Load-adaptive household embroidery machine main shaft speed regulation method and speed regulation device thereof

Abstract

The invention discloses a load-adaptive household embroidery machine main shaft speed regulation method and device, and the method comprises the following steps: constructing a corresponding relation table between the rotating speed of a main shaft and a PWM control signal, and taking the corresponding relation table as a target speed regulation basis; dynamically setting a target main shaft rotating speed corresponding to each needle based on the needle pitch length and the embroidery process position of the needle in the embroidery path; the spindle rotating speed is obtained in real time through a photoelectric coded disc, and the pulse frequency is calculated in each period to obtain the actual rotating speed; if the sudden load disturbance does not exist at present, PID speed regulation based on the error between the set rotating speed and the current rotating speed is executed; if it is monitored that the actual rotating speed suddenly drops and is lower than 280 revolutions per minute, and the deviation between the actual rotating speed and a set value exceeds 100 revolutions per minute, it is judged that the rotating speed is in a locked-rotor state, PWM output is limited not to exceed a preset locked-rotor PWM upper limit, and the value is a PWM value corresponding to the rotating speed of 300 revolutions per minute; by constructing a speed regulation feedback closed loop, quick response and stable control of main shaft load sudden change in a multi-layer high-density embroidery scene are realized.

Description

Technical Field

[0001] The present invention relates to the technical field of embroidery machine control systems, and in particular to a load-adaptive main shaft speed regulation method and a speed regulation device for a household embroidery machine. Background Art

[0002] Existing home embroidery machines mostly use fixed speed ratios or simple mechanical drives. Their spindle speed control typically relies on a brushed or brushless DC motor, using a PID algorithm combined with a PWM control signal to adjust the speed. Specifically, the controller adjusts the voltage via PWM output based on the deviation between the spindle's real-time speed feedback and the set target speed, driving the motor and achieving spindle speed regulation during the embroidery process.

[0003] However, in actual embroidery, especially when embroidering two to four layers of overlapping stitches with a stitch density of less than 2mm, the spindle is prone to sudden load changes as it penetrates the fabric. This rapid load change can cause the spindle speed to drop sharply and the motor current to increase dramatically, even exceeding the system's overcurrent protection threshold and triggering an automatic system restart, seriously affecting embroidery quality and work efficiency.

[0004] In addition, since the existing control system lacks effective dynamic limiting and overshoot suppression mechanisms, if a sudden load change occurs during the embroidery process, the control system often attempts to maintain the target speed by unidirectionally increasing the PWM output. However, this can easily cause the motor output torque to be excessive, thereby causing severe vibration and mechanical impact noise, posing a threat to the equipment structure and stability.

[0005] Therefore, the existing spindle speed control method of household embroidery machines still has significant deficiencies in load adaptability, vibration suppression and abnormal recovery. There is an urgent need for a speed control method that can achieve adaptive response to load mutations and ensure stable operation of the system without replacing hardware or circuit structure. Summary of the Invention

[0006] In response to the above problems, the present invention provides a load-adaptive spindle speed control method and device for a household embroidery machine, so as to solve the problems in the prior art such as overcurrent protection, system restart and sharp increase in noise of the spindle under sudden changes in embroidery load.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A load-adaptive spindle speed regulation method for a household embroidery machine comprises the following steps:

[0009] Construct a corresponding relationship table between the spindle speed and the PWM control signal as the basis for target speed regulation;

[0010] Dynamically set the target spindle speed for each stitch based on the stitch length and embroidery position of each stitch in the embroidery path;

[0011] The spindle speed is acquired in real time through the photoelectric encoder disk, and the pulse frequency is calculated in each cycle to obtain the actual speed;

[0012] If there is no sudden load disturbance, the PID speed regulation based on the error between the set speed and the current speed is executed;

[0013] If the actual speed drops sharply and is lower than 280 rpm, and the deviation from the set value exceeds 100 rpm, it is judged to be a stalled state, and the PWM output is limited to not exceed the preset "stall PWM upper limit", which is the PWM value corresponding to a speed of 300 rpm;

[0014] When the spindle accelerates and recovers, and the actual speed approaches the target set value, that is, the speed error is in the range of (-100, 0), speed overshoot control is executed to limit the PWM output to no more than the PWM value corresponding to the set speed plus 20;

[0015] The above strategy is used to construct a speed control feedback closed loop, which can achieve rapid response and stable control of sudden changes in the spindle load in multi-layer and high-density embroidery scenarios.

