ABSTRACT
This work investigates the control design and reachable set estimation problem for T-S fuzzy systems under bounded external disturbances. By designing a fuzzy controller, the reachable set of the closed-loop fuzzy system can be bounded by an ellipsoid that is minimized via two optimization algorithms. When the fuzzy control scheme is implemented under an event-triggered framework, the limited information availability may degrade desired control performance due to only the triggered state being available for the fuzzy controller. To alleviate this problem, a novel reachable-set-dependent event-triggering condition is proposed such that satisfactory control performance can still be ensured by the above fuzzy controller. Meanwhile, the bounding ellipsoid of the reachable set is explicitly given, and a relationship is established between control performance and communication cost under the event-triggered scheme. In addition, under the condition that the reachable set remains within a specified safe area, the communication rate can be reduced while still achieving optimal control performance. The proposed strategies are verified via a simulation example.
ABSTRACT
This article investigates the sliding-mode control issue for interval type-2 (IT2) T-S fuzzy systems under limited communication resources. An event-triggering weight try-once-discard (ET-WTOD) protocol is formulated via two thresholds to determine the transmission of the state signal. The proposed ET-WTOD protocol can dynamically adjust the transmitted nodes and permits only partial components with larger error to be sent at each triggering instant, which is just the key distinction from the existing protocols. Under the imperfect premise matching framework, the controller's membership functions are reconstructed via the received state and the known upper and lower bounds, and then, a new scheduling signal set is established to design the scheduling-signal-dependent fuzzy sliding-mode controller. With the aid of the membership-function-dependent approach, the mismatching premise variables of the fuzzy model and the controller are effectively handled by introducing some slack matrices, while the relaxed stability conditions are derived to ensure the stability of the closed-loop system and the reachability of the specified sliding surface. Moreover, an optimized sliding domain is further obtained via the genetic algorithm (GA). Finally, the proposed control strategy is verified via the mass-spring-damper system.
ABSTRACT
This paper addresses the issue of sliding mode control(SMC) for a class of interval type-2(IT2) fuzzy system subject to the fading channel. For relieving the transmission burden, a dynamic event-triggered mechanism is introduced to determine the transmission of the measurement signals via the sensor-to-controller(S/C) channel. In the communication channel, the transmitted signal may suffer from fading in wireless communication networks. By means of known bounds of the membership functions (MFs) in IT2 fuzzy model, both the fuzzy state observer and the fuzzy SMC law are designed to ensure the reachability of the sliding mode dynamics. Meanwhile, stability conditions involving the fading parameter are obtained to guarantee that the input-to-state practical stability in mean square of the closed-loop systems. Finally, the proposed control scheme under the fading communication is verified by virtue of the numerical simulation and the tunnel diode circuit.
