日本機械学会論文集 C編
Online ISSN : 1884-8354
Print ISSN : 0387-5024
68 巻 , 668 号
選択された号の論文の42件中1~42を表示しています
  • 板倉 和則, 須田 量哉, 奥野 守人
    2002 年 68 巻 668 号 p. 1027-1035
    発行日: 2002/04/25
    公開日: 2008/02/26
    ジャーナル フリー
    This paper presents a method for a numerical analysis of free vibration behavior of thin cylindrical panel with a curved principal axis on a plane, using finite element method with a triangular plate element; together with some numerical results. The method is based on accurate strain-displatement relationships in general thin shell theory, using a curvilinear coordinate system. Numerical results are compared with those in the literature, and those obtained by isoparametric shell element method. The comparison shows the method presented in this paper is useful for analyzing free vibration of thin cylindrical panel with a curved principal axis on a plane.
  • 浦田 喜彦
    2002 年 68 巻 668 号 p. 1036-1041
    発行日: 2002/04/25
    公開日: 2008/02/26
    ジャーナル フリー
    This paper deals with analysis of bending vibration of plates excited by concentrated forces and related problems. These problems have been treated by the finite element method, the finite difference method and the method of series expansion so far. However, these methods are not necessarily adequate to the present problems, because they cannot express exactly singularities due to concentrated forces. Analytic solutions including particular solutions corresponding to concentrated forces are used in this study. Boundary conditions are satisfied approximately by the collocation method. This method can be applied to not only forced vibrations but also free vibrations of a plate supported at several points. A class of arbitrarily shaped plates can be analysed by the proposed method.
  • 堀内 敏彦, 井上 雅彦, 今野 隆雄
    2002 年 68 巻 668 号 p. 1042-1048
    発行日: 2002/04/25
    公開日: 2008/02/26
    ジャーナル フリー
    The hybrid vibration experiment, in which an actual model of part of a vehicle excited by an actuator and vibration analysis of a numerical model are simultaneously conducted by exchanging information with each other, is being developed and tested. We have applied this experimental method to the vibration analysis of a suspension vehicle system excited by a roadsurface pattern. By using a quarter model of a vehicle with two degrees of freedom, we established an experimental system that consists of a hydraulic actuator which excites the suspension, a digital signal processor which calculates the response of the numerical model and generates reference signals for the hydraulic actuator, and a load cell which measures the reaction force of the suspension. We did trial tests on this experimental system and found its simulated results agree well with corresponding experimental measurements.
  • 篠原 雄一郎, 清水 信行, 梶原 浩一, 小川 信行
    2002 年 68 巻 668 号 p. 1049-1055
    発行日: 2002/04/25
    公開日: 2008/02/26
    ジャーナル フリー
    This paper describes the experimental study of suppression control of sloshing during table test of liquid tanks. Quick sloshing motion suppression has been proposed by means of post-control for shaking table experiment. Use of shaking table for suppressing sloshing motion which grows in the main sloshing experiment does not require any additional experimental devices. H control algorithm has been applied for the sloshing suppression table motion control. The experimental verification has been demonstrated by using a 1-D Large Scale Shaking Table of National Institute for Earth Science and Disaster Prevention in Tsukuba.
  • 箕輪 親宏, 清水 信行, 鈴木 純人
    2002 年 68 巻 668 号 p. 1056-1063
    発行日: 2002/04/25
    公開日: 2008/02/26
    ジャーナル フリー
    In 1995 Hyogo-ken Nanbu Earthquake, many rectangular water tanks were damaged. Rectangular water tanks are mainly produced by fiber reinforced plastic (FRP) panels or stainless steel panels in Japan. Though there have been conducted many seismic tests on FRP panel tank, few tests on stainless steel panel tanks. In conjunction with this, the shaking table tests of two different types of stainless steel panel tanks were conducted. One was the column reinforced tank. The other was the tie beam reinforced tank. From the shaking table test results, the column reinforced type tank was found to be superior in the characteristic of self standing than the tie beam type tank, thus the superiority of seismic performance of the column type was shown. The measured water pressure data were compared and discussed with the existing design formula and the potential theory calculation.
  • 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
    2002 年 68 巻 668 号 p. 1064-1072
    発行日: 2002/04/25
    公開日: 2008/02/26
    ジャーナル フリー
    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.
  • 中村 友道, 鈴田 忠彦, 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
    2002 年 68 巻 668 号 p. 1073-1079
    発行日: 2002/04/25
    公開日: 2008/02/26
    ジャーナル フリー
    This report (3rd Report) shows an advanced estimation method of the fluidelastic instability for the U-bend tube bundle of steam generators in Japan, which is subjected to steam-water two-phase flow. The criterion is based on the usual Connors' formula, where many parameters are estimated with newly measured data and with an advanced thermo-hydraulic code (shown in 1st Report). Some measured data, which are required for the criteria, are shown here, added to the critical factor (shown in 2nd Report). Safety margin is introduced for the design to avoid the severe damage, compared with measured U-bend instability and an example of a practical event.
