T-S Fuzzy Logic Based Modeling and Robust Control for Burning-Through Point in Sintering Process

Burning-through point (BTP) control is the key to guranteeing the sintering process and sinter quality. Due to an opening combustion and multiple input conditions, the combustion process of the sintering process shows a typical characteristic of time-varying operation conditions. This paper analyzes the influence factors resulting in time-varying operation conditions and then constructs an improved Takagi-Sugeno (T-S) fuzzy model of BTP based on the linear parameter varying (LPV-TS-BTP model), in which the BTP temperature and the central bellows temperature are taken as time-varying parameters. The model explains how the different working conditions change the systems dynamics and describes this time-varying nonlinear model in the form of a linear combination model. Then, a fuzzy robust control method based on the LPV-TS-BTP model is designed by using the parallel distributed compensation principle to realize the BTP control of complex process, in which the controller parameters are achieved by using the linear matrix inequality (LMI) method. The simulations about modeling and control, which are carried out on a semiphysical simulation platform for the sintering process, verify that the model has a high prediction accuracy, and the fuzzy robust control makes BTP stable around a given bellows.