A presser foot slow descent control method, system, electronic device and sewing machine

Abstract

The application provides a presser foot slow descent control method, system, electronic device and sewing machine. The method comprises: obtaining target data; the target data comprises a target position, a current position and a preset slow descent position of a presser foot; the preset slow descent position is a preset pause position of the presser foot; comparing the target position and the preset slow descent position to obtain a comparison result; if the comparison result indicates that slow descent is needed, lowering the presser foot from the current position to the target position according to a preset slow descent strategy; and if the comparison result indicates that slow descent is not needed, lowering the presser foot from the current position to the target position according to a closed-loop control algorithm. The presser foot lowering speed can be effectively reduced for an electromagnet presser foot lifting mechanism, and noise is reduced. Meanwhile, the application range is wide, and the application is suitable for different electromagnet presser foot lifting mechanisms, such as flat sewing and overlock sewing.

Description

Technical Field

[0001] This application belongs to the field of sewing machine technology, and relates to a presser foot slow-down control method, and particularly to a presser foot slow-down control method, system, electronic equipment and sewing machine. Background Technology

[0002] In sewing machines, to reduce the labor intensity of workers, electromagnets are typically used to control the raising and lowering of the presser foot. Currently, sewing machines use a combination of electromagnets and presser foot height sensors. The controller measures the presser foot height and, based on an optimized control algorithm, controls the current to the electromagnet, allowing the presser foot to hover at any height. However, when using models where the presser foot is raised by an electromagnet, the presser foot descends relying on the downward force of a spring, producing a loud thud each time it is released. Summary of the Invention

[0003] The purpose of this application is to provide a presser foot slow-descent control method, system, electronic device, and sewing machine to solve the problem of loud impact noise generated when the presser foot descends in existing sewing machines.

[0004] In a first aspect, this application provides a presser foot slow-descent control method applied to a sewing machine. The sewing machine includes a presser foot, an electromagnet assembly, and a sensor assembly. The electromagnet assembly includes a magnet, and the sensor assembly includes a magnetic detection sensor. The magnetic detection sensor is used to detect the linearly changing electrical signal of the magnet as the presser foot moves up and down, so that the sewing machine can determine the current position of the presser foot based on the electrical signal. The sewing machine also includes a detection device for generating a voltage signal based on user actions, so that the sewing machine can obtain the target position of the presser foot based on the voltage signal. The method includes: acquiring target data; the target data includes the target position, current position, and preset slow-descent position of the presser foot; the preset slow-descent position is a preset pause position of the presser foot; comparing the target position and the preset slow-descent position to obtain a comparison result; if the comparison result indicates that slow-descent is required, then the presser foot is lowered from the current position to the target position according to a preset slow-descent strategy; if the comparison result indicates that slow-descent is not required, then the presser foot is lowered from the current position to the target position according to a closed-loop control algorithm.

[0005] In one implementation of the first aspect, obtaining a comparison result by comparing the target position and the preset descent position includes: if the height of the target position is less than the height of the preset descent position, the comparison result indicates that descent is required; if the height of the target position is greater than or equal to the height of the preset descent position, the comparison result indicates that descent is not required.

[0006] In one implementation of the first aspect, lowering the presser foot from the current position to the target position according to a preset descent strategy includes: setting the preset target position of the presser foot to a first position at the same height as the preset descent position according to the closed-loop control algorithm; when the presser foot descents from the current position to the target position, determining whether the dwell time of the presser foot at the first position is greater than or equal to a preset time; if the dwell time is greater than or equal to the preset time, then lowering the presser foot from the first position to the target position according to the closed-loop control algorithm; if the dwell time is less than the preset time, then re-executing the setting of the preset target position of the presser foot to the first position at the same height as the preset descent position according to the closed-loop control algorithm.

[0007] In one implementation of the first aspect, before comparing the target position and the preset descent position to obtain a comparison result, the method further includes: making a judgment based on the target position and the current position to obtain a judgment result; and judging whether the pressure foot should perform a descent based on the judgment result.

[0008] In one implementation of the first aspect, determining whether the presser foot needs to be gradually lowered based on the judgment result includes: if the height of the target position is higher than the height of the current position, then the judgment result is that the presser foot does not perform gradual lowering, and the presser foot is raised from the current position to the target position according to the closed-loop control algorithm.

[0009] In one implementation of the first aspect, determining whether the presser foot needs to be slowly lowered based on the determination result includes: if the height of the target position is equal to the height of the current position, then the determination result is that the presser foot does not perform slow descent and the position of the presser foot is maintained at the current position.

[0010] In one implementation of the first aspect, determining whether the presser foot needs to be slowly lowered based on the determination result includes: if the height of the target position is lower than the height of the current position, then further determining whether the presser foot should perform a slow descent based on the target position and the preset slow descent position.