[0016] Furthermore, the PWM mapping table records a PWM value every 100 revolutions per minute, covering a common operating range of 100 to 700 revolutions per minute.

[0017] Furthermore, the "locked-rotor PWM upper limit" is a PWM value corresponding to a rotation speed of 300 rpm, which is obtained by looking up a table in the system.

[0018] Furthermore, the “PWM output does not exceed the set value corresponding to PWM plus 20” means that after the system looks up the table to obtain the PWM value corresponding to the target speed, it adds 20 to the upper limit of the limit.

[0019] Furthermore, the spindle control cycle is 10 milliseconds, and speed detection, error calculation, speed control, stall judgment and limit judgment are executed in sequence in each cycle.

[0020] A household embroidery machine spindle speed regulating device for implementing the method described in claim 1, comprising:

[0021] A mapping construction unit, used to establish a lookup table mapping relationship between the spindle speed and PWM;

[0022] The pattern analysis module is used to dynamically set the target spindle speed according to the embroidery data;

[0023] The spindle speed detection module uses a photoelectric encoder and pulse counting logic to achieve periodic detection of the spindle speed;

[0024] PID speed control unit, used to calculate speed error and output PWM control signal;

[0025] State discrimination module, used to identify stall or overshoot risks and limit PWM output;

[0026] PWM output module, used to output the limited PWM value to the spindle motor driver

[0027] Furthermore, the state judgment module is provided with a dual judgment logic: when the actual speed is less than 280 rpm and the error is less than -100, it is identified as a stall; when the error is between (-100, 0), it is identified as an overshoot risk.

[0028] Furthermore, the PWM output module has a limiting function. When the limiting control is triggered, the PWM signal does not exceed the PWM value corresponding to the set target speed plus 20.

[0029] Furthermore, the device is embedded in an ARM core microcontroller and runs timed interrupt tasks for real-time control and data acquisition, with a minimum control granularity of 20 microseconds.

[0030] The method of the present invention establishes a correspondence table between spindle speed and PWM control signals, setting the target speed for each stitch based on the pattern path before embroidery. The system detects the actual spindle speed every cycle and implements a PID speed control strategy based on the error between the set value and the current value.

[0031] If the actual speed drops sharply below 280 rpm, with an error greater than 100 rpm, the system determines that the motor is in a stalled state and limits the PWM output to a "stall PWM upper limit," which is the PWM value corresponding to a speed of 300 rpm. This effectively prevents abnormal current increases from triggering overcurrent protection.

[0032] When the stall state is released, the spindle resumes acceleration, and the actual speed approaches the target value (the error is between -100 and 0 rpm), the system automatically enters the speed overshoot control stage, limiting the PWM output to no more than the PWM value corresponding to the set target speed plus 20, to avoid impact and noise caused by overshoot.

[0033] Compared to existing technologies, this invention achieves stable spindle speed control under varying load conditions, eliminating the need to modify motor type, mechanical structure, or power supply protection thresholds. Using only a speed regulation algorithm and state-discrimination logic, this method achieves stable spindle speed control under varying load conditions. This method boasts a simple structure, fast response, low implementation cost, and strong versatility, making it particularly suitable for upgrading and optimizing mid-range and low-end household embroidery machines.

[0034] The load-adaptive household embroidery machine spindle speed regulation method and device proposed in this invention, based on real-time monitoring of the actual spindle speed, combined with load disturbance state identification and limit control strategy, achieves the following significant technical effects without changing the machine structure, motor type, or power protection parameters:

[0035] 1. Implement multi-stage speed regulation logic under closed-loop state recognition to improve the stability and robustness of the speed regulation strategy.

