Tension control mode is generally divided into open-loop control mode and closed-loop control mode.
The open-loop control uses a motor with similar winding characteristics, n = KD (n is the speed, K is the constant, D is the diameter of the winding roller) to drive the winding mechanism directly, so as to obtain approximate constant tension operation.
The open-loop control has poor randomness and low control accuracy.
There are two kinds of closed-loop tension control: direct tension control and indirect tension control.
In the actual production process, the adjusted quantity, i.e. tension, is fed back, compared with the given tension, and then the controlled object is adjusted by using the difference value on the regulator to make the output tension meet the actual demand. This control method is called direct tension closed-loop control.
This method does not need to consider all kinds of compensation, and can eliminate the steady-state error;
Indirect tension control uses the characteristic curve of motor speed torque to control the torque by controlling the speed, so as to achieve the purpose of tension control, but this method needs dynamic and static compensation. Sometimes, in order to get more accurate control performance, the composite tension control method is used, that is, the control amount required is determined according to the 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 to fine tune.
