surface of the work table can be adjusted by providing, for example, retractable and extendable bristles (German: Borsten). The bristles can extend at right angles to the surface of the work table. In addition or alternatively, bristles can have an angle of less than 90° to the surface of the work table. Thus, a different friction can be adjusted depending on the direction of movement of the fabric layers over the bristles. In an exemplary embodiment, a control unit can control the extension (German: Ausfahren) of the bristles. Furthermore, in a further exemplary embodiment, the angle of the bristles can be adjusted in order to thus adjust the friction and in particular the direction of friction with respect to the fabric layers via the bristles.

[0032] For example, oblique receiving bores can be drilled or punched into the surface of the work table, which can receive correspondingly oblique bristles (alternatively, for example, obliquely positioned tips or microneedles can be used). Alternatively, the bristles can be correspondingly adhesively bonded to a surface or corresponding bristles can be produced from plastic by means of a injection molding method. Very fine structures can be produced by means of brushing, grinding, engraving or etching of the surface. Moving or flexing fabric layers over such a surface leads to a preferential movement in one of the coordinate directions along the work table (X, Y), which can be used for tensioning or smoothing fabric layers and / or for reducing fold formation. This effect can also be achieved with other manufacturing techniques. For example, a grating device (German: Raffeleinrichtung) with elastic and / or movable lamellae can be used on the surface of the work table, which lamellae, however, consist of softer materials and the fabric layer is not moved “against the line” (German: “gegen den Strich”), but only leads to smoothing of the fabric with slight pressure of the fabric layer on the gathering device.

[0033] According to a further exemplary embodiment, during the sewing the handling mechanism moves the fabric layer stack with a first feed motion relative to the sewing machine, wherein the sewing machine moves the fabric layer stack with a second feed motion. The handling mechanism in particular controls the first feed motion differently to the second feed motion of the sewing machine. It has proven advantageous to control the feed motion of the effector or of the handling mechanism (which guides the fabric layers) differently to the feed motion of the sewing machine, in particular during the sewing process. Thus, for example, a certain tension can thereby be adjusted for the sewing between the first and the second fabric layer or a quilling formation (German: Ruschenbildung) (that is to say a fabric layer forms loops on the other fabric layer, which remains fold-free and tensioned, or one fabric layer is tensioned or stretched in relation to the other) can be supported. Moreover, distance and movement differences between the handling robot and the sewing machine can thus be adapted, in particular with a time delay.

[0034] According to a further exemplary embodiment, after the step of sewing the method comprises gripping a third fabric layer by the handling mechanism. Furthermore, the third fabric layer is positioned above the sewn first and second fabric layers which rest on a worktable. The third fabric layer is fixed with the sewn first and second fabric layers to form a fabric layer stack by means of the fixing mechanism in such a way that a further joining region of the third fabric layer rests on a further joining region of the first and / or second fabric layer.

[0035] Subsequently, this fabric layer stack is fed to the sewing machine by means of the handling mechanism and the further joining regions are sewn, wherein during the sewing the handling mechanism guides the fabric layer stack relative to the sewing machine. Three layers can thus be sewn to each other, e.g. when sewing a label into a seam. For example, first a label is sewn as a first fabric layer on a second fabric layer, only then the third fabric layer is placed and the step of sewing is repeated. This allows a more precise label placement and reduces slip problems with respect to fixing of three fabric layers.

[0036] According to a further exemplary embodiment, the fixing mechanism fixes the first and second fabric layers along at least one (continuously running) fixing region and / or along a plurality of spaced-apart fixing regions.

[0037] According to a further exemplary embodiment, the fixing regions have an area of less than 1 cm2, in particular less than 20 mm2, in particular less than 8 mm2. Additionally or alternatively, the fixing regions are in particular spaced apart by more than 2 cm, in particular by more than 3 cm or by more than 4 cm. Thus, a good fixing between two fabric layers can be achieved without a nonstop continuous temporary fixing path having to be produced with the fixing mechanism.

[0038] According to a further exemplary embodiment, during or after sewing, at least one of the fixing regions is separated, wherein the fixing region is in particular separated with a separating speed which is coordinated with the feed motion during the sewing with the sewing machine and substantially coincides therewith. The fixing regions are at least partially removed again since they possibly lead to a hardening / stiffening of the fabric layers. Thus, for example, this fixing can take place in a region which is cut off again during or after the sewing operation. For a fixing being present as long as possible, this cutting off can also take place incrementally depending on the sewing progress.

[0039] According to an exemplary embodiment, the work surface of the work table is movably mounted and moved, wherein in particular the movement of the work surface takes place synchronously or in coordination with the movement of the effector. The movement of the work surface takes place in particular during the sewing, wherein the work table comprises in particular a conveyor belt as work surface for conveying at least one fabric layer deposited thereon relative to the sewing machine. In an exemplary embodiment, in particular the movement of the work surface, the handling mechanism and the feed motion of the sewing machine are synchronized (in particular by means of the control unit).

[0040] Thus, a more exact control during the sewing and accordingly a sewing quality (in particular with only weak fixing of the two fabric layers) can be achieved by bilateral transport, i.e. by moving the work surface from below and the movement of the handling mechanism from above. Thus, the work surface can be movably mounted on the work table or the entire work table can be moved. This can be achieved, for example, in that the work surface consists of a conveyor belt. The two fabric layers are precisely positioned and stacked thereon and then pressed on with the effector. If this is implemented with the relevant projection outside the effector contour according to the disclosure, the conveyor belt can move past the sewing machine and at the same time the effector can support the movement synchronously from above. The effort for more complex fixings can thus be reduced and it is nevertheless ensured that no slip of the two fabric layers occurs. The work surface can additionally be equipped with an increased frictional resistance (e.g. ‘no slip’ surface). This embodiment variant is advantageous if the processed fabric comprises a strongly adhering surface or decoration (e.g. rubber covering). Without this displacement support, there can be the risk that the adhesion on the sliding surface during the sewing process is stronger than the fixing, which can lead to warping or a poor seam quality.

[0041] According to a further exemplary embodiment, the handling mechanism comprises an effector contour, wherein one of the fabric layers or the fabric layer stack can be fastened within the effector contour. The effector contour is smaller than an outer contour of the fabric layer or the fabric layer stack. The handling mechanism is configured such that the joining regions of the fabric layers form a projection with respect to the effector contour by more than 0.5 cm, in particular by more than 1 cm, further in particular by more than 2 cm or by more than 3 cm.

[0042] The effector contour describes the region on a fabric layer at which the fixing mechanism and / or the handling mechanism exerts a fixing force or holding force. The effector contour is defined, for example, by the border of the fixing surface or by the connecting lines between the individual fixing points at which a holding contact with a held fabric layer is present within the x-y plane. The connecting lines form an effector contour within the fabric layer. In the inner holding region, the fabric layer can be spanned and thus defines the x-y plane. At the outer edge regions of the fabric layers which lie outside the effector contour which is defined by the fixing points, the joining regions are formed and the fabric layer can be present untensioned there and project so to speak out of the x-y plane.

[0043] As a result of the fabric projection thus produced, a subsequent sewing is facilitated since the sewing machine reaches the joining regions more easily. This projection can then be placed on at least one other free fabric region or joining region of the further fabric layer. Alternatively, the projection can be manipulated such that it is folded (e.g. for a seam) and thus form the first fabric layer and the second fabric layer from a fabric part.

[0044] According to a further exemplary embodiment, the handling mechanism introduces holding needles with a predetermined penetration depth and / or a predetermined penetration angle into the first fabric layer or the fabric layer stack by a holding needle device for fastening to the effector. The predetermined penetration depth and / or the predetermined penetration angle can be determined in particular in real time and / or based on a sensor feedback. The holding needles can in particular have a diameter of less than 1300 micrometers, less than 900 micrometers, in particular less than 550 micrometers, further in particular less than 250 micrometers. Thus, for example, a holding needle can be inserted into the fabric part during transport at a shallow angle or not so deep, while after positioning on another fabric part a steeper angle or a larger penetration depth is used to fix both parts.

[0045] By means of the holding needle device, either from the effector side, from the worktable side or from an auxiliary system (e.g. auxiliary plate, needle band), one or more needle-like pins or holding needles can be driven from a magazine into or through the fabric layers in order to fasten them to each other. The holding needle device comprises in particular a feeding device, for example a holding needle magazine, which is configured to feed holding needles for the holding needle device.

[0046] According to a further exemplary embodiment, at least one of the fabric layers is fixed at the work surface by means of a hold-down device on the work table. The hold-down device is configured to selectively fix at least one of the fabric layers at the work table, in particular by means of pneumatic, mechanical, magnetic and / or electrostatic holding forces. The hold-down device can press with a force against the work table / the work surface, which leads to a fixing of the two intermediate fabric layers. Alternatively, the effector can also allow compressed air to flow in between its underside and the fabric layers. This is in particular helpful when the effector has to reposition itself so that it can quickly overcome the adhesive forces between the effector and the first fabric layer.

