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This paper proposes an adaptive optimal control strategy of finite-time control for high-order uncertain strict-feedback nonlinear systems. Firstly, a reinforcement learning (RL) based an optimal control scheme is employed to design a optimal controller, to achieve global optimisation. Additionally, considering the unmeasurable states, we construct a fuzzy observer and utilise fuzzy logic systems to approximate the unknown functions. Meanwhile, the inclusion of command filtering and time-based control simplifies the controller design and enhances the system's response rapidity. Finally, the effectiveness and feasibility of the proposed approach are validated through a numerical simulation and a single link-robot system simulation. [ABSTRACT FROM AUTHOR]

This paper proposes a novel incipient fault estimation and fault-tolerant control approach for wireless power transfer (WPT) systems with disturbances and incipient sensor faults. Firstly, the dynamic models of the WPT system and incipient faults are established. Then, a k-step incipient fault estimation observer method is analyzed for estimating the states and incipient faults of the system. Based on it, a nonlinear dynamic output feedback fault-tolerant controller is devised to ensure the stability of the WPT system when considering incipient faults and disturbances. Further, the designed controller can monitor the system in real time without the knowledge of the system states. Besides, the stability analysis approach is rigorous, and the proof method can also apply to other similar systems. At last, the simulation example shows that the proposed fault diagnosis method is correct and effective. [ABSTRACT FROM AUTHOR]

This paper focuses on the trajectory tracking problem of nth-order uncertain nonlinear systems with sensor faults. The proposed approach utilizes a fuzzy observer to estimate the unmeasurable states in the systems. Moreover, the finite-time control strategy and the command filtered technique are added in the controller design. The former aims to enhance the systems' response speed, and the latter is to mitigate the "differential explosion" problem. Meanwhile, the adaptive technique is incorporated to compensate for sensor faults. The boundedness of all the signals within the closed-loop systems is confirmed through stability analysis. Finally, the effectiveness of the proposed approach is verified through two simulation examples. [ABSTRACT FROM AUTHOR]

For battery energy storage systems (BESSs) in islanded AC microgrids, distributed control strategy provides an effective and flexible means to implement frequency restoration, proportional active power sharing and state of charge (SoC) balancing. Nevertheless, the distributed control system is susceptible to potential cyber attacks that break the synchronization and stability. To mitigate those effects, this paper presents an attack-resilient distributed adaptive secondary control for heterogeneous BESSs in islanded AC microgrids. The proposed control method can guarantee the consensuses on BESSs' frequency, active power and SoC simultaneously in the presence of actuator attacks, which only uses the local and neighbor's information. Specifically, the resilience is improved significantly by introducing the dynamic control gains with adaptive updating laws. Furthermore, the stability analysis is applied to assure the robustness. Lastly, the effectiveness of the above discussed conclusions is validated and compared by case studies on an islanded AC microgrid testing system. • The secondary control of heterogeneous BESSs is formulated as distributed consensus tracking problems. • Cyber attack is considered in the secondary control and its adverse effects is mitigated. • An attack-resilience distributed adaptive control protocol is designed to achieve secondary control of BESSs. • The stability of the control is proved rigorously in theory. • Simulations validate effectiveness of the control under cyber attacks in different scenarios. [ABSTRACT FROM AUTHOR]

• The actuator saturation, liquid sloshing and vibration of flexible solar panels are considered. • A novel predefined-time control developed base on sliding mode control. • The upper-bounded stabilization time is explicitly contained in the controller. • An adaptive law without the upper bound of the disturbance is proposed. • An auxiliary system is designed to deal with the problem of input saturation. A predefined-time attitude stabilization for complex structure spacecraft with liquid sloshing and flexible vibration is investigated under input saturation during orbital maneuver. First, the attitude dynamics model of liquid-filled flexible spacecraft is constructed. Meanwhile, the influence of solar panel vibration and liquid sloshing is treated as a disturbance in the controller design. Next, an adaptive predefined-time control scheme is proposed by applying sliding mode control theory. A predefined-time convergent sliding surface and reaching law are designed to ensure the predefined-time fast convergence rate. Furthermore, a novel adaptive algorithm is developed to handle the disturbances from liquid sloshing and flexible vibration, ensuring that the system converges to a small neighborhood of the equilibrium. Additionally, a new auxiliary system is constructed to deal with the effects of input saturation. At last, one simulation case is performed to verify the feasibility and advantages of the proposed algorithm. [ABSTRACT FROM AUTHOR]