A new approach to the control of autolevelling for drafting process: part 1: theoretical model based on the discrete-event simulation

This paper presents a new approach to control the autollevelling process to decrease the output unevenness. A discrete autolevelling model is set up based on the balance of the fiber distributions in the drafting zone. The relationship between the velocity of rollers and fiber distributions is pointed out in the light of the discrete autolevelling formula. This model can keep the number of fast-floating fiber constant to eliminate the input unevenness and improve the output quality of strands. By autolevelling the input forms of rectangular wave, sinusoidal wave and random wave, the advantages of this model are illustrated. It is shown that this discrete autolevelling model can decline the abrupt, dramatical or sequential input unevenness and lower the value of output CV more effectively.