Reachable set estimation for Takagi-Sugeno fuzzy systems against unknown output delays with application to tracking control of AUVs

• Published in: ISA transactions Vol. 78; pp. 31 - 38
• Main Authors: Zhong, Zhixiong, Zhu, Yanzheng, Ahn, Choon Ki
• Format: Journal Article
• Language: English
• Published: United States Elsevier Ltd 01.07.2018
• Subjects: Autonomous underwater vehicle (AUV); Reachable set estimation; Tracking control; Unknown output delays; Autonomous underwater vehicle (AUV); Tracking control; Unknown output delays; Reachable set estimation
• ISSN: 0019-0578; 1879-2022; 1879-2022
• DOI: 10.1016/j.isatra.2018.03.001

In this paper, we address the problem of reachable set estimation for continuous-time Takagi-Sugeno (T-S) fuzzy systems subject to unknown output delays. Based on the reachable set concept, a new controller design method is also discussed for such systems. An effective method is developed to attenuate the negative impact from the unknown output delays, which likely degrade the performance/stability of systems. First, an augmented fuzzy observer is proposed to capacitate a synchronous estimation for the system state and the disturbance term owing to the unknown output delays, which ensures that the reachable set of the estimation error is limited via the intersection operation of ellipsoids. Then, a compensation technique is employed to eliminate the influence on the system performance stemmed from the unknown output delays. Finally, the effectiveness and correctness of the obtained theories are verified by the tracking control of autonomous underwater vehicles. •The main purpose is to establish an effective method to countervail the negative influence from unknown output delays. The main contributions of this paper are represented as follows:•The reachable set estimation is established for T-S fuzzy systems with unknown output delay signals in continuous-time domain as the first attempt.•Combined with reachable set estimation, observer design, and compensation techniques, the negative influences from unknown time delays to control performance can be removed.