Development of Simulation System and Adaptive Controller to Improve Mould Level Control Accuracy in Continuous Casting Process

摘要

In the continuous easting process, mould level fluctuation has a negative effect on slab quality, especially for the occurrences of longitudinal crack, transversal crack, short longitudinal crack, and slug entrapment and inclusion. In this research, a computer simulation system for the dynamic fluctuation of the mould level was built, with all physical model influence factors being included, such as the weight of molten steel in ladle and tundish, the control system of sliding gate for sub-nozzle control, and the variations of casting speed and mould size. To utilize the production and experimental data, the parameters of the model were calculated by system identification. The main advantage of establishing the computer simulation system is that the risk of on-line trials and damages can be avoided, and the influence of process parameters and control gains on system response can be evaluated via off-line simulation. The other contribution of this research is the development and the implementation of a specific adaptive controller, which not only improves the control accuracy of the mould level control system, but also lessens the occurrence of short longitudinal crack on the slab surface, allowing better quality hot-rolled plate to be produced.