-
Article type: Cover
Pages
Cover1-
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
-
Article type: Appendix
Pages
App1-
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
-
Article type: Appendix
Pages
App2-
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
-
Article type: Appendix
Pages
App3-
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
-
Article type: Index
Pages
A1-A6
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
-
Yoshiro TAKAMATSU, Michel MENSLER, Yoshitaka DEGUCHI, Haruki YASHIRO
Article type: Article
Session ID: 0124
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
The reduction of the noise due to the road irregularities in a car cabin, is a subject of research for many years. To reduce such a noise at all the seat positions, H2-based feedforward Active Structural Acoustic Control (ASAC) using a virtual sound sensing method has been proposed. By including the idea of the model order reduction for the implementation, we verify the usefullness of the proposed method by a car experiment.
View full abstract
-
Kunihiko ISHIHARA, [in Japanese], [in Japanese]
Article type: Article
Session ID: 0125
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
As tube banks are set in a duct in a boiler and a heat exchanger, the resonance phenomenon or the self sustained tone are generated due to the interference between a vortex shedding and an acoustic characteristic of duct. It is necessary to know the resonance frequency of the duct, namely sound speed, for avoiding any trouble that may arises. In general, it is said that the sound speed decreases in the duct with tube banks and an evaluation formula is given. However this formula is obtained to apply to the perpendicular direction to the flow. We want to know that this formula is able to apply to the flow direction and to various array patterns or not. Then in this paper, applicability limit of this expression is discussed by using FEM analysis and experiments.
View full abstract
-
Naoto KAWABATA
Article type: Article
Session ID: 0126
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
For a luxury sedan, quietness is a major selling point, and a luxury hybrid sedan is expected to be especially quiet. Therefore, in the development of the luxury hybrid sedan, every possible effort is needed to reduce the hybrid system noise in order to ensure a level of quietness far superior to that of an ordinary gasoline-powered vehicle. In addition, the noise and vibration phenomena that are particular to vehicles with longitudinal power trains require special reduction technologies. This paper describes the superior quietness of luxury hybrid sedans in comparison with ordinary gasoline-powered sedans and the development issues of vibration during engine starting, and motor noise, explaining the technologies employed to reduce them.
View full abstract
-
Satoshi Isetani, Akira Sadamoto
Article type: Article
Session ID: 0127
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
A splitter that is a thin plate inserted in a rectangular duct can be used as a simple device for attenuating the sound propagating in the duct. In the frequency range where only the plane wave can propagate, this effect is obtained in the case that the splitter is inserted in a duct bend. On the other hand, the splitter in a straight duct works when the (1,0) mode sound wave propagates. In this research, the effect of the splitter inserted in a duct bend is examined experimentally in the frequency range where the (1,0) mode wave can propagate. In this range both the plane and the (1,0) mode waves are transmitted while the single mode wave, either of the plane or the (1,0), enters the bend. Using the measured data of sound pressure, the sound power of each wave is calculated, and then the transmissivity of the splitter is evaluated. The effect of the splitter depends on the splitter length and its insertion position. In addition, the effect differs depending on the mode of incident sound wave.
View full abstract
-
Toru YAMAZAKI
Article type: Article
Session ID: 0128
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
This paper derives the modal descriptions of structural intensity for flexural vibration on plates. The modal expansion of the intensity is superposistioned by modal terms expressed by the product of weight function and the product of two modes with or without spatial derivative, which is called "cross-modal function" in this paper. It is also demonstrated that the expansion can design the excitation position for realizing the vortex energy flow on the plate, which flow type affects the radiation efficiency strongly. It is also shown that the products of two natural modes have the relation with the cross-mode functions, which enables to predict roughly the cross-mode functions when it is difficult to evaluate the spatial derivatives of natural mode.
View full abstract
-
Masaharu Okamura, Toshifumi Sakai, Noritoshi Nakagawa
Article type: Article
Session ID: 0129
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
This paper describes the thermoplastics reactive type sound absorber. We can form one structure absorber with holes by injection expanded molding. The injected long glass fiber reinforced polypropylene can expand twice or more caused by spring back effect. The thickness of surface layer, which does not expand, and the inner porous core are about 0.5 and about 8mm, respectively. By opening holes in one side of surface layer, resonance type sound absorber is made. By changing radius or interval of holes, absorption frequency can be controlled freely.
