Automatic sewing machines and their curved sewing methods

Abstract

This invention provides an automatic sewing machine and its curve sewing method. The automatic sewing machine includes a robotic arm module, a sewing module, a fabric feeding module, and a control module. The robotic arm module moves the fabric in the sewing plane. The sewing module sews the fabric. The fabric feeding module delivers the fabric to the sewing module along the feeding direction. The control module acquires the sewing pattern of the fabric, performs path conversion on the sewing pattern to obtain a sewing path with multiple sewing points, and controls the robotic arm module to move the fabric based on the multiple sewing points so that the multiple sewing points pass through the sewing module along the feeding direction. This invention enables fully automatic curve sewing on an automatic sewing machine.

Description

Technical Field

[0001] This invention relates to sewing machines and sewing methods, and particularly to an automatic sewing machine and a curved sewing method. Background Technology

[0002] Existing automatic sewing machines, such as overlock machines, can only perform straight-line sewing due to their linear feeding method. They cannot perform fully automatic curved sewing, such as corner sewing and rounded corner sewing.

[0003] Specifically, when performing curved stitching (such as curved seam stitching), existing automatic sewing machines require a professional tailor to align the fabric to the intended sewing position and slowly feed it into the machine. In this way, through the tailor's skillful patchwork technique, curved stitching can be achieved on an automatic sewing machine.

[0004] However, the aforementioned curved sewing method is not only time-consuming and labor-intensive, but its sewing quality is also highly dependent on the tailor's patchwork skills, which makes the cost of curved sewing too high and the sewing quality unstable.

[0005] Therefore, the existing automatic sewing machines have the above-mentioned problems with curve sewing, and there is an urgent need for a more effective solution. Summary of the Invention

[0006] The main objective of this invention is to provide an automatic sewing machine and a curved sewing method, which can automatically move the fabric so that the sewing point of the fabric is fed into the automatic sewing machine along a straight line.

[0007] In one embodiment, the automatic sewing machine with curved sewing function includes:

[0008] A robotic arm module for moving a piece of fabric on a sewing plane;

[0009] A sewing module for sewing the fabric;

[0010] A fabric feeding module for feeding the fabric to the sewing module along a feeding direction of the sewing plane; and

[0011] A control module, electrically connected to the robotic arm module, the fabric feeding module, and the sewing module, is configured to acquire a sewing pattern of the fabric, perform a path conversion on the sewing pattern to obtain a sewing path including multiple sewing points, and control the robotic arm module to move the fabric based on the multiple sewing points so that the multiple sewing points pass through the sewing module along the fabric feeding direction.

[0012] As described above, the plurality of sewing points have a fixed seam spacing;

[0013] The control module includes a discrete processing module, which is configured to divide the curve into multiple discrete line segments and perform linear interpolation on the multiple discrete line segments to obtain the multiple sewing points corresponding to the multiple discrete line segments. The length of each discrete line segment is not greater than the fixed seam distance.

[0014] As described above, the control module includes a motion control module configured to calculate a sewing vector of the plurality of sewing points, and determine a motion vector or a motion coordinate of the robotic arm module based on at least one of a preset seam distance, a preset sewing speed and a preset needle drop interval and the sewing vector, and control the movement of the robotic arm module based on the motion vector or the motion coordinate so that the sewing vector is parallel to the fabric feeding direction.

[0015] As described above, the movement vector is a velocity vector and includes a first velocity component and a second velocity component, wherein the first velocity component is parallel to the fabric feeding direction.

[0016] The motion control module is configured to control the movement of the robotic arm module based on the first velocity component and the second velocity component, so that the sewing vector of the multiple sewing points is parallel to the fabric feeding direction when the multiple sewing points pass through the sewing module.

[0017] As described above, the movement coordinates are the destination coordinates of the robotic arm module;

[0018] The motion control module is configured to control the robotic arm module to move to the motion coordinate, so that when the multiple sewing points pass through the sewing module, the sewing vector of the multiple sewing points is parallel to the fabric feeding direction.

[0019] As described above, it further includes a template for fixing the fabric, the robotic arm module is connected to the template, and the fabric is translated and rotated on the sewing plane by moving the template.

[0020] As described above, it further includes an image capturing module for capturing a resulting image of the fabric;

[0021] The control module includes a correction processing module, which is configured to correct the movement of the robotic arm module based on the offset when the offset of the plurality of sewing points in the detected result image meets a correction condition.

[0022] In one embodiment, the curved sewing method includes the following steps:

[0023] a) Obtain a sewing pattern for a piece of fabric;

[0024] b) Perform a path transformation on the sewing pattern to obtain a sewing path corresponding to the sewing pattern, wherein the sewing path includes multiple sewing points;

[0025] c) In a sewing program, a fabric feeding module is controlled to feed the fabric to a sewing module along a feeding direction on a sewing plane, and the sewing module is controlled to sew the fabric; and

[0026] d) In the sewing process, a robotic arm module is controlled to move the fabric on a sewing plane based on the multiple sewing points so that the multiple sewing points pass through the sewing module along the fabric feeding direction;

[0027] This path transformation includes:

[0028] e) Perform a discretization transformation on a curve of the sewing pattern to obtain the plurality of sewing points arranged along the curve.

