Abstract: In this paper, we consider the problems of approximating uncertainties and feedback control for a class of nonlinear systems without full-known states, and two approximation methods are proposed: universal approximation using integral-chain differentiator or extended observer. Comparing to the approximations by fuzzy system and radial-based-function (RBF) neural networks, the presente...

Fractional order derivative is one of the important techniques for the designing of fractional order filter such as differentiator and integrator. Three basic approaches that are used for the design of the fractional order differentiator namely: discretization method, interpolation method and approximation method. All these method provide a great degree of approximation to the designed filter s...

A novel decentralized output-feedback controller is proposed in this paper for large-scale uncertain general nonautonomous nonlinear systems without prior knowledge of the input gain’s sign. The subsystems are considered to be completely unknown and nonautonomous, except their known full relative degree. uses a higher-order switching differentiator estimate time-derivatives output tracking erro...

The availability of an optical connection is considered to be a critical service differentiator in WDM optical networks. In this regard, the design of a protection scheme that improves the availability of high priority optical connections and makes efficient use of optical resources is a major challenge faced by optical network operators. In a previous study, we proposed the so-called priority-...

This article develops a new output feedback tracking control scheme for uncertain robot manipulators with only position measurements. Unlike the conventional sliding mode controller, a quasi-continuous second-order sliding mode controller (QC2C) is first designed. Although the QC2C produces continuous control and less chattering than conventional sliding mode and other high-order sliding mode c...

In this paper, two new versions of modified active disturbance rejection control (MADRC) are proposed to stabilize a nonlinear quadruple tank system and the water levels lower tanks in presence exogenous disturbances, parameter uncertainties, parallel varying input set-points. The first scheme is configured from combination tracking differentiator (TD), super twisting sliding mode (STC-SM), ext...