View full abstract
-
Etsuro YOSHINO, Toru WATANABE, Kazuto SETO
Article type: Article
Session ID: 0201
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
One of the authors had already proposed effectiveness of connected control method (CCM) for vibration control of flexible structures arranged in parallel. This paper deals with hybrid vibration control using CCM applied to two flexible parallel buildings with different heights and stiffness. In order to adjust maximum amplitude of the first mode of each structure, an active controller is used, while a passive damper is applied for suppressing structural vibration with lower energy consumption. In this paper, a basic research is also presented for applying CCM to single building constructions.
View full abstract
-
Yuji ISEKI, Hiroshi MATSUHISA, Hideo UTSUNO, Katsutoshi SAWADA
Article type: Article
Session ID: 0202
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Rollover and downfall are uncomfortable for people on a boat and it is necessary to suppress the rolling occurred by ocean waves while a boat is moored. In this study, a new method that cylinders with orifices at bottom side are placed on the both sides of a boat is proposed. When the water passes through the orifice, the difference of the pressure is produced on the both sides of the orifice. This difference of the pressure works as the force for vibration suppression. Optimal values of this equipment were derived theoretically. And the effectiveness of proposed method was verified by the calculation and experiment.
View full abstract
-
Hiroki MATSUMURA, Hiroshi MATSUHISA, Hideo UTSUNO, Katsutoshi SAWADA
Article type: Article
Session ID: 0203
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
This paper describes an active control method by Coriolis force for swing reduction of a crane load. Coriolis force is generated when a mass on a wire of a crane moves up and down in the radial direction. The effect of vibration suppression is examined by numerical analysis and experiments. In this research, a wire of a crane is regarded as a rigid rod which is the simplest model. The effect of vibration suppression is linearly proportional to the angular amplitude of a crane. It is confirmed that the swing can be suppressed by the active Coriolis damper.
View full abstract
-
Hiroaki HANAI, Shigeo KOTAKE
Article type: Article
Session ID: 0204
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
-
Nobutaka TSUJIUCHI, Takayuki KOIZUMI, Shin NAKAHARA, Ichiro KIDO, Masa ...
Article type: Article
Session ID: 0205
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
In the automobile development, it is important to understand the vibration transfer characteristic of automotive body structure to establish countermeasures efficiently. However it is difficult because of many substructures are assembled complexly. In this paper, an analytical technique is proposed to raise the efficiency of the vibration transfer analysis. The vibration transfer is examined based on the contribution to response of transmitted forces on cross-section of automobile framework. The analytical degree of freedom (DOF) is transformed to the modal coordinates, and the transmitted forces are expressed on new coordinates. By using the new transmitted force, the contribution to response of cross-section deformation is calculated. The proposed method enables the analyst to understand the vibration characteristic and draw countermeasures effectively.
View full abstract
-
Nobutaka TSUJIUCHI, Takayuki KOIZUMI, Takudou OHKADO, Hiroaki ANDOU
Article type: Article
Session ID: 0206
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
A mount, which combines air-spring with viscous fluid is designed. In this mount, air-spring generates the dynamic stiffness, and shearing of viscous fluid generates the loss stiffness. The conceptual purposes are to adjust a neutral position easily by changing the pressure of the air-spring and to prevent a rapid drop of the damping performance from the stationary characteristics in case of excess load. The purpose of this research is to evaluate damping properties of the composite mount. First, the dynamic characteristics of the composite mount are obtained by excitation tests of the mount itself. But the characteristics might not be identified by the standard mechanical model accuracy because they depend on not only excitation frequency but also amplitude. So the nonlinear dynamic characteristics are identified using five-element Maxwell model with a variable parameter. Finally, the composite mount is compared with the viscous mount by the simulation using the identified model, and the damping performance quantitatively indicated.
