著者
岡田 昌史 黒須 寛明
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 (ISSN:21879761)
巻号頁・発行日
vol.88, no.906, pp.21-00317, 2022 (Released:2022-02-25)
参考文献数
12
被引用文献数
1

Because mechanical parts will be broken by high acceleration caused by impact of collision, a shock reduction mechanism takes an important role for mechanism design. Springs and dampers have been often used for a shock absorber, however, because of their mass, the impact is transmitted to the body. Momentum exchange impact damper (MEID) and mechanical singularity will be effective mechanism design. The former transfers momentum from body to damper-mass to reduce the body velocity. The latter avoids impact transmission. This paper proposes an impact mitigation mechanism inspired by break-fall in Judo. The mechanism exchanges momentum without additional sensor nor actuator, and avoids impact transmission by singular configuration. It is shown that the proposed mechanism has 1-DOF by Kutzbach-Gruebler’s equation using a planer model and two singular configurations by singularity analysis. Dynamics simulation confirms the concept of the proposed mechanism (Momentum exchange). And a prototype is designed and motion captured by a high speed camera to evaluate the momentum exchange.
著者
村井 聡紀 土屋 茉由 穂苅 真樹
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.2013, pp._J231011-1-_J231011-5, 2013

In general, bat swing analysis of baseball has adopted an optical motion capture system. It is possible to perform advanced operating analysis, but the system is not practical for large-scale, high cost and labor-consuming measurement. In this study, the trunk rotation movement in baseball bat swing was measured using a three-dimensional gyro sensor. Gyro sensor attached to the shoulder and waist, to measure the angular velocity of the vertical axis of the body. It was possible to show a rotation movement of the trunk during the bat swing similar to the DLT method. There was no significant correlation between the angular velocity of the trunk and swing speed. There was a significant positive correlation between the maximum angular velocity of the waist and maximum angular velocity of the shoulder (r = 0.66). As a result, it was to clarify the relationship of the swing speed and trunk rotation movement.
著者
熊谷 正朗 玉田 薫
出版者
一般社団法人 日本機械学会
雑誌
ロボティクス・メカトロニクス講演会講演概要集 2007 (ISSN:24243124)
巻号頁・発行日
pp._2A1-J02_1-_2A1-J02_4, 2007-05-11 (Released:2017-06-19)
被引用文献数
1

The Roller-Walk is one of methods for locomotion of walking robots. It requires only passive wheel(s) on each of legs, and periodic motions of legs generates driving force. Successful results were shown in quadruped robot, and some trials had also been carried out on biped robot. The biped roller-walk had a problem in following trajectories because its 'skate' tends to go straight while trajectory curves. This paper proposed one of successful method for biped roller-walk. The robot use a special type of trucks whose curvature can be changed only by inclining the body of the truck. The experiments showed effectiveness of our mechanism in roller-walk on straight, right turn, and left turn trajectories.
著者
金子 淳一 細矢 直基 古屋 耕平
出版者
一般社団法人 日本機械学会
雑誌
Dynamics & Design Conference 2010 (ISSN:24242993)
巻号頁・発行日
pp._111-1_-_111-6_, 2010-09-14 (Released:2017-06-19)
被引用文献数
2 4

This paper discuses the way to reduce the noise and vibration of thin plate structures. This paper focuses on the musical saw, a kind of musical instrument. The musical saw is thin plate and it is need to bend the saw as S-curve, to play the instrument. Thin plate structures used for various products. In some case, curvature is laid on thin plate structures to enhance the rigidity. If musical saw and thin plate structures conditions are matched, it will be noise problem. Investigating that the relationship between the sound pressure, S-curve, boundary condition, and aspect ratio of the saw by experiment and FEA, it is discussed to apply the investigation result to the thin plate structures.
著者
戸田 均
出版者
一般社団法人 日本機械学会
雑誌
年次大会 2013 (ISSN:24242667)
巻号頁・発行日
pp._S113024-1-_S113024-3, 2013-09-08 (Released:2017-06-19)

To prevent the wheel separation accidents, clarifying the influence of running condition on load of wheel bolts. In this paper, I investigated the stress of wheel bolts while the vehicle is moving. In the results, I confirmed that stress amplitude on left rear wheel bolts increased in the car trun to the right. Then the load of wheel bolts changed the pulsating bending load from the reversed bending load with loosing the wheel bolt.
著者
奥村 幸彦 渡部 弘達 岡崎 健
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B編 (ISSN:18848346)
巻号頁・発行日
vol.79, no.799, pp.465-476, 2013 (Released:2013-03-25)
参考文献数
31
被引用文献数
1 1

The purpose of this study is to clarify the fundamental and general features of N2O formation during the combustion of pulverized biomass under low temperature. First, the effect of various important factors, i.e., combustion temperature, volatilization process (i.e., either slow or rapid dispersion), and nitrogen content in biomass on N2O formation were investigated by numerical analysis. The analysis of the effect of combustion temperature on the formation of nitrous oxide showed that N2O emission level increases with the decrease in combustion temperature, and both N2O and NO levels are strongly dependent on the combustion temperature. In other words, there is a trade-off relationship between the formation of NO and that of N2O. The analysis of the effect of the slow/rapid volatilization process on the formation of nitrous oxide showed that the conversion ratio of biomass-N to N2O increases with the decrease in the dispersion of volatile matter per unit time; it means that biomass-N is effectively converted to N2O during slow volatilization. Further, the gasification reactions among CO2, O2, and C occur simultaneously on the surface of biomass particles during combustion. With respect to the effect of nitrogen content in biomass, the N2O emission level increases with the increase in N-content of the biomass, while the NO emission level remains constant during low-temperature combustion.
著者
遠藤 大地 鶴田 佳宏 山縣 雅紀
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.2020, 2020

