Quality and uniformity control of fiber web by roller card system. Part II: Design and validation of a roller card control system

Abstract

Thin web is produced from flocks of raw fiber after being processed by a carding system. In the conventional carding machine, the multi-roller design of the system has dynamic characteristic of time delay, and the quality of web output evenness is affected by the control methods. Based on the new mathematical model of a carding machine, this paper employed a new carding control system and fiber optic sensor to establish a new carding control system. The proposed improved model predictive controller is developed to solve the problem of time delay in the roller carding system using a discrete state and linear quadratic objective function, in order to minimize the deviation between predictive output and given target value. The designed controller is compared with the proportional plus integral (PI) controller based on the conventional control theories and state feedback integral controller using modern control theories as well. In experimental verification, the fiber optic sensor is installed to measure web output at the doffer, a feeding roller is controlled to change the feeding of raw cotton. The results confirm that the proposed improved model predictive controller can be provided not only to enable the output response reach the control objects also improve the production efficiency of the carding machine and enhance the web output evenness.