Constant-tension-control automatic yarn winding and unwinding yarn carrier and control method thereof

Abstract

The invention provides a constant tension control automatic yarn take-up and pay-off yarn carrier and a control method thereof, and belongs to the technical field of three-dimensional weaving, the constant tension control automatic yarn take-up and pay-off yarn carrier comprises a spring thread guide mechanism, a yarn guide rod and a yarn bobbin, the spring thread guide mechanism, the yarn guide rod and the yarn bobbin are all fixedly installed on a base, the yarn bobbin is driven by a motor, and the motor is connected with a battery and a single-chip microcomputer. When the yarn tension adjusting device works, the real-time tension value of the yarn is compared with the set tension value, then the corresponding actual output value is calculated through the PID algorithm, and the motor is driven to rotate so as to drive the yarn cylinder to rotate to collect and release the yarn, so that the yarn tension is adjusted. The device is simple in structure, external power supply is not needed during working, the influence of a yarn path on the yarn quality in the yarn winding and unwinding process is small, the tension can be rapidly and accurately adjusted, the tension is kept at a set value, extremely high universality is achieved, the knitting efficiency and the quality of knitted fabric can be improved, and development of the three-dimensional knitting technology and expansion of the application range are promoted.

Description

Technical Field

[0001] The invention belongs to the technical field of three-dimensional weaving, and in particular relates to a constant tension controlled autonomous yarn retracting and releasing yarn carrier and a control method thereof. Background Art

[0002] With the rapid development of aerospace, automobile, medical, construction and other fields, the requirements for material performance are constantly increasing, and traditional light metal materials can no longer meet the needs. Three-dimensional braided composite materials have become an important alternative material due to their excellent properties, such as strength, modulus, interlaminar strength and impact resistance.

[0003] Three-dimensional braiding technology is an extension of two-dimensional braiding technology. By increasing the number of yarns and yarn systems, more yarns are interwoven to create a multi-layer cross-linked braided structure. This structure significantly improves the mechanical properties of the material, especially the interlayer properties.

[0004] Domestic research on 3D braiding technology started late, with limited equipment types and low automation. It mainly relies on the four-step braiding process, with less research on the rotary braiding process, and lacks large-scale automated multi-layer cross-linked 3D rotary braiding machines.

[0005] The yarn carrier is a key component in a 3D braiding machine, responsible for carrying the yarn and moving it along a predetermined trajectory to achieve the interweaving and weaving of the yarn. Its performance directly affects the weaving efficiency and the quality of the braided fabric.

[0006] In the three-dimensional weaving process, especially when weaving preforms with variable cross-sections, the performance and flexibility of the yarn carrier are particularly important. However, the existing yarn carriers have deficiencies in driving mode, capacity, tension adjustment, etc., which are difficult to meet the needs of complex weaving processes.

[0007] Therefore, by studying and improving the yarn carrier of the braiding machine, its driving performance, capacity and tension adjustment stability can be improved, thereby improving the braiding efficiency and the quality of the braided fabric. It can promote the development of three-dimensional braiding technology and expand its application scope. It is of great significance to enhance my country's competitiveness in the fields of aerospace, automobiles, etc.

[0008] Authorization announcement number CN115287818 B discloses a yarn carrier and method with active yarn tension control function, including a frame, a winding mechanism, a control module, a tension sensor, an electric energy transmission system and a yarn guide rod; the winding mechanism, the control module and the tension sensor are arranged in the upper part of the frame from top to bottom, and the electric energy transmission system is arranged in the lower part of the frame and connected to the frame; the yarn drum is connected to the main shaft of the motor, the motor is fixed to the top of the motor support plate, and a plurality of upper connecting rods are arranged at the lower part of the motor support plate, the lower end of each upper connecting rod is connected to the upper surface of the frame, and the upper end of each upper connecting rod is fixed to the edge of the motor support plate; the single chip microcomputer is fixed to the middle part of the upper connecting rod; the tension sensor is connected to the frame, and the lower end of the yarn guide rod is connected to the upper surface of the frame; the tension sensor is connected to the single chip microcomputer in communication, and the signal output end of the single chip microcomputer is connected to the signal input end of the motor. This patent makes the braided structure more stable and uniform, and improves the automation degree and braiding efficiency of three-dimensional braiding.

