Industrial sewing machine rotating speed loop control method, device and equipment and storage medium

Abstract

The invention discloses a rotating speed loop control method, device and equipment of an industrial sewing machine and a storage medium, which are applied to the field of control, and comprise the following steps: pre-establishing a mapping table of different rotating speeds and optimal control parameters; the optimal control parameters comprise an optimal proportional control parameter and an optimal integral control parameter; acquiring the actual rotating speed of the servo motor of the industrial sewing machine through a photoelectric encoder, filtering the actual rotating speed, and obtaining an absolute value to obtain an effective actual rotating speed; querying the mapping table by taking the effective actual rotating speed as an index to obtain a target proportional control parameter and a target integral control parameter; and performing proportional-integral adjustment on the deviation between the target rotating speed and the effective actual rotating speed value through a rotating speed loop controller based on the target proportional control parameter and the target integral control parameter, and outputting a control quantity to drive a servo motor. According to the method, the rotating speed control precision and the running smoothness under different sewing tasks are improved; real-time complex operation is not needed, and the operation load of the controller and the engineering implementation cost are greatly reduced.

Description

Technical Field

[0001] This invention relates to the field of control, and in particular to a method, apparatus, equipment and storage medium for controlling the rotational speed loop of an industrial sewing machine. Background Technology

[0002] Industrial sewing machines are devices with extremely high dynamic performance requirements. Their servo motors need to operate over a wide speed range and frequently experience transient processes such as starting, stopping, accelerating, and decelerating. Different sewing tasks, such as high-speed straight sewing, complex pattern sewing, and sewing on thick or elastic fabrics, place drastically different demands on the motor's speed response and stability. Currently, industrial sewing machines commonly use traditional fixed-parameter PI (proportional-integral) controllers as the core control algorithm for the speed loop. However, fixed-parameter PI controllers make it difficult for the control system to maintain optimal control accuracy consistently under wide speed ranges and nonlinear loads. Adaptive control algorithms (such as model reference adaptation and fuzzy control) can theoretically solve these problems, but their algorithms are complex, computationally intensive, difficult to implement in engineering, and costly, making them difficult to widely apply in industrial sewing machine products that require high cost-effectiveness and fast response.

[0003] Therefore, how to provide a low-cost, high-precision adaptive control method for the speed loop of industrial sewing machines is a technical problem that urgently needs to be solved. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a method, device, equipment and storage medium for controlling the speed loop of an industrial sewing machine, which solves the problems of high cost and complex calculation in the adaptive control of the speed loop of an industrial sewing machine in the prior art.

[0005] To solve the above-mentioned technical problems, the present invention provides a method for controlling the rotational speed loop of an industrial sewing machine, comprising:

[0006] A mapping table between different speeds and optimal control parameters is pre-established; the optimal control parameters include optimal proportional control parameters and optimal integral control parameters.

[0007] The actual speed of the servo motor of the industrial sewing machine is obtained by using a photoelectric encoder. The actual speed is then filtered and its absolute value is taken to obtain the effective actual speed.

[0008] The target proportional control parameters and target integral control parameters are obtained by querying the mapping table using the effective actual speed as the index.

[0009] The speed loop controller adjusts the deviation between the target speed and the effective actual speed value using proportional-integral adjustment based on the target proportional control parameters and the target integral control parameters, and outputs a control quantity to drive the servo motor.

[0010] Optionally, a mapping table between different speeds and optimal control parameters is pre-established, including:

[0011] Using a dynamometer to simulate the actual load, the servo motor is controlled to maintain stable operation at multiple discrete constant speed points under different load conditions;

[0012] For each discrete constant speed point, the optimal proportional control parameter and the optimal integral control parameter with the fastest system response and the overshoot less than a preset threshold are selected by the operating condition tuning method.

[0013] Each discrete constant speed point and its corresponding optimal proportional control parameter and optimal integral control parameter are recorded in the mapping table.

[0014] Optionally, the discrete constant speed point is the speed value corresponding to the straight seam, pattern seam, and thick material seam of the industrial sewing machine.

[0015] Optionally, the target proportional control parameters and target integral control parameters are obtained by querying the mapping table using the effective actual speed as an index, including:

[0016] If the effective actual speed value completely matches any discrete constant speed point in the mapping table, then the optimal proportional control parameter and the optimal integral control parameter corresponding to the discrete constant speed point are used as the target proportional control parameter and the target integral control parameter.

[0017] If the effective actual speed value is within the range of discrete constant speed points in the mapping table, then the two adjacent discrete constant speed points corresponding to the effective actual speed value are located by binary search. Based on the optimal proportional control parameter and the optimal integral control parameter corresponding to the two adjacent discrete constant speed points, the target proportional control parameter and the target integral control parameter are calculated by linear interpolation.

[0018] Optionally, it also includes:

[0019] If the effective actual speed value is less than the minimum value of the discrete constant speed points in the mapping table, then the optimal proportional control parameter and the optimal integral control parameter corresponding to the minimum value are respectively used as the target proportional control parameter and the target integral control parameter;

[0020] If the effective actual speed value is greater than the maximum value of the discrete constant speed points in the mapping table, then the optimal proportional control parameter and the optimal integral control parameter corresponding to the maximum value are respectively used as the target proportional control parameter and the target integral control parameter.

[0021] Optionally, if the effective actual speed value is within the range of discrete constant speed points in the mapping table, then two adjacent discrete constant speed points corresponding to the effective actual speed value are located using a binary search method. Based on the optimal proportional control parameter and the optimal integral control parameter corresponding to the two adjacent discrete constant speed points, the target proportional control parameter and the target integral control parameter are calculated using a linear interpolation method, including:

[0022] Step 1: Initialize the discrete constant speed point array with the starting index 0 and the ending index 1 minus the array length, and calculate the midpoint of the index;

[0023] Step 2: Compare the effective actual speed value with the discrete constant speed point corresponding to the index value mid. If the effective actual speed value is less than the discrete constant speed point corresponding to the index value mid, then update the end index to mid-1. If the effective actual speed value is greater than the discrete constant speed point corresponding to the index value mid, then update the initial index to mid+1.

