著者

雉本 信哉 下嶋 浩

出版者

一般社団法人日本機械学会

雑誌

日本機械学会論文集. C編 (ISSN:03875024)

巻号頁・発行日

vol.61, no.589, pp.3581-3586, 1995-09-25

参考文献数

9

被引用文献数

4

---

A new adaptive control algorithm in frequency domain was proposed. This frequency domain approach corresponds to the ordinary filtered-x least mean square (LMS) algorithm in discrete time domain. In this approach, the fast Fourier transform (FFT) was used for converting signals between frequency domain and discrete time domain. Since the computaion processes in these two domains are almost independent with each other, this algorithm can be realized effectively by using two processors. Computer simulations were carried out for investigating convergence characteristics of this approach. As the result of these simulations, it was shown that this algorithm has faster convergence with less computation comparing to the ordinary filtered-x LMS algorithm.

著者

西原 修 松久 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. C編 (ISSN:03875024)

巻号頁・発行日

vol.63, no.614, pp.3438-3445, 1997-10

参考文献数

6

被引用文献数

9

---

Fixed points design methods for dynamic vibration absorbers are very well-known in the field of vibration control and commonly applied for practical absorber design. However, they must be understood to be approximation methods from the point of view of their design criterion that the resonance amplitude magnification factor is minimized. In this study, the exact algebraic expressions of optimum tuning and damping parameters for the minimization of the largest resonance amplitude magnification factor of linear dynamic vibration absorbers have been derived for undamped primary systems. The existence of two equal height resonance points is reduced to a multiple root condition of an algebraic equation. The determinant is handled as an equation with respect to the resonance amplitude. It has became very clear that the fixed points theory design by Brock is highly accurate. In particular, it exhibits very small error in the practical mass ratio range, e.g., below unity. Algebraic solutions also exist for the resonance frequencies and the anti-resonance frequency. A numerical extension of the method is introduced in order to investigate the optimization problem for damped primary systems.

著者

浅見 敏彦 細川 〓延

出版者

一般社団法人日本機械学会

雑誌

日本機械学会論文集. C編 (ISSN:03875024)

巻号頁・発行日

vol.61, no.583, pp.915-921, 1995-03-25

参考文献数

15

被引用文献数

5

---

This paper proposes an expression for design of optimal dynamic absorbers attached to damped linear systems. The classical expressions were derived from the assumption that the primary system has no damping. There are two optimization criteria in the design of the dynamic absorber : the fixed-points theory and the minimum variance criterion. In the fixed-points theory, the dynamic absorber is optimally tuned and damped with respect to the primary system so that the two resonant amplitudes of the main mass are equal. On the other hand, in the latter criterion the area under the power spectrum density curve of the main mass is adjusted to take the minimum value. The new expression proposed in this paper is based on the fixed-points theory. However, there are no fixed points in the resonance curves of the damped linear systems, so the analytic procedure becomes impossible. Therefore a perturbation method is used to obtain the expression, and the accuracy of the solution is discussed.

著者

橋場 邦夫 寺尾 憲 久納 孝彦

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.64, no.620, pp.1339-1346, 1998-04

被引用文献数

9

---

The theory of squeeze film pressure and the theory of acoustic radiation pressure have been generalized to a new theory in this study. When the two fiat faces are separated by a compressible fluid film, a dynamic pressure is generated in their normal direction by the oscillation of the faces. One of the authors derived a fundamental equation for the phenomenon considering both the inertia and the viscosity of the fluid. In case of neglecting the inertia effects and assuming the isothermal change, the equation is reduced to the Reynolds equation used in the conventional lubrication theory. In this paper, an analytical solution of the Reynolds equation on the adiabatic squeeze film is presented. The results show that compressibility effects of the fluid are dominant at high squeeze numbers. The relationship between the squeeze film pressure and Rayleigh radiation pressure is also investigated theoretically.