[0009] However, the patent has the following problems: (1) The power transmission system is a sliding contact power transmission method. The ground grid is connected to AC power as required. The conductive wheel moves on the ground grid to collect AC power and transmits it to the rectifier. After rectification, it is converted into DC power, which avoids the problem of power cord entanglement during the operation of the yarn carrier caused by wired power supply. However, in fact, for large-scale three-dimensional knitting machines, the turntable needs to rotate continuously to form the winding of the yarn. Therefore, there is no continuous space for arranging the AC ground grid. At the same time, for automated equipment, laying AC power on the equipment is extremely dangerous, which seriously affects the safety of the equipment and operators. In addition, the three-dimensional knitting machine is mainly used to weave carbon fiber preforms. During the weaving process, carbon fiber is very easy to float in the air to form a conductive environment. Carbon fiber flocs falling on the power grid will also cause short circuits and fires. Therefore, the yarn carrier is actually not suitable for large-scale three-dimensional knitting automation equipment. (2) The yarn starts from the yarn bobbin, passes through the yarn guide rod to the tension sensor, and then returns to the yarn guide rod. It is transported from the top of the yarn guide rod for weaving. At this time, the yarn tension meets the rated yarn tension, and the motor rotates forward and the yarn bobbin rotates to release the yarn. However, during this process, the yarn is passed at a large angle, which will cause serious burrs on the yarn, seriously affecting the final weaving quality. At the same time, the installation method of the tension sensor and the position of the yarn guide rod will lead to uneven force, seriously affecting the structural stability of the yarn carrier and the stability of the yarn tension when it is working. In addition, the yarn is directly connected to the sensor. When the yarn tension fluctuates greatly, it is very easy to cause a large impact on the yarn carrier body and the yarn itself, affecting the yarn quality and tension stability. (3) The single-chip microcomputer receives the tension signal from the tension sensor in real time. When a displacement close to the direction of the braided fabric occurs, the yarn tension measured by the tension sensor is less than the rated yarn tension value, and a rewinding instruction is issued to the motor. The motor reverses and the yarn tube rotates in the opposite direction to collect the yarn. The yarn tension measured by the tension sensor meets the rated yarn tension value again. The single-chip microcomputer issues a release instruction to the motor, and the motor rotates forward and the yarn tube rotates to release the yarn. However, this control logic is actually unable to stabilize the yarn tension. The yarn tension fluctuates regularly but also has a certain degree of randomness (generally speaking, it changes periodically, and changes to a certain extent with the vibration of the equipment). Under this condition, the control of the yarn tension is unstable if only the measured value of the tension sensor is compared with the set value for forward and reverse rotation. It is very easy for the tension to be too large to start reverse rotation and too small to start forward rotation. The reciprocating adjustment cannot be stable. At the same time, the yarn cannot withstand such repeated yarn retraction and release, which directly damages the quality of the yarn itself and affects the weaving effect. (4) There is no effective feedback for the abnormal working status of the equipment such as yarn breakage and abnormal operation of the yarn carrier caused by accidents during the weaving process, and the operator cannot grasp the working status of the weaving machine and each yarn carrier in real time.

[0010] Authorization announcement number CN104562429B discloses a method and system for power transmission and tension compensation of a rotary yarn carrier, which includes a position detection device, a signal processing control circuit, a yarn feeding rotating device and a guide rail; wherein the position detection device can run along the guide rail; the position detection device, the signal processing control circuit and the yarn feeding rotating device are electrically connected in sequence; the guide rail is a guide rail with power transmission function, which is electrically connected to the signal processing control circuit and the yarn feeding rotating device respectively. This patent can actively and continuously control the tension of the yarn, and control the fluctuation range of the yarn by detecting the fluctuation trend of the yarn tension and using a feedforward method, so as to stabilize the tension on the braided yarn to the greatest extent, so that the winding degree of the surface of the braided fabric is more consistent.

[0011] However, the patent has the following problems: (1) The problem of power supply for the yarn carrier is consistent with that of patent CN 115287818 B. The sliding contact power transmission is prone to short circuit, which seriously affects the safety of the equipment and operators. (2) Through the three-dimensional weaving spindle extraction speed and weaving process, under the premise of ensuring a certain tension of the yarn, the yarn feeding amount under the condition of constant relative distance between the yarn carrier and the spindle is determined as the basic amount of the yarn feeding rotating device; when the weaving machine is not in working state, the relationship between the position change of the yarn carrier in one cycle and the change of the spindle distance is established, and the relationship between the position change and the yarn increment is obtained, and the relationship is input into the microcomputer processor; through the contact between the guide wheel and the guide rail, the height change of the guide rail is transmitted to the signal processing control circuit through the detection connecting rod and the side rod. The signal processing control circuit determines the position of the yarn feeding rotating device on the guide rail by detecting the displacement change of the side rod, and sends a corresponding control signal to the yarn feeding rotating device according to the position information; the yarn feeding rotating device outputs the corresponding yarn feeding amount under the control signal to ensure that the tension of the yarn can remain stable. However, the position of the yarn carrier is determined by the side rod to determine the displacement change and then output the corresponding control signal according to the pre-established periodic relationship. This method can theoretically achieve the corresponding control effect when the weaving process remains unchanged. In fact, due to the vibration of the equipment during the weaving process and the shaking caused by the movement of the yarn carrier, large tension fluctuations will occur. This fluctuation value cannot be calculated in advance. Therefore, when this factor is not considered, the yarn tension cannot be effectively controlled to remain stable during the weaving process based on the actual calculation of the yarn retraction and release cycle law. In addition, long-term operation will cause wear of the slide rail, and the measurement of the displacement signal is easily disturbed, which seriously affects the control output value. At the same time, if the weaving process is changed, the periodic change function needs to be recalculated, and rapid deployment of production cannot be achieved. It cannot adapt to the ever-changing production environment. (3) The large-angle yarn passing during the yarn retraction and release process has not been considered, which will cause burrs on the yarn and affect the weaving quality. At the same time, when the work is abnormal, it is impossible to provide timely and effective feedback to the equipment operator.

[0012] Application publication number CN116334834A discloses a yarn carrier with semi-active tension compensation function, including a tension compensation device, a reduction motor, and a travel switch; wherein the reduction motor is responsible for controlling the forward release and reverse retraction of the yarn bobbin, the travel switch is responsible for controlling the reversal of the reduction motor, the tension compensation device is responsible for stabilizing the small range fluctuation of the yarn tension and controlling the opening and closing of the travel switch, and the DC power required by the device is transmitted in a contact manner; and also includes a working method of using the above-mentioned yarn carrier. The patent has a simple structure, small size, and low cost. It adopts a mechanical control scheme with high reliability and easy operation. It can actively release the yarn and rewind the yarn of any length. The tension compensation device and the reduction motor work together to ensure the stability of the yarn tension during the weaving process. It adopts a contact power transmission scheme with a simple structure and avoids the problem of wire winding. It is suitable for large-scale three-dimensional weaving automation equipment.