  • 吉田 豊美, 高木 亨之, 岡部 明, 松下 修己
    2002 年 68 巻 668 号 p. 1080-1087
    発行日: 2002/04/25
    公開日: 2008/02/26
    ジャーナル フリー
    For estimating the vibration of rotating shafts like turbine-generator sets, the rotor vibration analysis must include the vibration characteristics of the foundation. In this paper we propose a method of analyzing the vibration of a coupled rotor-foundation system. This is a quasi-modal technique based on the same concept as the well-known modal synthesis method. It provides a reduced model of an actual system using a combination of eigen modes of an inner system restricted at the bearings plus deflection modes created when inputting the load at the boundary points. A rotor system and a foundation system are each reduced using this quasi-modal technique, and the reduced models are then coupled at the bearing boundary points. Through this procedure, we developed computer code for the vibration analysis of the whole system. This code was applied to a simple model consisting of a rotor and a foundation system using several parameters. The calculated results of this coupled system proved the effectiveness of this code.
  • 小泉 孝之, 辻内 伸好, 柴山 俊之, 家辺 健吾, 山崎 浩二
    2002 年 68 巻 668 号 p. 1088-1095
    発行日: 2002/04/25
    公開日: 2008/02/26
    ジャーナル フリー
    This paper describes an identification method of the dynamic characteristics in consideration of the dependency of amplitude and frequency, followed by the vibration analysis of rigid body supported with hydraulic engine mounts. At first the parameters to describe the dynamic characteristics of hydraulic engine mount, unable to be measured directly, are predicted. The identified results agree well with measured values. The amplitude range which hydraulic mount features high damping coefficient was investigated. Secondary, the steady-state response analysis of rigid body supported by the hydraulic mounts was performed. The validity was confirmed by the excitation experiment.
  • 小野 京右, 右手 潤二, 中島 求
    2002 年 68 巻 668 号 p. 1096-1103
    発行日: 2002/04/25
    公開日: 2008/02/26
    ジャーナル フリー
    Snake-like animal locomotion by means of friction force can perform many kinds of motion and body shape. We have proposed the method of locomotion based on self-excitation principle in order to realize the high speed and high efficiency locomotion. In this study, we applied the self-excited locomotion to a snake mechanism. First we analyzed the kinematics and the dynamics of a three link snake mechanism driven by the self-excitation. Then we manufactured a prototype of a snake robot. By experimental identification of the traction parameters of the robot, we showed a good agreement between the experimental and simulated results and a high locomotion velocity of 0.4[m/s]. We further showed the high efficiency of the self-excited snake locomotion.
  • 小林 宏, 菊池 耕生, 小野木 佑, 越智 一広
    2002 年 68 巻 668 号 p. 1104-1112
    発行日: 2002/04/25
    公開日: 2008/02/26
    ジャーナル フリー
    Sensor-based navigation is one of the most important researches for mobile robots domain and there are many research works for sensor-based navigation. We propose the insects inspired landmark navigation to pinpoint the target position in this paper. There exit several research works such as snapshot model and average landmark model which require the absolute bearing information (compass) and visual one. Whereas our method called relative angle model (RAM) needs only visual information which needs relative positions of 3 landmarks. By simulation and experiment using 3D blimp-type flying robot, we find that the pinpoint 3D navigation works out well by RAM.
  • 小島 広久, 向井 拓幸
    2002 年 68 巻 668 号 p. 1113-1118
    発行日: 2002/04/25
    公開日: 2008/02/26
    ジャーナル フリー
    Attitude synchronization is a key technology to facilitate the capturing process of tumbling satellites. Tumbling motion of the satellites is a nonlinear system and the inertia ratio of the satellite is a dominant parameter of the motion. Estimation of the inertia ratio of the tumbling satellites is thus important function for a chaser satellite to synchronize its attitude motion with the tumbling satellite motion. The present study is devoted to investigate an adaptive sliding mode control (ASMC) algorithm applied to attitude tracking maneuvers. The adaptive law added to the sliding mode control (SMC) algorithm is employed to estimate the inertia ratio of the tumbling satellite. Attitude tracking performances of the ASMC method is studied numerically to compare with those of a quaternion feedback control method and a simple SMC method. It is shown that the precise synchronization can be executed by the ASMC method even if there exist some errors between the real value of the inertia ratio of the tumbling satellite and the estimated one at the beginning of tracking maneuvers.