[0011] Secondly, this application provides a presser foot slow-descent control system for controlling a sewing machine. The sewing machine includes a presser foot, an electromagnet assembly, and a sensor assembly. The electromagnet assembly includes a magnet, and the sensor assembly includes a magnetic detection sensor. The magnetic detection sensor detects an electrical signal that changes linearly as the magnet moves up and down with the presser foot, so that the sewing machine can determine the current position of the presser foot based on the electrical signal. The sewing machine also includes a detection device for generating a voltage signal based on user actions, so that the sewing machine can obtain the target position of the presser foot based on the voltage signal. The system includes: an acquisition module for acquiring target data, the target data including the target position, current position, and preset slow-descent position of the presser foot; a comparison module for comparing the target position and the preset slow-descent position to obtain a comparison result; a slow-descent processing module for lowering the presser foot from the current position to the target position according to a preset slow-descent strategy if the comparison result indicates that slow-descent is required; and a non-slow-descent processing module for lowering the presser foot from the current position to the target position according to a closed-loop control algorithm if the comparison result indicates that slow-descent is not required.

[0012] Thirdly, this application provides an electronic device, which includes: a memory storing a computer program; and a processor connected to the memory, which executes the aforementioned presser foot slow-descent control method when the computer program is invoked.

[0013] Fourthly, this application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by an electronic device, implements the aforementioned presser foot slow-descent control method.

[0014] Fifthly, this application provides a sewing machine including the presser foot slow-descent control system as described above.

[0015] As described above, the presser foot slow-descent control method, system, electronic device, and sewing machine of this application have the following advantages:

[0016] Beneficial effects:

[0017] This application obtains a comparison result by comparing the target position and the preset slow-descent position. If the comparison result indicates that slow descent is required, the presser foot is lowered from the current position to the target position according to the preset slow-descent strategy. If the comparison result indicates that slow descent is not required, the presser foot is lowered from the current position to the target position according to the closed-loop control algorithm. This effectively reduces the descent speed of the presser foot when using an electromagnet to lift it, thus reducing noise. Furthermore, it has a wide range of applications and is suitable for different electromagnet-lifted presser foot models, such as flat sewing and overlock sewing machines.

[0018] This application employs a closed-loop control algorithm (PID algorithm) for presser foot slow-descent control. By using feedback from the sewing machine head height sensor, the height is adjusted in a closed loop. This allows the presser foot to pause briefly at a preset slow-descent position during its descent to reduce noise, while not affecting the normal descent of the presser foot at other positions.

[0019] This application employs a closed-loop control algorithm (PID algorithm) for presser foot slow-descent control. Feedback from the sewing machine head height sensor enables closed-loop height adjustment. The original presser foot height control responds quickly, and slow-descent has minimal impact on it. Furthermore, the existing structure that uses an electromagnet to lift the presser foot requires no modification; only the addition of a presser foot height sensor is needed, resulting in a simple structure and low cost. Attached Figure Description

[0020] Figure 1 The diagram shown is a schematic representation of the hardware structure of the sewing machine based on the electromagnet-driven presser foot mechanism described in this application embodiment.

[0021] Figure 2 The diagram shown is a flowchart illustrating the pressure foot slow-descent control method described in an embodiment of this application.

[0022] Figure 3 The diagram shown is a schematic diagram of the presser foot height control process described in the embodiments of this application.

[0023] Figure 4 The diagram shown is a schematic of the presser foot slow-descent algorithm described in an embodiment of this application.

[0024] Figure 5 The diagram shown is a structural schematic of the pressure foot slow-descent control system described in an embodiment of this application.

[0025] Figure 6 The diagram shown is a structural schematic of the electronic device described in an embodiment of this application.

[0026] Component designation explanation

[0027] 1 Electromagnet fixing parts

[0028] 2. Lifting the pressure foot electromagnet

[0029] 3. Electromagnet core

[0030] 4. Reverse rear lever joint

[0031] 5. Reverse lever

[0032] 6. Reverse lever fixed shaft

[0033] 7. Pull rod

[0034] 8. Front Lever

[0035] 9 Presser foot lifting plate

[0036] 10. Buffer Torsion Spring

[0037] 11 Torsion Spring Shaft Screw

[0038] 12 Pressure bar guide frame

[0039] 13 Magnet mounting base

[0040] 14 Sensor mounting bracket

[0041] 15 presser feet

[0042] 100 Pressure Foot Soft Closure Control System

[0043] 110 Acquisition Module

[0044] 120 Comparison Module

[0045] 130 Slow Descent Module

[0046] 140 Non-Descent Processing Module

[0047] 200 electronic devices

[0048] 210 Memory

[0049] 220 processor

[0050] Steps S1 to Sn Detailed Implementation

[0051] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. This application can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, unless otherwise specified, the following embodiments and features in the embodiments can be combined with each other.

