A yarn tension control method

Abstract

The present application relates to the technical field of electronic circuit, particularly relates to a yarn tension control method, the method is applied to yarn tension control system, the system includes industrial computer and a plurality of strapdown units, the industrial computer is connected with each strapdown unit, each strapdown unit includes at least one motor, each motor is connected to a yarn;The method comprises: using the industrial computer to send the preset yarn tension to each strapdown unit;Using each strapdown unit respectively based on the received yarn tension control corresponding motor output torque;Using each motor respectively to provide tension for corresponding yarn.The method can quickly, stably adjust the tension of yarn, improve the production quality of fabric.

Description

Technical Field

[0001] This invention relates to the field of electronic circuit technology, and in particular to a method for controlling yarn tension. Background Technology

[0002] With the advancement of technology, textile factories are constantly expanding in scale. When producing fabrics, tens of thousands of yarns are needed simultaneously, and different yarns may have different tensions during operation. Therefore, controlling the tension of each yarn is a major engineering project.

[0003] In related technologies, mechanical control methods, such as weighted or spring-loaded systems, are often used. With these methods, when adjusting yarn tension, workers must first locate the corresponding yarn and then manually change the weight of the weight on the yarn or adjust the spring's tension. This not only consumes a lot of manpower but also introduces errors, leading to unstable yarn tension and consequently affecting fabric quality.

[0004] Therefore, there is an urgent need for a yarn tension control method to solve the above-mentioned technical problems. Summary of the Invention

[0005] This invention provides a yarn tension control method that can quickly and stably adjust yarn tension and improve fabric production quality.

[0006] This invention provides a yarn tension control method applied to a yarn tension control system. The system includes an industrial computer and multiple strapdown units. The industrial computer is communicatively connected to each strapdown unit. Each strapdown unit includes at least one motor, and each motor is connected to a yarn. The method includes:

[0007] The industrial control computer sends a preset yarn tension to each of the strapdown units;

[0008] Each strapdown unit controls the output torque of its corresponding motor based on the received yarn tension.

[0009] Each of the motors is used to provide tension to the corresponding yarn.

[0010] In one possible design, the yarn tension control system further includes a first switch, the input port of which is connected to the industrial computer via a bus of preset capacity, and the output port is connected to each of the strapdown units via an Ethernet bus.

[0011] The step of sending a preset yarn tension to each strapdown unit using the industrial control computer includes:

[0012] The industrial control computer is used to transmit the preset yarn tension to the first switch;

[0013] The preset yarn tension is sent to the corresponding strapdown unit using the first switch.

[0014] In one possible design, each strapdown unit includes multiple control boards connected in sequence. Each control board includes a second switch, a PHY, a main MCU, and multiple control circuits. The second switch is connected in series with the second switches of its adjacent control boards. The PHY is connected to both the second switch and the main MCU. The main MCU is communicatively connected to each of the control circuits. Each control circuit is connected to a motor.

[0015] The method of controlling the output torque of the corresponding motor of each strapdown unit based on the received yarn tension includes:

[0016] Each of the control boards is connected in series using each of the second switches, so that the preset yarn tension is transmitted to each of the control boards respectively;

[0017] For each of the control boards, the current main MCU uses the received yarn tension to control the working state of each corresponding control circuit in order to control the output torque of the corresponding motor.

[0018] In one possible design, each of the control circuits includes: a current acquisition module, a rotor position acquisition module, a control unit, a drive circuit, and a motor; wherein the input terminal of the current acquisition module is connected to the drive circuit, and the output terminal is connected to the control unit; the input terminal of the rotor position acquisition module is connected to the motor, and the output terminal is connected to the control unit; the control unit is connected to the drive circuit, and the output terminal of the drive circuit is connected to the motor.

[0019] The method of using the current main MCU to control the working state of each corresponding control circuit based on the received yarn tension, in order to control the output torque of the corresponding motor, includes:

[0020] For each of the aforementioned control circuits, the following is executed:

[0021] The current flowing through the drive circuit is collected using the current acquisition module;

[0022] The rotor position of the motor is obtained using the rotor position acquisition module;

[0023] The control unit receives the yarn tension sent by the main MCU, and outputs a first control signal to the drive circuit based on the yarn tension, the current acquired by the current acquisition module, and the rotor position acquired by the rotor position acquisition module.

[0024] The drive circuit controls the output torque of the corresponding motor according to the level state of the first control signal.

[0025] In one possible design, the control unit includes an operational amplifier and an analog-to-digital converter;

[0026] The current acquisition module includes a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, and a sixth resistor;

[0027] One end of the first resistor is connected to the driving circuit and one end of the second resistor, the other end of the first resistor is connected to one end of the third resistor, the other end of the second resistor is connected to one end of the fifth resistor, one end of the sixth resistor and the non-inverting input terminal of the operational amplifier, the other end of the third resistor is connected to one end of the fourth resistor and the inverting input terminal of the operational amplifier, the output terminal of the operational amplifier is connected to the other end of the fourth resistor and the analog-to-digital converter, the other end of the fifth resistor is grounded, and the other end of the sixth resistor is connected to the power supply.

