AN ADAPTIVE FABRIC FOLDING END-EFFECTOR SYSTEM

Description

CROSS-REFERENCE TO RELATED APPLICATION(S)

The present application is a national stage entry under 35 U.S.C. § 371 of International Application No. PCT/CN2023/089266, filed on Apr. 19, 2023, which claims priority to International Application No. PCT/CN2022/090459, filed on Apr. 29, 2022. The contents of these applications are hereby incorporated by reference in their entirety.

BACKGROUND OF THE INVENTION

The global garment industry still relies heavily on manual handling and processing of fabric components. Folding of fabric parts prior to hemming or sewing is an essential and frequently performed procedure mainly carried out by human workers. For conventional folding tasks, the workers use an iron and a fixture or a guide to precisely fold each piece of the fabric. However, such folding methods are not adaptive for various shapes of the fabric due to the fixed geometry of the fixture designed for specific folding tasks, making it difficult and laborious for producing customized garments.

Taking shirts as an example, sewing, which includes stitching and seaming, ranks among the most frequently performed and most skill-demanding procedure of the garment construction workflows. A typical dress shirt may take up to 50-60 sewing operations and 25-30 minutes per human worker to complete. Edge-folding is a pre-requisite to sewing, where a piece of fabric part needs to be folded into a desired shape before being stitched onto a panel. Such process does not only take time but also requires adequate skills of the workers to ensure precision. An ill-folded fabric part induces variations to the sewing operations and may result in a defective product and wastage.

Although the folding tasks could be automated to some extent with the aid of industrial folding machines, the automatic folding only fits garments of certain sizes, shapes or styles, since the folding geometries are entirely fixed by a fixture or a clamp, making the approach only applicable to mass production of garments of given designs, but not customized garments that are highly sought after in the fashion market.

A great majority of patents related to automatic fabric folding focus on folding of sizable textile or fabric products such as shirts, pants, and towels. Few of them are related to freeform adaptive folding of individual fabric parts for producing garments.

For instance, U.S. Pat. No. 8,973,792 is related to a machine that was designed to fold finished fabric articles 43 such as shirts, jackets, and trousers. The machine employed rotating rods 44 and retractable tapes 45 to implement folding on a horizontal working stage. During the operation, a tape held the fabric article 43 and the rod 44 held the article as shown in FIG. 10. Camera vision was used to detect the types, outlines, and centerlines of the articles. Since the tapes described in the patent were essentially straight, such machine was not suitable for folding fabrics in a freeform manner. Moreover, it does not apply any ironing actions for setting the folds.

Another type of conventional folding machine 10 is for folding large-area fabric materials, typically textile sheets or fabrics directly from a knitting machine. An example of such industrial folding machine is illustrated in FIG. 11. The fabric material was continuously fed by an array of rollers and a sliding guide 24 was moving back and forth to facilitate the folding in a reciprocal manner.

FIG. 12 is another example of making use of oppositely moving transport belts to create fold edges on long fabric materials. However, the folding machine could only vary the lengths between successive folding edges, not the geometries of the fold lines. The fold lines were defined by the guiding rods or edges of conveyer belts which were predefined (mostly straight). The machine was designed to handle sizable fabric materials coming directly out of the production facility and thus not applicable to small and standalone fabric parts.

Yet another type of conventional folding device is shown in FIG. 13, where orthogonal rollers 21, 23 were employed to re-align oriented fabric materials such that the material strength was increased along certain directions. The folding patterns or geometries were defined and fixed by the configuration of the rollers, making it difficult for the folding machine to perform adaptive freeform folding.

Further, there are several patents related to automatic folding of small and standalone fabric components for garment production. For instance, U.S. Pat. No. 5,029,537 describes an apparatus for contoured folding and hemming of garment parts such as pockets, as shown in FIG. 14. The apparatus adopted a clamping die and a flat metal plate which had geometries similar to the shapes of the intended pocket. In the folding process, a piece of pocket ply was put onto a contoured plate and then the clamping die pressed on the pocket ply, leaving some margin of the ply beyond the edge of the plate as shown in FIG. 14. The movable parts of the clamp then conformed to the contoured edges of the plate, forcing the ply to fold downward and then horizontally inward. The folded pocket ply was next transferred to a sewing station for stitching a contoured hem. The shapes of the pocket hem were entirely determined by the shapes of the contoured plate, inhibiting the apparatus from forming pockets of different shapes. In addition, U.S. Pat. No. 5,029,537 describes a folding apparatus presumably limited to folding pockets having a flat bottom or a shallow “V” shape. The folding was prone to generation of uncontrolled formation of pleats whenever a curved fold line was processed, making the apparatus unfavorable for reproducing freeform folding or controlled generation of pleats.

