Sewing system and method of controlling the same

Abstract

The present disclosure relates to a sewing system and a control method thereof. A sewing system is disclosed. The sewing system includes a robot configured to hold and move a fabric article, a sewing machine configured to sew the fabric article held by the robot, and a control unit configured to control a sewing operation of the sewing machine on the fabric article by receiving a speed of an end effector and a stitch pitch, calculating a theoretical rotational speed of an electric motor of the sewing machine based on the speed of the end effector and the stitch pitch, determining a value of an operating parameter of the electric motor related to the theoretical rotational speed, and setting the operating parameter to the determined value of the operating parameter. A method of controlling a sewing system is also disclosed.

Description

Technical Field

[0001] This disclosure relates to a sewing system and a method for controlling the sewing system. Background Technology

[0002] Sewing machines sew fabric together by using a needle and spool system to interlock the upper and lower threads. As the needle moves, the bobbin wraps the upper thread around the lower thread to form a lockstitch. A feeding system, such as a feed dog, propels the fabric forward. In modern sewing machines, the sewing operation is typically driven by an electric motor.

[0003] Sewing machines struggle to meet the high productivity demands of large-scale industrial sewing. To address this, Cartesian sewing machines utilize a frame with three linear axes (X, Y, and Z) controlled by servo motors to automate speed, position, and torque. However, this setup can imply complex calibrations, higher costs, and slower operation due to the precision required for movement. Furthermore, its limited workspace makes it unsuitable for handling relatively large pieces of fabric.

[0004] To meet productivity demands, robot assistance can be implemented in sewing operations. For example, integrating a sewing machine head with a robot end effector can avoid the size limitations of Cartesian systems and improve the flexibility of fabric handling. However, this approach can be challenging because adapting a robot to a sewing machine as an end effector can involve specialized hardware and advanced control algorithms, thus increasing cost and complexity.

[0005] This disclosure provides examples of sewing systems and methods that at least partially address some of the aforementioned drawbacks. Summary of the Invention

[0006] In a first aspect, a sewing system is provided. The sewing system includes a robot configured to move a piece of fabric, wherein the robot includes an end effector configured to hold the fabric piece. The system also includes a sewing machine configured to sew the fabric piece held by the end effector and including an electric motor. The system further includes a control unit configured to control the sewing operation of the sewing machine on the fabric piece. The control unit is configured to control the sewing operation by: receiving the speed and stitch spacing of the end effector; calculating a theoretical rotational speed of the electric motor of the sewing machine based on the speed and stitch spacing of the end effector; determining values ​​of operating parameters of the electric motor of the sewing machine related to the calculated theoretical rotational speed; and setting the operating parameters of the electric motor to the determined values ​​of the operating parameters.

[0007] This sewing system enables collaborative work between robots and sewing machines, thereby increasing the productivity of sewing operations on fabrics. Furthermore, the collaboration can be achieved using a relatively simple control unit, which reduces or even eliminates modifications or adaptations to the robot or sewing machine. Moreover, because adjustments can be reduced or even avoided, the overall system cost can remain relatively low compared to many dedicated automated sewing systems.

[0008] As described above, the control unit of this aspect can adjust the speed of the sewing machine by using the speed of the end effector as a reference, and accordingly set the operating parameters of the sewing machine's electric motor. These operations can involve relatively simple and straightforward algorithms. Relatively simple and straightforward algorithms can require relatively simple control units. Furthermore, the simplicity of the algorithm can reduce the number of electronic components required and reduce the risk of systematic errors caused by electronic malfunctions.

[0009] Because the control unit can avoid operating with relatively complex algorithms, the sewing system can achieve fast, flexible and efficient speed adjustments, thereby enhancing the collaboration between the sewing machine and the robot while minimizing delays and latency.

[0010] Unlike Cartesian sewing machines (which can be limited by their workspace and are not suitable for larger pieces of fabric), this system has no such limitations, making it suitable for fabric pieces of all sizes. This can mean a very flexible sewing system.

[0011] Furthermore, the robot in this sewing system is not limited to fabric transport, but can directly participate in the sewing operation.

[0012] Furthermore, this sewing system is compatible with sewing machines that have various feeding mechanisms, including feed dogs and specialized mechanisms such as embroidery mechanisms for free-motion sewing. It is also compatible with sewing machines that lack a feeding mechanism, such as those without feed dogs. The sewing system described in this disclosure can be integrated into a sewing device regardless of the presence of a feeding mechanism like feed dogs.

[0013] According to the first aspect, the sewing system can avoid the use of a vision system to control or monitor the sewing operation.

[0014] Given the above, the sewing system according to the first aspect can balance flexibility and cost. The sewing system can provide seamless integration between the robot and the sewing machine, which can improve performance.

[0015] In a second aspect, a method for controlling a sewing system is provided. The sewing system includes: a robot configured to move a piece of fabric, the robot including an end effector configured to hold the piece of fabric. The sewing system also includes a sewing machine configured to sew the piece of fabric held by the end effector, the sewing machine including an electric motor. The sewing system further includes a control unit configured to control the sewing operation of the sewing machine on the piece of fabric. To control the sewing system, the method includes: receiving, by the control unit, a speed and stitch spacing of the end effector; calculating, by the control unit, a theoretical rotational speed of the electric motor of the sewing machine based on the speed and stitch spacing of the end effector; determining, by the control unit, values ​​of operating parameters of the electric motor of the sewing machine related to the calculated theoretical rotational speed; and setting the operating parameters of the electric motor to the determined values ​​of the operating parameters by the control unit.

[0016] The benefits derived from this aspect can be similar to those mentioned regarding the first aspect.

