The Analysis And Research On The Dynamic Characteristics Of HAGC System Of Rolling Mill Based On The Dynamic Friction

This paper makes a study on the hydraulic auto gague control(HAGC) system in rolling mill, based on the study home and abroad, in order to know the influence on the HAGC system's dynamic characteristics because of friction.First, in order to study HAGC system as a whole targeted research, this paper established a nonlinear model for asymmetric cylinder based on the many scholars's research and established a system with multi-degree of freedom mechanical model of the load for the mill's vertical load characteristics. Taking into account the pipe system and other factors including leak, pipes, multi-degree of freedom load, this paper established a whole HAGC system dynamic model and made a good foundation for study further.Then, this paper analysis the development of tribology and the friction model, and compared the pros and cons of various friction models. Then this paper chose the Lugre friction model which is good at both the characteristics of the various parties and the performance of selected nature of the dynamic friction.In order to determine the static and dynamic friction model parameters, this paper first made a simple analysis on the mathematical friction model and find some laws. Then this paper took two kinds of search methods, manual search and genetic algorithms search. Then this paper make a identification on the friction model parameters whit a great deal empirical supporting data, and got some realistic parameters, and finally know these parameters'influence on the system by small change the range of each parameter. Then it determined the parameters by comparing different signals affect the accuracy.Then put the analysis of the friction model in HAGC system model to analyze the dynamic friction's influence on the system's time domain and frequency domain dynamic changes. The article also analyzed the damping characteristics after add the dynamic friction model and the obtained the equivalent damping ratio through system identification method. The results found in the experiment on the 300 rolling mill, comparing simulation results, show the accuracy of the simulation model and the important role of the dynamic friction in HAGC system of the rolling mill.