著者
小林 吉之 嶺 也守寛 藤本 浩志
出版者
一般社団法人 日本機械学会
雑誌
日本機械学会論文集 C編 (ISSN:03875024)
巻号頁・発行日
vol.73, no.725, pp.274-279, 2007-01-25 (Released:2011-03-04)
参考文献数
14
被引用文献数
1 1

To determine the accuracy of foot position sense in the means of foot placement, young adults were asked to place either medial edge or lateral edge of their feet along the base line on the floor as close as possible, and the edge of placed feet were scanned by using laser displacement gauge. From the collected data, constant error, the distances between the edge of placed feet and the base line on the floor, and absolute error, the absolute distances between the edge of placed feet and the base line on the floor were defined and compared between the medial or lateral trials, and dominant leg or indominant leg. The statistical analysis showed significant differences of constant error between the trials only. The trials to place their medial edge tend to place their feet away from the base line, and the trials to place their lateral edge tend to place their feet in to the base line. These results indicate that we tend to expect the position of our feet more medially than actual, and these discrepancy may be one of a reasons of tripping or banging of our feet to the obstacles while walking.
著者
橋本 良夫 斉藤 敏克
出版者
The Japan Society of Mechanical Engineers
雑誌
日本機械学会論文集 C編 (ISSN:03875024)
巻号頁・発行日
vol.69, no.687, pp.3029-3033, 2003

A method is proposed to analyze dynamic response of a rocket-launcher system at lift-off. In this paper, rocket-launcher system is modeled as finite element Bernoulli-Euler beams connected with two slippers which are modeled as linear springs. A beam element with a moving spring is devised to represent the rocket-launcher interaction. Coupled equations of motion with time-varying coefficients are derived and solved by using direct method such as the Wilson θ method to calculate the dynamic response of the system. To verify the validity of this method, dynamic response is calculated by using the data of M-3S rocket-launcher system. Two rocket models, rigid-body and elastic-body models, are used in this calculation. The numerical results obtained from two models are compared and discussed.
著者
堤 一郎
出版者
一般社団法人 日本機械学会
雑誌
日本機械学会論文集 C編 (ISSN:03875024)
巻号頁・発行日
vol.74, no.746, pp.2387-2395, 2008-10-25 (Released:2011-03-04)
参考文献数
17

Wooden carriage manufacture of Japanese Imperial Government Railway (J. I. G. R.) Works and Japanese young railway engineer cultivation in the Meiji period are described. In the start of J. I. G. R.'s transport business, 143 rolling stocks were imported from the U. K., and English railway engineers were employed. They cultivated Japanese young trainees through the construction of wooden carriages by themselves on the job training. A drawing of Adams bogie track with Munsell wheels, brief personal record of four English railway engineers and three Japanese young engineers were explained. Mechanical Engineering Heritage of four wooden carriages preserved in Japan are introduced, too.
著者
鈴木 曠二
出版者
The Japan Society of Mechanical Engineers
雑誌
日本機械学会論文集 C編 (ISSN:03875024)
巻号頁・発行日
vol.50, no.457, pp.1736-1739, 1984

The Dynamic Soaring is the soaring technique making use of the wind gradient. The order, Albatross belongs to, includes several species which use this technique and have various scale. Main conclusion is as follows: They practice almost physically similar dynamic soaring. The larger one practices a larger dynamic soaring and requires a stronger wind than the smaller one does, in the wind near the sea surface. Such a scale effect corresponds with the fact that a Wandering Albatross lives in the zone of the westerlies of the Southern hemisphere; on the other hand, a Streaked Shearwater which is smaller than it lives in areas where it is not so windy. But if the wind profile was almost linear, the said relation between the scale of a bird and the wind strength would be reversed.
著者
白國 紀行 谷村 正治 宮崎 文夫
出版者
一般社団法人 日本機械学会
雑誌
日本機械学会論文集 C編 (ISSN:03875024)
巻号頁・発行日
vol.72, no.716, pp.1021-1027, 2006-04-25 (Released:2011-03-04)
参考文献数
4