[0036] This invention differs from traditional single-PID control paths by employing a speed regulation method that dynamically switches control strategies based on load disturbances. This method clearly delineates normal PID control zones, stall protection zones, and overshoot suppression zones. Each control zone has distinct trigger boundaries and PWM limiting strategies, effectively preventing the instability of single-PID control under nonlinear load conditions and enhancing the system's anti-disturbance capabilities.

[0037] 2. Under load mutation conditions, the system power overshoot is suppressed by limiting the maximum PWM output, reducing the stress impact of the drive link.

[0038] When the spindle momentarily stalls, conventional systems continuously increase PWM output to restore speed. This often causes a surge in current and torque, which in turn causes transient stress on the motor, pulleys, linkages, and other transmission mechanisms. This new system instantly enters "stall-limit control mode," forcibly limiting the maximum PWM output to 300 rpm. This prevents the system from entering a critical energy consumption zone and effectively reduces the load on the motor drive train.

[0039] 3. Suppress speed overshoot during the speed regulation process to prevent structural impact when the spindle suddenly increases from the low speed zone to the target speed.

[0040] After a stall is released, the spindle is prone to speed overshoot during recovery due to inertia and excessive PWM push. This invention incorporates a dedicated "overshoot control module" that limits PWM output to a narrow window of "set PWM + 20" when the actual speed approaches the target set value. This allows the system to steadily transition to the target speed with reduced power, significantly reducing mechanical impact and secondary noise between the needle bar, presser foot, and embroidery frame.

[0041] 4. Maintain stable system operation in the state of multi-layer overlapping and high-density embroidery, significantly improving the continuity and uniformity of embroidery.

[0042] In complex patterns with 2 to 4 overlapping layers and a stitch length less than 2mm, conventional systems are prone to embroidery interruptions or thread tearing due to sudden changes in load on a single needle. This invention, through periodic speed mutation detection and switching between limiting strategies, gives the spindle greater dynamic load adaptability, preventing stitch skipping and stalling, ensuring continuous embroidery quality and improving stitch consistency.

[0043] 5. Avoid repeated restarts after the system enters overcurrent protection, effectively reduce invalid recovery processes, and improve resource utilization efficiency.

[0044] A spindle stall can easily cause the drive current to quickly exceed the switching power supply's overcurrent protection threshold, triggering an automatic system restart. This process not only interrupts the embroidery process but also generates additional energy loss and system thermal load. This invention proactively detects stall conditions and preemptively reduces PWM output, allowing the system to recover before the critical fault point, thus avoiding the resource waste and electrical fatigue caused by repeated restarts.

[0045] 6. Achieve complex control objectives by simplifying control strategies, reducing hardware dependence and system implementation thresholds.

[0046] The entire control logic of this invention can be implemented within an existing ARM-based microcontroller, relying solely on speed data fed back by a photoelectric encoder. It eliminates the need for additional hardware such as current sensors and torque detectors. The algorithm boasts a compact structure and high computational efficiency, making speed control decisions within the conventional 20μs interrupt control granularity. It is suitable for resource-constrained home embroidery machine platforms.

[0047] In summary, the present invention provides a spindle speed regulation solution with unchanged structure, algorithm-driven and enhanced performance. It exhibits good stability, efficiency and system protection capabilities in coping with actual complex embroidery environments, and has significant engineering application value and industrial promotion potential. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 This is a system structure diagram of the load-adaptive household embroidery machine spindle speed regulation method of the present invention;

[0049] Figure 2 This is the overall embroidery process logic diagram of the main shaft speed control process in the embroidery process of the present invention;

[0050] Figure 3 This is a flow chart of the spindle speed control strategy of the present invention. DETAILED DESCRIPTION

[0051] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0052] Example:

[0053] See also Figures 1 to 3 , the present invention provides a technical solution:

[0054] A load-adaptive spindle speed regulation method for a household embroidery machine comprises the following steps:

