Research On Deviation-Correcting Control System In Continuous Galvanized Steel Sheet

Nowadays, in the continuous galvanizing processing line, the strip status, line speed, strip tension and the mounting accuracy of the machine may cause the strip-offline. The strip-offline may have a lot of negative influence on the product quality. Therefore, we need to set specific deviation-correcting control system.The equipment of deviation-correcting system is edge position hydraulic control unit which usually performs strip edge alignment in rolling processes, heat treatment, acid picking and surface treatment of thick and thin plates. It always compensates for the difference, if any, between the set value and the measured value regarding the position of the object to be controlled, while observing and feeding back the measured results. This deviation-correcting system is a typical representative of automatic feedback control system.The main executing agency is the electro-hydraulic servo system, this paper is a research on how to solve some problems which are existing in electro-hydraulic servo system, such as time-varying, external load disturbance, nonlinear and some other issues, then design an appropriate control strategy for controlling this kind of system. Because of electro-hydraulic servo system have these series of uncertainties questions, conventional PID control can not achieve better control effects, but fuzzy control does not need a precise mathematical model, so these systems who have uncertainty, non-linear problems can achieve real-time control easier with fuzzy control. Therefore, this paper will use fuzzy control to command electro-hydraulic servo system.The paper chooses the deviation-correcting system of the continuous galvanizing line loop section of some cold rolling plant as the main role, gives the introduction of electro-hydraulic servo system and the theoretical basis of fuzzy control, design of the fuzzy control system and fuzzy PID control system respectively with the mathematical model of electro-hydraulic servo system, and compared with the conventional PID control system. Through the analysis of simulation results, this paper shows that the design of these control systems can solve the problems well in electro-hydraulic servo system with better control effects, such as better tracking precision, better static and dynamic performance, and so on, proving the feasibility of the design, all of this may helps a lot in designing and improving the strip deviation-correcting system.