Decoupling in singular systems: a polynomial equation approach
Design of observer based compensators: The polynomial approach
Differential flatness and defect: an overview
We introduce flat systems, which are equivalent to linear ones via a special type of feedback called endogenous. Their physical properties are subsumed by a linearizing output and they might be regarded as providing another nonlinear extension of Kalman's controllability. The distance to flatness is measured by a non-negative integer, the defect. We utilize differential algebra which suits well to the fact that, in accordance with Willems' standpoint, flatness and defect are best defined without...
Discrete-time control systems on homogeneous spaces: partition property
Disturbance rejection by proportional and derivative output feedback
Eigenvalue assignment via state observer for descriptor systems
Equivalence of control systems with linear systems on Lie groups and homogeneous spaces
The aim of this paper is to prove that a control affine system on a manifold is equivalent by diffeomorphism to a linear system on a Lie group or a homogeneous space if and only if the vector fields of the system are complete and generate a finite dimensional Lie algebra. A vector field on a connected Lie group is linear if its flow is a one parameter group of automorphisms. An affine vector field is obtained by adding a left invariant one. Its projection on a homogeneous space, whenever it exists,...
Errata corrige: “The matching problem for behavioral systems”
Estimation for linear pure delay time systems
Estimation of polynomial roots by continued fractions
Evaluation of the reachability subspace of general form polynomial matrix descriptions (PMDs)
Exact controllability of linear dynamical systems: A geometrical approach
In recent years there has been growing interest in the descriptive analysis of complex systems, permeating many aspects of daily life, obtaining considerable advances in the description of their structural and dynamical properties. However, much less effort has been devoted to studying the controllability of the dynamics taking place on them. Concretely, for complex systems it is of interest to study the exact controllability; this measure is defined as the minimum set of controls that are needed...
Exact modelling of scalar 2D arrays
Extended lie algebraic stability analysis for switched systems with continuous-time and discrete-time subsystems
We analyze stability for switched systems which are composed of both continuous-time and discrete-time subsystems. By considering a Lie algebra generated by all subsystem matrices, we show that if all subsystems are Hurwitz/Schur stable and this Lie algebra is solvable, then there is a common quadratic Lyapunov function for all subsystems and thus the switched system is exponentially stable under arbitrary switching. When not all subsystems are stable and the same Lie algebra is solvable, we show...
Exterior algebra and invariant spaces of implicit systems: The Grassmann representative approach
Falseness of the finiteness property of the spectral subradius
We prove that there exist infinitely may values of the real parameter α for which the exact value of the spectral subradius of the set of two matrices (one matrix with ones above and on the diagonal and zeros elsewhere, and one matrix with α below and on the diagonal and zeros elsewhere, both matrices having two rows and two columns) cannot be calculated in a finite number of steps. Our proof uses only elementary facts from the theory of formal languages and from linear algebra, but it is not constructive...
Feedback canonical forms of singular systems
Finite-dimensionality of information states in optimal control of stochastic systems: a Lie algebraic approach
In this paper we introduce the sufficient statistic algebra which is responsible for propagating the sufficient statistic, or information state, in the optimal control of stochastic systems. Certain Lie algebraic methods widely used in nonlinear control theory, are then employed to derive finite- dimensional controllers. The sufficient statistic algebra enables us to determine a priori whether there exist finite-dimensional controllers; it also enables us to classify all finite-dimensional controllers....
Fractional hold circuits versus positive realness of discrete transfer functions.