Tomás Vyhlídal

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An eigenvalue based approach for the stabilization of linear neutral functional differential equations is presented, which extends the recently developed continuous pole placement method for delay equations of retarded type. The approach consists of two steps. First the stability of the associated difference equation is determined and a procedure is applied(More)
The paper deals with a novel method of control system design which applies meromorphic transfer functions as models for retarded linear time delay systems. After introducing an auxiliary state model a finite-spectrum observer is designed to close a stabilizing state feedback. The observer finite spectrum is the key to implement a state feedback(More)
A novel method for the determination of controller parameters in a broad class of linear control systems affected by time-delays is presented. This method is based on an appropriate shaping of the spectrum of the closed-loop system. Its application follows two steps. First, a number of rightmost poles, smaller than the number of controller parameters, are(More)
The paper presents an optimization-based algorithm for stabilizing retarded systems using a statederivative feedback controller. It is shown that an application of such a controller results in neutral dynamics of the closed-loop system if small feedback delays occur. Therefore, the strong stability theory of neutral systems needs to be considered in the(More)
The stability theory for linear neutral equations subjected to delay perturbations is addressed. It is assumed that the delays cannot necessarily vary independently of each other, but depend on a possibly smaller number of independent parameters. As a main result necessary and sufficient conditions for strong stability are derived along with bounds on the(More)
We study the stabilizability of a linear controllable system using state derivative feedback control. As a special feature the stabilized system may be fragile, in the sense that arbitrarily small modelling and implementation errors may destroy the asymptotic stability. First, we discuss the pole placement problem and illustrate the fragility of stability(More)
We follow a polynomial approach to analyse strong stability of linear difference equations with rationally independent delays. Upon application of the Hermite stability criterion on the discrete-time homogeneous characteristic polynomial, assessing strong stability amounts to deciding positive definiteness of a multivariate trigonometric polynomial matrix.(More)
Besides its original use in the state space based design the pole assignment is also applied in tuning the PID controllers where only an approximate model is considered. However, the common assumption of time delay in this model imposes the limitation that only such pole prescription which results in the dominant pole assignment can be effective in tuning(More)