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In this paper, a fractional-order Dadras-Momeni chaotic system in a class of three-dimensional autonomous differential equations has been considered.Later, a design technique of adaptive sliding mode disturbance-observer for synchronization of a fractional-order Dadras-Momeni chaotic system with time-varying disturbances is presented. Applying the Lyapunov stability theory, the suggested control technique fulfils that the states of the fractional-order master and slave chaotic systems are synchronized hastily. While the upper bounds of disturbances are unknown, an adaptive regulation scheme is advised to estimate them. The recommended disturbance-observer realizes the convergence of the disturbance approximation error to the origin. Finally, simulation results are presented in one example to demonstrate the efficiency of the offered scheme on the fractional-order Dadras-Momeni chaotic system in the existence of external disturbances.

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This paper proposes a disturbance observer-based Sliding Mode Control (SMC) approach for the robust synchronization of uncertain delayed chaotic systems. This is done by, first, examining and analyzing the electronic behavior of the master and slave Sprott chaotic systems. Then, synthesizing a robust sliding mode control technique using a newly proposed sliding surface that encompasses the synchronization error between the master and slave. The external disturbances affecting the system were estimated using a disturbance observer. The proof of the semi-globally bounded synchronization between the master and slave was established using the Lyapunov stability theory. The efficiency of the proposed approach was first assessed using a simulation study, then, experimentally validated on a data security system. The obtained results confirmed the robust synchronization properties of the proposed approach in the presence of timedelays and external disturbances. The experimental validation also confirmed its ability to ensure the secure transfer of data. INDEX TERMS Sliding mode control; robust synchronization control; chaotic systems; disturbance observer; data security.

This paper considers a fractional-order quadratic chaotic flow with nonhyperbolic equilibrium in a class of three-dimensional autonomous differential equations. Afterward, a design technique of adaptive sliding mode disturbance-observer for synchronization of fractional-order quadratic chaotic flows with nonhyperbolic equilibriums and time-varying disturbances is offered. Applying the Lyapunov stability concept, the recommended control method satisfies that the states of the fractional-order master and slave quadratic chaotic systems are synchronized quickly. Whereas the upper bounds of disturbances are unknown, an adaptive regulation scheme is advised to estimate them. In the following, the proposed disturbance-observer realizes disturbance approximation error. Finally, simulation results are presented in three different examples to exhibit the effectiveness of the offered method on the fractional-order quadratic chaotic systems in the presence of external disturbances.

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This paper proposes an adaptive integral-type terminal sliding mode approach for the attitude and position tracking control of a quadrotor UAV subject to model uncertainties and external disturbances. First, an integral-type terminal sliding tracker is designed to attain the quadrotor UAV tracking performance in finite time when the upper bound of perturbations and uncertainties are known. Next, an adaptation law is proposed and a modified parameter-tuning integral-type terminal sliding mode tracking control scheme is designed to compensate of the model uncertainties and external disturbances. The stability and finite time convergence of the proposed approach is verified using the Lyapunov theory. Its performance is assessed using a simulation study encompassing various scenarios. Low chattering dynamics, fast convergence rate, and absence of singularities are the main features of the proposed approach.