View full abstract
-
Kazuhito KATO, Toru Kanke, Takuya Yoshimura, Gen Tmaoki, Satoshi Kitaz ...
Article type: Article
Session ID: 0207
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
A seat-human combined model using multibody dynamics (MBD) was developed to predict passenger's motion due to vehicle lateral motion for use of ride comfort evaluation. Human body was divided into thirteen rigid parts and they were connected by rotary joints with springs and dampers. A vehicle seat was also modeled using MBD. Parameter values were identified by using experimental vibration transmissibility data of human body and seat. Finally, these two models were combined, and passenger's motion was calculated. The result of comparisons of measured data and calculated data showed that the developed multibody models could predict passenger's head lateral and roll motion on a vehicle seat.
View full abstract
-
Yoshihiko KAWAZOE, Shintaro MORIYAMA, Jun TAGUCHI
Article type: Article
Session ID: 0208
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
There is no robot around us in our society at the current stage and also there will be no robot in the future if we define a robot as an machine working in the arena of offices, homes, and disaster sites, etc. outside the factories and also continue the present conventional research and development (R & D) style in robot projects. We proposed the concept of Human-Robotics, where robots and engineers should learn and develop in collaboration with each other in the real world on the basis of the dexterity of nature, life and human with Subsumption Architecture (SA) in the previous paper. We showed as the case studies the simple self-sustained humanlike robust walking & running & instantaneous turn NANBA of humanoid biped robot GENBE based on distributed control of physical body in a martial art utilizing instability without ZMP (Zero Moment Point) control, which uses only small active power with simple chaotic limit cycle utilizing instability, further developing into autonomous shock avoidance during falling down owing to being pushed from backside and instantaneous rising. Instability makes the natural movement. We also showed the case study of an autonomous robot without SMPA (Sense-Model-Plan-Act) framework. In this paper, we realized the JIZAI movement of humanoid biped robot based on the distributed control of physical body in a martial art going up and down the stairs with instability.
View full abstract
-
Yoshihiko KAWAZOE, Jun TAGUCHI, Junichi KEBUKAWA
Article type: Article
Session ID: 0209
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
It seems that the emergence of intellectuality in an autonomous robot exists in the dexterity of human or creatures as complex systems. The previous paper proposed the research style and the development procedure along this approach for realization of a real intellectual robot. We call this Human-Robotics, where robots and engineers should learn and develop in collaboration with each other in the real world on the basis of the dexterity of nature, life and human. We realized the simple self-sustained humanlike robust walking & running NANBA of humanoid biped robot GENBE based on distributed control of physical body in a martial art utilizing instability without ZMP (Zero Moment Point) control, which uses only small active power with simple chaotic limit cycle utilizing instability, further developing into autonomous walking & running. Instability makes the natural movement. We also investigated the approach to the emergence of the intellectuality of an autonomous robot for breaking through the problems of the conventional intelligent robot with SMPA (Sense-Model-Plan-Act) framework in the real world. It is based on the development of human's dexterity or proficient skills with Subsumption Architecture (SA) by learning in the real world. This paper showed the development of NANBA Run of Humanoid Biped Robot GENBE with small-sole in order to make full use of instability as a source of driving force based on the distributed control of physical body in a martial art.
View full abstract
-
Motomu NAKASHIMA, Keiko YONEYAMA, Tasuku MIYOSHI
Article type: Article
Session ID: 0210
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
The objective of this study was to propose the optimal gait for muscle training during walking in water. First, the simulation method, which has been developed by the authors, was briefly described. The method consists of the inverse dynamics analysis part, which is a variation of the authors' swimming human simulation model SWUM, and the two-dimensional musculo-skeletal analysis part. Second, the evaluation index for the muscle training and the penalty index for the load on the joint were defined. Third, various gaits were analyzed by the simulation method. From the analysis, two gaits accompanying the large joint motions at the hip and knee were selected as the optimal gaits, by comparing the evaluation and penalty indices.
View full abstract
-
Tasuku MIYOSHI, Keiko YONEYAMA, Motomu NAKASHIMA, Kimitaka NAKAZAWA, M ...
