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1

Muscle coordination analysis by time-varying muscle synergy extraction during cycling across various mechanical conditions

Esmaeili Javad, Maleki Ali

Biocybernetics and Biomedical Engineering

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2020

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Vol. 40, no. 1

90--99

EN

Central nervous system (CNS) uses the combination of a small number of motor primitives, named muscle synergies, for simplification of motor control in human movement. The aim of this study was to investigate the muscle coordination in both leg muscles during pedaling by time-varying muscle synergy extraction. Twenty healthy subjects performed three 6-min cycling tasks over a range of rotational speed (40, 50, and 60 rpm) and resistant torque (3, 5, and 7 N/M). Surface electromyography signals were recorded during pedaling from eight muscles of the right and left lower limbs. We extracted four time-varying muscle synergies from sEMG patterns. Mean and standard deviation of the quality of the signal reconstruction (R2) for all subjects was obtained 0.9328 ± 0.0120. We investigated the similarity of muscle synergies during cycling across various mechanical conditions. We found the high degrees of similarity (>0.85) among the sets of time-varying muscle synergies across mechanical conditions and also across subjects. Our results show that the same motor control strategies for cycling are used by all subjects in various mechanical conditions.

2

Konstrukcja i sterowanie trójkołowego roweru elektrycznego bez przekładni mechanicznej

Brock S., Fabiański B., Wicher B., Zawirski K.

Maszyny Elektryczne : zeszyty problemowe

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2018

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Nr 2 (118)

185--190

PL

W pracy przedstawiono konstrukcję prototypu oryginalnego trójkołowego pojazdu napędzanego pedałami ze wspomaganiem elektrycznym, bez sprzężenia mechanicznego korby pedałów z kołami. Każde z kół pojazdu jest napędzane przez bezszczotkowy silnik elektryczny (BLDC). Pedały napędzają generator, który ładuje baterię akumulatorów. Zaprojektowany został układ dystrybucji energii, zapewniający bezpieczne zachowanie się napędów pojazdu w warunkach awaryjnych. Zaprojektowane i zbudowane zostały centralny układ sterowania oraz dedykowane przekształtniki energoelektroniczne, a całość komunikacji odbywa się z wykorzystaniem protokołu CAN-open. Jako jednostkę sterującą zastosowano układ STM32F407, który pełni rolę sterownika we wszystkich podsystemach pojazdu. Prędkość pojazdu jest proporcjonalna, z nastawianym współczynnikiem, do prędkości pedałowania, natomiast moc dostarczana do silników poszczególnych kół jest odpowiednio większa od mocy generowanej przez rowerzystę. Dużą uwagę zwrócono na ergonomiczne właściwości układu napędowego, dopasowując charakterystykę momentu oporowego generatora do naturalnej charakterystyki pedałowania. W ten sposób układ napędowy zachowuje się analogicznie do klasycznego roweru mechanicznego.

EN

The paper presents the construction of a prototype of an original three-wheeled electrically powered vehicle. The vehicle is driven by pedals without mechanical coupling of the crank handle with the wheels. Each of the vehicles wheels is driven by a brushless electric motor (BLDC). The pedals drive a generat or that charges the battery. The power distribution system has been designed to ensure the safe behaviour of the vehicle's drives under emergency conditions. The central control system and dedicated power electronic converters have been designed and built, and all communicationis performed using the CAN-open protocol. STM32F407 is used as the control unit for all subsystems. Thespeed of the vehicle is proportional to the pedalling speed, with a variable factor, and the power supplied to the motors of the individual wheels is correspondingly higher than the cycling power. Considerable attention was paid to the ergonomic characteristics of the drive unit, adjusting the torque characteristics of the generator to the natural characteristics of the pedal system. In this way, the drive system behaves similarly to a classic mechanical bike.

3

The analysis of pedaling techniques with platform pedals

Stępniewski A. A., Grudziński J.

International Journal of Applied Mechanics and Engineering

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2014

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Vol. 19, no. 3

633--642

EN

The paper analyzes a pedaling technique with platform pedals in which the influence of the geometric and tribological parameters on the torque course of the active forces in the crank rotation axis is determined. Distribution of forces of feet acting on pedals as a function of the crank rotation angle was performed and on this basis the specific pedaling zones and their ranges and the courses of the value of variable active torque and pedaling work during the full cycle were determined. The course of changes in the movements in the ankle joint is described with a function depending on the crank and limb position and loading of the joint. A numerical example has also been presented and a discussion of the results has been carried out.

4

The necessity of physiological muscle parameters for computing the muscle forces: application to lower extremity loading during pedalling

Čadová M., Vilímek M.

Acta of Bioengineering and Biomechanics

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2009

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Vol. 11, nr 3

59-64

EN

The aim of this study is to determine how the use of physiological parameters of muscles is important. This work is focused on musculoskeletal loading analysis during pedalling adopting two approaches: without (1) and with (2) the use of physiological parameters of muscles. The static-optimization approach together with the inverse dynamics problem makes it possible to obtain forces in individual muscles of the lower extremity. Input kinematics variables were examined in a cycling experiment. The significant difference in the resultant forces in one-joint and two-joint muscles using the two different approaches was observed.