Locomotion Control With Frequency and Motor Pattern Adaptations

Existing adaptive locomotion control mechanisms for legged robots are usually aimed at one specific type of adaptation and rarely combined with others. Adaptive mechanisms thus stay at a conceptual level without their coupling effect with other mechanisms being investigated. However, we hypothesize that the combination of adaptation mechanisms can be exploited for enhanced and more efficient locomotion control as in biological systems. Therefore, in this work, we present a central pattern generator (CPG) based locomotion controller integrating both a frequency and motor pattern adaptation mechanisms. We use the state-of-the-art Dual Integral Learner for frequency adaptation, which can automatically and quickly adapt the CPG frequency, enabling the entire motor pattern or output signal of the CPG to be followed at a proper high frequency with low tracking error. Consequently, the legged robot can move with high energy efficiency and perform the generated locomotion with high precision. The versatile state-of-the-art CPG-RBF network is used as a motor pattern adaptation mechanism. Using this network, the motor patterns or joint trajectories can be adapted to fit the robot's morphology and perform sensorimotor integration enabling online motor pattern adaptation based on sensory feedback. The results show that the two adaptation mechanisms can be combined for adaptive locomotion control of a hexapod robot in a complex environment. Using the CPG-RBF network for motor pattern adaptation, the hexapod learned basic straight forward walking, steering, and step climbing. In general, the frequency and motor pattern mechanisms complement each other well and their combination can be seen as an essential step toward further studies on adaptive locomotion control.

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State of the art of particle emissions in thermal spraying and other high energy processes based on metal powders

Journal of Cleaner Production ◽

10.1016/j.jclepro.2021.126952 ◽

2021 ◽

pp. 126952

Author(s):

G. Darut ◽

S. Dieu ◽

B. Schnuriger ◽

A. Vignes ◽

M. Morgeneyer ◽

...

Keyword(s):

State Of The Art ◽

Thermal Spraying ◽

High Energy ◽

Metal Powders ◽

Particle Emissions ◽

Energy Processes

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High-energy-density lithium-ion battery using a carbon-nanotube–Si composite anode and a compositionally graded Li[Ni0.85Co0.05Mn0.10]O2 cathode

Energy & Environmental Science ◽

10.1039/c6ee01134a ◽

2016 ◽

Vol 9 (6) ◽

pp. 2152-2158 ◽

Cited By ~ 183

Author(s):

Joo Hyeong Lee ◽

Chong S. Yoon ◽

Jang-Yeon Hwang ◽

Sung-Jin Kim ◽

Filippo Maglia ◽

...

Keyword(s):

Carbon Nanotube ◽

Energy Density ◽

Lithium Ion Battery ◽

State Of The Art ◽

Lithium Ion ◽

High Energy ◽

High Energy Density ◽

Rechargeable Battery ◽

Composite Anode ◽

Battery System

A Li-rechargeable battery system based on state-of-the-art cathode and anode technologies demonstrated high energy density, meeting demands for vehicle application.

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A Study of Exchange-Coupling Effect on Nd2Fe14B / α-Fe Forming Core/Shell Shape

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.119.147 ◽

2007 ◽

Vol 119 ◽

pp. 147-150 ◽

Cited By ~ 4

Author(s):

Chang Woo Kim ◽

Young Hwan Kim ◽

Don Keun Lee ◽

In Chul Jeong ◽

Hae Woong Kwon ◽

...

Keyword(s):

Exchange Coupling ◽

Ball Mill ◽

Coupling Effect ◽

Chemical Reduction ◽

High Energy ◽

Shell Shape ◽

Core Shell ◽

High Energy Ball Mill ◽

Energy Ball ◽

Mill Process

We report the core/shell type as the interesting one of the various techniques to prepare exchange-coupled permanent magnet. In this study, the exchange-coupled Nd2Fe14B/α-Fe was prepared by high energy ball mill process and chemical reduction. Nd15Fe77B8 powder prepared by high energy ball mill process was coated with α-Fe nanoparticle by chemical reduction. α-Fe nanoparticle on the ball milled Nd15Fe77B8 was synthesized by chemical reduction with borohydride as a reducing agent in aqueous solution. After annealing, Nd2Fe14B/α-Fe forming core/shell shape has exchange-coupling effect and was identified by using XRD, FE-SEM, VSM, TMA and EDX.