[0028] The step of acquiring the current flowing through the drive circuit using the current acquisition module includes:

[0029] Obtain the voltage across the first resistor;

[0030] The acquired voltage is amplified by a preset factor using the operational amplifier to obtain the amplified voltage;

[0031] The control unit uses the amplified voltage to determine the current flowing through the drive circuit.

[0032] In one possible design, the current acquisition module further includes a seventh resistor and a first capacitor; one end of the seventh resistor is connected to the output terminal of the operational amplifier and the other end of the fourth resistor, the other end of the seventh resistor is connected to the analog-to-digital converter and one end of the first capacitor, and the other end of the first capacitor is grounded;

[0033] The step of using the control unit to determine the current flowing through the drive circuit based on the amplified voltage includes:

[0034] The amplified voltage is low-pass filtered using the seventh resistor and the first capacitor to remove glitches and noise from the voltage waveform.

[0035] The analog-to-digital converter is used to convert the noise-filtered voltage signal from an analog signal into a digital signal.

[0036] The control unit uses the received digital signal to determine the current flowing through the drive circuit.

[0037] In one possible design, the motor is a three-phase motor, the control unit further includes an analog comparator, and the rotor position acquisition module includes three parallel signal sampling circuits, each of which includes an eighth resistor, a ninth resistor, and a second capacitor.

[0038] One end of each of the eighth resistors is connected to the motor, and the other end is connected to the analog comparator. One end of the ninth resistor is connected to the motor, and the other end of the ninth resistor is connected to one end of the eighth resistor and one end of the second capacitor. The other end of the eighth resistor is connected to the analog comparator, and the other end of the second capacitor is grounded.

[0039] The step of obtaining the rotor position of the motor using the rotor position acquisition module includes:

[0040] The three signal values ​​of the Hall sensor are collected based on the three eighth resistors respectively;

[0041] The RC filter circuit composed of the ninth resistor and the second capacitor is used to filter out noise in each signal value;

[0042] The analog comparator determines the rotor position of the motor at the current moment based on the signal value after noise is filtered out.

[0043] In one possible design, the step of receiving the yarn tension sent by the main MCU using the control unit, and outputting a first control signal to the drive circuit based on the yarn tension, the current acquired by the current acquisition module, and the rotor position acquired by the rotor position acquisition module, includes:

[0044] The control unit determines the reference current flowing through the motor based on the received yarn tension;

[0045] Calculate the difference between the reference current and the current acquired by the current acquisition module;

[0046] The commutation point of the motor is determined based on the rotor position acquired by the rotor position acquisition module;

[0047] Based on the calculated current difference and commutation point, a first control signal is output to the drive circuit.

[0048] In one possible design, the driving circuit includes a gate driver and a three-way driving bridge circuit, each of which includes two MOSFETs, a tenth resistor, and an eleventh resistor.

[0049] The gate driver's input is connected to the control unit, and the gate driver's output is connected to one end of each of the tenth resistors and one end of each of the eleventh resistors. The other end of each of the tenth resistors and the other end of each of the eleventh resistors are connected to the gate G of a MOS transistor. The drain D of each MOS transistor is connected to a coil port of the motor. The gate driver is used to amplify the control signal output by the control unit.

[0050] The step of controlling the output torque of the corresponding motor using the drive circuit according to the level state of the first control signal includes:

[0051] The first control signal is amplified to a preset value using the gate driver;

[0052] The on / off state and on / off time of each MOS transistor are controlled based on the amplified signal to control the output torque of the corresponding motor.

[0053] In one possible design, the industrial computer is also used to send an alarm signal to each of the strapdown units, each of the strapdown units is also used to send the alarm signal to the main MCU of each of the control boards, and the main MCU is also used to output a second control signal to the control circuit based on the received alarm signal.

[0054] The control circuit is also used to control the motor to turn off based on the level state of the second control signal.

[0055] This invention employs an electronic tension control method applied to a yarn control system. When yarn tension needs adjustment, the industrial control computer first sends a preset yarn tension value to the corresponding strapdown unit. Upon receiving the tension value, the strapdown unit controls the output torque of the corresponding motor, thereby providing the yarn with the required tension. This control method eliminates the need for manual operation; instead, it utilizes the industrial control computer and motors to achieve tension adjustment through circuit control. Therefore, it enables rapid and stable adjustment of yarn tension, improving fabric production quality. Attached Figure Description

[0056] 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 some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0057] Figure 1 This is a flowchart of a yarn tension control method provided in one embodiment of the present invention;

[0058] Figure 2 This is a schematic diagram of the yarn tension control system provided in one embodiment of the present invention;

[0059] Figure 3 This is a schematic diagram of the yarn tension control system provided in another embodiment of the present invention;

[0060] Figure 4 This is a schematic diagram of the yarn tension control system provided in another embodiment of the present invention;

[0061] Figure 5 This is a schematic diagram of the structure of a control board provided in one embodiment of the present invention;

[0062] Figure 6 This is a schematic diagram of the control circuit provided in one embodiment of the present invention;

