著者
太田 憲 梅垣 浩二 室伏 広治 羅 志偉
出版者
一般社団法人日本機械学会
雑誌
シンポジウム: スポーツ・アンド・ヒューマン・ダイナミクス講演論文集
巻号頁・発行日
vol.2010, pp.319-324, 2010-11-02

The motions of a hammer are commonly regarded as a circular movement which a hammer undergoes around a turning human body. The distance of a throw depends on the speed of the hammer and the angle of its trajectory at the instant of release. The speed of the hammer increases gradually during preliminary winds and turns. During each turn the hammer rises up toward the high point of the trajectory and passes through the low point. Our interest in this study was to understand the mechanism of acceleration of the hammer in terms of parametrical excitation. The motions of hammer were analyzed to examine our theory using double pendulum model.
著者
太田 憲 梅垣 浩二 室伏 広治 羅 志偉
出版者
一般社団法人日本機械学会
雑誌
ジョイント・シンポジウム講演論文集 : スポーツ工学シンポジウム : シンポジウム:ヒューマン・ダイナミックス : symposium on sports engineering : symposium on human dynamics
巻号頁・発行日
vol.2009, pp.447-452, 2009-12-02
被引用文献数
1

The motions of hammer were analyzed to understand the mechanism of acceleration using variable-length pendulum and hula-hoop model using energy pumping mechanism. The condition that makes the time derivative of the energy positive is derived as energy pumping for hammer. The condition is expressed in terms of tugging force times velocity to pump hammer energy and tangential acceleration on the handle. In this study, motions of hammer were analyzed and numerical experiments were performed to examine the validity of the theory.
著者
梅垣 浩二 室伏 広治 太田 憲 桜井 伸二
出版者
一般社団法人 日本機械学会
雑誌
シンポジウム: スポーツ・アンド・ヒューマン・ダイナミクス講演論文集
巻号頁・発行日
vol.2012, pp.265-270, 2012

An increase or decrease of the hammer head mechanical energy was caused by an accumulation of the positive or negative handle power which was the product of wire tensile force and handle velocity in the wire length direction. During single support phase a decrease of the wire tensile force was reduced by a fictitious force caused by handle relative pulling acceleration and relative leading velocity to thrower's center of mass (C.M.). Ground reaction force was resulted from maintaining balance with wire tensile force, hammer head centrifugal force, hammer handle coriolis force, and so on under rotational coordinate system. During double support phase handle relative pushing acceleration and relative drawing velocity to thrower's C.M. caused a fictitious force which make balance with the addition of wire tensile force and hammer head rotational force in the wire length direction and with hammer head rotational force in the horizontal direction perpendicular to wire, so that thrower pushed the ground on his/her feet.
著者
太田 憲 梅垣 浩二 室伏 広治 小宮根 文子 桜井 伸二
出版者
一般社団法人 日本機械学会
雑誌
ジョイント・シンポジウム講演論文集:スポーツ工学シンポジウム:シンポジウム:ヒューマン・ダイナミックス
巻号頁・発行日
vol.2008, pp.270-274, 2008

Dynamics-based force sensor using accelerometers which measures forces and joint torques has been developed. In this study we have applied this method to hammer throw training aid integrating small sensors, signal processing, short-range wireless transmission, data-logger and biofeedback training system. The purpose of this study was to establish methods for the measuring of rotational movement and the biofeedback training system for hammer throwers. Microelectromechanical systems accelerometers were chosen as the sensor platform capable of because they are noninvasive miniaturized devices and have wide bandwidth. In this system, a wireless data-logger was developed as a wearable device to replace cables and reduce constraint caused by wearing cables. The transmitted data were given as biofeedback information over a speaker through signal processing and voltage to frequency conversion.
著者
太田 憲 梅垣 浩二 室伏 広治 仰木 裕嗣
出版者
一般社団法人 日本機械学会
雑誌
年次大会
巻号頁・発行日
vol.2014, pp._J2310102--_J2310102-, 2014

The motions of a hammer are commonly regarded as a circular movement which a hammer undergoes around a turning human body. During each turn the hammer rises up toward the high point of the trajectory and passes through the low point. Our interest in this study was to understand the energy transfer mechanism through whole body into the hammer. To elucidate the mechanism novel dynamic equations was derived.