Article type: Article
Session ID: 0211
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
The aim of this paper was to validate the optimal gait form for hip flexion and/or extension muscle group strengthening while walking in water. Five healthy young males participated in our experiments, and performed three gait forms; one is the normal form and the others were selected from the previous simulation study. These newly gait forms while walking in water were hip maximum voluntary flexion/extension with or without knee flexion for forward/backward direction, respectively. When subjects walked forward/backward direction with newly gait forms, the rectus/biceps femoris muscle electromyographic activities were enhanced compared with that of normal form. These results suggested that the optimal form based on the simulation study had high validity, and the hip flexion or extension muscle group could be strengthened selectively while forward or backward walking in water.
View full abstract
-
Hiroshi TOKUNAGA, Shoji KAMIZATO
Article type: Article
Session ID: 0212
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
The leg joint mechanism in human hopping was modeled, and the numerical simulation was carried out. The movement of each joint during jumping is studied by deriving the equation of the motion based on the Lagrange method, giving the initial value based on an actual human body, and adjusting the numerical values. The feature of the movement of each joint in the jump's moving was able to be captured by solving equations by using the fourth Runge-Kutta methods for the temporal integration. Since the rigidity and the damping coefficient in each joint are adjusted until it succeeds to land, before falling. Therefore, the problem in simulating the jump movement of the human human hopping was partially clarified.
View full abstract
-
Kazutaka GOTO, Hiroshi MATSUHISA, Hideo UTSUNO
Article type: Article
Session ID: 0213
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
A human's gait rhythm changes into the frequency of the ground vibration from one's natural gait rhythm. This phenomenon is called as "pull-in effect". It is known as a cause that London Millennium Bridge closed soon after it had opened. The pull-in effect has been investigated by means of the neural oscillator and active motion to avoid falling. But the purpose of these studies was explanation of pull-in effect qualitatively and few studies have focused on the quantitative analysis. In this research, dynamics model was improved. New model can be expected to have good frequency range of pull-in effect and give good horizontal excitation power. Simulation result of phase difference between bridge and human corresponds to experimental result. In order, to evaluate pull-in effect of a real pedestrian bridge, simulation of walking on the free platform was carried out. In conclusion, a quantitative analysis of the pull-in effect became possible with the use of improved passive walking model.
View full abstract
-
Yuutaku KANETA, Hisashi OOKAWA, Takatoshi UMENO, Toshiaki HARA
Article type: Article
Session ID: 0214
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
In this paper, dynamic strain characteristics under impact load application to lower extremety is investigated to study a pedestrian knee jnjured by traffic accident and load transmission mechanism from cortical to trabecular bone. The hog lower extremity is used and subjected to side impact load. The experimental results show that siginificant difference in load transmission characteristics between lateral and medeial is observed, and that the similar tendency to that by Murase is presented.
View full abstract
-
Yosuke EGUCHI, Haruo SHIMOSAKA, Noburo EHARA
Article type: Article
Session ID: 0215
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
This paper describes a method to estimate weight by using fluctuation of ground reaction force in bending and stretching exercise. We calculate the vertical acceleration of the body's center of gravity regarded as a quadratic function from the force, and estimate weight by taking the average of calculated weight from two terms when the body is lowered in exercise. Compared to the actual weight, the error in the average presumption value of weight is less than 1.3%.
View full abstract
-
Kenji SHIGETOSHI, Ryuta OZAWA, Tetsuya MORIZONO, Tadao ISAKA, Sadao KA ...
Article type: Article
Session ID: 0216
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
The aim of this study was to develop the training method for the selective muscle strengthening using the mechanical impedance load. One male subject completed fully elbow flexion in two loading manners which were the isoviscous load (3.0,5.0,8.0,12.0,20.0,30.0[Nm/s/rad]) and the mechanical impedance load. The mechanical impedance load of this study was the load changing from isoviscous load to elastic load during the motion. The comparison of these results implied the possibility of the selective muscle strengthening using our proposed training method.
