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This paper compares backstepping controller and fast terminal super twisting sliding mode controller (FTSTSMC) approaches for position and altitude control of quadrotor in the presence of constrained disturbances and uncertainties. As conventional SMC which ensures only asymptotic convergence, a new sliding surface is made that allows the tracking error to quickly go to zero in a set amount of time. For achieving above condition based on the super-twisting algorithm, a control law is made that both removes the chattering and handles the quick convergence. The stability in terms of convergence to zero of the entire closed loop system in finite time is examined using the mathematical formulas and the Lyapunov stability theory. Using MATLAB simulation, the proposed controller's robustness and effectiveness are compared against backstepping control technique.

This paper presents the adaptive terminal sliding mode control (ATSMC) for robotic manipulators using input quantization in the presence of uncertainties and external disturbance. The concept of adaptive quantized control for robot manipulator systems is explored in this study, which involves the introduction of a novel approach for creating input quantization with hysteretic quantizer. Initially, the approach involves suggesting adaptive terminal sliding mode, followed by the application of a hysteretic quantizer incorporating quantization error bounded within specific sectors for controlling the input signal. The proposed adaptive quantized control technique eliminates the chattering and provides convergence to origin in finite-time. The proposed control algorithm's effectiveness is shown through simulation results, illustrating its successful application in controlling a two-link robotic manipulator.

This brief presents the event-triggered control (ETC) for linear parameter varying (LPV) model of boost converters. We examine the nonlinear dynamics of boost converters in the LPV framework. The proposed controller is duty-ratio-dependent and provides better performance while requiring less computation. Using the parameter-dependent Lyapunov function (PDLF), we demonstrate the stability analysis of the proposed approach. Furthermore, we demonstrate that the inter-event time is lower bound by a positive constant, which indicates Zeno behavior free performance. In comparison to earlier time-invariant synthesis techniques, the LPV formulation offers for increased robustness and performance properties. Simulation and experimental results validate the effectiveness of the proposed method.

This paper addresses the problem of attitude tracking for a 2-Degree of Freedom (DOF) helicopter system with uncertainties. Euler-Lagrange equations are utilized to develop a nonlinear model for the helicopter, considering the control input constant coefficients and system parameters as unknown. The prescribed-time control approach is proposed using adaptive backstepping to track the desired pitch and yaw positions separately. In Addition, a constrained function is also used to avoid the risk of a larger signal when time gets closer to the appointed settling time. Through the application of the theory of Lyapunov stability, it is shown that the proposed strategy ensures that all closed-loop signals are bounded, and all the states converge within the prescribed time. A significant advantage of this approach is the ability to pre-specify the upper bound of the settling time. Finally, the efficacy and control capabilities of the proposed scheme are verified by obtaining the simulation results on the Quanser 2-DOF helicopter.

This paper presents a time-discretization methodology for designing a control law for stabilizing a continuous plant. It relies on the concept of immersion and invariance principle with implicit-Euler discretization of Twisting algorithm. The multi-valuedness of the signum function on the off-the-manifold is fully utilized by this discretization. By eliminating numerical chattering in the control input and system output, the resulting controller ensures a smooth stabilization of the off-the-manifold. Additionally, the exogenous disturbance that is currently affecting the system is diminished by a factor of h (h is the sampling interval) as well. The efficacy of proposed technique are shown through comparative study in the simulations.

This paper proposes a leader-follower formation tracking control problem of autonomous unmanned systems with switching directed topologies, where the leader is dynamic. It is considered that the followers have only access to the leader's position. The distributed observer is designed to estimate the velocity of the leader for each follower. Based on the estimated states, this paper presents a distributed formation tracking control algorithm. Using multiple Lyapunov functions (MLFs) stability is ensured. For dealing with switching topologies, the average dwell time (ADT) concept has been used, which relaxes the traditional dwell time restriction for switching topologies. Finally, a numerical simulation demonstrates the theory's effectiveness.

This paper proposes a sliding mode approach for leader-following formation control of perturbed second-order autonomous unmanned systems (AUSs) under directed topology. The leader velocity is assumed to be constant. The formation controller performs two objectives: (i) it obtains the formation control of all the followers, (ii) it achieves the velocity consensus of all the followers. Using Lyapunov stability theory, we have presented the finite-time convergence of sliding surface and asymptotic stability of the closed-loop system. Finally, a numerical example with comparative results demonstrates the efficacy of the proposed method.