Dynamic transition control structure for a class of SISO nonlinear systems

Most chemical processes are nonlinear in nature and large setpoint changes or load disturbances make such processes more challenging for control. Rece ntly a simple transition control structure was introduced so that the trade off between nominal performance and robust stability of the model with larg e uncertainties is converted into the development of several models with sm all uncertainties in such a way that the former problem can be solved satis factorily. In this work, a modification to that transition control structur e is proposed to address nonlinear systems. The performance of this transit ion control structure is demonstrated on a nonlinear pH neutralization proc ess. The simulation results show that the proposed structure has good prope rties not only for setpoint changes but also for disturbance rejection.