(1) direct tension control method: also known as feedback control, can be divided into two types: AB (a) the actual tension is detected by sensors such as tensiometers, and the measured value is used as a feedback signal to form a tension closed-loop system, that is, the measured actual value is compared with the given tension, and the deviation produces a control effect, so that the actual tension is equal to the given tension. According to the different sensor structures, it can be divided into position control and feedback control. (b) Loops are used to establish tension and measure the looper amount to form a looper feedback control system, and the looper amount is controlled to keep the product tension constant. The tension control method is suitable for high-precision and high-speed tension control occasions, and has the advantages of high control precision and good real-time performance.
(2) Indirect tension control method: also known as compensation control, which indirectly maintains tension stability by adjusting the parameters that affect tension stability, that is, only given the set value of tension, the actual value of tension is not collected by the detector, so that tension is not closed-loop, but indirectly controlled by controlling the current or excitation current of the controlled machine, that is, the driving motor, so as to keep the motor torque constant and ensure the tension of coiled products constant.