This paper presents a Proportional-Integral observer (PIO) that allows simultaneous states and unknown input estimation. The goal of this observer is to perform actuator fault estimation for a distillation process by using a simplified mathematical model. This model describes the intrinsic physical characteristics of the process through a descriptor Linear Parameter Varying (LPV) approach. The stability of the observer is analyzed through a Lyapunov stability theory. The proposed scheme estimates a fault in a peristaltic pump that feeds the distillation column. The main contribution is demonstrating the generalization of the descriptor LPV approach, expanding the potential applications of modern control strategies for fault estimation in nonlinear processes, especially in distillation plants.
