Integrated multi-PI control of a CSTR based on gap metric

The PI control technique is mature and classical. And most of the actual industry control systems employ the PI controllers. However, for the strong nonlinear systems with wide operating ranges or big disturbances, such as the continuous stirred tank reactor (CSTR) system, a single PI controller is unable to satisfy the control requirements. In order to make full use of the merits of the classical PI algorithm, this paper proposes an integrated multi-PI control method based on gap metric for a nonlinear CSTR system. In the proposed method, the multi-model decomposition of the CSTR and local PI controller design is integrated into a combination by the gap metric. Thus, the local models are reduced, dependence on experience is relieved, computational load is decreased, and the closed-loop control performance is improved.