[0024] Step 3: Repeat step 2 until the starting index is greater than the ending index, and take the discrete constant speed points corresponding to the current ending index and the starting index as the two adjacent discrete constant speed points corresponding to the effective actual speed value;

[0025] Step 4: Based on the optimal proportional control parameters and optimal integral control parameters corresponding to the two adjacent discrete constant speed points, calculate the target proportional control parameters and the target integral control parameters using linear interpolation; the calculation formula for the linear interpolation method is: ;

[0026] Where X is the effective actual speed value, X1 and X2 are two adjacent discrete constant speed points obtained by positioning, Y1 is the optimal proportional control parameter or optimal integral control parameter corresponding to X1, Y2 is the optimal proportional control parameter or optimal integral control parameter corresponding to X2, and Y is the target proportional control parameter or target integral control parameter corresponding to the effective actual speed value.

[0027] Optionally, after establishing a mapping table between different speeds and optimal control parameters in advance, the following is also included:

[0028] During system operation, the speed fluctuation value of the servo motor is monitored in real time. When the speed fluctuation value exceeds the preset fluctuation threshold for a preset number of consecutive preset times, the parameter retuning process is triggered, and the optimal control parameters obtained by retuning are added to the mapping table.

[0029] The present invention also provides an industrial sewing machine speed ring control device, comprising:

[0030] The mapping table construction module is used to pre-build mapping tables between different speeds and optimal control parameters; the optimal control parameters include optimal proportional control parameters and optimal integral control parameters.

[0031] The speed processing module is used to obtain the actual speed of the industrial sewing machine servo motor through a photoelectric encoder, filter the actual speed and take the absolute value to obtain the effective actual speed.

[0032] The query module is used to query the mapping table using the effective actual speed as an index to obtain the target proportional control parameters and the target integral control parameters;

[0033] The control module is used to adjust the deviation between the target speed and the effective actual speed value using a speed loop controller based on the target proportional control parameters and the target integral control parameters, and output a control quantity to drive the servo motor.

[0034] The present invention also provides an industrial sewing machine speed ring control device, comprising:

[0035] Memory, used to store computer programs;

[0036] A processor is used to implement the industrial sewing machine speed loop control method described above when executing the computer program.

[0037] The present invention also provides a computer-readable storage medium storing computer-executable instructions, which, when loaded and executed by a processor, implement the industrial sewing machine speed loop control method described above.

[0038] As can be seen, this invention establishes a mapping table between different speeds and optimal control parameters in advance; the optimal control parameters include optimal proportional control parameters and optimal integral control parameters; the actual speed of the industrial sewing machine servo motor is obtained through a photoelectric encoder, the actual speed is filtered and its absolute value is taken to obtain the effective actual speed; the mapping table is queried using the effective actual speed as an index to obtain the target proportional control parameters and target integral control parameters; through a speed loop controller, based on the target proportional control parameters and target integral control parameters, the deviation between the target speed and the effective actual speed value is proportionally and integrally adjusted, and the control quantity is output to drive the servo motor. The beneficial effects of this invention are as follows: Addressing the transient demands of industrial sewing machines operating across a wide speed range and undergoing frequent starts, stops, accelerations, and decelerations, as well as the differentiated control requirements of various working conditions such as high-speed straight-line sewing, complex pattern sewing, and sewing of thick or elastic fabrics, this invention pre-establishes a mapping table between speed and optimal PI control parameters. Combined with photoelectric encoder speed detection, absolute value filtering, and table lookup interpolation for parameter matching, it overcomes the shortcomings of traditional fixed-parameter PI controllers that rely on a single parameter to adapt to all working conditions. This ensures the system maintains optimal control across the entire speed range, effectively improving the control accuracy and smoothness of motor speed under different sewing tasks and guaranteeing stitch uniformity. Furthermore, compared to complex adaptive algorithms such as model reference adaptation and fuzzy control, this method employs lightweight control logic using offline calibration and online table lookup interpolation. It eliminates the need for real-time complex parameter optimization calculations, significantly reducing the computational load on the servo motor controller. This achieves a leap in control performance without increasing hardware costs, avoiding the difficulties and high costs associated with complex algorithm engineering implementation. This aligns perfectly with the high-performance, cost-effective, and fast-response product positioning of industrial sewing machines, demonstrating significant value for industrialization and promotion.

[0039] In addition, the present invention also provides an industrial sewing machine speed ring control device, equipment and storage medium, which also have the above-mentioned beneficial effects. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0041] Figure 1 A flowchart of an industrial sewing machine speed loop control method provided in an embodiment of the present invention;

[0042] Figure 2 This is an example flowchart of a search algorithm provided in an embodiment of the present invention;

[0043] Figure 3A flowchart illustrating an example of an interval query method provided in an embodiment of the present invention;

[0044] Figure 4 A flowchart illustrating an industrial sewing machine speed loop control method provided in an embodiment of the present invention;

[0045] Figure 5 This is a schematic diagram of the structure of an industrial sewing machine speed ring control device provided in an embodiment of the present invention;

[0046] Figure 6 This is a schematic diagram of the structure of an industrial sewing machine speed ring control device provided in an embodiment of the present invention. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0048] Industrial sewing machines are devices with extremely high dynamic performance requirements. Their servo motors need to operate over a wide speed range and frequently experience transient processes such as starting, stopping, accelerating, and decelerating. Different sewing tasks, such as high-speed straight sewing, complex pattern sewing, and sewing on thick or elastic fabrics, place drastically different demands on the motor's speed response and stability. Currently, industrial sewing machines generally use traditional fixed-parameter PI (proportional-integral) controllers as the core control algorithm for the speed loop. However, fixed-parameter PI controllers have inherent limitations: their parameters are typically tuned at a specific speed point, such as the rated speed, to optimize performance. This makes it difficult for the control system to maintain optimal control accuracy over a wide speed range and under nonlinear loads. Specifically, at high speeds, parameter settings tend to be conservative in pursuit of stability, resulting in slow dynamic response and an inability to meet the rapid start-stop requirements of high-speed sewing. At low speeds, the parameters cannot provide sufficient gain, leading to unstable torque output, especially when sewing thick materials or handling elastic fabrics, which can easily cause needle jamming, thread breakage, or uneven stitches. When faced with nonlinear disturbances, such as the instantaneous load change when the needle pierces multiple layers of fabric, the fixed-parameter PI controller cannot quickly adapt and adjust, easily causing speed drops or steady-state errors, affecting sewing quality. Advanced adaptive control algorithms, such as model reference adaptation and fuzzy control, can theoretically solve this problem, but their algorithms are complex, computationally intensive, difficult to implement in engineering, and costly, making them difficult to widely apply in industrial sewing machine products that require high cost-effectiveness and rapid response.

