To make an accurate movement, the CNS has to overcome the inherent complexities of the multijoint limb. For example, interaction torques arise when motion of individual arm segments propagates to adjacent segments causing their movement without any muscle contractions. Since these passive joint torques significantly add to the overall torques generated by active muscular contractions, they must be taken into account during planning or execution of goal-directed movements. We investigated the role of the corticospinal tract in compensating for the interaction torques during arm movements in humans. Twelve subjects reached to visual targets with their arm supported by a robotic exoskeleton. Reaching to one target was accompanied by interaction torques that assisted the movement, while reaching to the other target was accompanied by interaction torques that resisted the movement. Corticospinal excitability was assessed at different times during movement using single-pulse transcranial magnetic stimulation (TMS) over the upper-arm region of M1 (primary motor cortex). We found that TMS responses in shoulder monoarticular and elbow–shoulder biarticular muscles changed together with the interaction torques during movements in which the interaction torques were resistive. In contrast, TMS responses did not correlate with assistive interaction torques or with co-contraction. This suggests that the descending motor command includes compensation for passive limb dynamics. Furthermore, our results suggest that compensation for interaction torques involves the biarticular muscles, which span both shoulder and elbow joints and are in a biomechanically advantageous position to provide such compensation.

Категория: Ищем научные статьи | Нет комментариев »

Мобильные приложения как относительно новый вид ПО не перестают удивлять нас и своей популярностью, и инновационными решениями. Некоторые из них имеют самое непосредственное отношение к передовым научным изысканиям, которые пять-десять лет назад воспринимались бы как нечто фантастическое и совершенно невозможное в реальном мире.

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Категория: Управление | Нет комментариев »

В технопарке «Digital October» прошел финал общероссийского конкурса бизнеспланов «Бизнес инновационных технологий» (БИТ), проводимый при поддержке корпорацииIntel и Российской венчурной компании (РВК). В этом году в финале конкурса БИТ приняли участие 13 команд из Москвы, СанктПетербурга,Воронежа, Нижнего Новгорода и Томска. До выхода в финал команды прошли региональный отбор и победили в полуфинале, получив право приехать в Москву и представить свои проекты на суд компетентного жюри. Основными требованиями дляучастия в конкурсе являлось наличие оригинальной бизнесидеи и предпринимательской команды. В этом году призовой фонд конкурса составил 5 млн руб. (включая призовые фонды региональных конкурсов БИТ). Также призовой фонд конкурса включал не монетарные компоненты, связанные с образовательными программами и возможностью участия команд в международных конкурсах бизнеспланов.

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Категория: EXOMEN | Нет комментариев »

Current active leg prostheses do not integrate the most recent advances in Brain-Computer Interfaces (BCI) and bipedal robotics. Moreover, their actuators are seldom driven by the subject’s intention. In this paper, we propose an original and biologically-inspired leg prosthesis control scheme, which brings together these three aspects. It is composed of an EOG-based eye tracker and a Programmable Central Pattern Generator (PCPG). In a first step, specific sequences of eye movements executed by the user are identified by the eye tracking system. These sequences are then converted to high-level commands (such as accelerate, decelerate or stop) and sent to the prosthesis actuator control unit. In this unit, a PCPG is implemented, which is able to model human walk in a perfectly periodic way. One of the main interests of that tool is the possibility to modify the gait pattern to adapt to different walking speeds in a smooth way. Several results from previous studies are summarized and discussed in order to demonstrate the feasibility of such a system.

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Wearable haptic devices with poor position sensing are combined with the Kinect depth sensor by Microsoft. A heuristic hand tracker has been developed. It allows for the animation of the hand avatar in the virtual reality and the implementation of the force rendering algorithm: the position of the fingertips is measured by the hand tracker designed and optimized for Kinect, and the rendering algorithm computes the contact forces for wearable haptic display. Preliminary experiments with qualitative results show the effectiveness of the idea of combining Kinect and wearable haptics.

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Категория: Научные статьи | Нет комментариев »