[0047] The hold-down device is in particular configured to fix the fabric layers until the fixing mechanism takes over the fixing of the two fabric layers. Furthermore, for example, a ferromagnetic support plate can lie on the work table, on which a fabric part is deposited. After a fabric layer of this fabric part has been folded or after a further fabric layer has been placed, the effector can attract the support plate by means of a magnet (in particular an electromagnet) and thus fix the fabric layers in between. Alternatively, an electrostatic holding mechanism can be used both on the worktable side and on the effector side. This helps in particular with the exact placement of two fabric layers one above the other. After the placement, the effector can then reinforce the fixing in such a way that two fabric layers are held securely and a hold-down device installed in the table can be switched off.

[0048] The work surface is in particular embedded in the work table and the work surface is in particular configured as a work plate with a thickness of less than 1 cm, in particular less than 5 mm or less than 3 mm, wherein the fabric layer stack is in particular deposited on the work surface such that the fabric layer stack forms a protrusion with respect to at least a part of the work surface.

[0049] The work surface can either be a fixedly mounted work table or a movable auxiliary plate (work surface), which can be moved at least in one coordinate direction. Alternatively, this auxiliary plate can also be temporarily connected to the effector and thus move simultaneously with the effector. In particular, the work surface can be partially integrated into the work table and form a surface without substantial height differences in at least one direction (and, for example, be displaceable in another direction). The work surface can also be designed to be relatively thin (i.e. technically speaking may be “of small height” in the z-direction). It is especially advantageous if the fabric stack forms a projection at least on a part of the work surface, since in this way the fabric stack including the work surface can be guided to directly pass next to the sewing system.

[0050] According to a further exemplary embodiment, fabric layer data relating in particular to fabric layer material and / or fabric layer geometry are determined. Additionally or alternatively, processing data, in particular left / right position, alignment, unfolding and / or production quality of one of the fabric layers or of the fabric layer stack are determined. Additionally or alternatively, a positioning, placement, fixing during the sewing and / or the sewing quality is determined. The collected data are evaluated for determining the quality of the sewn fabric layers. In particular, the data can be collected in a data processing unit. A control unit, which is coupled to the data processing unit, can analyze the corresponding data and initiate a corresponding control of the sewing machine or of the handling robot. In this way, a change in the reliability can be detected and communicated to a higher-level system. Thereby, for example, preventive maintenance or an adaptation of the handling parameters can be initiated. For this purpose, the system can also receive information from the sewing machine.

[0051] According to a further exemplary embodiment, the step of fixing comprises a feeding of adhesive for a temporary gluing together of the first fabric layer and the second fabric layer (in particular by means of the fixing mechanism). The adhesive can in particular contain a water-soluble polymer, in particular polyethylene glycol and / or polyvinyl alcohol, sodium thiosulfate pentahydrate, sodium acetate trihydrate, ammonium alum dodecahydrate, ureas and / or eutectic salt mixtures.

[0052] An adhesive device as a fixing mechanism for temporarily fixing the fabric layers can for example comprise an adhesive, which can be thermally activated (hot-melt adhesive principle) and then washed out during the first wash cycle. For this purpose, for example, water-soluble polymers with a relatively moderate melting point are used. Thus for example PEG (polyethylene glycol). For example, a water-soluble polymer with an increased melting temperature, for example around the 200 degrees Celsius, can form PVOH (polyvinyl alcohol) with a suitable degree of hydrolysis. Furthermore, low-melting salts, such as sodium thiosulfate pentahydrate (melting point or glass transition temperature FP 45-50 degrees Celsius) or sodium acetate trihydrate (melting point FP for example 60 degrees Celsius) or ammonium alum dodecahydrate (melting point FP for example 120 degrees Celsius). Here, the cooling and bonding is a phase transformation, which is strongly promoted by the fine fabric / fibre structure. These products are also relatively unproblematic with respect to toxicity and disposal / wash water.

[0053] The adhesive can in particular comprise a pressure-activated adhesive, a hot glue and / or a two-component adhesive, in particular that the adhesive can be removed again during and / or after a further processing step, in particular can be separated together with a material part of the first fabric layer, the second fabric layer and / or the fabric layer stack. In a further exemplary embodiment, a fast-reacting (for example pressure-activated) adhesive is used for in particular temporary fixing. One of the possible embodiments is an encapsulated superglue (German: Sekundenkleber), characterized in that the capsule breaks open under pressure. The capsule is for example composed of a stiff brittle material, such as for example glass, and is very small (capsule diameter in the micrometer range). The administration can be both as a powder of beads and also further incorporated into adhesive dots or adhesive tapes. The processing can be dry or in a conveying fluid (which supplements the superglue or alternatively is the second phase in the case of a quickly curing two-component adhesive [first phase within the capsules]). The adhesive is activated by pressure (by the effector or an additional equipment mounted on the table), fastens the two fabric layers very quickly and thus makes the desired fixing. If this takes place in the region of a section after the subsequent joining, the pollution, the “can no longer be removed” and the rigidity of this process are also not disadvantageous. Alternatively, this can also be realized with a hot glue.

[0054] Furthermore, PVOH adhesive with a low water content, i.e. liquid to low-melting, can be used as the adhesive. In addition, a urea melt with a melting point FP of for example 133 degrees Celsius can be used. In addition, eutectic salt mixtures or substance mixtures can be used as the adhesive.

[0055] In particular in the case of water-soluble polymers, good adhesive properties have been achieved. Thus for example with the product Kollisolv PEG 3350 from BASF, which melts at only 50 degrees and is readily water-soluble. In particular, the adhesives described above are also non-toxic and are permitted for medical applications, which does not give rise to any discussions with respect to human contact in clothes before washing. In addition, the adhesive bonding can take place in a region of the fabric layers which is separated in the later processing.

[0056] According to a further exemplary embodiment, during sewing a seam end is detected (for example by means of optical sensors), wherein during sewing at the seam end the feed motion of the handling device and / or of the sewing machine is changed at the seam end in order to vary a tension of the fabric layers between the sewing machine and the effector in strength and / or direction. This ensures that for example a special action can be carried out at the seam end, such as, for example, an end knot, a sealing of the seam end or a certain seam length, with the result that the thread can be cut off at the end.

[0057] According to a further exemplary embodiment, after sewing a thread with a predetermined thread length is cut off after one end of the seam, wherein the handling mechanism moves the fabric layer stack relative to a thread cutting device such that the thread length is adjustable. For example, at the end of a seam, after the last stitch has been put through, an extended thread section can be generated by means of a quick movement of the handling mechanism away from the sewing machine. In other words, for example a displacement movement can be provided for repositioning the fabric layers by means of the handling mechanism or the effector, which either guides the thread to a thread cutter (or vice versa) or it can also be easy to pull the free thread through the sewing system, with the result that a defined thread length is achieved at the end of the seam.

[0058] According to a further exemplary embodiment, a heating device for heating the fabric layers and / or a moistening device for moistening the fabric layers is arranged at the work table in order to smooth, in particular iron, at least one of the fabric layers and / or the fabric layer stack. Additionally or alternatively, to carry out the smoothing action, the effector can comprise a smoothing plate, in particular a heatable smoothing plate, and can be configured such that smoothing can be carried out by pressing the smoothing plate onto the fabric layer.

[0059] According to a further exemplary embodiment, a further sewing device is arranged at the work table so that during or after sewing the joining regions the further sewing device sews further joining regions of the first and second fabric layers. The sewing device and the further sewing device in particular form different sewing seams, in particular an overlock seam and a coverstitch seam, in the joining regions. It is efficient if the handling robot carries out more than one activity or operates a plurality of sewing devices by means of a held fabric layer stack on the basis of position knowledge. For this reason, it is advantageous if more than only one sewing system is available within the work region of the handling robot. On the one hand, different tasks (sewing two fabrics together and sewing a seam) can thus be carried out without making large interruptions necessary because of a resumption of the fabric layers, on the other hand, the thread breakage of a machine can thus also be compensated for by the use of an alternative machine. In particular, it can be advantageous if these sewing systems are different because in this way different tasks can be achieved without re-gripping of the effector. For example, if one sewing system can carry out overlock seams (at best with cutting off the projection) and the other sewing system can carry out coverstitch seams, for example.

[0060] According to a further aspect, a program element for robot-assisted sewing of fabric layers for clothing, which program element, when executed by a processor, is configured to carry out the method described above. By means of the program element, instructions for controlling a computer system can be given in order to coordinate the carrying out of the method described above.

