| Nowadays, the automobile industry as well as furnishment manufacturing, has anexplosive growth in China. And at meanwhile the demand for steel, especially thedemand for strip steel has increased fast. Most strip steel production adopts serializedcoiling technics, and the coil of strip steel is the last step in tandem rolling. Theposition control is a key point in strip steel coiling processs, which can make sure thatthe strip steel is in the center position or the edge of the strip steel is orderly, and it isbenefit for safe production, packetting, transportation, and decreasing the cuttingamount of strip steel, which can enhance economic efficiency greatly.Responds fast, high definition, high power mass ratio and high-power, those allare technical characteristic of electro-hydraulic servo system, which makes it haswide adaptability in strip steel position control. How ever, electro-hydraulic positionservo system is a typically electro-hydraulic coupling system, its character isnon-linear, uncertainty, time-varying, external disturbance, cross coupling disturbanceetc. In addition, it is also affected by grease viscosity, temperature, and workcondition, so it is very difficult for us to construct exact math model of the system.And thinking about that the normal PID control can not adapt modern demand toelectro-hydraulic servo system, the paper has introduced a rising intelligent controltechnology—Iterative Learning Control.Iterative Learning Control (ILC) is a branch of intelligent control with strict mathdescribe. It needn't find out the exact math model of the system, and only need toknow the state of input and output parameter. And it has very simple algorithm, whichcan make the output tracking to the input exactly within a given time. Especially,ILC is adapt to the situation with repeated function characteristic, and the algorithm isvery easy to be realized by computer.In this paper, the technics and control principle of strip steel position correctionsystem is introduced at first. And the mathematical model of the electro-hydraulicservo system is constructed. Then the dynamic performance of the system and theadaptability of PID control are all analyzed in the paper. According to the principle ofILC, the application method about the ILC algorithm applied in the servo system, isexplored mainly in this paper, which including the construction of the algorithmmodel, simulation analysis, and engineering implementation. And it is veryconvenient for us to give an effective, responds fast, high definition and steady control to the different electro-hydraulic servo system only by changing the learningrule accordingly.At last, the paper also presents a modified ILC method—Fuzzy IterativeLearning Control, which colligates the advantage of ILC and Fuzzy Control, it isuseful to promote the robustness of the system. |
PDF Full Text Request