The tension control method is generally divided into two types: open loop control mode and closed loop control mode. The open loop control is to directly drive the winding mechanism
with an electric motor having a similar winding characteristic n = kD (n is the rotational speed, k is a constant, and D is the diameter of the winding roller) to obtain an approximate constant
tension operation. The open loop control has poor randomness and low control precision. The closed loop tension control has two kinds of direct tension control and indirect tension control.
In the actual production process, the volume is adjusted, that is, the tension is fed back, compared with the given tension, and then the difference is applied to the regulator to adjust the controlled
object so that the output tension meets the actual demand. It is called direct tension closed-loop control. This method can eliminate the steady-state error without considering various compensations.
The indirect tension control uses the motor speed-torque characteristic curve to control the torque to control the torque, so as to achieve the purpose of controlling the tension. This method requiresdynamic and static compensation. Sometimes, in order to obtain more precise control performance, a composite tension control method is adopted, that is, the required control amount is first determined according to an indirect control algorithm, and various compensations are considered to make the indirect control as accurate as possible, and then the direct tension control is used for fine adjustment.