[0061] The computer program can be implemented as computer-readable command code in any suitable programming language, such as JAVA, C++, for example, and can be stored on a computer-readable medium (removable disk, volatile or non-volatile memory, embedded memory / processor, etc.). With the command code, a computer or another programmable device can be programmed in such a way that it carries out the intended functions. The computer program can be made available via a network, such as the World Wide Web, for example, from which it can be downloaded. The disclosure can be realized with the aid of a computer program or software. However, the disclosure can also be realized by means of one or more specific electronic circuits or hardware. Furthermore, the disclosure can also be realized in a hybrid form, i.e. in a combination of software and hardware modules.

[0062] According to a further exemplary embodiment of the system, the handling mechanism is selected from the group consisting of grippers, suction units, clamps, regions with increased friction and / or electrostatic attraction, rollers, freezing grippers, and / or Bernoulli grippers.

[0063] Electroadhesive grippers for electrostatic attraction work with electrostatic fields. Holding forces are generated by polarization. They can be generated on the upper side of the fabric layer, which is in contact with a gripper dielectric of the electroadhesive gripper.

[0064] A Bernoulli gripper has a suction body, wherein compressed air is flowed to the outside between the fabric part and the suction body along the x-y plane via a flow channel of the suction body at the edge regions of the suction body. An air opening, which is coupled to the flow channel, is located in the center of the suction body. Due to the Bernoulli effect, air is sucked into the flow channel from the direction of the fabric part. A fixing force of the fabric part on the suction body thus arises.

[0065] A freezer gripper has a strongly cooled contact surface with the fabric part, as a result of which frozen water or ice as an adhesive adheres the fabric part to the contact surface. The water can be drawn as an adhesive from the atmosphere (air humidity) or can be added by an adhesive supply.

[0066] According to a further exemplary embodiment, the handling mechanism comprises holding needles, which penetrate at least into the first fabric layer, the second fabric layer and / or the fabric layer stack in order to fasten them to the effector. Furthermore, a penetration depth and / or a penetration angle of at least one holding needle can be controllable, in particular in real time and / or based on a sensor feedback. An additional form of differentiated gripping by the handling mechanism can relate to the depth of a holding needle and / or the angle of a holding needle (and in particular a plurality thereof). Thus, for example, a holding needle can be inserted into the fabric layer during singulation at a shallow angle or not so deep, while during the fastening of two fabric layers (for the joining) a steeper angle or a larger penetration depth can be used to securely grip both fabric layers.

[0067] According to a further exemplary embodiment, holding needles have a diameter of less than 1300 micrometers, less than 900 micrometers, in particular less than 550 micrometers, further in particular less than 250 micrometers. It has been found that in the case of fine microneedles as holding needles in combination with a suitable vacuum negative pressure and a suitable air flow, no quality-disturbing effects remain on the fabric surface after the processing. This has been shown especially in the case of needle diameters of less than 1300 micrometers, less than 900 micrometers, in particular less than 550 micrometers, preferably less than 250 micrometers.

[0068] According to a further exemplary embodiment, holding needles are arranged at a control surface of the handling mechanism, wherein a surface shape of the control surface is adjustable such that in a first configuration of the surface shape the holding needles are oriented parallel to each other in order to penetrate into or move out of at least one fabric layer, and in a second configuration of the surface shape the holding needles are not oriented parallel to each other in order to fix them in at least one fabric layer.

[0069] As a result of the bending of the control surface, the holding needles spread apart and fix the two fabric layers. In the case of a bending back of the control surface, for example a uniform movement or abruptly by means of a clicking back, the holding needles, which are in particular again oriented parallel to each other, are released again from the fabric layers. By means of a handling mechanism configured in this way, in particular in the case of two-layer stacking of fabric layers, the fixing at the handling mechanism can be removed again gradually within the course of the sewing progress.

[0070] According to a further exemplary embodiment, the surface shape of the control surface is deformable and in particular pre-tensionable by means of mechanical or hydraulic elements. Furthermore, the control surface can be configured to be elastically deformable, so that it can be pre-tensioned and is automatically deformed back without an external restoring force into a starting position, for example by the holding needles running parallel or by the holding needles having an angle to each other. The control surface can move back continuously into a starting position. Furthermore, for example, the control surface can comprise a material with a memory effect, and abruptly click back or snap back into a starting position.

[0071] According to a further exemplary embodiment, the effector comprises an abutment surface within an effector contour, at which one of the fabric layers or the fabric layer stack can abut. The abutment surface in particular forms a part of the handling mechanism for fixing one of the fabric layers or the fabric layer stack, wherein the abutment surface is configured to hold one of the fabric layers or the fabric layer stack magnetically, based on air pressure, mechanically or electrostatically on the effector.

[0072] The abutment surface allows the fabric layers or the fabric layer stack to be transported in a warp- and fold-free manner and to be deposited later. After the positioning or stacking of the fabric layers, the fabric layers can be fixed more easily with the abutment surface. The abutment surface can for example be part of the magnetic device and can be configured to be correspondingly magnetic. Furthermore, the abutment surface can hold the fabric layers with negative pressure, with mechanical elements (for example continuous microneedles) or with electrostatic elements.

[0073] According to a further exemplary embodiment, the abutment surface forms a suction surface as part of the handling mechanism, at which one of the fabric layers or the fabric layer stack can abut. The suction surface comprises a plurality of suction openings, in particular more than 9, more than 15, more than 22 and / or more than 30 suction openings, wherein the suction openings are in particular configured with a diameter of less than 20 mm, in particular less than 10 mm, further in particular less than 5 mm, further in particular less than 3 mm. With a handling mechanism based on negative pressure, sufficient force can be generated with a small suction opening only with high negative pressure in order to hold the fabric layers. The fabric layer deforms, which could in particular make the ironing necessary in a next work step. On the other hand, large suction openings deform the textile material so strongly even with little negative pressure that it no longer lies sufficiently flat in the x-y plane. In addition, during the positioning on another fabric layer, the latter can also still be sucked, which counteracts the exact positioning. For this reason, a solution was selected which uses a plurality of small suction openings (which are distributed over a larger area or edge). The experiments with respect to smaller diameters of these suction openings have shown that the fabric layers hold in a planar manner in the x-y plane. This in particular prevents warping and fold formation for the later laying down.

[0074] According to a further exemplary embodiment, a negative pressure on the suction surface for holding the fabric layers or the fabric layer stack is adjustable such that the negative pressure is variable by more than 15%, in particular more than 30% or by more than 45%. In the exemplary embodiment in which the handling mechanism is implemented by means of a suction unit, a gripping function is achieved by means of negative pressure. The suction unit comprises a suction cup or a suction bell, to which a vacuum pump or a suction pump is connected in order to suck air out of the suction cup. A negative pressure is generated in the volume between the fabric part and the suction cup, with which negative pressure a fixing force is generated. The negative pressure can, for example, be measured by means of sensors in order to accordingly control the suction power by means of the control device.

[0075] The suction power or the negative pressure can be adjusted for different fabric types of the fabric parts. Good results have been achieved with the following negative pressure powers:Suction Power inSuction Power inType of fabric[Pa][mbar]Cotton 100% Interlock16020-18300160.20-183.00JerseyCotton-Tencel (66 / 33)17060-19240170.60-192.40InterlockCotton-Elastane (95 / 5)18720-22300187.20-223.00Single JerseyDenim13400-15600134.00-156.00100% Polyester - Plain25370-27800253.70-278.00weave

[0076] The control unit and the vacuum pump can be configured such that a negative pressure can vary by more than 15%, in particular more than 30%, preferably by more than 45%. A high adaptability to different fabrics is thus enabled. Furthermore, the error sources of an incorrect fixing, suction at the work table and slip during the sewing can thus be significantly reduced.

[0077] According to a further exemplary embodiment, the fixing mechanism comprises a welding device, in particular an ultrasonic welding device, for, in particular temporarily, welding together the first and second fabric layers, wherein the fixing mechanism comprises in particular a feeding device for feeding welding material. Depending on the material property, a plastic welding technique, in particular ultrasonic welding, can be used. A suitable auxiliary material (ultrasonic welding tape, hot-melt adhesive, etc.) welding material can also be inserted beforehand (or during the welding process) by means of the feeding device. Alternatively, an adhesive can be placed beforehand by means of a metering device. For example, the effector can travel to a fabric layer stack. The feeding device can for example feed a solid welding material, such as for example a welding wire, or a viscous fluid, which solidifies under the effect of heat, in particular at the joining regions of the fabric layers lying on one another in the fabric layer stack. The feeding device can for example be fastened to the worktable or to the effector. Correspondingly, the fixing mechanism comprises a heat generator of the welding element which heats the welding material in the region of the joining region in the fabric layers, with the result that a weld seam can be produced.

[0078] According to a further exemplary embodiment, the fixing mechanism comprises a suction device with at least one sucking unit, wherein the suction device is configured to suck air from the first and second fabric layers by means of the sucking unit in such a way that the first and second fabric layers lying on one another can be fixed to the suction device.