[0017] In this disclosure, the velocity or position of the end effector in the robot can be defined relative to a reference point. The reference point can include the origin of a reference coordinate system. The reference coordinate system can be located inside or outside the robot's operating space. For example, a reference coordinate system can be established with its origin at the center point of the robot's base, or at another point inside or outside the operating space.

[0018] The speed or position of the end effector can be measured on the end effector or at a specific point or area associated with it. This specific point or area can serve as a representative marker of the movement or position of the entire end effector.

[0019] Furthermore, in this disclosure, the robot's tool center point (TCP) can be located at different locations. For example, it could be the location where the end effector or tool is attached, or in other examples, a location within the robot's wrist. The TCP could be located where a sewing machine needle pierces the fabric. Although the TCP can be defined at different locations in a coordinate system, for simplicity, in some examples of this disclosure, the TCP can represent the location where the end effector is attached and can serve as a reference for robot movement and calculation. The TCP can be located within a reference coordinate system.

[0020] In some cases, the reference point used to measure the speed or position of the end effector may include the tool center point. However, in some examples, the reference point used to measure the speed or position of the end effector may be different from the TCP.

[0021] Throughout this disclosure, the stitch spacing can be defined as the stitch length, or the distance between two consecutive stitches made by a sewing machine on a fabric piece.

[0022] Throughout this disclosure, the terms robot, industrial robot, and / or robotic arm are used interchangeably.

[0023] Throughout this disclosure, the term "fabric piece" can refer to one or more fabric pieces.

[0024] Throughout this disclosure, the rotational speed of the sewing machine's electric motor can refer to the revolutions per minute (RPM) of the electric motor driving the sewing machine. It determines the speed at which the needle moves up and down, directly affecting the sewing speed. Attached Figure Description

[0025] Non-limiting examples of this disclosure will now be described with reference to the accompanying drawings, in which:

[0026] Figure 1 A sewing system according to an example of this disclosure is schematically illustrated;

[0027] Figure 2 It is possible to do so according to an example of this disclosure. Figure 1 The diagram of the open-loop algorithm executed in the control unit of the sewing system;

[0028] Figure 3 A sewing system according to another example is illustrated schematically;

[0029] Figure 4 A perspective view of a robot and a sewing machine, based on another example, is illustrated schematically.

[0030] Figure 5 It is possible to do so according to an example of this disclosure. Figure 3 The closed-loop algorithm diagram executed in the control unit;

[0031] Figure 6 Another example of this disclosure is available. Figure 3 The closed-loop algorithm diagram executed in the control unit;

[0032] Figure 7 The control unit of a sewing system according to an example of this disclosure is schematically illustrated; and

[0033] Figure 8 This is a block diagram of a method for controlling a sewing system according to an example of this disclosure. Detailed Implementation

[0034] Figure 1A sewing system 1 according to an example of this disclosure is schematically illustrated. The sewing system may include an automated sewing system for at least partially manufacturing sewn products. Sewing system 1 includes a robot 2, a sewing machine 3, and a control unit 4. Robot 2 includes an end effector 6. End effector 6 is configured to hold a piece of fabric 5. Sewing machine 3 is configured to sew the piece of fabric 5 held by end effector 6. Control unit 4 is configured to control the sewing operation of sewing machine 3 on fabric 5. Sewing machine 3 includes an electric motor 31.

[0035] exist Figure 1 In the sewing system 1, a robot 2 is introduced to manipulate the fabric piece 5 by holding and / or moving it, while a sewing machine 3 can perform sewing operations on the fabric piece 5. In some examples, the end effector 6, and therefore the fabric piece 5, can move at least relative to the robot base or any other suitable reference point.

[0036] Robot 2 may include an industrial robot and / or a robotic arm having multiple programmable axes (i.e., rotational and / or linear degrees of freedom) between the robot base and the robot wrist. Each axis may have an associated drive element, such as a corresponding motor.

[0037] exist Figure 1 In the example, for clarity, the relationship between control unit 4 and robot 2 and / or sewing machine 3 is illustrated with dashed lines. This relationship may include networks, such as wired and / or wireless networks. In some cases, control unit 4 may communicate data with any other part of the system. In some examples, control unit 4 may be configured to control the power supply to the sewing machine. In this way, the rotation of electric motor 31 can be controlled in a relatively simple manner.

[0038] The control unit 4 can be configured to receive input data related to the operating parameters of the robot 2, process such input data, and generate corresponding output data related to the operating parameters of the sewing machine 4.

[0039] Figure 1 In the example, the sewing machine 3 is powered by an electric motor 31 to perform the sewing operation. Rotation of the electric motor 31 can cause rotation of the associated output shaft. Rotational movement can be converted into linear or rotational movement of different mechanisms of the sewing machine to perform the sewing operation.

[0040] The rotational speed of the electric motor 31 of the sewing machine 3 can refer to the revolutions per minute (RPM) of the electric motor 31 driving the sewing machine 3. The rotational speed of the electric motor 31 can usually be adjusted by changing operating parameters such as the power supply frequency and the duty cycle of the electric motor 31. The operating parameters of the sewing machine 3 can be determined by the control unit 4.

[0041] The rotational speed of the electric motor 31 is typically proportional to the sewing speed of the sewing machine 3. Sewing speed can be defined as the rate at which stitches are formed, and can be measured in stitches per minute (SPM). The sewing speed determines the speed at which the sewing process occurs.

[0042] As described above, the electric motor 31 can drive the mechanism of the sewing machine 3 to perform sewing operations. For example, stitches can be generated by the driving force applied by the electric motor 31. If the rotational speed of the electric motor 31 of the sewing machine 3 changes (whether increasing or decreasing), stitches can be generated at a higher or lower speed.

[0043] Meanwhile, the stitch spacing, which is the distance between the centers of consecutive stitches, affects the appearance and strength of the sewing. A smaller spacing results in tighter stitches, while a larger spacing results in wider gaps.