[0049] To address the shortcomings of existing fixed-parameter PI control in terms of accuracy, and the problems of high computational complexity, difficulty in implementation, and high cost of existing adaptive control algorithms, this invention provides a speed loop control method for industrial sewing machines. This method has low computational complexity, is easy to implement in engineering, and can significantly improve the control performance of industrial sewing machines under all operating conditions.

[0050] Please refer to the details. Figure 1 , Figure 1 A flowchart illustrating a speed loop control method for an industrial sewing machine, provided as an embodiment of the present invention. The method may include:

[0051] S101: A mapping table between different speeds and optimal control parameters is pre-established; the optimal control parameters include the optimal proportional control parameter (proportional gain Kp) and the optimal integral control parameter (integral gain). ).

[0052] The execution subject in this embodiment is a terminal. This embodiment does not limit the type of terminal, as long as it can perform the operation of the industrial sewing machine speed loop control method. This step is an offline calibration process to obtain a mapping table. The mapping table in this embodiment is in the form of a two-dimensional array, such as [motor speed, corresponding Kp / Ki]. The first column represents different speeds, and the second column represents their corresponding optimal control parameters. The mapping table can also be understood as a speed loop PI parameter mapping model, which is stored in the controller's non-volatile memory. This embodiment does not specifically limit the construction process of the mapping table; for example, each speed may correspond to one optimal control parameter, or each speed range may correspond to one optimal control parameter, or a commonly used fixed speed may correspond to one optimal control parameter.

[0053] Furthermore, to improve efficiency and storage space, the aforementioned pre-established mapping table of different speeds and optimal control parameters can include: using a dynamometer to simulate actual loads, controlling the servo motor to maintain stable operation at multiple discrete constant speed points under different load conditions; for each discrete constant speed point, selecting the optimal proportional control parameter and optimal integral control parameter with the fastest system response and overshoot less than a preset threshold using a working condition tuning method; and recording each discrete constant speed point and its corresponding optimal proportional control parameter and optimal integral control parameter in the mapping table. This embodiment does not specifically limit the preset threshold; for example, it could be 2% or 5%. This implementation uses a dynamometer to simulate diverse load conditions during actual sewing by an industrial sewing machine, essentially verifying the robustness of the parameters. It ensures that the calibrated PI parameters can meet the requirements of fastest response and overshoot less than the threshold under different loads, avoiding the problem of control instability during actual sewing (such as switching between thin and thick materials) if the parameters only adapt to a single load condition. Combining parameter tuning at multiple discrete constant speed points ensures that the calibrated PI parameters are fully adapted to real-world operating scenarios. Meanwhile, by using the fastest system response and overshoot less than a preset threshold as dual indicators to select the optimal parameters, the problem of control performance imbalance caused by single indicator tuning is effectively avoided. The resulting speed-optimal control parameter mapping table provides accurate and reliable parameter support for subsequent online lookup control. This ensures the smooth operation and response speed of the servo motor across the entire speed range and under different sewing loads, while avoiding the computational overhead of online parameter optimization, thus improving the robustness and engineering practicality of the control system.

[0054] Furthermore, the aforementioned discrete constant speed points correspond to the speed values ​​for straight seams, pattern seams, and thick-material seams on industrial sewing machines. This embodiment directly maps these discrete constant speed points to the actual speed values ​​of typical operating modes such as straight seams, pattern seams, and thick-material seams on industrial sewing machines. This ensures that the offline parameter tuning process accurately anchors to the actual usage scenarios of the equipment, avoiding parameter redundancy or insufficient adaptability caused by indiscriminate selection of speed points. The optimal PI control parameters calibrated in this way can directly match the speed control requirements of different sewing modes, significantly improving the smoothness of high-speed operation of straight seams, the response speed of speed switching in pattern seams, and the stability of low-speed, high-torque operation in thick-material seams. This ensures that the mapping table can quickly retrieve suitable parameters in practical applications, further enhancing the practicality and specificity of the control system, while reducing the workload of calibrating invalid speed points and improving offline tuning efficiency.

[0055] S102: Obtain the actual speed of the industrial sewing machine servo motor through a photoelectric encoder, filter the actual speed and take the absolute value to obtain the effective actual speed.

[0056] This embodiment acquires the actual speed of the servo motor in real time through a photoelectric encoder, and filters the actual speed to effectively eliminate interference noise during motor operation and signal transmission. This avoids parameter lookup deviations and sudden changes in control quantities caused by speed signal fluctuations, and improves the smoothness of speed feedback. Taking the absolute value of the filtered speed can unify the speed index standard in both forward and reverse motor states, ensuring that the optimal PI parameter in the mapping table can be accurately looked up based on the effective speed value regardless of the motor's direction of rotation. This lays the foundation for precise adjustment of the subsequent speed loop, and ultimately ensures the stability and consistency of speed control in industrial sewing machines under different sewing modes.

[0057] S103: Use the effective actual speed as an index to look up the mapping table and obtain the target proportional control parameters and target integral control parameters.

