Fractional robust control of ligthly damped systems

The article proposes a method to design a robust controller ensuring the damping ratio of a closed-loop control. The method uses a contour para-meterized by the damping ratio in the Nichols plane and the complex non-integer (or fractional)differentiation to compute a transfer function whose open-loop Nichols locus tangents this contour, thus ensuring dynamic performance. The proposed method is applied to a flexible structure (a clamped-free beam with piezoelectric ceramics). The aims of the control loop are to decrease the vibrations and to ensure the damping ratio of the controlled system

Fractional robust control with iso-damping property

This article deals with the problem of the reduction of structural vibrations with isodamping property. The proposed methodology is based on: - a contour defined in the Nichols plane and significant of the damping ratio of the closed-loop response - a robust control method that uses fractional order integration. The methodology is applied to an aircraft wing model made with a beam and a tank whose different levels of fillings are considered as uncertainties

Fractional active robust control

This article deals with the reduction of structural vibrations. Two approaches are possible to tackle this problem, either a passive method with dampers, or an active method with actuators that are controlled in order to decrease or even cancel the vibrations in the structure. The second method is used here. The objective is to control the damping of uncertain plants. The proposed methodology is based on iso-damping contours and CRONE control. The iso-damping contours are defined thanks to fractional order integration in the Nichols plane and are graduated by the value of the damping factor of the closed-loop response. The CRONE control is a robust control method that also uses fractional order integration. The methodology is here applied to a multivariable plant that is an aircraft wing model made with a beam and a tank whose different levels of fillings are considered as uncertainties

CRONE control of the elevation of a helicopter model

This article presents an application of the CRONE control to a helicopter model. The model is non linear and the non linearity is considered as uncertainty. First an accurate model of the helicopter is established. The CRONE methodology is then described step by step and applied to the helicopter model. The obtained controller is tested in simulation and on the real system, even in presence of perturbation