[0013] However, the patent has the following problems: (1) It adopts a contact-type power transmission design, through which the conductive springs of the base contact with the conductive contacts on the angle wheel and the conversion device to power the yarn carrier. However, the contact-type power supply requires the installation of conductive slip rings on each turntable. The large number of them greatly reduces the reliability of the equipment. During long-term operation, it is very easy to cause poor contact and the yarn carrier cannot be effectively powered, resulting in the inability to adjust the yarn tension and the excessive tension breaking. At the same time, the turntable needs to be made of metal due to strength and wear resistance requirements. Under this condition, the power contact electrode installed on the turntable is prone to short circuit, and the carbon fiber floating in the air is also conductive, which seriously affects the safety of the equipment during operation. (2) A travel switch is used to control the commutation of the reduction motor, and the movement of the horizontal shaft extension of the tension compensation device is used to mechanically control the opening and closing of the travel switch. During the weaving process, the yarn tension has slight fluctuations. When the yarn tension increases, the compression of the spring increases, the drive block moves upward, and the yarn transportation distance becomes shorter; when the yarn tension decreases, the spring releases the compression, the drive block moves downward, and the yarn transportation distance becomes longer; the purpose of yarn tension compensation is achieved by changing the yarn transportation distance. When the yarn tension decreases significantly, the yarn tension can no longer be supplemented by increasing the yarn transportation distance. At this time, the horizontal axis touches the travel switch contact, the travel switch is in a closed state, the reduction motor rotates in the opposite direction, and the yarn tube changes from forward release to reverse winding of the yarn. As the yarn is rewound, the yarn tension increases. When the yarn tension reaches the weaving tension range again, the spring is compressed again, the drive block moves upward, the travel switch opens, the reduction motor resumes forward rotation, and the yarn tube continues to release the yarn to participate in weaving. However, this adjustment method is completely unable to achieve the expected function. First, it is impossible to ensure the consistency of the springs of each yarn carrier. The precision of the spring under this stroke is extremely low. The distance between several travel switches cannot effectively reflect the set tension value. At the same time, the installation of the travel switch will also produce errors, which further affects the adjustment of the tension. The tension value indicated by the travel switch itself has a large error that cannot be solved, and the overall control effect is extremely poor. At the same time, this control method will cause the motor to continuously rotate forward and reverse, that is, continuously retract and release the yarn, resulting in burrs on the yarn and even yarn breakage. The continuous forward and reverse rotation also seriously affects the life of the motor, resulting in the yarn carrier being unable to be used multiple times. There are thousands of yarn carriers on large-scale knitting machines. A large number of yarn carriers are continuously rotating forward and reverse at the same time, resulting in serious vibration and resonance, and are completely unusable, which seriously affects the normal use of the equipment. (3) There is no effective feedback for abnormal working conditions of the equipment such as yarn breakage and abnormal operation of the yarn carrier caused by accidents during the weaving process, and the operator cannot grasp the working status of the knitting machine and each yarn carrier in real time. Summary of the invention

[0014] The problem to be solved by the present invention is to provide a constant tension controlled autonomous yarn retracting and releasing yarn carrier and a control method thereof.

[0015] In order to solve the above technical problems, the technical solution adopted by the present invention is: a constant tension controlled autonomous yarn retracting and releasing yarn carrier, comprising a spring wire guide mechanism, a yarn guide rod and a yarn drum, wherein the spring wire guide mechanism, the yarn guide rod and the yarn drum are all installed and fixed on the base, the spring wire guide mechanism comprises a sensor, a spring limiting rod, a spring sleeve, a spring and a wire wheel, the upper end of the sensor is connected to the spring limiting rod, the spring limiting rod is sleeved with a spring, the upper end of the spring limiting rod is connected and fixed to the upper end of the spring, so that the upper end of the spring is always in the same position, the spring sleeve is sleeved on the outside of the spring, the bottom end of the spring sleeve is connected and fixed to the bottom end of the spring, and the spring sleeve is used to drive the spring to move The lower end of the spring moves upward to perform a compression action, and at the same time, the top of the spring sleeve is closed with a sleeve top cover, so that the spring is always kept compressed in the spring sleeve. The sleeve top cover is fastened to the spring sleeve. It can be seen that the upper part of the spring is limited in displacement by the spring limit rod, and the lower part is driven for compression by the spring sleeve; a wire wheel is installed above the sleeve top cover, and the yarn passes through the groove of the wire wheel. When passing through the line, the wire wheel 7 rolls and the yarn slides on it, reducing the impact on the yarn quality; a yarn guide rod is arranged on one side of the spring wire guide mechanism, and the yarn drum is located on the side of the yarn guide rod away from the spring wire guide mechanism; the yarn drum is driven by a motor, and the motor is respectively connected to a battery and a single-chip microcomputer.

[0016] Furthermore, a longitudinally penetrating upper ceramic eye is installed on the top of the yarn guide rod, and a transversely penetrating middle ceramic eye is installed on the yarn guide rod.

[0017] Furthermore, a yarn tube cover is provided at the upper end of the yarn tube, one end of the yarn tube cover is hinged to the top end of the yarn guide rod, and the other end of the yarn tube cover is connected to the top of the yarn tube through a metal spring and a bearing.