View full abstract
-
Koichi SAGAWA, Kazuhiro FUJISAWA, Mizuri ISHIDA
Article type: Article
Session ID: 0217
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Estimation of stability of standing during recovery phase after frontal inclination using video-captured posture is discussed. Two-link inverse pendulum models is applied to the human body to estimate viscoelastic coefficients, i.e. natural frequency and dumping ratio, of ankle and waist during the recovery phase only. One subject is asked to stand still, incline forward as far as possible and return to the original posture in subject's eyes-opened, eyes-closed and one-legged condition. The estimated viscoelastic coefficient of ankle and physical parameters such as body weight, length and moment of rotational inertia are applied to one-link inverse pendulum to derive natural frequency and dumping ratio of second order transfer function which simplifies the dynamics of standing human. The experimental results show that the dumping ratio maximizes during eyes-opened condition and minimizes during one-leg condition. It is suggested that the damping ratio indicates the ability of dynamical postural control.
View full abstract
-
Takayuki USUDA, Shinichi OTO, Junichiro MISHIMA
Article type: Article
Session ID: 0218
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Authors proposed a technique to improve the compliance characteristics of pantograph such as shifting the natural frequency of a pantograph-head and a technique for selecting suitable spring constant by using Genetic Algorithm. This is based on the dynamic model of pantograph in which the degree of freedom is increased and the effects caused by contact wire deviation, a pantograph-head interval and the pitching mode of a pan-head support can be examined. In this paper, the validity of this method has been performed through line test.
View full abstract
-
Naoki MIYAJIMA, Makoto KOMIYAMA, Yohei MICHITSUJI, Yoshihiro SUDA, Aki ...
Article type: Article
Session ID: 0219
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Railway truck is necessary to have excellent curving performance as well as high speed hunting stability, but generally they are contrary to each other. "Active-bogie-steering (ABS) Bogie", is one of the methods to realize the compatibility between curving performance and hunting stability. ABS bogie has active steering mechanism only between car body and bogie frame, and bogie frame is steered by actuators toward "radial steering position", which realizes no "bogie angle shortage". In this paper, more detailed study and evaluation for ABS bogie will be presented. Bogie control strategies which minimize a certain cost function including contact lateral forces for leading-outside wheels of each bogie is proposed. According to the numerical simulation with multibody dynamics software, the effects of wheel tread profiles are proved. Moreover, calculations of hunting stability for ABS truck with three tread profiles.
View full abstract
-
Masahiro MIWA, Yosuke SAKAI, Takeshi TSUCHIYA, Shinji SUZUKI
Article type: Article
Session ID: 0220
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Real-time flight trajectory optimization algorithms and Non-linear Dynamic Inversion (NDI) controller are developed and evaluated through numerical simulations. The purpose of this study is to guide and control an aircraft in emergency landing by using 4D navigation algorithms. This paper considers the real-time direct trajectory optimization method that can deal with constraints strictly. NDI controller is proposed as reconfigurable control system to deal with the changes in dynamic characteristics during the flight. For the purpose of realization of this system, the real-time direct trajectory optimization and the NDI flight control law was designed for flight testing of the experimental aircraft MuPAL-α owned by JAXA and evaluated through numerical simulation.
View full abstract
-
Ryosuke TANOUE, Sho UMEZAWA, Yoshitaka SHIMANO, Osamu KOBAYASHI
Article type: Article
Session ID: 0221
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Flight test data is useful and helpful to study the dynamic aerodynamic characteristics of an airplane. This report shows the trial of construction of a flight test system to fly a model airplane in a wind tunnel for the purpose of getting its flight time history data. As the wind tunnel is comparatively small, it is very difficult that two ground human pilots make fly a model airplane far a certain long time without their excellent piloting technique and help of a adequate stability and control augmentation system (SCAS).
View full abstract
-
Satoshi TOMITA, Hidehisa YOSHIDA, Masao NAGAI
Article type: Article
Session ID: 0222
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
This paper describes extraction method of driver behavior by using pressure distribution of the seat. Recently, a system which can monitor a car driver's biological condition and behavior is being proposed. In addition, new driver assist systems which are based on driver's biological condition and behavior are studying. Now, pressure of the driver's sheet has been noticed as one of the methods of measuring driver's biological conditions. The relation between step change of the pedal operation and the pressure distribution of the seat is investigated. The result of this study revealed that the driver's pedal stepping substitution behavior has been extracted from the seat contact pressure.