<p>The probable performance distribution in an orbit environment of a power supply of micro/nanosatellites was evaluated by electrochemical measurements using hundreds of commercial cylindrical lithium-ion batteries (LIBs). According to the distribution map of the initial characteristics, there were 3% distribution in the discharge capacity and 11% in the internal resistance. Despite careful selection of LIB cells having same initial characteristics from the above-mentioned distribution map, the large differences in discharge capacity were found at relatively high current density with low temperature of 0°C, where the batteries installed in the CubeSats experiences. Although the difference in low-temperature performance of LIB cells fairly depended on their internal resistance, causeless factors affecting the exothermic behavior in the cooled batteries at its early stage of discharging, which leads higher or lower discharge capability, were observed. Such characteristic behavior may cause deterioration of the performance of the power supply module, overcharge/over-discharge failures, and cause safety hazard of the satellites, especially CubeSats.</p>
著者
松永 信智 坂本 将一 田中 友樹 岡島 寛
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 (ISSN:21879761)
巻号頁・発行日
vol.84, no.858, pp.17-00349, 2018 (Released:2018-02-25)
参考文献数
19
被引用文献数
1 1

Recently, electrical welfare vehicles driven by two motors employing free casters are widely used by patients and elders. However, as the user is not able to drive the vehicle well on the uneven rough roads, it is necessary to apply a new mechanism to drive on the rough road in order to expand driving area. The skid steer vehicle (SSV) has been used because of its high traveling ability on the rough road. However, the SSV has disadvantage that is, the driving assistance is required because its steering is highly affected by the road condition. The aim of this study is to design a driving assistance system of SSV for patients and elders by using Model Error Compensator (MEC) that suppresses the modeling error. The proposed controller consists of MEC, Extended Kalman Filter (EKF) that reduces sensor noise and system noise, and estimator of on-line cornering power of SSV. The effectiveness of the proposed system using on-line cornering power estimator is confirmed by the outdoor driving experiments. And the improvement of the driving assistance is evaluated by the correlation of the joystick manipulation comparing the paved and the dirt roads.
著者
土屋 和雄 渡辺 誠治 山田 克彦
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.549, pp.1366-1370, 1992-05-25 (Released:2008-02-26)
参考文献数
6
被引用文献数
1 2

This paper deals with a mathematical model of the mechanics of rigid bodies connected by rotary joints. The method is based on the Lagrangian formulation. The kinetic energy is written in terms of the angular velocities. The expression for the kinetic energy has a homogeneous quadratic form in the angular velocity, the coefficient matrix of which is given by the products of triangular matrices. The equations of motion are derived from the Lagrange's equations for the quasi-coordinates, the angular velocities of the bodies. The equations of motion become recursive forms due to the structure of the expression of the kinetic energy of the system. The algorithm of the inverse dynamics, which follows from the equations of motion, becomes also a recursive form like the algorithm based on the Newton-Euler equations of motion. Since the algorithm is based on the Lagrangian formulation, it can be extended to more complex systems that include flexible bodies, the constraints of which limit the motion of the systems, and so on.
著者
棚本 悠太 綿貫 啓一 楓 和憲 村松 慶一
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.2019, 2019

<p>The purpose of this study is to estimate the condition of second-hand goods from images using machine learning methods. Assuming that the condition evaluation of second-hand goods has a relationship with the damage that exists in them, we proposed and verified a method to estimate the condition of second-hand goods based on information of the damage. In this study, we chose men's dress shoes for condition evaluation and chose four types of damage: wrinkles, worn out of heel, dirt on outsole, dirt on inside as damage considered to be related to condition evaluation. (1)We create a CNN model that determines the presence or absence of damage, and (2) create a classification tree model that evaluates the state of the product from information on the presence or absence of damage and (3)We evaluated the condition of second-hand goods by combining two created models. As a result of verification, it was shown that the proposed method could evaluate the condition of used goods.</p>
著者
藤田 和央
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 B編 (ISSN:03875016)
巻号頁・発行日
vol.70, no.700, pp.3038-3044, 2004-12-25 (Released:2011-03-03)
参考文献数
7
被引用文献数
3 14

The air-breathing ion engine (ABIE) is a new type of electric propulsion system to be used to compensate the aerodynamic drag of the satellite orbiting at extremely low altitudes. To save the propellant mass for a long operation lifetime, it inhales the low-density atmosphere surrounding the satellite and use it as the propellant of ion engines. Since feasibility and performance of the ABIE depend strongly on the compression ratio and the air-intake efficiency, numerical analysis has been performed by means of the direct-simulation Monte-Carlo method to clarify the characteristics of the air-intake performance in highly rarefied flows. Influences of the flight altitude, the aspect-ratio of the air-intake duct, and the angle of attack are investigated.
著者
足立 高弘 合志 洋介 上原 春男
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 B編 (ISSN:03875016)
巻号頁・発行日
vol.68, no.672, pp.2232-2239, 2002-08-25 (Released:2008-03-28)
参考文献数
16
被引用文献数
2 2

Transitions and pressure drop characteristics of flow in periodically grooved channel are numerically investigated by using finite difference method. The channels consist of fundamental channel elements which have concave or convex rectangular grooves on the smooth plate. The flow fields are assumed to be two-dimensional and to be periodically fully developed. We have examined the effect of combination of the fundamental channel elements on transitions and pressure drop characteristics. The critical Reynolds numbers where a steady state flow bifurcates to a self-sustained oscillatory flow and the corresponding frequencies are evaluated for the combined channels. It is found that the self-sustained oscillatory flow occurs as a result of Hopf bifurcation. As for the pressure drop characteristics, it is found that the pressure drop for the combined channel which consists of elements with concave and convex grooves takes a middle value between the channel of concave elements and that of convex ones.