http://195.251.240.227/jspui/handle/123456789/216 2026-05-30T00:47:50Z 2026-05-30T00:47:50Z Ιακωβίδου, Ιωάννα http://195.251.240.227/jspui/handle/123456789/14804 2022-06-22T12:56:40Z

Title: Μη επανδρωμένα οχήματα ξενάγησης Authors: Ιακωβίδου, Ιωάννα Description: Πτυχιακή εργασία - Σχολή Τεχνολογικών Εφαρμογών - Τμήμα Μηχανικών Αυτοματισμού, 2019 (α/α 11439)

Stergiopoulos, Fotis Yfoulis, Christos Giaouris, Damian Papadopoulou, Simira Ziogou, Chrysovalantou Voutetakis, Spyros http://195.251.240.227/jspui/handle/123456789/10009 2018-02-28T16:10:13Z 2014-06-16T00:00:00Z

Title: Flexible polyhedral Lyapunov functions for the robust constrained stabilization of bilinear boost DC-DC converters Authors: Stergiopoulos, Fotis; Yfoulis, Christos; Giaouris, Damian; Papadopoulou, Simira; Ziogou, Chrysovalantou; Voutetakis, Spyros Abstract: Recent research efforts, relying on constrained stabilization principles, have been concentrated on the design of robust and efficient state-feedback control laws for switched-mode DC-DC boost converters, characterized by accurate nonlinear dynamics incorporation, nonconservative handling of hard state and control constraints, and robustness to supply voltage variations and load changes. This paper focuses on the efficient construction of flexible polyhedral Lyapunov functions, which can facilitate control design procedures which address all aforementioned issues via the generation of contractive polytopes (safety domains). New non-conservative conditions for the averaged-model bilinear converter dynamics and a corresponding ray-gridding algorithm are proposed that allow near-maximal approximations of the real stability domains with negligible computational cost. A significant improvement in the size of the contractive domains is obtained by resorting to more flexible partial contractivity conditions. This novelty allows the extension of the constrained stabilization framework to robust constrained tracking, whereby a wide operating region may be covered. The proposed ideas can be applied for the specification of affine state-feedback control laws and are numerically evaluated on a boost converter example using the exact switched model of the converter. Description: Δημοσιεύσεις μελών--ΣΤΕΦ--Τμήμα Αυτοματισμού, 2015

2014-06-16T00:00:00Z Ziogou, Chrysovalantou Voutetakis, Spyros Papadopoulou, Simira Yfoulis, Christos Stergiopoulos, Fotis Giaouris, Damian http://195.251.240.227/jspui/handle/123456789/10003 2018-02-28T16:10:12Z 2015-07-15T10:48:50Z

Title: Border Collisions and Chattering in State Feedback Controlled Boost Converters Authors: Ziogou, Chrysovalantou; Voutetakis, Spyros; Papadopoulou, Simira; Yfoulis, Christos; Stergiopoulos, Fotis; Giaouris, Damian Abstract: Digital state feedback controllers are frequently used in DC-DC converters when high/optimal performance is required. In this paper we investigate the nonlinear behavior of such systems when the feedback control law is a discontinuous function of the location of the state vector in the state space. It is shown that the well known problem of chattering that appears in these controllers (e.g. in Model Predictive Control - MPC) is due to a border collision between the fixed point of the nominal period one orbit and the borders that define the areas that the specific gains are utilized, and forces the converter to exhibit high current ripple that can deteriorate the system’s performance. The exact switched dynamical model of the system is described along with the three switching manifolds in the state space and through that a detailed analysis of the border collision that causes the chattering and the high current ripple is presented. Finally, a methodology is proposed that can lead to a design procedure that completely avoids this problem. The latter can be taken into account when advanced controllers are employed in order to guarantee the optimal behavior of the system. Description: Δημοσιεύσεις μελών--ΣΤΕΦ--Τμήμα Αυτοματισμού, 2015

2015-07-15T10:48:50Z Papadopoulou, Simira Voutetakis, Spyros Seferlis, Panos Stergiopoulos, Fotis Yfoulis, Christos Giaouris, Damian Ziogou, Chrysovalantou http://195.251.240.227/jspui/handle/123456789/10007 2018-02-28T16:10:12Z 2015-07-15T10:18:55Z

Title: Supervisory Energy Management of an Integrated Fuel Cell / Battery System for Vehicular Applications Authors: Papadopoulou, Simira; Voutetakis, Spyros; Seferlis, Panos; Stergiopoulos, Fotis; Yfoulis, Christos; Giaouris, Damian; Ziogou, Chrysovalantou Abstract: This work presents an energy management strategy (EMS) for an integrated fuel cell and battery system for vehicular applications. A challenging issue when integrating fuel cells to such applications is the handling of the dynamics that arise by their use. Additionally when a fuel cell is combined with a battery then various decisions should be made in order for the integrated system to operate in an optimum way, while fulfilling the frequently and rapidly changing load demand. In that context the resulting hybrid system should be complemented by a control system that will be able to handle the complex dynamics and the discrete decisions of the overall system. At the core of the considered control system an EMS is developed that dictates the appropriate decisions for each subsystem at various operating conditions. The goal of this work is to explore the behavior of the hybrid system under a realistic operation scenario which will be controlled by an EMS that relies on a Hybrid Timed Automaton (HTA). Besides the fulfillment of the load demand, the objectives of the EMS include the optimal use of the available hydrogen, the protection of the battery’s lifetime and the preservation of the fuel cell’s durability. Description: Δημοσιεύσεις μελών--ΣΤΕΦ--Τμήμα Αυτοματισμού, 2015

2015-07-15T10:18:55Z