Synchronization control of externally disturbed chaotic spacecraft in pre-assigned settling time

This article reports the design of a novel finite-time robust nonlinear controller for the synchronization of two identical chaotic spacecraft. The proposed controller does not cancel nonlinear terms appearing in the chaotic spacecraft dynamics. Avoiding the cancelation of the nonlinear terms of the plant by the controller makes the closed-loop robust stable in the presence of uncertainties in the chaotic spacecraft parameters; this concept blooms base for the design of computationally efficient simple control law. The proposed finite-time robust nonlinear controller (1) synchronizes two nearly identical chaotic spacecraft in finite-time duration, (2) expedites the convergence of errors vector to zero without oscillation, and (3) eradicates the effects of external disturbances. Analysis based on the Lyapunov second theorem proves that the synchronization error converges fast and verifying the closed-loop’s robust global stability. The finite-time stability technique affirms the convergence of the synchronization error to zero in settling time. This research article also studies the effects of the exogenous disturbances and the controller parameter’s slowly smooth variations on the closed-loop performance. The controller parameter variation analysis sets the procedure for tuning the controller parameters. The computer-based simulation results validate the theoretical findings and provide a comparative performance analysis with the other recently proposed synchronization feedback controllers. This article uses Mathematica 12.0 version in the Microsoft 10 environment for all the simulations.

A Robust Nonlinear Controller for PMSG Wind Turbines

In this paper, a nonlinear backstepping controller is proposed to manage the performance of a full-variable permanent magnet synchronous generator wind turbine. This nonlinear controller achieves a rotational speed objective for the generator and is validated through Lyapunov-based stability analysis. Additionally, this objective is accomplished without a measurement for wind speed that influences the wind torque. The proposed scheme is compared to a typical linear controller through simulation results. Simulation tests are performed to compare the response time and average error of each controller in both a drastic and realistic dynamic wind environment. These results demonstrate that the proposed controller is far more robust to wind turbulence than traditional control schemes. The simulation results of this study indicate a 1000% increase in response time and 3000% decrease in average controller error.