  • 小島 広久, 荒井 直広
    2002 年 68 巻 668 号 p. 1119-1126
    発行日: 2002/04/25
    公開日: 2008/02/26
    ジャーナル フリー
    A drawback with feature based visual servoing is that some feature marks go off the screen in the case where goal positions for the feature marks are near the edges of the screen, unless the gain coefficients are adjusted appropriately. This paper proposes a method of compensating the feature based visual servoing with fuzzy control, instead of adjusting the gain coefficient. Input variables to the fuzzy system are: distance to the current position of the feature mark from the center of the screen, velocity of the feature mark and distance to the goal position from the current position of the feature mark on the screen. An output from the fuzzy system is a compensation value that prevents the feature marks from going off the screen. Fuzzy rules are designed in such a way that the compensation value becomes smaller, as the feature marks approach the goal position on the screen. Effectiveness of the proposed method is shown by numerical simulations.
  • 大川 不二夫, 本田 英己, 小林 順, 久保山 幸司, 小黒 龍一
    2002 年 68 巻 668 号 p. 1127-1132
    発行日: 2002/04/25
    公開日: 2008/02/26
    ジャーナル フリー
    This paper deals with a vibration and position control of a feed drive system, which is hindered by a vibration of the machine stand. The control scheme is designed based on a model following control method which can control the vibration of the machine stand without measurement a position of the stand. In order to assure good tracking performance as well as to guarantee robustness towards changes or uncertainties in the dynamics of the system, a discrete-time simplified model and a sliding mode control method are utilized for designing a robust controller. Experimental results demonstrate the good control performance and the effectiveness of the proposed control strategy
  • 神本 和昭, 川辺 尚志
    2002 年 68 巻 668 号 p. 1133-1139
    発行日: 2002/04/25
    公開日: 2008/02/26
    ジャーナル フリー
    The stabilizing control techniques for an inverted-double pendulum system consisting of an elastic link mounted on a rigid one have been investigated by employing a distributed-parameter modeling method taking the 2nd and 3rd vibration modes of the elastic beam as the residual modes, and by using both a sliding mode controller (SMC) designed on the basis of the H control theory and a conventional H servo controller to compare the robust performance. By applying the loop-shaped H control scheme to the design of the switching plane of SMC, the robust hyper-plane with both frequency characteristics and integral ones can be easily realized even to a multi-mode of flexible structure system having the jω poles such as the double pendulum system discussed here, and the effectiveness of the design is verified from the real system-experimental results that the H control based frequency-shaped SMC has not only the simultaneous suppression effect against the chattering and the spillover components, but also the cart positioning control without static error. Furthermore, it is found that the designed SMC system exhibits considerably robust performance against impulsively applied disturbances, and that the SMC system is robust as compared with the conventionally designed H controller system.
  • 細矢 直基, 吉村 卓也
    2002 年 68 巻 668 号 p. 1140-1148
    発行日: 2002/04/25
    公開日: 2008/02/26
    ジャーナル フリー
    Experimental modal analysis is a fundamental technique for the analysis of structural vibration. However FRF measurement on rotational degrees of freedom (DOFs) has been disregarded in the experiment because of the difficulties of measurements. Rotational FRFs are vital to extend the applicability of experimental modal analysis. The authors have proposed a measurement technique of rotational FRFs. It is important to evaluate the accuracy and reliability of estimated rotational FRFs. In this paper an improved method for the estimation of rotational FRF and the evaluation fuction of the reliability of rotational FRF are presented: The variance of rotational FRF is derived by considering the propagation of random noise in the measured FRF; and the Reliability Factor of estimated FRF is also obtained from variance. The effect of random noise in the measurement to the rotational FRF is investigated by numerical simulation and experimental application.
  • 中村 善也, 鷲尾 誠一, 庄司野 公也
    2002 年 68 巻 668 号 p. 1149-1156
    発行日: 2002/04/25
    公開日: 2008/02/26
    ジャーナル フリー
    Firstly, steady-state performance of an oil hydraulic poppet valve was experimentally studied with 6 different poppet-seat combinations. In order to obtain as much detailed data as possible, the poppet displacement as well as the pressure drop and the flow rate were accurately measured. The results completely supported the validity of the new empirical equation which the present authors have proposed for a constriction with a variable opening area; a product of the pressure drop and the square of the opening area is proportional to a quadratic of the flow rate. A dynamic model for the poppet valve was also formulated on the basis of the static characteristics. Frequency response tests revealed that there was undeniable discrepancy between the experimental values and the predictions by the dynamic model. Concerning the response between the pressure drop and the poppet displacement, the discrepancy indicates considerable damping exists in the poppet motion. Moreover that in the pressure drop-flow rate response suggests the unsteady characteristics of the poppet constriction cannot be predicted by the steady-state ones.