[0018] Furthermore, the top of the yarn drum is connected to the inner ring of the bearing through a rotating shaft, and a groove is provided on the extension shaft at the upper end of the rotating shaft, through which the metal spring on the yarn drum cover is clamped, and the metal spring uses its own elasticity to clamp the groove of the extension shaft of the yarn drum for positioning; the outer ring of the bearing is fixed in the slot of the yarn drum cover, and the inner ring of the bearing is fixed to the yarn drum. It can be seen that the yarn drum cover is hinged to the yarn guide rod, so that it can rotate at a large angle, which is convenient for disassembling the yarn drum. At the same time, the metal spring and bearing are installed inside the yarn drum cover. The metal spring is used to clamp the yarn drum to prevent the yarn drum from falling off during use, and the bearing makes the yarn drum rotate more smoothly, avoiding the difficulty of retracting and releasing the yarn due to friction.

[0019] Furthermore, the motor is a DC reduction motor with an encoder; the single-chip computer includes a power board and a control board, and the power board is connected to the control board; the power board is used to receive DC power input from the battery, and supply it to the MCU after passing through the step-down module. The power board is also provided with a voltage and current detection module for detecting the voltage and current of the battery; the control board is provided with an MCU, an AD acquisition module, a DC motor drive module and a wireless communication module. The MCU, i.e., a micro control unit, is the control core of the entire yarn carrier.

[0020] Furthermore, the dovetail groove on the base is connected to the turntable of the knitting machine, which is convenient for installation and disassembly. By pressing down the metal spring on the yarn tube cover, the yarn tube cover can be lifted up and the yarn tube can be removed from the output shaft of the motor; the battery is fixed to the base through a quick release port and buckles, and the battery can be removed by pressing all the buckles at the same time.

[0021] Furthermore, the yarn passes through the middle ceramic eye on the yarn guide rod on the yarn bobbin, bypasses the groove on the guide wheel on the sleeve top cover, and then passes through the upper ceramic eye on the yarn guide rod to the traction mechanism of the knitting machine. When the yarn is retracted and released, it passes through the groove on the guide wheel, causing the guide wheel to roll and partially slide, reducing the impact on the yarn quality.

[0022] The present invention also provides a control method for a yarn carrier with constant tension control and autonomous yarn retracting and releasing, comprising the following steps: S1, the MCU of the single-chip computer receives the tension data collected by the AD acquisition module and the signal of the current motor output shaft position output by the motor encoder in real time, and performs filtering processing; S2. When the yarn is pulled by the traction mechanism, the yarn is pulled outward and the yarn tension increases. The real-time tension value is compared with the set tension value, and then the corresponding actual output value is calculated through the PID algorithm. The output is output to the DC motor drive module to drive the motor to rotate and then drive the yarn tube to rotate to retract and release the yarn to adjust the yarn tension.

[0023] Furthermore, the PID algorithm is as follows: the AD acquisition module acquires the current real-time tension value, compares it with the set tension value, and calculates the current deviation, cumulative deviation, and the difference between the current and previous deviations, which are P, I, and D respectively. This is the first-level PID, and the initial motor PWM control value is not output, but only used as the input of the second-level PID; at the same time, the data of the current real-time position of the motor output shaft is integrated and calculated through the second-level PID to generate a new PWM control value, which is the final actual output value. The tension is adjusted to the set tension value while the motor speed is reduced to zero, so that the overall control curve is smoother and more accurate, and the cascade PID algorithm is realized.

[0024] Furthermore, the MCU sends data (current working status of the yarn carrier, i.e. real-time tension value, tension setting value, current battery power, current yarn storage amount) to the host computer every ten seconds through the wireless communication module, and the host computer can adjust the production at any time according to the overall operation status.

[0025] Due to the adoption of the above technical solution, the present invention has the following beneficial effects: (1) The battery of the present invention adopts a quick-release design, so that the yarn carrier does not need to rely on external power supply when working, which is conducive to the simplification of the overall equipment manufacturing of large-scale knitting machines, effectively reducing the manufacturing difficulty of the equipment, making the production deployment of the equipment more rapid, and suitable for quickly adjusting the specifications and processes of the equipment. At the same time, the yarn carrier does not need external power supply, which can reduce the difficulty of maintenance and make the maintenance of the knitting machine easier. When the yarn carrier fails, it is easier to troubleshoot the problem and the yarn carrier can be directly replaced.

[0026] (2) The yarn of the present invention passes through the middle ceramic eye on the yarn guide rod, bypasses the groove on the wire pulley on the top cover of the sleeve, and then passes upward through the upper ceramic eye on the yarn guide rod to the traction mechanism of the braiding machine. When the yarn is winding and releasing the yarn, it passes through the groove on the wire pulley, and the wire pulley produces rolling and partial sliding. The effect of rolling on the yarn quality is almost negligible. The slight sliding also minimizes the effect on the yarn due to the use of ceramic materials. At the same time, the lower spring also protects the yarn. When the yarn tension increases sharply, the spring acts as a buffer to prevent the yarn from breaking under excessive tension mutations. When the yarn tension decreases sharply, the spring plays a role of passively compensating for part of the tension, thereby minimizing the effect of the yarn path on the yarn quality during the process of winding and releasing the yarn.