View full abstract
-
Chihiro NAKAGAWA, Shoichiro TAKEHARA, Yoshihiro SUDA, Kimihiko NAKANO, ...
Article type: Article
Session ID: 0223
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
In this paper, the dynamic characteristics of a small wheel bicycle are discussed. In the dynamic analysis with multibody dynamics, the influence of the head angle on the small wheel bicycle is investigated. With the driving experiment of the small wheel bicycle, straight-ahead stability and upstanding stability are evaluated by the subjects and measured by the experimental apparatuses. The results show the smaller head angle has more stability and the results are corresponding with the simulation results.
View full abstract
-
Hiroshi TOKUNAGA, Akinori TAKEDA
Article type: Article
Session ID: 0224
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
We treat the motion of the motorcycle which incorporated telelever suspension mechanism in the front as a simulation model and study a numerical simulation on an uneven road surface. We make a two-dimensional model of a motorcycle comprising three barycentric coordinate systems of body, front and rear wheel, set a coordinate of a connecting point of a mechannical element, and derive Lagrange equation by three barycentric coordinate systems. We demand basic equations with Lagrange's method of undetermined multipliers. We give specifications based on a real motorcycle and formulated it about behavior of suspension for a change of a road surface and perform numerical analysis. It uses numerical calculation method with the fourth-order Runge Kutta method to integral calculus in time of a ordinary differential equation. In addition, I made a three-dimensional model of a motorcycle, as well as a two-dimensional model, and derive the Lagrange equation by three barycentric coordinate systems.
View full abstract
-
Shoichiro TAKEHARA, Yoshihiro SUDA
Article type: Article
Session ID: 0225
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
This study is focused on dynamic behavior of a small size tire. A small size tire is used for personal mobility, for example, a bicycle, a wheelchair and so on. We made experiments device for vertical behavior on bump for small size tire. We performed experiments to investigate the vertical behavior on bump for small size tire. We measured the force, the acceleration acting on tire and the vertical displacement of tire.
View full abstract
-
Wataru MURATA, Hiroki WATANABE, Yukinari TANAKA, Taichi SHIIBA
Article type: Article
Session ID: 0226
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Effects of suspension geometry on vehicle dynamic characteristics were investigated with an actual vehicle. For this purpose, we developed an electric vehicle with variable geometry suspension, and evaluated three geometry patterns by performing steady state circular tests. Furthermore, the vehicle dynamic characteristics were examined with multibody dynamic analysis under the same conditions. By comparing these results, the effect of suspension geometry on vehicle dynamic characteristics are discussed in this paper.
View full abstract
-
Yuichi UENO, Taichi SHIIBA
Article type: Article
Session ID: 0227
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
This paper deals with a driving stability analysis method of a kart considering an elastic deformation of the kart frame. The stiffness matrix of the kart frame was calculated with the finite element method, and the vertical load of each tire simulation was analyzed with this stiffness matrix. In addition, the vertical load distribution was examined with tests to validate the stiffness matrix, and it was confirmed that the experimental results agree with simulation results. Furthermore, the driving stability was evaluated with simulations, and it was observed that the elastic deformation of the kart frame effects on the steering characteristic.
View full abstract
-
Akihiro KIMURA, Masaharu NISHIMURA, Tomonobu GOTO
Article type: Article
Session ID: 1501
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Modeling method of pile fabrics was studied in the CFD simulation. The porous media model in Fluent 6.3 was used and VRC (the viscous resistance coefficient) proportional to the inverse third power of the distance from the cylinder surface was found to be appropriate to model the pile fabrics. The simulation results show the similar flow pattern around the cylinder with/without pile fabrics, as measured in the previous experiments. However, the simulated turbulent intensities have not yet had good agreement with the experimental results.
