Fault Tolerant Switching Control Based on Adaptive LQG and Fuzzy Controllers

This paper describes a fault tolerant switching control study case for a three water tank laboratory setup with sensors and actuators redundancies. Fault diagnosis and tolerance are two main characteristics of intelligent setups when closed-loop control is used for large complex systems. For instance plant-wide performance relies on distributed fault tolerant control. Discrete adaptive LQG (linear quadratic) and Fuzzy fault tolerant controllers, for nominal situation, are presented and tested in the laboratory setup. For abrupt fault situation, switching from one controller to another based on controller performance evaluation using PCA (principal component analysis) technique is necessary. The main contribution is the performance assessment based on a sliding window and Mahalanobis distance, using T2 statistics. Experimental results applied to a three-tank laboratory setup in the presence of abrupt fault are shown to evaluate the performance of the proposed approach.