著者

多田 宏次郎 師岡 愼一

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 (ISSN:21879761)

巻号頁・発行日

vol.83, no.850, pp.16-00577-16-00577, 2017 (Released:2017-06-25)

参考文献数

18

被引用文献数

1

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This paper presents the pressure drop prediction of BWR fuel assembly without experiment. To evaluate the core performance, pressure drop of fuel assembly is one of the key design parameters. The shape of fuel assembly is complicated and the spacer has a strong effect on pressure drop. Therefore, to obtain the pressure drop of fuel assembly, the experiments are needed. However, the experiments need a lot of time and money. In the authors' previous study, the friction coefficient and spacer loss coefficient under single phase flow condition were evaluated using CFD analysis and total pressure drop under two phase flow condition were predicted using these coefficients and verified by the data of the tight lattice bundle. The purpose of this study is to predict the pressure drop of BWR fuel assembly without experiments. The predicted pressure drop by the previous study's method was compared with the pressure drop data for full-scale high-burnup 8x8 fuel assembly covering the operating BWR conditions. The following conclusions are obtained; (1)The average and standard deviations of prediction accuracy (calculation/experiment) were 1.046 and 0.023, (2)The prediction accuracy of this method is almost same as that of the current BWR design method.

著者

北村 健三 光石 暁彦 鈴木 孝司

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.83, no.850, pp.16-00542-16-00542, 2017 (Released:2017-06-25)

参考文献数

16

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The natural convective flow and heat transfer of air induced around an inclined row of heated horizontal cylinders have been investigated experimentally. The experiments were carried out with the ten-cylinders row placed in the plane of inclination angles θ=0°, 30°, 45°, 60°, 75° and 90° from horizontal. The cylinders in the row were heated with constant heat flux and their diameter d and gap G were varied as d=8.4, 14.4mm and G=3.6 to 20.6mm. The Nusselt numbers Nud from the cylinders in the row were measured. They showed maxima and minima for the horizontal and vertical rows, while intermediate Nusselt numbers were obtained for the inclined rows. Those Nusselt numbers were next converted to the gap-based Nusselt numbers NuG, and, then, rearranged with the non-dimensional parameter RaG*(G/d). The result showed that the Nusselt numbers NuG are predicted well with the parameter RaG*(G/d) for the whole rows of inclination angle from horizontal to vertical.

著者

上杉 康登 山崎 由大 金子 成彦 疋田 孝幸 津村 雄一郎 水野 沙織

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.83, no.850, pp.16-00537-16-00537, 2017 (Released:2017-06-25)

参考文献数

15

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To predict the combustion characteristic of auto ignition combustion in internal combustion engines, it is necessary to consider the inhomogeneity of the fuel, EGR and air in the mixture. In this research, a PDF (Probability Density Function) combustion model considering the influence of the inhomogeneity of mixture on the auto ignition combustion is developed. In our approach, the PDF of the injected fuel and the EGR gas is predicted by two-zone turbulent mixing model and only the PDF at the top dead center of the combustion stroke is used to calculate combustion characteristic to realize the reasonable calculation time for the control system design tool. The prediction model was validated by comparing with the experimental result for various injection timings and EGR ratios. It found that the model can qualitatively predict the combustion characteristics with reasonable calculation time.

著者

相原 洋人 田中 信雄

出版者

一般社団法人 日本機械学会

雑誌

Dynamics & Design Conference 2007 (ISSN:24242993)

巻号頁・発行日

pp._340-1_-_340-6_, 2007-09-25 (Released:2017-06-19)

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There have been a number of reports on active noise control (ANC). However, conventional ANC using a voice coil loudspeaker promises attenuation only at targeted local points. Then ANC using a parametric array loudspeaker as a control source is discussed. A parametric array loudspeaker exploits nonlinear interactions of finite amplitude ultrasounds in the air. Characteristics of a parametric array loudspeaker have already been reported by a number of researchers. However, there are few investigations of simulation or experimental result of ANC using a parametric array loudspeaker. This paper addresses control effect of feed forward ANC using a parametric speaker as a control source. The control effect is more than 20dB by ANC using a parametric array loudspeaker as a control source at 1000Hz. Distribution maps of sound pressure of ANC using a conventional speaker and a parametric speaker as a control source are shown by numerical analyses and experiments.