[0063] Figure 7 This is a schematic diagram of the control circuit provided in another embodiment of the present invention;

[0064] Figure 8 This is a schematic diagram of the control circuit provided in another embodiment of the present invention;

[0065] Figure 9 This is a schematic diagram of the control circuit provided in another embodiment of the present invention. Detailed Implementation

[0066] 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 some embodiments of the present invention, but not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0067] Please refer to Figure 1 This invention provides a flowchart of a yarn tension control method, applicable to, for example... Figure 2 The yarn tension control system shown includes an industrial computer 1 and multiple strapdown units 2. The industrial computer 1 is communicatively connected to each strapdown unit 2. Each strapdown unit 2 includes at least one motor 21, and each motor 21 is connected to a yarn. The method includes:

[0068] Step 100: Use the industrial computer 1 to send a preset yarn tension to each strapdown unit 2;

[0069] Step 102: Each strapdown unit 2 controls the output torque of the corresponding motor 21 based on the received yarn tension.

[0070] Step 104: Use each motor 21 to provide tension to the corresponding yarn.

[0071] This invention employs an electronic tension control method. When yarn tension needs adjustment, the industrial control computer 1 first sends a preset yarn tension to the corresponding strapdown unit 2. Upon receiving the yarn tension, the strapdown unit 2 controls the output torque of the corresponding motor 21 based on the tension value, thereby providing the yarn with the required tension. This control method eliminates the need for manual operation; instead, it utilizes the industrial control computer 1 and the motor 21 to achieve tension adjustment through circuit control. Therefore, it enables rapid and stable adjustment of yarn tension, improving fabric production quality.

[0072] The following is a detailed description Figure 1 The execution method of each step is shown.

[0073] First, for step 100, the industrial control computer 1 sends a preset yarn tension to each strapdown unit 2.

[0074] In practical applications, the yarn control system includes multiple strapdown units 2, each containing at least one motor 21, each motor 21 providing tension to the yarn. During fabric production, the required yarn tension is first set and then sent to each strapdown unit 2 by the industrial control computer 1. Of course, since the required tension for each yarn may differ, the yarn tension sent to each strapdown unit 2 may also differ. During operation, when it is necessary to change the tension of the yarn corresponding to certain strapdown units 2, the industrial control computer 1 simply sends the changed tension value to the corresponding strapdown unit 2. Therefore, the tension adjustment of this invention is entirely controlled by the industrial control computer 1, without requiring manual adjustment. Thus, it enables rapid and stable adjustment of yarn tension, improving the quality of fabric production.

[0075] In some implementations, when the number of yarns is small, the number of strapdown units 2 is also small. In this case, the industrial control computer 1 can communicate with each strapdown unit 2 through a router. However, when the textile scale is large, such as when the number of yarns exceeds 10,000, the number of strapdown units 2 required is also large. In this case, using a router will limit the network scale and access speed, and cannot meet the communication requirements.

[0076] To solve the above problems, such as Figure 3As shown, the yarn tension control system also includes a first switch 3. The input port of the first switch 3 is connected to the industrial computer 1 through a bus with a preset capacity, and the output port is connected to each strapdown unit 2 through an Ethernet bus.

[0077] The industrial computer 1 sends a preset yarn tension to each strapdown unit 2, including:

[0078] The industrial control computer 1 transmits the preset yarn tension to the first exchange 3;

[0079] The preset yarn tension is sent to the corresponding strapdown unit 2 using the first switch 3.

[0080] This step employs industrial Ethernet communication technology. The first switch 3 is preferably an Ethernet industrial switch. The industrial computer 1 transmits the corresponding yarn tension to the corresponding input port of the first switch 3. Then, the first switch 3 transmits the corresponding yarn tension to the corresponding output port, and through this output port, sends the yarn tension to the corresponding strapdown unit 2. For example, when it is necessary to change the tension of the third strapdown unit 2, the corresponding tension is sent to the third strapdown unit 2 through the corresponding port of the first switch 3, thus achieving local tension control. It is evident that the first switch 3 can control different strapdown units 2 separately, and it facilitates the expansion of the strapdown units 2. Furthermore, the preset capacity bus can be a gigabit bus. By using a gigabit bus, the communication rate of each strapdown unit 2 can reach 100 Mbps. In application scenarios with the same data throughput, it has significant advantages in terms of low data loss and low latency, providing excellent real-time control for industrial knitting control equipment.

[0081] Then, for step 102, each strapdown unit 2 controls the output torque of the corresponding motor 21 based on the received yarn tension.

[0082] In this step, such as Figure 4 and Figure 5 As shown, each strapdown unit 2 includes multiple control boards 4 connected in sequence. Each control board 4 includes a second switch 41, a PHY 42, a main MCU, and multiple control circuits 44. The second switch 41 is connected in series with the second switch 41 of its adjacent control board 4. The PHY 42 is connected to the second switch 41 and the main MCU respectively. The main MCU is connected to each control circuit 44. Each control circuit 44 is connected to a motor 21.