[0079] According to a further exemplary embodiment, the fixing mechanism comprises a magnetic device, which is configured to attract a magnetic element in the direction of the effector in such a way that the fabric layers, which can be arranged between the effector and the magnetic element, can be fixed. Since the fabric layers are permeable to air to a certain degree due to their material characteristic, two or more fabric layers can be fastened in a fabric layer stack by means of suction with a correspondingly adjusted suction power. The suction device comprises, for example, a vacuum pump, which can be arranged spaced apart from the effector, for example at the work table. One or more sucking units, such as suction cups, for example, can be fastened to the effector as part of the fixing mechanism. Furthermore, the suction device with the sucking units can also form parts of the handling mechanism in order to align and convey the fixed fabric layers. In an exemplary embodiment, the suction device also forms parts of the handling mechanism for handling the fabric layers.

[0080] According to a further exemplary embodiment, the fixing mechanism comprises a clamping device, which is configured to clamp the first fabric layer and the second fabric layer together.

[0081] According to a further exemplary embodiment, the fixing mechanism comprises an adhesive device, which is configured to provide a temporary gluing together of the first fabric layer and the second fabric layer. In addition, the adhesive device can comprise a heating element, such as for example a heated bar or a hot-air heater, in order for example to enable hot gluing. In particular, different adhesive materials, such as for example quick-release adhesives, contact adhesives, pressure-activated adhesives or welding adhesives (for example in the case of PVC materials) can be used.

[0082] The adhesives are configured such that an adhesive force is generated which enables a later release of the fabric layers. Furthermore, an adhesive can be configured to lose its adhesive effect under the effect of temperature or under the effect of certain radiation (for example UV radiation), with the result that the fabric layers can be released again after a joining step. Accordingly, the adhesive device can for example comprise a temperature control device or a radiation device, which is configured to release the adhesive connection. The temperature control device or the radiation device can for example be arranged at the work table. The adhesive device furthermore comprises in particular a feeding device, which is configured to provide a temporary gluing together of the first fabric layer and the second fabric layer by means of adding an adhesive.

[0083] According to a further exemplary embodiment, the fixing mechanism comprises a holding needle device, which is configured to introduce holding needles into the first fabric layer and the second fabric layer for fixing. By means of the holding needle device, either from the effector side, from the worktable side or from an auxiliary system (e.g. auxiliary plate, needle band), one or more needle-like pins or holding needles can be driven from a magazine into or through the fabric layers in order to fasten them to each other. The holding needle device comprises in particular a feeding device, for example a holding needle magazine, which is configured to feed holding needles for the holding needle device.

[0084] According to an exemplary embodiment, the fixing mechanism comprises a stapling device, which is configured to introduce at least one staple into the first fabric layer and the second fabric layer for fixing, wherein the stapling device comprises in particular a feeding device, which is configured to feed staples for the stapling device.

[0085] According to a further exemplary embodiment, the fixing mechanism comprises a hold-down device, which is configured to apply a pressing force to the first fabric layer and the second fabric layer in the direction of the work surface. The hold-down device can press with a force against the work table / the work surface, which leads to a fixing of the two intermediate fabric layers. Alternatively, the effector can also allow compressed air to flow in between its underside and the fabric layers. This is in particular helpful when the effector has to reposition itself so that it can quickly overcome the adhesive forces between the effector and the first fabric layer.

[0086] According to a further exemplary embodiment, the handling mechanism comprises a support element, in particular a support plate, for supporting the fabric layer stack to be conveyed, wherein the handling mechanism in particular is configured such that the first fabric layer and second fabric layer fixed by the fixing mechanism can be lifted together and the support element can be conveyed below the fixed first fabric layer and second fabric layer. The support element can for example have a fork shape, or the support plate can comprise a round support surface or an angular support surface. Furthermore, the support element can comprise an adhesive surface, with the result that the fabric layers do not slide down unintentionally during transport or joining. The support element can for example (e.g. via a further robot arm) be arranged in an articulated manner on the effector in order to be inserted accordingly below or between the fabric layers.

[0087] In other words, the uppermost fabric layer or the uppermost fabric layers of a fabric layer stack can thus be lifted. For this purpose, the handling mechanism can lift the uppermost fabric layer or at least one rim or one edge by means of the explained exemplary embodiments (e.g. by means of a temporary adhesive, with holding needles or microneedles, by means of a Bernoulli gripper or by means of suction devices or vacuum), with the result that the support element can be moved in between, i.e. can subsequently be transported between the uppermost fabric layer(s) and the underlying fabric layers or the work table. In other words, the support element initially moves in the x- or y-direction below the fabric layer to be lifted, with the result that at the beginning the front edge of the support element is parallel to the straight cut edge of the fabric layer. When the support element is completely (or at least) pushed under, the support element together with the fabric layer to be lifted is lifted vertically or in the z-direction and thus singulated from the rest of the underlying fabric layers.

[0088] In summary, the following process sequence can be carried out with the method according to the disclosure:

[0089] A) gripping and positioning a fabric layer by the handling mechanism of a handling robot

[0090] B) fixing two fabric layers one above the other by means of the fixing mechanism, wherein the action of the effector for the fixing by means of the fixing mechanism differs from the action for the gripping (step A) by means of the handling mechanism and the fixing by means of the fixing mechanism takes place with the aid of at least one action from the list: welding, sucking, folding, magnetically fixing, clamping, adhesive bonding, fastening, holding-down, pressing together, penetrating and / or piercing.

[0091] C) feeding the two fabric layers to a sewing machine, wherein the regions to be sewn, i.e. the joining regions, of the fabric layers form a projection,

[0092] D) sewing these fabric layers with the assistance of a continuous guidance of the handling mechanism

[0093] E) guiding the sewn parts away from the sewing machine by the handling mechanism.

[0094] The provided projection of multi-layered fabric is the requirement for subsequent automated sewing. For this purpose, the fabric stack already placed in a flat and horizontal manner is fed with the handling robot to a sewing machine (controlled by the automation system) and sewn. The handling robot guides the fabric stack in coordination with the feed motion (i.e. the forward and return transport via the sewing feet) of the sewing machine. The sewing machine can comprise both an upper transporter and / or a lower transporter (fabric transport through the stitch plate). Furthermore, the sewing machine can be equipped without a transporter. In a further exemplary embodiment, the sewing foot described above can be used as a transporter. A triple transport can also be used, in which, in addition to the upper and lower transporters, the needle is also moved along (especially in the case of stiff woven fabrics). By fixing the fabric layers and carrying along the robot (takes over the fabric weight in the case of heavy fabrics), a clean transport and thus a good seam quality can be achieved. Thus, further transport aids such as sewing in paper, powders, oils, etc. can be dispensed with. In particular, a piece of clothing can thus be produced without subsequent washing and ironing.

[0095] The guidance by the robot can, however, also allow different feeds of upper and lower fabric if the fabric layers are not fixed on top of each other but the fixing is focused on separately guidable auxiliary constructions (e.g. thin plates). Thus, on the one hand, a holding / conveying device can be installed in the work table (e.g. with electrostatic holding or electrostatic transport [similar to a linear motor]), which transports the lower fabric layer and the robot arm with the effector fixes the upper fabric layer. Thus, different travel paths for the upper and lower fabric can be guided during the sewing, which allows certain 3D effects after the sewing process. There exist sewing machines which allow this different transport of upper and lower fabric. With the solution according to the disclosure, however, correspondingly automated productions can thus be achieved. The introduction of the two fabric layers into the different transport devices of the sewing machine can be realized by separate movements of the different feeds (as explained at the beginning of this section), however, it can also be realized by different widths of a projection of a stitched double layer (and the stitching is then released, e.g. cut off, in the sewing process).

[0096] It is pointed out that the embodiments described here represent only a limited selection of possible embodiment variants of the disclosure. It is thus possible to combine the features of individual embodiments with each other in a suitable manner, with the result that a multiplicity of different embodiments are to be regarded as obviously disclosed for the person skilled in the art with the embodiment variants explicit here. In particular, some embodiments of the disclosure are described with device claims and other embodiments of the disclosure are described with method claims. However, the person skilled in the art will immediately understand when reading this application that, unless explicitly stated otherwise, in addition to a combination of features which belong to a type of subject matter of the disclosure, an arbitrary combination of features which belong to different types of subject matter of the disclosure is also possible.BRIEF DESCRIPTION OF THE DRAWINGS

[0097] Exemplary embodiments are described in more detail below with reference to the appended drawings for further explanation and for a better understanding of the present disclosure. In the drawings:

[0098] FIG. 1, FIG. 2, FIG. 3 and FIG. 4 show schematic illustrations of a method for handling and processing fabric layers according to an exemplary embodiment.

[0099] FIG. 5 shows a schematic illustration of a handling mechanism which holds a fabric layer stack within an effector contour.

[0100] FIG. 6 shows a schematic illustration of a magnet device as a fixing mechanism according to an exemplary embodiment.