Among high-speed railway systems, the superconducting maglev train is an innovative transportation system, in which trains are levitated and driven at speeds of up to 550 km/h. But in case of quench of superconducting magnet, vehicles are forced to touch down on the guideway. For safe landing, we developed the new equipment named “Emergency Wheel”. Our process of development is as follows : (i) To know the maximum load for the landing, we simulated the electromagnetic power and dynamics of vehicles. (ii) Each element of emergency wheel was developed and tested in a factory. (iii) Quench tests were conducted on the Yamanashi Maglev Test Line and results showed a good accordance between simulation and test. Through the study and development of emergency wheel, we established a design method of safety equipment for Maglev.
著者
山田 健介 宮本 共生 臼井 清一
出版者
一般社団法人 日本機械学会
雑誌
日本機械学会論文集 C編 (ISSN:03875024)
巻号頁・発行日
vol.71, no.708, pp.2557-2562, 2005-08-25 (Released:2011-03-04)
参考文献数
8
被引用文献数
4 3

The paper presents a design and characteristics of a new holonomic omnidirectional moving vehicle, which simultaneous and independently controlled translational and rotational motions. The moving vehicle has four rubber balls instead of wheels. Each ball is driven by two rotating rollers. But the system has only four actuators. The kinematics of the moving vehicle is analyzed and the control algorithms are derived for the holonomic and omnidirectional moving vehicle. The experimental results show that the proposed new type of moving mechanism has good characteristics and the sensor on board is useful for autonomous moving under relatively large disturbance.
著者
山中 仁寛 中易 秀敏 三好 哲也 前田 多章
出版者
一般社団法人 日本機械学会
雑誌
日本機械学会論文集 C編 (ISSN:03875024)
巻号頁・発行日
vol.72, no.719, pp.2248-2256, 2006-07-25 (Released:2011-03-04)
参考文献数
17

A new method is proposed to measure the useful field of view (UFOV) when one can recognize the objects by visual task. Since the distance from fixation point to target mark is the strength of stimuli, the psychometric curve is utilized for UFOV by the statistical estimation by Probit and Staircase methods. An approximation by ellipse is also applied to represent the contour of the UFOV. The proposed method enables one to estimate the threshold of recognition with probability that means the UFOV with the detection probability. Therefore, it is proposed in this paper to determine the threshold in any direction from fixation point of the UFOV with visual task by psychometric curve. The availabilities of the proposed method are examined for accuracy and efficiency by the experiments.
著者
新宮 正弘 江口 清 山海 嘉之
出版者
一般社団法人 日本機械学会
雑誌
日本機械学会論文集 C編 (ISSN:03875024)
巻号頁・発行日
vol.76, no.772, pp.3630-3639, 2010
参考文献数
24
被引用文献数
1

Polio survivors with severe limb paralysis cannot move their limbs voluntarily because they have a significantly reduced number of motor neurons due to the poliovirus infection. There is a danger that their ability to control their neuromuscular system, in particular fundamental abilities such as balancing flexors and extensors in the neuromuscular system may decrease dramatically in the long-term. If such polio survivors could improve their ability to balance, it would be possible for them to use the "Robot Suit HAL" wearable movement support device. HAL anticipates its wearer's intended movements through the measurement of bioelectrical signals, and generates assistive torques to support their movements. This study proposes a biofeedback training method using visual information, with the objective of restoring motor functions using HAL. A biofeedback system that feeds-back bioelectrical signals visually was developed, and tested with a polio survivor. The polio survivor was able to adjust the balance of their muscular control through the proposed training method, and voluntary motion was recorded to a paralyzed knee using a single-joint type HAL. These results suggest that polio survivors who have been paralyzed for a long time may improve their ability to control their neuromuscular system by using the proposed training method.
著者
星川 秀利 藤本 浩志
出版者
一般社団法人 日本機械学会
雑誌
日本機械学会論文集 C編 (ISSN:03875024)
巻号頁・発行日
vol.69, no.680, pp.1080-1085, 2003-04-25 (Released:2008-02-26)
参考文献数
12