[0055] Construct a corresponding relationship table between the spindle speed and the PWM control signal as the basis for target speed regulation;

[0056] Dynamically set the target spindle speed for each stitch based on the stitch length and embroidery position of each stitch in the embroidery path;

[0057] The spindle speed is acquired in real time through the photoelectric encoder disk, and the pulse frequency is calculated in each cycle to obtain the actual speed;

[0058] If there is no sudden load disturbance, the PID speed regulation based on the error between the set speed and the current speed is executed;

[0059] If the actual speed drops sharply and is lower than 280 rpm, and the deviation from the set value exceeds 100 rpm, it is judged to be a stalled state, and the PWM output is limited to not exceed the preset "stall PWM upper limit", which is the PWM value corresponding to a speed of 300 rpm;

[0060] When the spindle accelerates and recovers, and the actual speed approaches the target set value, that is, the speed error is in the range of (-100, 0), speed overshoot control is executed to limit the PWM output to no more than the PWM value corresponding to the set speed plus 20;

[0061] The above strategy is used to construct a speed control feedback closed loop, which can achieve rapid response and stable control of sudden changes in the spindle load in multi-layer and high-density embroidery scenarios.

[0062] Furthermore, the PWM mapping table records a PWM value every 100 revolutions per minute, covering a common operating range of 100 to 700 revolutions per minute.

[0063] Furthermore, the "locked-rotor PWM upper limit" is a PWM value corresponding to a rotation speed of 300 rpm, which is obtained by looking up a table in the system.

[0064] Furthermore, the “PWM output does not exceed the set value corresponding to PWM plus 20” means that after the system looks up the table to obtain the PWM value corresponding to the target speed, it adds 20 to the upper limit of the limit.

[0065] Furthermore, the spindle control cycle is 10 milliseconds, and speed detection, error calculation, speed control, stall judgment and limit judgment are executed in sequence in each cycle.

[0066] A household embroidery machine spindle speed regulating device for implementing the method described in claim 1, comprising:

[0067] A mapping construction unit, used to establish a lookup table mapping relationship between the spindle speed and PWM;

[0068] The pattern analysis module is used to dynamically set the target spindle speed according to the embroidery data;

[0069] The spindle speed detection module uses a photoelectric encoder and pulse counting logic to achieve periodic detection of the spindle speed;

[0070] PID speed control unit, used to calculate speed error and output PWM control signal;

[0071] State discrimination module, used to identify stall or overshoot risks and limit PWM output;

[0072] PWM output module, used to output the limited PWM value to the spindle motor driver

[0073] Furthermore, the state judgment module is provided with a dual judgment logic: when the actual speed is less than 280 rpm and the error is less than -100, it is identified as a stall; when the error is between (-100, 0), it is identified as an overshoot risk.

[0074] Furthermore, the PWM output module has a limiting function. When the limiting control is triggered, the PWM signal does not exceed the PWM value corresponding to the set target speed plus 20.

[0075] Furthermore, the device is embedded in an ARM core microcontroller and runs timed interrupt tasks for real-time control and data acquisition, with a minimum control granularity of 20 microseconds.

[0076] The method of the present invention establishes a correspondence table between spindle speed and PWM control signals, setting the target speed for each stitch based on the pattern path before embroidery. The system detects the actual spindle speed every cycle and implements a PID speed control strategy based on the error between the set value and the current value.

[0077] If the actual speed drops sharply below 280 rpm, with an error greater than 100 rpm, the system determines that the motor is in a stalled state and limits the PWM output to a "stall PWM upper limit," which is the PWM value corresponding to a speed of 300 rpm. This effectively prevents abnormal current increases from triggering overcurrent protection.

[0078] When the stall state is released, the spindle resumes acceleration, and the actual speed approaches the target value (the error is between -100 and 0 rpm), the system automatically enters the speed overshoot control stage, limiting the PWM output to no more than the PWM value corresponding to the set target speed plus 20, to avoid impact and noise caused by overshoot.

