Interval Observer-Based Secure Estimation for T–S Fuzzy Systems Under Stealthy Attacks

This article focuses on the interval state estimation for Takagi–Sugeno (T–S) fuzzy systems under stealthy sensor attacks, where the premise variables are unmeasurable. To deal with the stealthy attack, an upper and lower bounds estimation method for the attack is proposed, where the nominal and auxiliary matrices are introduced to overcome the difficulty of ensuring the error system nonnegativity induced by fuzzy rules. Then, based on the bounds, an attack-resistant interval observer is constructed to achieve secure state estimation, and the estimation accuracy is improved using the $H_{\infty }$ technique. Compared with the existing interval observer for T–S fuzzy systems, the designed interval observer has better resilience performance when the system is under stealthy attacks. Finally, simulation examples are provided to illustrate the effectiveness of the proposed results.