[0044] Figure 2 It is possible to do so according to an example of this disclosure. Figure 1 The diagram shows the open-loop algorithm executed in the control unit of the sewing system.

[0045] As described above, the control unit 4 is configured to control the sewing operation of the sewing machine 3 on the fabric 5. To this end, the control unit 4 is configured to receive the speed of the end effector 6. And pin spacing, based on the speed of end effector 6 The theoretical rotational speed ω of the electric motor 31 of sewing machine 3 is calculated based on the stitch spacing. SM_t Determine the theoretical rotational speed ω calculated. SM_t The values ​​of the operating parameters of the electric motor 31 of the sewing machine 3, and the values ​​of the operating parameters of the electric motor 31 as determined.

[0046] In this example, the speed of the end effector 6 can be defined relative to the origin of a reference coordinate system established within the operating space of robot 2. In some examples, the origin of the reference coordinate system can be established outside the operating space of robot 2. The origin and the reference coordinate system can be defined in various ways. For example, the origin can be set at the center point of the robot base, or in other cases, aligned with the center point of sewing machine 3. For user convenience, the origin can be set at other locations. Regardless of the selected reference point, the speed of the end effector 6 can be measured relative to the movement of the origin. Furthermore, this measurement can be performed at a specific point or area on the end effector 6, and this point or area can serve as a representative marker of the movement of the entire end effector. The speed of the end effector 6 can serve as a reference for the movement speed of the fabric piece 5. This speed can be expressed as the end effector speed. v ROB .

[0047] The speed of the end effector 6 can depend on the movement along the axes of robot 2, which defines its degrees of freedom. The combined speed along all axes determines the total end effector speed. Robot 2 includes a robot controller 21 (see...). Figure 3 In the case of [unclear context], robot controller 21 can calculate the end effector speed in milliseconds. This end effector speed value or data can be transmitted to control unit 4, which can help ensure smooth and delay-free sewing operations.

[0048] The speed of the end effector 6 can depend on a predetermined sewing pattern or sewing path. In a straight sewing pattern with uniform stitch spacing, the speed of the end effector can remain substantially constant or constant in the amplitude and / or direction followed by the end effector. For curved sewing patterns, the speed of the end effector can dynamically vary according to the amplitude and / or direction followed by the end effector based on the sewing pattern.

[0049] When the end effector 6 holds the fabric piece 5, the speed of the end effector 6 can be used as a reference to determine the moving speed of the fabric piece 5. The speed of the end effector 6 can be substantially the same as the moving speed of the fabric piece 5. Therefore, the end effector speed can be considered as the moving speed of the fabric piece 5. The movement of the fabric piece 5 can be defined relative to parts of the sewing system such as the needle.

[0050] When execution Figure 2 In the example, control unit 4 receives the end effector speed. v ROB And pin pitch. In some cases, control unit 4 can receive these two parameters via a user interface or external interface, a dedicated sensor, and / or predetermined stored instructions. Based on these two received parameters, i.e., end effector speed... v ROB And the stitch spacing, the control unit 4 calculates the theoretical speed ω of the electric motor 31 of the sewing machine 3. SM_t Control unit 4 can perform calculations following Equation 1 to determine the theoretical rotational speed ω. SM_t ,in f This represents the appropriate function used to perform the computation. Equation 1

[0051] The theoretical rotational speed ω of the electric motor 31 of sewing machine 3 is calculated. SM_t Then, control unit 4 determines the calculated velocity ω. SM_t The values ​​of the operating parameters of the electric motor 31 of the sewing machine 3. The calculated speed ω. SM_t It can correspond to the predetermined operating parameter values ​​of the electric motor 31.

[0052] The rotational speed of the electric motor 31 can be controlled, for example, by a frequency converter or any suitable device for changing the speed of the electric motor. The frequency converter can be configured to change the frequency of the power supplied to the electric motor. Changes in the frequency supply can change the rotational speed of the electric motor. Figure 2 In the example, the operating parameters of the sewing machine 3 include the power supply frequency of the electric motor 31 of the sewing machine 3. The frequency converter driver can be integrated with the electric motor 31 or can be separate from the electric motor. The control unit 4 can communicate with the frequency converter driver.

[0053] Once the operating characteristics of the electric motor 31 are defined, its rotational speed can be mathematically correlated with specific operating parameters. This correlation can be established either through real-time CPU calculations using numerical methods or by referring to a pre-defined lookup table (to reduce computation time). Figure 2 In the example, control unit 4 determines the calculated velocity ω according to the first lookup table 41. SM_t The values ​​of the relevant operating parameters of the electric motor 31 are stored in the first lookup table 41. The first lookup table stores a predetermined correspondence between the rotational speed of the electric motor 31 of the sewing machine 3 and the values ​​of the operating parameters. By adjusting these operating parameters, the rotational speed of the electric motor 31 can be modified accordingly.

[0054] When the supply frequency of the electric motor 31 is selected as an operating parameter, the first lookup table 41 can provide an array of rotational speeds and the corresponding power supply frequency values ​​for the electric motor 31 of the sewing machine 3. This is based on the theoretical rotational speed ω calculated by the control unit 4. SM_t The corresponding value of the power supply frequency of the electric motor 31 of the sewing machine 3 can be retrieved from the first lookup table 41. V .

[0055] Then, the control unit 4 sets the operating parameters of the electric motor 31 to the determined values. Figure 2 In the example, the power supply frequency of the electric motor 31 is set to a value. V This allows the rotational speed of the electric motor 31 to be changed to achieve the theoretical rotational speed ω. SM_t .

[0056] Figure 2 The open-loop algorithm is relatively simple and straightforward, allowing for fast response times and agile adjustments to the sewing machine's rotation speed without excessive delay or lag.

