System and method for three-dimensional sewing

Abstract

Disclosed is a 3D sewing system and method thereof, the 3D sewing system comprising: a sewing subsystem comprising a needle configured to sew on at least partially overlapping upper and lower fabrics; a fabric feeding subsystem configured to feed each fabric in at least two perpendicular directions; a tension adjusting subsystem configured to apply a required tension in each fabric; and a control subsystem configured to control the fabric feeding subsystem to feed the fabrics according to a predetermined path and to control the tension adjusting subsystem to apply a required tension in one or each fabric.

Description

Technical Field

[0001] This disclosure relates to the apparel industry, specifically to a 3D sewing system and a 3D sewing method. Background Technology

[0002] 3D sewing is a technique that involves stitching curved seams to create a three-dimensional shape in garment products. This technique is essential in the production of various garments, such as suits, jackets, dresses, underwear, and sportswear, where a close fit to the body and freedom of movement are crucial. For example, in T-shirts, the neckline, sleeves, and hem are typical areas that need to be sewn along curved contours so that the resulting shape conforms to the wearer and fits comfortably. Many other fashion accessories, including handbags, footwear, and leather goods, also involve significant 3D sewing operations in their production processes.

[0003] To date, sewing in garment factories remains primarily performed by human workers. While automation is becoming increasingly prevalent in the garment industry, sewing operations that can be effectively automated are generally limited to two-dimensional (2D) sewing, typically involving stitching along pre-formed guides or tracks on a two-dimensional plane using custom-designed jigs and / or fasteners. This approach is less suitable for three-dimensional sewing processes, as such processes require fabric parts or subassemblies to be manipulated frequently in different directions according to the desired three-dimensional geometry. Therefore, it is more common for three-dimensional sewing tasks to be performed by well-trained, skilled human workers. However, this reliance on manual labor limits productivity and increases production costs, making the garment industry vulnerable to labor shortages and rising wages.

[0004] Therefore, there is a need to improve 3D sewing systems and 3D sewing methods. Summary of the Invention

[0005] This invention relates to an automated sewing system for constructing three-dimensional shapes by piecing together fabric pieces with reference to the contours of cut edges.

[0006] In one embodiment, the 3D sewing system includes: (1) a sewing subsystem including a needle configured to sew on at least partially overlapping upper and lower fabric layers; (2) a fabric feeding subsystem configured to feed each fabric layer in at least two vertical directions; (3) a tension adjustment subsystem configured to apply a desired tension in each fabric layer; and (4) a control subsystem configured to control the fabric feeding subsystem to feed the fabric according to a predetermined path and to control the tension adjustment subsystem to apply a desired tension in one or each fabric layer.

[0007] Using the 3D sensing system according to this disclosure, the feed subsystem can feed the fabric along a predetermined path, particularly a curved path, which can maintain a constant distance from the edge of one or more layers of fabric, so that, under the closed-loop control of the control subsystem, the needle can sew the fabric along a path parallel to the fabric edge. Furthermore, through the tension adjustment subsystem, the fabric is straightened, and wrinkles that might otherwise disrupt the sewing operation can be avoided.

[0008] In another embodiment, the sewing system may include: (i) a sewing subsystem for sewing fabric; (ii) a fabric feeding mechanism that may include multiple active omnidirectional wheels with surfaces optimized for frictional contact with the fabric; (iii) an actuation mechanism for rotatable components (including main wheels and auxiliary rollers) driving the omnidirectional wheels; (iv) a worktable assembly that slides to support a target fabric sheet; (v) a barcode-based laser position sensing subsystem for detecting the edge position (or cutting line) of the fabric; and (vi) a control subsystem that provides closed-loop control of the fabric position and tension using the edge position signal and sewing speed, respectively.

[0009] Using the 3D sewing system according to this disclosure, the tension adjustment subsystem and the fabric feeding subsystem can share the omnidirectional wheel and the main feeder, thereby simplifying the structure of the entire system.