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Compressed Sensing-Based DOA Estimation with Unknown Mutual Coupling Effect

Electronics ◽

10.3390/electronics7120424 ◽

2018 ◽

Vol 7 (12) ◽

pp. 424 ◽

Cited By ~ 11

Author(s):

Peng Chen ◽

Zhenxin Cao ◽

Zhimin Chen ◽

Linxi Liu ◽

Man Feng

Keyword(s):

Compressed Sensing ◽

Mutual Coupling ◽

Linear Array ◽

State Of The Art ◽

Coupling Effect ◽

Estimation Method ◽

Doa Estimation ◽

System Model ◽

Reconstruction Problem ◽

Uniform Linear Array

The performance of a direction-finding system is significantly degraded by the imperfection of an array. In this paper, the direction-of-arrival (DOA) estimation problem is investigated in the uniform linear array (ULA) system with the unknown mutual coupling (MC) effect. The system model with MC effect is formulated. Then, by exploiting the signal sparsity in the spatial domain, a compressed-sensing (CS)-based system model is proposed with the MC coefficients, and the problem of DOA estimation is converted into that of a sparse reconstruction. To solve the reconstruction problem efficiently, a novel DOA estimation method, named sparse-based DOA estimation with unknown MC effect (SDMC), is proposed, where both the sparse signal and the MC coefficients are estimated iteratively. Simulation results show that the proposed method can achieve better performance of DOA estimation in the scenario with MC effect than the state-of-the-art methods, and improve the DOA estimation performance about 31.64 % by reducing the MC effect by about 4 dB.

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Assessing adaptation capabilities in primary school children attending schools with different educational processes

Hygiene and Sanitation ◽

10.47470/0016-9900-2021-100-5-495-500 ◽

2021 ◽

Vol 100 (5) ◽

pp. 495-500

Author(s):

Olga A. Maklakova ◽

Darya A. Eisfeld ◽

Nina V. Zaitseva

Keyword(s):

Primary School ◽

School Children ◽

Teaching And Learning ◽

Educational Process ◽

Primary School Children ◽

Adaptation Mechanism ◽

Nervous Systems ◽

Adaptation Mechanisms ◽

Educational Processes ◽

And Mathematics

Introduction. Innovative teaching and learning systems involve intensification of the educational process and greater academic loads; it results in the exertion of adaptation systems in a body, especially when it comes to primary school children. Purpose of the study. Our research goal was to assess peculiarities of adaptation capabilities in primary school children who attended schools with different educational processes. Material and methods. To study peculiarities of adaptation capabilities in primary school children, we performed a clinical examination of 183 children (51.4% boys and 48.6% girls, the average age being 9.51±0.17) who attended a lyceum (group A), a school with advanced studies of physics and mathematics (Group B), and an ordinary secondary school (Group C). We also analyzed how intense educational loads were in all three educational establishments. Children’s adaptation capabilities were assessed as per functional parameters of their cardiovascular and vegetative nervous systems and catecholamines’ contents in blood. Results. The entry-level secondary schools tend to have more intense educational processes. We established that primary school children who attended a lyceum faced 1.5 times greater intellectual and sensory loads; children who attended a school with advanced studies of physics and mathematics had educational loads that were 1.3-1.4 times more monotonous than in other establishments; children who attended an ordinary school had to bear 1.8 times higher emotional loads. ⅔ primary school children had exertion of functional reserves in their cardiovascular system caused by a longer educational load duration. 36% of primary school children who attended a school with advanced studies of physics and mathematics had tension in their adaptation mechanisms caused by monotonous educational loads combined with lower noradrenalin contents in blood. Those children also ran up to 4.9 times higher risks of adaptation mechanism exertion. 48.5-56.7% of children who attended a lyceum and an ordinary school had vegetative imbalance that became apparent via activated adaptation-trophic influence promoted by the sympathetic section in the vegetative nervous systems and related to the duration of learning activities. Conclusion. Intensification of the educational process results in disorders of compensatory-adaptation mechanisms in primary school children.

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Luminescent tracks of high-energy photoemitted electrons accelerated by plasmonic fields

Nanophotonics ◽

10.1515/nanoph-2015-0029 ◽

2015 ◽

Vol 4 (4) ◽

pp. 511-519

Author(s):

Marcel Di Vece ◽

Giorgos Giannakoudakis ◽

Astrid Bjørkøy ◽

Wingjohn Tang

Keyword(s):

Confocal Microscopy ◽

State Of The Art ◽

Field Enhancement ◽

Optical Excitation ◽

High Energy ◽

Intense Laser ◽

Electron Interaction ◽

Intense Laser Pulse ◽

Local Field Enhancement ◽

Metal Nanostructure

AbstractThe emission of an electron from a metal nanostructure under illumination and its subsequent acceleration in a plasmonic field forms a platform to extend these phenomena to deposited nanoparticles, which can be studied by state-of-the-art confocal microscopy combined with femtosecond optical excitation. The emitted and accelerated electrons leave defect tracks in the immersion oil, which can be revealed by thermoluminescence. These photographic tracks are read out with the confocal microscope and have a maximum length of about 80 μm, which corresponds to a kinetic energy of about 100 keV. This energy is consistent with the energy provided by the intense laser pulse combined with plasmonic local field enhancement. The results are discussed within the context of the rescattering model by which electrons acquire more energy. The visualization of electron tracks originating from plasmonic field enhancement around a gold nanoparticle opens a new way to study with confocal microscopy both the plasmonic properties of metal nano objects as well as high energy electron interaction with matter.

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