Hybrid Piecewise Affine Modeling of Cement Grinding Mechatronic Systems

Interaction of continuous and discrete dynamical behavior yields to the formation of hybrid models. Various models have been developed to represent the dynamics of hybrid systems. In this paper, hybrid modeling of cement grinding system is studied. Cement grinding plant possesses nonlinear dynamics with an intractable and costly control routine. Further to the nonlinearity, the plant's dynamics varies upon sever changes in working conditions. Hence, piecewise affine modeling method is a proper candidate that enables the onset of nonlinear system control with a set of linear controllers. Hybrid modeling necessitates the precise identification of parameters affecting the quality of output cement such as input values and cement grinding pressure difference. Therefore, in this study, a piecewise affine model is developed for all pressure differences into three intervals. By this method, it is shown that the hybrid model shows a better performance compared to the uniform models. Furthermore, three simple linear controllers can be applied rather than a nonlinear controller. Simulation results revealed the merits of the proposed method as the model output is close to actual behavior even while the plant's dynamics is changing. Another core contribution of this method is the major reduction in cost and complexity of controller design for huge cement grinding plants.