171,243 research outputs found
Profilazione e trattamento dei dati personali, in L. CALIFANO e C. COLAPIETRO (a cura di), Innovazione tecnologica e valore della persona. Il diritto alla protezione dei dati personali nel Regolamento UE 2016/679
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Il Regolamento UE 2016/679 e la costruzione di un modello uniforme di diritto europeo alla riservatezza e alla protezione dati personali
No full textRepetitive Control Meets Continuous Zero Phase Error Tracking Controller for Precise Tracking of B-Spline Trajectories
No full textIn this paper, a novel repetitive control scheme is presented and discussed, based on the so-called B-spline filters. These dynamic filters are able to generate a B-spline trajectory if they are fed with the sequence of control points defining the curve. Therefore, they are ideal tools for generating online reference signals with the prescribed level of smoothness for driving dynamic systems, possibly together with a feedforward compensator. In particular, a continuous zero phase error tracking controller (ZPETC) can be used for tracking control of nonminimum phase systems but because of its open-loop nature it cannot guarantee the robustness with respect to modeling errors and exogenous disturbances. For this reason, ZPETC and trajectory generator have been embedded in a repetitive control scheme that allows to nullify interpolation errors even in nonideal conditions, provided that the desired reference trajectory and the disturbances are periodic. This paper is based on the results presented in the conference paper [L. Biagiotti, F. Califano, and C. Melchiorri, 'Repetitive control of non-minimum phase systems along b-spline trajectories,' in Proc. IEEE 55th Conf. Decis. Control, 2016, pp. 5496-5501.], where asymptotic stability of the overall control scheme has been proved mathematically, but extends such results with an experimental validation based on a nonminimum phase system. Different models of the same physical system have been identified and used in the implementation of this model-based control scheme, allowing a real evaluation of the relationship between control system performance and model accuracy
Observability of nonlinear time–delay systems and its application to their state realization
No full textIn this paper, it is shown that the two notions of weak observability and strong observability may not be sufficient to describe the link between the input/output equation associated to the behaviour of a system and its state space realization. A new notion, called regular observability, is introduced, which is shown to capture essential features of nonlinear time delay systems and the existence of some realization
T-accessibility for Nonlinear Time-Delay Systems: The general case
No full textFollowing the results recently obtained for nonlinear driftless systems affected by constant commensurate delays, a partial characterization of t - accessibility is provided for general nonlinear time-delay systems affected by constant commensurate delays. Conditions are given for this new property. The results are stated using the differential representation of time-delay systems
Feedback linearization of nonlinear time-delay systems over a time window via discontinuous control
No full textFeedback linearization is worked out for nonlinear time-delay systems and it is shown that even if the problem can not be solved for all time, it may still be solved over some time windows. The solution then reduces to a discontinuous state feedback. It is foreseen that such piecewise feedback linearization can be instrumental for stabilization by a discontinuous control, although it is not the scope of this paper. The approach used herein may be used to address other classical control problems. It takes advantage of the delays as delays duplicate somehow the number of independent control values at some given time instant
T-Accessibility for a class of nonlinear time–delay systems
No full textObservability and detectability on one hand as well as accessibility and controllability on the other, are related properties and have not been closely investigated for nonlinear–time delay systems until these recent years. Currently accessibility or nonlinear time delay systems is defined as the absence of autonomous functions on the extended state space. Such a property is expressed in terms of the Accessibility matrix rank, extending to the nonlinear context the well known Kalman Criterion. A weaker notion is introduced in this paper which is motivated by the fact that even if autonomous functions exist for the given system, it may be still possible to move from a fixed point to an arbitrary one in some open subset of IRn. The study is performed on the class of driftless single input system
Nonlinear energy cascade in nonuniform media
No full textThe nonlinear energy cascade in a nonuniform magnetized plasma is studied by using a simple model allowing an analytical solution. The results are then confirmed by a more refined numerical investigation. It is shown that the propagation of moderate amplitude Alfven waves interacting with the background may result in the dissipation of the equilibrium energy much faster than its standard resistive timescale
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