  • 谷本 隆一, 二宮 修, 朝倉 孝征
    2002 年 68 巻 668 号 p. 1157-1162
    発行日: 2002/04/25
    公開日: 2008/02/26
    ジャーナル フリー
    In recent years one-box-cars are very popular in the market. Hence their interior noise level is required to be the same as that of passenger cars. One of the problems to be solved is to develop reduction method for low-frequency booming noises caused by, for example, road shock. To reduce low-frequency booming noises after the design is completed requires modification of the car in a large scale. So the development of a noise reduction method applicable in an early stage of design is desired. In this paper, we analyzed the mechanism of the occurrence of road shock low-frequency booming noises of a newly developing one-box-car. We found that bringing the resonance frequency of the back door near to the resonance frequency of the bending mode of the car reduces the booming noises. Based on this result, we really could reduce the noises in the newly developed one-box-car.
  • 菊地 勝浩, 田中 靖幸, 吉田 康夫, 真鍋 克士
    2002 年 68 巻 668 号 p. 1163-1170
    発行日: 2002/04/25
    公開日: 2008/02/26
    ジャーナル フリー
    In using a microphone array to measure low frequency sound, it is not sufficient to assume plane wave incidence. First, this paper theoretically discusses the directivity of the microphone array in case the incident wave is spherical. When the incident wave is spherical, the directivity of the microphone array spreads. Then, a correction method is proposed to improve the directivity. This correction method is called a spherical wave correction method here. Next, in order to verify experimentally the validity of the spherical wave correction method, corresponding experiments were conducted. The experimental results were compared with the theoretical results and they were found to be in good agreement.
  • 川上 健作, 中部 昇, 大森 豪, 原 利昭
    2002 年 68 巻 668 号 p. 1171-1177
    発行日: 2002/04/25
    公開日: 2008/02/26
    ジャーナル フリー
    We evaluated the joint related to the arch of the foot to study the arch transformation pattern under different ankle position. Five fresh-frozen cadaveric lower legs were used. Each specimen was amputated at abous 150 mm from talocrural joint surface, and unnecessary dorsal soft-tissue of the foot excluding cardinal tendons was removed. The Direct Linear Transformation (DLT) technique was developed to determine three-dimensional motion of joints composed the arch of the foot during 0 (neutral) and 10 degrees dorsiflexion position under vertical load application. Results show that the arch transformation pattern at the neutral ankle position were planterfixion and eversion of calcaneus and dorsiflexion and eversion of transverse tarsal joint. In neutral position, cuneonavicular and tarsometatarsal joint motion were small. In ankle dorsiflexion, hindfoot and transverse tarsal joint were moved same pattern of the neutral position, cuneonavicular and tarsometatarsal joint motion were increased than neutral position.
  • 菅原 香織, 福永 久雄, 亀山 正樹, 胡 寧
    2002 年 68 巻 668 号 p. 1178-1184
    発行日: 2002/04/25
    公開日: 2008/02/26
    ジャーナル フリー
    This paper deals with an active vibration control of a laminated composite plate with piezoelectric actuators/sensors under dynamic loading. PVDF films are used as a modal transducer for identifying specific modes in vibration measurement, and PZT actuators are used as actuators of vibration control. An optimal control law for each control mode is applied to the vibration control of a cantilevered laminated plate. Numerical simulation on vibration control is performed for a cantilevered laminated plate based on a finite element analysis incorporating the stiffness and mass effect of actuators. The effectiveness of the present methodology is verified by several numerical examples.
  • 森 亮, 松田 健一, 金箱 秀樹, 岡田 養二
    2002 年 68 巻 668 号 p. 1185-1190
    発行日: 2002/04/25
    公開日: 2008/02/26
    ジャーナル フリー
    This paper proposes a new type of self-bearing motor which is intended for a multi-pole rotor to have both functions of rotary motor and magnetic bearings. First, the principle of the multi-pole self-bearing motor is explained. Then a simple experimental setup is made. In order to confirm the basic characteristics, the levitation force is measured which is proportional to the levitation current. Also the motoring torque is measured with the function of rotating speed. Finally, the levitated rotation test is carried out. The rotor can run up to 380 rpm without physical contact and has high rotating torque.
  • 疋津 正利, 関 啓明, 神谷 好承, 立矢 宏, 野村 久直
    2002 年 68 巻 668 号 p. 1191-1197
    発行日: 2002/04/25
    公開日: 2008/02/26
    ジャーナル フリー
    This paper discusses the high-speed intermittent motion by comparing the indexing cam- mechanism with the servo-system. The servo-system is generally composed of the position control system. The servo-system such as position control system generally contains the current limiter that is one of the non-linear elements. The intermittent motion generated by the position control system is frequently affected by the current limiter. On the other hand, the indexing cam mechanism has the problem of the distortion of the cam motion curve accompanied by its high-speed motion. The distortion of the cam motion curve is caused by the variation of speed that is led by the driving reaction. This paper presents a solution for the distortion of cam motion curve by giving the asymmetrical acceleration curve. As a result of this study, the distortion of the cam motion curve is improved by giving the longer deceleration time compared with the acceleration time.
