 |
View: 1-15 | 16-30 | 31-45 | 46-60 | 61-69
Robust Control of A
Speed Sensorless
A.A. Hassan and M. Azzam
Pages: 252-257
Abstract: This paper presents the application of the Linear Quadretic Gaussian (LQG) controller to the state estimation and feedback of a speed sensorless permanent magnet synchronous motor (PMSM) drive system. The nonlinear model of the motor has been linearized on the basis of field orientation principle. The standard Kalman filter technique has been used to estimate the speed, position, and load torque by measuring only the stator current. The optimal state feedback gains and the Kalman state space model have been calculated off-line in order to reduce the computational burden. The proposed controller has the advantages of robustness, easy implementation and adequate performance in the face of uncertainties. Moreover, the load disturbance can be rejected without affecting the overall performance. Computer simulations have been carried out in order to validate the effectiveness of the proposed scheme. The results show that accurate tracking performance of the PMSM has been achieved.
Modeling and Parameter Estimation of a
Catalyst Deactivation Fluidized Bed Reactor
S. Papadopoulou1, G. Kokolaki1, I.
Anastasiou1,
1Alexander Technol. Educ. Inst. of Thessaloniki,
Greece, 2Chem. Proc. Eng. Res.
Inst./CERTH, Thessaloniki, Greece
Pages: 258-264
Abstract: The aim of the present work is the development of a detailed dynamic mathematical model of a fluidized bed reactor with distributed parameters, in radial and axial direction, which will form the basis of a model predictive controller. A set of partial differential equations describes the dynamic behavior of the conductive and convective heat transfer. The model is divided in five sections in accordance to the heating sections of the reactor. In each section the model contains six different sub models corresponding to the six different layers that make up the reactor in the radial direction. The model validation and the parameter estimation were performed using dynamic experimental data from the unit at different operating conditions. Optimal estimates for key parameters were calculated using the Maximum Likelihood method. The obtained results revealed the ability of the model to predict accurately the operation of the reactor unit.
Optimal Control of
R. Gerasimjak1, L. Melnikova1 and A. Shestaka2
1Odessa National Polytechnic
Univ., Ukraina, 2JV Trans
Service, Odessa, Ukraina
Pages: 264-267
Abstract: Optimal control of drive rotational mechanisms accounting for the mechanical components is considered. A control method that provides damping of the suspended load and reduces the dynamic loads is proposed. Results of the system simulation are presented.
An Automatic System for Aircraft Collision
Avoidance in Free Flight: The 3-D Case
M. Christodoulou1,
1Techn. Univ. of Crete,
Pages: 268-275
Abstract: In this paper, we consider optimal resolution of air traffic (AT) conflicts. Aircrafts are assumed to cruise within a free altitude layer and are modeled in 3-D dimensions with variable velocity and proximity bounds. Aircrafts cannot get closer to each other than a predefined safety distance. We consider the problem of solving conflicts arising among several aircrafts that are assumed to move in a shared airspace. For such systems of multiple aircrafts, we are interested in optimal path, i.e. we want to minimize the total flight time by avoiding all possible conflicts. This paper proposes one formulation of the multi-aircraft conflict avoidance problem as a mixed integer non linear programming problem. In our case, only velocity changes are admissible as maneuvers. Nevertheless in subsequent work we will be checking for simultaneous velocity and heading angle changes too. Simulation results for realistic aircraft conflict scenarios are provided.
A SysML Extension for Bond Graphs Support
S. Turki and T. Soriano
LISMMA,
Pages: 276-281
Abstract: In this paper we present a contribution to SysML for energy interchange depiction. This contribution consists of an extension to the activity diagram. We mapped it to the Bond Graph formalism which is often used for the design of mechatronic systems. We use the extension mechanisms that SysML inherits from UML2.0 such as stereotypes and tagged values to establish mapping rules from activities to bond graphs. The paper is concluded by an example to illustrate this proposal.
Sensor Fault Detection
in Building Energy Management Systems
D. Kolokotsa1, A. Pouliezos2 and G.
Stavrakakis2
1Technol. Educ. Inst. of Crete,
Pages: 282-287
Abstract: In this specific paper a methodology for detecting sensor failures in building energy management systems is presented. The fault diagnosis decision criterion is the average absolute prediction error between the actual and the predicted values of the sensor. Τhe predicted value is calculated by a model based on normal operation data. Three experiments are presented with simulated biases in the temperature, illuminance and CO2 sensors. Although the concept is simple, the results for fault detection are quite satisfactory.
Space Vector Pulse Width
Modulation Applied to the Three-Level Voltage Inverter
H. Djeghloud and H. Benalla
Pages: 288-293
Abstract: Advances in power electronics technology allowed the wide investigation of multilevel converters that provide high safety voltages with less harmonic components compared to the two-level structures. Employed for converter's gating signals generation, the space-vector pulse width modulation (SVPWM) strategy reduces the switching losses by limiting the switching to the two thirds of the pulse duty cycle. This study aims to explain, via simple and easy algebraic expressions, the application of the SVPWM on the three-level voltage inverter. The theoretical study was numerically simulated using Simulink under Matlab software.