[0057] To maintain a substantially consistent level of stitch quality, the movement of the fabric piece 5, controlled by the robot 2, can be substantially simultaneous with or synchronized with the rotation of the electric motor 31 of the sewing machine 3. Misalignment will cause uneven fabric movement, resulting in irregular stitches or fabric deformation. Therefore, the control unit 4 can be configured to synchronize two speeds: the moving speed of the fabric piece 5 (i.e., the speed of the end effector 6) and the corresponding rotational speed of the electric motor 31 of the sewing machine 3.

[0058] The control unit 4 can use different algorithms to synchronize the speed of the end effector 6 with the rotational speed of the electric motor 31 of the sewing machine 3. Figure 2 The illustration shows the actions that are configured to be performed by control unit 4 during the execution of the open-loop algorithm according to this example.

[0059] Figure 3 A sewing system 1 according to another example is schematically illustrated, and Figure 4 A perspective view of a robot 2 and a sewing machine 4 according to an example is schematically illustrated. In these examples, a robot base 23 and a robot wrist 24 have been shown. Figure 3 In the example, for clarity, the relationship between control unit 4 and robot 2 and / or sewing machine 3 is illustrated with dashed lines. This relationship may include networks, such as wired and / or wireless networks.

[0060] exist Figure 3 In the example, sewing system 1 includes a robot controller 21. In some examples, robot controller 21 can be used to guide robot 2, enabling it to move at different speeds in multiple directions according to a desired sewing pattern. Robot controller 21 can perform calculations regarding robot operating parameters. Robot controller 21 can receive data related to robot operating parameters.

[0061] The end effector 6 may include a retainer 22 designed to hold and manipulate the fabric piece 5 for sewing and / or carrying. The retainer 22 may include a frame, clamp, etc. The retainer 22 may be attached to the robot 2 via a robotic wrist. Due to the low stiffness of the fabric material, the retainer 22 may be designed to firmly grip the fabric piece 5, allowing the fabric piece 5 to move with the retainer 22 under the guidance of the robot controller 21. The retainer 22 may be configured to grip the fabric piece 5, allowing the fabric piece 5 to remain substantially extended throughout the sewing operation. Various options are available to achieve the desired function of the retainer 22; that is, the shape, size, and / or general configuration can be adjusted according to each situation.

[0062] exist Figure 4In the example, retainer 22 includes a clamping frame that securely holds opposite sides of fabric piece 5 within the frame, ensuring stability and proper tension during operation. Sewing operations can be performed within the clamping area of ​​fabric piece 5. Figure 4 In this case, the TCP can be positioned at point 24 on the robot's wrist.

[0063] exist Figure 3 In the example, sewing machine 3 performs the sewing operation via needle 32. Needle 32 can move cyclically up and down. Each cycle of needle movement creates a stitch on the fabric piece 5. The rotational speed of electric motor 31 determines the speed at which needle 32 moves up and down.

[0064] The sewing machine 3 can also be equipped with a sensor 33 to measure the rotational speed of the electric motor 31. Different types of sensors 33 can be used. Figure 3 In the example, an encoder is used. When the encoder is an incremental encoder, a counter is connected to the encoder. In some examples, sensor 33 may include a speed or position sensor. Sensor 33 can communicate data with control unit 4.

[0065] Figure 3 The control unit 4 can use a closed-loop algorithm. Figure 5 The illustration shows an example of a closed-loop algorithm that can be applied to... Figure 3 An example of sewing system 1. Similar to... Figure 2 An example of an open-loop control algorithm, Figure 5 An example of control unit 4 can be used with two inputs (i.e., end effector speed). v ROB (and stitch spacing) Calculate the theoretical rotational speed ω of the electric motor 31 of sewing machine 3. SM_t Furthermore, the actual rotational speed ω of the electric motor 31 of the sewing machine 3... SM_m The actual rotational speed ω of the electric motor 31 can be measured by an encoder. SM_m This could be the speed at which the sewing machine performs the sewing operation. Control unit 4 can receive the measured speed ω. SM_m The actual rotational speed can correspond to the speed value measured by sensor 33 (e.g., an encoder).

[0066] exist Figure 5 In the example, control unit 4 is based on the calculated theoretical rotational speed ω SM_t The value of the operation parameter is retrieved from the first lookup table 41. V However, the value of this operation parameter V It is not used directly to set the rotation speed of the electric motor 31 of the sewing machine 3.

[0067] Control unit 4 can be based on speed error value Obtain the correction values ​​of the operating parameters of the electric motor 31 V Speed ​​error value This can involve the measured rotational speed. Compared with theoretical speed The difference between them. Speed ​​error value. The data can be sent to the corrector unit 42. The corrector unit 42 can be integrally formed with the control unit 4, or it can be formed separately. The corrector unit 42 can be configured to obtain a speed error corrector value. The speed error corrector value may include a measured value. V The change in value. In other words, the speed error corrector value can indicate the value... V The speed error corrector value can be based on the speed error value. A specific speed error corrector value can correspond to a specific speed error value. The speed error corrector value is determined by the term "corrector" in Equation 2 below. "Indicates the value of the calibration parameters for the electric motor 31." V According to Equation 2, where g1 represents the error used for execution. e SM,1 The appropriate function for calculation; g1 can implement the proportional-integral-derivative (PID) method. Equation 2

[0068] The corrected parameter values ​​can change the speed of the electric motor and can help to adjust the measured speed. Compared with theoretical speed convergence.

[0069] According to the example in Equation 2, the correction value of the operating parameter V Based on the retrieved value V The value is obtained from the speed error corrector. When the operating parameters include the power supply frequency, the value is retrieved. V Both the speed error correction value and the power supply frequency value are included.