[0029] As described above, the plurality of sewing points have a fixed seam spacing;

[0030] The discretization transformation includes:

[0031] f1) Divide the curve into multiple discrete line segments, wherein the length of each discrete line segment is no greater than the fixed seam spacing; and

[0032] f2) Perform linear interpolation on the multiple discrete line segments to obtain the multiple stitching points corresponding to the multiple discrete line segments.

[0033] As described above, step d) includes:

[0034] d1) Calculate a sewing vector for the multiple sewing points;

[0035] d2) A movement vector or a movement coordinate of the robotic arm module is determined based on at least one of a preset seam spacing, a preset seam speed, and a preset needle insertion interval, along with the sewing vector; and

[0036] d3) Control the movement of the robotic arm module based on the movement vector or the movement coordinate to make the sewing vector parallel to the fabric feeding direction.

[0037] As described above, the movement vector is a velocity vector and includes a first velocity component and an angular velocity component, wherein the first velocity component is parallel to the fabric feeding direction.

[0038] In step d3), the movement of the robotic arm module is controlled based on the first velocity component and the angular velocity component, so that the sewing vector of the multiple sewing points is parallel to the fabric feeding direction when the multiple sewing points pass through the sewing module.

[0039] As described above, the movement coordinates are the destination coordinates of the robotic arm module;

[0040] In step d3), the robotic arm module is controlled to move to the moving coordinate so that the sewing vector of the multiple sewing points is parallel to the fabric feeding direction when the multiple sewing points pass through the sewing module.

[0041] As described above, step d) involves controlling the robotic arm module to move a template used to fix the fabric, thereby translating and rotating the fabric on the sewing plane.

[0042] As mentioned above, this further includes:

[0043] g1) In this sewing process, an image capture module captures a result image; and

[0044] g2) When the offset of one of the multiple sewing points in the detected result image meets a correction condition, the movement of the robotic arm module is corrected based on the offset.

[0045] This invention enables fully automatic curved sewing on automatic sewing machines.

[0046] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the present invention. Attached Figure Description

[0047] Figure 1 This is a structural diagram of an automatic sewing machine according to an embodiment of the present invention;

[0048] Figure 2 This is a structural diagram of an automatic sewing machine according to an embodiment of the present invention;

[0049] Figure 3 This is an architecture diagram of a control module according to an embodiment of the present invention;

[0050] Figure 4 This is a schematic diagram of an automatic sewing machine according to an embodiment of the present invention;

[0051] Figure 5 This is a schematic diagram of an automatic sewing machine according to an embodiment of the present invention;

[0052] Figure 6 This is a schematic diagram of an automatic sewing machine according to an embodiment of the present invention;

[0053] Figure 7 This is a schematic diagram of an automatic sewing machine according to an embodiment of the present invention;

[0054] Figure 8 This is a schematic diagram of path conversion according to an embodiment of the present invention;

[0055] Figure 9 This is a schematic diagram of vector analysis according to an embodiment of the present invention;

[0056] Figure 10This is a flowchart of a curved sewing method according to an embodiment of the present invention;

[0057] Figure 11 This is a flowchart illustrating the control of a robotic arm to move fabric according to an embodiment of the present invention;

[0058] Figure 12 This is a flowchart illustrating the discretization process of a curve according to an embodiment of the present invention;

[0059] Figure 13 This is a flowchart of the correction process according to an embodiment of the present invention.

[0060] In the attached figures, the following labels are used:

[0061] 1: Automatic sewing machine;

[0062] 10: Control module;

[0063] 11: Robotic arm module;

[0064] 110: Arm controller;

[0065] 111: First robotic arm module;

[0066] 112: Second robotic arm module;

[0067] 12: Sewing module;

[0068] 120: Sewing controller;

[0069] 121: Presser foot;

[0070] 122: sewing needle;

[0071] 13: Fabric feeding module;

[0072] 130: Fabric feed controller;

[0073] 14: Image capturing module;

[0074] 15: Human-computer interface;

[0075] 16: Storage module;

[0076] 17: Template;

[0077] 170: First template;

[0078] 171: Second template;

[0079] 20: Graphics Acquisition Module;

[0080] 21: Discrete processing module;

[0081] 22: Mobility control module;

[0082] 23: Correction processing module;

[0083] 30: Fabric;

[0084] 300: First fabric;

[0085] 301: Second fabric;

[0086] 31: Workbench;

[0087] 40: Sewing patterns;

[0088] A1: Presser foot area;

[0089] C1, C2: Discrete line segments;

[0090] D1: Fabric feeding direction;

[0091] P0-P28: Sewing points;

[0092] V10, V21: Vectors;

[0093] V10a, V10b, V20a, V20b: Components;

[0094] S10-S12: Automatic sewing steps;

[0095] S20-S21: Path conversion steps;

[0096] S30-S31: Sewing steps;

[0097] S40-S42: Control movement steps;

[0098] S50-S51: Discretization steps;

[0099] S60-S63: Calibration steps. Detailed Implementation

[0100] A preferred embodiment of the present invention will now be described in detail with reference to the accompanying drawings.