[0027] (3) The present invention controls the rotation of the motor through a cascade PID algorithm to achieve the effect of retracting and releasing the yarn. The output torque of the motor is not fixed. It is necessary to obtain the PWM control value of the motor based on the combined effect of the yarn storage amount, the actual yarn tension value, and the battery voltage, and to correct the actual motor output PWM value to make the adjustment curve smoother, so as to achieve fast and accurate tension adjustment and maintain the tension at the set value.

[0028] (4) During the operation of the present invention, data (current working status of the yarn carrier, i.e. real-time tension value, tension setting value, current battery power, current yarn storage amount) is sent to the upper computer, i.e. the equipment industrial computer, at regular intervals, so that the operator can grasp the operating status of the equipment at any time. When an abnormal phenomenon occurs during the operation of the equipment, the operator is warned in time, so that the operator can quickly locate the cause of the fault and make corrections in time, which can greatly increase the production efficiency of the enterprise. At the same time, the tension setting value can be changed remotely as needed to realize variable tension weaving during the weaving process, which greatly enriches the weaving process and provides more production possibilities.

[0029] (5) The yarn carrier of the present invention is produced and assembled in a modular manner, and can be produced quickly and in large quantities. When the yarn carrier works abnormally, the faulty yarn carrier can be accurately located and replaced. In terms of economic benefits, the faulty module of the faulty yarn carrier can be quickly replaced for repair, thereby reducing production costs. The present invention has a simple structure, is easy to manufacture, and is convenient to repair. It can meet the current production requirements of rapid deployment and rapid production, and has no strict requirements on the shape, size, and weaving process of the weaving machine. It can be used on most current weaving machines without making major modifications to the weaving machine, and has extremely strong versatility. It can improve weaving efficiency and the quality of woven fabrics, and promote the development of three-dimensional weaving technology and the expansion of its application scope. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The present invention will be described in detail below with reference to the accompanying drawings and in combination with examples, and the advantages and implementation methods of the present invention will become more obvious. The contents shown in the accompanying drawings are only used to explain the present invention and do not constitute any limitation to the present invention in any sense. In the accompanying drawings: Figure 1 It is a structural schematic diagram of the present invention.

[0031] Figure 2 It is a schematic diagram of the three-dimensional structure of the present invention.

[0032] Figure 3 It is a schematic diagram of the internal structure of the yarn tube cover plate of the present invention.

[0033] Figure 4 It is a structural schematic diagram of the base of the present invention.

[0034] Figure 5 It is a structural schematic diagram of the present invention from another angle.

[0035] Figure 6 It is a structural schematic diagram of the spring wire mechanism of the present invention.

[0036] Figure 7 It is a module schematic diagram of the single chip microcomputer of the present invention.

[0037] In the figure: 1. Sensor; 2. Spring limit rod; 3. Spring sleeve; 4. Spring; 5. Pin; 6. Sleeve top cover; 7. Wire guide; 8. Yarn guide rod; 9. Middle ceramic eye; 10. Upper ceramic eye; 11. Yarn drum cover; 12. Yarn drum; 13. Motor; 14. Single chip microcomputer; 15. Battery; 16. Base; 17. Metal spring; 18. Bearing; 19. Tension sensor M3 threaded hole; 20. Yarn guide rod M3 threaded hole; 21. Micro USB hole; 22, motor M3 threaded hole; 23, M2 threaded column; 24, arc groove; 25, dovetail groove; 26, limit through hole; 27, yarn guide rod mounting groove; 28, boss; 141, power board; 142, control board; 1411, step-down module; 1412, voltage and current detection module; 1421, MCU; 1422, AD acquisition module; 1423, DC motor drive module; 1424, wireless communication module. DETAILED DESCRIPTION

[0038] like Figures 1 to 6 As shown, the present invention is a constant tension controlled autonomous yarn retracting and releasing yarn carrier, comprising a spring wire mechanism, a yarn guide rod 8 and a yarn drum 12, wherein the spring wire mechanism, the yarn guide rod 8 and the yarn drum 12 are all mounted and fixed on a base 16.

[0039] The spring wire mechanism includes a sensor 1, a spring limit rod, a spring sleeve 3, a spring 4 and a wire wheel 7. The sensor 1 is connected to the lower base 16 by an M3 thread, and the spring washer and the M3 thread cooperate with each other to prevent loosening. The upper end of the sensor 1 is connected to the threaded end of the spring limit rod 2 by an M3 thread, and the connection is fastened with a spring washer and a nut. The sensor 1 adopts an S-type high-precision miniature tension and compression integrated sensor (size is 19cm-16cm-6cm). A spring 4 is sleeved on the spring limit rod 2, and the upper end of the spring limit rod is connected and fixed to the upper end of the spring 4, so that the upper end of the spring 4 is always in the same position. The spring sleeve 3 is sleeved on the outside of the spring 4. The bottom end of the spring sleeve 3 is connected and fixed to the bottom end of the spring 4. The spring sleeve 3 is used to drive the lower end of the spring 4 to move upward for compression. At the same time, the top of the spring sleeve 3 is closed with a sleeve cover 6, so that the spring 4 is always kept compressed in the spring sleeve 3. The sleeve cover 6 is fastened to the spring sleeve 3 through the pin 5. It can be seen that the displacement of the spring 4 is limited by the spring limit rod 2 above, and the compression is driven by the spring sleeve 3 below. A wire wheel 7 (ceramic groove bearing) is installed above the sleeve cover 6. The wire wheel 7 is connected and fixed to the sleeve cover 6 through an M3 screw nut. The yarn passes through the groove of the wire wheel 7. When passing through the line, the wire wheel 7 rolls and the yarn slides on it, reducing the impact on the yarn quality.

