Output Tracking of Some Class Non-Minimum Phase Nonlinear Systems via linearization Input-Output

We present an output tracking problem for a non-minimum phase nonlinear system. In this paper, the input control design to solve the output tracking problem is to use the input output linearization method. The use of the input output linearization method cannot be initiated from output causing the system to be non-minimum phase. Therefore the output of the system will be redefined such that the system will become minimum phase with respect to a new output.

Robust Discrete-Time Nonlinear Attitude Stabilization of a Quadrotor UAV Subject to Time-Varying Disturbances

A discrete-time improved input/output linearization controller based on a nonlinear disturbance observer is considered to secure the stability of a four-rotor unmanned aerial vehicle under constant and time-varying disturbances, as well as uncertain system parameters for its attitude behaviour. Due to the nature of the quadrotor system, it contains the most extreme high level of nonlinearities, system parameter uncertainties (perturbations), and it has to cope with external disturbances that change over time. In this context, an offset-less tracking for the quadrotor system is provided with the input/output linearization controller together with a discrete-time pre-controller. In addition, the robustness of the system is increased with a discrete-time nonlinear disturbance observer for time-varying disturbances affecting the system. The main contribution of this study is to provide highly nonlinearities cancellation to guarantee the aircraft attitude stability and to propose a robust control structure in discrete-time, considering all uncertainties. Various simulation studies have been carried out to illustrate the robustness and effectiveness of the proposed controller structure.

Nonlinear coordinated control design of generator excitation and static var compensator for power system via input-output linearization

This paper proposes a nonlinear coordinated controller for a single machine infinite bus power system. The later consists of a synchronous generator connected to the infinite bus via transmission lines, which are equipped with a static var compensator. The proposed control strategy aims to control simultaneously the excitation system of the synchronous generator and the static var compensator in order to improve transient stability and voltage regulation. The input output linearization theory and pole-assignment technique are employed to design the nonlinear controller. The controller’s performance in single machine infinite bus power system is then examined using simulation studies when the studied power system is subjected to three-phase short circuit with a 100ms duration. The results validate the efficiency of the proposed controller, which is based mainly on the good regulation of the static var compensator voltage with removing the static error after fault elimination.

Input–output linearization of non-linear time-varying delay systems: the single-input single-output case

This paper deals with the input–output linearization of non-linear time-varying delay systems. We introduce an extension of the Lie derivative for time-varying delay systems and derive sufficient conditions for the existence of a causal and bounded non-linear feedback linearizing the input–output behaviour of the system. Sufficient conditions ensuring the internal stability after output stabilization are also presented. Finally, several examples illustrating our main results are discussed.