[0070] Speed ​​error value It can be calculated in different ways. For example, in Equation 2, the velocity error value... The measured rotational speed of the electric motor 31 based on the sewing machine 3 and theoretical speed Calculation. In some cases, the speed error value... It can be based on the measured speed and theoretical speed (i.e., ω) of the electric motor 31 SM_t and ω SM_mThe difference between these values ​​is used to obtain the speed error corrector value.

[0071] In some examples, if the speed error value If the speed error threshold is not met, then the speed error value is... It is set to zero. Therefore, there is no speed correction.

[0072] In some cases, the speed error value By obtaining the measured rotational speed Compared with theoretical speed The speed error is calculated using past values ​​of the difference between the two values, and this past value can be integrated to produce the speed error value. The speed error corrector value can depend on the result of the integration.

[0073] In some other cases, the speed error value By obtaining the measured rotational speed Compared with theoretical speed The current rate of change of the difference between them is used for calculation. The slope of the rate of change can be obtained from g1 at a specific time point. The value of the velocity error corrector can depend on the slope of the rate of change.

[0074] Control unit 4 can set the operating parameters of electric motor 31 to the correction values ​​of the operating parameters. V In the example, the supply frequency of the electric motor 31 can be set using Equation 2. V .

[0075] Using this closed-loop algorithm, the measured rotational speed ω of the electric motor 31 of the sewing machine 3 can be monitored. SM_m And compare it with the theoretical rotational speed ω SM_t Compare them. When a difference is detected (i.e., ...), When the sewing machine 3 rotates, it can perform corrections to adjust the speed of the sewing machine 3, for example, in essentially real-time. This improves the synchronization between the movement of the fabric 5 and the sewing operation of the sewing machine 3. Furthermore, if a sewing error occurs, the system can quickly detect and correct the error, preventing or even reducing further sewing problems.

[0076] Therefore, it can be derived from Figure 3 The control unit 4 implements Figure 5 The closed-loop algorithm can help improve sewing quality.

[0077] Furthermore, the end effector speed is not the only behavioral parameter at the end effector. In some examples, the position of end effector 6 is another parameter to consider, and it can be used as a second parameter to enhance error correction in control unit 4. Therefore, another example of control unit 4 using a closed-loop algorithm is... Figure 6 As shown in the image. (and) Figure 5 Compared to the algorithm, Figure 6 The algorithm includes an additional feedback loop. This additional feedback loop will be explained below.

[0078] exist Figure 6 In the example, the absolute position of end effector 6 X ROB It can be controlled to synchronize with the rotational position of the electric motor 31 of the sewing machine 3. The control unit 4 can obtain the position data of the end effector 6 and can match this position data of the end effector 6 with the theoretical rotational position θ of the electric motor 31. SM_t Related. In other words, the position of the end effector 6 can correspond to a predetermined rotational position of the electric motor 31 and / or the output shaft of the electric motor during the sewing operation. To obtain the position data of the end effector 6, at least two options are available: 1) The control unit 4 can receive the absolute position of the end effector 6 through a user interface, a dedicated sensor, and / or predetermined stored instructions. X ROB 2) Control unit 4 controls the speed of the end effector during a predetermined duration of the sewing operation. v ROB Integrating to calculate the absolute position of the end effector X ROB The absolute position of the end effector 6 may include the absolute position of a point representing the end effector. Based on the received absolute position of the end effector 6... X ROB The theoretical rotational position θ of the electric motor 31 in the sewing machine 3 can be obtained. SM_t The two options for obtaining the position data of the end effector 6 are summarized in Equation 3 as follows: Equation 3

[0079] exist Figure 6 In the example, the control unit 4 receives the measured rotational position θ of the electric motor 31 of the sewing machine 3. SM_m The rotational position θ SM_m Various types of sensors can be used for measurement. In this example, the encoder is also used to measure the rotational position θ. SM_m If the encoder is an incremental encoder, a counter may also be required.

[0080] Control unit 4 can be based on the theoretical rotational position of electric motor 31 Measuring the rotational position of electric motor 31 To calculate the position error value Position error value Theoretical rotational position may be involved. With measurement of rotational position The difference between them. The correction value for the speed of electric motor 31. Based on theoretical rotational speed and by the “corrector” in Equation 4 below The position error corrector value is obtained by indicating the position error corrector value. The corrector unit 44 can be used to provide the position error corrector value. The corrector unit 44 can be integrally formed with the control unit 4, or it can be formed separately. The position error corrector value may include the theoretical rotational speed. The change in magnitude. The value of the specific position error corrector can refer to the specific position error value. The correction value ω of the rotational speed of the electric motor 31 of the sewing machine 3. SM_c This can be obtained from Equation 4, where g2 represents the expression used for execution. The appropriate function for calculation, such as the proportional-integral-derivative (PID) method: Equation 4

[0081] The correction value ω of the rotational speed of electric motor 31 SM_c It can change the speed of the electric motor and help adjust the theoretical rotational position of the electric motor 31. Measuring the rotational position of the electric motor 31 convergence.

[0082] Based on an example, the position error value It can be based on the theoretical rotational position of sewing machine 3 and the measured rotational position (i.e., θ). SM_t and θ SM_m The difference between these two values ​​is used to obtain the position error corrector value. Therefore, the position error corrector value can depend on this difference.

[0083] If the position error value If the position error threshold is not met, then the position error value is... It is set to zero. Therefore, there is no position correction.

[0084] In some cases, the function g2 can obtain the theoretical rotation position. With measurement of rotational position The difference between the past values ​​can be used as a reference, and the past values ​​can be integrated. The position error correction value can depend on the result of the integration.

