Robust Output Feedback Linearization Control of Nonlinear CSTR via the Grey Wolf Algorithm and Kharitonov-Based Stability

This academic paper develops a novel combination of multiple control design techniques to generate a robust nonlinear control strategy for a Continuous Stirred Tank Reactor (CSTR). The core challenge is maintaining optimal performance when essential parameters such as reaction kinetics and heat transfer coefficients are unknown but bound. The main contribution is the synergistic use of a Grey Wolf Optimizer (GWO) to concurrently tune the gains of both a High-Gain Observer (HGO) and a feedback linearization controller, realizing a balanced and high-performance system. The methodology combines HGO-based state estimation with a feedback linearization controller. Furthermore, Kharitonov's theorem formally guarantees closed-loop stability under parametric uncertainties. The proposed controller was validated through simulations conducted under realistic operating conditions, proving its ability to robustly track temperature setpoints with faster settling time and smaller overshoot, even in the presence of variations in system parameters and external disturbances. In conclusion, this work establishes a systematic framework for employing advanced control theories to increase the efficiency and stability of a nonlinear CSTR plant.