Predictive PI control and its robust stability analysis

It is difficult to analyze robust BIBO stability of predictive PI (PPI) control system due to the time delay of process. A novel technique for stability analysis of this kind of system is proposed in this paper. The state space form of PPI control system is given, and its characteristic polynomial is derived by a simple method, so the robust BIBO stability analysis of this kind of system is also the analysis of corresponding characteristic polynomial. Applying Kharitonov theorem and edge theorem, the BIBO stability can be judged for arbitrarily given process parameter intervals. The system robust stability with variable process parameters is described respectively, and some beneficial conclusions for the design of PPI controller are obtained.