[0058] This step, based on the effective actual speed obtained in step S102, queries and matches the mapping table pre-built in step S101 to determine the target proportional control parameter and target integral control parameter corresponding to the current effective actual speed. This embodiment does not specifically limit the search method. For example, it could be a one-to-one comparison; or it could be an interval comparison.

[0059] Furthermore, the above-mentioned querying of the mapping table using the effective actual speed as an index to obtain the target proportional control parameters and target integral control parameters may include:

[0060] If the effective actual speed value perfectly matches any discrete constant speed point in the mapping table, then the optimal proportional control parameter and the optimal integral control parameter corresponding to the discrete constant speed point are taken as the target proportional control parameter and the target integral control parameter.

[0061] If the effective actual speed value is within the range of discrete constant speed points in the mapping table, then the two adjacent discrete constant speed points corresponding to the effective actual speed value are located by binary search. Based on the optimal proportional control parameter and the optimal integral control parameter corresponding to the two adjacent discrete constant speed points, the target proportional control parameter and the target integral control parameter are calculated by linear interpolation.

[0062] If the effective actual speed value is less than the minimum value of the discrete constant speed points in the mapping table, then the optimal proportional control parameter and the optimal integral control parameter corresponding to the minimum value are used as the target proportional control parameter and the target integral control parameter, respectively; if the effective actual speed value is greater than the maximum value of the discrete constant speed points in the mapping table, then the optimal proportional control parameter and the optimal integral control parameter corresponding to the maximum value are used as the target proportional control parameter and the target integral control parameter, respectively.

[0063] Specifically, you can refer to Figure 2 , Figure 2This is a flowchart illustrating a search algorithm provided in an embodiment of the present invention. First, the variables used in the process (such as input speed buffers, index identifiers in the mapping table, intermediate variables for parameter calculation, etc.) are initialized. The validity of the actual speed value is determined, ensuring it falls within the coverage of the mapping table. If it is not within the range, the optimal proportional control parameter and optimal integral control parameter corresponding to the nearest discrete constant speed point in the mapping table are output. If it is within the range and a complete match is found, the optimal proportional control parameter and optimal integral control parameter corresponding to the matched discrete constant speed point are output. If there is no complete match, a binary search is used to continuously narrow the search interval, and finally, a linear interpolation method is used to output the result. The linear interpolation method ensures smooth parameter transitions and avoids speed fluctuations caused by operating condition changes.

[0064] Furthermore, if the effective actual speed value falls within the range of discrete constant speed points in the mapping table, then the two adjacent discrete constant speed points corresponding to the effective actual speed value are located using a binary search method. Based on the optimal proportional control parameter and optimal integral control parameter corresponding to the two adjacent discrete constant speed points, the target proportional control parameter and target integral control parameter are calculated using a linear interpolation method. This can include: Step 1: Initializing the starting index of the discrete constant speed point array to 0 and the ending index to the array length minus 1, and calculating the midpoint of the index, mid; Step 2: Comparing the effective actual speed value with the discrete constant speed point corresponding to the midpoint of the index, if the effective actual speed value... If the actual speed value is less than the discrete constant speed point corresponding to the index mid, then update the end index to mid-1; if the effective actual speed value is greater than the discrete constant speed point corresponding to the index mid, then update the initial index to mid+1. Step 3: Repeat step 2 until the starting index is greater than the ending index, and take the discrete constant speed points corresponding to the current ending index and the starting index as the two adjacent discrete constant speed points corresponding to the effective actual speed value. Step 4: Based on the optimal proportional control parameter and optimal integral control parameter corresponding to the two adjacent discrete constant speed points, calculate the target proportional control parameter and target integral control parameter using linear interpolation. The calculation formula for linear interpolation is: Where X is the effective actual speed value, X1 and X2 are two adjacent discrete constant speed points obtained by positioning, Y1 is the optimal proportional control parameter or optimal integral control parameter corresponding to X1, Y2 is the optimal proportional control parameter or optimal integral control parameter corresponding to X2, and Y is the target proportional control parameter or target integral control parameter corresponding to the effective actual speed value.

[0065] You can refer to this. Figure 3 , Figure 3This is a flowchart example of an interval query method provided by an embodiment of the present invention. Here, min refers to the minimum index of the current search interval, and mid refers to the index median. First, calculate the index median mid of the pre-stored discrete rotational speed array (for example, if the mapping table array stores 1000, 2000, 3000 RPM, the mid of indices 0 / 1 / 2 is 1), and use this as the initial positioning point for binary search to improve the table lookup efficiency. Exact match judgment: Compare the current effective actual rotational speed with the discrete rotational speed corresponding to mid. If the two are exactly the same (for example, the effective actual rotational speed is 2000 RPM), directly retrieve the PI parameters at this point. If they are not the same (for example, the effective actual rotational speed is 1500 RPM), then enter the subsequent interval positioning step. Determine whether the search interval has been reduced to the minimum (for example, when index min = 0, mid = 0). If it has not been reduced to the minimum, adjust the search interval (for example, when the effective actual rotational speed < the rotational speed corresponding to mid, reduce the right boundary). If it has been reduced to the minimum, calculate the interval median of adjacent discrete rotational speeds (for example, the interval median of 1000 RPM and 2000 RPM is 1500 RPM). Interpolation calculation and result output: If the interval median still does not exactly match the effective actual rotational speed, continue to adjust the search interval until the adjacent discrete rotational speed points are finally locked. Subsequently, perform linear interpolation through the formula to obtain the PI parameters corresponding to the current effective actual rotational speed. After recording the results, the process ends. This process quickly reduces the search range through binary search and combines linear interpolation to bridge the gaps between discrete rotational speed points, which not only ensures the query efficiency of PI parameters (meeting the requirements of frequent rotational speed switching of sewing machines), but also realizes continuous and smooth switching of parameters, avoids sudden changes in rotational speed control, and ensures the operating stability under different sewing conditions.

