Internal model control with feedback compensation for uncertain non-linearsystems

Control of non-linear systems by model-based strategies is often affected b y model uncertainties. For these systems, internal model control with feedb ack compensation (IMC-FC), which consists of a non-linear model control and an error feedback loop, to achieve disturbance attenuation and offset-free performance, is proposed in this study. The matching conditions for the un certainties of non-linear systems are not necessary, and adjustable paramet ers can easily be tuned to satisfy the particular specification. The underl ying theoretical approach for the feedback compensation is the Lyapunov sta bility theory. The effectiveness of the proposed approach is illustrated by a simulation example on the composition control of a continuous stirred ta nk reactor. The theoretical analysis and simulation results show that the p roposed IMC-FC can reduce the effect of modelling uncertainties such that t he performance of the control system is greatly improved.