INFLUENCE OF THE GOLF CLUB ON THE SWING MOTION

This study analyzed the influence of the golf club on the swing motion. An experiment was carried out using three 7-irons of different mass and shaft stiffness. Performance was recorded with 10 motion capture cameras, psychological evaluation was evaluated by questionnaire, and the ballistic was measured with a golf ballistic measuring instrument. We analyzed position in the vertical direction of a right wrist marker and considered the flow of the swing motion. We calculated the standard deviation to analyze difference in the swing motion. Comparing the standard deviation, the ballistic measurement results and psychological evaluation, standard deviations could be used as objective evaluation indicators for selecting clubs

EXAMINATION OF EVALUATION INDEX OF TENNIS RACKET SELECTION WITH STROKE MOTION ANALYSIS

The purpose of this paper is to build a selection index for tennis rackets. Tennis rackets were evaluated using motion indices derived by investigating the effects of rackets on stroke movement. The subjects of this study were three male senior tennis players and two male beginner players. Stroke motion and the three-dimensional information of each part of the human body was measured with 12 motion capture cameras and 6 rackets with different characteristics. By using three-dimensional information, characteristic markers of the tennis strokes were derived. The vertical position of the marker was analyzed, and the change in the stroke motion of each racket was examined. The analysis was performed by comparing the sum of standard deviation and swing speed. As a result, the relationship between the sum of the standard deviation and the swing speed for the stroke motion was shown. It was suggested that a racket suitable for beginners may be presented by presenting the sum of the standard deviation of the z-axis position of the right wrist marker, which has a high correlation with the swing speed, as a racket index

INFLUENCE OF THE RACKET ON THE SMASH MOTION IN BADMINTON

The purpose of this study was to analyze the influence of the racket on badminton smash motion. An experiment was carried out using three badminton rackets of different mass and gravity center position. The smashes of 12 males were selected for the analysis. Performances were recorded by twelve motion capture cameras. In this study, we analyzed a position in the vertical direction of each marker and considered a series of the flow of the smash motion. Then, we calculated the standard deviation to analyze a difference of the smash motion. As a result, a difference in dispersion of the smash motion was observed depending on using the rackets. In addition, some inexperience persons could be close to motions of experience by changing the rackets. Therefore, the result showed that it was very important to select a racket suitable for them

SWING-UP CONTROL OF MASS BODY INTERLINKED FLEXIBLE TETHER

One of the applications of tether system is in the field of satellite technology, where the mother ship and satellite equipment are connected with a cable. In order to grasp the motion of this kind of tether system in detail, the tether can be effectively modeled as flexible body and dealt by multibody dynamic analysis. In the analysis and modeling of flexible body of tether, large deformation and large displacement must be considered. Multibody dynamic analysis such as Absolute Nodal Coordinate Formulation with an introduction of the effect of damping force formulation can be used to describe the motion behavior of a flexible body. In this study, a parameter identification technique via an experimental approach is proposed in order to verify the modeling method. An example of swing-up control using the genetic algorithm control approach is performed through simulation and experiment. The validity of the model and availability of motion control based on multibody dynamics analysis are shown by comparison between numerical simulation and experiment

Space demostration of bare electrodynamic tape-tether technology on the sounding rocket S520-25

A spaceflight validation of bare electro dynamic tape tether technology was conducted. A S520-25 sounding rocket was launched successfully at 05:00am on 31 August 2010 and successfully deployed 132.6m of tape tether over 120 seconds in a ballistic flight. The electrodynamic performance of the bare tape tether employed as an atmospheric probe was measured. Flight results are introduced through the present progressive report of the demonstration and the results of flight experiment are examined as the premier report of the international cooperation between Japan, Europe, USA and Australia. Future plans for maturing space tether technology, which will play an important role for future space activities, are also discussed

T-REX: Bare electro-dynamic tape-tether technology experimetn on sounding rocket S520

The project to verify the performance of space tether technology was successfully demonstrated by the launch of the sounding rocket S520 the 25tu. The project is the space demonstration of science and engineering technologies of a bare tape electrodynamic tether (EDT) in the international campaign between Japan, USA, Europe and Australia. Method of "Inverse ORIGAMI (Tape tether folding)" was employed in order to deploy the bare tape EDT in a short period time of the suborbital flight. The deployment of tape tether was tested in a various experimental schemes on ground to show high reliability of tape tether deployment. The rocket was launched on the summer of 2010 and deployed a bare electro-dynamic tape tether with length 132.6 m, which is the world record of the length deployment of tape tether. The verification of tether technology has found a variety kind of science and technology results as the first in the humankind and will lead a large number of applications of space tether technologie

Dynamic Contact between a Wire Rope and a Pulley Using Absolute Nodal Coordinate Formulation

Wire rope and pulley devices are used in various machines. To use these machines more safely, it is necessary to analyze the behavior of the contact between them. In this study, we represent a wire rope by a numerical model of a flexible body. This flexible body is expressed in the absolute nodal coordinate formulation (ANCF), and the model includes the normal contact force and the frictional force between the wire rope and the pulley. The normal contact force is expressed by spring-damper elements, and the frictional force is expressed by the Quinn method. The advantage of the Quinn method is that it reduces the numerical problems associated with the discontinuities in Coulomb friction at zero velocity. By using the numerical model, simulations are performed, and the validity of this model is shown by comparing its results with those of an experiment. Through numerical simulations, we confirm the proposed model for the contact between the wire rope and the pulley. We confirmed that the behavior of the wire rope changes when both the bending elastic modulus of the wire rope and the mass added to each end of the wire rope are changed

Tether Space Mobility Device Attitude Control during Tether Extension and Winding

Recently, advancements in space technology have opened up more opportunities for human beings to work in outer space. It is expected that upsizing of manned space facilities, such as the International Space Station, will further this trend. Therefore, a unique means of transportation is necessary to ensure that human beings can move about effectively in microgravity environments. In the present study, we propose a tether-based mobility system, which moves the user by winding a tether attached to a structure at the destination. However, there is a problem in that the attitude of the user becomes unstable during winding of the tether. Therefore, a Tether Space Mobility Device (TSMD) attitude control method for winding a tether is examined through numerical analysis. The proposed analytical model consists of one flexible body and three rigid bodies. The contact force between the tether and the inlet is considered. We verified the validity of the proposed model through experiments. Furthermore, we proposed a TSMD attitude control method during tether winding while focusing on changes in the system’s rotational kinetic energy. Using the proposed analytical model, the angular velocity of a rigid body system is confirmed to converge to 0 deg/s when control is applied