[0040] A yarn guide rod 8 is provided on one side of the spring wire mechanism, and the bottom of the yarn guide rod 8 is tightly connected to the base 16 of the yarn carrier to ensure its verticality; a longitudinally penetrating upper ceramic eye 10 (size 6.8cm-8cm-4cm) is installed on the top of the yarn guide rod 8, and a transversely penetrating middle ceramic eye 9 (size 9.5cm-8.6cm-4.6cm) is installed on the yarn guide rod 8.

[0041] The yarn drum 12 is located on the side of the yarn guide rod 8 away from the spring wire mechanism. A yarn drum cover 11 is provided on the upper end of the yarn drum 12. One end of the yarn drum cover 11 is hinged to the top of the yarn guide rod 8, and the other end of the yarn drum cover 11 is connected to the top of the yarn drum 12 through a metal spring 17 and a bearing 18. Specifically, the top of the yarn drum 12 is connected to the inner ring of the bearing 18 through a rotating shaft, and a groove is provided on the extension shaft at the upper end of the rotating shaft. The metal spring 17 on the yarn drum cover 11 is clamped through the groove. The metal spring 17 uses its own elasticity to clamp the groove of the extension shaft of the yarn drum 12 for limiting. The bearing has an outer diameter of 10 cm, an inner diameter of 4 cm, and a thickness of 4 cm. The outer ring of the bearing 18 is fixed in the slot of the yarn drum cover 11, and the inner ring of the bearing 18 is fixed to the yarn drum 12. It can be seen that the yarn tube cover plate 11 is hinged to the yarn guide rod 8, so that it can rotate at a large angle, which is convenient for removing the yarn tube 12. At the same time, the yarn tube cover plate 11 is equipped with a metal spring 17 and a bearing 18. The metal spring 17 is used to clamp the yarn tube 12 to prevent the yarn tube 12 from falling off during use. The bearing 18 makes the yarn tube 12 rotate more smoothly to avoid difficulties in retracting and releasing the yarn due to friction.

[0042] The bottom of the yarn tube 12 is driven by a motor 13, which is a DC reduction motor with an encoder. The motor output shaft has a diameter of 4 cm. The upper surface of the motor 13 is directly connected to the yarn tube 12 using two M3 screws, and the screws are evenly distributed on a circle with a diameter of 17 cm.

[0043] like Figure 7As shown, a single-chip microcomputer 14 is arranged adjacent to the motor 13, and the single-chip microcomputer 14 includes a power board 141 and a control board 142, and the power board 141 and the control board 142 are connected by a pin header with a spacing of 1.27. A micro USB hole 21 is provided on the base 16 above the single-chip microcomputer 14 for downloading and debugging programs, and can be sealed by a rubber plug when not in use. The power board 141 is responsible for receiving the 12V direct current input by the battery 15, and the 12V is reduced to 3.3V for use by the MCU 1421 through the step-down module 1411. The power board 141 is also provided with a voltage and current detection module 1412 for detecting the voltage and current of the battery 15; the control board 142 is provided with an MCU 1421, an AD acquisition module 1422, a DC motor drive module 1423 and a wireless communication module 1424. The MCU 1421 is a micro control unit, which is the control core of the entire yarn carrier. In addition, there are three LED lights, two green and one red, on the control panel. When the yarn carrier is operating normally, the green light flashes and the power indicator light is long green. When the battery 15 is too low, the other green indicators are turned off and the red light is long red for warning.

[0044] A battery 15 is installed below the motor 13. The battery 15 is a 12V lithium battery, which is composed of three 805034 3.7V lithium batteries connected in series, with a total power of 1800mah. The interface is a gh1.25 lock interface to prevent the yarn carrier from being vibrated and loosening during operation.

[0045] The base 16 is used to fix the components of the yarn carrier. The base 16 has a dovetail groove 25 at the bottom to fix it on the turntable of the knitting machine, which is convenient for installation and disassembly. At the same time, there is a limit through hole 26 that cooperates with the dovetail groove 25 to fix the yarn carrier on the turntable of the knitting machine. The base 16 has a total of 8 threaded holes, including one M3 threaded hole 19 for the tension sensor 1 to be installed, and the installation surface is sunken by 1mm; one M3 threaded hole 20 for the yarn guide rod 8 to be installed, two M3 threaded holes 22 for the motor 13 to be installed (evenly distributed on a circle with a diameter of 17, and the direction is parallel to the yarn guide rod 8), and four M2 threaded holes 23 for the single-chip microcomputer 14 to be installed. Four M2 screws connect the shell through the through holes on the single-chip microcomputer 14 and the threaded holes on the base 16 to fix the shell, and the shell seals the single-chip microcomputer 14 and other components inside. The battery 15 is designed to be quickly released and fixed to the base 16 with multiple clips, and the contacts on the base 16 are in contact with the battery 15 for power supply. The side wall of the base 16 is provided with four M2 threaded columns 23 for mounting and fixing the power board, control board, and housing of the single-chip microcomputer 14, and there is space below for placing extra wires. An arc groove 24 is provided on the base 16 below the motor 13 to facilitate the installation of the motor 13 from the side without interference from the base 16. A yarn guide rod mounting groove 27 is provided on the base 16 at the bottom of the yarn guide rod 8, and the yarn guide rod mounting groove 27 is sunken 1mm for limiting the position of the yarn guide rod 8; two 2mm bosses 28 are provided on the base 16 on the side of the yarn guide rod 8 for limiting the position of the yarn guide rod 8.