[0101] Please see Figure 1 , Figure 1 This is a structural diagram of an automatic sewing machine according to an embodiment of the present invention.

[0102] This invention proposes an automatic sewing machine 1 with curved sewing function. The automatic sewing machine 1 mainly includes a robotic arm module 11, a sewing module 12, a fabric feeding module 13, and a control module 10 electrically connected to the above modules.

[0103] Robotic arm module 11 is used to move the fabric on the sewing plane.

[0104] In one embodiment, the robotic arm module 11 has multiple degrees of freedom and can move in three-dimensional space to change its posture. In different postures, the end effector (such as an end effector or the template 17 described later) of the robotic arm module 11 can be moved to different positions in three-dimensional space.

[0105] In one embodiment, the end of the robotic arm module 11 has a mechanism for fixing fabric, so that the fabric can move (including translation and rotation) with the end of the robotic arm module 11.

[0106] In one embodiment, the robotic arm module 11 includes multiple transmission mechanisms, multiple motors, and multiple robotic arms. The multiple motors provide power to the multiple transmission mechanisms, thereby enabling the multiple transmission mechanisms to drive the multiple robotic arms, allowing the robotic arm module 11 to assume different postures.

[0107] It is worth mentioning that during the sewing process (such as when the sewing module 12 is performing sewing), the robotic arm module 11 can be restricted to moving only on the sewing plane (such as the XY axis plane), and cannot move in the vertical direction of the sewing plane (such as the Z axis direction). In this way, the present invention can avoid sewing failure caused by the robotic arm module 11 pulling the fabric in the vertical direction during the sewing process.

[0108] In one embodiment, the reference point of the aforementioned sewing plane may be the position of the sewing needle, the flange shaft of the robotic arm module 11, or other reference devices, without limitation.

[0109] The sewing module 12 is used to sew fabric, such as embroidering stitch patterns on the fabric (embroidery), or sewing multiple pieces of fabric together (stitching). The sewing module 12 can use an existing sewing machine, or it can perform sewing through an electrical device, motor, mechanical structure, thread feed module, needle module, etc.

[0110] The fabric feeding module 13 is set with a fabric feeding direction (such as the Y-axis direction, but not limited thereto) and can feed fabric to the sewing module 12 along the fabric feeding direction of the sewing plane.

[0111] In one embodiment, the fabric feeding module 13 can feed fabric via a motor and a fabric clamping mechanism. Furthermore, the fabric feeding speed of the fabric feeding module 13 can be adjusted by adjusting the motor speed.

[0112] It is worth mentioning that the sewing technology principle of the sewing module 12 and the fabric feeding module is easily understood by those with general knowledge in the field of automatic sewing technology, and will not be elaborated here.

[0113] The control module 10, such as a control board or control computer with a processor and programmable storage media, is electrically connected to the robotic arm module 11, the fabric feeding module 12, and the sewing module 13, and is used to control the movements of the robotic arm module 11, the fabric feeding module 12, and the sewing module 13.

[0114] In one embodiment, the control module 10 can be configured to obtain the sewing pattern of the fabric, perform path conversion on the sewing pattern to obtain a sewing path including multiple sewing points, control the robotic arm module 11 to move the fabric based on the sewing path, and coordinate with the fabric feeding module 12 and the sewing module 13 to feed and sew the fabric, thereby realizing the curved sewing of the present invention.

[0115] It is worth mentioning that, since the fabric feeding module 13 can only pull the fabric in a single direction (such as the Y-axis direction), the present invention can change the relative direction of the fabric to the sewing module 12 by translating or rotating the fabric in other directions on the same plane (such as the X-axis direction, or any direction of the XY plane) through the robotic arm module 11, thereby realizing curved sewing.

[0116] Please see Figure 2 , Figure 2 This is a structural diagram of an automatic sewing machine according to an embodiment of the present invention.

[0117] In one embodiment, the robotic arm module 11 includes an arm controller 110. The arm controller 110 is used to control the movement and posture of the robotic arm according to received arm control commands.

[0118] Specifically, the control module 10 can generate and send arm control commands to the arm controller 110. These arm control commands can indicate the movement speed, direction of movement, and / or destination of the robotic arm module 11. The movement speed, direction of movement, and / or destination can be vectors or coordinates based on a spatial coordinate system.

[0119] The arm controller 110 can convert the received arm control commands into coordinates in the robot coordinate system (such as the angles of each joint or the rotation degrees of the motors), and adjust the posture of the robotic arm module 11 based on these coordinates.

[0120] In one embodiment, the sewing module 12 may include a sewing controller 120. The sewing controller 120 is used to control the motor speed to control the needle speed based on received sewing control commands.