The purpose of this study is to investigate the influence of lower saddle height on the knee joint. Five healthy male pedal at 60 rpm against the work load of 100 and 200 W. Three saddle heights of 80, 90 and 100% of trochanteric leg height are selected in this study. During each trial, the position data of the right lower limb's joints by the video camera and the force data of the right pedal by the force sensor are measured. Using these data, the inverse dynamics analysis is done, and the following results are obtained. The peak link force acting on the knee joint and the peak knee extension moment do not indicate any change over the three saddle heights, however, the angles at their peak values shift to the knee flexion as the lower saddle height. These results indicate that the lower saddle would overload at the knee joint.
著者
藤本 浩志 加藤 一郎
出版者
一般社団法人 日本機械学会
雑誌
日本機械学会論文集 C編 (ISSN:03875024)
巻号頁・発行日
vol.61, no.582, pp.641-646, 1995-02-25 (Released:2008-02-26)
参考文献数
8
被引用文献数
1 1

This paper deals with the method of controlling an A/K prosthesis which allows disabled persons to ascend a staircase. Since conventional A/K prostheses are capable of only the function of walking on a level surface, disabled persons wearing conventional A/K prostheses have been compelled to walk on stairs with unnatural posture. The research study of developing powered A/K prostheses has the important themes of not only developing the mechanism of the prosthesis but also devising the controlling method. By measuring the axial forces acting on the socket ; which is the man-machine-interface, during walking, using the six axis force-moment sensor, the torque of a disabled side hip joint was calculated. We devised the control method using this torque as the control signal. Results of clinical walking experiments showed that a subject wearing the A/K prosthesis was able to walk with a joint angle pattern similar to that of unaffected persons. Furthermore, from the results of the inverse dynamics analysis, the subject was found to generate a similar torque pattern and power pattern at his disabled side hip joint. Thus the effectiveness of the controlling method proposed in this study was confirmed.
著者
小出 祐一 中川 正紀 福士 直己 石垣 博邦
出版者
一般社団法人 日本機械学会
雑誌
日本機械学会論文集 C編 (ISSN:03875024)
巻号頁・発行日
vol.73, no.725, pp.66-71, 2007-01-25 (Released:2011-03-04)
参考文献数
9
被引用文献数
1

In vibration design, we need to estimate the damping ratio to calculate the dynamic response of a structure. In particular, an estimation of its probability distribution is important to carry out so-called probabilistic design. For this paper, we developed an estimation method using the Bayesian approach to generate the probability distribution of the damping ratio from a vibration test with a small sample size. The Bayesian approach has special significance to engineering design, where available test data is invariably limited, for the approach can systematically incorporate subjective judgments based on experience or indirect information with observed data. We supposed that the probability distribution of the damping ratio has a normal distribution. Therefore, we applied the Bayesian approach to estimate unknown parameters of the distribution. In addition, we compared this method with a method of moments classified as a classical estimation and investigated the influence of sample size by conducting an evaluation test. With the results of our analysis, we came to the following conclusions. First, he true standard deviation of the damping ratio is less than 0.4, and the prior distribution of the standard deviation ranges between 0 and 0.5. (1) The estimated probability distributions determined by the Bayesian approach and the classical approach almost fully agree across more than 40 specimens. (2) The Bayesian approach provides good agreement, less than 10 percent error, with a true standard deviation for approximately 10 specimens. Even though the prior distribution of standard deviation ranges between 0 and 1.0, almost the same accuracy is obtained for approximately 10 specimens.
著者
斉藤 俊 千葉 洋三
出版者
一般社団法人 日本機械学会
雑誌
日本機械学会論文集 C編 (ISSN:03875024)
巻号頁・発行日
vol.64, no.623, pp.2389-2394, 1998-07-25 (Released:2008-02-26)
参考文献数
10

Two kinds of road racer bicycles are employed to research vibration characteristics of driving bicycles. After obtaing the natural frequencies and modes by vibration test in the non-driving state, practical driving tests are carried out. The acceleration of vibration in the middle of the handles and under the saddles are measured and the corresponding spectral density functions are calculated based on FFT method. The results show that in the driving bicycles, the dominant frequencies exist between 10 Hz and 50 Hz and the lower two modes in the non-driving state are excited.
著者
中村 友道 廣田 和生 友松 健一 高井 睦夫 岩瀬 敏彦 宇和川 誠一 班目 春樹 岩壺 卓三 齋藤 孝基
出版者
一般社団法人 日本機械学会
雑誌
日本機械学会論文集 C編 (ISSN:03875024)
巻号頁・発行日
vol.68, no.668, pp.1064-1072, 2002-04-25 (Released:2008-02-26)
参考文献数
7
被引用文献数
1 1

