An automatic compensation method for stitch length at the inner and outer corners of a stepping roller sewing machine

Abstract

This invention belongs to the field of roller sewing technology, specifically referring to an automatic compensation method for stitch length at inner and outer corners of a stepping roller sewing machine. It includes a roller body, and a needle, upper feed roller, and lower feed roller mounted on the roller body. The roller body is equipped with a detection module for detecting changes in the planar displacement of the sewing material. This detection module converts the changes in material displacement ΔX in the X-axis direction and ΔY in the Y-axis direction into continuous turning angles for inner and outer corners. The main controller receives these angles and calculates the stitch length compensation amount based on the continuous turning angles, thereby controlling the upper and lower feed rollers or a stitch length adjustment component to perform stitch length compensation. This invention utilizes the detection module to detect and acquire the changes in material displacement in the XY-axis directions in real time during sewing, converting them into continuous turning angles for inner and outer corners. These angles are then used to compensate for stitch length errors, ensuring consistent stitch length and guaranteeing sewing quality.

Description

Technical fields:

[0001] This invention belongs to the field of roller sewing technology, specifically referring to an automatic compensation method for stitch length at the inner and outer corners of a stepping roller sewing machine. Background technology:

[0002] Roller sewing machines, used for sewing and embellishing leather, are primarily used for sewing high-end leather shoes, bags, straps, and curved belts. Stepper roller sewing machines, in particular, utilize stepper motors to drive the upper and lower rollers and needle for synchronous feeding, and can adjust the stitch length using a stitch length adjustment component.

[0003] Because the stitch length changes when sewing inside and outside corners on a stepping roller sewing machine—that is, the stitch length becomes smaller when sewing inside corners and larger when sewing outside corners—there is a problem of uneven stitches when sewing curved lines.

[0004] The current solution involves manual intervention to achieve stitch length compensation, using external buttons to achieve fixed stitch length compensation for internal and external corners. However, this method has the following problems: 1. It is inconvenient to operate manually, easy to press the wrong button, and once the wrong button is pressed, the sewing material will be ruined; 2. The amount of stitch length compensation is fixed each time, and continuous compensation cannot be achieved. As a result, the stitch length after compensation often still has deviation, affecting the quality of sewing. Summary of the Invention:

[0005] The purpose of this invention is to provide an automatic compensation method for stitch length at the inner and outer corners of a stepping roller sewing machine. The method uses a detection module to detect the displacement change of the sewing material in the XY coordinate direction in real time, which is converted into the continuous turning angle of the inner and outer corners, thereby compensating for stitch length errors and achieving consistency in sewing stitch length.

[0006] This invention is implemented as follows:

[0007] An automatic stitch length compensation method for sewing at inner and outer corners of a stepping roller carriage includes a roller carriage body, and a needle, an upper feed roller, and a lower feed roller mounted on the roller carriage body. A feeding station for conveying sewing material is formed between the needle, the upper feed roller, and the lower feed roller. The needle is driven up and down by a spindle and its stitch length is adjusted by a stitch length adjustment component. The roller carriage body is equipped with a detection module for detecting the planar displacement change of the sewing material within the feeding station. This detection module converts the displacement change ΔX in the X-coordinate direction and the displacement change ΔY in the Y-coordinate direction of the sewing material into continuous turning angles of the inner and outer corners. The main controller receives these angles and calculates the stitch length compensation amount based on the continuous turning angles of the inner and outer corners to control the upper feed roller, the lower feed roller, or the stitch length adjustment component to perform stitch length compensation.

[0008] In the above-mentioned method for compensating stitch length at the inner and outer corners of a stepping roller sewing machine, the detection module is a contact displacement sensing module that is in direct contact with the sewing material.

[0009] Alternatively, the detection module may be an optical flow detection module with the detection end facing the sewing material.

[0010] In the above-mentioned method for compensating stitch length at the inner and outer corners of a stepping roller sewing machine, the optical flow detection module includes an optical flow sensor and an MCU microcontroller. The MCU microcontroller reads the detection information detected by the optical flow sensor in real time through a high-speed serial port to obtain the displacement change ΔX of the sewing material in the X-coordinate direction and the displacement change ΔY in the Y-coordinate direction. The displacement change ΔX and displacement change ΔY are then converted into the continuous turning angle of the inner and outer corners according to a set continuous turning angle conversion formula.