[0121] Specifically, the control module 10 can generate and send sewing control commands to the sewing controller 120. The aforementioned sewing control commands can indicate the sewing speed.

[0122] The sewing controller 120 can convert the received sewing control commands into corresponding sewing motor speed control signals, and adjust the sewing speed through the sewing motor speed control signals.

[0123] In one embodiment, the fabric feeding module 13 may include a fabric feeding controller 130. The fabric feeding controller 130 is used to control the rotation of the motor according to the received fabric feeding control command, so as to control the fabric feeding speed.

[0124] Specifically, the control module 10 can generate and send fabric feeding control commands to the fabric feeding controller 130. The aforementioned fabric feeding control commands can indicate the fabric feeding speed, fabric feeding length, etc.

[0125] The fabric feeding controller 130 can convert the received fabric feeding control command into a corresponding fabric feeding motor speed control signal, and adjust the fabric feeding speed and fabric feeding length through the fabric feeding motor speed control signal.

[0126] Therefore, the present invention allows for adjustment of the seam spacing by adjusting the sewing speed and the fabric feeding speed.

[0127] In one embodiment, the control module 10 can simultaneously control the arm controller 110, the sewing controller 120 and the fabric feeding controller 130 through the aforementioned commands, so that the speed at which the robotic arm module 11 moves the fabric, the sewing speed of the sewing module 12 and the fabric feeding speed of the fabric feeding module 13 reach the most harmonious state, and thus complete the sewing pattern on the fabric.

[0128] In one embodiment, when the fabric feeding speed and fabric feeding length are fixed, the control module 10 can calculate the rotation angle and / or displacement corresponding to each sewing point based on the calculated multiple sewing points of the fabric and trigonometric functions.

[0129] In one embodiment, the automatic sewing machine 1 may include a template 17. The template 17 is used to hold the fabric flat against the worktable (corresponding to the sewing plane) to facilitate sewing.

[0130] Furthermore, the end of the robotic arm module 11 can be connected to the template 17. In this way, the robotic arm module 11 can translate and rotate the fabric by moving the template 17 on the worktable.

[0131] In one embodiment, the automatic sewing machine 1 may include an image capturing module 14, such as a visible light camera. The image capturing module 14 is used to photograph the sewn fabric to obtain a result image of the fabric. The aforementioned result image can be used to perform sewing quality confirmation and sewing correction.

[0132] In one embodiment, the automatic sewing machine 1 may include a human-machine interface 15. The human-machine interface 15 is used to receive user operations and provide information, and may include input interfaces and output interfaces. Input interfaces may be, for example, a keyboard, mouse, touchpad, and / or other input interfaces. Output interfaces may be, for example, a display, buzzer, speaker, printer, and / or other output interfaces.

[0133] In one embodiment, the automatic sewing machine 1 may include a storage module 16. The storage module 16 is used to store data.

[0134] Please see Figure 3 , Figure 3 This is an architectural diagram of a control module according to an embodiment of the present invention. In the present invention, the control module 10 of the automatic sewing machine 1 may include a graphic acquisition module 20, a discrete processing module 21, a movement control module 22, and a correction processing module 23 for implementing different functions.

[0135] The graphic acquisition module 20 is configured to read the sewing graphic of the fabric from the storage module 16.

[0136] In one embodiment, the aforementioned sewing pattern is stored in a 2D / 3D graphic file format and may be designed, for example, by garment pattern making software, such as AutoCAD DXF or other CAD file formats, without limitation.

[0137] The discretization module 21 is configured to perform discretization processing on the curve of the sewing pattern to convert the curve into multiple sewing points.

[0138] The motion control module 22 is configured to calculate and determine the movement mode of the robotic arm module 11, and to realize the movement of the robotic arm module 11 through control commands.

[0139] The correction processing module 23 is configured to calculate the current sewing offset based on the result image and correct the movement of the robotic arm module 11 based on the offset, so that the correction robotic arm module 11 can accurately change the relative direction between the fabric and the sewing module 12, so as to accurately send the sewing point of the fabric to the sewing module 13 along the fabric feeding direction.

[0140] It is worth mentioning that the aforementioned graphics acquisition module 20, discrete processing module 21, motion control module 22 and correction processing module 23 are interconnected (either electrically or informationally), and can be hardware modules (such as electronic circuit modules, integrated circuit modules, SoC, etc.), software modules, or a combination of hardware and software modules, without limitation.

[0141] When the aforementioned image acquisition module 20, discrete processing module 21, movement control module 22 and / or correction processing module 23 are software modules (such as firmware, operating system or application program), the storage module 16 of the automatic sewing machine 1 may include a non-transient computer-readable recording medium. The aforementioned non-transient computer-readable recording medium stores a computer program, and the computer program records computer-executable program code. When the control device 10 executes the aforementioned program code, it can realize the functions of the aforementioned image acquisition module 20, discrete processing module 21, movement control module 22 and / or correction processing module 23.