[0052] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of this application. Therefore, the drawings only show the components related to this application and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0053] The following embodiments of this application provide a presser foot slow-descent control method, system, electronic device, and medium that solves the problem of loud impact noise generated when the presser foot of an existing sewing machine descends.

[0054] like Figure 1 As shown, this embodiment provides a sewing machine with an electromagnet lifting presser foot mechanism, specifically including: an electromagnet fixing component (1), a presser foot lifting electromagnet (2), an electromagnet core (3), a reverse rear lever connector (4), a reverse rear lever (5), a reverse rear lever fixing shaft (6), a pull rod (7), a front lever (8), a presser foot lifting plate (9), a buffer torsion spring (10), a torsion spring shaft screw (11), a presser rod guide (12), a magnet assembly (13), a sensor assembly (14), and a presser foot (15).

[0055] Among them, the presser foot electromagnet (2) is connected to the electromagnet fixing part (1) and fixed to the sewing machine housing by screws. The electromagnet core (3) can move freely up and down within the coil frame of the presser foot electromagnet (2). The rear end of the electromagnet core (3) is machined with a threaded hole. The reverse rear lever joint (4) is fixed in the threaded hole and connected to the reverse rear lever (5) by a pin. The reverse rear lever (5) is fixed to the reverse rear lever fixing part (6) by a shaft screw and can rotate freely around the shaft screw. The connecting rod ( 7) The screw is fixed to the threaded hole machined at one end of the reverse rear lever (5), and connected to the front lever (8) by the screw. The front lever (8) is connected to the presser foot lifting plate (9) by the pin. The presser foot lifting plate (9) has a threaded hole machined on it. The torsion spring shaft screw (11) is fixed in the threaded hole. The torsion spring (10) is wrapped around the torsion spring shaft screw (11) and presses one end on the presser foot lifting plate (9), and the other end abuts against the pressure rod guide frame (12), so that the presser foot lifting plate (9) and the pressure rod guide frame (12) will not be separated by the electromagnet. The iron core (3) is in contact with itself due to its own weight, maintaining a state of separation from each other, preventing noise caused by the up-and-down movement of the sewing machine feed dog during the sewing process due to the collision between the presser bar guide (12) and the presser foot lifting plate (9). A magnet assembly (13) is fixed on the presser bar guide (12). The magnet assembly (13) includes a magnet and a magnet fixing component. The magnet is set inside the magnet fixing component and can move up and down with the presser bar guide (12) as the presser foot (15) is raised and lowered. The sensor assembly (14) includes a magnetic detection sensor and a sensor fixing component. The sensor fixing component contains a magnetic detection sensor. The sensor fixing component is fixed to the sewing machine housing by screws and maintains a certain distance from the magnet on the magnet assembly (13). The magnetic detection sensor inside the sensor fixing component can detect the magnetic field generated by the magnet. When the magnet moves up and down with the presser foot (15), the magnetic detection sensor inside the sensor fixing component can output an electrical signal that changes linearly with the height of the magnet. The sewing machine master controller determines the current presser foot height based on this signal. The sewing machine master controller is used to control the operation of the sewing machine.

[0056] The technical solutions in the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0057] like Figure 2As shown, this embodiment provides a presser foot slow-descent control method applied to a sewing machine, the sewing machine including a presser foot (15), a magnet assembly 13 and a sensor assembly 14 (see...). Figure 1 The magnet assembly 13 includes a magnet and a magnet holder, the magnet holder being used to fix the magnet; the sensor assembly 14 includes a magnetic detection sensor and a sensor holder, the magnetic detection sensor being disposed within the sensor holder; the magnetic detection sensor is used to detect the linearly changing electrical signal of the magnet as the presser foot moves up and down, so that the sewing machine can determine the current position of the presser foot based on the electrical signal; the sewing machine also includes a detection device (not shown in the figure) for generating a voltage signal based on the user's actions, so that the sewing machine can obtain the target position of the presser foot based on the voltage signal.

[0058] In one embodiment, the presser foot height control principle is as follows: the user can control the presser foot height via a pedal or electronic knee rest. Generally, the pedal or electronic knee rest contains a stroke detection device, composed of a linear Hall effect sensor and a small magnet. When the pedal or knee rest is activated, the output voltage of the stroke detection device changes. The main controller samples the voltage signal from the pedal or knee rest and converts it into the target presser foot height. The real-time presser foot height is fed back by a magnetic detection sensor (height sensor) on the machine head. The presser foot height is controlled by adjusting the current in real time using a PID algorithm. Pressing the pedal backward or pushing against the knee rest raises the presser foot; the greater the backward press or the greater the pushing, the higher the presser foot rises. Releasing the pedal or knee rest lowers the presser foot; the greater the release, the greater the descent. When fully released, the presser foot completely descends. When releasing the pedal or knee rest, it is necessary to determine whether the presser foot needs to descend slowly. Slow descent is only triggered when the presser foot has descended to a relatively low height. This application achieves pressure foot slow descent control by controlling the magnitude of the electromagnet input current in conjunction with the pressure foot height sensor, and uses a PID algorithm to achieve slow descent by pausing briefly when the pressure foot passes a certain height.

