This paper studies output feedback control of pure-feedback systems with immeasurable states and completely non-affine property. Since availability of all the states is usually impossible in the actual process, we assume that just the system output is measurable and the system states are not available. First, to estimate the immeasurable states a state observer is designed. Relatively fewer res...

Generic results regarding the structural properties of LTI singular system are presented in this paper. These include the structure of the system poles (both finite and infinite), assignment of the finite poles, elimination of the impulse mode, and controllability and observability of the closed-loop system. These properties are characterized by some new concepts defined in this paper.

Singular perturbation problems have been studied by many mathematicians. Since the approximate solutions of these problems are as the sum of internal solution (boundary layer area) and external ones, the formation or non-formation of boundary layers should be specified. This paper, investigates this issue for a singular perturbation problem including a first order differential equation with gen...

A singularly perturbed model is proposed for a system comprised of a PEM Fuel Cell(PEM-FC) with Natural Gas Hydrogen Reformer (NG-HR). This eighteenth order system is decomposedinto slow and fast lower order subsystems using singular perturbation techniques that provides tools forseparation and order reduction. Then, three different types of controllers, namely an optimal full-order,a near-opti...

H altitude or impulse response matrix I identity matrix j dummy index M Mach number R correlation coefficient S matrix of singular values STBL left stabiliser position STBR right stabiliser position t, Δt time, time step T projected state matrix multiplied by the instrument TEFL left trailing-edge flap deflection TEFR right trailing-edge flap deflection u system input vector U matrix of past or...

Implicit time stepping procedures for the time dependent Stokes problem lead to stationary singular perturbation problems at each time step. These singular perturbation problems are systems of saddle point type, which formally approach a mixed formulation of the Poisson equation as the time step tends to zero. Preconditioners for discrete analogous of these systems are discussed. The preconditi...

The question how the classical definition of the Smith zeros of an LTI continuous-time singular control system S(E, A, B, C, D) can be generalized and related to state-space methods is discussed. The zeros are defined as those complex numbers for which there exists a zero direction with a nonzero state-zero direction. Such a definition allows an infinite number of zeros (then the system is call...

We study the stability characteristic of the active disturbance rejection control for a nonlinear, time-varying plant. To this end, the closed-loop system is reformulated in a form that allows the singular perturbation method to be applied. Since singular perturbation approach enables the decomposition of the original system into a relatively slow subsystem and a relatively fast subsystem, the ...