[0101] FIG. 7 shows a schematic illustration of an effector with a contact surface according to an exemplary embodiment.

[0102] FIG. 8 shows a schematic illustration of an effector with a handling mechanism and a fixing mechanism according to an exemplary embodiment.

[0103] FIG. 9 shows a schematic illustration of a worktable with adjustable static friction on the work surface according to an exemplary embodiment.

[0104] FIG. 10 shows a schematic illustration of a handling mechanism with a gripping device according to an exemplary embodiment of the present disclosure.

[0105] FIG. 11 shows a schematic illustration of a handling mechanism with a suction device according to an exemplary embodiment of the present disclosure.

[0106] FIG. 12 shows a schematic illustration of a handling mechanism with an electrostatically charged element according to an exemplary embodiment of the present disclosure.

[0107] FIG. 13 shows a schematic illustration of a handling mechanism with holding needles according to an exemplary embodiment of the present disclosure.

[0108] FIG. 14 shows a schematic illustration of an effector with a plurality of different handling mechanisms, for example with a suction device and holding needles according to an exemplary embodiment of the present disclosure.

[0109] FIG. 15 shows a schematic illustration of a handling mechanism with a gripper, which grips an upper side of a fabric layer, according to an exemplary embodiment of the present disclosure.

[0110] FIG. 16 shows a schematic illustration of a handling mechanism with a suction surface according to an exemplary embodiment of the present disclosure.

[0111] FIG. 17, FIG. 18 and FIG. 19 show schematic illustrations of a fixing mechanism with a folding device according to an exemplary embodiment of the present disclosure.

[0112] FIG. 20 shows a schematic illustration of the folding device, which is arranged on a worktable, according to an exemplary embodiment of the present disclosure.

[0113] FIG. 21 shows a schematic illustration of fabric layers with a protrusion outside an effector contour, according to an exemplary embodiment.

[0114] FIG. 22, FIG. 23 and FIG. 24 show schematic illustrations of a handling mechanism with holding needles according to an exemplary embodiment.

[0115] FIG. 25 shows a schematic illustration of a positioning of a third fabric layer on two already sewn fabric layers according to a further exemplary embodiment.DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

[0116] Identical or similar components in different figures are provided with identical reference numerals. The illustrations in the figures are schematic.

[0117] FIG. 1, FIG. 2, FIG. 3 and FIG. 4 show schematic illustrations of a method for robot-assisted sewing of fabric layers 111, 112 for clothing. The method comprises gripping a first fabric layer 111 or second fabric layer 112 by a handling mechanism 120 of a handling robot 100 with an effector 101 for handling fabric layers 111, 112 (see FIG. 1). The first fabric layer 111 is positioned above a second fabric layer 112 which rests on a worktable 103 (see FIG. 2) and the first fabric layer 111 is fixed with the second fabric layer 112 to form a fabric layer stack 113 by means of a fixing mechanism 130 which is arranged at least partially at the effector 101 in such a way that a joining region 114 of the first fabric layer 111 rests on a further joining region 115 of the second fabric layer 112 (see FIG. 3). Furthermore, the fabric layer stack 113 is fed to a sewing machine 140 by means of the handling mechanism 120, wherein the joining regions are freely accessible for the sewing machine 140. The joining regions are sewn, wherein during the sewing the handling mechanism 120 guides the fabric layer stack 113 relative to the sewing machine 140 (see FIG. 4). The sewn fabric layer stack 113 is fed by means of the handling mechanism 120 from the sewing machine 140 to a depositing location.

[0118] The handling robot 100 comprises the effector 101 on which the corresponding handling mechanism 120 is, in particular exchangeably, attached. The handling robot 100 is fastened with a stationary robot base on the floor in order to introduce corresponding forces into the floor. A robot arm 104 is arranged between the effector 101 and the robot base, which robot arm comprises, for example, one or more joints in order thus to control the effector 101 into a desired position. In particular, the handling robot 100 is configured to handle or manipulate the fabric layers 111, 112 and to move and position them accordingly.

[0119] The handling robot 100 and the corresponding handling mechanism 120, the fixing mechanism 130 and / or the sewing machine 140 (or another joining unit) are coupled by means of a control unit 105, such that fully automatic positioning of the fabric layers 111, 112 and subsequent joining can be carried out.

[0120] The controllable handling mechanism 120 and the fixing mechanism 130 are arranged at the effector 101. The fixing mechanism 130 is configured to fasten at least two fabric layers 111, 112 which in particular lie one on top of each other so that the fixed two fabric layers 111, 112 can be conveyed in particular as a package or as a fabric layer stack 113.

[0121] In particular, the handling mechanism 120 can convey a fabric layer 111 or the described fabric layers 111, 112 fixed together, for example to the sewing machine 140 or another sewing machine. The effector or the handling mechanism 120 can adapt to the contour of the fabric layers 111, 112, for example by fixing points of the handling mechanism 120 being adjustable at which the fabric layers 111, 112 are fixed. For example, the fixing elements 901 shown in FIG. 9 can be arranged for this purpose in which the individual fixing points are formed.

[0122] The fixing mechanism 130 is arranged completely at the effector 101 in an exemplary embodiment. For example, however, a part of the fixing mechanism 130 can also be arranged at a work table 103 on which, for example, the fabric layers 111, 112 are placed. Correspondingly, the handling mechanism 120 is fastened completely to the effector 101, but a part of the handling mechanism 120 can also be fastened to the work table 103.

[0123] The effector 101 thus forms an end part of the handling robot 100 with, for example, a suction device as a handling mechanism 120 which grips and manipulates a fabric layer 111, 112 or a fabric layer stack 113 which consists of fabric layers 111, 112 which are fastened by the fixing mechanism 130.

[0124] The sewing machine 140 is configured to process the joining regions of a fabric layer 111, 112 and / or to connect at least two fabric layers 111, 112. The sewing machine 140 can be a sewing machine, a welding machine, a stapling machine, a crocheting machine, an automatic gluing machine or further automatic connecting machines for fabric layers 111, 112.

[0125] FIG. 1 shows the handling robot 100 which, by means of a suction device as a handling mechanism 120, places a fabric layer 112 on a work surface 102 of the work table 103. The work surface 102 aligns itself in a horizontal x, y plane. The effector 101 can be moved, for example, along the horizontal plane and in the vertical direction z.

[0126] Next, as illustrated in FIG. 2, a first fabric layer 111 can be placed by means of the suction device as a handling mechanism 120 onto the second fabric layer 112, which is already placed on the work table. The fabric layers 111, 112 are oriented relative to each other such that, for example, the joining regions 114, 115 here, at which the two fabric layers 111, 112 are to be connected, for example by means of a seam, lie one above the other and are oriented.

[0127] In a next step, as illustrated for example in FIG. 3, the fixing device 130 on the effector 101 is activated. In the exemplary illustration, the fixing mechanism 130 comprises a holding needle device 131, which penetrates holding needles 132 through the two fabric layers 111, 112 in order to hold these two to each other in a fabric layer stack 113.

[0128] Subsequently, as illustrated in FIG. 4, the handling mechanism 120 is in turn activated by, for example, a suction cup / suction unit generating negative pressure and thus fastening the fabric layer stack 113 to the effector 101. The effector 101 is subsequently conveyed together with the fabric layer stack 113 to the sewing machine 140, with the result that the joining regions 114, 115 are exactly positioned in the processing region of the sewing machine 140. Subsequently, the sewing machine 140 can process the joining regions 114, 115.

[0129] FIG. 5 shows a schematic illustration of a handling mechanism 120 which holds a fabric layer stack 113 within an effector contour 501. The fixing mechanism 130 or the handling mechanism 120 comprises an effector contour 501 with a fixing surface within the outer joining regions 114, 115, in which fixing surface a fixing force can be transmitted to at least the fabric layers 111, 112.

[0130] The effector contour 501 describes the region on a fabric layer 111, 112 at which the fixing mechanism 130 and / or the handling mechanism 120 exerts a fixing or holding force. The effector contour 501 is defined, for example, by the outline of the fixing surface or by the connecting lines between the individual fixing points at which a holding contact with a held fabric layer 111, 112 is present within the x-y plane. In the illustration in FIG. 5, a plurality of holding needles 132 have been introduced by the holding needle device 131 in order to hold the two fabric layers 111, 112 together. The connecting lines form the effector contour 501 within the fabric layer 111, 112. At the outer edge regions of the fabric layers 111, 112 which lie outside the effector contour 501 which is defined by the fixing points at which the handling mechanism holds the fabric layers 111, 112, the joining regions 114, 115 are formed and the fabric layer 111, 112 can be present untensioned there and project so to speak out of the x-y plane.