[0059] like Figure 2 As shown, this embodiment provides a method for controlling the slow descent of the pressure foot, the method including the following steps S1 to S4.

[0060] Step S1: Obtain target data; the target data includes the target position, current position, and preset descent position of the presser foot.

[0061] Specifically, when the pedal or knee rest is activated, the output voltage of the detection device on the sewing machine changes. The main controller of the sewing machine samples the voltage signal from the pedal or electronic knee rest and converts the voltage signal into the target height of the presser foot, i.e., the target position of the presser foot. The current position of the presser foot is fed back by the magnetic detection sensor, i.e., the height sensor, of the sewing machine. The real-time height of the presser foot, i.e., the current position of the presser foot, can be controlled by adjusting the current in real time through a PID algorithm. The preset slow-descent position is the preset stopping position of the presser foot. The preset slow-descent position is determined by the thickness of the fabric being sewn by the sewing machine. If the height of the preset slow-descent position is too high, the presser foot will still produce a relatively large impact sound when descending from the preset slow-descent position. If the height of the preset slow-descent position is too low, then not much fabric can be placed between the presser foot and the sewing table. If the thickness of the fabric exceeds the height of the preset slow-descent position, then when the presser foot descends, it will press the fabric first and will not reach the preset slow-descent position. It will directly hit the fabric, resulting in insufficient time to perform the slow-descent and failing to achieve the slow-descent effect. Therefore, the preset slow-descent position should be set within a reasonable range. For example, the preset slow-descent position is located within the range [1.5mm, 2.5mm]. This application uses 2mm as an example for explanation, but this application is not limited to this.

[0062] Step S2: Compare the target position and the preset descent position to obtain a comparison result.

[0063] Specifically, this application compares the target position and the preset slow-descent position through the main controller of the sewing machine. If the target position is smaller than the preset slow-descent position, it indicates that slow descent is required; otherwise, slow descent is not required. A closed-loop control algorithm (e.g., PID algorithm) is executed to lower the presser foot from the current position to the target position.

[0064] In one embodiment of this application, the comparison between the target position and the preset descent position to obtain a comparison result includes the following steps S21 to S22.

[0065] Step S21: If the height of the target position is less than the height of the preset descent position, then the comparison result indicates that descent is required.

[0066] Step S22: If the height of the target position is greater than or equal to the height of the preset descent position, then the comparison result indicates that descent is not required.

[0067] Step S3: If the comparison result indicates that a slow descent is required, the pressure foot is lowered from the current position to the target position according to the preset slow descent strategy.

[0068] Specifically, if the target position is smaller than the preset descent position, a slow descent is required. First, a closed-loop control algorithm (e.g., a PID algorithm) is executed to set the preset target position of the presser foot to a first position at the same height as the preset descent position. For example, if the preset descent position is 2mm high, the preset target position of the presser foot is also set to 2mm (the current position of the presser foot is higher than the target position). It is then determined whether the presser foot remains stably in the first position for a set time, such as 1ms. If the presser foot remains stable near 2mm for 1ms, the descent speed is determined to have decreased to 0 at a height of 2mm. Subsequently, the closed-loop control algorithm (e.g., a PID algorithm) is executed, and the presser foot continues to descend to the target position. For example, if the target position is 1mm high, the presser foot will quickly descend to 1mm. If the target position is 0mm high, the presser foot will fall completely, starting its descent at 2mm, thus avoiding a loud impact sound. If the presser foot height cannot remain stable at around 2mm for 1ms, it indicates that the presser foot cannot descend slowly at the 2mm position. The closed-loop control algorithm (e.g., PID algorithm) should be re-executed to set the preset target position of the presser foot.

[0069] It should be noted that the closed-loop control algorithm is not limited to the PID algorithm and can also be implemented by other closed-loop algorithms; this application is not limited to this. Furthermore, the preset descent position height is not limited to 2mm; users can set it according to actual conditions, and this application is not limited to this.

[0070] In one embodiment of this application, lowering the presser foot from the current position to the target position according to a preset descent strategy includes the following steps S31 to S34.

[0071] Step S31: According to the closed-loop control algorithm, set the preset target position of the presser foot to a first position at the same height as the preset slow-descent position;

[0072] Step S32: When the presser foot slowly descends from the current position to the target position, determine whether the dwell time of the presser foot at the first position is greater than or equal to a set time.

[0073] Specifically, the set time is the presser foot dwell time, which can be tens or hundreds of microseconds, and this application is not limited to this. The setting of the presser foot dwell time is related to the MCU's processing speed and the sampling frequency of the height sensor. In this application, the presser foot dwell time is illustrated using 1 ms as an example. For the presser foot dwell time, it is sufficient to determine that the presser foot speed has dropped to 0. In principle, the time should be as short as possible, while still being able to determine that the presser foot has stopped.