[0010] In another embodiment of this disclosure, a 3D sewing method is proposed, comprising: sewing on an upper and lower fabric that at least partially overlap; feeding the upper and lower fabrics along a predetermined path to sew the fabrics together; and applying a desired tension in one or each layer of fabric. Attached Figure Description

[0011] Although the specification concludes with claims that specifically point out and expressly claim protection for what are considered embodiments of the invention, the advantages of the embodiments of the present disclosure can be more readily determined when the description of certain examples of embodiments of the present disclosure is read in conjunction with the accompanying drawings, in which: Figure 1 This is a schematic diagram illustrating a 3D sewing system according to an embodiment of the present disclosure; Figure 2 yes Figure 1 A top view of a 3D sewing system; Figures 3A to 3C This is a schematic diagram showing an example of an omnidirectional wheel; Figure 4 The working principle of an omnidirectional wheel including at least one active auxiliary roller according to the present disclosure is shown; Figure 5 A side view of an active feed subsystem including an omnidirectional wheel with active auxiliary rollers is shown. Figure 6This is a schematic diagram showing the sensing subsystem; Figure 7A and Figure 7B Two possible placement methods for barcodes on the surface of the middle plate, bottom plate, and / or column bed are illustrated; Figure 8 and Figure 9 This is a schematic block diagram illustrating the system architecture and controller of a 3D sewing system; Figure 10 This is a flowchart illustrating the method of feeding the fabric; and Figure 11 This demonstrates how the distance between the fabric cut line and the stitch line can be corrected by controlled rotation of an active omnidirectional wheel. Detailed Implementation

[0012] This document describes example methods, systems, and devices. Any example embodiments or features described herein should not be construed as preferred or advantageous over other embodiments or features. The example embodiments described herein are not intended to be limiting. It will be readily understood that certain aspects of the disclosed systems and methods can be arranged and combined in a variety of different configurations, all of which are contemplated herein.

[0013] Furthermore, the specific arrangements shown in the accompanying drawings should not be considered limiting. It should be understood that other embodiments may include more or fewer portions of each element shown in a given drawing. Additionally, some illustrated elements may be combined or omitted. Moreover, exemplary embodiments may include elements not illustrated in the drawings.

[0014] The technical solutions of this disclosure will be described in detail below with reference to specific embodiments thereof. In the following description and claims, directional terms such as “forward,” “lateral,” “front,” “back,” “left,” “right,” “up,” and “down” are used to clearly describe the invention and enable those skilled in the art to understand the description, but are not intended to be limiting. In the following description and drawings, subsystems or elements for the upper fabric will be indicated by reference numerals with the suffix “U,” those for the lower fabric will be indicated by reference numerals with the suffix “L,” and when it is not necessary to distinguish between those for the upper and lower fabrics, they will be indicated by reference numerals without suffixes.

[0015] According to this disclosure, a 3D sewing machine or system is proposed that can perform three-dimensional (3D) sewing by automatically aligning its seam lines according to the cut edges of a fabric piece, thereby simplifying its control algorithms and methods, as well as the control system. The 3D sewing system according to this disclosure includes: a sewing subsystem configured to sew on a fabric; a feeding subsystem configured to feed the fabric to be sewn in at least two vertical directions (e.g., forward and laterally) under the control of a control system or control module; a sensing subsystem configured to detect the edges of the fabric and provide the detection results to the control system or module; and a control subsystem or module configured to receive the detection results from the sensing system and control the feeding system to feed the fabric.

[0016] In one embodiment, the fabric comprises two pieces of fabric that at least partially overlap and are sewn together along the edges of the two pieces of fabric. The feeding subsystem includes an upper-layer feeding subsystem for feeding the upper layer of fabric and a lower-layer feeding subsystem for feeding the lower layer of fabric. In one embodiment, each feeding subsystem includes at least two drive wheels, one of which is an omnidirectional wheel configured to feed the fabric in two directions, and the other is a feed wheel or main feeder configured to feed the fabric in one of the two directions (referred to as the main feed direction, or forward direction). However, this application is not limited thereto; the main feeder may include a passive roller presser foot and a feed dog that cooperate to feed the fabric forward.

[0017] In one embodiment, the 3D sewing machine or system further includes a tension adjustment subsystem configured to apply the required tension in at least one layer of fabric (preferably two layers), which is important for proper stitch formation and wrinkle elimination in the fabric. Therefore, the tension adjustment subsystem includes an upper-layer tension adjustment subsystem for the upper fabric and a lower-layer tension adjustment subsystem for the lower fabric; hereinafter, when there is no need to distinguish between the upper and lower layer tension adjustment subsystems, they will be collectively referred to as the tension adjustment subsystem. The tension adjustment subsystem may share an omnidirectional wheel with the feed subsystem, specifically, the active auxiliary roller and the main feed of the omnidirectional wheel; however, this disclosure is not limited thereto, and a separate tension adjustment subsystem may be provided.

[0018] In a preferred embodiment, the omnidirectional wheel includes a main wheel body rotatable along a main rotation axis, and a plurality of active rim elements (or auxiliary rollers) arranged circumferentially around the main wheel body and rotatable along an axis inclined relative to the main rotation axis. Thus, the rotation of the main wheel body feeds the fabric in one direction (e.g., laterally), while the rotation of the rim elements feeds the fabric in a direction preferably perpendicular to the feeding direction of the main wheel body (e.g., forward). Tension can be applied by the main feeder and the rim elements or auxiliary rollers of the omnidirectional wheel.