BRIEF SUMMARY OF THE INVENTION

There continues to be a need in the art for improved designs and techniques for a system and methods for automatic adaptive fabric folding.

Embodiments of the subject invention pertain to an adaptive fabric folding system for folding a subject fabric article. The system comprises a turnover device; a fold line adjuster configured to adjust a fold line of the subject fabric article; a pleat generator; and a fold line fixing device. The pleat generator comprises an adjustor adjusting a width of a pleat of the subject fabric article and a fabric feeding device. The turnover device is configured to flip a margin of the subject fabric article delimited by a preset fold line. The fold line adjuster comprises a guiding portion having at least one side aligned with the fold line. The guiding portion may have a shape with a curvature, a straight shape, or any other shape suitable for being aligned with the fold line. The fold line adjuster is configured such that a lateral movement of the guiding portion changes a width of margin of the subject fabric article that engages with a curvature of a surface which can be, for example, a spiral surface of the turnover device to alter the fold line. The pleat generator is configured to create and regulate widths of pleats while moving the subject fabric article. Moreover, the fold line fixing device may comprise a roller configured to flatten the subject fabric article under pressure and/or heat. The adaptive fabric folding system may further comprise a suspension module that comprises platens, columns, and coil springs. The suspension module can be configured to absorb vibrations of the adaptive fabric folding system and assist with leveling of the adaptive fabric folding system when the subject fabric article moves on a working surface.

According to an embodiment of the subject invention, a method for adaptively folding a subject fabric article on a working surface is provided. The method comprises flipping, by a turnover device, a margin of the subject fabric article delimited by a preset fold line; adjusting, by a fold line adjuster, a fold line of the subject fabric article; creating and regulating widths of pleats of the subject fabric article, by a pleat generator, while moving the subject fabric article on the working surface; and flattening, by a fold line fixing device, the subject fabric article simultaneously under pressure and heat. The flipping a margin of the subject fabric article comprises guiding a portion of the subject fabric article and rotating by a curvature of a surface which can be, for example, a spiral surface in such a way that the subject fabric article becomes curled, when the subject fabric article engages a curved surface of the turnover device. The adjusting fold line comprises changing a width of the margin of the subject fabric article that engages with a curvature of a surface which can be, for example, a spiral surface of the turnover device. When the curled part of the subject fabric article is brought under a feeding roller, the curled part the roller is flattened. The creating and regulating widths of pleats comprises when the flipped fabric is brought under the feeding roller, wave-like protrusions are created at wake which are in turn depressed by a flap. The widths of the pleats are regulatable by the level/height of the flap and/or the rotational speed of the feeding roller. The flattening the subject fabric article under pressure or simultaneously under pressure and heat comprises bringing protruded fabric under a roller of the fold line fixing device. The fold line adjuster comprises a guiding portion. The guiding portion has at least one side aligned with the fold line. The guiding portion may have a shape with a curvature, a straight shape, or any other shape suitable for being aligned with the fold line.

In certain embodiment of the subject invention, a robotic fabric folding system is provided, comprising the adaptive fabric folding system as described above; a robot manipulator; and a force sensing device coupling the adaptive fabric folding system to the robot manipulator. The robotic fabric folding system may further comprise an image capturing device for capturing real-time images or videos of motions of the robot manipulator for visualization and/or motion control of the robot manipulator or the adaptive fabric folding system.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic representation of a robotic fabric folding system, according to an embodiment of the subject invention.

FIG. 2 is a schematic representation of an adaptive fabric folding system of the robotic fabric folding system, according to an embodiment of the subject invention.

FIG. 3 is a schematic representation of a first folding process for a rough folding of the fabric, according to an embodiment of the subject invention.

FIG. 4 is a schematic representation of a second folding process for adjusting the fold line, according to an embodiment of the subject invention.