[0074] Step S33: If the dwell time is greater than or equal to the set time, then the presser foot is lowered from the first position to the target position according to the closed-loop control algorithm;

[0075] Step S34: If the dwell time is less than the set time, then re-execute the closed-loop control algorithm to set the preset target position of the presser foot to a first position at the same height as the preset descent position.

[0076] Step S4: If the comparison result indicates that a gradual descent is not required, the pressure foot will be lowered from the current position to the target position according to the closed-loop control algorithm.

[0077] Specifically, if the target position is greater than or equal to the preset descent position, it means that descent is not required, and the closed-loop control algorithm is executed directly to lower the pressure foot from the current position to the target position.

[0078] This application achieves pressure foot slow descent control by controlling the magnitude of the electromagnet input current in conjunction with the pressure foot height sensor, and uses a PID algorithm to achieve slow descent by pausing briefly when the pressure foot passes a certain height.

[0079] In one embodiment of this application, before comparing the target position and the preset descent position to obtain a comparison result, the method further includes the following steps S11 to S12.

[0080] Step S11: Make a judgment based on the target location and the current location to obtain a judgment result;

[0081] Step S12: Determine whether the pressure foot should perform a slow descent based on the judgment result.

[0082] Specifically, determining whether the presser foot needs to be lowered requires judging the target position and the current position of the presser foot. If the target position is higher than the current position, the presser foot needs to be raised to reach the target position. In this case, lowering is not required; this application uses a closed-loop control algorithm (PID algorithm) to raise the presser foot to the target position. If the target position and the current position are at the same height, the height can be kept constant, and lowering is not required. If the target position is lower than the current position, step S2 needs to be executed to determine whether the presser foot needs to be lowered based on the target position and the preset lowering position, and steps S3 to S4 are executed based on the comparison result in step S2.

[0083] It should be noted that the prerequisite for the above steps S2-S4 is that the target position of the presser foot is lower than the current position.

[0084] In one embodiment of this application, determining whether the presser foot should perform a slow descent based on the determination result includes step S121A: if the height of the target position is higher than the height of the current position, then the determination result is that the presser foot should not perform a slow descent, and the presser foot is raised from the current position to the target position according to the closed-loop control algorithm.

[0085] In one embodiment of this application, determining whether the presser foot should perform a slow descent based on the determination result includes step S121B: if the height of the target position is equal to the height of the current position, then the determination result is that the presser foot should not perform a slow descent, and the position of the presser foot should be maintained at the current position.

[0086] In one embodiment of this application, determining whether the presser foot should perform a slow descent based on the determination result includes step S121C: if the height of the target position is lower than the height of the current position, then further determining whether the presser foot should perform a slow descent based on the target position and the preset slow descent position.

[0087] This application illustrates the overall process of the pressure foot slow-descent control method described in this application through one embodiment. For example... Figure 3 As shown, this is a flowchart illustrating the presser foot height control process according to an embodiment of this application. Figure 4 As shown, it is displayed as Figure 4 The flowchart of the pressure foot slow descent algorithm is shown below.

[0088] like Figure 3 As shown, the presser foot height control process includes the following steps S51 to S58.

[0089] Step S51: The user can control the presser foot height via the pedal or electronic knee rest. This application collects the voltage value of the pedal or electronic knee rest through the main control of the sewing machine and converts the voltage signal into the target height of the presser foot (the height of the target position of the presser foot).

[0090] Specifically, the pedal and electronic knee rest are equipped with a travel sensor, such as a linear Hall effect device containing a magnetic object, and the voltage value collected by the pedal or electronic knee rest is the Hall output.

[0091] Step S52: Determine whether the target height of the presser foot is greater than the actual height (the current height of the presser foot).

[0092] Step S53: If the target height is higher than the actual height, there is no need to perform a slow descent. This application uses a closed-loop control algorithm (PID algorithm) to raise the pressure foot to the target height.

[0093] Step S54: Determine whether the target height of the presser foot is equal to the actual height (the current height of the presser foot).

[0094] Step S55: If the target height is the same as the actual height, then the height can be kept unchanged and there is no need to perform a slow descent.

[0095] Step S56: If the target height is lower than the actual height, further determine whether the presser foot needs to be lowered slowly. If the target height is lower than the actual height, then step S2 needs to be executed to determine whether the presser foot should be lowered slowly based on the target position and the preset slow-descent position.

[0096] Step S57: If the target position is smaller than the preset descent position, the comparison result indicates that descent is required. The pressure foot is lowered from the current position to the target position according to the preset descent strategy (see [reference]). Figure 4 ).