[0079] The method of the present invention is implemented in a microcontroller platform based on an ARM core. The control program runs under a timed interrupt mechanism with a minimum interrupt period of 20 microseconds. Its core control process completes a speed regulation cycle every 10 milliseconds.

[0080] During the system initialization phase, a table `g_m_pwm[7]` is first created to represent the relationship between spindle speed and PWM control output. This table records the standard PWM values of the spindle from 100 rpm to 700 rpm, sampling a set of PWM reference values every 100 rpm. Continuous speed output can be achieved through linear interpolation of PWM values.

[0081] Before embroidery processing, the target speed `SetSpeed` required for each stitch is analyzed and planned based on the stitch length, starting point, and end point of each stitch in the embroidery pattern. This sequence is written to the data buffer of the main control chip for use in each control cycle.

[0082] The specific implementation process is as follows:

[0083] This method is implemented in a microcontroller based on ARM core.

[0084] First, create a table g_m_pwm[7] that corresponds to the spindle speed and PWM. The corresponding PWM values are recorded for spindle speeds from 100 to 700 rpm, with one PWM value recorded every 100 rpm. The PWM value corresponding to each speed can be calculated using a linear lookup table.

[0085] In the control main loop, according to the embroidery pattern data, needle coordinate length and start-end process, the spindle speed of each needle is planned, the processing data is generated and stored in the processing buffer.

[0086] Start a timer interrupt function with a 20us interrupt period. This function controls the embroidery motion processing, including capturing the spindle angle and controlling the X and Y axis movement based on the spindle angle. It also adjusts the spindle speed, performs I / O detection, and performs timing tasks.

[0087] Read the spindle set speed SetSpeed for the next stitch and initialize related speed control variables, such as the speed reaching mark m_ToDestSpeedIsOK=0, the spindle maximum PWM limit m_max_pwm=C_MAX_PWM_650, C_MAX_PWM_650 is the PWM value corresponding to 650 rpm, and the speed tolerance m_M_SpdErr=30.

[0088] The speed detection module is called every 10ms. The speed detection module reads the number of pulses returned by the photoelectric encoder disk and calculates the current spindle speed FactSpeed.

[0089] The spindle speed control module is called every 10ms. First, the speed difference, m_Error, is calculated as FactSpeed - SetSpeed. The set speed is determined by the condition ABS(m_Error) <= m_M_SpdErr. If so, the flag m_ToDestSpeedIsOK is set to 1, eliminating the need for acceleration or deceleration, and the current PWM value, c_pwm, is output. Otherwise, acceleration or deceleration is required, using incremental PID P control. The PWM value is c_pwm += kp * m_Error, where c_pwm is the current output PWM, kp is the proportional gain, and m_Error is the speed deviation. When outputting PWM, c_pwm must be limited to min(c_pwm, m_max_pwm), where m_max_pwm is the maximum PWM limit.

[0090] The speed mutation detection module is called every 10ms. When m_ToDestSpeedIsOK == 1, the speed deviation m_Error <= -100, and the actual speed FactSpeed < 280 rpm, it indicates that a load mutation has occurred.

[0091] The stall PWM maximum limit control module is called every 10ms. When m_ToDestSpeedIsOK == 1 and a speed mutation occurs, the maximum PWM is set to the stall maximum PWM, m_max_pwm = C_PWM_MAX_DUZHUAN, which corresponds to a PWM output of 300 rpm. This prevents excessive current and motor force.

[0092] The speed overshoot control module is called every 10ms. When m_ToDestSpeedIsOK==1, the speed starts to accelerate as the PWM increases. When the difference between the set speed and the actual speed is m_Error>-100&&m_Error<0, the PWM output value is limited to c_pwm=min(c_pwm,GetSpeedDuty(SetSpeed)+20). The GetSpeedDuty() function obtains the PWM control value corresponding to the current set speed by looking up the table g_m_pwm[7]

[0093] During embroidery processing, each module of the device executes the following core control process:

[0094] 1. Speed detection module

[0095] The spindle speed is detected by a photoelectric encoder mounted on the spindle. Each spindle rotation generates 80 pulses. The system uses a pulse capture module to read the number of pulses within a 10ms time window and calculate the current spindle speed, `FactSpeed`.