FIG. 5 is a schematic representation of a third folding process for generating and adjusting the pleats, according to an embodiment of the subject invention.

FIG. 6 is a schematic representation of the pleat's width adjusting mechanism through which the widths of the pleats are controllable by (i) the height of a gap behind the roller of the pleat's generator and/or (ii) the rotational speed of the roller, according to an embodiment of the subject invention.

FIG. 7 is a schematic representation of a fourth folding process for fixing the fold and pleats, according to an embodiment of the subject invention.

FIGS. 8a to 8c is schematic representation of fold line fixing device.

FIG. 9 shows images of fabric parts folded by the adaptive fabric folding system, according to an embodiment of the subject invention.

FIG. 10 is a schematic representation of a first conventional folding machine, according to a prior art.

FIG. 11 is a schematic representation of a second conventional folding machine that folds the fabric by back-and-forth movements of a guide, according to a prior art.

FIG. 12 is a schematic representation of a third conventional folding machine that makes use of conveying belts to create fold edges on the fabric, according to a prior art.

FIG. 13 is a schematic representation of a conventional method that aligns oriented fabric materials by folding, according to a prior art.

FIG. 14 is a schematic representation of a conventional pocket folding apparatus, according to a prior art.

DETAILED DISCLOSURE OF THE INVENTION

The embodiments of subject invention show a method and systems for a “F-FOLD” (Free Form FOLDing) for adaptively folding fabrics.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. As used herein, the singular forms “a,” “am,” and “the” are intended to include the plural forms as well as the singular forms, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, steps, operations, elements, and/or components, but do not prelude the presence or addition of one or more other features, steps, operations, elements, components, and/or groups thereof.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one having ordinary skill in the art to which this invention pertains. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present disclosure and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

When the term “about” is used herein, in conjunction with a numerical value, it is understood that the value can be in a range of 90% of the value to 110% of the value, i.e. the value can be +/−10% of the stated value. For example, “about 1 kg” means from 0.90 kg to 1.1 kg.

In describing the invention, it will be understood that a number of techniques and steps are disclosed. Each of these has individual benefits and each can also be used in conjunction with one or more, or in some cases all, of the other disclosed techniques. Accordingly, for the sake of clarity, this description will refrain from repeating every possible combination of the individual steps in an unnecessary fashion. Nevertheless, the specification and claims should be read with the understanding that such combinations are entirely within the scope of the invention and the claims.

When making a garment, fabric parts need to be folded into desired shapes/forms before they can be sewn in place properly. Fabric parts such as pockets or sleeve cuffs require folding prior to hemming or sewing.

Referring to FIG. 1, a robotic fabric folding system 100 is coupled to an adaptive fabric folding system 200 for freeform folding. The adaptive fabric folding system 200 can be configured to mount onto a robot manipulator 300 of the robotic fabric folding system 100, with an optional force sensing device 400 coupling the adaptive fabric folding system 200 to the robot manipulator 300. The adaptive fabric folding system 200 being actuated by the robot manipulator 300, can be precisely maneuvered and positioned with respect to the subject fabric 600 to perform a freeform folding task on the subject fabric 600. The subject fabric 600 may be optionally disposed on a support, for example, a suction stage 700. A camera 500 can be additionally integrated into the robotic folding system 100 for capturing real-time images or videos of motions of the robot manipulator 300 and the adaptive fabric folding system 200 to perform visualization and/or motion control of the robot manipulator 300 and the adaptive fabric folding system 200.

Now referring to FIG. 2, the adaptive fabric folding system 200 can comprise five components including (1) a turnover device 210, (2) a fold line adjuster 220, (3) a pleat generator 230 that comprises a pleat width adjusting mechanism 232 and a fabric feeding mechanism 234, (4) a fold line fixing device 240, and (5) a suspension device 250.

In particular, the turnover device 210 can be configured to flip a margin of the subject fabric delimited by a preset fold line which can be a visible fold line or a virtual fold line. When a visible fold line is in place, the fold line can be detected by a camera vision and the folding operation may be performed along the visible fold line. When a virtual fold line which is not visible is in place, the fold line trajectory can be determined by a position and orientation estimation method, which may be, for example, based on CAD data prepared in advanced and/or vision data captured during actual operations. When the subject fabric engages the curved surface 212 of the turnover device 210, a portion of the subject fabric is guided and rotated by the curvature of the surface 212 which can be, for example, a spiral surface, in such a way that the subject fabric becomes curled as the adaptive fabric folding system 200 advances along the fold line of the subject fabric. A first folding method for a rough folding of the subject fabric is illustrated in FIG. 3.