[0085] In some other cases, the position error value The theoretical rotation position can be obtained. With measured rotational position The current rate of change of the difference between the two values. The slope of the rate of change can be obtained using the function g2 at a specific time point. The position error correction value can be generated based on the slope of the rate of change.

[0086] Control unit 4 can determine the correction value ω related to the rotational speed.SM_c The values ​​of the relevant operating parameters of the electric motor 31. In some examples, the control unit 4 determines the correction value ω for the rotational speed from the second lookup table 43. SM_c The second lookup table 43 can be similar to the first lookup table 41, and stores a predetermined correspondence between the correction values ​​of the sewing machine 3's rotational speed and the correction values ​​of the operating parameters. When the operating parameter is the supply frequency of the electric motor 31, the second lookup table 43 can be used to store the correction value ω of the rotational speed. SM_c and the value of supply frequency V Related. This supply frequency value V It is sent to the corrector unit 42, and is based on the theoretical speed of the electric motor 31 of the sewing machine 3 and the measured speed (i.e., ω). SM_t and ω SM_m The difference between the two values ​​is corrected to the value according to Equation 2. V The control unit 4 sets the power supply frequency of the electric motor 31 to a value. V .

[0087] In some examples, the first lookup table 41 and the second lookup table 43 can be formed as one unit, or they can be the same.

[0088] Figure 6 The example in the text can monitor both the rotational speed and rotational position of the electric motor 31 of the sewing machine 3, and detect the difference between the measured value and the theoretical value (i.e., and / or Corrections can be applied during this process. Therefore, sewing errors can be further reduced. For example... Figure 6 As shown, control unit 4 can integrate error correction for both rotational speed and rotational position, thereby improving the accuracy, stability, and adaptability of the dynamic system. By processing these two parameters simultaneously, more precise and efficient performance can be ensured. Furthermore, it helps minimize overshoot, improves overall control robustness, and better compensates for external disturbances. This enables control unit 4 to respond significantly and quickly to unexpected operational deviations in sewing machine 3.

[0089] According to one example of this disclosure, control unit 4 can control the operation of robot 2 according to a series of predetermined instructions in the form of an algorithm. The predetermined instructions may include operational and sewing instructions to produce sewn products in a substantially automated manner.

[0090] Robot 2 can be operated to pick up fabric piece 5 to be sewn. Fabric piece 5 can be fed to robot 2 manually or automatically. Fabric piece 5 can be held by retainer 22, which acts as an end effector. Robot 2 can feed fabric piece 5 to sewing machine 3 to sew fabric piece 5.

[0091] The robot controller 21 can command the robot to place the fabric piece 5 relative to the sewing machine to begin the sewing operation. The robot controller 21 can command the robot 2 to move the fabric piece 5 along a predetermined sewing path (such as a straight or curved sewing path). The end effector 6 can move in a predetermined direction at a predetermined speed. The control unit 4 can set or adjust the operating parameters of the electric motor to the determined operating parameters. The operating parameters can be determined according to any of the examples disclosed herein. The control unit 4 can control the sewing operation following any example of open-loop or closed-loop control discussed herein.

[0092] After the sewing operation is completed, robot 2 can be commanded to transport the sewn fabric piece 5 to the predetermined location.

[0093] If two or more fabric pieces 5 are to be sewn, the sewing operations can be substantially the same. The sewing path can be defined between the two or more fabric pieces 5 to join the fabric pieces together.

[0094] Figure 7 A schematic diagram illustrates a view of a control unit 4 of a sewing system according to an example of this disclosure. Control unit 4 may include a controller 45. Controller 45 may be a processor, chip, computing device, or processing resource that executes a sequence of machine-readable instructions contained in memory. Controller 45 performs operations on data. Memory may be a non-transitory machine-readable storage medium 46. Figure 7 As shown, a non-transitory machine-readable storage medium 46 is coupled to a controller 45. Examples of non-transitory machine-readable storage media may include storage devices, floppy disks, optical discs (CDs), digital multifunction discs (DVDs), USB drives, computer memory, read-only memory, or other devices capable of storing computer code.

[0095] Machine-readable instructions may include one or more computer programs in the form of source code, object code, intermediate code, and object code in the form of compiled code, or any other form suitable for implementing the methods and / or systems according to this disclosure. Machine-readable instructions may include the algorithms disclosed herein.

[0096] Control unit 4 can be an external control unit independent of both robot 2 and sewing machine 3. In some cases, control unit 4 can also be an integrated part of robot controller 21, thus providing a more cohesive and streamlined solution.

[0097] The feed mechanism in a sewing machine moves the fabric piece under the needle at a precise rate. The feed dog mechanism is a common feed system widely used in many sewing machines. It synchronizes the movement of the fabric piece with the up-and-down movement of the needle. When the needle rises, the feed dog rises and propels the fabric piece forward, while when the needle falls, the feed dog lowers to avoid interference. In contrast, the mending mechanism disables the feed dog (if present), enabling free-motion sewing where the user can manually move the fabric piece in any direction while the needle is sewing. In the example above, the fabric piece 5 is moved by the robot 2. Therefore, the sewing system 1 can be compatible with sewing machines equipped with or without a feed dog mechanism. For example, the sewing machine 3 may include a mending mechanism. The sewing system 1 can be implemented regardless of the presence or absence of a feed mechanism.

[0098] The movement of the fabric piece 5 driven by the robot 2 can be kept uninterrupted throughout the sewing process, or paused when the needle 32 pierces the fabric piece 5 and resumed once the needle is removed.

[0099] While the sewing system 1 is versatile and applicable to a wide range of textile applications, it is well-suited for sewing automotive textiles such as seat covers, airbags, seat belts, and more. Textile products can be sewn using 2D, 3D, or a combination of both patterns. 2D sewing patterns are flat, two-dimensional templates used to guide the cutting and assembly of fabric pieces. These patterns represent the product in its unassembled, flat state. In contrast, 3D sewing patterns capture the shape and dimensions of the final product in three-dimensional space. These patterns are typically created using 3D modeling or virtual prototyping techniques.

