Winding Productivity and Tension Control System Operation Process
In actual production, if the center winding method is used to wind the roll, the diameter of the winding shaft is constantly changing.
Constantly changing winding diameter causes changes in angular velocity, which causes fluctuations in material tension: if the tension is too small, the material will be loosened and wrinkled when winding, and lateral deviation; if the tension is too large, it will lead to excessive stretching of the material, which will result in longitudinal tension lines and even longitudinal bulge.
In the process of winding to ensure the production efficiency and quality of winding, tension control system is particularly critical.
Tension control mode generally has two modes: open-loop and closed-loop control, of which the open-loop control mode has no tension check and feedback link.
The design and structure are relatively simple, but the control measurement and stability are poor.
Closed-loop control mode generally has a roll diameter check assembly and tension feedback link, the randomness of control is very strong, with high control accuracy and response speed, but the control design of the system is more troublesome and more components, the application in small equipment is somewhat limited.
Tension control is an extremely important part of the production process, and good tension control can ensure product quality and improve production efficiency.
This paper introduces the control principle of tension-controlled variable frequency winding.
This technology can ensure that the whole process of winding is stable, avoiding the phenomenon of too much tension in small rolls and too little tension in large rolls.
Based on the established mathematical model, the article introduces the principle of variable frequency winding, data processing according to a certain control strategy, and real-time adjustment of the control signal.
The data is processed according to a certain control strategy and the control signal is adjusted in real time. The winding diameter is calculated by PLC and the output frequency of the inverter is changed to control the motor.
For winding, with the gradual increase of winding diameter, the value of torque increases, and the output speed of inverter will decrease, which is in line with the basic principle of winding, and the synchronous tension is also under control.
The system realizes the process quantification of winding tension and completes the automatic tracking transformation of torque and speed.
1、Control system working principle and composition
In this paper, we choose the open-loop tension control system based on servo system and plc system, which is applied to the winding of 0.1mm grade material, and the quality of winding is equal to the quality of closed-loop control.
The servo control system is selected for this design based on its torque control mode which has the feature of simple control in rewinding.
In the torque mode, there is no need to control the speed of winding, only a speed limit value can be given to make the angular speed of the winding axis float automatically according to the size of the torque, and achieve constant line speed winding.
The inside torque checking performance of the synchronous servo controller can check the output current, thus realizing the high amount of torque control. The parameters of the system such as torque, speed command and radius of winding are calculated inside the plc system, which makes the system further simplified.
The system uses PLC as the controller, which mainly contains: host, switching input/output module, analog input/output module, stepper/servo motor control module and LCD color LCD touch screen and other components.
Switching quantity (including high-speed counting) input/output module: it mainly realizes the performance of the input of the control button, the zero-position check of the contraction rod, the counting of the photoelectric encoder and the control and status indication of the switching quantity.
Analog input module: Used for tension check, during winding process, the pressure signal of tension is transformed into electric signal by sensor and sent to PLC analog input module through tension transmitter for tension control and display.
Analog output module: through the tension check and the given tension through the PLC‘s PID operation to produce the current control amount, through the analog output module to achieve the excitation current control of the magnetic powder brake, to ensure the constant tension; speed control of the inverter, to achieve the speed control of the winding process, automatic speed reduction and positioning and other control performance.
Stepper motor control module: It is used for the control of stepper motor. According to the set winding diameter through the stepper motor to adjust the place of deflection rod. According to the thickness of the coil given by the stepper motor to control the winding process each time the winding diameter of the fine-tuning amount.
LCD touch screen: as the man-machine control interface, mainly to achieve the system control parameters input, the system work process, real-time monitoring of the work status, the display of control parameters and the system control performance.
2、Servo system design
Mitsubishi mr-j2s servo system has a local control mode, speed control mode, torque control mode three control methods, the design system to choose the torque control mode.
Which speed, torque command is set on the touch screen, and then transmitted to the plc, after the calculation of the plc through a1s68dav form 0 ~ 10v analog signal, transmitted to the servo system.
The servo system accepts the signal and then converts it into the motor speed and torque control signal through the inside unit, thus controlling the motor operation.
In the servo motor operation process, the servo motor rotary encoder (pg.) will instantaneously speed by a1s64ad module into a digital signal into the plc, and then calculate the instantaneous volume diameter, and then according to the size of the calculated volume diameter change the output torque, so as to achieve stable and regular control of tension.
±8v corresponding torque, ±8v input when the corresponding output torque can be used in the servo system no.26 # parameters to change, for example: no.26 = 50%, reflecting when the input voltage is ±8v, the corresponding output torque = torque ×50%.