Dynamic surface control (DSC) method uses high gain filters to avoid the ”explosion of complexity” issue inherent in backstepping based controller designs. As a result, the closed loop system and filter dynamics possess time scale separation between them. This paper attempts to design a novel disturbance observer based dynamic surface controller using contraction framework. In doing so the stea...

This paper focuses on the observer-based passive fuzzy controller design problem for uncertain Takagi-Sugeno (T-S) fuzzy models with time-delay and multiplicative noise. For stability analysis and synthesis, the sufficient conditions are derived via Lyapunov-krasovskii function and Itô’s formula in terms of Linear Matrix Inequalities (LMIs). In addition, the passivity theory is employed to disc...

Observer based controllers for loop transfer recovery of non-strictly proper systems which are left invertible and of minimum phase are considered. A complete analysis of loop transfer recovery problem using either full or reduced order observer based controller is provided. Key Words-Robust control, loop transfer recovery.

This paper advocates disturbance observer based control (DOBC) for uncertain nonlinear systems. Within this framework, a nonlinear controller is designed based on the nominal model in the absence of disturbance and uncertainty where the main design specifications are to stabilize the system and achieve good tracking performance. Then a nonlinear disturbance observer is designed to not only esti...

This paper addresses the problem of stabilizing a nonlinear system by means of quantized output feedback. A conceptual framework is presented in which the control input is generated by an observer-based feedback controller acting on quantized output measurements. A stabilization result is established under the assumption that this observer-based controller possesses robustness with respect to o...

We propose a global high-gain scaling based observer/controller for systems in the uncertain generalized output-feedback canonical form. Time-varying nonlinear parametric uncertainty is allowed to occur coupled with unmeasured states in the system dynamics. This represents a significant generalization from existing results which allow unknown parameters only in outputdependent terms. This restr...

A multiple model based observer/estimator for the estimation of parameters is used to reset the parameter estimation in a conventional Lyapunov based nonlinear adaptive controller. The advantage of combining both approaches is that the performance of the controller with respect to disturbances can be considerably improved while a reduced controller gain will increase the robustness of the appro...