Deveryware (France)

The model predictive control (MPC) for matrix converters (MCs) typically requires multiple sensors and extensive computational resources to measure various quantities and evaluate control objectives. To address this problem, an efficient MPC approach has been developed for MC-fed motor drives, which entails fewer sensors and less calculation than existing MPC techniques. The proposed method uses one lookup table and a new source current reference calculation to significantly reduce the number of switching state candidates, model predictions, and cost function evaluations. Moreover, Luenberger observers are designed to eliminate sensors for all currents and load torque, under the challenge that MCs directly couple currents and voltages at the source and load sides. With the gain selection structurally optimized, their robustness against electrical and mechanical parameter variations has been rigorously analyzed and validated. Finally, the proposed MPC and benchmark methods are executed and compared in simulation and experiments. The results demonstrate that the proposed method reduces almost half the sensor requirements and 12% computational overhead of the existing simplified method without significantly compromising the system performance, leading to a cost-effective design. The proposed method enables the MPC to work at higher switching frequencies than the traditional ones, thereby mitigating the total harmonic distortion (THD) increases.

This paper presents an overview of several efforts towards reproducible research in the field of medical imaging and visualization. In the first section, the components of Open Science are presented: open access, open data and open source. In the sec

Direct detection of exo-planets from the ground will become a reality with the advent of a new class of extreme-adaptive optics instruments that will come on-line within the next few years on 8-10 meters class telescopes. One major technical challenge in reaching the requisite high contrast at small angles is the sensing and control of wave front errors which becomes even more challenging in the case of the extremely large telescopes. Extensive computer simulations have shown the ability of such systems to deliver high Strehl ratio correction expected (within EPICS preliminary study for instance) but few experiments dedicated to ELTs have been realized so far. This paper will discuss the nature of this problem, and describe recent laboratory results from the LAM Extreme Adaptive Optics bench whose purpose is to provide validation of the numerical simulations as well as to be a testbed to develop concepts, architectures, and control algorithms for the future ELTs extreme adaptive optics systems. This test bench is optimized for ultra-high contrast applications requiring XAO with realistic telescope conditions reproduced by star and turbulence generators and including segmented primary mirror. We present here preliminary results, showing an RMS wavefront control at level smaller than 10 nm rms for static aberrations.

Highly performing adaptive optical (AO) systems are mandatory for next generation giant telescopes as well as next generation instrumentation for 10m-class telescopes, for studying new fields like circumstellar disks and extra-solar planets. These systems require deformable mirrors with very challenging parameters, including number of actuators up to 250 000 and inter-actuator spacing around 500μm. MOEMS-based devices are promising for future deformable mirrors. We are currently developing a micro-deformable mirror (MDM) based on an array of electrostatic actuators with attachment posts to a continuous mirror on top. In order to reach large stroke for low driving voltage, the originality of our approach lies in the elaboration of a sacrificial layer and of a structural layer made of polymer materials. We have developed the first polymer piston-motion actuator: a 10μm thick mobile plate with four springs attached to the substrate, and with an air gap of 10μm exhibits a piston motion of 2μm for 30V, and measured resonance frequency of 6.5kHz is well suited for AO systems. The electrostatic force provides a non-linear actuation, while AO systems are based on linear matrices operations. We have successfully developed a dedicated 14-bit electronics in order to linearize the actuation. Actual location of the actuator versus expected location of the actuator is obtained with a standard deviation of 21 nm. Comparison with FEM models shows very good agreement, and design of a complete polymer-based MDM has been done.

The prelims comprise: Half-Title Page Wiley Finance Series Title Page Copyright Page Table of Contents About the Contributors Preface

This chapter consolidates results presented and achieved during the three EUREX workshops that focussed on project management. Two of these workshops were held in France, including the initial prototype workshop, and one was held in Britain.