Search

Ce travail presente des techniques, basees sur les modes glissants, permettant d'estimer des parametres, de reconstruire des variables (observateur) et/ou de commander un moteur pas-a-pas. Le but etant de realiser un suivi de trajectoire en position robuste avec un minimum de capteurs. Apres avoir defini le contexte de l'etude, la planification et l'optimisation des trajectoires et les objectifs, le banc realise au LAGIS est decrit. Il est alors presente une identification des parametres par plusieurs methodes. Les proprietes de platitude du moteur pas-a-pas sont utilisees. Des commandes classiques sont rapidement developpees et illustrees de resultats experimentaux. Cependant, elles ne sont pas assez de robustes vis a vis de perturbations internes (incertitudes ou variations parametriques) ou externes (couple de charge). Pour pallier ce probleme, des lois de commande par modes glissants, d'ordre 1 et 2, sont alors utilisees. Apres une description, des experimentations sont menees qui demontrent les qualites des modes glissants. Un nouveau mode glissant d'ordre 3, base sur l'homogeneite geometrique et un terme additionnel de type mode glissant integral, est introduit pour diminuer la reticence. Les resultats experimentaux montrent une tres bonne precision, une diminution de la reticence et de la consommation energetique. Pour les commandes d'ordre deux et trois, des observateurs par modes glissants d'ordre 2 sont utilises avec succes pour se passer d'un capteur de vitesse.

We undertook a prospective MRI study to measure the retroversion of the humeral head in 33 consecutive infants with a mean age of 1 year 10 months (3 months to 7 years 4 months) who had an obstetric brachial plexus lesion (OBPL). According to a standardised MRI protocol both shoulders and humeral condyles were examined and the shape of the glenoid and humeral retroversion determined. The mean humeral retroversion of the affected shoulder was significantly increased compared with the normal contralateral side (-28.4 +/- 12.5 degrees v -21.5 +/- 15.1 degrees, p = 0.02). This increase was found only in the children over the age of 12 months. In this group humeral retroversion was -29.9 +/- 12.9 degrees compared with -19.6 +/- 15.6 degrees in the normal shoulder (p = 0.009), giving a mean difference of 10.3 degrees (95% confidence interval 3.3 to 17.3). This finding is of importance when considering the operative treatment for subluxation of the shoulder in children with an OBPL

Item does not contain fulltext 4 p.

International audience; In this paper a circuit-based simulation model is defined for a PV cell in order to allow estimating the electrical behaviour of the cell with respect changes on environmental parameter of temperature and irradiance. Maximum power point trackers (MPPT) play an important role in photovoltaic (PV) power systems because they maximize the power output from a PV system for a given set of conditions, and therefore maximize the array efficiency. DC-DC converters together with MPPT systems are used to avoid the energy losses. Different algorithms have been proposed for maximum power point tracking, the Perturb & Observe (P&O) and Incremental Conductance (incCond) methods are illustrated in this work. In this paper the implementation of a photovoltaic model using Matlab/Simulink are presented, which can be representative of PV cell module, for easy use on simulation platform. Taking the effect of sunlight irradiance and cell temperature into consideration, the output current and power characteristics of PV model are simulated and optimized using the proposed model. Next, a voltage control of a photovoltaic system is studied in order to have a constant voltage at the output, always keeping the system to operate at maximum power. Indeed, in most industrial applications, the load must be supplied by a constant voltage. The simulation results are carried out using Matlab/Simulink.

We have analysed a series of 49 human breast cancers for mutations in the entire coding region plus flanking intron sequences of the E-cadherin gene. The tumours included 41 infiltrating lobular carcinomas, two infiltrating ducto-lobular carcinomas and six infiltrative ductal carcinomas. In the lobular carcinomas 23 different somatic mutations were detected, of which seven were insertions, 11 deletions, two nonsense mutations and three splice site mutations. The other tumours showed no detectable E-cadherin mutations. All the frameshift and nonsense mutations are expected to generate a secreted E-cadherin fragment instead of a transmembrane protein with cell adhesion activity. The majority of the mutations (21 of 23) were found in combination with loss of heterozygosity of the wild type E-cadherin locus (16q22.1), a hallmark of classical tumour suppressor genes. The mutations were scattered over the whole coding region and no hot spots could be identified. All mutations described here were previously unreported. In conclusion, we have identified up to now E-cadherin mutations in 27 of 48 (56%) infiltrating lobular breast carcinomas and in 0 of 50 breast cancers of other histopathological subtypes. These data provide strong evidence that frequent E-cadherin mutations are involved in the particular etiology of sporadic lobular breast cancers.

International audience; The two important disadvantages of Direct Torque and Flux Control (DTC), are torque and flux ripples and stator resistance variation (which affects seriously the estimation stator flux and electromagnetic torque). This paper proposes a fuzzy-logic based DTC (FLC) using modified switching table for permanent magnet synchronous motor (PMSM) and Fuzzy-logic Resistance Estimator. The high-performance of the proposed FLC applied to PMSM drive, are investigated and compared with traditional DTC. The proposed system has proven successful in controlling the instantaneous torque so as not to depend only on the estimation flux, torque and position, but also on variable amplitude torque hysteresis bands and stator resistance (r s) delivered by fuzzy-logic.

In this paper, the wind electrical conversion system (WECS) is described; the structure of WECS is based on the Induction generator. The global model of the WECS is presented. A study of the electrical parts (Induction machine and static converter) is developed. The goal of this paper is to control the power generated by the WECS to the grid. A strategy of control is developed signed based on the vector control applied to Induction Machine. A new controllers are designed using variable structure control with sliding mode to control active and reactive power. Simulation study was done to prove the validation of the strategy of control used and to show the high performance and robustness of the control technique used in power control.