[0019] In one embodiment, the sensing subsystem includes an upper sensing subsystem for an upper layer fabric and a lower sensing subsystem for a lower layer fabric. Each of the upper and lower sensing subsystems includes a sensor that detects the edge of the fabric using a marker. In a preferred embodiment, the sensor is a laser sensor and the marker is a barcode. However, this disclosure is not limited thereto.

[0020] The 3D sewing machine or system will be described in detail below with reference to the accompanying drawings.

[0021] Figure 1 This is a schematic diagram illustrating a 3D sewing system according to an embodiment of the present disclosure. Figure 2 yes Figure 1 A top-down view of a 3D sewing system. Figure 1 and Figure 2 The reference directions for X, Y, and Z are defined and illustrated. These directions provide a standardized framework for referencing spatial directions within the context of a given description. Where + or - is not specified, any X / Y / Z direction mentioned in the text carries both + and - meanings. For example, the term "X direction" includes both X(+) and X(-) directions.

[0022] like Figure 1 As shown, the system includes a sewing machine characterized by a raised post bed 10 (also called a post head) below the needle 20. Two pieces of cut fabric (not in...) Figure 1 and Figure 2 (As shown in the diagram) is loaded onto a worktable assembly comprising a base plate 30 and a middle plate 40, where the fabric is slidably supported in the XY plane. The fabric sheet located on top of the middle plate 40 is referred to as the upper fabric (UF), while the fabric sheet located between the middle plate 40 and the base plate 30 is referred to as the lower fabric (LF). The base plate 30 of the worktable assembly is preferably flush with the top surface of the post bed 10.

[0023] Feed subsystem

[0024] The sewing machine also includes a feed subsystem for feeding the fabric, which includes an upper feed subsystem for upper fabric (UF) and a lower feed subsystem for lower fabric (LF). The upper feed subsystem and the lower feed subsystem are generally mirror-symmetrical about each other around the post bed. Therefore, in the following description, only the upper feed subsystem will be described, and the same applies to the lower feed subsystem. When it is not necessary to distinguish between the upper feed subsystem and the lower feed subsystem, they will also be referred to as the feed subsystem.

[0025] The feed subsystem near needle 20 includes, for example, (i) a roller presser foot or (ii) a wheel feeder. A roller presser foot is a passive roller that operates in conjunction with the sewing machine's built-in feed dogs. During sewing, the feed dogs move the fabric forward, and the roller presser foot presses against the fabric to hold it in place as it advances. Alternatively, a wheel feeder is an active roller device that operates synchronously with needle 20 to feed the fabric forward. Where a wheel feeder is present, feed dogs are typically not required. Figure 1 As shown, in a preferred embodiment of this disclosure, the feed subsystem includes an active roller (main feeder) 80; however, this application is not limited to this, and a passive roller presser foot and feed dog may also be used. For simplicity, the roller assembly near the needle 20 is referred to hereinafter as the "main feeder". The main feeder 80 feeds the fabric in the positive Y direction (hereinafter also referred to as the forward direction).

[0026] In conjunction with the main feeder 80, one or more active omnidirectional wheel feeders 50U, 50L (or omnidirectional wheels) are provided. During sewing, the main feeder 80 provides one traction point on the fabric, and the omnidirectional wheels 50U, 50L provide another traction point, thereby allowing the required tension to be applied in the upper and lower layers of fabric. The post bed 10 and the machine body are configured to provide mechanical support to the table assembly.

[0027] Once positioned, the upper and lower fabric layers can be manipulated in multiple directions by the active feeding subsystem. For example... Figure 2 As shown, the omnidirectional wheels 50 are located after the needle drop point, preferably such that their main rotation axes MA are located within a region d, which is defined by a line relatively enclosed by (i) the fabric contact point of the main feeder 80 and (ii) the needle drop point O, extending in the negative Y direction. The omnidirectional wheels of the upper and lower feed subsystems make physical contact with the target fabric and are spring-loaded to apply pressure to the fabric.

[0028] Reference Figures 3A to 3C The omnidirectional wheel 50 is described, with three examples of the omnidirectional wheel 50 shown.