[0066] Furthermore, after pre-establishing the mapping table of different rotational speeds and optimal control parameters, the following steps can also be included: During system operation, continuously monitor the rotational speed fluctuation value of the servo motor. When the rotational speed fluctuation value exceeds the preset fluctuation threshold for a preset number of consecutive times, trigger the parameter re-calibration process, and supplement the optimally re-calibrated control parameters to the mapping table. In this embodiment, continuously monitoring the rotational speed fluctuation and using the condition of exceeding the threshold for a preset number of consecutive times as the trigger can not only timely capture the problem of decreased adaptability of the original PI parameters caused by long-term operation of the equipment, load changes, etc., but also avoid false triggering caused by single accidental fluctuations, ensuring the stability of system operation. Triggering the parameter re-calibration and supplementing the new parameters to the mapping table can dynamically optimize the parameter adaptability of the mapping table, make the rotational speed loop control parameters continuously match the optimal state according to the actual working conditions, so as to maintain the stability and control accuracy of the servo motor speed in the long term, ensure that the industrial sewing machine always maintains uniform stitch and smooth operation during long-term and diverse sewing operations, and improve the durability of the equipment and the consistency of operation quality.

[0067] S104: Through the speed loop controller, based on the target proportional control parameters and the target integral control parameters, the deviation between the target speed and the effective actual speed value is adjusted proportionally and integrally, and the control quantity is output to drive the servo motor.

[0068] In this embodiment, the speed loop controller refers to a speed loop PI controller. As the core unit for servo motor speed regulation, the speed loop controller first retrieves the target proportional control parameter (Kp) and target integral control parameter (Ki) obtained through lookup table or interpolation calculation. Then, it calculates the deviation between the target speed set for the industrial sewing machine and the effective actual speed after filtering and absolute value processing. Subsequently, it performs proportional and integral calculations on this deviation value according to the PI control algorithm and superimposes the results to finally generate the corresponding control quantity. This control quantity is transmitted to the servo motor drive unit, which changes the motor's output torque by adjusting the motor's input current or voltage, thereby driving the servo motor's actual speed to quickly and stably approach and track the target speed, thus meeting the requirements of speed accuracy and dynamic response of the industrial sewing machine under different sewing conditions. It should be noted that the servo motor is the power actuator of the industrial sewing machine, responsible for outputting torque to drive the sewing machine head; the speed loop is the core component of the speed closed-loop regulation in the servo control system. The performance of the speed loop directly determines the smoothness and accuracy of the servo motor during frequent starts and stops, acceleration and deceleration, and wide speed operation. It is the core to ensure uniform stitches and stable operation under different sewing conditions.

[0069] The industrial sewing machine speed loop control method provided in this embodiment of the invention proceeds as follows: S101: A mapping table between different speeds and optimal control parameters is pre-established; the optimal control parameters include optimal proportional control parameters and optimal integral control parameters; S102: The actual speed of the industrial sewing machine servo motor is obtained through a photoelectric encoder, the actual speed is filtered and its absolute value is taken to obtain the effective actual speed; S103: The mapping table is queried using the effective actual speed as an index to obtain the target proportional control parameters and the target integral control parameters; S104: The speed loop controller adjusts the deviation between the target speed and the effective actual speed value proportionally and integrally based on the target proportional control parameters and the target integral control parameters, and outputs a control quantity to drive the servo motor. Addressing the transient demands of industrial sewing machines operating across a wide speed range and undergoing frequent starts, stops, accelerations, and decelerations, as well as the differentiated control requirements of various working conditions such as high-speed straight-line sewing, complex pattern sewing, and sewing of thick or elastic fabrics, this method pre-establishes a mapping table between speed and optimal PI control parameters. By combining photoelectric encoder speed detection, absolute value filtering, and table lookup interpolation for parameter matching, it overcomes the shortcomings of traditional fixed-parameter PI controllers that rely on a single parameter to adapt to all working conditions. This ensures the system maintains optimal control across the entire speed range, effectively improving the control accuracy and smoothness of motor speed under different sewing tasks and guaranteeing stitch uniformity. Furthermore, compared to complex adaptive algorithms such as model reference adaptation and fuzzy control, this method employs lightweight control logic using offline calibration and online table lookup interpolation. It eliminates the need for real-time complex parameter optimization calculations, significantly reducing the computational load on the servo motor controller. This achieves a leap in control performance without increasing hardware costs, avoiding the difficulties and high costs associated with complex algorithm implementation. This aligns perfectly with the high cost-effectiveness and rapid response of industrial sewing machines, demonstrating significant value for industrialization and promotion.

[0070] For a clearer understanding of this invention, please refer to the following details. Figure 4 , Figure 4 A flowchart illustrating an industrial sewing machine speed loop control method provided in this embodiment of the invention may specifically include:

[0071] When the industrial sewing machine system is working, the user selects the sewing mode, such as "high-speed straight sewing," through the human-machine interface. The speed setting module generates the corresponding target speed curve. The speed feedback module obtains the actual motor speed in real time through a photoelectric encoder, and the motor controller executes the following process:

[0072] 1. Read the current actual speed value MotorSpeedFilter and take its absolute value MotorSpeedFilterAbs;

[0073] 2. Using MotorSpeedFilterAbs as the index, query the pre-stored speed loop PI parameter mapping model (i.e., the mapping table). Assume that the mapping table has calibration values ​​(Kp1, Ki1) and (Kp2, Ki2) at speeds of 1000 RPM and 2000 RPM, respectively.

[0074] 3. If MotorSpeedFilterAbs is 1500 RPM, the target parameters for the current output are calculated using linear interpolation via the PI parameter interpolation module.

[0075] The calculation of Kicurrent is similar;

[0076] 4. The speed loop PI controller uses the calculated Kpcurrent and Kicurrent parameters to adjust the speed deviation and outputs the adjustment amount to drive the motor.

