Feedback linearization-based PI controller for continuous pH process system

This research proposes a study of Nonlinear Feedback Linearization-Based PI controller for a continuous pH process system. We control the pH by filling in a reactor tank with wastewater and sodium hydroxide (NaOH) 1.25% by-weight. The system then keeps track of the pH to the desired values. However, since the system is inherently nonlinear and highly sensitive to uncertainty disturbances, it is not easy to achieve the desired results with rapidness and accuracy. In this paper, a nonlinear model is built taking the case of overflow reaction. The controller is designed based on feedback linearization in the inner control loop as a technique to transfer the system into a linear one, with Proportional - Integral (PI) Controller in the outer control loop. From the simulation results, the proposed Nonlinear Feedback Linearization-Based PI controller scheme has good steady state and satisfactory dynamic tracking performance.