[0029] like Figure 3A As shown, the omnidirectional wheel 50 is a Mecanum wheel, comprising a main wheel body 51 and multiple barrel-shaped rim elements 52 rotatably mounted on the circumference of the wheel body 51. A distinctive feature of these barrel-shaped rollers 52 is that their axes of rotation are arranged obliquely, typically at 45 degrees to the wide plane of the wheel 50 and to the axle of the wheel 50. Therefore, rotation of the main wheel body 51 feeds the fabric in a first direction, while rotation of the rim elements or auxiliary rollers 52 feeds the fabric in a second direction perpendicular to the first direction.

[0030] like Figure 3BAs shown, a second design of the omnidirectional wheel 50' is illustrated. The omnidirectional wheel 50' includes a main wheel body 51' and a plurality of cylindrical rotatable rim elements or auxiliary rollers 52'. Each rim element has a rotation axis parallel to a wide plane of the main wheel body 51' and at a 90-degree angle to the rotation axis of the main wheel body 51'. The rotation of the main wheel body 51' feeds the fabric in a first direction, and the rotation of the rim elements 52' feeds the fabric in a second direction perpendicular to the first direction. Figure 3A and Figure 3B The omnidirectional wheels shown have a geometric feature in that their outer periphery contains grooves and deviates from a circle.

[0031] Figure 3C Another example of a 50” omnidirectional wheel design is shown. Figure 3C As shown, the omnidirectional wheel includes a main wheel body 51” and multiple barrel-shaped rotatable rim elements or auxiliary rollers 52”, each with an outer edge that outlines a circular arc. By using such an omnidirectional wheel with a properly designed wheel frame, a configuration can be formed such that the overall circumference of the wheel outlines a circular profile, as... Figure 3C As shown.

[0032] Figure 4 This illustrates the working principle of the omnidirectional wheel 50. The omnidirectional wheel 50' can be as follows: Figure 3B The omnidirectional wheel shown includes a main wheel body 51' and an active rim element 52' (or active auxiliary roller) capable of controlled rotation. This active omnidirectional wheel has a mechanism for transmitting power in the polar direction through engagement. This mechanism consists of three elements: a circular track 53 whose cross-sectional shape rotates along the polar direction, a slider 54 that slides along the circular cross-sectional shape, and a slit 55 on the slider to avoid interference with the spokes 59 of the fixed track. Here, through inputs from the rim element, which rotates independently by, for example, a motor (not shown), and the main wheel body 51', the active omnidirectional wheel provides rotational motion in two independent directions: one around the axle of the main wheel body 51' and the other around the axle of the auxiliary roller 52', thus generating two degrees of freedom of movement. Further details of the omnidirectional wheel 50' can be found in previously published patent applications, such as CN3064626A1, US3789947, US10589950B2, and US20230009594A1, the contents of which are incorporated herein by reference in their entirety.

[0033] While the above description of an omnidirectional wheel design with an active assist roller is provided as an example, it should be understood that the invention covers other variations and configurations of omnidirectional wheels, as long as they incorporate the essential features of an active assist roller. The specific embodiments mentioned above are intended to illustrate the concept and should not be construed as limiting the scope of the invention.

[0034] Figure 5 A side view of an active feed subsystem including an omnidirectional wheel 50 with active auxiliary rollers is shown, detailing the stacking order of the fabric sheet UF / LF, middle plate 40, bottom plate 30, and omnidirectional wheels 50U and 50L. Figure 5 As shown, the surface of the active omnidirectional roller includes multiple corrugated features 56 to provide an anti-slip surface texture. These features enhance surface friction and thus generate higher traction when engaging the fabric. Suitable surface materials for the active auxiliary rollers include, but are not limited to, elastomeric materials (such as rubber and silicone) and sponge materials. Each of the upper and lower omnidirectional rollers is driven by two motors 57U, 57L and further connected to tensioners 58U, 58L actuated by solenoids (upper / lower actuators) (not shown). Movement of the solenoids can activate linkages connecting the corresponding omnidirectional rollers 50U, 50L, allowing the omnidirectional rollers to press against the fabric with the desired normal force.

[0035] Once the upper and lower fabrics UF / LF are placed between the center plate 40 and the corresponding omnidirectional rollers 50U, 50L, these fabrics can be manipulated independently on and against the center plate 40. The feed action of the omnidirectional rollers 50U, 50L is dual. First, by rotating the omnidirectional rollers 50U, 50L about their main axle in the Y direction, the fabric at the joint can be fed laterally in the X direction and rotated around the needle, which serves as the approximate center of rotation for the fabric. Second, by rotating the auxiliary rollers of the omnidirectional rollers 50U, 50L to generate a tangential motion parallel to the Y direction, the joint of the fabric can be stretched relative to the needle and the main feeder 80, thereby generating tension in the fabric through antagonistic action. The ability to apply tension to the fabric during sewing is crucial for proper stitch formation and wrinkle elimination. The center plate is designed with a flat, smooth surface finish on both sides to facilitate low-friction sliding of the fabric sheet.