[0097] Step S58: If the target position is greater than or equal to the preset descent position, the comparison result indicates that descent is not required. The pressure foot is lowered from the current position to the target position by executing a closed-loop control algorithm (e.g., PID algorithm).

[0098] Because the presser foot slow-descent of the electromagnet requires closed-loop adjustment, closed-loop adjustment has the following problems. First, because the compression of the spring varies, the downward force on the presser foot differs, and the electromagnet current required for slow descent also varies. Current technology involves manually rotating the adjusting nut on the top of the sewing machine to change the spring compression, but the main controller cannot recognize the scale on the adjusting nut. Second, the electromagnet heats up after prolonged energization, leading to a decrease in suction force. The greater the heat, the smaller the suction force produced by the same current. Therefore, the presser foot slow-descent of the electromagnet cannot be controlled in an open-loop manner; closed-loop control is required.

[0099] However, considering the hysteresis effect of the electromagnet and the inability of the coil current to change abruptly, the closed-loop control results in a slow dynamic response and an uneven, stepped presser foot height curve. This means it's impossible to precisely control the electromagnet's speed through a closed loop, making it difficult to achieve a smooth curve where the speed decreases as the height decreases during descent. This application addresses this by using a closed-loop algorithm to reduce the presser foot speed to zero when it reaches a certain height before continuing its descent. Specifically, this application employs a closed-loop control algorithm (e.g., PID algorithm) for presser foot slow-descent control, using feedback from the sewing machine's head height sensor for closed-loop height adjustment.

[0100] It should be noted that the smooth curve of decreasing speed at lower altitudes during descent refers to the maximum descent speed of the presser foot after it has descended to a very low position, such as within the 0-2mm range. The lower the position, the slower the maximum descent speed. The complete descent process is as follows: initially, the presser foot can descend rapidly, but it begins to decelerate after reaching a certain height, and the speed decreases further as it descends. If the target speed controlled by the pedal and knee rest exceeds this maximum speed, the descent will proceed at the maximum speed. This control method balances presser foot response speed and gradual descent, which is the desired effect of this application.

[0101] like Figure 4 As shown, the presser foot slow-descent algorithm process includes the following steps S61 to S65.

[0102] Step S61: First, this application uses the main control of the sewing machine to determine the height of the target position and the height of the preset slow-descent position. The height of the preset slow-descent position is 2mm as an example. When the target position of the presser foot is adjusted from above 2mm to below 2mm, that is, when the height of the target position is less than the height of the preset slow-descent position, it indicates that slow-descent is required.

[0103] Step S62: If the height of the target position is greater than or equal to the height of the preset descent position, then descent is not required. The pressure foot is lowered from the current position to the target position by executing a closed-loop control algorithm (e.g., PID algorithm).

[0104] Step S63: By executing a closed-loop control algorithm (e.g., PID algorithm), the preset target position of the presser foot is set to 2mm (the current position of the presser foot is higher than the target position).

[0105] Step S64: Determine whether the presser foot height remains stably around 2mm for 1ms. If the presser foot height remains stable around 2mm for 1ms, it is determined that the presser foot descent speed decreases to 0 at the 2mm height. If the presser foot height cannot remain stable around 2mm for 1ms, it indicates that the presser foot cannot descend slowly at the 2mm position. The closed-loop control algorithm (e.g., PID algorithm) is re-executed to set the preset target position of the presser foot.

[0106] Step S65: Subsequently, a closed-loop control algorithm (e.g., a PID algorithm) is executed, and the pressure foot continues to descend to the target position. For example, if the target position is 1mm high, the pressure foot will quickly descend to 1mm high. If the target position is 0mm high, the pressure foot will fall completely, starting to fall at a height of 2mm, thus avoiding a loud impact sound.

[0107] It should be noted that a slow descent will be triggered whenever the presser foot target position is adjusted from above 2mm to below 2mm, because it is impossible to predict whether the user will completely lower the presser foot.

[0108] Users might control the presser foot to descend rapidly until it's fully lowered, or they might simply want to quickly lower it to a lower height, such as 1mm or 0.5mm, and then maintain that height. If the target height of the presser foot is 1mm or 0.5mm, regardless of the initial height of the presser foot or the speed at which the user releases the pedal or rests their knee, the presser foot will eventually hover at 1mm or 0.5mm under the control of the closed-loop algorithm, in which case no impact sound will be produced. If the presser foot continues to descend rapidly to 0mm after passing a height of 1mm or 0.5mm, a loud impact sound will be produced.

[0109] This application employs a PID algorithm for presser foot slow-descent control. Based on feedback from the sewing machine head height sensor, closed-loop height adjustment is performed. When the presser foot reaches a certain height, the closed-loop algorithm reduces the presser foot speed to 0 before continuing to descend. This effectively reduces the presser foot descent speed and noise when the electromagnet lifts the presser foot.