[0142] Please see Figure 4 , Figure 4 This is a schematic diagram of an automatic sewing machine according to an embodiment of the present invention.

[0143] In this embodiment, the end of the robotic arm module 11 is connected to a template 17. The template 17 is used to fix the fabric 30 to the worktable 31.

[0144] When the fabric feeding module 13 starts feeding the fabric 30 along the feeding direction D1, the sewing module 12 starts sewing the fabric 30 that has passed through the needle.

[0145] At the same time, the robotic arm module 11 can rotate the fabric 30 in accordance with the rotating template 17, so that each sewing point set on the fabric 30 passes through the sewing module 12 along the fabric feeding direction D1 to complete the curved sewing.

[0146] In one embodiment, when applied to the sewing of multiple fabrics, other fabrics besides fabric 30 can be fed by the fabric feeding module 13 in the sewing plane, and the robotic arm module 11 moves fabric 30 to meet the joint of other fabrics. When the joint passes through the sewing module 12 along the fabric feeding direction D1, the sewing is completed.

[0147] Please see Figure 5 , Figure 5 This is a schematic diagram of an automatic sewing machine according to an embodiment of the present invention.

[0148] In this embodiment, two fabrics 300 and 301 can be moved by two sets of robotic arm modules 111 and 112 respectively, so as to realize the sewing of the two fabrics 300 and 301.

[0149] Specifically, on one side of the workbench 31 (as shown above), the robotic arm module 111 is connected to the template 170, which is used to fix the fabric 300 above. The robotic arm module 111 can change the relative orientation between the fabric 300 and the sewing module 12 by moving the template 170.

[0150] On the other side of the workbench 31 (as shown below), the robotic arm module 112 is connected to the template 171, which is used to fix the fabric 301 below. The robotic arm module 112 can change the relative orientation between the fabric 301 and the sewing module 12 by moving the template 171.

[0151] Next, through the coordinated movement of the fabric feeding module 13, the robotic arm module 111 and the robotic arm module 112, the joint between the fabric 300 and the fabric 301 (with a sewing point) can pass through the sewing module 12 along the fabric feeding direction D1, and the sewing at the joint can be completed.

[0152] Please see Figure 6 and Figure 7 , Figure 6 This is a schematic diagram of an automatic sewing machine according to an embodiment of the present invention. Figure 7 This is a schematic diagram of an automatic sewing machine according to an embodiment of the present invention. Figure 6 and Figure 7 Schematic diagrams showing different perspectives of an automatic sewing machine.

[0153] As shown in the figure, the sewing module 12 includes a presser foot 121 and a sewing needle 122.

[0154] In one embodiment, to better suit curved sewing, the area of ​​the presser foot 121 can be further reduced, thereby reducing the resistance brought by the presser foot 121 when rotating the fabric 30.

[0155] The sewing pattern 40 of the fabric 30 may include straight lines and curves. In this invention, the fabric 30 is translated or rotated by the robotic arm module 11 so that each position of the sewing pattern 40 moves along the fabric feeding direction D1 when passing through the presser foot 121 and the sewing needle 122 of the sewing module 12.

[0156] Please see Figure 10 , Figure 10 This is a flowchart of a curved sewing method according to an embodiment of the present invention. The curved sewing methods of the various embodiments of the present invention can be applied to any of the automatic sewing machines 1 of the present invention.

[0157] The curve sewing method of this embodiment may include steps S10-S12.

[0158] In step S10, the control module 10 obtains the sewing pattern of the fabric through the graphics acquisition module 20.

[0159] In step S11, the control module 10 performs path conversion on the sewing pattern through the discrete processing module 21 to obtain the sewing path corresponding to the sewing pattern. The aforementioned sewing path includes multiple sewing points. The multiple sewing points correspond to the expected sewing positions (virtual set positions) on the fabric.

[0160] In one embodiment, the aforementioned plurality of sewing points have a fixed seam spacing.

[0161] In one embodiment, the seam spacing of the aforementioned plurality of sewing points is adjustable and corresponds to the set sewing speed and fabric feeding speed.

[0162] Furthermore, when the sewing speed and fabric feeding speed change, the speed at which the robotic arm module 11 moves the fabric must also change accordingly.

[0163] In one embodiment, the path conversion in step S11 may include step S20, or may include steps S20 and S21.

[0164] In step S20, the control module 10 performs discretization processing on the curve through the discretization processing module 21 to discretize the curve of the sewing pattern and obtain multiple sewing points arranged along the curve.

[0165] In step S21, the control module 10 performs discretization processing of the straight line through the discretization processing module 21 to discretize the straight line of the sewing pattern and obtain multiple sewing points arranged along the straight line.

[0166] Please see, Figure 8 This is a schematic diagram of path conversion according to an embodiment of the present invention.

[0167] At Figure 8 In one embodiment, discretization transformation is performed only on the curve in the sewing pattern 40 to obtain multiple sewing points P0-P27 arranged along the curve.