[0083] Each strapdown unit 2 controls the output torque of its corresponding motor 21 based on the received yarn tension, including:

[0084] Each control board 4 is connected in series using each second switch 41 to transmit the preset yarn tension to each control board 4 respectively;

[0085] For each control board 4, the current main MCU uses the received yarn tension to control the working state of each corresponding control circuit 44, so as to control the output torque of the corresponding motor 21.

[0086] In this step, multiple control boards 4 are connected in series through the second switch 41 to form a strapdown unit 2. The strapdown unit 2 can send the received yarn tension to each control board 4, and then the main MCU of the control board 4 controls each motor 21, thereby controlling the output torque of each motor 21.

[0087] In some implementations, the interface of the second switch 41 can be an RJ45 interface, which connects to the adjacent control board 4. It is understood that for the first control board 4 in each strapdown unit 2, the interface of its second switch 41 is also used to connect to the output port of the first switch 3 or the Ethernet bus. It should also be noted that each strapdown unit 2 and each control board 4 has an independent IP address, each IP address corresponding to a specific physical location. Each IP address can be changed at any time by the industrial computer 1. Even in the event of a single-path failure, it can be replaced by updating the IP address, facilitating maintenance and saving time and costs for industrial production. Furthermore, the overall communication architecture of this invention enables simultaneous control of all strapdown units 2, and also supports tension adjustment control at the physical layer level, tension adjustment control at the single control board 4 level, and tension adjustment control of a single motor 21, to meet various different application scenarios.

[0088] This not only facilitates the industrial control computer 1 to individually control each strapdown unit 2 and each control board 4, but also...

[0089] In actual operation of an electric motor, the output force F = B × L × N × I, and the output torque W = F × d. Here, B is the magnet strength, L is the length of the stator coil cutting the magnetic field lines, N is the number of coil turns, I is the current flowing through the motor coil, and d is the lever arm. It is clear that for a given motor, the magnet strength, the length of the stator coil cutting the magnetic field lines, the number of coil turns, and the lever arm are fixed. Therefore, the output force and torque of the motor are directly proportional to the current. In other words, to achieve a constant output force and torque, a constant current must be maintained. Therefore, the inventors proposed controlling the output torque of the motor by controlling the current flowing through it.

[0090] Based on the above concept, in some implementation methods, such as Figure 6As shown, each control circuit 44 includes: a current acquisition module 441, a rotor position acquisition module 442, a control unit 443, a drive circuit 444, and a motor 21; wherein, the input terminal of the current acquisition module 441 is connected to the drive circuit 444, and the output terminal is connected to the control unit 443; the input terminal of the rotor position acquisition module 442 is connected to the motor 21, and the output terminal is connected to the control unit 443; the control unit 443 is connected to the drive circuit 444; and the output terminal of the drive circuit 444 is connected to the motor 21.

[0091] The main MCU uses the received yarn tension to control the operating state of each corresponding control circuit 44, thereby controlling the output torque of the corresponding motor 21, including:

[0092] For each control circuit 44, the following is executed:

[0093] The current flowing through the drive circuit 444 is collected using the current acquisition module 441;

[0094] The rotor position of motor 21 is obtained using rotor position acquisition module 442;

[0095] The control unit 443 receives the yarn tension sent by the main MCU, and outputs the first control signal to the drive circuit 444 based on the yarn tension, the current collected by the current acquisition module 441 and the rotor position collected by the rotor position acquisition module 442.

[0096] The drive circuit 444 controls the output torque of the corresponding motor 21 according to the level state of the first control signal.

[0097] In this step, the current flowing through the drive circuit 444 is acquired by the current acquisition module 441, and the rotor position of the motor 21 is acquired by the rotor position acquisition module 442. The current flowing through the drive circuit 444 is the current flowing through the coil of the motor 21. Then, based on the received yarn tension, the control unit 443 determines the reference current required to maintain the yarn tension and compares the reference current with the acquired current to determine whether the current of the motor 21 deviates from the reference current. Next, based on the comparison result and combined with the current rotor position, a first control signal is output to the drive circuit 444. The level of the first control signal is used to characterize the output current magnitude and commutation point of the motor 21. Finally, the drive circuit 444 adjusts the operating state of the motor 21 according to the level of the first control signal, so that its output torque matches the required yarn tension, thereby providing stable tension to the yarn. Because the yarn tension is stable, the surface of the produced fabric is smoother, improving product quality.

[0098] Furthermore, in this embodiment, the first control signal is a PWM pulse width modulation signal. When the current flowing through the motor 21 deviates from the reference current, the pulse width can be adjusted by adjusting the duty cycle of the PWM to obtain different sizes of output analog voltages. By changing the voltage connected to the motor 21, the current flowing through the motor 21 can be adjusted so that it is the same as the reference current.

[0099] It should be noted that the current acquisition module 441, rotor position acquisition module 442, and control unit 443 acquire current, acquire rotor position, and output a first control signal at a first preset frequency, respectively. Simultaneously, the control unit 443 receives a preset signal at a second preset frequency. The control unit 443 adjusts the PWM waveform based on the preset signal and the acquired actual value within each cycle, thereby adjusting the output torque of the motor 21. In some embodiments, the first preset frequency can be 1 millisecond, and the second preset frequency can be 50 microseconds; of course, other values ​​are also possible. Furthermore, the drive circuit 444 communicates with the main MCU via the SPI bus.