[0036] Tension regulation subsystem

[0037] As described above, this disclosure provides a tension adjustment subsystem for each of the upper fabric UF and the lower fabric LF. The tension adjustment subsystem of the upper fabric UF will be described as an example, and it will be understood that the same applies to the lower fabric LF.

[0038] The tension adjustment subsystem includes a main feeder 80 and an omnidirectional wheel 50, specifically, an active auxiliary roller for the omnidirectional wheel. When the fabric is fed by the main feeder 80, the auxiliary roller can rotate at a speed lower than the feed speed of the main feeder 80; in other words, there is a speed difference between the linear velocity of the main feeder 80 and the linear velocity of the auxiliary roller, thereby generating tension in the fabric. It can be understood that the auxiliary roller can be stationary or even rotate in the opposite direction to generate the desired tension in the fabric.

[0039] Preferably, the auxiliary roller of the omnidirectional wheel 50 is shaped to maximize physical contact and thus maximize traction on the fabric; therefore, the active auxiliary roller of the omnidirectional wheel 50 has a curvature that substantially conforms to the circumference of the main wheel body. Alternatively or additionally, the tension in the fabric can be altered by controlling the pressure applied to the fabric by the omnidirectional wheel 50 using, for example, a solenoid for the upper fabric UF and the lower fabric LF.

[0040] In addition, the auxiliary rollers can be formed of a flexible, soft material (such as rubber or textiles), or the surface of the auxiliary rollers can be coated with such a material. Alternatively, a friction-increasing coating or roughening treatment can be applied to the surface of the auxiliary rollers.

[0041] The structure of the entire system can be simplified by sharing the main feeder 80 and the omnidirectional wheel 50 between the feed subsystem and the tension adjustment subsystem.

[0042] However, this disclosure is not limited thereto, and a separate tension application or adjustment subsystem may also be incorporated. Furthermore, a tension sensor may be provided to sense the tension in the fabric and send a signal representing the tension in the fabric to a controller (described later), which adjusts the speed of the auxiliary rollers or the pressure of the solenoid at least in part based on the signal received from the tension sensor to apply the desired tension in the fabric.

[0043] Position sensing subsystem

[0044] The 3D sewing system also includes a sensing subsystem 70 to detect the edge positions of the upper and lower fabric layers. For example... Figure 6 As shown, this illustrates a preferred embodiment of a sensing subsystem including optical sensors 71 that detect the positions of the edges of upper and lower fabric layers. Each sensor includes a laser source 72 configured to generate a laser beam, a scanning mechanism 73 configured to scan the laser towards the fabric and a mark 74 (e.g., a barcode), and a detector (e.g., a photodiode) configured to receive the laser reflected from the fabric and the barcode. Thus, the sensor 71 performs reflective laser sensing with reference to the barcode. The barcode can be printed on tape attached to a stationary surface. Specifically, as... Figure 6 As shown, a laser source scans along the X-direction, and a photodiode 75 detects the light signal reflected from the surface containing the barcode. A piece of fabric is positioned such that one of its cut edges overlaps with a portion of the barcode. The barcode consists of black and white bars of equal width, and the laser reads the number of those bars not obscured by the fabric to determine the position of the fabric edge. The width of the bars in the barcode can be changed or reduced to improve sensing resolution. Using the sensing subsystem 70 according to this disclosure, it is not necessary to precisely position or calibrate the laser source 72 or photodiode 75 for the fabric, and the structure of the sensing subsystem 70 is simplified.

[0045] Marker 74 can be printed on various media such as paper and fixed in different positions on the sewing system, depending on the size of the fabric piece and the mounting method of the laser sensor. For example... Figure 1 As shown, two sensing subsystems 70U and 70L, including laser sensors, are located above and below the worktable assembly, respectively, to detect the edge positions of the upper and lower fabric layers. In another embodiment, both laser sensors are mounted above the worktable assembly to detect the target fabric.