View full abstract
-
Yuichiro KURODA, Takahiro KAMIKUBO, Tomonobu GOTO, Masaharu NISHIMURA
Article type: Article
Session ID: 1502
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Overlaying an object in a flow with a multi-layered mesh as well as a pile-fabric is expected to be feasible as to reduce aerodynamic noise from the object. The mesh or the fabric weakens the accelerating vortices that are the sources of the sound. Because the vortices produce the pressure distribution around the cylinder, the aerodynamic forces will be also changed by the mesh or the fabric. In this study, aerodynamic forces exerted on circular cylinders whose surfaces were overlaid with multi-layered meshes were measured in a low-noise wind tunnel, and were compared with the forces of cylinders without the meshes. Unsteady forces in the directions parallel and perpendicular to the flow were reduced by the mesh. The drag of the cylinder was proportional to the diameter of the cylinder including the thickness of the mesh.
View full abstract
-
Takeshi SUEKI, Takehisa TAKAISHI, Mitsuru IKEDA
Article type: Article
Session ID: 1503
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
The noise reduction along a railway line is very important for further speed-up of a high-speed train. Especially, the aerodynamic noise caused by a pantograph is the main noise source, accordingly it has become increasingly important to reduce it. In this report, the method of the aerodynamic noise reduction has been proposed, which covers an object surface with a porous material. The effect of aerodynamic noise reduction has been confirmed by a wind tunnel test with a cylinder, accordingly this method has been applied to a pantograph, and it has been revealed that the aerodynamic reduction effect has been obtained.
View full abstract
-
Sadao AKISHITA
Article type: Article
Session ID: 1504
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Introduction of perforations in the walls of flow surface causes not only significant sound attenuation but also reduction of aerodynamic sound radiation from a rotating wing. In order to enjoy the largest advantage of perforated surface, the optimal distribution of finite impedance should be realized, which means the impedance characteristics of the surface must be predicted under the grazing flow condition. In this paper grazing flow effect on the surface impedance was investigated by conducting a numerical simulation, where the diameter is 1mm and the Reynolds number based on the diameter ranges from 44 to 230. The complex surface impedance ratio marks far larger magnitude than the conventional impedance for larger diameters and higher Reynolds number, which reflects the effect of high viscosity of the flow.
View full abstract
-
Ryo SUZUKI, Toshio IIJIMA, Minoru MAEDA, Takuya KOMORI, Shuntarou MURA ...
Article type: Article
Session ID: 1505
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
This paper presents equations for predicting transmission loss characteristics of a silencer with multiple resonators. An example of result shows that this device is to be expected to control random-frequency noise traveling in duct systems.
View full abstract
-
Hideo KURASAWA, Yoshiaki HANEDA
Article type: Article
Session ID: 1506
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Self-sustained oscillation of a shear layer occurs in the jet-pipe system when a pipe is placed coaxially with around jet axis. The velocity fluctuation in this phenomenon is accompanied by a pure tone radiating from the leading edge of the pipe. Though the level of this tone is generally very small, a high sound level is produced by produced by the coupling of the acoustic resonance of the pipe to the periodic oscillation of the flow in the jet. In this paper several methods are proposed in order to attenuate the acoustic resonance produced by this coupling, and the effect of attenuation is investigated experimentally.
View full abstract
-
Hiromitsu HAMAKAWA, Tomohiro KUDO, Eiichi NISHIDA, Tohru FUKANO
Article type: Article
Session ID: 1507
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
The effect of fin around a bare tube on Karman vortex shedding was experimentally investigated. This fin was made from a thin plate and mounted spirally around a bare tube surface. We measured the distributions of the mean velocity, the intensity of velocity fluctuation, the spectrum of velocity fluctuation and the coherence distribution of Karman vortex along the tube axis. And the flow around the fin tube was visualized by using the smoke wire technique. As a result it was made clear that the periodic velocity fluctuation caused by Karman vortex was observed in the wake of the fin tube although the fin mounted around a bare tube. The vortices in the near-wake of the fin tube make the cell structure with the scale of the pitch length of the fins. The rotation axis of the each vortex was inclined against the tube axis. The large scale vortex was formed by the reconnection of the vortex cells.