[0131] FIG. 6 shows a schematic illustration of a magnet device as a fixing mechanism 130. The magnet device comprises a magnetic element 601. The magnet device can attract the magnetic element 601 in the direction of the effector 101 in such a way that the fabric layers 111, 112, which can be arranged between the effector 101 and the magnetic element 601, can be fixed. The magnetic element 601 can for example form a flat magnetic disk which lies under a lower fabric layer 111, 112 on the work table 103. Further fabric layers 111, 112 can be placed over the lower fabric layers 111, 112. The magnet device at the effector 101 can for example comprise a controllable electromagnet. The effector 101 can thus travel to the fabric layer stack 113 and activate the magnet device so that the magnetic element 601 arranged at the bottom is attracted in the direction of the magnet device or effector 101 and fixes the intermediate fabric layers 111, 112.

[0132] FIG. 7 shows a schematic illustration of an effector 101 with a contact surface 701 according to an exemplary embodiment. The abutment surface 701 is formed within the effector contour 501, at which one of the fabric layers 111, 112 or the fabric layer stack 113 can abut. The abutment surface 701 in particular forms a part of the handling mechanism 120 for fixing one of the fabric layers or the fabric layer stack 113, wherein the abutment surface 701 is configured to hold one of the fabric layers 111, 112 or the fabric layer stack 113 magnetically, based on air pressure, mechanically or electrostatically on the effector 101. The abutment surface 701 allows the fabric layers 111, 112 or the fabric layer stack 113 to be transported in a warp- and fold-free manner and to be deposited later. After the positioning or stacking of the fabric layers 111, 112, the fabric layers can be fixed more easily with the abutment surface 701.

[0133] The work surface 102 comprises a support device 702, which is configured to fix one of the fabric layers 111, 112 or the fabric layer stack 113 on the work surface 102 by means of a support force, in particular by means of pneumatic, mechanical and / or electrostatic support forces. The support device 702 is for example fastened to the worktable 103. The support device 702 can be based on pneumatic, electrostatic or magnetic principles. Thus, for example, a ferromagnetic plate can lie on the work table 103, on which a fabric layer 111, 112 is deposited, which can later serve as magnetic element 601 of the magnet device.

[0134] FIG. 8 shows a schematic illustration of an effector 101 with a handling mechanism 120 and a fixing mechanism 130 according to an exemplary embodiment. For example, the effector 101 can first be placed over a fabric layer stack 113 in order to introduce holding needles 132 into the fabric layers 111, 112 so that the fabric layers 111, 112 are fastened to each other. In a next step, the effector 101 can be placed with the handling mechanism 120, which for example comprises a suction device, over the fabric layer stack 113 in order to hold the latter at the effector 101 and to be transported further to a sewing machine 140.

[0135] FIG. 9 shows a schematic illustration of a worktable 103 with adhesion regions 901 with different static friction, in particular with adjustable static friction. The handling mechanism 120 takes into account the different adhesion regions for aligning fabric layers 111, 112 when positioning the first fabric layer 111, the second fabric layer 112 or the fabric layer stack 113. The worktable 103 can comprise zones of different friction / adhesion. It can thus be advantageous if the lower fabric layer 112 does not slip during the precise placement for the fixing because it has a high friction / adhesion with respect to the work surface (while the upper fabric layer 111 is placed thereon). If both fabric layers 111, 112 are then fixed by means of the fixing mechanism 130, the robot can lift the fabric layers 111, 112 by means of the handling mechanism 120 and reposition them into a region with better sliding capacity for the sewing or the adhesion to the work surface can be switched off.

[0136] The roughness of the work surface 102 of the work table 102 can be adjusted by providing, for example, retractable and extendable bristles 902. The bristles 902 can extend at right angles to the work surface 102 of the work table 103. Additionally or alternatively, bristles 901 can have an angle of less than 90° to the work surface 102 of the work table 103. Thus, a different friction can be adjusted depending on the direction of movement of the fabric layers 111, 112 over the bristles 902. In an exemplary embodiment, a control unit can control the extension of the bristles 902. Furthermore, the angle of the bristles can be adjusted in order to thus adjust the friction 902 and in particular the direction of friction with respect to the fabric layers 111, 112 over the bristles 902.

[0137] FIG. 10 shows a schematic illustration of a handling mechanism 120 with a gripping device according to an exemplary embodiment of the present disclosure. A gripper 1001 of the gripping device is configured such that it encloses the edge of the fabric layer stack 113 and grips the fabric layer stack 113 from above from below, i.e. from the left and from the right side of the fabric layer stack 113.

[0138] FIG. 11 shows a schematic illustration of a handling mechanism 120 with a suction device according to an exemplary embodiment of the present disclosure. The suction device comprises a sucking unit 1101, wherein the suction device is configured to suck air from the first and second fabric layers 111, 112 by means of the sucking unit 1101 in such a way that the first and second fabric layers 111, 112 lying on one another can be fixed to the suction device. Since the fabric layers 111, 112 are permeable to air to a certain degree due to their material characteristic, two or more fabric layers can be fastened in a fabric layer stack 113 by means of suction with a correspondingly adjusted suction power. The suction device comprises, for example, a vacuum pump, which can for example be arranged spaced apart from the effector, for example at the work table 103.

[0139] FIG. 12 shows a schematic illustration of a handling mechanism 120 with an electrostatically charged attraction element 1201 according to an exemplary embodiment of the present disclosure. The electrostatically charged attraction element 1201 can for example be electrostatically charged in order to thus correspondingly fix the fabric material of the fabric layers 111, 112. The electrostatic charging can for example be generated via a correspondingly connected current generating device, which is controlled by the control unit 105.

[0140] FIG. 13 shows a schematic illustration of a handling mechanism 120 with holding needles 1301 according to an exemplary embodiment of the present disclosure. The handling mechanism 120 comprises a holding needle device, which is configured such that a penetration depth and / or a penetration angle of at least one holding needle 1301 is controllable, in particular in real time and / or based on a sensor feedback. An additional form of differentiated gripping by the handling mechanism 120 can represent the depth of a holding needle 1301 and / or the angle of a holding needle 1301 (and in particular relate to a plurality thereof).

[0141] FIG. 14 shows a schematic illustration of an effector 101 with a plurality of different handling mechanisms 120, for example with a suction device 1101 and holding needles 1301 according to an exemplary embodiment of the present disclosure.

[0142] FIG. 15 shows a schematic illustration of a handling mechanism 120 with a gripper 1001, which grips an upper side of a fabric layer, according to an exemplary embodiment of the present disclosure. The gripper 1001 grips a region of a surface of the fabric layer stack 113 in the manner of tongs.

[0143] FIG. 16 shows a schematic illustration of a handling mechanism 120 with a suction surface 1601 according to an exemplary embodiment of the present disclosure. The suction surface 1601 forms an abutment surface 701 as part of the handling mechanism 120, at which one of the fabric layers 111, 112 or the fabric layer stack 113 can abut. The suction surface 1601 comprises a plurality of suction openings 1602.

[0144] FIG. 17, FIG. 18 and FIG. 19 show schematic illustrations of a fixing mechanism 130 with a folding device according to an exemplary embodiment of the present disclosure. The folding device is configured to fold an edge region of a fabric layer 111 in such a manner that the folded edge region forms the first fabric layer 111 which rests on the second fabric layer 112. The folding device comprises a clamping element 1703 in order to clamp the folded first fabric layer 111 and the second fabric layer 112 together.

[0145] The folding device is fastened to the worktable 103 by means of a bearing 1704. A fixed support beam 1702 is arranged at the bearing 1704. Furthermore, the folding device comprises a movable folding beam 1701, which is movably arranged at the bearing 1704. The folding beam 1701 runs parallel to the support beam 1702 and can be pivoted around this support beam 1702. The folding beam 1701 and the support beam 1702 run parallel (and e.g. horizontally) to the work surface 102.

[0146] As illustrated in FIG. 17, a fabric layer 111 is fastened to the effector 101 at a suction surface 1601. Furthermore, a pivotable clamping element 1703 is arranged at the effector 101 or the suction surface 1601 at the effector 101. The clamping element 1703 can be pivoted over an axis of the effector 101 or the suction surface 1601. In an initial position, the folding beam 1701 and the support beam 1702 are spaced apart so that a region of the fabric layer 111 can be positioned between the folding beam 1701 and the support beam 1702.

[0147] Subsequently, as illustrated in FIG. 18, the folding beam 1701 is pivoted around the support beam 1702, wherein the folding beam 1701 continues to remain parallel to the support beam 1702 and carries along a region of the fabric layers 111 and thus folds it around the support beam 1702. Accordingly, as a result, two fabric layers 111, 112 lie one on top of each other. Between the effector 101 and / or the suction surface 1601 and the folding beam 1701, in particular the joining region 115 and / or an edge region of the second fabric layer 112 is present. Subsequently, the clamping element 1703 is pivoted out over the edge of the effector 101 or the suction surface 1601 and clamps the two fabric layers 111, 112 together.