[0110] The protection scope of the pressure foot slow-descent control method described in this application is not limited to the execution order of the steps listed in this embodiment. Any solution implemented by adding, subtracting, or replacing steps in the prior art based on the principles of this application is included within the protection scope of this application.

[0111] This application also provides a presser foot slow-descent control system, which can implement the presser foot slow-descent control method described in this application. However, the implementation device of the presser foot slow-descent control method described in this application includes, but is not limited to, the structure of the presser foot slow-descent control system listed in this embodiment. All structural modifications and substitutions of the prior art made based on the principles of this application are included within the protection scope of this application.

[0112] like Figure 5 As shown, this embodiment provides a presser foot slow-descent control system for controlling a sewing machine. The sewing machine includes a presser foot, an electromagnet assembly, and a sensor assembly. The electromagnet assembly includes a magnet, and the sensor assembly includes a magnetic detection sensor. The magnetic detection sensor detects the linearly changing electrical signal of the magnet as the presser foot moves up and down, so that the sewing machine can determine the current position of the presser foot based on the electrical signal. The sewing machine also includes a detection device for generating a voltage signal based on user actions, so that the sewing machine can obtain the target position of the presser foot based on the voltage signal. The system 100 includes: an acquisition module 110, a comparison module 120, a slow-descent processing module 130, and a non-slow-descent processing module 140.

[0113] The acquisition module 110 is used to acquire target data; the target data includes the target position, current position, and preset descent position of the presser foot.

[0114] The comparison module 120 is used to compare the target position and the preset descent position to obtain a comparison result;

[0115] The slow descent processing module 130 is used to lower the pressure foot from the current position to the target position according to a preset slow descent strategy if the comparison result indicates that slow descent is required.

[0116] The non-gradient descent processing module 140 is used to lower the pressure foot from the current position to the target position according to the closed-loop control algorithm if the comparison result indicates that gradient descent is not required.

[0117] It should be noted that the functions or operations of the acquisition module 110, comparison module 120, slow-descent processing module 130 and non-slow-descent processing module 140 described in this embodiment correspond one-to-one with the steps in the above-described method for slow-descent control of the presser foot, and therefore will not be repeated here.

[0118] In the embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, or methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative. For instance, the division of modules / units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple modules or units may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection of apparatuses or modules or units may be electrical, mechanical, or other forms.

[0119] The modules / units described as separate components may or may not be physically separate. The components shown as modules / units may or may not be physical modules; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules / units can be selected to achieve the objectives of the embodiments of this application, depending on actual needs. For example, the functional modules / units in the various embodiments of this application may be integrated into one processing module, or each module / unit may exist physically separately, or two or more modules / units may be integrated into one module / unit.

[0120] 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 implementation should not be considered beyond the scope of this application.

[0121] In one embodiment of this application, a sewing machine is provided, including the presser foot slow-descent control system as described above.

[0122] like Figure 6 As shown, this embodiment provides an electronic device, the electronic device 200 including: a memory 210 and a processor 220.

[0123] The memory 210 stores a computer program;

[0124] The processor 220 is connected to the memory 210 and executes the aforementioned foot descent control method when the computer program is invoked. This application also provides a computer-readable storage medium. Those skilled in the art will understand that all or part of the steps in the methods of the above embodiments can be implemented by a program instructing a processor. The program can be stored in a computer-readable storage medium, which is a non-transitory medium, such as random access memory, read-only memory, flash memory, hard disk, solid-state drive, magnetic tape, floppy disk, optical disk, and any combination thereof. The aforementioned storage medium can be any available medium accessible to a computer or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., digital video disc (DVD)), or a semiconductor medium (e.g., solid-state disk (SSD)).

[0125] This application embodiment may also provide a computer program product comprising one or more computer instructions. When the computer instructions are loaded and executed on a computing device, all or part of the processes or functions described in this application embodiment are generated. The computer instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions may be transmitted from one website, computer, or data center to another via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means.

[0126] When the computer program product is executed by a computer, the computer performs the method described in the foregoing method embodiments. The computer program product can be a software installation package; when the foregoing method is required, the computer program product can be downloaded and executed on the computer.

[0127] In summary, the presser foot slow-descent control method, system, electronic device, and sewing machine described in the above embodiments of this application have the following beneficial effects:

[0128] This application obtains a comparison result by comparing the target position and the preset slow-descent position. If the comparison result indicates that slow descent is required, the presser foot is lowered from the current position to the target position according to the preset slow-descent strategy. If the comparison result indicates that slow descent is not required, the presser foot is lowered from the current position to the target position according to the closed-loop control algorithm. This effectively reduces the descent speed of the presser foot when using an electromagnet to lift it, thus reducing noise. Furthermore, it has a wide range of applications and is suitable for different electromagnet-lifted presser foot models, such as flat sewing and overlock sewing machines.