  • 見浪 護, 鈴木 秀和, AGBANHA Julien
    2002 年 68 巻 668 号 p. 1198-1206
    発行日: 2002/04/25
    公開日: 2008/02/26
    ジャーナル フリー
    This paper presents a new method of scene recognition for manipulator real-time visual servoing, which utilizes a hybrid genetic algorithm (GA) in combination with a model shaping a target of known shape, and the unprocessed gray-scale image of a scene. The scene recognition method presented here is concerned with the simultaneous recognition of the shape and detection of the position and orientation in the two-dimensional raw-image, of a three-dimensional target being imaged. The proposed hybrid GA employs the "global" search feature of a two-point crossover of a GA, to search a target, together with a GA-based "local" search that focuses on the target of interest found so far, in order to detect accurate target's position in a short time by intensive searching. In order to appraise the proposed hybrid GA recognition method, experiments to pick up a natural fish swimming in a pool by hand net of a robot manipulator by using the visual servoing, have been conducted to show the performances with respect to recognition accuracy in time response and the real-time feature.
  • 平田 泰久, 初雁 卓郎, 小菅 一弘, 浅間 一, 嘉悦 早人, 川端 邦明
    2002 年 68 巻 668 号 p. 1207-1214
    発行日: 2002/04/25
    公開日: 2008/02/26
    ジャーナル フリー
    In this paper, we propose a concept of a human-robots cooperation system referred to as distributed robot helpers and a decentralized motion control algorithm of multiple mobile robot helpers for handling a single object in cooperation with a human/humans. The prototype system of distributed robot helpers referred to as DR Helper consists of an omni-directional mobile base, a six axis body force sensor, a folk lift, and an onboard controller. Each system is controlled by a kind of a damping motion control law using its own controller. Multiple DR Helpers transport a single object in cooperation with a human based on the operator's intentional force/moment. Experiments using two DR Helpers will illustrate the concept and show the validity of the proposed control algorithm.
  • 木口 量夫, 刈谷 臣吾, 渡辺 桂吾, 福田 敏男
    2002 年 68 巻 668 号 p. 1215-1222
    発行日: 2002/04/25
    公開日: 2008/02/26
    ジャーナル フリー
    We have been developing exoskeletal robots for human motion support. The exoskeletal robots enable physically weak people such as elderly people to take care of themselves. In this paper, we introduce an effective control method of a 1DOF exoskeletal robot for human elbow motion support. Multiple fuzzy-neuro controllers have been applied to control both the angular position and impedance of the exoskeltal robot system in any elbow angle based on force signals and biological signals that reflect the human subject's intention. Skin surface electromyogram (EMG) signals and the generated wrist force by the human subject during the elbow motion have been used as input information of the controller. The proposed system is able to adapt itself to the physiological condition of any human subject because of the adaptation ability of the fuzzy-neuro controllers. The experimental results show the effectiveness of the proposed control method of the exoskeletal robot.
  • 吉川 恒夫, 渡辺 哲陽, 大東 睦夫
    2002 年 68 巻 668 号 p. 1223-1230
    発行日: 2002/04/25
    公開日: 2008/02/26
    ジャーナル フリー
    Power grasp is a grasp that can hold objects stably without changing the joint torques of fingers. Almost all studies on power grasp deal with one object. But it is more efficient to hold and manipulate multiple objects at the same time. This paper derives a condition for power grasp for multiple objects. In this procedure, we discuss the set of the external force that can be resisted by only the constraints between objects. From the discussion, we derive the set of the external force that should really be resisted. We also define an optimal power grasp from the viewpoint of decreasing the work of joint torques, and derive the procedure. Lastly, we show some numerical examples to verify the validity of our approach.
  • 和栗 創一, 上中 玲子, 中島 尚正, 村上 存
    2002 年 68 巻 668 号 p. 1231-1238
    発行日: 2002/04/25
    公開日: 2008/02/26
    ジャーナル フリー
    To develop an automated microfactory system, a micro gripper to handle various-shaped works with large gripping force should be required. In this paper, a micro gripper using two-way shape memory alloy (TSMA) is designed. As the result, 28 [mm] size gripper to handle works of 5 [mm] diameter with more than 3 [N] gripping force is prototyped using TSMA plate of 0.45 [mm] thickness, 10 [mm] width, and 35 [mm] length. Optimization of TSMA configuration shows a possibility of an improved gripper design of 22 [mm] size and 20 [N] gripping force using currently available TSMA. Also, scale analysis shows the gripping force is in proportion to the square of scale parameter ε, and thus it indicates the gripper design of 1 [mm] size and 59 [mN] gripping force should be possible.