著者

佐藤 凖一

出版者

一般社団法人日本機械学会

雑誌

日本機械学会論文集. C編 (ISSN:03875024)

巻号頁・発行日

vol.64, no.627, pp.4109-4114, 1998-11-25

参考文献数

32

著者

井坂 秀治 西田 公至 齋當 建一

出版者

日本機械学会

雑誌

日本機械学会論文集. C編 (ISSN:03875024)

巻号頁・発行日

vol.66, no.645, pp.1502-1508, 2000-05 (Released:2016-02-15)

被引用文献数

1

---

The purpose of the present investigation is to design an adaptive noise control muffler which has the most suitable location of secondary source. In the experiment, the distribution of sound pressure level in the muffler model has been measured by a sound visualization technique in order to obtain the maximum sound reduction by the minimum secondary sound under active control. The experimental results show that the target frequency could well be attenuated when the distance between the primary source and the secondary source is equal to the length eguivalent to one-half of the wave length of a target sound or its integral multiples.

著者

宮本 岳史 石田 弘明 松尾 雅樹

出版者

一般社団法人日本機械学会

雑誌

日本機械学会論文集. C編 (ISSN:03875024)

巻号頁・発行日

vol.64, no.626, pp.3928-3935, 1998-10-25

参考文献数

10

被引用文献数

4

---

We have developed the new simulation program which can deal with the large displacement, as the railway vehicle derails or overturns and wheels leave from rails. The dynamic behavior of railway vehicles running on track vibrated due to earthquake is analyzed, using this numerical simulation. The tentative running safety limits are proposed, that show the critical amplitude of track vibration at each frequency against the derailment. Moreover, the influence of vertical track vibration besides lateral one on the running safety limits is investigated. As a result, it is found that the vehicle running safety against earthquake has strong relation to the lateral track vibration, although the vertical vibration promotes the jumping of wheels. In the low frequency area, the rolling of carbody is excited gradually, and then the vehicle overturns, when it suffers the large amplitude seismic motion. In the high frequency area, the wheel flange comes into collision with rail at the first or second vibration, and the wheel jumps and leaves from rail. In respect of the critical track acceleration, railway vehicles have a tendency to be able to stand the earthquake with high frequency vibration more than 1.4 Hz.

著者

永瀬 和彦 近藤 和宏 野村 俊明

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. C編 (ISSN:03875024)

巻号頁・発行日

vol.63, no.606, pp.620-627, 1997-02-25

参考文献数

6

被引用文献数

3

---

Many trains were derailed and damaged by the earthquake in Kobe on January 17, 1995. At the same time, many railway girder bridges and viaducts were seriously damaged by the quake. It was postulated that serious accidents could occur as a result of trains running at high speeds into these girder bridges or viaducts. Fortunately, no fatal accidents occurred. On investigating such accidents, the authors found that they rarely occur, because a train derailed by the violent shock of a quake is so radically decelerated by the huge running resistance caused by the derailment that it stops just after the quake. On the other hand, it takes some time until the bridges or viaducts collapse after the quake.

著者

田中 真美 長南 征二 江 鐘偉 中島 英貴

出版者

日本機械学会

雑誌

日本機械学会論文集. C編 (ISSN:03875024)

巻号頁・発行日

vol.65, no.631, pp.970-976, 1999-03

被引用文献数

4

---

This paper is a study on the valuation and mathematical formulation of human touch sensation. First, the feelings of touch are collected on five natural and chemical fabrics through the SD (Semantic Differential) method questionnaires sent to twenty three examinees. The feelings are valued on each fabric by using the weigthed mean on graded factor feelings. The multiple regression analysis is then introduced to represent the overall evaluation of touch on every fabric by a linear function of the valuations on feelings of touch. Next, a soft tactile sensor made of a PVDF (Polyvinylidene Fluoride) film patch and rubber layers is assembled and slid over the same sample fabrics to collect the surface tactile information on the fabrics. The features on the collected data are then extracted by calculating the temporal average of absolute out signal and using the intensity of power spectral density on the medium frequency range. Comparison of the results show that the PVDF sensor well describes the tactile perception of forefingers.