[0046] The yarn tube cover plate 11, the metal spring sheet 17 and the bearing 18 together limit the position of the yarn tube 12 and ensure that the axis of the yarn tube 12 is vertical.

[0047] The spring limiting rod 2, spring sleeve 3, spring 4, pin 5, sleeve top cover 6 and guide wheel 7 of the present invention together constitute a yarn tension passive compensation system.

[0048] When in use, the yarn carrier is connected to the turntable of the braiding machine through the dovetail groove 25 on the base 16, which is convenient for installation and removal. By pressing down the metal spring 17 on the yarn tube cover 11, the yarn tube cover 11 can be lifted up, and the yarn tube 12 can be removed from the output shaft of the motor 13. The battery 15 is fixed to the base 16 through the quick release port and the buckle, and the battery 15 can be removed by pressing all the buckles at the same time; the yarn on the yarn tube 12 passes through the middle ceramic eye 9 on the yarn guide rod 8, bypasses the groove on the wire guide wheel 7 on the sleeve top cover 6, and then passes upward through the upper ceramic eye 10 on the yarn guide rod 8 to the traction mechanism of the braiding machine. When the yarn is retracted and released, it passes through the groove on the wire guide wheel 7, and the wire guide wheel 7 rolls and partially slides, which reduces the impact on the yarn quality.

[0049] The present invention also provides a control method for a yarn carrier with constant tension control and autonomous yarn retracting and releasing, comprising the following steps: S1, the MCU1421 of the single chip computer 14 receives the tension data collected by the AD acquisition module 1422 and the signal of the current motor output shaft position output by the encoder of the motor 13 in real time, and performs filtering processing on it; The filtering process includes hardware filtering circuit processing and software filtering program processing in the MCU1421 program to avoid external interference.

[0050] S2. When the yarn of the yarn carrier is pulled by the traction mechanism, the yarn is pulled outward and the yarn tension increases. At the same time, the yarn bypasses the groove on the wire wheel 7, compressing the spring 4 and compressing the spring 4. The spring 4 can play a buffering role to avoid the tension sensor 1 and the yarn itself from being impacted when the yarn tension suddenly changes; the real-time tension value is compared with the set tension value, and then the corresponding output value is calculated by the PID algorithm, and output to the DC motor drive module 1423 to drive the motor 13 to rotate and then drive the yarn tube 12 to rotate to reel in and release the yarn to adjust the yarn tension.

[0051] Among them, the PID algorithm is: the AD acquisition module 1422 collects the current real-time tension value, compares it with the set target tension value, and calculates the current deviation, cumulative deviation, and the difference between the current and previous deviations, which are P, I, and D respectively. This is the first-level PID. The initial motor PWM control value is not output, but only used as the input of the second-level PID. At the same time, when the motor 13 is rotating, the encoder on the motor 13 will output the current position of the output shaft of the motor 13 in real time, and feed it back to the MCU1421. The second-level PID is integrated and calculated to generate a new PWM control value. The new PWM control value is the final actual output value, so that the tension is adjusted to the set tension value while the speed of the motor 13 is reduced to zero, so that the overall control curve is smoother and more accurate, that is, the control algorithm is a cascade PID algorithm.

[0052] Specifically, when the real-time tension value of the yarn is greater than the set tension value, in MCU1421, the set tension value minus the real-time tension value is used to obtain the current deviation value, which is multiplied by a certain value (currently 2.2), which is the proportional term; the deviation value is continuously accumulated to obtain a cumulative value, which is multiplied by a certain value (currently 0.045), which is the integral term, and an upper limit is set for accumulation to avoid an excessively large integral area. When the deviation is a negative deviation, the integral area is exited too slowly, which affects the tension regulation. The integral term is used to eliminate the steady-state error of the system; the difference between the current deviation value and the previous deviation value is calculated, and it is multiplied by a certain value (currently 0.02), which is the differential term, which improves the system's ability to respond to future changes, suppresses the slope of the control curve, and makes the control smoother; At the same time, the encoder of the motor 13 outputs the current position of the motor output shaft in real time. According to this position, the yarn storage amount of the current yarn tube 12 can be calculated (the diameter of the yarn tube 12 in the full yarn state is known, and the accumulated yarn release amount can be obtained by accumulating the data sent back by the encoder, and then the current yarn storage amount can be known). The change of the yarn storage amount causes the distance of the yarn on the yarn tube 12 relative to the axis to change, thereby changing the output torque of the motor 13.

[0053] The output value of the motor 13 is corrected in real time according to the change of the yarn storage amount, that is, the output torque of the motor 13 is corrected to ensure that the yarn tension is quickly and stably controlled at the set value. At this time, the PWM value of the motor 13 output is a negative value, that is, the motor 13 reverses to drive the yarn tube 12 to release the yarn, so that the yarn tension value is reduced to the set value.

[0054] When the real-time tension value is less than the set tension value, the yarn is relaxed relative to the previous state, which is reflected in the yarn lengthening, the compression distance of the spring 4 is reduced, and the pressure on the yarn forms a new force balance state, passively compensating the yarn tension. At the same time, the control algorithm in MCU1421 is consistent with the yarn tension value being greater than the set tension value. In this case, the output PWM value of the motor 13 is positive, that is, the motor 13 rotates forward to drive the yarn tube 12 to collect the yarn, so that the yarn tension value increases to the set value.

[0055] The real-time tension value fluctuates above and below the set tension value and performs PID control. The current set control accuracy is plus or minus 0.5N, that is, the motor does not rotate within this range and PID control is not performed.