[0077] Through the above method, when an industrial sewing machine switches from low-speed fabric feeding to high-speed sewing, or when the needle suddenly pierces thick material, the control system can automatically and smoothly adjust to the controller PI parameters most suitable for the current speed and load state, thereby always maintaining optimal dynamic performance and control accuracy. This method also has the following advantages:

[0078] (1) Full-speed-range performance optimization: Through the PI parameter mapping model of the speed loop, the PI controller parameters can be dynamically adjusted according to the real-time speed of the sewing machine. In view of the characteristics of high-speed sewing requiring fast response and low-speed sewing requiring high torque stability, the optimal parameter group is called respectively to ensure excellent dynamic response and control accuracy in the entire range from low speed to high speed, effectively improving the sewing quality.

[0079] (2) Improved robustness to nonlinear factors: The system can effectively compensate for nonlinear factors in the sewing process, such as sudden load changes caused by changes in fabric thickness, needle puncture resistance, friction and clearance in the transmission system, etc. When load changes cause speed fluctuations, this method can quickly switch to the appropriate parameter set, quickly adjust the speed fluctuations, and ensure uniform and beautiful stitches.

[0080] (3) Simplified control design and easy to implement in engineering: Compared with complex adaptive algorithms, this method has a simple structure, low computational load, and low requirements for microprocessors, which greatly reduces the development cost and complexity of the system and is very suitable for industrial sewing machine products for mass production.

[0081] (4) Achieve self-adaptation: By associating different sewing modes, such as "thick material mode", "high-speed flat sewing mode" and "fancy sewing mode" with different parameter mapping tables, the system can adapt to different sewing process requirements, thereby improving the product's intelligence level and market competitiveness.

[0082] Testing showed that, after adopting the control system of this invention, the motor speed control accuracy was significantly improved in "straight seam mode," as shown in Table 1, proving that the method is practical and effective. .

[0083] Table 1 Control Accuracy Comparison Table

[0084]

[0085] The following describes the industrial sewing machine speed loop control device provided in the embodiments of the present invention. The industrial sewing machine speed loop control device described below can be referred to in correspondence with the industrial sewing machine speed loop control method described above.

[0086] Please refer to the details. Figure 5 , Figure 5 A schematic diagram of a speed ring control device for an industrial sewing machine provided in an embodiment of the present invention may include:

[0087] The mapping table construction module 100 is used to pre-establish mapping tables between different speeds and optimal control parameters; the optimal control parameters include optimal proportional control parameters and optimal integral control parameters.

[0088] The speed processing module 200 is used to obtain the actual speed of the industrial sewing machine servo motor through a photoelectric encoder, filter the actual speed and take the absolute value to obtain the effective actual speed.

[0089] The query module 300 is used to query the mapping table using the effective actual speed as an index to obtain the target proportional control parameters and the target integral control parameters.

[0090] The control module 400 is used to adjust the deviation between the target speed and the effective actual speed value by means of the speed loop controller, based on the target proportional control parameters and the target integral control parameters, and output a control quantity to drive the servo motor.

[0091] Furthermore, based on the above embodiments, the mapping table construction module 100 may include:

[0092] The simulation unit is used to simulate the actual load using a dynamometer and control the servo motor to maintain stable operation at multiple discrete constant speed points under different load conditions.

[0093] The filtering unit is used to filter out the optimal proportional control parameter and the optimal integral control parameter with the fastest system response and the overshoot less than a preset threshold for each discrete constant speed point using the operating condition tuning method.

[0094] A recording unit is used to record each discrete constant speed point and the corresponding optimal proportional control parameter and optimal integral control parameter into the mapping table.

[0095] Furthermore, based on the above embodiments, the discrete constant speed point is the speed value corresponding to the straight seam, pattern seam, and thick material seam of the industrial sewing machine.

[0096] Furthermore, based on any of the above embodiments, the query module 300 may include:

[0097] The matching unit is used to take the optimal proportional control parameter and the optimal integral control parameter corresponding to the discrete constant speed point as the target proportional control parameter and the target integral control parameter if the effective actual speed value completely matches any discrete constant speed point in the mapping table.

[0098] An interval unit is used to locate two adjacent discrete constant speed points corresponding to the effective actual speed value by means of a binary search method if the effective actual speed value is within the range of discrete constant speed points in the mapping table. Based on the optimal proportional control parameter and the optimal integral control parameter corresponding to the two adjacent discrete constant speed points, the target proportional control parameter and the target integral control parameter are calculated by linear interpolation.

[0099] Furthermore, based on any of the above embodiments, the industrial sewing machine speed ring control device may further include:

[0100] The first determining module is used to, if the effective actual speed value is less than the minimum value of the discrete constant speed points in the mapping table, take the optimal proportional control parameter and the optimal integral control parameter corresponding to the minimum value as the target proportional control parameter and the target integral control parameter, respectively.

[0101] The second determining module is used to, if the effective actual speed value is greater than the maximum value of the discrete constant speed points in the mapping table, use the optimal proportional control parameter and the optimal integral control parameter corresponding to the maximum value as the target proportional control parameter and the target integral control parameter, respectively.

[0102] Furthermore, based on any of the above embodiments, the interval unit may include:

[0103] The first execution subunit is used to execute step 1: initialize the starting index of the discrete constant speed point array to 0 and the ending index to the array length minus 1, and calculate the midpoint value of the index;

[0104] The second execution subunit is used to execute step 2: compare the effective actual speed value with the discrete constant speed point corresponding to the index value mid; if the effective actual speed value is less than the discrete constant speed point corresponding to the index value mid, then update the end index to mid-1; if the effective actual speed value is greater than the discrete constant speed point corresponding to the index value mid, then update the initial index to mid+1.

[0105] The third execution subunit is used to execute step 3: repeat step 2 until the starting index is greater than the ending index, and take the discrete constant speed points corresponding to the current ending index and the starting index as the two adjacent discrete constant speed points corresponding to the effective actual speed value;

[0106] The fourth execution subunit is used to execute step 4: based on the optimal proportional control parameters and optimal integral control parameters corresponding to the two adjacent discrete constant speed points, the target proportional control parameters and the target integral control parameters are calculated using linear interpolation; the calculation formula for the linear interpolation method is: ;

[0107] Where X is the effective actual speed value, X1 and X2 are two adjacent discrete constant speed points obtained by positioning, Y1 is the optimal proportional control parameter or optimal integral control parameter corresponding to X1, Y2 is the optimal proportional control parameter or optimal integral control parameter corresponding to X2, and Y is the target proportional control parameter or target integral control parameter corresponding to the effective actual speed value.