[0100] In some implementations, such as Figure 7 As shown, the control unit 443 includes an operational amplifier 443a and an analog-to-digital converter 443b;

[0101] The current acquisition module 441 includes a first resistor R424, a second resistor R422, a third resistor R425, a fourth resistor R426, a fifth resistor R420, and a sixth resistor R417.

[0102] One end of the first resistor R424 is connected to the drive circuit 444 and one end of the second resistor R422. The other end of the first resistor R424 is connected to one end of the third resistor R425. The other end of the second resistor R422 is connected to one end of the fifth resistor R420, one end of the sixth resistor R417, and the non-inverting input of the operational amplifier 443a. The other end of the third resistor R425 is connected to one end of the fourth resistor R426 and the inverting input of the operational amplifier 443a. The output of the operational amplifier 443a is connected to the other end of the fourth resistor R426 and the analog-to-digital converter 443b. The other end of the fifth resistor R420 is grounded. The other end of the sixth resistor R417 is connected to the power supply.

[0103] The current acquisition module 441 is used to acquire the current flowing through the drive circuit 444, including:

[0104] Obtain the voltage across the first resistor R424;

[0105] The acquired voltage is amplified by a preset factor using an operational amplifier 443a to obtain the amplified voltage;

[0106] The control unit 443 determines the current flowing through the drive circuit 444 based on the amplified voltage.

[0107] In practical applications, current is difficult to measure, and the most effective method is to convert current into voltage. In this embodiment, the first resistor R424 is a high-precision current sampling resistor with a resistance of 0.1Ω and an accuracy of 0.1%. A small resistor reduces energy loss, but the voltage across it is also relatively small. Therefore, it needs to be amplified by an operational amplifier 443a. Based on the principles of virtual short and virtual open circuits of the operational amplifier 443a, the second resistor R422, the third resistor R425, the fourth resistor R426, the fifth resistor R420, and the sixth resistor R417 are configured. The connection relationships between these resistors are as follows: Figure 7 As shown in the diagram, the voltage signal across the first resistor R424 can be amplified by 10 to 20 times using the above circuit. The operational amplifier 443a is preferably a differential amplifier, which has a high common-mode rejection ratio (CMRR) and can remove common noise signals, leaving only the voltage difference across the two ends, which is then amplified. This amplifier can accurately detect small voltage signals. Furthermore, the second resistor R422 and the third resistor R425 are 1KΩ, the fourth resistor R426 is 10KΩ, and the fifth resistor R420 and the sixth resistor R417 are 20KΩ. Of course, users can choose other resistor values ​​according to the amplification factor, and this application is not limited to this. Additionally, the end where the first resistor R424 and the third resistor R425 are connected can also be grounded.

[0108] In some implementations, such as Figure 7 As shown, the current acquisition module 441 also includes a seventh resistor R423 and a first capacitor C313; one end of the seventh resistor R423 is connected to the output terminal of the operational amplifier 443a and the other end of the fourth resistor R426 respectively, the other end of the seventh resistor R423 is connected to the analog-to-digital converter 443b and one end of the first capacitor C313 respectively, and the other end of the first capacitor C313 is grounded.

[0109] The control unit 443 determines the current flowing through the drive circuit 444 based on the amplified voltage, including:

[0110] The amplified voltage is low-pass filtered using the seventh resistor R423 and the first capacitor C313 to remove glitches and noise from the voltage waveform.

[0111] The noise-filtered voltage signal is converted from an analog signal to a digital signal using an analog-to-digital converter 443b.

[0112] The control unit 443 determines the current flowing through the drive circuit 444 based on the received digital signal.

[0113] In this embodiment, the seventh resistor R423 and the first capacitor C313 form an RC low-pass circuit, used to perform a low-pass filter on the output of the operational amplifier 443a, filtering out glitches and noise on the voltage waveform to obtain a stable current sampling value. In this figure, the seventh resistor R423 is 10KΩ and the first capacitor C313 is 1uF. Of course, users can also choose other resistance values, and this application is not limited to them. In addition, the analog-to-digital converter 443b can convert the acquired analog signal into a digital signal so that the control unit 443 can read and calculate it.

[0114] In some implementations, such as Figure 8 As shown, motor 21 is a three-phase motor, control unit 443 also includes analog comparator 443c, rotor position acquisition module 442 includes three parallel signal sampling circuits, each of which includes an eighth resistor R429, a ninth resistor R430 and a second capacitor C314.

[0115] One end of each eighth resistor R429 is connected to the motor 21, and the other end is connected to the analog comparator 443c. One end of the ninth resistor R430 is connected to the motor 21, and the other end of the ninth resistor R430 is connected to one end of the eighth resistor R429 and one end of the second capacitor C314. The other end of the eighth resistor R429 is connected to the analog comparator 443c, and the other end of the second capacitor C314 is grounded.