[0096] 2.PID speed control module

[0097] Calculate the error value between the target speed and the current speed `m_Error = FactSpeed - SetSpeed`. If the absolute value of the error is less than the set allowable range `m_M_SpdErr = 30`, it is considered that the spindle has reached the target speed, and set the status flag `m_ToDestSpeedIsOK = 1`. Otherwise, enter the incremental proportional regulation: c_pwm += kp * m_Error

[0098] Where `c_pwm` is the current PWM output value and `kp` is the proportional gain coefficient. To prevent the output from being too large, perform the maximum PWM limit:

[0099] c_pwm = min(c_pwm, m_max_pwm)

[0100] Where `m_max_pwm` is the maximum allowable value of PWM in this period, and the default value is `C_MAX_PWM_650`, that is, the PWM value corresponding to 650 revolutions per minute.

[0101] 3. Speed mutation detection module

[0102] When `m_ToDestSpeedIsOK == 1`, and `m_Error <= -100`, and FactSpeed < 280 revolutions per minute, it is judged that the spindle is jammed, and enter the jammed control process.

[0103] 4. Jammed PWM maximum limit control module

[0104] In the jammed state, set the PWM output upper limit `m_max_pwm` of the current period to `C_PWM_MAX_DUZHUAN`, that is, the PWM value corresponding to 300 revolutions per minute, so as to prevent the motor current from being too large and triggering the system overcurrent protection.

[0105] 5. Overshoot control module

[0106] When the spindle starts to accelerate and recover, and the error value is within the range of `-100 < m_Error < 0`, it means that the spindle is about to approach the set speed. At this time, enable the overshoot control logic and limit the maximum PWM output value to:

[0107] m_max_pwm = GetSpeedDuty(SetSpeed) + 20

[0108] Where `GetSpeedDuty(SetSpeed)` represents the PWM value look-up table function corresponding to the set speed, and limit it not to exceed this value plus 20 to avoid problems such as the needle bar hitting, noise or skipped stitches caused by overshoot during the speed regulation process.

[0109] The above steps are repeated every 10ms, forming a complete closed-loop spindle speed control process. The system senses the spindle speed status in real time throughout the embroidery process and adaptively adjusts the control strategy based on different load disturbances, ensuring smooth spindle operation even in complex, multi-layer embroidery conditions.

[0110] The load-adaptive household embroidery machine spindle speed regulation method and device provided by the present invention have the following advantages:

[0111] 1. Improved load adaptability: By real-time monitoring of spindle speed changes and dynamically adjusting the PWM control output, it can effectively identify and respond to sudden load changes during the embroidery process caused by changes in fabric thickness, multiple layers of overlap, and dense stitch lengths, thereby avoiding embroidery failures or system abnormalities caused by sudden speed drops.

[0112] 2. Prevent overcurrent protection from being triggered: After stall identification, the PWM output upper limit is automatically limited to the PWM value corresponding to a speed of 300 rpm. This can effectively suppress the rapid rise of current, avoid triggering overcurrent protection and power restart, and improve the continuity and reliability of equipment operation.

[0113] 3. Suppress speed overshoot during speed regulation: When the spindle resumes acceleration and approaches the target speed, the system automatically activates the overshoot limitation mechanism, limiting the PWM output to the set target PWM value plus 20. This prevents problems such as structural collision, body resonance, or embroidery shifting caused by control overshoot, thereby reducing noise and improving embroidery precision.

[0114] 4. No need to increase hardware costs: The present invention is based on the existing motor system and realizes adaptive speed control only by optimizing the speed control algorithm and state control logic. There is no need to replace the spindle motor, adjust the drive circuit or add a sensor module. It has good hardware compatibility and promotion adaptability.

