Search results for "Motor"
showing 10 items of 3137 documents
Design and Characterization of a Miniature Hydraulic Power Supply for High-Bandwidth Control of Soft Robotics
2020
Soft robotics holds enormous promise for a wide class of applications. However, system controllability, bandwidth, portability, and energy efficiency of soft robot power supplies are often inadequate. Soft robotics desperately needs improved solutions to drive soft actuators either pneumatically or hydraulically. This research paper offers a contribution to bridge this gap. It deals with small-scale power supplies for hydraulically-driven soft robots based on fluidic elastomer actuators in the power range 5-400 W. A design procedure for such power supplies is developed with an emphasis on high-bandwidth control. The performance requirements are established based on a literature survey, and …
Controllable Solid Rocket Motor Nozzle Operations in Conditions of Limited-Amplitude Fluctuations
2009
A nonlinear multi scale analysis of a controllable solid rocket motor operating in conditions ranging from high-amplitude fluctuations in combustion chamber to conditions lying in limit cycle is presented and the motor behavior subsequent to some relevant nozzle operations is investigated. Effects of acoustic-vorticity-entropy wave coupling, wave steepening, rotational/viscous flow losses, steep-fronted wave losses are taken into account and oscillatory energy losses in pintle-nozzle, unsteady combustion and chamber geometry changes resulting from grain regression are included. The analysis provides evidence that the unsteady energy balance and the motor wave amplitude evolution are influen…
How is gravity integrated into motor planning : behavioural and fMRI approaches
2016
Gravity is immutable, ubiquitous and affects the dynamic of our daily movements. The gravitational attraction (9.81 m / s2) which varies less than 1% of the earth's surface, is an actress of the evolution of all living species. Thanks to an efficient sensorimotor system, the dynamical consequences of the effects of gravity on our movements are stored as internal representations. To circumvent the time delays of the afferent signals coming from the sensorimotor system (too long to plan quick movements), the Central Nervous System (CNS) acts in a proactive fashion by using suitable internal models developed during our past experiences. These models are mainly used during the motor planning to…
Design and Experimental Test of a Thermomagnetic Motor
2012
Abstract This paper presents a Thermomagnetic Motor. The design of the motor is based on a thermal-magnetic coupled dynamic model, which is obtained by assuming the use of a ferromagnetic material working at temperatures near the curie point. The motor is modeled in terms of both its magnetic as well thermal properties (magnetic permeability and thermal conductivity) and the thermal processes are supposed to be influenced by the thermal conductivity, the convection and the advection. An analytical expression of the generated torque, which links this quantity to the magnetic, thermal and geometrical parameters of the generated torque is given. A design of a machine, based on this theory is p…
ALTERAZIONI DEL RECETTORE OCULARE E COMPENSI DELLA COLONNA CERVICO-DORSALE: PARAMETRI STABILOMETRICI
2009
Scopo dello studio è stato quello di analizzare la relazione tra atteggiamento scoliotico dorsale e difetti di convergenza oculare. In 40 soggetti giovani adolescenti maschi di età compresa tra 10 e 12 anni è stata eseguita una valutazione delle curve rachidee con scoliosometro ed un esame stabilometrico mediante piattaforma Baropodometrica Elettronica Modulare “Diagnostic Support”, da cui sono stati ricavati la velocità di variazione, la deviazione media coronale (x-medio), la deviazione media sagittale (y-medio) e la superficie e lunghezza dello statokinesigramma. Inoltre, per l’analisi della funzionalità del recettore oculare, sono stati effettuati il test di convergenza oculare e il cov…
An Interaction Path of Mothers’ and Preschoolers’ Food-and Physical Activity-Related Aspects in Disadvantaged Sicilian Urban Areas
2021
Background: The relationship between mothers and their children’s lifestyle is still unclear, especially in disadvantaged areas. Consequently, the study aims to identify a path explaining the extent to which maternal eating habits and physical activity (PA) level predict food-related aspects, PA practice and Quotient of Gross Motor Development (QGMD) in preschoolers from disadvantaged urban areas. Methods: In this cross-sectional study, a total of 79 dyads of mothers and children were recruited from kindergartens. Information related to family socio-demographic aspects, mothers’ and children’s dietary intake frequencies and PA/sedentariness, mothers’ weight and height, mothers’ perception o…
The Effect of COVID-19 Lockdown Measures on Physical Activity Levels and Sedentary Behaviour in a Relatively Young Population Living in Kosovo
2021
To abate the spread of the COVID-19 virus, different restriction measures were imperative, limiting the possibility to be engaged in physical activity. Therefore, this study aimed to evaluate the effect of COVID-19 lockdown on physical activity (PA) levels expressed as energy expenditure (MET-min/week) and sedentary behaviour in Kosovo. The possible association between PA levels and other factors was analyzed. 1633 participants (age range: 13 to 63 years; mean: 24.70 ± 9.33 years; body height: 172 ± 10.57 cm; body mass: 69.10 ± 13.80 kg; BMI: 23.09 ± 3.63 kg/m2) participated in the study, categorized by age, gender, BMI, and living area. An online survey, including an adapted version of the…
Physical Activity Levels and Related Energy Expenditure during COVID-19 Quarantine among the Sicilian Active Population: A Cross-Sectional Online Sur…
2020
Background: During the coronavirus disease 2019 (COVID-19) pandemic, the Italian government has adopted containment measures to control the virus’s spread, including limitations to the practice of physical activity (PA). The aim of this study was to estimate the levels of PA, expressed as energy expenditure (MET–minute/week), among the physically active Sicilian population before and during the last seven days of the COVID-19 quarantine. Furthermore, the relation between this parameter and specific demographic and anthropometric variables was analyzed. Methods: 802 Sicilian physically active participants (mean age: 32.27 ± 12.81 years; BMI: 23.44 ± 3.33 kg/m2) were included in the study and…
Effects of muscle action type on corticospinal excitability and triceps surae muscle-tendon mechanics
2014
The present study was designed to investigate corticospinal excitability modulation during maximum isometric and eccentric muscle actions with two different velocities. Moreover, the study aimed to clarify the effect of muscle action type on muscle-tendon mechanical behavior in order to shed light into the possible role of sensory information in modulating corticospinal excitability during different muscle actions. We compared motor evoked potentials (MEPs) to transcranial magnetic stimulation and Hoffman reflexes (H-reflex) in soleus muscle during isometric, slow eccentric (25 deg/s) and fast eccentric (100 deg/s) muscle actions. Concomitantly, ultrasonography was utilized to access soleus…
Effects of comprehensive geriatric assessment and targeted intervention on mobility in persons aged 75 years and over: a randomized controlled trial
2011
Objective: To assess the effect of a comprehensive geriatric assessment and individually tailored intervention on mobility in older people. In addition, the effectiveness of the geriatric intervention was evaluated among a subgroup of persons with musculoskeletal pain. Design: Three-year geriatric development project with randomized assignment to intervention and control group. Setting: Research centre, community and assisted living facilities. Participants: Seven hundred and eighty-one Finnish persons aged 75–98 years were assigned to an intervention ( n = 404) or control ( n = 377) group. Intervention: A comprehensive geriatric assessment with a multifactorial intervention lasting two ye…