[0100] Figure 8 This is a block diagram of a method 600 for controlling a sewing system according to an example of this disclosure. Method 600 can be applied to any of the sewing systems 1 disclosed herein.

[0101] In block 610, control unit 4 receives the end effector speed. v ROB And pin spacing. This can be done as discussed in this article.

[0102] Control unit 4 is based on two parameters received in block 610 (i.e., end effector speed). v ROB Calculate the theoretical rotational speed ω of the sewing machine's electric motor (including stitch spacing). SM_t As shown in block 620. The theoretical rotational speed ω SM_t It can be the desired speed value corresponding to the two received parameters.

[0103] In block 630, control unit 4 determines the theoretical speed ω. SM_tThe values ​​of the operating parameters for the electric motor of the sewing machine. These operating parameter values ​​can correspond to the desired speed values ​​of the end effector.

[0104] In some examples, block 630 may include: the control unit obtaining the value of the operating parameter from a first lookup table. The first lookup table may store a predetermined correspondence between the sewing machine's rotational speed and the value of the operating parameter.

[0105] In some examples, the operating parameters mentioned in block 630 may include the power supply frequency of the sewing machine's electric motor.

[0106] In block 640, the control unit sets the operating parameters of the electric motor to the values ​​of the operating parameters determined in block 630.

[0107] Method 600 may include, for example, Figure 5 Another feature of the system example shown. Because Figure 5 Examples include closed-loop configurations, so with... Figure 5 The characteristics of the relevant method can also imply a closed-loop configuration. Therefore, the method may include receiving a measured rotational speed ω of the electric motor 31 of the sewing machine from the control unit 4. SM_m The control unit 4 can be based on the measured rotational speed of the electric motor 31 of the sewing machine 3. and theoretical speed To calculate the speed error value Speed ​​error value This can be calculated based on any of the examples discussed in this article. Then, control unit 4 can base its calculations on the speed error value. Correction values ​​for the operating parameters of the electric motor 31 are obtained. These correction values ​​can be obtained according to any of the examples disclosed herein. The correction values ​​for the operating parameters of the electric motor can be used as a reference for setting the operating parameters of the electric motor and changing its speed. The correction of the operating parameters can be calculated based on feedback from the sewing machine 3. In this example, the feedback may include the measured rotational speed ω of the electric motor 31. SM_m .

[0108] In some examples, method 600 may include, for example, Figure 6 Another feature of the system example shown. Because Figure 6 Examples include closed-loop configurations, so with... Figure 6 The characteristics of the relevant method can also imply a closed-loop configuration. Therefore, the method may include obtaining position data of the end effector by the control unit 4. The position data of the end effector can be obtained according to any of the examples discussed herein. The control unit 4 can then compare the obtained position data with the theoretical rotational position θ of the electric motor. SM_t Related. Theoretical rotational position θ SM_tThis corresponds to the expected rotational position of the electric motor 31. The control unit 4 can receive the measured rotational position θ of the electric motor. SM_m The control unit 4 can be based on the theoretical rotational position of the electric motor 31. Measuring the rotational position of electric motor 31 To calculate the position error value Position error value The calculation can be performed based on any of the examples discussed herein. The method may also include calculation by control unit 4 based on theoretical rotational speed. and position error value Obtain the correction value of the rotational speed of electric motor 31 Correction value for the rotational speed of electric motor 31 The correction values ​​can be obtained according to any of the examples disclosed herein. The obtained correction values ​​can be used as a reference for setting the operating parameters of the electric motor and changing its speed. The correction of the operating parameters can be calculated based on feedback from the sewing machine. In this example, the feedback includes the measured rotational speed and measured rotational position of the electric motor.

[0109] In some examples, obtaining the position data of the end effector may include receiving the absolute position of the end effector from an external interface of the robot by the control unit. The position data of the end effector can also be obtained by the control unit by controlling the speed of the end effector during a predetermined duration of the sewing operation. v ROB Perform integration calculations. The absolute position of the end effector can include the absolute position of a point representing the end effector. The robot's external interface can be an interface that allows external entities to provide the absolute position.

[0110] In some examples, the correction values ​​for the operating parameters can be obtained by the control unit from a second lookup table. The second lookup table can store a predetermined correspondence between the correction values ​​for the sewing machine's rotational speed and the correction values ​​for the operating parameters.

[0111] According to some examples, method 600 may include operating robot 2 to pick up or hold fabric piece 5 and feeding fabric piece 5 to sewing machine 3 to sew fabric piece 5.

[0112] Method 600 may also include moving the fabric piece 5 along a predetermined sewing path. If two or more pieces of fabric are to be sewn together, these pieces of fabric may also be moved together. The sewing machine 4 may be operated to perform the sewing operation. The speed of the electric motor 31 of the sewing machine 4 may be set or adjusted according to any of the examples discussed herein.

[0113] Method 600 may include a control unit 4 commanding a robot to transport the sewn fabric piece 5 to a predetermined location. The predetermined location may be a station within the manufacturing facility. The sewing may be completed or may require further processing.

[0114] Although only a few examples have been disclosed herein, other alternatives, modifications, uses, and / or equivalents of this disclosure are possible. The scope of this disclosure should not be limited to the specific examples, but should be determined solely by a reasonable interpretation of the appended claims.

[0115] The reference numerals in the accompanying drawings are placed in parentheses in the claims merely to increase comprehensibility and should not be construed as limiting the scope of the claims.

