State Feedback Temperature Control Based on a Smith Predictor in a Precalciner of a Cement Kiln

This paper proposes the design of a state feedback controller based on a Smith predictor for effective temperature control in the precalciner of a cement rotary kiln. The dynamic model of this process is obtained from real-time data by applying the system identification approach. This identification procedure yields a fourth order transfer function with dominant time delay. The validation results showed that the model obtained describes with a high degree of adequacy the dynamic behavior of the process under study. A state feedback controller combined with a Smith predictor is therefore designed which behaves robustly against the effects of external disturbances and dynamic uncertainties. Simulated results compare the performance of the proposed controller with a standard PID controller. Two performance indexes have been used in this comparison: the integral absolute error, and the control effort. Simulations show that the proposed controller provides lower values of these indexes and, therefore, outperforms the standard PID controller in terms of performance and robustness.