Ricerc@Sapienza

This paper proposes the use of a novel nonsingular Terminal Sliding surface for the finite-time robust stabilization of second order nonlinear plants with matched uncertainties. Mathematical characteristics of the proposed surface are such that a fixed bound naturally exists for the settling time of the state variable, once the surface has been reached. A simple redesign of the control input able to ensure the feature of fixed-time reaching of the sliding surface will be also presented, and fixed-time stability will be guaranteed by the proposed Terminal Sliding Mode Control design method.

In this work, the notion of reduction is introduced for discrete-time nonlinear input-delayed systems. The retarded dynamics is reduced to a new system which is free of delays and equivalent (in terms of stabilizability) to the original one. Different stabilizing strategies are proposed over the reduced model. Connections with existing predictor-based methods are discussed. The methodology is also worked out over particular classes of time-delay systems as sampled-data dynamics affected by an entire input delay.

The paper deals with stabilization of feedforwardmultiple cascade dynamics under sampling. It is shown that u-average passivity concepts and Lyapunov methods can be profitably exploited to provide a systematic sampled-data design procedure. The proposed methodology recalls the continuous-time feedforwarding steps and can be applied under the same assumptions as those set over the continuous-time cascade dynamics. The final sampled feedback is carried out through a three steps procedure that involves iterative passivation and stabilization in the u-average sense.

In this work, how sampling can be instrumental for stabilizing nonlinear dynamics with delays is discussed through several approaches developed by the authors in a comparative perspective with respect to the existing literature. Performances and computational aspects are illustrated through academic examples.

The paper addresses the problem of an observer design for a nonlinear system for which a linear approach is followed for the control synthesis. The linear context driven by the control design allows to focus the observers design in the class of local, i.e. linear, observers. It is shown that when the control contains an external reference, the solution obtained working with the linear approximation to get local solutions produces non consistent results in terms of local regions of convergence for the system and for the observer.

This contribution aims at making an overview of the most recent activities/contributions in education in the control field by members of the Technical Committee Nonlinear Systems, in order to share the best practices and ideas in the community, as well as to investigate into the level of awareness, interest and involvement of the TC members in several aspects concerning education. (C) 2019, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.

In a classical distributed framework, we present a novel distributed observer for genuinely nonlinear
continuous-time plants. A network of sensors monitors a multiple-outputs plant. Each sensor measures
only a portion of the plant’s outputs, and the sensing capability is different from sensor to sensor.
The assumption of strongly connected digraph on the underlying sensor network ensures robustness
and direct communication paths between nodes. Moreover, incremental homogeneity assumptions