  • 高信 英明, 中澤 正幸, 高西 淳夫
    2002 年 68 巻 668 号 p. 1239-1244
    発行日: 2002/04/25
    公開日: 2008/02/26
    ジャーナル フリー
    This paper describes the quantification of mastication efficiency with a mastication robot. Although the conventional researches in the dental field calculate the mastication efficiency by using sieving test, ATP method and so on, these methods are affected by the saliva or subject's individual variation. The authors have tried to quantify the mastication efficiency with a mastication robot that was developed to simulate the human mastication from engineering viewpoint. Testing food was Tarnago-bolo that is popular food especially for the kids. The computation method for quantify the mastication efficiency was the sieving test that is usually used in the dental field. Experimental results with a mastication robot showed that the mastication efficiency increased like logarithmic function of chewing times.
  • 長谷 和徳, 大渕 修一, 堀江 徹
    2002 年 68 巻 668 号 p. 1245-1250
    発行日: 2002/04/25
    公開日: 2008/02/26
    ジャーナル フリー
    This paper describes a rehabilitation system to provide therapeutic exercise in order to prevent falls during walking in older adults. The rehabilitation system consists of a treadmill having two separate walking belts and a personal computer controlling the servomotors in the treadmill. Experiments were conducted in which falling perturbations were generated by suddenly and randomly reducing the speed of the walking belt on the left side. In the primary experiments, 10 young adults and 10 older adults were recruited, and electromyography data were collected during walking with falling perturbation. The reaction time of the musculus tibialis anterior in the non-perturbed leg in the older adults was significantly longer than in the young adults. The activation patterns in the electromyography data were characterized by a stepping reaction to control the posture. These results indicate that instability of walking in older adults may be caused by reduced functioning of the stepping reaction under dynamic balance control. It is believed that the proposed rehabilitation system may provide a novel therapeutic effect to prevent falling in older adults.
  • 山口 智実, 樋口 誠宏, 矢野 章成
    2002 年 68 巻 668 号 p. 1251-1256
    発行日: 2002/04/25
    公開日: 2008/02/26
    ジャーナル フリー
    Machining sounds has been told to be effective for monitoring of cutting tool conditions, but it has been difficult to avoid misunderstanding of the conditions in previous systems. There are two main causes. First, the peculiar sound to a condition dose not emanate continuously and an unexpected sound emanates occasionally. Secondly, in case of tool wear, the small difference between normal tool and tool wear makes the recognition of the wear hard. We propose the HSP (Hexadecimal Spectrum Pattern) as the definite expression of the spectrum patterns in this paper. And we also propose the new monitoring system by using the frequency of sound, which is applied by neural network, because we consider that the emanating time of the peculiar sound is as important as the spectrum pattern of it to recognize the condition exactly. In this system, cutting tool conditions, like normal, wear and fracturing, can be monitored without misunderstanding under a few cutting conditions.
  • 横山 良平, 島崎 雅弘, 伊東 弘一
    2002 年 68 巻 668 号 p. 1257-1264
    発行日: 2002/04/25
    公開日: 2008/02/26
    ジャーナル フリー
    To evaluate the performance of photovoltaic systems, it is necessary to estimate detailed characteristics of solar radiation which varies with seasons, time, and weather conditions. However, it is difficult to obtain detailed characteristics of solar radiation at an arbitrary location. The objective of this paper is to propose a method of estimating probabilistic characteristics of solar radiation at an arbitrary location, by combining rough data observed meteorologically at the location with detailed data measured at another location. The validity of the method is clarified by comparing the global solar radiation on the horizontal surface estimated and measured or observed meteorologically at some locations. The global solar radiation on the inclined surface is also estimated at the locations, and its features are clarified in relation to the weather conditions of the locations and the tilt angle of the surface.
  • 吉田 彰, 大上 祐司, 關 正憲, 荒瀧 拓之, 佐藤 雅靖, 烏野 勇
    2002 年 68 巻 668 号 p. 1265-1272
    発行日: 2002/04/25
    公開日: 2008/02/26
    ジャーナル フリー
    In order to investigate the influence of shot peening on the surface durability of sintered powder metal rollers, the plasma case-hardened sintered powder metal rollers shot-peened with different shot velocity, shot diameter and shot hardness were fatigue tested under a sliding rolling contact condition. The compressive residual stress, the hardness and the surface roughness of the rollers increased and the pores in those were deformed by the shot peening. The failure mode of the rollers was spalling. The failure depth of most rollers agreed almost with the depth near the case-core boundary where the amplitude A(τyz/HV) of the ratio of orthogonal shear stress to Vickers hardness became maximum. In these experiments the surface durabilities of strongly shot-peened rollers were lower than that of unpeened roller, on the other hand those of mildly shot-peened rollers were higher. The frictional force between the rollers and the shear stress below the contact surface generally increase as the surface roughness of the rollers increases. Therefore, it could be followed from above that the mild shot peening which dose not cause too large surface roughness should be selected in order to improve the surface durability of sintered rollers.