View full abstract
-
Chikara YAMAGUCHI, Kenji MORITA, Toshitaka MINBU, Akiyoshi IIDA
Article type: Article
Session ID: 1508
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
In order to clarify the effect of incoming flow turbulence, aerodynamic noise and static pressure fields were measured in a low-noise wind tunnel with an active turbulence generator. The experimental results showed that influence of turbulence intensity for aerodynamic noise generation was not clear. However, the noise levels depended on the eddy scale of the uniform flow. The distributions of the static pressure in the wake of the circular cylinder were also measured with and without the active turbulence generator. Since the eddies which is almost the same size have an inclination to interfere in each other, Karman vortex disappeared when the case of the scale of eddies were almost the same as the diameter of the cylinder. Therefore, the resultant noise decreased.
View full abstract
-
Eri FUKUYAMA, Akiyoshi IIDA, Mizuki NAKAMURA, Chisachi Kato
Article type: Article
Session ID: 1509
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
In order to clarify the generation mechanism of aerodynamic sound from a cavity, aerodynamic sound and flow fields around a cavity were measured with a high speed flow visualization system. In this experiment, deep cavities were used; however, acoustic resonance was removed with acoustic insulator. The flow visualization results showed that the two large scale vortices were observed in the cavity. When the first vortex attached the downstream edge of the cavity, sound level was low. The sound level was increasing with the vortex impinging the edge of the cavity. When the center of the vortex core reached the edge of the cavity, the sound level reached maximum level. And sound level gradually reduced because vortex core through the edge. The dynamic PIV can be captured vortex deformation. We also visualized vortex structures around a round edge cavity. In the case of the round edge cavity, vortex deformation was alleviated. As a result, the resultant sound was reduced. These results indicated that the deformation of eddies play an important role with the aerodynamic sound generation.
View full abstract
-
Kotaro SATO, Riho HIRAMOTO, Kuniaki TOYODA
Article type: Article
Session ID: 1510
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Mechanisms of aerodynamic sound generation from a separated turbulent shear flow were studied experimentally with measurements of aerodynamic sound and fluctuating static pressure. Sound source term in the equation of Ribner's dilatation theory was obtained with second time derivative of fluctuating static pressure measured in the separated turbulent shear flow from an edged fence. The authors discussed on spectra and coherence of the aerodynamic sound and the sound source term to identify locations of the sound source and vortex motion contributing to the aerodynamic sound generation. The results suggest that the sound source exists on an early stage of the separated shear flow where vortex rolling-ups occur, and the measurements of fluctuating static-pressure give us useful information on relationship between a sound source caused by vortex motion and aerodynamic sound.
View full abstract
-
Takuya KOMORI, Shuntaro MURAKAMI, Toshio IIJIMA
Article type: Article
Session ID: 1511
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
This paper presents experimental investigations on relationships between jet-generated tone and fluctuating velocity in an axisymmetric deep cavity. It is shown that Strouhal frequencies obtained from predominant components in spectra of both quantites agree fairly well respectively and each of them increases as cavity length/diameter ratio is increased up to roughly 0.6. It is also shown that the correlation of both components becomes strongest close to the cavity exit. These facts suggest medium-particle excitations with the predominant frequency of resonance tone caused by vortices impinging on the cavity-end edge.
View full abstract
-
Taku HONDA, Akiyoshi IIDA, Hiroshi YOKOYAMA, Chisachi Kato
Article type: Article
Session ID: 1512
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
The aim of this investigation is to develop the aerodynamic noise reduction technique for automobiles with active control. To reduce the tonal noise from a rear-view mirror, oscillating jets were impinging into the boundary layer of the rear-view mirror. Since the aerodynamic tonal noise of rearview mirror was generated by a small perturbation caused by a small step on a surface of the rearview mirror, oscillating jets were destroyed the seed of the noise. The experimental results showed that the noise reduction level depended on the frequency and intensity of the oscillating jets. The tonal noise level of the rear-view-mirror with the active control was 20dB smaller than that of the conventional rear-view mirror. The average velocity of the impinging jet was only 0.3% of that of the uniform flow. It revealed that the oscillating jets effectively reduced aerodynamic noise with small amount of energy.
View full abstract