著者

栩谷 吉郎 川北 英貴

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.83, no.850, pp.16-00528-16-00528, 2017 (Released:2017-06-25)

参考文献数

8

被引用文献数

1

---

An experimental study has been carried out to clarify the effect of quantity of absorbed water on behaviour of single silica-gel particles in oil with dc electric field, as a basic research to augment adsorption. The progress of adsorption changes mass and physical properties of a silica-gel particle, and the change might influence the behaviour of the particle. The experiment is conducted under condition that the adsorbed material is only water, and the quantity of water is adjusted beforehand to prescribed value. Two electrode plates are horizontally set up 40 mm apart in silicone oil. Particle diameter is adopted of 2.7, 4.0 and 5.0 mm, and the range of applied voltage is 0 - 28 kV. The applied voltage is increased at approximately 2kV/min. Observation of behaviour of a silica-gel particle starts from resting condition on a lower electrode. As a result, a dried silica-gel particle does not begin moving even at the maximum voltage. For a silica-gel particle of water adsorbed, following four stages have been observed, excluding a very few exceptions; rise from the upper side of lower electrode to the upper electrode, bound and rest on the lower side of the upper electrode, descent to the lower electrode, and bound and rest on the lower electrode. The rest time on the electrode is not seen to a completely water-absorbed silica-gel particle. It is thought that the particle exchange the electric charge at the rest time. The applied voltage for the leave of a silica-gel particle from the lower electrode, rest time on each electrode, and bound height from each electrode are also shown.

著者

森 賢斗 駒田 佳介 植木 弘信

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.83, no.850, pp.16-00507-16-00507, 2017 (Released:2017-06-25)

参考文献数

20

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A laser 2-focus velocimeter (L2F) was used for measurements of velocity and size of droplets in diesel fuel sprays. Diesel fuel was injected intermittently into the atmosphere by using a 8-hole injector nozzle. The diameter of the nozzle orifice was 0.112mm. The rail pressure was set at 65MPa by using a common rail system. The period of injector solenoid energizing was set at 2.3ms. The L2F had a micro-scale probe which consists of two foci. The focal diameter was about 3μm, and the distance between two foci was 20μm. The data sampling rate of the L2F system was markedly high as 15MHz. L2F measurement was conducted at 10mm downstream from the nozzle exit. Temporal and spatial changes in the velocity, size and number of droplets inside sprays were investigated. Spray images were taken by using a 180ns spark light source, and the scattered light intensity distribution and spray width were estimated. The scattered light intensity, the spray width and the number of droplets were oscillated several times in the injection period. The number of droplets at the inner region of the spray decreased and the one at the outer region of the spray increased, when the spray width increased. That is, many droplets fly to the outer region of the spray at the time when spray width is wide.

著者

玉木 伸茂 室谷 拓也 原田 貴人

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.83, no.850, pp.16-00500-16-00500, 2017 (Released:2017-06-25)

参考文献数

20

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It is important to improve spray characteristics of an energy conversion engine in order to reduce carbon dioxide and exhaust gas emission. The purpose of this study is to design and develop high-dispersion injection nozzle for direct injection Diesel engine. This paper describes about that effects of the measurement and the geometric shapes of nozzles on spray characteristics and design of the nozzle which is obtained more excellent spray characteristics. When the measurement, the geometric shapes and the internal structure of nozzle were designed the most suitable conditions, breakup length becomes approximately 10 % shorter and spread of spray i.e., spray angle becomes large about 30 %. Moreover, Sauter mean diameter obtained is about order of 10 μm which is smaller than that with the nozzle developed in the previous study.

著者

宗意 奎太郎 杉田 勝彦 梅沢 修一 川島 久宜 石間 経章

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.83, no.850, pp.17-00054-17-00054, 2017 (Released:2017-06-25)

参考文献数

13

被引用文献数

1

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Water spray is used for cooling suction air of gas turbine for power augmentation. Cooling efficiency depends on the spraying properties. The aim of this study is to investigate the spray characteristics and the influence of secular change in the spray nozzle. PDA (Phase Doppler Anemometry) measurements are conducted at each cross section in wind tunnel which is scale model of inlet duct. Pin type nozzles and a hole type nozzle are tested. Same type nozzles with different using period are also tested. The nozzles are new one and old one which is used 1750 hours before the spray experiments. The spray properties in high spatial-temporal resolution are provided by the PDA. As a result, the droplet size by a pin type nozzle has no change after 1750 hours. The data rate, velocity and flow rate decrease after 1750 hours due to increase of the passage resistance by filter clogged. Pin type nozzles have asymmetry shape in data rate distribution due to the existence of pin. The SMD distributions by pin type nozzles have flat shape in the measurement region. The SMD distributions gradually increase in the value from the center to outer in hole type nozzle. Droplet size dispersion at each measuring point for all nozzles are also evaluated by the experiment. Dispersion of diameter increase in from the center to outer in a hole type nozzle. Also cooling efficiency and the relations of particle density are evaluated. If the particle density is high, the cooling efficiency become small even if the particles have small diameter and high velocity.

