Search results for "internal"

Internal model-based feedback control design for inversion-free feedforward rate-dependent hysteresis compensation of piezoelectric cantilever actuat…

2018

Abstract This study proposes a new rate-dependent feedforward compensator for compensation of hysteresis nonlinearities in smart materials-based actuators without considering the analytical inverse model. The proposed rate-dependent compensator is constructed with the inverse multiplicative structure of the rate-dependent Prandtl–Ishlinskii (RDPI) model. The study also presents an investigation for the compensation error when the proposed compensator is applied in an open-loop feedforward manner. Then, an internal model-based feedback control design is applied with the proposed feedforward compensator to a piezoelectric cantilever actuator. The experimental results illustrate that the propo…

Integration of gradient based and response surface methods to develop a cascade optimisation strategy for Y-shaped tube hydroforming process design

2010

International audience; In the last years a strong research effort was produced in order to develop and design new forming technologies able to overcome the typical drawbacks of traditional forming operations. Among such new technologies, hydroforming proved to be one of the most promising. The design of tube hydroforming operations is mainly aimed to prevent bursting or buckling occurrence and such issues can be pursued only if a proper control of both material feeding history and internal pressure path during the process is performed.In this paper, a proper optimisation strategy was developed on Y-shaped tube hydroforming process which is characterized by a quite complex process mechanics…

Vibration reduction on city buses: Determination of optimal position of engine mounts

2010

International audience; This study is composed of three essential parts. The first part describes an indirect semi-experimental method which is used to reconstruct the excitation force of an operating diesel engine from the acceleration data measured at the mounting points. These internal forces can not be directly measured with force sensors; they have to be derived from the dynamic deformation of the engine support, so a theoretical analysis is carried out to derive the equations for the force re-construction.The second part deals with prevention of low frequency vibration of the powertrain from spreading to the rest of the vehicle. Three uncoupling techniques are used to minimize these v…

Design of a robust controller for DC/DC converter–electrolyzer systems supplied by μWECSs subject to highly fluctuating wind speed

2020

Abstract A buck-based, isolated, high-voltage-ratio DC/DC converter that allows supplying a proton exchange membrane (PEM) electrolyzer from a micro-wind energy conversion system ( μ WECS) has been recently presented. It exhibits low ripple at the switching frequency on the output voltage and current and represents an attractive solution for low-cost hydrogen production. In this paper, a more accurate mathematical model of such a converter is derived and discussed. Then, a model-based robust controller is designed in the frequency domain using the Internal Model Control structure and in the context of H 2 ∕ H ∞ optimal control. The controller satisfies the condition of robust stability and …

2018

Physical fitness is crucial to warfighters' performance in the battlefield. Previous studies have shown negative changes in their hormonal and neuromuscular responses induced by military field training (MFT). The purpose of this study was to investigate the changes in hormonal and immunological values and body composition during a prolonged MFT and to find out how warfighters' physical condition influences these changes. Conscripts (n = 49, age 20 ± 1 years, height 179 ± 9 cm, body mass 73.8 ± 7.8 kg, fat 12.6 ± 3.7% and BMI 23 kg/m²) were measured before, during, after MFT, and after a 4-day recovery period. Serum insulin-like growth factor-1 (IGF-1), tumor necrosis factor alpha (TNF-α), i…

Infarctus du myocarde au cours de l’artérite à cellules géantes : étude de cohorte

2020

Introduction Le risque d’evenement cardiovasculaire est accru au cours de l’arterite a cellules geantes (ACG), en particulier dans les premiers mois suivant le diagnostic de la vascularite [1] . L’objectif de ce travail etait de decrire les caracteristiques des infarctus du myocarde (IDM) survenant chez des patients atteints d’ACG et de les comparer avec des IDM survenant chez des patients ne presentant pas d’ACG au moment de leur IDM. Patients et methodes Les patients atteints d’ACG ont ete identifies parmi la liste des biopsies d’artere temporale (BAT) qui montraient des lesions d’ACG et qui avaient ete analysees entre le 1er janvier 2001 et le 31 decembre 2016 dans les deux laboratoires …

Escala de percepción ante crisis y pandemias : desarrollo y validación de una escala pedagógica

2021

Objetivos: Abordar la metodología de estudio con respecto a epidemia/pandemia requiere involucrar pensamiento complejo frente a los retos que denota esta situación. El objetivo de este estudio es validar un cuestionario de percepción y creencias dirigido a estudiantes de medicina y enfermería sobre el uso del cine ante la complejidad de un evento pandémico, con el propósito de potenciar las estrategias de enseñanza. Metodología: Se encuestó a 131 estudiantes. La evaluación de la confiabilidad se realizó a través del análisis de consistencia interna. La valoración de los 19 ítems se evaluó mediante análisis de correlación de Pearson y la validez de constructo mediante análisis factorial expl…

What is science without replication?

2016

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Stakeholder Contradictions in Early Stages of eHealth Efforts

2017

Rezept für Bewegung in der Nephrologie

2018

ZusammenfassungDie Behandlung der chronischen Niereninsuffizienz (chronic kidney disease, CKD) in Klinik und Praxis, auch unter der Dialysetherapie, beinhaltet stets eine umfangreiche medikamentöse Gabe und eine regelmäßige Überwachung. Die Niereninsuffizienz als chronische Erkrankung gehört zu der Gruppe von Krankheiten, die auch von einer nicht medikamentösen Therapie profitiert – nämlich von einer regelmäßigen körperlichen Aktivität. Trotz zahlreicher Publikationen zu diesem Thema werden Bewegung und körperliche Aktivität noch zu wenig bei Patienten mit CKD eingesetzt. Mit den Ergebnissen des Trainings während der Dialyse und dem Rezept für Bewegung gibt es effektive Ansätze, die Faktore…