  • 中島 克洋, 高藤 和樹
    2002 年 68 巻 668 号 p. 1273-1278
    発行日: 2002/04/25
    公開日: 2008/02/26
    ジャーナル フリー
    Hydrostatic bearings are frequently adopted on precision machines because of their high bearing performance. However, still more improvement of the bearing stiffness is required to respond to the development of precision instruments. There exist already some methods to realize high bearing stiffness such as load dependent resistors so far. In this paper, we propose a new method to achieve the higher bearing stiffness with a simple mechanism. The principle of this arrangement is to perform the bearing clearance change by the land displacement in addition to the usual shaft displacement. The bearing structure is designed so that the land moves automatically depending on the bearing load change accompanied with oil pressure variation. The properties of this bearing are analyzed and a non-dimensional variable to lead to optimum bearing design and operating conditions is derived. With the bearing performance test, infinite bearing stiffness is confirmed between load carrying capacity of 0.4 to 0.9 under the non-dimensional variable of 1.15.
  • 東★ 康嘉, 矢野 昭彦, 松本 將, 秋月 幸男, 渡辺 真太郎, 梶原 哲雄
    2002 年 68 巻 668 号 p. 1279-1283
    発行日: 2002/04/25
    公開日: 2008/02/26
    ジャーナル フリー
    Oil in water emulsions have excellent cooling and fire resistance properties and are used as lubricants in cold rolling mills. The elastohydrodynamic lubrication (EHL) properties of O/W emulsions for cold rolling have not been confirmed clearly. For that reason, high pressure viscosity and film thickness were measured. From the results, the following facts were found. That EHL film could be formed and its thickness could be calculated using the high-pressure viscosity of O/W emulsions.
  • 趙 昌熙, 村上 輝夫, 澤江 義則, 坂井 伸朗, 三浦 裕正, 河野 勤, 岩本 幸英
    2002 年 68 巻 668 号 p. 1284-1290
    発行日: 2002/04/25
    公開日: 2008/02/26
    ジャーナル フリー
    The wear phenomenon of ultra-high molecular weight polyethylene (UHMWPE) in the knee and hip prostheses is one of the major restriction factors on the longevity of these implants. Especially in retrieved knee prostheses with anatomical design, the most predominant types of wear on UHMWPE tibial components are pitting and delamination. These fatigue wear of UHMWPE are believed to result from the repeated plastic deformation due to high contact stresses. In this study, elasto-plastic contact analysis of the UHMWPE tibial component based on geometrical measurement for retrieved knee prosthesis was performed using FEM to investigate the plastic deformation behavior in the UHMWPE tibial component. The results suggest that the maximum plastic strain below the surface is closely related to the subsurface crack initiation and delamination of the UHMWPE tibial component. The worn surface with improved geometrical congruity showed lower contact stress.
  • 関根 幸男, 三宅 正二郎, 渡部 修一
    2002 年 68 巻 668 号 p. 1291-1296
    発行日: 2002/04/25
    公開日: 2008/02/26
    ジャーナル フリー
    Carbon and boron nitride superlattice films were deposited by RF sputtering using two semicircular targets. Superlattice (C/BN)n films were deposited by controlling the opposing time of the substrate to each of the graphite and boron nitride semicircular targets. Micro-Vickers hardness, nanoindentation hardness and nanoscratching properties of these films were evaluated. Both micro-Vickers and nanoindentation hardnesses of the 4nm-period (C/BN)n multilayered film are the highest of all (C/BN)n films. Multilayered film of a suitable period has superior hardness and nanoscratching resistance. From the nanoscratching test evaluation, oscillatory scratching test, and ball-on-disk tribo test, the friction of the 4nm-period (C/BN)n multilayered film is lower than those of other (G/BN)n, carbon, boron nitride and carbon nitride films. The 4nm-period (C/BN)n multilayered films show the least damage and superior sliding endurance.
  • 栗田 恒雄, 近森 邦夫, 窪田 真一郎, 服部 光郎
    2002 年 68 巻 668 号 p. 1297-1302
    発行日: 2002/04/25
    公開日: 2008/02/26
    ジャーナル フリー
    Electrochemical machining (ECM) has an advantage of no tool wear. On the other side, it is difficult to carry out micro machining in ECM, because the electrode gap in ECM is large. In this paper, electrochemical micro machining with the developed electrode gap control system is demonstrated. The narrow gaps make the control of the process much more complex than normal ECM. Preliminary ECM experiments are carried out in order to investigate a proper condition of machining process. Small hole is machined by using a 0.2mm Ni rod. Drilling time and electrode gap is measured. An optimum machining condition of ECM is determined in terms of machining voltage, machining pulse length, amplitude of electrode for flushing out a contamination, and electrolyte concentration. After preliminary ECM experiments, three-dimensional micro machining is carried out under the optimum condition. First, prismatic electrode whose base is 200μm square is machined by ECM. Next, three-dimensional micro machining is carried out by scanning the prismatic electrode. Three-dimensional shape that is sub-millimeter order is successfully machined.