著者

稲垣 大志 中村 暢志 板野 智昭 関 眞佐子 兵頭 仁介

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.83, no.850, pp.17-00042-17-00042, 2017 (Released:2017-06-25)

参考文献数

10

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The water velocity field in a rectangular reservoir driven by a previously unexplored water streamer is investigated experimentally and numerically. Firstly, the velocity field on the water surface induced in a rectangular reservoir is estimated from trajectories of floating passive tracers. Secondly, the velocity at the several fixed points below the surface is directly measured with the aid of an electro-magnetic velocimetry. These measurements elucidate that the streamer activates an underwater circulation between the surface and the bottom in the reservoir. Additionally, a numerical simulation is examined to realise the induced three-dimensional flow below the water surface. The obtained results provide an evidence that the induced flow structure is three-dimensionally spiral, which is distinct from that induced by the water streamers traditionally utilized in aquacultural reservoirs. The investigated streamer may be utilized for the purpose to particularly enhance the underwater vertical mixing in aquacultural reservoir or purification plant.

著者

姜 東赫 佐藤 光太郎 横田 和彦

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 (ISSN:21879761)

巻号頁・発行日

vol.83, no.850, pp.17-00038-17-00038, 2017 (Released:2017-06-25)

参考文献数

15

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The present study investigates a swirl flow instability induced by a rotating cylinder between coaxial two disks as a model of a vaneless diffuser at zero flow rate. To begin with, the experiment and three-dimensional finite volume simulation were performed. The rotating cylinder was used to produce the swirl flow. Small vortices were generated from the cylinder surface. They were combing and forming one croissant-shaped toroidal vortex (CTV), which was rotating around the cylinder. Small vortices were separating from the CTV and flowing away from the cylinder. In order to investigate the cause of the swirl flow instability, a 2D stability analysis for an annular vortex street was performed. The annular vortex street became less unstable for the larger radial location and the fewer number of vortices. This implies that the vortices could be forming into one vortex as their radial locations increased. In order to validate the stability analysis, the vortex simulations were carried out. The vortices generated from the cylinder surface were forming into one cell as their radial locations increased. In order to validate the stability analysis and vortex simulation, the 2D finite volume simulation was performed. The vortices were generated from the cylinder surface. They were combining and forming one cell, which was rotating around the cylinder. The vortices were separating from one cell and flowing away from the cylinder. The frequencies of vortex rotation agreed in the experiment, the two and three-dimensional simulations. Therefore, it is considered that the 2D vortex transforms to the 3D CTV, similarly the Tayler vortex. Furthermore, all the results indicate that the 2D swirl flow instability causes the CTV, and the vortices combining to and separating from the CTV.

著者

高橋 護 岩野 耕治 酒井 康彦 伊藤 靖仁

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.83, no.850, pp.17-00004-17-00004, 2017 (Released:2017-06-25)

参考文献数

26

被引用文献数

1

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Simultaneous measurement of the velocity-gradient and fluctuating static pressure was carried out in a turbulent planar jet. We use a constant-temperature hot-wire anemometry and a miniature pressure probe for velocity measurement and fluctuating static pressure measurement, respectively. Two types of the combined probe are introduced for simultaneous measurement of the velocity-gradient and fluctuating static pressure. One consists of an X-type hot-wire probe and a pressure probe and the other consists of two I-type hot-wire probes arranged in vertical direction and a pressure probe. For improvement of the measurement accuracy, the responsivity of the pressure probe, the time-lag due to the spatial distance between the hot-wire probe and the pressure probe, and the attenuation of the velocity-gradient measurement due to the finite difference method, are corrected. In this paper, we compare the various statistics of the turbulent planar jet acquired using the combined probes and those acquired using hot-wire probe or pressure probe alone. Through the results, it is confirmed that the simultaneous measurements were well-performed in the turbulent planar jet expect for the outside of the velocity half-width. Further, it is revealed that the Pressure Rate-of-Strain Correlation, which appears in the Reynolds stress transport equation, is almost dominated by (p´/ρ)(∂u´2/∂x1) and (p´/ρ)(∂u´1/∂x2) barely contributes to the Reynolds stress transport in the cases of Re ≥ 10,000.