[0011] In the above-mentioned method for compensating stitch length at the inner and outer corners of a stepping roller carriage, the optical flow detection module is fixed on the upper roller bracket, which is a connecting part of the roller carriage body used to connect to the upper feeding roller.

[0012] Alternatively, the optical flow detection module may be fixed on the lower roller bracket, which is a connector on the roller car body used to connect to the lower feeding roller;

[0013] Alternatively, the optical flow detection module may be fixed to the lower base plate of the roller car body.

[0014] In the above-mentioned method for compensating stitch length at the inner and outer corners of a stepping roller sewing machine, the upper feed roller is driven by an upper roller stepper motor, and the upper feed roller rotates. The lower feed roller is driven by a lower roller stepper motor, and the lower feed roller rotates. Both the upper and lower roller stepper motors are electrically connected to a main controller, and the main controller controls the rotation of the upper and lower roller stepper motors to perform stitch length compensation.

[0015] In the above-mentioned method for compensating for stitch length at the inner and outer corners of a stepping roller sewing machine, the formula for converting continuous turning angles is:

[0016] θ = arctan(△Y / △X);

[0017] θ greater than 0 is the outer corner angle, and θ less than 0 is the inner corner angle.

[0018] In the above-mentioned method for compensating stitch length at the inner and outer corners of a stepping roller sewing machine, the initial stitch length is set to L, k is the compensation coefficient, and the maximum stitch length after compensation is set to Lmax and the minimum stitch length after compensation is set to Lmin.

[0019] The formula for calculating the compensated stitch length Lc is: Lc = f(L, k, θ), which is a function with L, k, and θ as variables, such as Lc = Lk * θ;

[0020] If Lc is greater than Lmax, then Lc = Lmax;

[0021] If Lc is less than Lmin, then Lc = Lmin.

[0022] In the above-mentioned method for compensating stitch length at the inner and outer corners of a stepping roller sewing machine, the stitch length adjustment component includes an upper roller stepper motor, a lower roller stepper motor, and a swaying needle stepper motor for adjusting the vertical amplitude of the needle bar. The upper roller stepper motor, the lower roller stepper motor, and the swaying needle stepper motor adjust the initial stitch length of the needle bar. The main shaft is driven to rotate by a main shaft servo motor to move the needle bar up and down. The main controller controls the working state of the upper roller stepper motor, the lower roller stepper motor, the swaying needle stepper motor, and the main shaft servo motor respectively.

[0023] The outstanding advantages of this invention compared to the prior art are:

[0024] This invention uses a detection module to detect and acquire the displacement change of the fabric in the XY coordinate direction in real time during the sewing process, and converts it into the continuous turning angle of the inner and outer corners. This angle is then used to compensate for the stitch length error, so as to ensure the consistency of the sewing stitch length and ensure the quality of the sewing. Attached image description:

[0025] Figure 1 This is a control framework diagram of the present invention.

[0026] In the diagram: 1. Main controller; 2. Optical flow detection module; 3. Optical flow sensor; 4. MCU microcontroller; 5. Upper roller stepper motor; 6. Lower roller stepper motor; 7. Needle stepper motor; 8. Spindle servo motor. Detailed implementation method:

[0027] The present invention will be further described below with reference to specific embodiments. See also: Figure 1 :

[0028] An automatic stitch length compensation method for sewing at inner and outer corners of a stepping roller carriage includes a roller carriage body, and a needle, an upper feed roller, and a lower feed roller mounted on the roller carriage body. The needle, upper feed roller, and lower feed roller form a feeding station for conveying sewing material. The needle is driven by a spindle to move up and down, and its stitch length is adjusted by a stitch length adjustment component. The roller carriage body is equipped with a detection module for detecting the change in planar displacement of the sewing material within the feeding station. This detection module can convert the change in displacement of the sewing material in the X-coordinate direction ΔX and the change in displacement in the Y-coordinate direction ΔY into continuous turning angles of inner and outer corners. The main controller 1 receives the data and calculates the stitch length compensation amount based on the continuous turning angles of the inner and outer corners to control the upper feed roller, lower feed roller, or stitch length adjustment component to perform stitch length compensation.