[0116] The rotor position of motor 21 is obtained using rotor position acquisition module 442, including:

[0117] The three signal values ​​of the Hall sensor are collected based on three eighth resistors R429;

[0118] An RC filter circuit consisting of the ninth resistor R430 and the second capacitor C314 is used to filter out noise in each signal value.

[0119] The analog comparator 443c determines the rotor position of the motor at the current moment based on the signal value after noise is filtered out.

[0120] In this embodiment, the signal value of the Hall sensor can be acquired by setting the eighth resistor R429. The eighth resistor R429 has a resistance of 4.7K and an accuracy of 1%. In addition, the ninth resistor R430 and the second capacitor C314 form an RC filter circuit to perform a low-pass filter on the Hall sensor signal on the motor 21 interface, filtering out some noise signals. By setting the above three-channel signal sampling circuit, the signal values ​​of the three Hall sensors can be obtained. The control unit 443 can determine the rotor position of the motor 21 at the current moment based on the signal values ​​of the three Hall sensors, and then determine the commutation point based on the rotor position. In addition, the resistance of the ninth resistor R430 is 1K and the accuracy is 1%, and the second capacitor C314 is 10nF. Of course, the user can also choose other resistance values, and this application is not limited to them.

[0121] In some implementations, the control unit 443 receives the yarn tension sent by the main MCU, and outputs a first control signal to the drive circuit 444 based on the yarn tension, the current acquired by the current acquisition module 441, and the rotor position acquired by the rotor position acquisition module 442, including:

[0122] The control unit 443 determines the reference current flowing through the motor 21 based on the received yarn tension;

[0123] Calculate the difference between the reference current and the current acquired by the current acquisition module 441;

[0124] The commutation point of motor 21 is determined based on the rotor position acquired by rotor position acquisition module 442;

[0125] Based on the calculated current difference and commutation point, the first control signal is output to the drive circuit 444.

[0126] In this step, the first control signal is a PWM (Pulse Width Modulation) signal. When the current of motor 21 deviates from the reference current, the pulse width can be adjusted by changing the duty cycle of the PWM to obtain different sizes of output analog voltages. By changing the voltage connected to motor 21, the current flowing through motor 21 is adjusted to make it the same as the reference current. In addition, the commutation time of motor 21 is determined based on the determined commutation point to ensure the stable operation of motor 21.

[0127] It should be noted that the control unit 443 can be a motor MCU with a main frequency of up to 96MHz. The MCU has a torque closed-loop control adjustment function, which can achieve a control tension accuracy of ±2g when the lever arm is fixed. It is especially suitable for applications with high knitting precision requirements.

[0128] In some implementations, such as Figure 9As shown, the driving circuit 444 includes a gate driver 444a and a three-way driving bridge circuit. Each driving bridge circuit includes two MOSFETs, a tenth resistor R412 and an eleventh resistor R414.

[0129] The input of the gate driver 444a is connected to the control unit 443. The output of the gate driver 444a is connected to one end of each tenth resistor R412 and one end of each eleventh resistor R414. The other end of each tenth resistor R412 and the other end of each eleventh resistor R414 are connected to the gate G of a MOSFET. The drain D of each MOSFET is connected to a coil port of the motor 21. The gate driver 444a is used to amplify the control signal output by the control unit 443.

[0130] The drive circuit 444 controls the output torque of the corresponding motor 21 according to the level state of the first control signal, including:

[0131] The first control signal is amplified to a preset value using gate driver 444a;

[0132] The on / off state and on / off time of each MOSFET are controlled based on the amplified signal, so as to control the output torque of the corresponding motor 21.

[0133] In this embodiment, the driving circuit 444 is a three-group, six-channel driving bridge structure. The gate driver 444a amplifies the first control signal, enhancing its driving capability to the gate G. After passing through the gate driver 444a, the amplified first control signal generates a PWM waveform with a driving capability of at least 1.0A. Furthermore, by setting the tenth resistor R412 (100Ω, 1% accuracy), the generated PWM waveform can be used to control the on / off state of the MOSFET at the HO terminal, thus controlling the turn-on and turn-off times of the upper transistor in the driving circuit 444. By setting the eleventh resistor R414 (100Ω, 1% accuracy), the generated PWM waveform can be used to control the on / off state of the MOSFET at the LO terminal, thus controlling the turn-on and turn-off times of the lower transistor in the driving circuit 444.

[0134] Furthermore, the MOSFETs at the HO and LO terminals cannot be turned on simultaneously. If they are turned on at the same time, the on-resistance of the MOSFETs is about 10 milliohms. The positive voltage terminal is directly grounded through the two MOSFETs, which will burn out the MOSFETs. Therefore, only one of the MOSFETs at the HO and LO terminals can be turned on at the same time.

[0135] It should be noted that the resistance values ​​of the tenth resistor R412 and the eleventh resistor R414 range from 20Ω to 120Ω. These resistors effectively suppress noise generated by the symbiotic inductance and capacitance formed by the drive circuit 444, and also suppress ringing during the PWM waveform's on and off states. Therefore, if the resistance is too small, the suppression effect is not significant; if the resistance is too large, it will cause signal lag and energy loss. Of course, the specific resistance values ​​of the tenth resistor R412 and the eleventh resistor R414 need to be determined based on the specific PWM waveform to ensure waveform stability.