著者

高橋 俊典 青木 勇

出版者

一般社団法人日本機械学会

雑誌

日本機械学会論文集. C編 (ISSN:03875024)

巻号頁・発行日

vol.62, no.600, pp.3196-3201, 1996-08-25

参考文献数

5

被引用文献数

2

---

This paper proposes a new system for analyzing the shearing process using the visioplasticity method. This visioplasticity method is well known as a method for analyzing the metal deformation processing. Drawbacks to the grid method such as large deformation cannot be treated, time-consuming, Processing procedure is complex when image processing by computer is performed, have been overcome with this newly developed method. This newly developed method consists of the following steps. First, images of materials at an arbitrary stage and the following stage are input into the computer. Next, the displacement between the two stages is obtained by a correlation methed based upon the inverse Fourier transform of the phase difference between two images. By repeating this process, the whole forming process can be analyzed accurately in a short time under a wide range of deformation. In order to verify this proposal, practical shearing tests and the analysis of these tests using this system were carried out. As a result, the distribution of displacement and strains until a very large plastic deformation of the material could successfully be obtained.

著者

杉本 浩一

出版者

一般社団法人日本機械学会

雑誌

日本機械学会論文集. C編 (ISSN:03875024)

巻号頁・発行日

vol.66, no.646, pp.1927-1934, 2000-06-25

被引用文献数

1

---

For the purpose of establishing the mathematical beckground of a kinematic analysis of a multiple body system, the Lie aglebra of a motion group has been studied, and the algebraic experessions for kinematic analysis which is applicable any motion group is determined. Firstly it is shown that the equations for determining relative velocities and accelerations among rigid bodies can be expressed by the Lie algebra of addition and commutator product representing a Lie algebra of a motion group. Next, it is also clarified that the velocity and the acceleration of the point on a rigid body in a motion can be computed by multiplying an function of elements of the Lie algebra to the vector indicating the point from the left side. There exist eight groups of the rigid body motion, and the characteristics of the motin groups can be described by the theory of Lie algebra.

著者

三村 宣治 小野寺 良二

出版者

日本機械学会

雑誌

日本機械学会論文集. C編 (ISSN:03875024)

巻号頁・発行日

vol.71, no.707, pp.2218-2224, 2005-07-25

被引用文献数

3

---

There is a method of measuring a shake and vibration quantiatively and evaluating, in one of the performance evaluations of a moving object like vehicles. In that case, the acceleration information as an amount of physics of a shake and vibration becomes important. Furthermore, the acceleration information on 6 DOF is needed when measuring complicated motion of vehicles etc. Then, we constructed 6 DOF acceleration sensor system which used three dual-axis accelerometers, and enabled measurement 6 DOF acceleration. In this paper, we analyzed the problem of the stability in the measurement system of the same method that was not clearly analyzed in the past research. We took notics of a nonlinear term that consist of an angular velocity, which included in the derivation algorithm of 6 DOF acceleration, and made clearly how a nonlinear term would influence the stability of a measurement system by the analysis simulation. And we installed the acceleration sensor in vehicles and performed measuring 6 DOF acceleration to a slalom run. As a result of comparing survey data with a simulation data, emission of the measurement system under the influence of a nonlinear term was not seen.

著者

中嶋 秀朗 中野 栄二

出版者

一般社団法人日本機械学会

雑誌

日本機械学会論文集. C編 (ISSN:03875024)

巻号頁・発行日

vol.72, no.721, pp.2926-2931, 2006-09-25

参考文献数

5

被引用文献数

5

---

A leg-wheel robot has mechanically separated four legs and two wheels, and it performs high mobility and stability on rough terrains. In this paper, the strategy for the leg-wheel robot moving over large rough terrains is described. First, topographical features are classified for the large rough terrain movement. They are classified into 13 patterns by the combination of terrain surfaces. In order to move over all classified terrains, three gaits are proposed as adaptive gait for large rough terrain. Those three gaits are as follows: 1. Gait for an upward step: the forefoot landing point is higher than contact points with the ground of wheels, and the robot raises the body toward the forefoot landing point. 2. Gait for a downward step: the forefoot landing point is lower than contact points with the ground of wheels, and the robot lowers the body toward the forefoot landing point. 3. Gait for getting over an obstacle: the forefoot landing point is not higher than contact points with the ground of wheels, but the robot raises the body as high as possible.