[0029] This invention uses a detection module to detect and acquire the displacement change of the fabric in the XY coordinate direction in real time during the sewing process, and converts it into the continuous turning angle of the inner and outer corners. This angle is then used to compensate for the stitch length error, so as to ensure the consistency of the sewing stitch length and ensure the quality of the sewing.

[0030] The detection module can be a contact displacement sensing module that is in direct contact with the sewing material;

[0031] In this embodiment, the detection module used is an optical flow detection module 2 with the detection end facing the fabric. The optical flow detection module 2 includes an optical flow sensor 3 and an MCU microcontroller 4. The MCU microcontroller 4 reads the detection information detected by the optical flow sensor 3 in real time via a high-speed serial port to obtain the displacement change ΔX in the X-coordinate direction and the displacement change ΔY in the Y-coordinate direction of the fabric. The displacement changes ΔX and ΔY are then converted into continuous turning angles of the inner and outer corners according to a set continuous turning angle conversion formula. Meanwhile, the MCU microcontroller 4 can be integrated with the main controller 1, or the two can be connected separately via communication.

[0032] It should be noted that the optical flow detection module 2 used in this embodiment has a built-in optical flow sensor, also known as an optical tracking sensor. This sensor measures position changes by optically acquiring continuous surface images and mathematically determining the direction and magnitude of movement. It integrates an image acquisition system, a digital signal processor, and a four-wire serial port. The image acquisition system acquires surface images through a lens and illumination system, and the digital signal processor processes these images to determine the direction and distance of movement, thereby calculating the relative displacement values ​​of ΔX and ΔY. The MCU microcontroller 4 can read the ΔX and ΔY information from the sensor's four-wire serial port. Since this optical flow sensor is existing technology, its composition and working principle will not be described in detail in this specification.

[0033] Furthermore, to facilitate the detection and acquisition of the displacement changes of the sewing material by the optical flow detection module 2, the optical flow detection module 2 is fixed on the upper roller bracket, which is a connector on the roller body used to connect the upper feed roller; of course, the optical flow detection module 2 can also be fixed on the lower roller bracket, which is a connector on the roller body used to connect the lower feed roller; at the same time, the optical flow detection module 2 can also be fixed on the lower base plate of the roller body.

[0034] Meanwhile, the stepper roller carriage has multiple motors as power sources to drive the execution unit to work. The upper feed roller is driven by the upper roller stepper motor 5, which drives the rotation of the upper feed roller. The lower feed roller is driven by the lower roller stepper motor 6, which drives the rotation of the lower feed roller. Both the upper roller stepper motor 5 and the lower roller stepper motor 6 are electrically connected to the main controller 1. The stitch length compensation can be implemented by the main controller 1 through the stitch length adjustment component. In this embodiment, the main controller 1 controls the rotation of the upper roller stepper motor 5 and the lower roller stepper motor 6 to perform stitch length compensation.

[0035] In order to convert the displacement changes ΔX and ΔY into continuous turning angles per stitch, the formula for converting continuous turning angles is as follows:

[0036] θ = arctan(△Y / △X);

[0037] θ greater than 0 is the outer corner angle, and θ less than 0 is the inner corner angle.

[0038] After the MCU microcontroller 4 transmits the converted continuous turning angle information to the main controller 1, the main controller 1 calculates the required stitch distance compensation amount based on the continuous turning angle information. The calculation method of the stitch distance compensation amount is as follows: set the initial stitch distance as L, k as the compensation coefficient, and set the maximum stitch distance after compensation as Lmax and the minimum stitch distance after compensation as Lmin.

[0039] The formula for calculating the compensated stitch length Lc is: Lc = f(L, k, θ), which is a function with L, k, and θ as variables, such as Lc = Lk * θ;

[0040] If Lc is greater than Lmax, then Lc = Lmax;

[0041] If Lc is less than Lmin, then Lc = Lmin.

[0042] Subsequently, the main controller 1 controls the displacement of the upper roller stepper motor 5 and the lower roller stepper motor 6 according to the calculated stitch pitch compensation amount, so as to achieve the purpose of compensating for stitch pitch error.

[0043] The initial stitch length L can be set according to the actual requirements of the sewing material and can be adjusted by the stitch length adjustment component. The stitch length adjustment component includes an upper roller stepper motor 5, a lower roller stepper motor 6, and a swing needle stepper motor 7 that adjusts the vertical amplitude of the needle bar. The upper roller stepper motor 5, the lower roller stepper motor 6, and the swing needle stepper motor 7 adjust the initial stitch length of the needle bar. The main shaft is driven to rotate by the main shaft servo motor 8 to drive the needle bar to move up and down. The main controller 1 controls the working status of the upper roller stepper motor 5, the lower roller stepper motor 6, the swing needle stepper motor 7, and the main shaft servo motor 8 respectively.