Claims

1. A sewing system (1), comprising: Robot (2), the robot being configured to move fabric piece (5), wherein the robot includes an end effector (6) configured to hold the fabric piece (5); Sewing machine (3), the sewing machine being configured to sew the fabric piece (5) held by the end effector (6), wherein the sewing machine includes an electric motor (31); and Control unit (4), the control unit being configured to control the sewing operation of the sewing machine (3) on the fabric piece (5) in the following manner: The speed of receiving the end effector (6) ) and stitch spacing; Based on the speed of the end effector (6) The theoretical rotational speed of the electric motor (31) is calculated using the pin spacing and the pin pitch. ); Determine the calculated theoretical rotational speed ( The values ​​of the operating parameters of the electric motor (31) related to this; as well as Set the operation parameter to the determined value of the operation parameter.

2. The sewing system (1) according to claim 1, wherein the control unit (4) is configured to control the sewing operation in such a way as: Receives the measured rotational speed (SJ) of the electric motor (31) ); Based on the measured rotational speed ( ) and the theoretical rotational speed ( ) Calculate the speed error value ( ); Based on the speed error value ( Obtain the correction value of the operating parameters; Set the operating parameter to the correction value of the operating parameter.

3. The sewing system (1) according to claim 1, wherein the control unit (4) is configured to control the sewing operation in the following manner: Determine the calculated theoretical rotational speed from the first lookup table (41). The values ​​of the operating parameters related to the first lookup table (41) are stored in the first lookup table (41) which stores a predetermined correspondence between the rotation speed of the sewing machine (3) and the values ​​of the operating parameters.

4. The sewing system (1) according to any one of claims 1 to 2, wherein the control unit (4) is configured to control the sewing operation in such a way as: Obtain the position data of the end effector (6); Compare the position data with the theoretical rotational position of the electric motor ( Related to; Receive the measured rotational position of the electric motor (31) ); Based on the theoretical rotation position ( ) and the measured rotational position ( ) Calculate the position error value ( ); Based on the theoretical rotational speed ( ) and the position error value ( ) to obtain the correction value of the rotational speed ( ); The correction value based on the said rotational speed ( The correction values ​​of the operating parameters are obtained.

5. The sewing system (1) according to claim 4, wherein the control unit (4) is configured to control the sewing operation in such a way as: The correction value of the operating parameter is determined from the second lookup table (43), wherein the second lookup table (43) stores a predetermined correspondence between the correction value of the rotation speed of the sewing machine (3) and the correction value of the operating parameter.

6. The sewing system (1) according to any one of the preceding claims, wherein the operating parameters include the power supply frequency of the electric motor (31).

7. The sewing system (1) according to any one of the preceding claims, wherein the control unit (4) is an integrated part of an external control unit or a robot controller (21).

8. A method for controlling a sewing system (1), wherein the sewing system (1) comprises: Robot (2), the robot being configured to move fabric piece (5), wherein the robot includes an end effector (6) configured to hold the fabric piece (5); A sewing machine (3) configured to sew the fabric piece (5) held by the end effector (6), wherein the sewing machine (3) includes an electric motor (31); and Control unit (4), the control unit being configured to control the sewing operation of the sewing machine (3) on the fabric piece (5); The method includes: The speed of the end effector (6) is received by the control unit (4). ) and stitch spacing; The control unit (4) determines the speed of the end effector (6) based on the speed of the end effector (6). The theoretical rotational speed of the electric motor (31) is calculated using the pin spacing and the pin pitch. ); The control unit (4) determines the calculated theoretical rotational speed ( The values ​​of the operating parameters of the electric motor (31) related to this; and The control unit (4) sets the operating parameters to the determined values ​​of the operating parameters.

9. The method of claim 8, comprising: The control unit (4) receives the measured rotational speed (SSR) of the electric motor (31). ); The control unit (4) bases its calculations on the measured rotational speed ( ) and the theoretical rotational speed ( ) Calculate the speed error value ( ); The control unit (4) bases its decisions on the speed error value ( Obtain the correction value of the operating parameters; The control unit (4) sets the operating parameter to the correction value of the operating parameter.

10. The method of claim 8, wherein determining the value of the operating parameter comprises: The control unit (4) obtains the value of the operating parameter from a first lookup table (41), wherein the first lookup table (41) stores a predetermined correspondence between the rotation speed of the sewing machine (3) and the value of the operating parameter.

11. The method according to any one of claims 8 to 9, comprising: The position data of the end effector (6) is obtained by the control unit (4); The control unit (4) compares the position data of the end effector (6) with the theoretical rotational position of the electric motor (31). Related to; The control unit (4) receives the measured rotational position of the electric motor (31). ); The control unit (4) is based on the theoretical rotation position ( ) and the measured rotational position ( ) Calculate the position error value ( ); The control unit (4) is based on the theoretical rotational speed ( ) and the position error value ( ) to obtain the correction value of the rotational speed ( ); The control unit (4) uses the correction value based on the rotational speed ( The correction values ​​of the operating parameters are obtained.

12. The method of claim 11, wherein obtaining the position data of the end effector (6) comprises: The control unit (4) controls the speed of the end effector (6) during a predetermined duration of the sewing operation. The absolute position of the end effector is calculated by integrating the components. ).

13. The method of claim 11, wherein obtaining the position data of the end effector (6) comprises: The control unit (4) receives the absolute position of the end effector (6) from the external interface of the robot (2). ).

14. The method according to any one of claims 11 to 13, wherein determining the correction value of the operating parameter comprises: The control unit (4) obtains the correction value of the operating parameter from the second lookup table (43), wherein the second lookup table (43) stores a predetermined correspondence between the correction value of the rotation speed of the sewing machine (3) and the correction value of the operating parameter.

15. The method according to any one of claims 8 to 14, wherein the operating parameters include the power supply frequency of the electric motor (31).

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