[0129] This application employs a closed-loop control algorithm (PID algorithm) for presser foot slow-descent control. By using feedback from the sewing machine head height sensor, the height is adjusted in a closed loop. This allows the presser foot to pause briefly at a preset slow-descent position during its descent to reduce noise, while not affecting the normal descent of the presser foot at other positions.

[0130] This application employs a closed-loop control algorithm (PID algorithm) for presser foot slow-descent control. Feedback from the sewing machine head height sensor enables closed-loop height adjustment. The original presser foot height control responds quickly, and slow-descent has minimal impact on it. Furthermore, the existing structure that uses an electromagnet to lift the presser foot requires no modification; only the addition of a presser foot height sensor is needed, resulting in a simple structure and low cost.

[0131] The descriptions of the processes or structures corresponding to the above figures each have their own emphasis. For parts of a process or structure that are not described in detail, please refer to the relevant descriptions of other processes or structures.

[0132] The above embodiments are merely illustrative of the principles and effects of this application and are not intended to limit this application. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this application. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this application should still be covered by the claims of this application.

Claims

1. A presser foot slow descent control method characterized by, The method comprises: acquiring target data; the target data comprises a target position, a current position and a preset slow descent position of a presser foot; the preset slow descent position is a preset pause position of the presser foot; comparing the target position and the preset slow descent position to obtain a comparison result; if the height of the target position is less than the height of the preset slow descent position, the comparison result indicates that slow descent is needed; if the height of the target position is greater than or equal to the height of the preset slow descent position, the comparison result indicates that slow descent is not needed; if the comparison result indicates that slow descent is needed, lowering the presser foot from the current position to the target position according to a preset slow descent strategy; step S31: setting a temporary control target of the presser foot as a first position at the same height as the preset slow descent position, and controlling movement of the presser foot according to a closed-loop control algorithm; step S32: when the presser foot moves to the vicinity of the first position, determining whether a stay time of the presser foot in the vicinity of the first position is greater than or equal to a set time; step S33: if the stay time is greater than or equal to the set time, lowering the presser foot from the first position to the target position according to the closed-loop control algorithm; step S34: if the stay time is less than the set time, returning to step S31 to re-perform slow descent control; if the comparison result indicates that slow descent is not needed, lowering the presser foot from the current position to the target position according to a closed-loop control algorithm.

2. The presser foot descent control method according to claim 1, characterized by, Before comparing the target position and the preset slow descent position to obtain a comparison result, the method further comprises: determining the target position and the current position to obtain a determination result; determining, according to the determination result, whether the presser foot performs slow descent.

3. The presser foot descent control method according to claim 2, characterized by, Determining, according to the determination result, whether the presser foot performs slow descent comprises: if the height of the target position is higher than the height of the current position, the determination result is that the presser foot does not perform slow descent, and the presser foot is raised from the current position to the target position according to the closed-loop control algorithm.

4. The presser foot descent control method according to claim 2, characterized by, Determining, according to the determination result, whether the presser foot performs slow descent comprises: if the height of the target position is equal to the height of the current position, the determination result is that the presser foot does not perform slow descent, and the position of the presser foot is maintained at the current position.

5. The presser foot descent control method according to claim 2, characterized by, Determining, according to the determination result, whether the presser foot performs slow descent comprises: if the height of the target position is lower than the height of the current position, further determining, according to the target position and the preset slow descent position, whether the presser foot performs slow descent.

6. A presser foot slow descent control system characterized by, The system comprises: an acquisition module configured to acquire target data; the target data comprises a target position, a current position and a preset slow descent position of a presser foot; a comparison module configured to compare the target position and the preset slow descent position to obtain a comparison result; if the height of the target position is less than the height of the preset slow descent position, the comparison result indicates that slow descent is needed; if the height of the target position is greater than or equal to the height of the preset slow descent position, the comparison result indicates that slow descent is not needed; The slow descent processing module is configured to, if the comparison result indicates that slow descent is needed, lower the presser from the current position to the target position according to a preset slow descent strategy; step S31: set a temporary control target of the presser as a first position at the same height as the preset slow descent position, and control the movement of the presser according to the closed-loop control algorithm; step S32: when the presser moves to the vicinity of the first position, determine whether a stay time of the presser in the vicinity of the first position is greater than or equal to a set time; step S33: if the stay time is greater than or equal to the set time, lower the presser from the first position to the target position according to the closed-loop control algorithm; step S34: if the stay time is less than the set time, return to step S31 to re-execute slow descent control; The non-slow descent processing module is configured to, if the comparison result indicates that slow descent is not needed, lower the presser from the current position to the target position according to a closed-loop control algorithm.

7. An electronic device, comprising: The electronic device comprises: a memory storing a computer program; a processor connected to the memory, which invokes the computer program to execute the presser slow descent control method according to any one of claims 1 to 5.

8. A sewing machine characterized by comprising: The presser slow descent control system according to claim 6. The presser slow descent control system according to claim 6.

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