[0136] In some implementations, such as Figure 9 As shown, each drive bridge circuit also includes a twelfth resistor R413 and a thirteenth resistor R415;

[0137] One end of the twelfth resistor R413 is connected to the tenth resistor R412, and the other end is connected to the source (S) of one of the MOSFETs. One end of the thirteenth resistor R415 is connected to the eleventh resistor R414, and the other end is connected to the source (S) of another MOSFET.

[0138] In this embodiment, the twelfth resistor R413 is connected to the gate (G) and source (S) of the MOSFET at the HO terminal, with a resistance of 10KΩ. This is because after the MOSFET is turned off, the residual voltage at the internal source (S) needs to be released through a suitable loop. The loop formed by the twelfth resistor R413, the gate (G), and the source (S) is used to release the residual voltage, thus protecting the MOSFET at the HO terminal. Similarly, the thirteenth resistor R415 protects the MOSFET at the LO terminal.

[0139] like Figure 9 As shown, by setting up three drive bridge circuits, a three-phase H-bridge circuit can be formed, which controls the three phases of the output motor 21 respectively, so that the motor 21 outputs a constant torque.

[0140] In addition, to ensure that the voltage between the gate G and source S of the HO terminal MOSFET is within the turn-on range, a bootstrap capacitor (not shown in the figure) can be provided on the drive circuit 444, and a Boost circuit (not shown in the figure) is provided in the control unit 443. Thus, under the action of the bootstrap capacitor, a boosted PWM waveform can be generated at the gate G of the HO terminal MOSFET, controlling the voltage between the gate and source S to be within the turn-on range.

[0141] In some embodiments, multiple filter circuits (not shown in the figure) are also included, one end of each filter circuit being connected to any input power supply in the yarn tension control system, and the other end being grounded. This effectively suppresses excess power in the event of power fluctuations, keeping the power supply below 24V and preventing damage to the MOSFET and the control unit 443 of the motor 21.

[0142] Finally, for step 104, tension is applied to the corresponding yarn using each motor 21.

[0143] In this step, each motor 21 is connected to a yarn. The output torque of the motor 21 is in the opposite direction to the tension of the yarn. The operation of the motor 21 drives the movement of the yarn to complete the corresponding weaving work.

[0144] In addition, in some embodiments, the industrial computer 1 is also used to send an alarm signal to each strapdown unit 2, each strapdown unit 2 is also used to send an alarm signal to the main MCU of each control board 4, and the main MCU is also used to output a second control signal to the control circuit 44 based on the received alarm signal.

[0145] The control circuit 44 is also used to control the motor 21 to turn off according to the level state of the second control signal.

[0146] In this embodiment, the second control signal is a PWM pulse width modulation signal, which can be used to turn the motor 21 on and off by adjusting its duty cycle. For example, when the continuous rotation angle of the motor 21 exceeds a preset angle (such as 270°), the control unit 443 controls the motor 21 to turn off by changing the waveform of the PWM, and feeds back to the upper-level control system through the SPI serial interface.

[0147] It should be noted that, in this document, relational terms such as "first" and "second" are used only 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 thereof 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 a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0148] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for controlling yarn tension, characterized in that, An application is made to a yarn tension control system, the system comprising an industrial computer and multiple strapdown units, the industrial computer being communicatively connected to each strapdown unit, each strapdown unit including at least one motor, and each motor connected to a yarn; the method comprising: The industrial control computer sends a preset yarn tension to each of the strapdown units; Each strapdown unit controls the output torque of its corresponding motor based on the received yarn tension. Each of the aforementioned motors provides tension to the corresponding yarn; Each strapdown unit includes multiple control boards connected in sequence. Each control board includes a second switch, a PHY, a main MCU, and multiple control circuits. The second switch is connected in series with the second switch of its adjacent control board. The PHY is connected to the second switch and the main MCU respectively. The main MCU is communicatively connected to each control circuit. Each control circuit is connected to a motor. The method of controlling the output torque of the corresponding motor of each strapdown unit based on the received yarn tension includes: Each of the control boards is connected in series using each of the second switches, so that the preset yarn tension is transmitted to each of the control boards respectively; For each of the control boards, the current main MCU uses the received yarn tension to control the working state of each corresponding control circuit, so as to control the output torque of the corresponding motor; Each of the control circuits includes: a current acquisition module, a rotor position acquisition module, a control unit, a drive circuit, and a motor; wherein, the input terminal of the current acquisition module is connected to the drive circuit, and the output terminal is connected to the control unit; the input terminal of the rotor position acquisition module is connected to the motor, and the output terminal is connected to the control unit; the control unit is connected to the drive circuit, and the output terminal of the drive circuit is connected to the motor. The method of using the current main MCU to control the working state of each corresponding control circuit based on the received yarn tension, so as to control the output torque of the corresponding motor, includes: For each of the aforementioned control circuits, the following is executed: The current flowing through the drive circuit is collected using the current acquisition module. The rotor position of the motor is obtained using the rotor position acquisition module; The control unit determines the reference current flowing through the motor based on the received yarn tension; Calculate the difference between the reference current and the current acquired by the current acquisition module; The commutation point of the motor is determined based on the rotor position acquired by the rotor position acquisition module; Based on the calculated current difference and commutation point, a first control signal is output to the drive circuit; The drive circuit controls the output torque of the corresponding motor according to the level state of the first control signal; the level state of the first control signal is used to characterize the output current and commutation point of the motor. The first control signal is a PWM pulse width modulation signal. When the current flowing through the motor deviates from the reference current, the pulse width is adjusted by adjusting the duty cycle of the PWM to obtain different sizes of output analog voltage. By changing the voltage connected to the motor, the current flowing through the motor is adjusted to make it the same as the reference current. The control unit includes an operational amplifier and an analog-to-digital converter. The current acquisition module includes a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, and a sixth resistor; One end of the first resistor is connected to the driving circuit and one end of the second resistor, respectively. The other end of the first resistor is connected to one end of the third resistor. The other end of the second resistor is connected to one end of the fifth resistor, one end of the sixth resistor, and the non-inverting input terminal of the operational amplifier, respectively. The other end of the third resistor is connected to one end of the fourth resistor and the inverting input terminal of the operational amplifier, respectively. The output terminal of the operational amplifier is connected to the other end of the fourth resistor and the analog-to-digital converter, respectively. The other end of the fifth resistor is grounded, and the other end of the sixth resistor is connected to the power supply. The resistance of the first resistor is 0.1Ω. The step of acquiring the current flowing through the drive circuit using the current acquisition module includes: Obtain the voltage across the first resistor; The acquired voltage is amplified by a preset factor using the operational amplifier to obtain the amplified voltage; The control unit uses the amplified voltage to determine the current flowing through the drive circuit.