[0108] Based on the above embodiments, the industrial sewing machine speed ring control device may further include:

[0109] The retuning module is used to monitor the speed fluctuation value of the servo motor in real time during system operation after a mapping table of different speeds and optimal control parameters is established in advance. When the speed fluctuation value exceeds a preset fluctuation threshold for a preset number of consecutive preset times, the parameter retuning process is triggered to supplement the optimal control parameters obtained by retuning into the mapping table.

[0110] It should be noted that the order of the modules and units in the above-mentioned industrial sewing machine speed ring control device can be changed without affecting the logic.

[0111] The industrial sewing machine speed loop control device provided in this embodiment of the invention includes a mapping table construction module 100 for pre-establishing a mapping table between different speeds and optimal control parameters; the optimal control parameters include optimal proportional control parameters and optimal integral control parameters; a speed processing module 200 for obtaining the actual speed of the industrial sewing machine servo motor through a photoelectric encoder, filtering the actual speed and taking its absolute value to obtain the effective actual speed; a query module 300 for querying the mapping table using the effective actual speed as an index to obtain the target proportional control parameters and target integral control parameters; and a control module 400 for using a speed loop controller to perform proportional-integral adjustment on the deviation between the target speed and the effective actual speed value based on the target proportional control parameters and the target integral control parameters, and outputting a control quantity to drive the servo motor. Addressing the transient demands of industrial sewing machines operating across a wide speed range and undergoing frequent starts, stops, accelerations, and decelerations, as well as the differentiated control requirements of various working conditions such as high-speed straight-line sewing, complex pattern sewing, and sewing of thick or elastic fabrics, this method pre-establishes a mapping table between speed and optimal PI control parameters. By combining photoelectric encoder speed detection, absolute value filtering, and table lookup interpolation for parameter matching, it overcomes the shortcomings of traditional fixed-parameter PI controllers that rely on a single parameter to adapt to all working conditions. This ensures the system maintains optimal control across the entire speed range, effectively improving the control accuracy and smoothness of motor speed under different sewing tasks and guaranteeing stitch uniformity. Furthermore, compared to complex adaptive algorithms such as model reference adaptation and fuzzy control, this method employs lightweight control logic using offline calibration and online table lookup interpolation. It eliminates the need for real-time complex parameter optimization calculations, significantly reducing the computational load on the servo motor controller. This achieves a leap in control performance without increasing hardware costs, avoiding the difficulties and high costs associated with complex algorithm implementation. This aligns perfectly with the high cost-effectiveness and rapid response of industrial sewing machines, demonstrating significant value for industrialization and promotion.

[0112] The following describes the industrial sewing machine speed loop control device provided in the embodiments of the present invention. The industrial sewing machine speed loop control device described below can be referred to in correspondence with the industrial sewing machine speed loop control method described above.

[0113] Please refer to Figure 6 , Figure 6 A schematic diagram of a speed loop control device for an industrial sewing machine provided in an embodiment of the present invention may include:

[0114] Memory 10 is used to store computer programs;

[0115] The processor 20 is used to execute a computer program to implement the above-described industrial sewing machine speed loop control method.

[0116] The memory 10, processor 20, and communication interface 31 all communicate with each other through the communication bus 32.

[0117] In this embodiment of the invention, the memory 10 is used to store one or more programs. The programs may include program code, which includes computer operation instructions. In this embodiment of the invention, the memory 10 may store programs for implementing the following functions:

[0118] A mapping table between different speeds and optimal control parameters is pre-established; the optimal control parameters include the optimal proportional control parameters and the optimal integral control parameters.

[0119] The actual speed of the servo motor of the industrial sewing machine is obtained by photoelectric encoder, the actual speed is filtered and the absolute value is taken to obtain the effective actual speed.

[0120] The target proportional control parameters and target integral control parameters are obtained by querying the mapping table using the effective actual speed as the index.

[0121] The speed loop controller adjusts the deviation between the target speed and the effective actual speed value using proportional and integral control parameters, based on the target proportional control parameters and the target integral control parameters, and outputs a control quantity to drive the servo motor.

[0122] In one possible implementation, the memory 10 may include a program storage area and a data storage area, wherein the program storage area may store the operating system and applications required for at least one function; and the data storage area may store data created during use.

[0123] Furthermore, memory 10 may include read-only memory and random access memory, providing instructions and data to the processor. A portion of the memory may also include NVRAM. The memory stores operating systems and operating instructions, executable modules, or data structures, or subsets thereof, or extended sets thereof, wherein the operating instructions may include various operating instructions for implementing various operations. The operating system may include various system programs for implementing various basic tasks and handling hardware-based tasks.

[0124] Processor 20 can be a central processing unit (CPU), an application-specific integrated circuit, a digital signal processor, a field-programmable gate array, or other programmable logic device. Processor 20 can be a microprocessor or any conventional processor. Processor 20 can call programs stored in memory 10.

[0125] Communication interface 31 can be an interface for the communication module, used to connect with other devices or systems.

[0126] Of course, it should be noted that, Figure 6 The structure shown does not constitute a limitation on the industrial sewing machine speed loop control device in the embodiments of the present invention. In practical applications, the industrial sewing machine speed loop control device may include more than Figure 6 More or fewer components as shown, or combinations of certain components.

[0127] The readable storage medium provided in the embodiments of the present invention is described below. The readable storage medium described below can be referred to in correspondence with the industrial sewing machine speed loop control method described above.

[0128] The present invention also provides a readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the above-described industrial sewing machine speed loop control method.

[0129] The computer-readable storage medium may include various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0130] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to in the method section.