Moreover, the adaptive fabric folding system 200 can be configured to enable the fold line to be re-adjusted through a method shown in FIG. 4. The fold line adjuster 220 of the adaptive fabric folding system 200 is equipped with a guiding portion having one of its sides aligned with the fold line. The guiding portion may have a shape with a curvature, a straight shape, or any other shape suitable for being aligned with the fold line. The lateral movement of the guiding portion may change the width of the fabric margin that engages with the curvature of the surface 212 which can be for example, a spiral surface, of the turnover device 210, thereby altering the fold line when necessary. Once the curled part of the fabric is brought under a feeding roller 222, the roller flattens the curled part and completes the flipping process.

In the case of a straight fold line, the flipped part of the fabric remains reasonably flat after being pressed by the feeding roller. On the other hand, in the case that the fold line has a curved geometry, some parts of the subject fabric pop up and protrude from the surface of the flipped fabric. The protrusions are herein referred to as “pleats”. The pleat generator 230 of the adaptive fabric folding system 200 can be configured to create and regulate the widths of the pleats while moving the subject fabric through the working stage.

FIG. 5 shows the details of the pleat-generating and feeding method. Once the flipped fabric is brought under the feeding roller, wave-like protrusions are created in the wake which are in turn depressed by a flap. Further, as shown in FIG. 6, the widths of the pleats are controllable by (i) the height of a gap behind the roller of the pleat's generator and/or (ii) the rotational speed of the roller.

Now referring to FIG. 7, further advancement of the pleat generator 230 can bring the protruded fabric under another roller 242 of the fold line fixing device 240. The fold line fixing device 240 is capable of flattening the subject fabric under simultaneous actions of pressure and heat in a fashion similar to ironing, thereby completing the pleats generation process.

As above mentioned, once the curled part of the fabric is brought under a feeding roller 222 and fed by the roller 222 to the pleat generator 230, after pleats are made by the pleat generator 230 in the fabric, the protruded fabric is fed under the fixing roller 242. The fixing roller 242 functions to apply pressure and heat, equivalent to the action of ironing, to set the fold and pleats, if any. Such heating can be provided by an active heating device, e.g., a resistance heater, an induction heater or an infra-red heater, installed with the roller in the manner exemplified in FIG. 8a. In this example, a cylindrical cartridge heater 261 is placed inside a hollow shaft 262 which rotatably supports the roller 242 with ball bearings 263 on both ends. The heat is transferrable from the heater 261 to the roller 242 collectively by conduction, convection and, to a lesser extent, radiation. To improve the heat conductivity, a preferred material for the hollow shaft 262 and the roller 242 is a copper-base alloy such as brass. A temperature regulator 264, such as a bimetal thermostat, may be included in the circuit to control the temperature of the roller 242 to within a desirable temperature range (e.g., from 130 to 200 degrees Celsius for common fabric materials).

In another embodiment, the roller 242 may further incorporate a rotary mechanism which is operable to adjust the angle of the rotation axis of the roller relative to the motion direction of the end-effector or the feeding direction X of the fabric, see FIG. 8b. In the case of some stiffer fabric materials, the portion of fabric before going under the roller 242 may experience a tendency to bend outward due to its intrinsic elasticity, the effect of which may cause the fixed fold to deviate progressively from the intended fold line. To mitigate such positional error, a suitable inclination angle α (e.g., 0-20 degrees) of the roller 242 can be set by the hinged joint 243 such that the subsequent rolling movement will induce a shear force component acting on the fabric that opposes the outward shift of the fabric, thereby maintaining correct positions of the fold. A schematic illustration is provided in FIG. 8c.

