Nonlinear PI/PID controllers for a high-order reactor system

The study is carried out on temperature control of a high-order reactor system subject to physical input constraint and output multiplicity. Since many process states are immeasurable in the real-time evaluation and thermal effects of exothermic reactions usually tend towards operation with stability margins, nonlinear control algorithms derived from the state-space formulation of model-based controller design for nonlinear relative-degree-one and relative-degree-two systems are addressed. With the aid of the equilibrium-based design, the nonlinear PI and PID-types control frameworks are more amenable to industrial implementation. Additionally, the tuning procedure with two controller parameters is relatively simple and straightforward. Through numerical simulations, the low-and-high gain technique and anti-reset windup design are added to enhance the process control performance.