Search results for "Motor"
showing 10 items of 3137 documents
Thought and Body. An activity of Logic in primary school
2015
Abstract In the recent decades, the pedagogical debate has been formerly traversed by the emergence an then by the assertion of a matured awareness on the importance of the psychomotor skills in the educational-didactic path. The interpretive bio-psycho-social matrix has today become one of the pivotal points on which the educational-didactic activity rests and develops for the training of child's personality in its full motor, mental, perceptual, emotional, sensory development. Pedagogues, educators, and training professionals are increasingly confident that, since the birth, children are sensitive to the stimuli and to the environmental intervention, therefore it's essential to know their…
Morphological and Postural Changes in the Foot during Pregnancy and Puerperium: A Longitudinal Study
2021
The aim of this study is to observe the morphological and postural changes to the foot that take place during pregnancy and the puerperium. Method: In this descriptive, observational, longitudinal study, we analysed 23 pregnant women, with particular attention to morphological and postural aspects of the foot, at three time points during and after pregnancy: in weeks 9–13 of gestation, weeks 32–35 of gestation and weeks 4–6 after delivery. The parameters considered were changes in foot length, the Foot Posture Index (FPI) and the Hernández Corvo Index, which were analysed using a pedigraph and taking into account the Body Mass Index (BMI). The same procedure was conducted in each review. Re…
Mathematical performance predicts progress in reading comprehension among 7-year olds
2005
The aim of this longitudinal study was to investigate cross-lagged relationships between mathematical performance and reading comprehension during the first and second years of primary school. 114 Finnish-speaking children were examined six times on mathematics and reading comprehension during Years 1 and 2. At the beginning of Year 1, they were also tested on initial mathematics and reading skill, general concept ability and visual-motor skills. The results showed, firstly, that mathematics and reading comprehension were highly associated with each other across both years. Secondly, mathematical performance predicted subsequent reading comprehension during the first year rather than vice v…
Suspected motor problems and low preference for active play in childhood are associated with physical inactivity and low fitness in adolescence.
2011
Background This prospective longitudinal study investigates whether suspected motor problems and low preference for active play in childhood are associated with physical inactivity and low cardiorespiratory fitness in adolescence. Methodology/Principal Findings The study sample consisted of the Northern Finland Birth Cohort 1986 (NFBC 1986) composed of 5,767 children whose parents responded to a postal inquiry concerning their children's motor skills at age 8 years and who themselves reported their physical activity at age 16 years. Cardiorespiratory fitness was measured with a cycle ergometer test at age 16 years. Odds ratios (OR) and their 95% confidence intervals (95% CI) for the level o…
Experimental Comparison of Efficiency Enhancement Algorithms for Three-Phase Induction Motors
2019
This paper presents an experimental comparison of two efficiency improvement algorithms for three-phase induction motors by adopting Loss Model Algorithms (LMAs). The efficiency enhancement is evaluated starting from several simulations for different conditions of load and speed and, then, validated by comparing the experimental results obtained by applying the two control strategies and the traditional Field Oriented Control (FOC). Significant results in terms of efficiency enhancement are presented and discussed.
Coping with the costs of car dependency : A system of expedients used by low-income households on the outskirts of Dijon and Paris
2018
International audience; Living on low incomes and in a car-dependent area is often interpreted as a double burden for households, even if the two characteristics are often interdependent. While their capacity for mobility is lower, low-income households in outer suburban areas are nonetheless mobile. Their capacities in this domain should not be underestimated or overlooked. They can command a set of alternative practices or expedients to deal with car-related economic stress by a set of resources derived essentially from spatial proximity. This article aims to present and analyse the diversity of these expedients for the case of outer suburban areas around Paris and Dijon. The analysis of …
Adaptive feedback linearizing control of linear induction motor considering the end-effects
2016
This paper proposes an input-output feedback linearization techniques for linear induction motors, taking into consideration the dynamic end-effects. As a main original content, this work proposes a new control law based on the on-line estimation of the induced-part time constant. The estimation law is obtained thanks to a Lyapunov based analysis and thus the stability of the entire control system, including the estimation algorithm, is intrinsically guaranteed. Moreover, with such an approach even the on-lihe variation of the induced-part time constant with the speed is retrieved, thus improving the behavior of previously developed approaches where such a variation vs. speed is considered …
Design and Low-Cost Implementation of an Optimally Robust Reduced-Order Rotor Flux Observer for Induction Motor Control
2007
The aim of this paper is to design and analyze reduced-order observers of the rotor flux of induction motors. The design is carried out in two steps. In the first step, a boundary of the stability region of the observation error is obtained corresponding to a chosen Lyapunov function. In the second step, the boundary is translated into a performance index that is minimized with respect to stator and rotor resistance variations and differences of voltages supplying the motor and those supplying the observer in order to obtain the largest stability region. Implementation of the observer on a low-cost fixed-point digital signal processor using look-up tables is described. Experimental results …
A nonlinear observer for rotor flux estimation considering magnetic saturation effects in induction motor drives
2015
This paper proposes a non-linear observer for In- duction Machine (IM) drives which takes into consideration the saturation effects. The non-linear observer is based on an original formulation of the dynamic model of the IM taking into consideration the magnetic saturation of the iron core. A Lyapunov based convergence analysis is proposed in order to suitably compute the observer gain guaranteeing the stability of the observer. The proposed non-linear observer has been tested in numerical simulation and experimentally on a suitably developed test set-up. Its behaviour has been compared to that obtained with a classic Full-Order Luenberger Observer (FOLO) in variable flux working conditions…
A Nonlinear Observer for Rotor Flux Estimation of Induction Motor Considering the Estimated Magnetization Characteristic
2017
This paper proposes a nonlinear observer for induction machine drives based on space-vector dynamic model of induction machine, expressed in state form, which presents the peculiarity of taking into consideration the magnetic saturation of the iron core. This observer is particularly suitable in order to obtain high accuracy in rotor flux estimation, in both amplitude and phase position, during working conditions characterized by varying flux, among which the most important are those during electrical losses minimization. A Lyapunov-based convergence analysis is proposed in order to suitably compute the numerical observer gain guaranteeing the convergence of the estimation error. The propos…