DC servo motor control for web slitter The common deviation control system has gas-liquid and photoelectric servo control systems. Both work the same way, the only difference is the difference in the detection device. The former is a pneumatic detecting device and a gas and liquid servo valve, and the latter is a photoelectric detecting device and a DC servo motor. They have their own strengths. The photoelectric detection device and the DC servo motor can be used to control the system. The system has the characteristics of fast signal transmission, convenient feedback, convenient installation of photoelectric detecting device, etc., but the system is more complicated.

          The following briefly analyzes the control principle of the system. The system consists of a photoelectric detection device, an electric amplifier, a DC servo motor, and a coiler. The photoelectric detecting device is used for detecting the lateral deviation and direction of the paper tape, and is composed of a power source and a photocell receiver. The bridge circuit is constructed by using a photocell as a bridge arm, and the output voltage signal is a deviation signal of the deviation of the reaction band and is sent to the amplifier. When the tape runs normally, half of the phototube receives light, its resistance value is R1=a, the adjustment resistors R2 and R3 make R1*R3=R2*R4, and the bridge balance has no output. When the paper bag is deviated, the light received by the photocell changes when the belt edge deviates from the central position of the detecting device, and the resistance value also changes, causing the bridge to lose balance, thereby generating a deviation signal. The signal is amplified by the amplifier and input to the DC servo motor. After the DC servo motor obtains the signal, it rotates forward or reverse, and then the winding portion of the ball screw pair on the ball screw pair is tracked in the direction of the deviation. When the displacement of the tracking and the deviation is equal, The deviation signal is equal to zero and the reel stops moving. The coiling process is completed in a new equilibrium state, and the automatic correcting process is completed. In addition, the detecting device is mounted on the winding portion bracket, so that the detecting device moves with the movement of the bracket, and after the tracking of the detecting device is completed, the deviation signal of the detecting device is 0, thereby forming automatic correcting control.