The application of digital servo and motion contro

[senchuang] Application of digital servo and motion control technology in textile machinery

in recent years, with the enhancement of people's aesthetic awareness and the improvement of living standards, high-end yarn dyed products have become more and more popular. Not only real silk, but also chemical fiber, rayon, blended yarn and cotton yarn can also be woven with colored silk, which promotes the bobbin dyeing process to be widely used in the yarn dyed textile industry. Generally, the purchased green yarn needs to be wound into a "loose package" suitable for package dyeing for the next process before dyeing, so the demand for loose precision winders is increasing. The existing loose winder in China generally adopts the single spindle centralized transmission mode, which usually includes several movements such as winding, yarn guide and overfeed, and is completed by mechanical gear and cam mechanism. It is difficult to adjust the equipment for different winding processes of various yarns; The yarn guide mechanism adopts grooved barrel and rotating wing, which is easy to damage some high-grade yarns; At the same time, due to the mechanical transmission structure, the winding speed is not high. At present, this kind of loose winder abroad has completely adopted the full digital winding structure based on electronic gear and electronic cam, that is, single spindle independent transmission; The winding, traverse yarn guide, yarn overfeed and tension compensation are all controlled by separate motors. The motion relationship between the motors can be described through parameter settings, which can flexibly meet the needs of yarn winding process with various characteristics; The traverse yarn guide adopts the "yarn guide", which is commonly known as the "rabbit head", which has little damage to the yarn, and is especially suitable for the winding of high-grade yarn dyed yarn; In addition, because each motor has no direct transmission connection mechanically, supplemented by high-speed and precision motion control software algorithm, it can easily realize high-speed and precision cross winding. The winding speed is much higher than the mechanical loose winder, which greatly improves the winding efficiency. Beijing Hollysys Motor Technology Co., Ltd. has successfully developed the electrical control scheme of high-speed precision loose winder with independent intellectual property rights for the first time in China based on its years of accumulation of servo and motion control technology in accordance with the process characteristics of the precision loose winder through cooperation with the famous domestic textile machinery group. The whole scheme has self insulation, which is mostly used for non bearing walls in use. The thermal performance of self insulation walls is stable and is not affected by the construction quality; The construction operation is simple, avoiding the destructive effect of the second decoration on the internal insulation materials; It can solve the problem of wall thermal insulation of high-rise buildings; Through the design of material block structure, the problem of external wall leakage can be solved, and the performance price ratio is good, which greatly improves the automation level of domestic loose winders, and the main technical indicators have reached the level of similar foreign equipment. At present, the control scheme of China's economic slowdown system is introduced. Taking single spindle control as an example, the principle of the system control scheme is shown in Figure 1. The transverse motor shaft is connected with a steel wheel, which is fastened on the steel wire through the positive and negative rotation drive of the steel wheel, and the yarn guide moves left and right to realize the transverse layout movement of the yarn; The winding motor directly drives the bobbin to rotate to realize the winding movement of the yarn. After the above two movements of traverse and winding are combined, the yarn is rewound in the shape of a helix, avoiding the injury to the operator caused by misoperation to the greatest extent, and wound on the surface of the bobbin. Tension compensation motor and overfeed motor are mainly used to control the tension in the process of yarn winding. In this scheme, a specially designed ultra-small inertia servo motor is used for the traverse yarn guide motor, a specially designed and customized high-speed brushless DC motor is used for the winding and overfeed motor, and an ordinary stepping motor is used for the tension motor. The "single spindle control driver" in the figure is a special motor drive control system based on the all digital permanent magnet AC servo driver developed by Hollysys motor company, which is embedded with the high-speed electronic yarn guide motion control algorithm of the precision winder, the speed control of the winding brushless motor and the yarn tension control strategy. The whole system has simple structure and complete functions. By adjusting the internal memory parameters of "single spindle control driver" through keyboard or communication, it is convenient to set the geometric parameters of yarn winding forming (full barrel diameter, edging amplitude, etc.), winding linear speed, winding ratio, reciprocating motion length, differential amplitude, differential cycle, differential cam curve and other process parameters of hard edge trimming of yarn barrel. At the same time, it has RS232, RS485 The three communication interfaces of CAN bus can easily complete the multi spindle control and completely realize the flexible digital winding. The main technical parameters are listed as follows: precision winding and CNC layered winding can be realized; The control range of winding ratio is 2.000 ~ 12.000; The commutation acceleration of the transverse servo motor is as high as 8000r/s2, and the maximum reciprocating frequency is 800 times/minute, that is, 1600 commutations per minute; The traverse servo motor has the function of automatic zero change in the range, and there is no need to connect an external zero position sensor; Embedded with the control functions of winding, overfeed and tension compensation motors, it can be easily interfaced with the frequency converter, brushless DC motor driver and stepping motor driver to realize the control of winding motor, overfeed motor and tension compensation motor; With empty cylinder diameter calibration function; A variety of real-time parameters display, such as actual linear speed, bobbin diameter, reciprocating frequency, etc; A variety of fault protection measures, such as abnormal parameters, motor overspeed, drive out of tolerance, hardware failure, etc; Real time working parameters have power failure protection functions, such as winding length, winding diameter, etc; Introduction to transverse servo motor control in order to ensure that the bobbin has good dyeing performance, the yarn on the bobbin needs to be vertically crossed in space from the beginning of winding to any diameter point between the full bobbin, and they are not parallel to each other, so as to ensure that each layer of yarn does not overlap, that is to say, the winding ratio of the bobbin needs to be accurately controlled. The so-called winding ratio is the number of turns of the bobbin winding each time the traverse yarn guide hook reciprocates. There are three forms of cross winding: traditional slot drum winding (arbitrary winding), constant winding ratio precision winding and NC layered winding. This scheme mainly realizes two functions: constant winding ratio precision cross winding and NC layered winding. In order to realize precision cross winding, the "single spindle control driver" calculates the real-time speed by collecting the feedback encoder pulse signal of the winding motor in real time. According to the requirements of the precision winding process, the speed given command of the traverse servo motor is obtained with a unique numerical control algorithm, so as to ensure that the rotation speed of the traverse servo motor and the rotation speed of the winding motor maintain a certain relationship according to the definition of the winding ratio, Let the yarn be wound back and forth on the bobbin in the shape of a spatial spiral. By precisely controlling the winding ratio, the yarns that are wound back and forth cross each other without overlapping, that is to say, the precise winding of the bobbin is realized by skillfully using electronic gears and cams instead of mechanical gears and cams. In order to realize the high-speed performance of precision winding, the transverse servo motor needs to be able to reverse quickly when doing reciprocating motion, which requires the servo motor to have a high torque inertia ratio. Therefore, the transverse servo motor is uniquely optimized to ensure the rotor inertia of the motor