Iterative Learning Control Of LF Alloy Weighing System

Alloy weighing system plays an important role in LF production process. It has a significant influence on the product quality, even determines the character of the products. As a result, a precise control of the alloy weighing system is needed. But the level of automation of most modern alloy weighing system is low, it causes that a lot of human and material resources are wasted. Therefore, it’s imperative to make researches on dynamic alloy weighing system with high credibility, high efficiency and simple architectures.In this thesis, the process of LF craft and the component of equipment are introduced by consulting a great deal of literatures in the country and abroad, the present research development of LF alloy weighing system is summarized. From the whole structure of alloy weighing system, vector control of asynchronous motor and vibration feeding which are two major sections of alloy weighing system are studied, their mathematical models are established for that the dynamic alloy weighing control need it, and also the models of two sections are validated by simulations.A method based on Iterative Learning Control (ILC) is used for the controller designing, according that the alloy weighing system has the characters of nonlinear, time-varying, high inertia and random, besides, the control process is a repeating one. Precisely, the method is a PD type open-closed loop iterative learning. The alloy weighing process can respond rapidly and accurately by using the controller. What’s more, a method of parameters optimization is applied to determine the parameters of the controller. In addition, based on a LF practical application of computer control system, the composition of the system are described, in particular, part of the alloy weighing hardware, software environment and functional realization are researched. And the flow chart of alloy weighing program is designed.In the end, on the basis of summarizing the whole research work, the trend for the future development of LF alloy weighing system is pointed out.