[0046] Figure 7A and Figure 7B Two possible placement methods of barcodes 74U and 74L on the surfaces of the middle plate 40, bottom plate 30, and / or post bed 10 are illustrated, where the markings (barcodes 74U and 74L) can be read by a laser sensor placed above the fabric. The positions of needle 20, main feeder 80, and omnidirectional wheel feeder are also shown in the figure. Note that the position of the lower omnidirectional wheel has been slightly offset for clarity. Figure 7A As shown, the barcode used to measure the position of the upper fabric layer can be placed on the far edge of the middle plate 40, while the barcode for the lower fabric layer is placed on the bottom plate 30. A characteristic of this arrangement is that one of the barcodes (but not both) may be located outside the area of ​​the middle plate 40. Figure 7B In another arrangement shown, barcodes 74U and 74L are both located within the inner area of ​​the middle plate 40. Barcode 74U, used to measure the position of the upper fabric layer, can be placed on top of the middle plate 40, while barcode 74L, used for the lower fabric layer, is placed on the bottom plate 30 and exposed to the laser through an opening in the middle plate 40. The actual arrangement of barcode 74L can be one or a combination of the above options. If smaller fabric pieces are involved, barcode 74L can also be placed on the post bed instead of the bottom plate 30; there are no limitations on this.

[0047] Although laser sensors and barcodes are used to sense the edges of fabric in the above description, this application is not limited thereto. Other sensing subsystems, such as magnetic sensing subsystems, sensing subsystems applying the Hall effect, etc., can be envisioned after reading the teachings of this disclosure.

[0048] Control subsystems and methods

[0049] Figure 8 and Figure 9 A schematic block diagram illustrating the system architecture and controller of the 3D sewing system is shown. The control system of the present invention has two main functions, specifically (i) fabric position control via lateral feed, and (ii) tension control.

[0050] like Figure 8 and Figure 9As shown, the control subsystem includes a control unit 81 configured to receive sensing results from the sensing subsystem 70 and send signals to the motors driving the upper and lower omnidirectional wheels, respectively. Furthermore, the control subsystem may also include a sewing machine controller 82 configured to control the sewing machine to sew on the fabric. The sewing machine controller 82 can control the speed of the main feeder 80 to feed the upper and lower layers of fabric forward, and can also control the needle to sew. The control unit 81 and the sewing machine controller 82 can communicate with each other. Although in Figure 8 and Figure 9 In this disclosure, control unit 81 and sewing machine controller 82 are shown as two separate units, but this disclosure is not limited thereto; these two units 81 and 82 can be integrally formed. Control unit 81 and / or sewing machine controller 82 can be implemented by general-purpose ICs, ASICs, or even discrete electronic components, and this disclosure does not limit this. Control unit 81 and / or sewing machine controller 82 can also be embodied as a processor including a CPU, memory for storing programs, data received from sensing systems or the like, and I / O interfaces for communicating with external peripheral devices.

[0051] To begin sewing, the sewing machine controller 82 and / or control unit 81 can control the main feeder 80 and / or omnidirectional wheel 50 to advance the upper and lower layers of fabric at a predetermined speed, and control the needle 20 to sew.

[0052] This system can operatively stitch upper and lower fabric pieces together according to the contour of the cut edge (e.g., a curved edge). In doing so, the stitching can be controlled to follow a path parallel to the cut line, i.e., by maintaining a constant spacing relative to the cut edge, or alternatively, along a path with a pre-programmed variable spacing relative to the edge. Figure 10 An exemplary control flowchart is illustrated, which maintains a predetermined distance (gap) between the needle and the respective edges of the upper and lower fabric pieces.

[0053] like Figure 10 As shown, the control unit 81 receives signals from the upper and lower sensing subsystems indicating the number of strips not covered by the fabric, thus revealing the position of the fabric edge. The number of strips in the appropriate fabric position is pre-recorded, and feedback is provided based on deviations from this number. Based on the feedback signal, the rotation of the omnidirectional wheel 50 around its Y-axis is activated to bring the corresponding fabric edge to a predetermined position in the lateral direction (X direction). Classical PID control can be used as an example of a feedback control algorithm; however, this disclosure is not limited thereto, and other control algorithms, such as fuzzy control algorithms or other modern controls based on precise models, are equally applicable.

[0054] If there is an offset in the XY plane between the barcode and the needle drop point (roughly the center of rotation of the fabric), the stitch may deviate from the intended path, depending particularly on the y-component of this offset, see [reference needed]. Figure 11 This error can be mitigated by controlling the rotation of the active omnidirectional wheel 50, or more precisely, the main wheel body, around its Y-axis to shift the fabric in the X direction, thereby introducing a correction for the distance between the fabric cut line and the seam line.

