Hot Galvanized Line Air Knife Control Research

With the development of technology, hot dip galvanized sheet showing the current development of a vibrant scene , Galvanized steel can not only effectively solve the corrosion problem, but also according to the different thickness of zinc coating is widely used in various fields.air-knife control precision directly determines the quality and application of galvanized sheet in the hot dip galvanized sheet production process.Galvanized process is a complex process, the existence of a nonlinear, multivariable, large time-delay characteristic, these features make the mathematical model control method is difficult to obtain satisfactory control.PID controller is simple and easy to use,it has goodstability and good control performance etc, but it depends on the parameters that comes form the experience of people,the more complex the systems is,the more difficult to set the parameter good;Smith predictor for large time-delay system for well control,but it depends on the mathematical model of the object,while the actual industriaprocess is very difficult to establish a precise mathematical model;model-free adaptive control theory does not need the mathematical model of the object, only through the input and output data to be able to accurately grasp the characteristics of the current process object.Hot dip galvanizing is a complex non-linear,multi-variable process, and because the thickness of the rearward mounting position, it has the characteristics of large time-delay. Affect the thickness of zinc by many factors, the collation of data through on-site analysis, zinc can be thick impact of various factors on the general rules, but it is difficult to establish a mathematical model close to the actual, therefore, the conventional control method is difficult to obtain satisfactory control performance. These characteristics for the controlled object, this paper proposes the following solution:First, theory using model-free adaptive thinking, Through model-free adaptive algorithm, design a MISO MFA controller;Second, discusses the control system used the advantages and disadvantages of several anti-lag algorithm,an improved model-free adaptive algorithm, And as a predictor to predict the next time the controller output;Third, The Anti-delay MFA controller algorithm combined with Implemented in the LabView programming software, verified with field data control effect of this controller.Simulation results show that the anti-lag model-free adaptive controller to overcome the mathematical model of the object is not charged defects, combination of Smith predictor control advantages of hysteresis systems, not only small overshoot, fast response and high control accuracy, but also has a strong anti-jamming capability, System for large galvanized lag has good control effect.