Unit four: family

LicenceOf all my relatives, I like my Aunt Emily the best. She's my mother's youngest sister. She has never married, and she lives alone in a small village near Bath. She's in her late fifties, but she's still quite young in spirit. She has a fair complexion, thick brown hair which she wears in a bun, and dark brown eyes. She has a kind face, and when you meet her, the first thing you notice is her lovely, warm smile. Her face is a little wrinkled now, but I think she's still rather attractive. She is the sort of person you can always go to if you have a problem. She likes reading and gardening, and she goes for long walks over the hills with her dog, Buster. She's a very active person. Either she's making something, or mending something, or doing something to help others. She does the shopping for some of the old people in the village. She's extremely generous, but not very tolerant with people who don't agree with her. I hope that I am as happy and contented as she is when I'm her age

Design and performance analysis of global path planning techniques for autonomous mobile robots in grid environments

This article presents the results of the 2-year iroboapp research project that aims at devising path planning algorithms for large grid maps with much faster execution times while tolerating very small slacks with respect to the optimal path. We investigated both exact and heuristic methods. We contributed with the design, analysis, evaluation, implementation and experimentation of several algorithms for grid map path planning for both exact and heuristic methods. We also designed an innovative algorithm called relaxed A-star that has linear complexity with relaxed constraints, which provides near-optimal solutions with an extremely reduced execution time as compared to A-star. We evaluated the performance of the different algorithms and concluded that relaxed A-star is the best path planner as it provides a good trade-off among all the metrics, but we noticed that heuristic methods have good features that can be exploited to improve the solution of the relaxed exact method. This led us to design new hybrid algorithms that combine our relaxed A-star with heuristic methods which improve the solution quality of relaxed A-star at the cost of slightly higher execution time, while remaining much faster than A* for large-scale problems. Finally, we demonstrate how to integrate the relaxed A-star algorithm in the robot operating system as a global path planner and show that it outperforms its default path planner with an execution time 38% faster on average.info:eu-repo/semantics/publishedVersio

Performance analysis of FOC and DTC for synchronous reluctance motor drives

International audienceno abstrac

Performance analysis of FOC and DTC for synchronous reluctance motor drives

International audienceno abstrac

Diagnosis of chronic myeloid leukemia from acute intracerebral hemorrhage: A case report

Intracerebral hemorrhage (ICH) is frequent pathology in emergency departments. Coagulopathies leading to ICH are rare. We describe here the case of diagnosis of a chronic myeloid leukemia from ICH in emergencies

A New Full‐Order Sliding Mode Observer Based Rotor Speed and Stator Resistance Estimation for Sensorless Vector Controlled Pmsm Drives

International audienceSensorless control of a permanent magnetsynchronous motor (PMSM) at low speed remains a challenging task. In this paper, a sensorless vector control of PMSM using a new structure of a sliding mode observer (SMO) is proposed. To remove the mechanical sensors, a full‐order (FO‐SMO) is built to estimate the rotor position and speed of PMSM drives. The FO‐SMO, which replaces a sign function by a sigmoid function, can reduce the chattering phenomenon. In order to overcome time delay, we cancel the low pass filter. This sensorless speed control shows great sensitivity to stator resistance and system noise. To improve the robustness of sensorless vector control, a full‐order SMO technique has been used for stator resistance estimation. A novel stator resistance estimator is incorporated into the sensorless drive to compensate for the effects of stator resistance variation. The validity of the proposed FO‐SMO with a 1.1 kw low‐speed PMSM sensorless vector control is demonstrated by experiments. In this paper, experimental results for FO‐SMO, back‐EMF SMO and MRAS techniques were obtained with fixed point DSP‐based (TMS320F240)

PMSM DTC drive system fed by fault-tolerant inverter connected to a photovoltaic source

International audienceIn this paper experimentation fault-tolerant control for Permanent Magnet Synchronous Motor (PMSM) drive system fed by a three phase inverter connected to a photovoltaic source is presented. PMSM drive system requires uninterrupted and safer conditions during operations. Therefore the diagnostic of voltage source inverter (VSI) and PMSM faults are needed to improve the availability of the system. This article aims to propose an accurate open-phase fault detection and fault-tolerant inverter of a DTC PMSM. The experimental implementation is carried out on powerful dSpace DS1104. The validity of the proposed method has been experimentally verified

A New Full‐Order Sliding Mode Observer Based Rotor Speed and Stator Resistance Estimation for Sensorless Vector Controlled Pmsm Drives

International audienceSensorless control of a permanent magnetsynchronous motor (PMSM) at low speed remains a challenging task. In this paper, a sensorless vector control of PMSM using a new structure of a sliding mode observer (SMO) is proposed. To remove the mechanical sensors, a full‐order (FO‐SMO) is built to estimate the rotor position and speed of PMSM drives. The FO‐SMO, which replaces a sign function by a sigmoid function, can reduce the chattering phenomenon. In order to overcome time delay, we cancel the low pass filter. This sensorless speed control shows great sensitivity to stator resistance and system noise. To improve the robustness of sensorless vector control, a full‐order SMO technique has been used for stator resistance estimation. A novel stator resistance estimator is incorporated into the sensorless drive to compensate for the effects of stator resistance variation. The validity of the proposed FO‐SMO with a 1.1 kw low‐speed PMSM sensorless vector control is demonstrated by experiments. In this paper, experimental results for FO‐SMO, back‐EMF SMO and MRAS techniques were obtained with fixed point DSP‐based (TMS320F240)

Ischemic necrosis of the tongue following transoral neurosurgical procedure

Introduction: Postoperative, lingual swelling and necrosis are unusual complications that can lead to life-threatening airway obstruction. We report a case of bilateral ischemic necrosis of the tongue following transoral neurosurgical procedure. Observation: A Davis-Boyle mouth gag was used for tumor exposition and the operation lasted 8 h. At the end of the surgery, we noticed a bluish discoloration with a mild edema of the tongue. The patient had kept intubated in a monitored setting and intravenous steroids were administered. However, the edema increased and necrosis of the tongue appeared 72 h after the surgery. The patient underwent tracheotomy and the necrotic tissue was removed. More than 15 days passed before glossal engorgement resolved. Discussion: The etiology of tongue necrosis is likely related to tissue ischemia, secondary to venous or arterial obstruction. Prolonged use of the Davis-Boyle mouth gag may incur greater risk of ischemic necrosis of the tongue

On the Robot Path Planning using Cloud Computing for Large Grid Maps

Global path planning consists in finding the optimal path for a mobile robot with the lowest cost in the minimum amount of time, without colliding with the obstacles scattered in the workspace. In this paper, we investigate the benefits of offloading path planning algorithms to be executed in the cloud rather than in the robot. The contribution consists in developing a vertex-centric implementation of RA∗ [1], a version of A∗ that we developed for grid maps and that was proven to be much faster than A∗, using the distributed graph processing framework Giraph that rely on Hadoop. We also developed a centralized cloud-based C++ implementation of the algorithm for benchmarking and comparison purposes. Experimental results on a real cloud shows that the distributed graph processing Giraph fails to provide faster execution as compared to centralized C++ implementation for different map sizes and configuration due to non-real time properties of Hadoop.info:eu-repo/semantics/publishedVersio