[0148] For this purpose, the effector 101 or the suction surface 1601 comprises a contact region 1705 on which an edge region of the folded second fabric layer 112 lies, with the result that the clamping element 1703 can clamp this edge region and / or can press it against the contact region 1705. The contact region 1705 can comprise a projection at the effector 101 and / or the suction surface 1601 which extends from an edge of the effector 101 and / or the suction surface 1601 and around which the fabric layer 112 lies after the folding. In other words, the projection is arranged between the two fabric layers 111, 112 after the folding.

[0149] Furthermore, the length of the folded second fabric layer 112 can be longer than a distance between an edge of the effector 101 or the suction surface 1601 and the support beam 1702. An end region of the folded second fabric layer 112 is thus folded up and placed against the edge surface. The clamping element 1703 subsequently pivots in the direction of the edge surface and clamps the folded-up part of the second fabric layer 112.

[0150] As illustrated in FIG. 19, the effector 101 can pull out the fabric layers 111, 112 horizontally in the extension direction of the folding beam 1701 and the support beam 1702, wherein the fabric layers 111, 112 are held in the folded position by means of the clamping element 1703. The effector 101 can now be pivoted into a horizontal position, with the result that the fabric layers 111, 112 can rest in a flat manner on the worktable 103. The clamping element 1703 continues to clamp the fabric layers 111, 112 together. The joining regions 114, 115 at which the sewing machine 140 can, for example, place a seam are illustrated at the free end.

[0151] FIG. 20 shows a schematic illustration of the folding device, which can be arranged on a worktable 103. The folding beam 1701 and the support beam 1702 are fastened at one end to the bearing 1704. Free ends are provided at the opposite ends of the folding beam 1701 and of the support beam 1702. After the fabric layers 111, 112 have been folded by means of the folding beam 1701, the effector 101 can be moved horizontally, with the result that the folding beam 1701 is moved out of the pocket formed between fabric layers 111, 112.

[0152] FIG. 21 shows a schematic illustration of a fabric layer 111 with a protrusion 2101 outside an effector contour 501, according to an exemplary embodiment. The fabric layer 111 has, for example, the form of an outer skirt. The second fabric layer 112 is arranged below the fabric layer 111. The first fabric layer 111 comprises a plurality of fixing regions 2100. The fixing points of the handling mechanism 120 and / or of the fixing mechanism 130 grip at the fixing regions 2100. At the edge of the inner effector contour 501, in particular fixing points of the handling mechanism 120 are provided in order to raise the first fabric layer 111 as far as possible tensionized in a fold-free manner. Fixing elements for the fixing mechanism 130 can be provided in the interior of the effector contour 501, at which fixing elements the fixing mechanism 130 fixes both fabric layers 111, 112 together. For example, corresponding holding needles 132 of the holding needle device 131 can be introduced at the fixing elements of the fixing mechanism 130 in order to fasten both fabric layers 111, 112 to each other.

[0153] The effector contour 501 is smaller than the outer contour of the fabric layers 111, 112, with the result that the projection 2101 is formed in this region between the outer contour of the fabric layers 111, 112 and the effector contour 501, in which projection in particular the joining region 114 is formed. The effector can thus convey the fabric layers 111, 112 to a sewing machine 140, with the result that the latter places a corresponding seam in the joining region 114.

[0154] FIG. 22, FIG. 23 and FIG. 24 show schematic illustrations of a handling mechanism 120 with holding needles 1301 according to an exemplary embodiment.

[0155] Holding needles 1301 are arranged at a control surface 2201 of the handling mechanism 120, wherein a surface shape of the control surface 2201 is adjustable such that in a first configuration of the surface shape the holding needles 1301 are oriented parallel to each other (see FIG. 22) in order to penetrate into or move out of at least one fabric layer 111, 112, and in a second configuration of the surface shape the holding needles 1301 are not oriented parallel to each other (see FIG. 23 or FIG. 24) in order to fix them in at least one fabric layer 111, 112.

[0156] As a result of the bending of the control surface, the holding needles 1301 spread apart and fix the two fabric layers 111, 112. In the case of a bending back of the control surface, for example a uniform movement or abruptly by means of a clicking back, the holding needles 1301, which are in particular again oriented parallel to each other, are released again from the fabric layers 111, 112. The surface shape of the control surface 2201 can be deformable and in particular pre-tensionable by means of mechanical, pneumatic or hydraulic elements. The control surface 2201 can be configured to be elastically deformable, so that it can be pre-tensioned and is automatically deformed back without an external restoring force into a starting position, for example by the holding needles 1301 running parallel or by the holding needles 1301 having an angle to each other.

[0157] In the exemplary embodiment shown, a control chamber 2202 is formed between the effector 101 and the control surface 2201. The control chamber can be supplied with air (or a gas, in a hydraulic embodiment a hydraulic liquid) via an air line 2203. For example, an overpressure can be generated in the control chamber 2202, as a result of which the control surface 2201 deforms outwards and the holding needles 1301 are correspondingly spread apart (see FIG. 23). Alternatively, air can also be drawn out of the control chamber 2202, so that a negative pressure is generated and the control surface 2201 deforms inwards (see FIG. 24). The holding needles 1301 are thus pushed together at their tips. A corresponding fabric layer 111, 112 can be held by means of the holding needles 1301 which are spread apart or pushed together.

[0158] FIG. 25 shows a schematic illustration of a positioning of a third fabric layer 2501 on two already sewn fabric layers 111, 112 according to a further exemplary embodiment. A first fabric layer 111 and a second fabric layer 112 lie partially one on top of the other on a work table 103 and have in particular already been sewn together with a seam 2503 by the method according to the disclosure. The handling mechanism 120 is equipped with a sucking unit 1101 which already holds a further third fabric layer 2501 within the effector contour 501. The edge regions of the third fabric layer 2501 are freely accessible and form a third joining region 2502. The effector 101 is controlled by means of the robot arm 104, with the result that the third fabric layer 2501 is placed over the first fabric layer 111. For example, the third joining region 2502 can thus lie over the seam 2503 and thus over the respective first and second joining regions 114, 115. Subsequently, the first fabric layer 111, the second fabric layer 112 and the third fabric layer 2501 can be sewn to each other. For example, the second fabric layer 112 can represent a tag or label and can thus be sewn into a kind of seam.

[0159] In addition, it should be noted that “comprising” does not exclude any other elements or steps and “a” or “an” does not exclude a plurality. Furthermore, it should be pointed out that features or steps which have been described with reference to one of the above exemplary embodiments can also be used in combination with other features or steps of other exemplary embodiments described above. Reference signs in the claims are not to be regarded as a restriction.List of reference signs:100 Handling robot101 Effector102 Work surface103 Worktable104 Robot arm105 Control unit111 First fabric part / fabric layer112 Second fabric part / fabric layer113 Fabric layer stack114 First joining region115 Further joining region120 Handling mechanism130 Fixing mechanism131 Holding needle device132 Holding needles140 Sewing machine501 Effector contour601 Magnetic element701 Effector contact surface702 Support device901 Adhesion region902 Bristles1001 Gripper1101 Sucking unit1201 Electrostatic attraction element1301 Holding needles1601 Suction surface1602 Suction opening1701 Folding beam1702 Support beam1703 Clamping element1704 Bearing at the worktable1705 Contact region2100 Fixing region2101 Projection2201 Control surface2202 Control chamber2203 Air line2501 Third fabric layer2502 Third joining region2503 Seam

Examples

Embodiment Construction

[0116]Identical or similar components in different figures are provided with identical reference numerals. The illustrations in the figures are schematic.

[0117]FIG. 1, FIG. 2, FIG. 3 and FIG. 4 show schematic illustrations of a method for robot-assisted sewing of fabric layers 111, 112 for clothing. The method comprises gripping a first fabric layer 111 or second fabric layer 112 by a handling mechanism 120 of a handling robot 100 with an effector 101 for handling fabric layers 111, 112 (see FIG. 1). The first fabric layer 111 is positioned above a second fabric layer 112 which rests on a worktable 103 (see FIG. 2) and the first fabric layer 111 is fixed with the second fabric layer 112 to form a fabric layer stack 113 by means of a fixing mechanism 130 which is arranged at least partially at the effector 101 in such a way that a joining region 114 of the first fabric layer 111 rests on a further joining region 115 of the second fabric layer 112 (see FIG. 3). Furthermore, the fabric...

Claims

1-33. (canceled)34. A method for robot-assisted sewing of fabric layers for clothing, the method comprising:gripping a first fabric layer by a handling mechanism of a handling robot with an effector for handling fabric layers;positioning the first fabric layer above a second fabric layer which rests on a worktable;fixing the first fabric layer with the second fabric layer to form a fabric layer stack by means of a fixing mechanism which is arranged at least partially at the effector in such a way that a joining region of the first fabric layer rests on a further joining region of the second fabric layer;feeding the fabric layer stack to a sewing machine by means of the handling mechanism, wherein the joining regions are freely accessible for the sewing machine;sewing the joining regions, wherein during the sewing the handling mechanism guides the fabric layer stack relative to the sewing machine; andhandling the sewn fabric layer stack by means of the handling mechanism from the sewing machine to a depositing location.

