In this article, the cascade connection of two “buck” converters is examined from the perspective of differential flatness and Generalized Proportional Integral (GPI) observer–based control. The multi-variable nonlinear “buckbuck” converter is subject to unknown, time-varying, load current demands, at each one of the outputs of the two constitutive stages. The linear output feedback controllers...

This paper considers the problem of delay-dependent robust stability for uncertain systems with interval time-varying delays. By using the direct Lyapunov method, a new Lyapunov-Krasovskii (L-K) functional is introduced based on decomposition approach, when dealing with the time derivative of L-K functional, a new tight integral inequality is adopted for bounding the cross terms. Then, a new le...

This paper investigates the chaos synchronization problem for a class of uncertain master–slave unified chaotic systems. Based on the sliding mode control technique, a robust control scheme is established which guarantees the occurrence of a sliding motion of error states even when the parameter uncertainty and external perturbation are present. Furthermore, a novel proportional–integral (PI) s...

The robust L2-gain estimation is investigated for general uncertain systems with structured uncertainties. A new estimation structure is introduced: the Augmented-Gain Observer which encompasses both filters and observers and allows robust estimation even for some classes of unstable systems. Our approach is based on a separation of graphs theorem using frequency dependent Integral Quadratic Co...

This paper presents a new supervisory control scheme, which is based on a control-relevant switching logic. Unlike most of the existing switching methods considering only estimator performance, the proposed scheme takes both estimator and controller performance into account. As an index to the controller performance, an iISS (integral-Input-to-State Stability) Lyapunov function is employed; it ...

Motion control and robust path tracking were the subject of this paper. A method based on fractional prefilter which is extended to multivariable systems is developed. This approach is based on the MIMO-QFT robust synthesis methodology combined with CRONE control. This paper incorporates Quantitative Feedback Theory (QFT) principles to CRONE control design procedure to solve the Two-Degree-Of-F...

The problem of delay-dependent robust H∞ control for uncertain singular systems with time-varying delay is addressed in this paper. The uncertainty is assumed to be norm bounded. By establishing an integral inequality based on quadratic terms, a new delay-dependent bounded real lemma is derived and expressed in terms of linear matrix inequality(LMI). A suitable robust H∞ state feedback control ...

This paper is concerned with existence and optimality properties of so-called guaranteed cost controllers for an uncertain system subject to structured uncertainty. The uncertainty in the system is assumed to have a stochastic character and to satisfy certain stochastic integral constraints. It is shown that a minimax optimal guaranteed cost state feedback controller for a stochastic system can...

H ∞ control problem using a stable nonlinear output feedback controller is presented in this paper. The particular class of nonlinear uncertain systems being considered is characterized in terms of Integral Quadratic Constraints and Global Lipschitz Conditions describing the admissible uncertainty and nonlinearity, respectively. The nonlinear controller is then constructed by including a copy o...

As stated by Johnson [Joh04], the visualization of uncertainty remains one of the major challenges for the visualization community. To achieve this, we need to understand and develop methods that allow us not only to consider uncertainty as an extra variable within the visualization process, but to treat it as an integral part. In this paper, we take contouring, one of the most widely used visu...