[0168] For the straight lines in the sewing pattern 40, the present invention can directly set sewing points P27 and P28 at the start and end points of the straight lines without performing discretization transformation, thereby reducing the amount of computation.

[0169] Please refer to the following: Figure 10 In step S12, the control module 10 executes the sewing program through the movement control module 22.

[0170] In one embodiment, the control module 10 can simultaneously execute steps S30-S32 in the sewing program.

[0171] In step S30, the control module 10 controls the fabric feeding module 13 to feed the fabric to the sewing module 12 along the fabric feeding direction D1 of the sewing plane through the movement control module 22.

[0172] In step S31, the control module 10 controls the sewing module 12 to sew the fabric through the movement control module 22.

[0173] In step S32, the control module 10 controls the robotic arm module 11 to move the fabric through the motion control module 22.

[0174] In one embodiment, the control module 10 controls the robotic arm module 11 to move the fabric on the sewing plane based on the multiple sewing points set by the motion control module 22, so that the multiple sewing points pass through the sewing module 12 in sequence along the fabric feeding direction D1.

[0175] Therefore, the present invention can realize curved sewing.

[0176] Please see Figure 10 and Figure 11 , Figure 11 This is a flowchart illustrating the control of a robotic arm to move fabric according to an embodiment of the present invention.

[0177] Step S32 of the curved sewing method in this embodiment may include the following steps S40-S42.

[0178] In step S40, the control module 10 calculates the sewing vectors of multiple sewing points through the movement control module 22.

[0179] In step S41, the control module 10 determines the movement vector or movement coordinates of the robotic arm module 11 through the movement control module 22.

[0180] In one embodiment, the control module 10 can determine the movement vector or movement coordinates of the robotic arm module 11 by the movement control module 22 based on at least one of the default seam spacing, preset seam speed and preset needle drop interval and the sewing vector determined in step S40.

[0181] The aforementioned preset seam spacing, preset seam speed, and preset needle drop interval can be preset by the user or automatically determined by the automatic sewing machine 1.

[0182] In step S42, the control module 10 controls the robotic arm module 11 to move the fabric based on the movement vector or movement coordinate determined in step S41 by the movement control module 22, so that the sewing vectors of the multiple sewing points set on the fabric are parallel to the fabric feeding direction D1.

[0183] In one embodiment, the control module 10 can control the robotic arm module 11 to move the template 17 via the motion control module 22, thereby translating and rotating the fabric in the sewing plane.

[0184] In one embodiment, the multiple movement coordinates can be multiple destination coordinates of the robotic arm module 11 for multiple sewing points. The control module 10 can control the robotic arm module 11 to move sequentially to each movement coordinate through the movement control module 22, so that the sewing vector corresponding to each sewing point when passing through the sewing module 12 is parallel to the fabric feeding direction.

[0185] In one embodiment, the multiple movement vectors may be multiple velocity vectors of the robotic arm module 11 for multiple sewing points. Each velocity vector includes a first velocity component and an angular velocity component. The first velocity component is parallel to the fabric feeding direction. Both the first velocity component and the angular velocity component are vectors on the sewing plane.

[0186] The control module 10 can control the robotic arm module 11 to move the fabric based on the first velocity component and angular velocity component corresponding to each sewing point through the motion control module 22, so that when each sewing point set on the fabric passes through the sewing module 12, its sewing vector is parallel to the fabric feeding direction.

[0187] It is worth mentioning that, in order to solve the problem of internal stress in elastic fabric when sewing curves, the present invention can use an r-θ coordinate system, where r is the velocity vector and θ is the angular velocity component, and r-θ can be used to obtain the first velocity component r' (details to follow).

[0188] Please see Figures 10 to 12 , Figure 12 This is a flowchart illustrating the discretization process of a curve according to an embodiment of the present invention.

[0189] Step S20 of the curved sewing method in this embodiment may include the following steps S50-S51.

[0190] It is worth mentioning that the discretization process shown in steps S50-S51 can also be used for straight lines without limitation.

[0191] In step S50, the control module 10 divides the curve into multiple discrete line segments through the discrete processing module 21.

[0192] In one embodiment, the lengths of the multiple discrete line segments may be the same or different, without limitation.

[0193] In one embodiment, the length of each of the aforementioned discrete line segments is not greater than a preset fixed gap.

[0194] In step S51, the control module 10 performs linear interpolation on multiple discrete line segments through the discrete processing module 21 to obtain multiple sewing points corresponding to the multiple discrete line segments.

[0195] In one embodiment, the aforementioned linear interpolation determines the start and end points of each discrete line segment to serve as the aforementioned multiple sewing points.

[0196] In one embodiment, the aforementioned linear interpolation is based on determining the midpoint of each discrete line segment from its start and end points, which is then used as the aforementioned sewing point.

[0197] Please see Figure 8 and Figure 9 , Figure 9This is a schematic diagram of vector analysis according to an embodiment of the present invention.

[0198] In this embodiment, the presser foot 121 has a presser foot area A1.