[0115] 5. The control process is stable and the response is timely: The entire speed regulation process uses a 10ms control cycle and integrates multiple strategy logics such as PID regulation, state recognition and limit control to form a closed-loop control system. It can maintain the smoothness and rhythm consistency of the spindle operation under various complex working conditions.

[0116] 6. Easy to implement and expand: This method can run on a conventional ARM architecture microcontroller platform. The control logic is simple and easy to implement in software. It is applicable to a variety of household embroidery machine control systems and can also be adapted to different embroidery products and fabric types through parameter adjustment.

[0117] In summary, the present invention not only improves the noise, shutdown and other problems caused by load fluctuations during the embroidery process, but also improves the robustness and operating efficiency of the speed regulation system, and has high engineering application value and industrial promotion prospects.

[0118] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A load-adaptive spindle speed control method for a household embroidery machine, characterized by: The steps include: Construct a corresponding relationship table between the spindle speed and the PWM control signal as the basis for target speed regulation; Dynamically set the target spindle speed for each stitch based on the stitch length and embroidery position of each stitch in the embroidery path; The spindle speed is acquired in real time through the photoelectric encoder disk, and the pulse frequency is calculated in each cycle to obtain the actual speed; If there is no sudden load disturbance, the PID speed control based on the error between the set speed and the current speed is executed; If the actual speed drops sharply below 280 rpm and deviates from the set value by more than 100 rpm, it is considered a stalled state and the PWM output is limited to a preset "stall PWM upper limit", which is the PWM value corresponding to a speed of 300 rpm. When the spindle accelerates and recovers, and the actual speed approaches the target set value, that is, the speed error is in the range of (-100, 0), speed overshoot control is executed to limit the PWM output to no more than the PWM value corresponding to the set speed plus 20; The above strategy is used to construct a speed control feedback closed loop, which can achieve rapid response and stable control of sudden changes in the spindle load in multi-layer and high-density embroidery scenarios.

2. The load-adaptive spindle speed regulation method for a household embroidery machine according to claim 1, characterized in that: The PWM mapping relationship table records a PWM value every 100 revolutions per minute, covering a common operating range of 100 to 700 revolutions per minute.

3. The load-adaptive spindle speed regulation method for a household embroidery machine according to claim 1, characterized in that: The "locked-rotor PWM upper limit" is the PWM value corresponding to a speed of 300 rpm, which is obtained by looking up the system table.

4. The load-adaptive spindle speed regulation method for a household embroidery machine according to claim 1, characterized in that: The phrase "PWM output does not exceed the set value corresponding to PWM plus 20" means that after the system looks up the table to obtain the PWM value corresponding to the target speed, it adds 20 to the upper limit of the limit.

5. The load-adaptive spindle speed regulation method for a household embroidery machine according to claim 1, characterized in that: The spindle control cycle is 10 milliseconds, and each cycle executes speed detection, error calculation, speed control, stall judgment and limit judgment in sequence.

6. A spindle speed regulating device for a household embroidery machine for implementing the method of claim 1, characterized in that: include: A mapping construction unit, used to establish a lookup table mapping relationship between the spindle speed and PWM; The pattern analysis module is used to dynamically set the target spindle speed according to the embroidery data; The spindle speed detection module uses a photoelectric encoder and pulse counting logic to achieve periodic detection of the spindle speed; PID speed control unit, used to calculate speed error and output PWM control signal; State discrimination module, used to identify stall or overshoot risks and limit PWM output; The PWM output module is used to output the limited PWM value to the spindle motor driver.

7. The device according to claim 6, characterized in that: The state judgment module is equipped with a dual judgment logic: when the actual speed is less than 280 rpm and the error is less than -100, it is identified as a stall; when the error is between (-100, 0), it is identified as an overshoot risk.

8. The device according to claim 6, characterized in that: The PWM output module has a limiting function. When the limiting control is triggered, the PWM signal does not exceed the PWM value corresponding to the set target speed plus 20.

9. The device according to claim 6, characterized in that: The device is embedded in an ARM core microcontroller and runs timed interrupt tasks for real-time control and data acquisition, with a minimum control granularity of 20 microseconds.

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