[0131] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0132] Finally, it should be noted that in this document, relationships such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0133] The present invention provides a detailed description of an industrial sewing machine speed loop control method, apparatus, device, and computer-readable storage medium. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for controlling the rotational speed loop of an industrial sewing machine, characterized in that, include: A mapping table between different speeds and optimal control parameters is pre-established; the optimal control parameters include optimal proportional control parameters and optimal integral control parameters. The actual speed of the servo motor of the industrial sewing machine is obtained by a photoelectric encoder. The actual speed is then filtered and its absolute value is taken to obtain the effective actual speed. The target proportional control parameters and target integral control parameters are obtained by querying the mapping table using the effective actual speed as the index. The speed loop controller adjusts the deviation between the target speed and the effective actual speed value using proportional-integral adjustment based on the target proportional control parameters and the target integral control parameters, and outputs a control quantity to drive the servo motor.

2. The industrial sewing machine speed loop control method according to claim 1, characterized in that, A mapping table between different speeds and optimal control parameters is pre-established, including: Using a dynamometer to simulate the actual load, the servo motor is controlled to maintain stable operation at multiple discrete constant speed points under different load conditions; For each discrete constant speed point, the optimal proportional control parameter and the optimal integral control parameter with the fastest system response and the overshoot less than a preset threshold are selected by the operating condition tuning method. Each discrete constant speed point and its corresponding optimal proportional control parameter and optimal integral control parameter are recorded in the mapping table.

3. The industrial sewing machine speed loop control method according to claim 2, characterized in that, The discrete constant speed points are the speed values ​​corresponding to straight seams, pattern seams, and thick material seams on industrial sewing machines.

4. The industrial sewing machine speed loop control method according to any one of claims 1 to 3, characterized in that, Using the effective actual speed as an index, the mapping table is queried to obtain the target proportional control parameters and target integral control parameters, including: If the effective actual speed value completely matches any discrete constant speed point in the mapping table, then the optimal proportional control parameter and the optimal integral control parameter corresponding to the discrete constant speed point are used as the target proportional control parameter and the target integral control parameter. If the effective actual speed value is within the range of discrete constant speed points in the mapping table, then the two adjacent discrete constant speed points corresponding to the effective actual speed value are located by binary search. Based on the optimal proportional control parameter and the optimal integral control parameter corresponding to the two adjacent discrete constant speed points, the target proportional control parameter and the target integral control parameter are calculated by linear interpolation.

5. The industrial sewing machine speed loop control method according to claim 4, characterized in that, Also includes: If the effective actual speed value is less than the minimum value of the discrete constant speed points in the mapping table, then the optimal proportional control parameter and the optimal integral control parameter corresponding to the minimum value are respectively used as the target proportional control parameter and the target integral control parameter; If the effective actual speed value is greater than the maximum value of the discrete constant speed points in the mapping table, then the optimal proportional control parameter and the optimal integral control parameter corresponding to the maximum value are respectively used as the target proportional control parameter and the target integral control parameter.

6. The industrial sewing machine speed loop control method according to claim 4, characterized in that, If the effective actual speed value falls within the range of discrete constant speed points in the mapping table, then two adjacent discrete constant speed points corresponding to the effective actual speed value are located using a binary search method. Based on the optimal proportional control parameter and optimal integral control parameter corresponding to the two adjacent discrete constant speed points, the target proportional control parameter and the target integral control parameter are calculated using a linear interpolation method, including: Step 1: Initialize the discrete constant speed point array with the starting index 0 and the ending index 1 minus the array length, and calculate the midpoint of the index; Step 2: Compare the effective actual speed value with the discrete constant speed point corresponding to the index value mid. If the effective actual speed value is less than the discrete constant speed point corresponding to the index value mid, then update the end index to mid-1. If the effective actual speed value is greater than the discrete constant speed point corresponding to the index value mid, then update the initial index to mid+1. Step 3: Repeat step 2 until the starting index is greater than the ending index, and take the discrete constant speed points corresponding to the current ending index and the starting index as the two adjacent discrete constant speed points corresponding to the effective actual speed value; Step 4: Based on the optimal proportional control parameters and optimal integral control parameters corresponding to the two adjacent discrete constant speed points, calculate the target proportional control parameters and the target integral control parameters using linear interpolation; the calculation formula for the linear interpolation method is: ; Where X is the effective actual speed value, X1 and X2 are two adjacent discrete constant speed points obtained by positioning, Y1 is the optimal proportional control parameter or optimal integral control parameter corresponding to X1, Y2 is the optimal proportional control parameter or optimal integral control parameter corresponding to X2, and Y is the target proportional control parameter or target integral control parameter corresponding to the effective actual speed value.

7. The industrial sewing machine speed loop control method according to claim 1, characterized in that, After establishing a mapping table between different speeds and optimal control parameters in advance, the following is also included: During system operation, the speed fluctuation value of the servo motor is monitored in real time. When the speed fluctuation value exceeds the preset fluctuation threshold for a preset number of consecutive preset times, the parameter retuning process is triggered, and the optimal control parameters obtained by retuning are added to the mapping table.

8. A speed control device for an industrial sewing machine, characterized in that, include: The mapping table construction module is used to pre-build mapping tables between different speeds and optimal control parameters; the optimal control parameters include optimal proportional control parameters and optimal integral control parameters. The speed processing module is used to obtain the actual speed of the industrial sewing machine servo motor through a photoelectric encoder, filter the actual speed and take the absolute value to obtain the effective actual speed. The query module is used to query the mapping table using the effective actual speed as an index to obtain the target proportional control parameters and the target integral control parameters; The control module is used to adjust the deviation between the target speed and the effective actual speed value using a speed loop controller based on the target proportional control parameters and the target integral control parameters, and output a control quantity to drive the servo motor.

9. A speed control device for an industrial sewing machine, characterized in that, include: Memory, used to store computer programs; A processor, configured to implement the industrial sewing machine speed loop control method as described in any one of claims 1 to 7 when executing the computer program.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions, which, when loaded and executed by a processor, implement the industrial sewing machine speed loop control method as described in any one of claims 1 to 7.

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