Christina Kazantzidou

On the computation of the fundamental subspaces for descriptor systems

ABSTRACT In this paper, we investigate several theoretical and computational aspects of fundamental subspaces for linear time-invariant descriptor systems, which appear in the solution of many control and estimation problems. Different types of reachability and controllability for descriptor systems are described and discussed. The Rosenbrock system matrix pencil is employed for the computation of supremal output-nulling subspaces and supremal output-nulling reachability subspaces for descriptor systems.

Denominator Assignment, Invariants and Canonical Forms Under Dynamic Feedback Compensation in Linear Multivariable Systems

A result originally reported in [3] for linear time invariant single input-single output systems and concerning an invariant and a canonical form of the transfer function matrix of the closed loop system under dynamic feedback compensation is generalized for LTI multivariable systems. This result leads to a characterization of the class of closed loop transfer function matrices which are obtainable under feedback through a proper dynamic compensator and gives rise to an algorithmic design procedure for the computation of a proper dynamic (feedback), internally stabilizing and denominator assigning compensator for non-minimum phase plants.

Nonovershooting state feedback and dynamic output feedback tracking controllers for descriptor systems

ABSTRACT The use of linear multivariable feedback control to achieve a nonovershooting step response is considered for multi-input multi-output (MIMO) linear time-invariant (LTI) descriptor systems. The use of dynamic output feedback control to improve the transient response to a step input is also considered for MIMO and LTI descriptor systems. We design a state feedback controller and a dynamic output feedback for MIMO and LTI descriptor systems to asymptotically stabilise and track a step reference with zero overshoot and arbitrarily small rise time, under some mild assumptions.

Relations between denominator assigning proper feedback compensators and pole assignment by state feedback

We examine relations between denominator assigning proper compensators in the feedback path of linear, time invariant (LTI) multivariable systems, described by square strictly proper transfer function matrices, and pole assignment by state variable feedback. Through these results we establish conditions for the existence and computation of such compensators.

Denominator assignment, invariants and canonical forms under dynamic feedback compensation in linear multivariable systems

A result originally reported in [3] for linear time invariant single input-single output systems and concerning an invariant and a canonical form of the transfer function matrix of the closed loop system under dynamic feedback compensation is generalized for LTI multivariable systems. This result leads to a characterization of the class of closed loop transfer function matrices which are obtainable under feedback through a proper dynamic compensator and gives rise to an algorithmic design procedure for the computation of a proper dynamic (feedback), internally stabilizing and denominator assigning compensator for non-minimum phase plants.