A partial but full-size mock-up test of practical steam-generator U-bend tubes in nuclear power plants has been carried out, where the test model has been set in a HFCF-123 fluid two-phase flow loop. U-bend tubes are supported with so-called "Anti-vibration Bars (AVB) ", which have two types of AVBs in Japan, 7-span type and 5-span one. Both types of AVBs have been examined and it is found that tubes with AVB supports shows no large amplitude vibration up to 150% flow rate to the practical condition. Basic data for the fluidelastic instability are obtained when some tubes have been set to be flexible at some contact points with AVBs.
著者
永瀬 和彦 橋 弘矩
出版者
一般社団法人 日本機械学会
雑誌
日本機械学会論文集 C編 (ISSN:03875024)
巻号頁・発行日
vol.74, no.744, pp.1938-1947, 2008-08-25 (Released:2011-03-04)
参考文献数
26
被引用文献数
1

The friction coefficient μ on the contact point position between a wheel flange and a rail is said to seriously affect on the occurrence of the wheel-climb derailment. However, the method to quantitatively and exactly evaluate the μ has not suggested until to the present. The authors proposed a method to easily and exactly evaluate the value, and made it clear by an experiment, employing a 1/5 scale model track and model truck. The result obtained through the experiment indicates that the value on dry rails has a similarity with that of the adhesion coefficient, and that the dry rail on the main line keeps the value at high level. Using the μ value obtained by the studies, the risk of the wheel-climb derailment was evaluated. As the result of the evaluation, they found that higher μ value than the conventionally used one should be introduced for the risk evaluation of the derailment, and that very short term lateral force below 60 ms should be observed on the steep curvatures.
著者
古林 卓嗣
出版者
一般社団法人 日本機械学会
雑誌
日本機械学会論文集 C編 (ISSN:03875024)
巻号頁・発行日
vol.66, no.641, pp.306-313, 2000-01-25 (Released:2008-02-26)
参考文献数
12
被引用文献数
1 1

A numerical study of self-acting gas-lubricated wave journal bearings is presented for their dynamic performances : HFW(self-excited half-frequency whirl)stability and dynamic response of an out-of-balance rotor. The study is conducted under practical operating conditions by means of a nonlinear orbit approach. Numerical examples of wave bearings are compared with those of herringbone-grooved bearings, and it is found that wave bearings give relatively favorable dynamic performances. Considering both HFW stability and dynamic stiffness, three-wave bearings are recommended for a practical use. However, it should be pointed out that HFW stability of wave bearings is quite sensitive to the wave amplitude, and also the synchronous orbit geometry of an unbalanced rotor supported on a wave bearing can be complicated out of plain circle.
著者
古林 卓嗣
出版者
一般社団法人 日本機械学会
雑誌
日本機械学会論文集 C編 (ISSN:03875024)
巻号頁・発行日
vol.62, no.604, pp.4636-4643, 1996-12-25 (Released:2008-02-26)
参考文献数
20
被引用文献数
1 1

A multigrid method has been introduced as a fast alternative to conventional relaxation methods for obtaining a solution to the Reynolds equation for self-acting gas-lubricated bearings. This paper verifies the procedure applied to both static and time-dependent dynamic analyses of plain-cylindrical journal bearings. The method gives successful results with less computational effort compared with single grid-oriented iterative methods. In addition, the new approach does not require a trial and error process to optimize the overrelaxation parameter unlike a successive overrelaxation method. The nonlinear orbit method which is an accurate but time-consuming transient analysis is expected to be reduced to a handy design tool for a complicated bearing system on incorporating the multigrid technique.
著者
古林 卓嗣
出版者
一般社団法人 日本機械学会
雑誌
日本機械学会論文集 C編 (ISSN:03875024)
巻号頁・発行日
vol.65, no.629, pp.330-336, 1999-01-25 (Released:2008-02-26)
参考文献数
12
被引用文献数
1 1

