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In this paper, a robust active fault tolerant control (AFTC) scheme is proposed for induction motor drives (IMD) via input-output linearization control (IOLC) and nonlinear observer. In order to estimate the states and to reconstruct the faults, two different observers are used; a Luenberger observer (LO) and an extended kalman filter (EKF). Further we introduce feedback linearization strategy by choosing the output function as the rotor speed and flux square. To provide a direct comparison between these FTCs schemes, the performance is evaluated using the control of IMD under failures, variable speed, and variable parameters, finally the obtained results show that the proposed controller with the proposed observers provides a good trajectory tracking, and these schemes are robust with respect to faults, parameter variations, and external load disturbances for induction motor drive system.

Background: Efforts to improve alternative CD4 T-cell counting methods are critical to accelerate the implementation of HIV antiretroviral therapy in resources limited regions. Substituting liquid format reagents to eliminate cold-chain transportation and refrigerated storage with dry format reagents contributes to higher efficiency supply management solution especially for laboratories at remote locations. ReaMetrix has developed dry format reagent kits compatible with the FACSCount system, a dedicated flow cytometer for T-cell subset enumeration widely used in resource limited settings. A dual site collaborative study was designed to compare T-cell subsets using both the new dry format ReaMetrix reagent and the original BD Biosciences liquid reagents.Method: A total of 167 HIV positive samples prepared with Rea T Count (ReaMetrix) and FACSCount (BD Biosciences) reagents were analyzed using FACSCount Systems. To compare both methods, Bland-Altman, Pollock, Scott % similarity and correlation coefficient statistical analysis was applied. Immuno-Trol served as an assay processing control and quality indicator of interlaboratory and intralaboratory variation.Results: The mean bias and limits of agreement for CD4 T-cell measurements between Rea T Count and FACSCount reagents were 216 cells/ll (24.6%) and 274 to 143, respectively. The correlation obtained was 0.988 with a similarity of 97.9%. Between laboratory variation data was very good with %CV below 10%.Conclusion: The introduction of dry reagents permits the elimination of cold-chain transportation and the on-site refrigerated storage without compromise to assay quality. The substitution of dry reagents facilitates easier supply management practice that will assure wider access to quality HIV treatment. V C 2009 Clinical Cytometry Society

In this paper, a control algorithm based on Backstepping technique for differential drive mobile robot path tracking is developed. The use of backstepping theory to solve the problem of path tracking is relatively new in the field of mobile robots control. Numerical simulations were conducted to show the effectiveness of the proposed algorithms to solve the nonholonomic constraints of the mobile robot, and its ability to achieve satisfactory performance. The stability of the system is proven via Lyapunov theory.

The wind system based on double-fed induction generator (DFIG) has become a very important source of energy. To ensure the proper functioning of this system, many improved control algorithms have been developed for the rotor side converter (RSC). This article presents the analysis and design of a double-fed induction generator (DFIG) control technique based on coupling the type-2 fuzzy logic control with the sliding mode control (SMC). For the design of this technique, a decoupled modeling of the DFIG with the orientation of its stator flow is presented. The main purpose of the proposed technique is to make a control to meter the quantities of the powers produced by DFIG which are injected into the electrical network and to reduce the phenomenon of chattering which depends on control by sliding mode. This command has allowed us to reduce the chattering phenomenon and improve the performance of the system in terms of speed monitoring and stator side powers regulation. Simulations are performed using MATLAB / Simulink to validate the effectiveness of the proposed control algorithm. The simulation results, obtained when applying this control strategy to the system, demonstrated the validity of the results and thus validated the high performance of this control technique.

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Original scientific paperThis paper proposes an improved sensorless fault-tolerant control (FTC) for high-performance induction motor drives (IMD) that propels an electric-vehicle (EV). The design strategy is based on the Backstepping control (BC). However an appropriate combination of the BC and extended kalman filter (EKF) is done, this later is designed in order to detect and reconstruct the faults and also to give a sensorless control. Then, additional control laws, based on the estimates of the faults, are designed in order to compensate the faults. The results show the superiority EKF in nonlinear system as it provides better estimates for faults detection. A classical EV traction system is studied, using an IMD. Indeed, the IMD based powertrain is coupled to DC machine-based load torque emulator taking into account the EV mechanics and aerodynamics. Finally, the effectiveness of the proposed strategy for detection of faults, and FTC of the IMD is illustrated through simulation studies. Key words: Backstepping control (BC), Fault-tolerant control (FTC), Induction motor drives (IMD), Extended kalman filter (EKF), Electric vehicle (EV).Rekurzivna izvedba za uočavanje kvarnih stanja i upravljanje otporno na kvarna stanja električnih vozila zasnovanih na indukcijskim motorima. U ovome radu predložena je unaprije ena bez-senzorska upravljačka strategija otporna na kvarna stanja (FTC) za indukcijski motor visokih performansi koji pokreće električno vozilo (EV). Strategija je temeljena na rekurzivnom upravljanju (BC). Nadalje, izvedena je odgovarajuća kombinacija BC-a i proširenog Kalmanovog filtra (EKF), pričemu je potonji izveden u svrhu uočavanja i rekonstrukcije kvarova te kako bi omogućio bez-senzorsko upravljanje. Kako bi se kompenzirala kvarna stanja, dizajnirani su dodatni upravljački zakoni zasnovani na estimaciji kvarova. Rezultati prikazuju poboljšanje korištenjem EKF-a za nelinearne sustave budući da on omogućava kvalitetnije uočavanje kvarova. Razmatran je klasični pogon EV-a korištenjem IMD-a. Tako er, pogonski sklop zasnovan na IMD-u je povezan s emulatorom momenta zasnovanom na DC motoru, uzimajući u obzir mehaničke i aerodinamičke karakteristike EV-a. Na posljetku je simulacijama ilustrirana efikasnost predložene strategije za uočavanje kvarnih stanja i FTC-a IMD-a.Ključne riječi: Rekurzivno upravljanje (BC), upravljanje otporno na kvarna stanja (FTC), indukcijski motor (IMD), prošireni kalmanov filtar (EKF), električno vozilo (EV). INTRODUCTIONA motor control system with high robustness is an important issue in research. Induction motor drives (IMD) are making significant inroads, because of robustness and rugged structure. They are widely used in industrial applications such as, electric vehicles (EVs), traction locomotives etc. In the last decade, fault tolerance becomes an interesting topic in their controls. The objective is to give solutions that provide fault accommodation to the most frequent faults and thereby reduce the costs of handling the faults. Backstepping control (BC) is a robust...

-This paper describes a sensorless fault-tolerant control (FTC) for a high-performance induction motor drive that propels an electric-vehicle (EV). The effect of the fault on the induction motor (IM) can be modeled by an exogenous signal from a stable autonomous system. An additive term is added to the nominal offset and serves to control the effect of the defect (FTC aspect). The proposed sensorless FTC for IM is realized in presence of both rotor and stator electrical faults. Consequently, the extended kalman filter (EKF) is proposed to estimate the rotor flux and the rotor speed using the measured stator currents and voltages. Therefore, a classical EV traction system is studied using an induction motor drive. Indeed, the induction motor based powertrain is coupled to DC machine-based load torque emulator taking into account the electric vehicle mechanics and aerodynamics. Simulation and experimental results confirm widely the feasibility and the effectiveness of the proposed FTC of IM based SMC in the electric vehicle application.