The adaptive fabric folding system 200 may further comprise a suspension device 250 constructed with platens, columns and coil springs. The suspension device 250 is configured to absorb vibrations and assist with leveling of the adaptive fabric folding system 200 with respect to the subject fabric disposed on the working stage. As shown in FIG. 8a, the fixing roller 242 is mounted to the suspension mechanism 250 by frame 244. The suspension mechanism 250 may include a mounting plate 251 and an insulating layer 252 for insulating the heat generated from or conducted by the roller 242.

A series of folding experiments are carried out by running the adaptive fabric folding system and method (actuated by human hands instead of a robot manipulator) along the visible or virtual fold lines of different geometries.

FIG. 9 shows images of the experiment results. Three representative samples of fabric parts are processed by the adaptive fabric folding system and methods, where the folded geometries are proven to be consistent with the fold lines. The results demonstrate that the F-FOLD adaptive fabric folding system and methods effectively perform folding tasks on different geometries including, but not limited to, a straight line (on the left of FIG. 9), a continuous curve (in the middle of FIG. 9), and a combination of a straight line and a continuous curve (on the right of FIG. 9). Pleats are generated and set where a curved fold line is present.

As described earlier, the adaptive fabric folding system can be coupled to the robotic fabric folding system to perform automatic fabric folding processes. Herein is an exemplary automatic folding process including following steps:

• • step 1: a pant part is placed on the working stage and a contoured plate (of shapes of the pocket) comes out over the pant part;
  • step 2: a user places a pocket ply on the contoured plate;
  • step 3: a folding system clamps the pocket ply and folds the margin of the ply inwards, and the system then lowers the folded ply onto the pant part and retracts;
  • step 4: after the retraction of the folding system, a fixture such as a metal clamp moves leftwards and presses on the pocket assembly;
  • step 5: the fixture such as a metal clamp drags the assembly rightwards and positions it under a sewing machine;
  • step 6: the sewing needle follows the path defined by the fixture and performs stitching; and
  • step 7: when the sewing is completed, the assembly is removed from the working stage and the steps are repeated for another fabric assembly.

The embodiments of the adaptive fabric folding system and methods of the subject invention provide a number of advantages over the conventional folding devices.

First, the embodiments of the adaptive fabric folding system and methods adopt a continuous guiding surface having a surface of a curvature which can be, for example, a spiral surface, to turn over the edge of the fabric. In contrast, the conventional folding device makes use of a hook mechanism acting on a small portion of the edge one at a time, making the folding action a piecewise process rather than a continuous process.

Second, the folding actions of the embodiments of the adaptive fabric folding system and methods are accomplished by the roller mechanism with heating to provide ironing effect to fix the folds in shapes. In contrast, the conventional folding devices use localized pressing and hammering to set the folded edge with the use of adhesive, imposing a significant limitation to folding fabric materials that are not constructed with or not suitable for the use of adhesives.

Third, the embodiments of the adaptive fabric folding system and methods include the pleat generating/adjusting mechanisms that are crucial for folding fabrics along curved fold-lines, whereas the conventional folding devices do not provide such mechanisms.

Thus, the embodiments of the adaptive fabric folding system and methods of the subject invention enable freeform folding and fixing of garment components prior to sewing.

When being coupled to the robot manipulator as an end-effector, the adaptive fabric folding system and methods are capable of performing automatic folding tasks in place of human workers with much higher degree of accuracy and efficiency.

Further, since the conventional folding approaches require a set of pre-designed fixtures for a particular size/style of garment, mass customization is not feasible. The adaptive fabric folding system and methods of the subject invention, working together with the robotic manipulator, allow customized production of garments of different styles by the same production line.

The adaptive fabric folding system and methods can be applied to folding of a single fabric part of any type along a fold line of variable geometries including straight lines and/or curved lines with a wide range of curvatures.

All patents, patent applications, provisional applications, and publications referred to or cited herein are incorporated by reference in their entirety, including all figures and tables, to the extent they are not inconsistent with the explicit teachings of this specification.

It should be understood that the examples and embodiments described herein are for illustrative purposes only and that various modifications or changes in light thereof will be suggested to persons skilled in the art and are to be included within the spirit and purview of this application and the scope of the appended claims. In addition, any elements or limitations of any invention or embodiment thereof disclosed herein can be combined with any and/or all other elements or limitations (individually or in any combination) or any other invention or embodiment thereof disclosed herein, and all such combinations are contemplated with the scope of the invention without limitation thereto.