[0199] The front end of the sewing pattern 40 can be divided into discrete line segments C1 and C2. The sewing points P0-P2 can be obtained by interpolating the discrete line segments C1 and C2.

[0200] Next, the present invention can calculate the sewing vector V10 for sewing points P0-P1 and the sewing vector V21 for sewing points P1-P2. The sewing vectors V10 and V21 can be displacement vectors or velocity vectors, without limitation.

[0201] For example, the sewing vector V10 is the same as the velocity vector r1 that the robotic arm module 11 should use. When the velocity vector r1 is rotated by the angular velocity component θ1, the first velocity component r1' parallel to the fabric feeding direction D1 can be obtained (that is, the rotated sewing vector V10 can be parallel to the fabric feeding direction D1).

[0202] When it is desired that the sewing point P1 passes through the needle along the fabric feeding direction D1, the robotic arm module 11 must independently provide a rotation corresponding to the angular velocity component θ1 to the fabric, and together with the fabric feeding module 13, provide a movement corresponding to the first velocity component r1' to the fabric (or the fabric feeding module 13 independently provides a movement corresponding to the first velocity component r1' to the fabric). In other words, the robotic arm module 11 can rotate by an angle θ1 and then move parallel to the fabric feeding direction D1, and based on the attitude parallel to the fabric feeding direction D1, move the first velocity component r1' to make the sewing point P1 pass through the needle.

[0203] Next, the sewing vector V21 is the same as the velocity vector r2 that the robotic arm module 11 should use. After rotating the velocity vector r2 by the angular velocity component θ2, the first velocity component r2' parallel to the fabric feeding direction D1 can be obtained (that is, the rotated sewing vector V21 can be parallel to the fabric feeding direction D1).

[0204] When it is desired that the sewing point P2 passes through the needle along the fabric feeding direction D1, the robotic arm module 11 must independently provide a rotation corresponding to the angular velocity component θ2 to the fabric, and together with the fabric feeding module 13, provide a movement corresponding to the first velocity component r2' to the fabric (or the fabric feeding module 13 independently provides a movement corresponding to the first velocity component r2' to the fabric). In other words, the robotic arm module 11 can rotate by an angle θ2 and then move parallel to the fabric feeding direction D1, and based on the posture parallel to the fabric feeding direction D1, move the first velocity component r2' to make the sewing point P2 pass through the needle, and so on.

[0205] This invention uses the sewing needle as the center and employs an r-θ motion control method to achieve the technical effect of minimizing the internal stress of the elastic fabric during curved sewing.

[0206] Please see Figures 10 to 13 , Figure 13 This is a flowchart of the correction process according to an embodiment of the present invention.

[0207] The curve sewing method of this embodiment can perform the following steps S60-S61 simultaneously with or after performing step S12 (sewing program) to correct the robotic arm module 11 in real time or afterward.

[0208] In step S60, the control module 10 controls the image capturing module 14 to take pictures of the sewn fabric through the correction processing module 23 to obtain the result image.

[0209] In step S61, the control module 10 calculates the offset based on the result image through the correction processing module 23.

[0210] In one embodiment, the control module 10 can identify the actual sewing position of each seam point on the fabric in the result image, and calculate the offset between the actual sewing position of each seam point and the expected seam position to obtain the offset amount.

[0211] In one embodiment, the control module 10 can identify the actual sewing pattern in the result image and calculate the deviation between it and the virtual sewing pattern used in step S10 to obtain the offset.

[0212] In step S62, the control module 10 determines whether the offset meets the preset correction conditions through the correction processing module 23.

[0213] In one embodiment, the correction condition may include a non-zero offset, i.e., the presence of any offset.

[0214] In one embodiment, the correction condition may include an offset exceeding a preset offset threshold, i.e., a significant offset exists.

[0215] If the offset does not meet the preset correction conditions, the correction will end.

[0216] If the offset meets the preset correction conditions, then step S63 is executed. In step S63, the control module 10 corrects the movement of the robotic arm module 11 based on the offset by the correction processing module 23.

[0217] In one embodiment, the control module 10 can decompose the offset into X-axis and Y-axis components (such as the fabric feeding direction). The movement of the robotic arm module 11 is then compensated for based on the X-axis and Y-axis components to offset the offset.

[0218] In one embodiment, the control module 10 can add an offset to the reference posture of the robotic arm module 11 to correct all postures of the robotic arm module 11 (based on the reference posture) by compensating for the reference posture.

[0219] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the patent. Therefore, all equivalent variations made using the content of the present invention are similarly included within the scope of the present invention and are hereby declared.

[0220] Of course, the present invention may have other various embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and modifications according to the present invention, but these corresponding changes and modifications should all fall within the protection scope of the claims of the present invention.