[0055] For tension control, an appropriate antagonistic force is applied between the fabric area defined by the main feeder 80 (near the needle) and the omnidirectional roller 50 to straighten the fabric and prevent wrinkles. This force can originate from the kinetic friction (or sliding friction) between the auxiliary roller of the omnidirectional roller 50 and the engaged fabric. For elastic soft materials like rubber or textiles, the coefficient of sliding friction (COSF) between two surfaces depends on the surface area, the normal reaction force, and / or the sliding speed. It is believed that the COSF increases with the sliding speed when an elastic soft material slides on a smooth surface. Therefore, the tension in the fabric can be altered by controlling the rotational speed of the rim element or auxiliary roller of the omnidirectional roller 50. Preferably, the auxiliary roller of the omnidirectional roller 50 is shaped to maximize physical contact and thus maximize traction on the fabric; therefore, the active auxiliary roller of the omnidirectional roller 50 has a curvature that substantially conforms to the circumference of the main roller body. Alternatively or additionally, the tension in the fabric can be altered by controlling the pressure applied to the fabric by the omnidirectional roller 50.

[0056] Given the forward feed velocity Vf of the fabric and the tangential velocity Vsr of the auxiliary roller, an antagonistic effect can be established in principle as long as Vsr < Vf when measured along the positive Y direction. The value of the rotational velocity Vsr can vary from below Vf to zero, and from zero to negative values ​​(i.e., reverse rotation), thereby generating a variable range of frictional forces and the resulting tension on / in the fabric.

[0057] The forward feed speed Vf of the fabric is primarily determined by the main feeder 80 of the sewing machine. Once the sewing speed is recorded by the sewing machine controller, the controller outputs a speed control signal to the corresponding motor and changes Vsr accordingly. Depending on the type and characteristics of the fabric to be sewn, the straightening effect on the fabric can be determined in advance through experiments, or changed in real time via the speed selector of the auxiliary roller of the omnidirectional wheel 50. Alternatively, a tension sensing mechanism can be added to detect the tension in the fabric and send a signal representing that tension to the control unit, which then controls the speed of the auxiliary roller of the omnidirectional wheel 50 according to a predetermined value to control or change the tension of the fabric.

[0058] This disclosure is not limited to the specific embodiments described herein, which are intended as illustrative of various aspects. It will be apparent to those skilled in the art that many modifications and variations can be made without departing from its spirit and scope. In addition to those listed herein, functionally equivalent methods and apparatuses within the scope of this disclosure will become apparent to those skilled in the art from the foregoing description. Such modifications and variations are intended to fall within the scope of the appended claims.

[0059] The detailed description above, with reference to the accompanying drawings, illustrates various features and functions of the disclosed systems, devices, and methods. In the drawings, like symbols generally identify like parts unless the context otherwise requires. The exemplary embodiments described herein and in the figures are not intended to be limiting. Other embodiments may be utilized, and other changes may be made, without departing from the spirit or scope of the subject matter presented herein. It will be readily understood that the aspects of this disclosure, as generally described herein and illustrated in the accompanying drawings, can be arranged, replaced, combined, separated, and designed in a variety of different configurations, all of which are expressly contemplated herein.

[0060] A block representing information processing may correspond to circuitry configurable to perform a specific logical function of the methods or techniques described herein. Alternatively or additionally, a block representing information processing may correspond to a module, segment, or portion of program code (including associated data). Program code may include one or more instructions executable by a processor to implement a specific logical function or action in the method or technique. Program code and / or associated data may be stored on any type of computer-readable medium, such as storage devices including disks or hard disks or other storage media.

[0061] The specific arrangements shown in the figures should not be considered limiting. It should be understood that other embodiments may include more or fewer elements than each shown in a given figure. Furthermore, some illustrated elements may be combined or omitted. Moreover, an exemplary embodiment may include elements not shown in the figures.

[0062] While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The aspects and embodiments disclosed herein are for illustrative purposes only and are not intended to be limiting; the true scope is indicated by the following claims.

Claims

1. A 3D sewing system, comprising: A sewing subsystem includes a needle configured to sew on at least partially overlapping upper and lower fabric layers; A fabric feeding subsystem is configured to feed each layer of fabric in at least two vertical directions; A tension conditioning subsystem is configured to apply the required tension in each layer of fabric; as well as The control subsystem is configured to control the fabric feeding subsystem to feed the fabric according to a predetermined path and to control the tension adjustment subsystem to apply the required tension in one layer or each layer of fabric.

2. The 3D sewing system of claim 1 further includes a sensing subsystem configured to detect the edge position of each layer of fabric and send a signal representing the position to the control subsystem, wherein the control subsystem is further configured to control the fabric feeding subsystem to feed the fabric according to the position sensed by the sensing subsystem.

3. The 3D sewing system according to claim 1 or 2, wherein the predetermined path is a curved path.

4. The 3D sewing system according to claim 3, wherein, The curved path maintains a constant distance from the edge of one or each layer of fabric; or The curved path has a variable distance from the edge of one or each layer of fabric.

