WSEAS CONFERENCES. WSEAS, Unifying the Science

Main Page of the Journal                      All 2008                        Main Page of the WSEAS

August 2007, Sept. 2007, Oct. 2007, Nov. 2007, Dec. 2007, 2008


Issue 11, Volume 2, November 2007
Print ISSN: 1991-8763
E-ISSN: 2224-2856







Title of the Paper:  Robust Stability Analysis for 2-D Continuous-Time Systems Via Parameter-Dependent Lyapunov Functions


Authors: M. Alfidi And A. Hmamed

Abstract: New sufficient conditions to test stability of 2-D linear continuos-time systems described by Roesser model with polytopic uncertainty are presented in this paper. Robust stability is guaranteed by the existence of a parameter-dependent Lyapunov function obtained from the feasibility of a set of Linear Matrix Inequalities(LMIs), formulated at the vertices of the uncertainty polytope. Two conditions are presented, and the results are compared with the analysis based on quadratic stability (same Lyapunov function for the entire set of uncertainties). Several examples are presented to illustrate the results.

Keywords: 2-D continuous-time systems, Robust stability, parameter-dependent Lyapunov functions, Linear matrix inequalities (LMIs), polytopic uncertainty, Roesser model.

Title of the Paper: Modeling and Derivation of Back EMF and Torque Constants of Gearless Flat-Type Brushless DC Motor


Authors: Jian-Long Kuo, Tsung-Yu Wang,

Abstract: This paper develops the mathematical modeling for the gearless flat-type brushless DC motor. The major two machine constant coefficients will be investigated to derive the compact form related to the machine size and material property. Static and dynamic testing will be employed to illustrate the validity of the discussed machine. The compact formulation will be demonstrated through experimental results. A mathematical approach, based on the electromagnetic field theory, will be used to formulate the two machine constants. The aim of this paper is to provide good guidance for designing the associated gearless-flat type brushless motor. It can be found that some of the geometry parameters will affect the performances of the proposed machine. The theoretical modeling will be developed to show characteristics such as Back-EMF and torque constants.

Keywords: gearless, flat-type, brushless motor, Back EMF constant, torque constant.

Title of the Paper: Simulation of Electromagnetic Devices Using Coupled Models


Authors: Ion Cārstea, Daniela Cārstea, Alexandru Adrian Cārstea

Abstract: This work presents numerical algorithms for simulation of distributed-parameter systems with direct applications in electrical engineering. The algorithms are developed in the context of the finite element method. Many works in the professional literature present coupled models for the electromagnetic devices and this work is toward this direction with emphasis on the development of efficient algorithms in numerical computation of the coupled models. Our work describes the solution of coupled electromagnetic and heat dissipation problems in two dimensions and cylindrical-coordinates system for devices with cylindrical symmetry. The purpose of the work is to define both conventional algorithms and parallel algorithms for coupled problems in context of the finite element method. The mathematical models for electromagnetic field are based on potential formulations. Some numerical results are presented.

Keywords: Coupled fields; Finite element method; Domain decomposition.

Title of the Paper: Self-Equilibrium Control on a Dynamic Bicycle Ride


Authors: Chieh-Tsung Chi

Abstract: It is very important for a biker to ride comfortably and safely around everywhere. Through analyzing the stability characteristic of a bicycle when it was driven on each sloping road, the position of the center of gravity (COG) was commonly one of the key influencing factors. Therefore, this study presented a simple approach to measure the inclination degree of sloping road and fed to the system controller for changing the COG position. Moreover, the front-to-back adaptive equilibrium control of a bicycle ride was controlled by means of a hysteresis algorithm, and built in a control unit. The COG position of a whole bicycle system allowed to be changed by either manual or automatic mode which was completely dependent upon biker decision. For convenience, an experimental prototype had first been established in the laboratory. Later, several experiments, such as the feasibility and flexibility concerning system control structure were related to a bicycle were performed on the prototype. Simulation and experimental results showed that the dynamic equilibrium of a bicycle when it was driven on each sloping road could be controlled by using the posture control approach proposed in this paper. In addition, the increasing cost concerning additional facilities was cheap and easily retrofitted into the existing bicycles.

Keywords: Bicycle, Center of gravity, Hysteresis controller, Sloping road, Equilibrium control, Cost.

[Journals], [Books], [Conferences], [Research], [Contact us], [Indexing], [Reports], [E-Library], [FAQ],
[Upcoming Conferences with Expired Deadline], [History of the WSEAS Conferences]

Copyright © WSEAS