Both experimental and numerical studies are conducted on half-frequency whirl (HFW) stability of axially-grooved self-acting gas-lubricated journal bearings. The studies demonstrate that 8-grooved bearings are unconditionally unstable with usual bearing clearance and rotational speed. On the other hand, 2 grooved bearings operate stably at relatively low values of bearing number which are obtained with usual clearance and speed. The physics of HFW stability is attributed to the pressure distribution geometry. Further, as a result of extensive numerical simulations, it is found that 3 grooved bearings with groove width ratio to total width of 0.3 through 0.5 give favorable stability performance.
著者
岡本 和也 山口 健吾 丸 典明
出版者
The Japan Society of Mechanical Engineers
雑誌
日本機械学会論文集 C編 (ISSN:03875024)
巻号頁・発行日
vol.72, no.718, pp.1840-1847, 2006
被引用文献数
2

We propose a method for following motion control of the mobile robot by using Linear Visual Servoing (LVS). Following motion control is realized by the following motion of the body to the target object keeping a desired distance. Following motion control by using LVS is based on linear approximation of the transformation between binocular visual space and motion space of the mobile robot. Motion space is defined by translational velocity and rotational velocity of the robot coordinate system which is attached at the center of gravity of the mobile robot. Some experimental results are presented to demonstrate the effectiveness of the proposed method.
著者
川副 嘉彦 武田 幸宏 中川 慎理
出版者
一般社団法人 日本機械学会
雑誌
日本機械学会論文集 C編 (ISSN:03875024)
巻号頁・発行日
vol.76, no.770, pp.2646-2655, 2010-10-25 (Released:2017-06-09)
参考文献数
18
被引用文献数
1 1

There has been no question that some strings do provide a better grip than others, but that did not guarantee that the ball will produce more spin. Furthermore, experiments with hand-held rackets has been needed to solve the vexed question of how players can tell the difference between different strings when laboratory tests indicate that they should play the same. The previous paper of the authors made clear the mechanism of top spin performance in actual tennis and its improvement by lubrication of notched nylon strings according to the high speed video analysis on the court for the first time. It succeeded in an experiment showing that as the main strings stretch and slide side ways more, the ball is given more spin due to restoring force parallel to the string face when the main strings spring back and the ball is released from the strings. Since the notches of strings decrease spin rate, the lubricant materials are effective to the notched strings. Furthermore, it showed that the more spin results in the reduction of shock vibrations of the wrist joint during impact. This paper showed that the ball is given less spin rate (40% decrease) with the notched used strings compared to that with the new strings in the case of the nylon in this experiment, which has remained to be seen which gives more spin between new strings and the lubricated used strings, and it showed that the ball is given more extra spin (30% increase) by oil lubrication at the string intersections compared to that with the notched used nylon strings. Furthermore, it also showed that the used natural gut with notches decrease 70% of spin rate compared to the new natural gut without notches in the another experiment, which has remained to be seen whether the same results will be obtained. It also showed the difference of the topspin behavior when a pro and an amateur hits a ball.
著者
川副 嘉彦
出版者
一般社団法人 日本機械学会
雑誌
日本機械学会論文集 C編 (ISSN:03875024)
巻号頁・発行日
vol.58, no.552, pp.2467-2474, 1992-08-25 (Released:2008-02-26)
参考文献数
3
被引用文献数
2 3

There are a number of unclarified points regarding the impact phenomena and the optimum design of tennis rackets. The present study is based on the idea that the dynamics of a racket consists of the dynamics of a rigid body with an arm swing given at a grip as a boundary condition, an impact between a ball and strings with racket frame as an input force, and the structural vibration of the racket. In this paper, impact force and impact duration are investigated, considering the strong nonlinearity of the restoring force of ball and strings. Furthermore, the coefficient of restitution of the tennis racket is estimated using a personal computer on the basis of the impact phenomena and the experimental modal analysis. In order to predict the contact duration, which has an influence on the racket vibration, a simple impact model has been proposed, i.e., that the contact duration is determined by the natural period of a whole system composed of the mass of the ball, the stiffness of the ball and strings, and the reduced mass of the racket at the impact point on the racket face. The calculated results agree fairly well with the experimental results.