[0056] Among them, MCU1421 records the change value of yarn tension in real time and saves it in the internal memory. It can analyze these data and predict future tension changes, and make further corrections to the AD acquisition value and PID output control value to make the control curve smoother and more accurate.

[0057] Among them, MCU1421 sends data (current working status of the yarn carrier, i.e. real-time tension value, tension setting value, current battery power, current yarn storage amount) to the host computer every ten seconds through the wireless communication module 1424. The host computer can thus know the overall operation status of the knitting machine so as to adjust the production at any time.

[0058] In addition, the MCU 1421 can adopt a power saving mode and enter the power saving mode when the knitting machine is not running to save power.

[0059] The embodiments of the present invention are described in detail above, but the contents are only preferred embodiments of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the present invention.

Claims

1. A constant tension controlled autonomous yarn retracting and releasing yarn carrier, characterized in that: It comprises a spring wire mechanism, a yarn guide rod and a yarn drum, wherein the spring wire mechanism, the yarn guide rod and the yarn drum are all installed and fixed on a base, the spring wire mechanism comprises a sensor, a spring limiting rod, a spring sleeve, a spring and a wire pulley, the upper end of the sensor is connected with the spring limiting rod, the spring limiting rod is sleeved with a spring, the upper end of the spring limiting rod is connected and fixed with the upper end of the spring, the spring sleeve is sleeved on the outside of the spring, the bottom end of the spring sleeve is connected and fixed with the bottom end of the spring, the top of the spring sleeve is closed by a sleeve top cover, a wire pulley is installed above the sleeve top cover, a yarn guide rod is arranged on one side of the spring wire mechanism, the yarn drum is located on the side of the yarn guide rod away from the spring wire mechanism; the yarn drum is driven by a motor, and the motor is respectively connected with a battery and a single-chip microcomputer.

2. The constant tension controlled autonomous yarn retracting and releasing yarn carrier according to claim 1, characterized in that: The top of the yarn guide rod is provided with an upper ceramic eye which penetrates longitudinally, and the yarn guide rod is provided with a middle ceramic eye which penetrates transversely.

3. The constant tension controlled autonomous yarn retracting and releasing yarn carrier according to claim 1, characterized in that: A yarn tube cover is arranged at the upper end of the yarn tube, one end of the yarn tube cover is hinged to the top end of the yarn guide rod, and the other end of the yarn tube cover is connected to the top of the yarn tube through a metal spring and a bearing.

4. The constant tension controlled autonomous yarn retracting and releasing yarn carrier according to claim 3, characterized in that: The top of the yarn drum is connected to the inner ring of the bearing through a rotating shaft. A groove is provided on the extension shaft at the upper end of the rotating shaft, and the metal spring on the yarn drum cover is clamped by the groove; the outer ring of the bearing is installed in the yarn drum cover.

5. The constant tension controlled autonomous yarn retracting and releasing yarn carrier according to claim 1, characterized in that: The motor is a DC reduction motor with an encoder; the single-chip computer includes a power board and a control board, and the power board is connected to the control board; the power board is used to receive DC power input from the battery, and supplies it to the MCU after passing through the step-down module. The power board is also provided with a voltage and current detection module for detecting the voltage and current of the battery; the control board is provided with an MCU, an AD acquisition module, a DC motor drive module and a wireless communication module.

6. The constant tension controlled autonomous yarn retracting and releasing yarn carrier according to claim 1, characterized in that: The dovetail groove on the base is connected to the turntable of the knitting machine; the battery is fixed on the base through a quick release port and a buckle.

7. The constant tension controlled autonomous yarn retracting and releasing yarn carrier according to claim 2, characterized in that: The yarn on the yarn bobbin passes through the middle ceramic eye on the yarn guide rod, bypasses the groove on the guide wheel on the sleeve top cover, and then passes through the upper ceramic eye on the yarn guide rod to the traction mechanism of the knitting machine.

8. A control method for a constant tension controlled autonomous yarn retracting and releasing yarn carrier, used to implement the constant tension controlled autonomous yarn retracting and releasing yarn carrier as claimed in any one of claims 1 to 7, characterized in that: The following steps are involved: S1, the MCU of the single-chip computer receives the tension data collected by the AD acquisition module and the signal of the current motor output shaft position output by the motor encoder in real time, and performs filtering processing; S2. When the yarn is pulled by the traction mechanism, the yarn is pulled outward, and the real-time tension value is compared with the set tension value. The corresponding actual output value is calculated through the PID algorithm and output to the DC motor drive module of the microcontroller to drive the motor to rotate and then drive the yarn tube to rotate to retract and release the yarn to adjust the yarn tension.

9. The control method of the constant tension controlled autonomous yarn retracting and releasing yarn carrier according to claim 8, characterized in that: The PID algorithm is as follows: the AD acquisition module acquires the current real-time tension value of the yarn, compares it with the set tension value, and calculates the current deviation, the cumulative deviation, and the difference between the current deviation and the previous deviation, which are P, I, and D respectively. This is the first-level PID. The initial motor PWM control value is not output, but only used as the input of the second-level PID. The data of the real-time position of the current motor output shaft is integrated and calculated through the second-level PID to generate a new PWM control value, which is the final actual output value.

10. The control method of the yarn carrier with constant tension control and autonomous yarn retracting and releasing according to claim 8, characterized in that: The MCU sends data to the host computer every ten seconds through the wireless communication module.

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