Cyber attackers attempt to disrupt microgrid operations by manipulating time synchronization and creating delays in transmitted packets. To overcome the non-availability of time stamped data due to the time delay attack, this paper presents a fractional-order model for a delayed typical microgrid and proposes an adaptive finite-time terminal sliding mode tracking controller for fractional-order renewable microgrids. The proposed method exploits the benefits of finite time trajectory error, online adaptation, and fractional-order modeling. It ensures the finite-time convergence of tracking errors to the origin by utilizing a fractional-order switching surface and online adaptation of upper bounds of perturbations. Simulation results of load frequency control in a typical microgrid using the proposed method are presented and compared with those obtained by other methods. Test results and stability proof show that the proposed method can execute the load frequency control with high accuracy and a fast response.

This paper designs and implements a chattering-free terminal sliding mode control approach for a class of chaotic systems with unknown uncertainties. It considers sliding mode control (SMC) to deal with the dynamic model uncertainties of the chaos system, and uses a combination of SMC with an adaptive control approach to solve the upper boundaries problem of unknown model uncertainties and their estimation. Chattering is completely eliminated without over estimating the control gains by adopting an adaptive continuous barrier function in the dynamic switching function. Using the Lyapunov’s stability theory, it was shown that the proposed scheme can guarantee the convergence of system states to the vicinity of the sliding surface in finite time. Additionally, the adoption of a sliding surface with a nonlinear and integral switching function resulted in removing the reaching phase of the sliding surface and yielding a controller that is robust to uncertainties from the start. The effectiveness of the proposed control method was assessed using three scenarios implemented to a Liu’s uncertain chaotic system in MATLABSimulink environment. The obtained results confirmed the ability of the proposed approach to achieve continuous and smooth control rules for such chaotic systems. Among the main attributes of the proposed control method are its ability to completely eliminate chattering and yield a robust performance against model uncertainties and unknown external disturbances; common issues in chaotic systems.

This paper proposes an event-triggered control technique based on an adaptive barrier function higher-order global sliding mode control for a class of quadrotor unmanned aerial vehicles subject to model uncertainties and unknown external disturbances. The event-triggered control technique is considered to increase the sampling interval of the control signal updates, and at the same time, maintain the stability and increasing the overall efficiency of the controlled system. Lyapunov's stability theory is considered to derive the adaptive continuous barrier function so as to completely eliminate the chattering phenomenon typically associated with sliding mode control. The designed control law is smooth and continuous, and the system's states converge to a predetermined bound around the switching surface at a finite time. The effectiveness of the suggested control method is assessed using a simulation study in MATLAB-Simulink environment, and considering a comparison analysis with other prevalent approaches. The proposed control scheme can also be used for finite-time fault-tolerant control of various types of quadrotors such as infrared obstacle-avoidance quadrotor subject to time-delay and input saturation.

Floating offshore wind turbines harness more vigorous and more stable winds, making them a promising solution for clean energy. However, their stability is compromised by sea waves and sudden winds, reducing power extraction. To address these challenges, this paper proposes a finite-time fractional-order adaptive SMC for tension-leg platform wind turbines to enhance stability and efficiency. A fractional-order model ensures accurate system representation, while a barrier-function-based adaptive control strategy guarantees rapid, finite-time convergence, mitigates chattering, and suppresses external disturbances through real-time estimation. The proposed controller effectively stabilizes the system, helping to maximize power extraction. Simulation results in the MATLAB-Simulink environment demonstrate superior performance compared to conventional methods in terms of disturbance rejection and convergence speed. Furthermore, hardware-in-the-loop validation using a Speedgoat platform confirms the method's real-time feasibility and robustness under realistic operational conditions. The proposed approach offers a significant advancement in floating offshore wind turbines stability and control, ensuring efficient energy harvesting even under severe environmental disturbances. These findings contribute to the development of more reliable and resilient floating wind energy systems, supporting the transition toward sustainable offshore wind power.

In this paper, the theory of control is considered on nonlinear systems. A closed-loop controller with a strong idea has been introduced to track system states and guarantee asymptotically stability. The proposed method is the indirect terminal sliding mode control technique based on adaptive and fuzzy rules, which has used the continuous barrier function as a new approach in its design to improve the performance of this controller. One of the significant challenges in the sliding mode control method is the chattering phenomenon due to the discontinuous sign function in the control law. In the proposed approach, the control law is obtained continuously and smoothly due to the mentioned continuous function and subsequently solves the chattering problem. Another feature of the proposed method is the asymptotical stability of the system dynamics within finite time, which is proved based on the Lyapunov function. The proposed Lyapunov function includes the function of fractional power of a sliding surface. On the other hand, the obtained control law using the sliding mode method is estimated using the fuzzy system. The adaptive approach adjusts the fuzzy law parameters and the unknown bound of external disturbance.