Claims

1. An automatic sewing machine with curved sewing function, characterized in that, include: A robotic arm module for moving a piece of fabric on a sewing plane; A sewing module for sewing the fabric; A fabric feeding module for feeding the fabric to the sewing module along a fabric feeding direction of the sewing plane; and A control module, electrically connected to the robotic arm module, the fabric feeding module, and the sewing module, is configured to acquire a sewing pattern of the fabric, perform a path transformation on the sewing pattern to obtain a sewing path including multiple sewing points, and control the robotic arm module to move the fabric based on the multiple sewing points so that the multiple sewing points pass through the sewing module along the fabric feeding direction. The control module includes a motion control module, which is configured to calculate a sewing vector of the plurality of sewing points, and determine a motion vector or a motion coordinate of the robotic arm module based on at least one of a preset seam distance, a preset sewing speed and a preset needle drop interval and the sewing vector, and control the movement of the robotic arm module based on the motion vector or the motion coordinate so that the sewing vector is parallel to the fabric feeding direction.

2. The automatic sewing machine according to claim 1, characterized in that, These multiple sewing points have a fixed seam spacing; The control module includes a discrete processing module, which is configured to divide a curve of the sewing pattern into multiple discrete line segments and perform linear interpolation on the multiple discrete line segments to obtain the multiple sewing points corresponding to the multiple discrete line segments. The length of each discrete line segment is not greater than the fixed seam distance.

3. The automatic sewing machine according to claim 1, characterized in that, The movement vector is a velocity vector, and includes a first velocity component and a second velocity component, wherein the first velocity component is parallel to the fabric feeding direction; The motion control module is configured to control the movement of the robotic arm module based on the first velocity component and the second velocity component, so that the sewing vector of the multiple sewing points is parallel to the fabric feeding direction when the multiple sewing points pass through the sewing module.

4. The automatic sewing machine according to claim 1, characterized in that, The movement coordinates are the destination coordinates of the robotic arm module; The motion control module is configured to control the robotic arm module to move to the motion coordinate, so that when the multiple sewing points pass through the sewing module, the sewing vector of the multiple sewing points is parallel to the fabric feeding direction.

5. The automatic sewing machine according to claim 1, characterized in that, It also includes a template for fixing the fabric, the robotic arm module is connected to the template, and the fabric is translated and rotated on the sewing plane by moving the template.

6. The automatic sewing machine according to claim 1, characterized in that, It also includes an image capturing module for capturing a resulting image of the fabric; The control module includes a correction processing module, which is configured to correct the movement of the robotic arm module based on the offset when the offset of the plurality of sewing points in the detected result image meets a correction condition.

7. A method for sewing curved lines, characterized in that, include: a) Obtain a sewing pattern from a piece of fabric; b) Perform a path transformation on the sewing pattern to obtain a sewing path corresponding to the sewing pattern, wherein the sewing path includes multiple sewing points; c) In a sewing program, a fabric feeding module is controlled to feed the fabric to a sewing module along a feeding direction on a sewing plane, and the sewing module is controlled to sew the fabric; and d) In the sewing process, a robotic arm module is controlled to move the fabric on a sewing plane based on the multiple sewing points so that the multiple sewing points pass through the sewing module along the fabric feeding direction; This path transformation includes: e) Perform a discretization transformation on a curve of the sewing pattern to obtain the plurality of sewing points arranged along the curve. Step d) includes: d1) Calculate a sewing vector for the multiple sewing points; d2) Based on at least one of a preset seam spacing, a preset seam speed, and a preset needle insertion interval, and the sewing vector, determine a movement vector or a movement coordinate of the robotic arm module; and d3) Control the movement of the robotic arm module based on the movement vector or the movement coordinates to make the sewing vector parallel to the fabric feeding direction.

8. The curved sewing method according to claim 7, characterized in that, These multiple sewing points have a fixed seam spacing; The discretization transformation includes: f1) Divide the curve into multiple discrete line segments, wherein the length of each discrete line segment is no greater than the fixed seam spacing; and f2) Perform linear interpolation on the multiple discrete line segments to obtain the multiple stitching points corresponding to the multiple discrete line segments.

9. The curved sewing method according to claim 7, characterized in that, The movement vector is a velocity vector, and includes a first velocity component and an angular velocity component, wherein the first velocity component is parallel to the fabric feeding direction; In step d3), the movement of the robotic arm module is controlled based on the first velocity component and the angular velocity component, so that the sewing vector of the multiple sewing points is parallel to the fabric feeding direction when the multiple sewing points pass through the sewing module.

10. The curved sewing method according to claim 7, characterized in that, The movement coordinates are the destination coordinates of the robotic arm module; In step d3), the robotic arm module is controlled to move to the moving coordinate so that the sewing vector of the multiple sewing points is parallel to the fabric feeding direction when the multiple sewing points pass through the sewing module.

11. The curved sewing method according to claim 7, characterized in that, Step d) involves controlling the robotic arm module to move a template used to fix the fabric, thereby translating and rotating the fabric on the sewing plane.

12. The curved sewing method according to claim 7, characterized in that, more include: g1) In this sewing process, a result image is captured by an image capturing module; and g2) When the offset of one of the multiple sewing points in the detected result image meets a correction condition, the movement of the robotic arm module is corrected based on the offset.

Images