35. The method according to claim 34,wherein the handling mechanism singulates the second fabric layer from a plurality of fabric layers and deposits it in a flat manner on a work surface of the worktable, so that subsequently the first fabric layer is positioned above the second fabric layer.

36. The method according to claim 34, comprising at least one of the following features:wherein the first fabric layer and the second fabric layer form regions of a fabric part;wherein the positioning of the first fabric layer above the second fabric layer is carried out by folding the fabric part;wherein the first fabric layer is fixed with the second fabric layer by means of temporary fixing elements which are removed during sewing.

37. The method according to claim 34,wherein a work surface of the worktable comprises adhesion regions with different static friction and the handling mechanism takes into account the different adhesion regions for aligning the first fabric layer, the second fabric layer or the fabric layer stack when positioning the first fabric layer, the second fabric layer or the fabric layer stack,wherein the adhesion of the adhesion regions is controllable.

38. The method according to claim 37,wherein the handling mechanism moves the fabric layer stack over the adhesion regions such that the position of the lower second fabric layer is adjusted to the first upper fabric layer due to the static friction to the adhesion region.

39. The method according to claim 34, comprising at least one of the following features:wherein during the sewing the handling mechanism moves the fabric layer stack with a first feed motion relative to the sewing machine;wherein the sewing machine moves the fabric layer stack with a second feed motion;wherein after the step of sewing the method comprisesgripping a third fabric layer by the handling mechanism;positioning the third fabric layer above the sewn first and second fabric layers which rest on a worktable;fixing the third fabric layer with the sewn first and second fabric layers to form a fabric layer stack by means of the fixing mechanism in such a way that a further joining region of the third fabric layer rests on a further joining region of at least one of the first and second fabric layer;feeding the fabric layer stack to the sewing machine by means of the handling mechanism; andsewing the further joining regions, wherein during the sewing the handling mechanism guides the fabric layer stack relative to the sewing machine.

40. The method according to claim 34,wherein the fixing mechanism fixes the first and second fabric layers at least one of along at least one fixing region and along a plurality of spaced-apart fixing regions.

41. The method according to claim 40,wherein the fixing regions have an area of less than 1 cm2.

42. The method according to claim 40,wherein during or after sewing at least one of the fixing regions is separated.

43. The method according to claim 34, comprising at least one of the following features:wherein the work surface of the work table is movably mounted and moved;wherein the handling mechanism comprises an effector contour, wherein one of the fabric layers or the fabric layer stack can be fastened within the effector contour,wherein the effector contour is smaller than an outer contour of the fabric layer or the fabric layer stack,wherein the handling mechanism is configured such that the joining regions of the fabric layers form a protrusion with respect to the effector contour by more than 0.5 cm;wherein the handling mechanism introduces holding needles with at least one of a predetermined penetration depth and a predetermined penetration angle into the first fabric layer or the fabric layer stack by a holding needle device for fastening to the effector,wherein at least one of the predetermined penetration depth and the predetermined penetration angle is determined;wherein at least one of the fabric layers is fixed at the work surface by means of a hold-down device on the work table,wherein the hold-down device is configured to selectively fix at least one of the fabric layers at the work table;comprising at least one of:determining fabric layer data, anddetermining processing data, anddetermining at least one of positioning, placement, fixing during the sewing and the sewing quality, andevaluating the collected data for determining the quality of the sewn fabric layers;wherein the step of fixing comprises a feeding of adhesive for a temporary gluing together of the first fabric layer and the second fabric layer;wherein during sewing a seam end is detected,wherein during sewing at the seam end the feed motion of at least one of the handling device and the sewing machine is changed at the seam end in order to vary a tension of the fabric layers between the sewing machine and the effector in at least one of strength and direction;wherein after sewing a thread with a predetermined thread length is cut off after one end of the seam,wherein the handling mechanism moves the fabric layer stack relative to a thread cutting device such that the thread length is adjustable;wherein at least one of a heating device for heating the fabric layers and a moistening device for moistening the fabric layers is arranged at the work table in order to smooth at least one of at least one of the fabric layers and the fabric layer stack;wherein at least one further sewing device is arranged at the work table so that during or after sewing the joining regions the further sewing device sews further joining regions of the first and second fabric layers.

44. A program element for robot-assisted sewing of fabric layers for clothing, which program element, when executed by a processor, is configured to carry out the method according to claim 34.

45. A system for robot-assisted sewing of fabric layers for clothing, the system comprising:a handling robot with an effector, which comprises a handling mechanism for handling fabric layers,wherein the handling mechanism is configured to grip a first fabric layer,wherein the handling mechanism is configured to position the first fabric layer above a second fabric layer which rests on a worktable;a fixing mechanism which is arranged at least partially at the effector,wherein the fixing mechanism is configured to fix the first fabric layer and the second fabric layer to one another to form a fabric layer stack in such a way that a joining region of the first fabric layer rests on a further joining region of the second fabric layer; anda sewing machine,wherein the handling mechanism is configured to feed the fabric layer stack to the sewing machine, wherein the joining regions are freely accessible for the sewing machine,wherein the sewing machine is configured to sew the joining regions,wherein the handling mechanism is configured to guide the fabric layer stack relative to the sewing machine during the sewing,wherein the handling mechanism is configured to convey the sewn fabric layer stack from the sewing machine to a depositing location.

46. The system according to claim 45, comprising at least one of the following features:wherein the handling mechanism is selected from the group consisting of at least one of grippers, suckers, clamps, regions with at least one of increased friction and electrostatic attraction, rollers, freezing grippers, and Bernoulli grippers;wherein the sewing machine comprises a sewing foot with a sewing foot length in the conveying direction of the fabric layers to be sewn,wherein a sewing foot length in the conveying direction is larger than 20 mm, larger than 40 mm, or larger than 60 mm.

47. The system according to claim 45,wherein the handling mechanism comprises holding needles, which penetrate at least into at least one of the first fabric layer, the second fabric layer and the fabric layer stack in order to fasten them to the effector.

48. The system according to claim 47,wherein holding needles are arranged at a control surface of the handling mechanism,wherein a surface shape of the control surface is adjustable such that in a first configuration of the surface shape the holding needles are oriented parallel to each other in order to penetrate into or move out of at least one fabric layer, and in a second configuration of the surface shape the holding needles are not oriented parallel to each other in order to fix them in at least one fabric layer.

49. The system according to claim 48,wherein the surface shape of the control surface can be pre-tensioned by means of pneumatic, mechanical or hydraulic elements.

50. The system according to claim 45,wherein the effector comprises an abutment surface within an effector contour, at which one of the fabric layers or the fabric layer stack can abut,wherein the abutment surface is configured to hold one of the fabric layers or the fabric layer stack magnetically, based on air pressure, mechanically or electrostatically on the effector.

51. The system according to claim 50,wherein the abutment surface forms a suction surface as part of the handling mechanism, at which one of the fabric layers or the fabric layer stack can abut,wherein the suction surface comprises a plurality of suction openings.

52. The system according to claim 51,wherein a negative pressure on the suction surface for holding the fabric layers or the fabric layer stack is adjustable such that the negative pressure is variable by more than 15%.

53. The system according to claim 45, comprising at least one of the following features:wherein the fixing mechanism comprises a welding device for welding together the first and second fabric layers,wherein the fixing mechanism comprises a feeding device for feeding welding material, andwherein the fixing mechanism comprises a suction device with at least one sucking unit,wherein the suction device is configured to suck air from the first and second fabric layers by means of the sucking unit in such a way that the first and second fabric layers lying on one another can be fixed to the suction device, andwherein the fixing mechanism comprises a magnetic device, which is configured to attract a magnetic element in the direction of the effector in such a way that the fabric layers, which can be arranged between the effector and the magnetic element, can be fixed, andwherein the fixing mechanism comprises a clamping device, which is configured to clamp the first fabric layer and the second fabric layer together, andwherein the fixing mechanism comprises an adhesive device, which is configured to provide a temporary gluing together of the first fabric layer and the second fabric layer, andwherein the fixing mechanism comprises a holding needle device, which is configured to introduce holding needles into the first fabric layer and the second fabric layer for fixing, andwherein the fixing mechanism comprises a stapling device, which is configured to introduce at least one staple into the first fabric layer and the second fabric layer for fixing, andwherein the fixing mechanism comprises a hold-down device, which is configured to apply a pressing force to the first fabric layer and the second fabric layer in the direction of the work surface;wherein the handling mechanism comprises a support element for supporting the fabric layer stack to be conveyed.

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