CACACE , Filippo

This paper investigates the control problem of linear systems affected by an unknown constant input delay by means of a finite-dimensional state feedback. The proposed solution extends an approach used in the case of known delays by means of a suitably developed delay identifier. A more general result about the convergence to zero of the...

We consider the filtering problem of LTI continuous-time systems with known and bounded measurement delays. The aim of the technical note is the design of a finite-dimensional sub-optimal filter whose performance in terms of the estimation error is comparable to optimal infinite-dimensional approaches. We show that the proposed approach allows...

This note studies the LQ and LQG problems for linear time invariant systems with a single time-varying input delay and instantaneous (memoryless) state feedback. We extend the memoryless state feedback solution proposed in [1] in two directions. We prove that in the deterministic case a memoryless state feedback can be in general optimal only...

This paper introduces a new filter for linear continuous-time stochastic systems with delayed measurements. The approach is inspired by an observer designed for deterministic systems. The obtained solution is suboptimal and does not use distributed integration terms with advantages in terms of computational load. The relationship between the...

The class of strict-feedback systems enjoys special properties that make it similar to linear systems. This paper proves that such a class is equivalent, under a change of coordinates, to the wider class of feedback linearisable systems with multiplicative input, when the multiplicative terms are functions of the measured variables only. We...

This paper studies the problem of recursive state estimation of stochastic linear systems with nonlinear measurements. The main idea is to rewrite the measurement map in a linear form by considering, as system output, a vector of "virtual" measurements. The result is a linear system with a non-Gaussian and nonstationary output noise. State...

This paper concerns the state estimation problem for linear discrete-time systems with non-Gaussian state and output noises. A sub-optimal quadratic filter algorithm is proposed. In order to enlarge the class of systems allowed to be processed, a novel approach based on the output injection stabilization is derived. Also a second benefit to the...

In this paper, we consider the control problem of strict-feedback nonlinear systems with time-varying input and output delays. The approach is based on the usual observer/predictor/feedback approach, but the novelty is the use of the closed-loop dynamics in the predictor. This approach allows to develop two designs, an instantaneous predictor...

This paper proposes a new method to simultaneously estimate the state and the delay of a linear time delay system. The approach is based on the definition of an augmented linear time-varying model whose state is composed by both the original state vector and the delay. The estimation is then carried out by developing an appropriate observer for...

This paper concerns with the state estimation problem of nonlinear systems with sampled noisy measurements. The main idea is to exploit a result of the analysis of nonlinear systems, which considers a class of state-space nonlinear models admitting the design of a deterministic observer with linear error dynamics. Such systems are supposed to...

The problem of state estimation for nonlinear systems with unknown state delays is still an open problem. In this paper, we propose to add a delay identifier to suitable high-gain observers in order to achieve simultaneous estimation of state and delay. In the case of one constant delay in the state, we provide sufficient conditions to...

This paper proposes an optimal control law for linear systems affected by input delays. Specifically we prove that when the delay functions are known it is possible to generate the optimal control for arbitrarily large delay values by using a DDE without distributed terms. The solution can be seen as a chain of predictors whose size depends on...

This paper concerns the state estimation problem for linear discrete-time non-Gaussian systems. It is known that filters based on quadratic functions of the measurements processes (Quadratic Filter) improve the estimation accuracy of the optimal linear filter. In order to enlarge the class of systems, which can be processed by a Quadratic...

The problem of state estimation for nonlinear systems with unknown state or measurement delays is still an open problem. In this paper, we consider the case of measurement delay and propose an approach that combines a delay identifier with a suitable high-gain observer in order to achieve simultaneous estimation of state and delay. We provide...

This paper deals with the optimal filtering and optimal output-feedback control of discrete-time, linear time-varying non-Gaussian systems. In the hypothesis that the time-varying and non-Gaussian distributions of the state and measurement noises have bounded and known moments up to a given order, this work extends previous results about...

This paper proposes an alternative theory to the Ito calculus due to Balakrishnan: the white noise theory in Hilbert spaces. The proposed approach extends Blakrishnan's theory to a new class of nonlinear systems. The method uses the theory of differential geometry to devise a suitable map which transforms the starting system in an equivalent...

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