[0044] The above embodiments are merely one of the preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Therefore, all equivalent changes made in accordance with the shape, structure and principle of the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for automatic compensation of stitch length at the inner and outer corners of a stepping roller sewing machine, comprising a roller body, and a needle, an upper feed roller, and a lower feed roller mounted on the roller body, wherein the needle, the upper feed roller, and the lower feed roller form a feeding station for conveying sewing material, the needle is driven by a spindle to move up and down, and the stitch length is adjusted by a stitch length adjustment component, characterized in that: The roller body is equipped with a detection module for detecting the change in planar displacement of the sewing material in the feeding station. The detection module can convert the change in displacement of the sewing material in the X coordinate direction ΔX and the change in displacement in the Y coordinate direction ΔY into the continuous turning angle of the inner and outer corners. The main controller (1) receives the data and calculates the stitch length compensation based on the continuous turning angle of the inner and outer corners to control the stitch length adjustment component to perform stitch length compensation. The needle spacing adjustment assembly includes an upper roller stepper motor (5), a lower roller stepper motor (6), and a swaying needle stepper motor (7) for adjusting the vertical amplitude of the needle bar. The upper roller stepper motor (5), the lower roller stepper motor (6), and the swaying needle stepper motor (7) adjust the initial needle spacing of the needle bar. The main shaft is driven to rotate by a main shaft servo motor (8) to move the needle bar up and down. The main controller (1) controls the working status of the upper roller stepper motor (5), the lower roller stepper motor (6), the swaying needle stepper motor (7), and the main shaft servo motor (8) respectively. The upper feeding roller is connected to the upper roller stepper motor (5) for transmission, and the upper feeding roller is driven to rotate by the upper roller stepper motor (5). The lower feeding roller is connected to the lower roller stepper motor (6) for transmission, and the lower feeding roller is driven to rotate by the lower roller stepper motor (6). The upper roller stepper motor (5) and the lower roller stepper motor (6) are both electrically connected to the main controller (1), and the main controller (1) controls the rotation of the upper roller stepper motor (5) and the lower roller stepper motor (6) to perform needle pitch compensation. The formula for converting continuous turning angles is: θ = arccos(ΔY / ΔX); θ greater than 0 is the outer corner angle, and θ less than 0 is the inner corner angle; Set the initial stitch length to L, k to the compensation coefficient, and set the maximum stitch length after compensation to Lmax and the minimum stitch length after compensation to Lmin. The formula for calculating the needle spacing compensation is: Lc = Lk*θ; If Lc is greater than Lmax, then Lc = Lmax; If Lc is less than Lmin, then Lc = Lmin.

2. The method for compensating stitch length at the inner and outer corners of a stepping roller sewing machine according to claim 1, characterized in that: The detection module is a contact displacement sensing module that comes into direct contact with the sewing fabric. Alternatively, the detection module may be an optical flow detection module with the detection end facing the sewing material (2).

3. The method for compensating stitch length at the inner and outer corners of a stepping roller sewing machine according to claim 2, characterized in that: The optical flow detection module (2) includes an optical flow sensor (3) and an MCU microcontroller (4). The MCU microcontroller (4) reads the detection information detected by the optical flow sensor (3) in real time through a high-speed serial port to obtain the displacement change ΔX in the X coordinate direction and the displacement change ΔY in the Y coordinate direction of the seam material. The displacement change ΔX and displacement change ΔY are converted into the continuous turning angle of the inner and outer corners according to the set continuous turning angle conversion formula.

4. A method for compensating stitch length at the inner and outer corners of a stepping roller sewing machine according to claim 2 or 3, characterized in that: The optical flow detection module (2) is fixed on the upper roller bracket, which is a connecting part of the roller car body used to connect the upper feeding roller; Alternatively, the optical flow detection module (2) is fixed on the lower roller bracket, which is a connecting part of the roller car body used to connect the lower feeding roller; Alternatively, the optical flow detection module (2) may be fixed on the lower base plate of the roller car body.

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