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Mixed H2/H∞ filtering for uncertain systems with regional pole assignment
Copyright [2005] IEEE. This material is posted here with permission of the IEEE. Such permission of the IEEE does not in any way imply IEEE endorsement of any of Brunel University's products or services. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to [email protected]. By choosing to view this document, you agree to all provisions of the copyright laws protecting it.The mixed H2/H∞ filtering problem for uncertain linear continuous-time systems with regional pole assignment is considered. The purpose of the problem is to design an uncertainty-independent filter such that, for all admissible parameter uncertainties, the following filtering requirements are simultaneously satisfied: 1) the filtering process is asymptotically stable; 2) the poles of the filtering matrix are located inside a prescribed region that compasses the vertical strips, horizontal strips, disks, or conic sectors; 3) both the H2 norm and the H∞ norm on the respective transfer functions are not more than the specified upper bound constraints. We establish a general framework to solve the addressed multiobjective filtering problem completely. In particular, we derive necessary and sufficient conditions for the solvability of the problem in terms of a set of feasible linear matrix inequalities (LMIs). An illustrative example is given to illustrate the design procedures and performances of the proposed method
Note on massless bosonic states in two-dimensional field theories
In a wide class of invariant two-dimensional
super-renormalizable field theories, the parity-odd part of the two-point
function of global currents is completely determined by a fermion one-loop
diagram. For any non-trivial fermion content, the two-point function possesses
a massless pole which corresponds to massless bosonic physical states. As an
application, we show that two-dimensional supersymmetric
gauge theory without a superpotential possesses symmetry
and contains one massless bosonic state per fixed spatial momentum. The
supersymmetric pure Yang-Mills theory possesses
symmetry, and there exist at least three massless
bosonic states.Comment: 17pages, 4 figures, uses PTPTeX.cls and feynMF, added an appendi
Environmental test chamber for the support of learning and teaching in intelligent control
The paper describes the utility of a low cost, 1 m2 by 2 m forced ventilation, micro-climate test chamber, for the support of research and teaching in mechatronics. Initially developed for the evaluation of a new ventilation rate controller, the fully instrumented chamber now provides numerous learning opportunities and individual projects for both undergraduate and postgraduate research students
Unitarity constraints on chiral perturbative amplitudes
Low lying scalar resonances emerge as a necessary part to adjust chiral
perturbation theory to experimental data once unitarity constraint is taken
into consideration. I review recent progress made in this direction in a model
independent approach. Also I briefly review studies on the odd physical
properties of these low lying scalar resonances, including in the
processes.Comment: Talk given at: International Workshop on Effective Field Theories:
from the pion to the upsilon, February 2-6 2009, Valencia, Spai
Multi-Objective Robust H-infinity Control of Spacecraft Rendezvous
Based on the relative motion dynamic model illustrated by C-W equations, the problem of robust Hinfin control for a class of spacecraft rendezvous systems is investigated, which contains parametric uncertainties, external disturbances and input constraints. An Hinfin state-feedback controller is designed via a Lyapunov approach, which guarantees the closed-loop system to meet the multi-objective design requirements. The existence conditions for admissible controllers are formulated in the form of linear matrix inequalities (LMIs), and the controller design is cast into a convex optimization problem subject to LMI constraints. An illustrative example is provided to show the effectiveness of the proposed control design method
Robust scheduled control of longitudinal flight with handling quality satisfaction
Classic flight control systems are still widely used in the industry because of acquired experience and good understanding of their structure. Nevertheless, with more stringent constraints, it becomes difficult to easily fulfil all the criteria with these classic control laws.
On the other hand, modern methods can handle many constraints but fail to produce low order controllers. The following methodology proposed in this paper addresses both classic and modern flight control issues, to offer a solution that leverages the strengths of both approaches. First, an H∞ synthesis is performed in order to get controllers which satisfy handling qualities and are robust withrespect to mass and centre of gravity variations. These controllers are then reduced and structured by using robust modal control techniques. In conclusion, a self-scheduling technique is described that will schedule these controllers over the entire flight envelope
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