2. The method according to claim 1, characterized in that, The yarn tension control system also includes a first switch, the input port of which is connected to the industrial computer via a bus of preset capacity, and the output port is connected to each of the strapdown units via an Ethernet bus. The step of sending a preset yarn tension to each strapdown unit using the industrial control computer includes: The industrial control computer is used to transmit the preset yarn tension to the first switch; The preset yarn tension is sent to the corresponding strapdown unit using the first switch.

3. The method according to claim 1, characterized in that, The current acquisition module further includes a seventh resistor and a first capacitor; one end of the seventh resistor is connected to the output terminal of the operational amplifier and the other end of the fourth resistor, the other end of the seventh resistor is connected to the analog-to-digital converter and one end of the first capacitor, and the other end of the first capacitor is grounded; The step of using the control unit to determine the current flowing through the drive circuit based on the amplified voltage includes: The amplified voltage is low-pass filtered using the seventh resistor and the first capacitor to remove glitches and noise from the voltage waveform. The analog-to-digital converter is used to convert the noise-filtered voltage signal from an analog signal into a digital signal. The control unit uses the received digital signal to determine the current flowing through the drive circuit.

4. The method according to claim 1, characterized in that, The motor is a three-phase motor, the control unit also includes an analog comparator, and the rotor position acquisition module includes three parallel signal sampling circuits, each of which includes an eighth resistor, a ninth resistor, and a second capacitor. One end of each of the eighth resistors is connected to the motor, and the other end is connected to the analog comparator. One end of the ninth resistor is connected to the motor, and the other end of the ninth resistor is connected to one end of the eighth resistor and one end of the second capacitor. The other end of the eighth resistor is connected to the analog comparator, and the other end of the second capacitor is grounded. The step of obtaining the rotor position of the motor using the rotor position acquisition module includes: The three signal values ​​of the Hall sensor are collected based on the three eighth resistors respectively; The RC filter circuit composed of the ninth resistor and the second capacitor is used to filter out noise in each signal value; The analog comparator determines the rotor position of the motor at the current moment based on the signal value after noise is filtered out.

5. The method according to claim 4, characterized in that, The driving circuit includes a gate driver and three driving bridge circuits, each of which includes two MOSFETs, a tenth resistor and an eleventh resistor. The gate driver's input is connected to the control unit, and the gate driver's output is connected to one end of each of the tenth resistors and one end of each of the eleventh resistors. The other end of each of the tenth resistors and the other end of each of the eleventh resistors are connected to the gate G of a MOS transistor. The drain D of each MOS transistor is connected to a coil port of the motor. The gate driver is used to amplify the control signal output by the control unit. The step of controlling the output torque of the corresponding motor using the drive circuit according to the level state of the first control signal includes: The first control signal is amplified to a preset value using the gate driver; The on / off state and on / off time of each MOS transistor are controlled based on the amplified signal to control the output torque of the corresponding motor.

6. The method according to claim 1, characterized in that, The industrial control computer is also used to send an alarm signal to each of the strapdown units, and each of the strapdown units is also used to send the alarm signal to the main MCU of each of the control boards. The main MCU is also used to output a second control signal to the control circuit based on the received alarm signal. The control circuit is also used to control the motor to turn off based on the level state of the second control signal.

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