  • 畑中 伸夫, 山口 克彦, 高倉 章雄, 飯塚 高志
    2002 年 68 巻 668 号 p. 1303-1309
    発行日: 2002/04/25
    公開日: 2008/02/26
    ジャーナル フリー
    Cutting of a sheet metal by indentation of wedge shape punches is investigated as a process to achieve burr-free-cutting. Numerical simulations of the cutting process are done using a rigid plastic finite element code developed by the authors. Equivalent strain and hydrostatic stress distributions at the deformation region of the sheet are calculated, and the effects of wedge angle on the shape of the cut edge are discussed based on the calculated stress and strain states. To confirm the result of the finite element simulations, cutting experiments are carried out using a mild steel sheet of 3 mm in thickness, and the shape of the cut edge is observed using a scanning electron microscope. The experimental results show that the cutting mode depends very much on the wedge angle α and nose radius γ of punch; when the punch of γ=0.1mm and α=30 degree is used a sheet is separated by cutting, while when α=60 and 90 degrees ductile fracture is caused due to the secondary tensile force induced by the wedge indentation, and when α=120 degree brittle fracture is caused due to excessive work hardening during compression. When the nose radius of punch is increased from 0.1mm to 0.5mm, the deformation of sheet material between upper and lower punches becomes compression rather than cutting because of the suppression of the crack initiation and propagation from the punch nose portion. Therefore, when the punch of γ=0.5mm is used, the separated surface has a very thin flash. These experimental results are qualitatively in good agreement with the simulation results.
  • 吉村 允孝, 藤見 善久, 泉井 一浩
    2002 年 68 巻 668 号 p. 1310-1318
    発行日: 2002/04/25
    公開日: 2008/02/26
    ジャーナル フリー
    As the scope of elements considered by product designers has widened, the number of design criteria and variables has mushroomed. Companies now face a two-fold difficulty: design projects that can only be dealt with as large-scale optimization problems, and the need to shorten the development cycle time to the absolute minimum. This paper proposes a concurrent criteria-ordering method for large-scale design problems that not only gives the optimum order of criteria for evaluation, but also shows how criteria groups can be optimized in parallel. This method consists of two main techniques, based on criteria interrelationships: the selection of criteria blocks (i.e., collaborative blocks, parallel blocks) and the ordering of criteria. To demonstrate the effectiveness of the method, it is applied to the design of a bicycle.
  • 林 栽国, 林 准黙, 吉本 一穂, 金 甲煥, 高橋 輝男
    2002 年 68 巻 668 号 p. 1319-1328
    発行日: 2002/04/25
    公開日: 2008/02/26
    ジャーナル フリー
    In this paper, a guide path design method is suggested for automated guided vehicle systems using Q-learning technique. Numerous manufacturing companies have recognized various advantages of Automated Guided Vehicle System (AGVS) for material handling. These advantages include the flexibility in transportation, the improved space utilization, and the lead-time reduction. With the rapid advance of the state of art technology for AGVS, the application of AGVS to automated manufacturing systems has been more popular than ever before. However, the design of the guide-path network has been considered as one of difficulties in the application of AGVS. By applying the Q-learning technique, it is possible to consider the traffic congestion at intersections or at pickup/delivery stations, and interference among vehicles on bi-directional path segments. It is discussed how the Q-learning technique can be applied to the guide path design problem. A numerical experiment was performed to evaluate the performance of the rules obtained from the learning process for the network design. The result of this research is compared with those by previous studies.
  • 藤田 喜久雄, 吉田 寛子
    2002 年 68 巻 668 号 p. 1329-1337
    発行日: 2002/04/25
    公開日: 2008/02/26
    ジャーナル フリー
    This research discusses and develops the optimization methodologies for product variety design, which means the challenge to simultaneously design multiple products. Following the succeeding reports, this paper proposes a simultaneous optimization method for both module combination and module attributes of multiple products, which is viewed as the third class of product variety optimization in the first report. While it is the most difficult one among the classes, it includes a hierarchical structure on the design optimality, which is composed of commonality and similarity pattern, similarity directions, module attributes, under a systematic understanding of product variety representation. Based on such structure, this paper configures an optimization method for both module combination and module attributes across multiple products. The optimization method hybridizes a genetic algorithm, a mixed-integer programming method with a branch-and-bound technique, and a constrained nonlinear programming method, i.e., a successive quadratic programming method. In its optimization process, the first optimizes the combinatorial pattern, the second optimizes the well-structured directions, and the third optimizes the continuous module attributes under the others. Finally it is applied to the simultaneous design problem of multiple airplanes to demonstrate its validity and effectiveness.
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