5. The 3D sewing system according to any one of claims 1 to 4, wherein the fabric feeding subsystem includes a main feeder for feeding an upper fabric and a lower fabric in a first direction; An upper omnidirectional wheel configured to feed the upper fabric in a first direction and in a second direction perpendicular to the first direction; and A lower omnidirectional wheel is configured to feed the lower fabric in a first direction and a second direction.

6. The 3D sewing system of claim 5, wherein each omnidirectional wheel includes a main wheel body and a plurality of active auxiliary rollers, the main wheel body rotating about a rotation axis parallel to a first direction to feed fabric in a second direction, the active auxiliary rollers being rotatably mounted around the circumference of the main wheel body, and the rotation of the active auxiliary rollers propelling the fabric along the first direction.

7. The 3D sewing system according to claim 6, wherein the plurality of active auxiliary rollers have a curvature that substantially conforms to the circumference of the main roller body.

8. The 3D sewing system according to claim 6 or 7, wherein the surface of the auxiliary roller is textured or roughened; and / or the auxiliary roller is coated or formed of an elastic soft material, such as rubber or textile.

9. The 3D sewing system according to any one of claims 6 to 8, wherein the rotating axis is located in a region defined by a line stretched between (i) the fabric contact point of the main feeder and (ii) the needle drop point on the fabric, which are opposite each other in a first direction, and preferably, the rotating axis extends through the needle drop point.

10. The 3D sewing system according to any one of claims 5-9, wherein the tension adjustment subsystem comprises at least a main feeder, an upper omnidirectional wheel and a lower omnidirectional wheel, particularly an active auxiliary roller in the upper omnidirectional wheel and an active auxiliary roller in the lower omnidirectional wheel, wherein tension is applied to the fabric by the speed difference between the main feeder and the auxiliary roller.

11. The 3D sewing system of claim 10, further comprising a tension detection subsystem configured to detect tension in a fabric and send a signal representing the tension in the fabric to a control subsystem, the control subsystem being further configured to change the rotational speed of an auxiliary roller based on the signal received from the tension detection subsystem.

12. The 3D sewing system of claim 10 or 11, further comprising a solenoid to be activated to place an omnidirectional wheel onto the fabric, wherein the control subsystem is further configured to drive the solenoid to change the pressure applied by the omnidirectional wheel onto the fabric, thereby changing the tension in the fabric.

13. The 3D sewing system according to any one of claims 2-12, wherein the sensing subsystem comprises at least an upper sensing subsystem for an upper fabric and a lower sensing subsystem for a lower fabric, each of the upper and lower sensing subsystems comprising a sensor and a marker, the sensor being configured to detect the position of the fabric edge relative to the marker.

14. The 3D sewing system of claim 13, wherein the sensor is a laser sensor and the marking is a barcode, the sensor being configured to detect the number of strips in the barcode that are not covered by fabric.

15. The 3D sewing system of claim 14, wherein the barcode can be attached to or printed on the work surface on which the fabric is placed.

16. The 3D sewing system of claim 14 or 15, wherein the control subsystem is configured to receive a signal representing the number of strips from a sensor, compare the detected number with a predetermined number, and control an omnidirectional wheel to feed the fabric in a second direction based on the error between the detected number and the predetermined number.

17. A 3D sewing method using a 3D sewing system according to any one of claims 1-16, comprising: Sewing is performed on an upper and lower layer of fabric that at least partially overlap; Feed the upper and lower layers of fabric along a predetermined path to sew the fabrics together; as well as Apply the required tension to one or each layer of fabric.

18. The 3D sewing method of claim 17, wherein feeding each of the upper and lower fabric layers comprises: Feed each of the upper and lower layers of fabric in the first direction; as well as Each layer of fabric is fed in a second direction perpendicular to the first direction so as to feed the fabric along a curved path.

19. The 3D sewing method according to claim 17 or 18, wherein feeding each of the upper and lower fabric layers comprises: Sensing the position of the fabric edge; Compare the detected edge locations with the predetermined locations; Adjust the feed rate in the second direction based on the comparison results.

20. The 3D sewing method according to claim 19, wherein sensing the position of the fabric edge includes: Place a barcode on the work surface where the fabric is placed; Detect the number of bars in a barcode that are not covered by fabric.

21. The 3D sewing method according to any one of claims 17 to 20, wherein applying the desired tension in one or each layer of fabric comprises: Adjust the speed difference between the main feeder and the auxiliary rollers of the omnidirectional wheel.

22. The 3D sewing method according to any one of claims 17-21, wherein applying the desired tension in one or each layer of fabric comprises: Adjust the pressure applied to the fabric by the omnidirectional wheel.

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