Determination of Quality
Parameters of Hoisting
K. Khandakji1 and K. Zdrozis2
1Tafila
Pages: 294-296
Abstract: This paper illustrates a mathematical analysis of AC hoisting electric drive systems (incorporating three-phase reversible voltage controlled – slip-ring induction motors) for determining the main quality parameters of the transient processes. The effect of the quality parameters on the shape of the system transients is shown using the derived mathematical model. A new closed-loop control system to enhance the character of transients is suggested.
Fault Detectability of
Double Analogue Measurements Using Probabilistic Analysis
D. Papakostas1 and A. Hatzopoulos2
1Alexander Technol. Educ. Inst. of
Pages: 297-300
Abstract: Statistical multi-parameter circuit simulation is used in this work, in order to estimate the fault detection probability in cases where double analogue measurements are utilized. Theoretical analysis for the estimation of the detectability is given, based on conditional probability calculations. The proposed technique can also be applied for test measurement selection. Simulation results from the application of the method on an analogue filter circuit are given, showing a sufficient improvement over the detectability achieved by single measurements.
Automation and
Flexibility of Analog Systems Diagnostics
P. Bilski and J. Wojciechowski
Pages: 301-306
Abstract: The paper provides general insight into the analog systems diagnostics architecture. Automation of the wavelet transform de-noising procedure is presented. Decision trees based fuzzy logic decision making module for single and multiple fault detection of the 4th order servomechanism is described. The factor for assessment of the diagnostic quality considering limited size of the learning data structure is proposed.
A Fault Diagnosis Expert
System Structure with Knowledge Retrieving Capability from Waveforms
D. Papakostas1 and A. Hatzopoulos2
1Alexander Technol. Educ.
Inst. of
Pages: 307-311
Abstract: Analogue fault diagnosis can be addressed by expert systems using artificial intelligence methodologies. The structure of such an expert system and its main features are presented in this paper. As a special feature, knowledge which is obtained through the waveforms of specific parameters of the circuit under test is presented. Techniques for comparison between waveforms and conclusion extraction are described. Demonstrative examples of fault location using the expert system are given.
V. Signal and Image Processing
Full Interactive
MPEG-Based Wireless Video Streaming
K. Psannis and Y. Ishibashi
Nagoya Inst. of
Pages: 312-317
Abstract: Despite much research in the field of mobile media, delivery of real time interactive video over noisy wireless channels remains a challenging problem. A major limitation in wireless networks is that mobile users must rely on a battery with a limited supply of energy. Effectively utilizing this energy is a key consideration in the design of wireless networks. In this paper, we jointly consider source coding and dynamic allocation of the physical layer communication resources in an efficient method. The proposed efficient approach achieves acceptable visual quality using minimum transmission energy, while satisfying delay constraints. Mechanism for controlling the interactive streams is also presented and its effectiveness is assessed through extensive simulations.
On the Reduction of
Congestion for Multimedia Streaming in Diffserv Networks
P. Fouliras and C. Georgiadis
Pages: 318-321
Abstract: In this paper, we propose a simple meter and classification scheme, specifically designed for real-time multimedia streaming applications in Diffserv QoS networks. This is based upon the observation that conformance deterioration takes place on such networks for all traffic of variable-size packets. We show that it is simple to detect, shape and drop packets which experience exceeding delay, thus reducing the incurring congestion and providing better network resource utilization.
Analog Signal Processing Circuits Using
Floating Gate MOS Transistors
M. Drakaki1, G. Fikos2 and
1Alexander Technol. Educ. Inst. of
Pages: 322-327
Abstract: Low voltage non-linear computational circuits useful for analog VLSI signal processing applications based on floating gate MOS transistors (FGMOSFETs) are presented. The FGMOS transistors operate in the saturation region. The variable equivalent threshold voltage (VT) of the FGMOS transistor is exploited in such a way to transform it to a simple MOSFET of zero VT. A bias circuit using a conventional VT extractor circuit makes the transformation. The transistor behaves as a simple squaring element in this case. A four-quadrant multiplier and a Euclidean norm calculator circuit are presented as applications. The most important advantages of the four-quadrant multiplier are rail-to-rail dynamic input range, low distortion and very good linearity. The main advantages of the Euclidean norm calculator circuit are unipolar supply voltage, linear expansion requiring only one FGMOS per additional input and very good linearity. SPICE simulation results verify the accuracy of the circuits.
Realization of a
Signature Verification System Based on Morphological Transformation and Using
the TMS320C6713 Digital Signal Processor
E. Zois, E. Pikasis, Z. Kotsidimou, P. Tsitouras, and A.
Nassiopoulos
Technol. and Educ. Inst.
of
Pages: 328-333
Abstract: In this paper a feature vector, which has been used for curve coding, is evaluated in case of a signature verification scheme using a real time digital signal processor. The feature extraction method is based on morphologically processing the vertical projections of prescaled signature images. Coding of the curve profiles is carried out using morphological opening which explores the pixel allocation along the directions of projection. Various lengths for the structuring element are employed to increase feature discrimination capabilities. The method has been implemented using the Texas Instruments TMS320C6713 digital signal processor in conjunction with the MATLAB and SIMULINK software. The efficiency of the method is examined using a new signature database which comprises 70 writers. The classification approach uses the weighted distance as a similarity measure. An error rate lower that 0.02% is obtained for the case of random and zero effort forgery.
View: 1-15 | 16-30 | 31-45 | 46-60 | 61-69 | Back to top