著者

江尻 英治 岩楯 智哉

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.83, no.850, pp.16-00484-16-00484, 2017 (Released:2017-06-25)

参考文献数

16

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The straight-bladed vertical axis wind turbine is one of the promising candidates for next-generation power sources because of its high efficiency, quiet operation and structural simplicity. Fewer wind turbines of this type have been manufactured and used so far compared with other types like the horizontal type. Therefore, further improvement in efficiency is essential in order to promote their widespread use. The purpose of this study is to better understand the influence of the blade profile of the straight-bladed vertical axis wind turbine on flow and aerodynamic performance and to improve wind turbine efficiency. Unsteady two-dimensional flow through a wind turbine with a symmetrical blade profile, the diameter of which was 3 m, was numerically computed with a commercial CFD code and the results were analyzed. A wind turbine with outward-cambered blades was then designed in order to increase the rotational force acting on the blade along with a wind turbine with inward-cambered blades for comparison. The computational results showed that the wind turbine with outward-cambered blades was better in performance than the ones with symmetrical or inward-cambered blades. Experiments using small wind turbine models, the diameter of which was 200 mm, were carried out in order to verify the computational results. The experimental results showed the same tendencies as the computational results in spite of the difference in scale, Reynolds number and blade number. The effects on flow and performance were also analyzed by additional computations performed with the same CFD code.

著者

則竹 茂年 中野 冠 木村 文彦

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.72, no.724, pp.3955-3961, 2006-12-25 (Released:2011-03-04)

参考文献数

9

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As manufacturing activities have been widely globalized, it is becoming more and more difficult to respond to changes quickly. It is also important to take a positive stand against environmental issues to pursue the sustainability of the global environment without wasting resources related to production activities. The purpose of this paper is to establish a lifecycle-oriented design method of production systems. For this end, we have developed prototype system for life-cycle simulator, which is constructed by a demand scenario generation module and a simulation assessment module. We also conducted a simple comparative experiment taking two configuration plans for a transfer line and a cell line as examples in order to verify the effectiveness of this proposed technology.

著者

池田 博和 松浦 文生 越塚 誠一 岡 芳明

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 B編 (ISSN:03875016)

巻号頁・発行日

vol.64, no.624, pp.2431-2437, 1998-08-25 (Released:2008-03-28)

参考文献数

13

被引用文献数

2 7

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Fragmentation of liquid metal takes place as basic processes of vapor explosions. This leads to rapid evaporation on the stretched interface. To date, a number of models explaining the fragmentation mechanisms have been proposed. However, few evidence has been obtained from the experiment because the phenomena are rapid. In Moving Particle Semi-implicit (MPS) method, grids are not necessary so that fluid fragmentation as well as multi-fluid thermal hydraulics can be analyzed. A numerical model of evaporation is developed for the present study. Impingement of water jets on a liquid metal pool is analyzed using the MPS method to investigate two typical models explaining the fragmentation mechanisms : Kim-Corradini and Ciccarelli-Frost models. Penetration of the water jet, which is assumed in Kim-Corradini model, is not observed in the calculation results. A filament of the liquid metal is observed between two water jets as assumed in Ciccarelli-Frost model. The filament appears when the jet density is smaller than the pool density, while the penetration appears when the jet density is hypotheticaly larger. The usual combinations of densities in vapor explosions are in the region of Ciccarelli-Frost model.

著者

倉光 貴之 藤井 達也 蓮沼 将太 小川 武史 禹 明勲 高梨 正祐

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.83, no.850, pp.17-00066-17-00066, 2017 (Released:2017-06-25)

参考文献数

12

被引用文献数

1

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The purpose of this study is to investigate low cycle fatigue (LCF) and high cycle fatigue (HCF) strengths, crack initiation and growth behaviors of Ni based castalloy 246. LCF and HCF tests are conducted under load controlled conditions. As the result of the observation of etched specimen, the grain size is from 3 mm to 5 mm. And the microstructure is mainly composed of dendritic structure. Growth orientation of dendritic structure varies in every grain. The result of elemental analysis, Si and Ti are detected at dendritic boundary. The results of LCF test show that small cracks initiate at the first cycle, followed by the crack growth along slip direction. Observation of fracture surface reveals that small cracks originate at casting defect or dendritic boundary. The results of HCF, on the other hand, show that small cracks initiate from subsurface casting defect under Δσ ≦ 600 MPa, while fracture origin becomes surface under Δσ > 600 MPa. The result of HCF test after introducing small crack on the surface shows that small crack on the surface does not affect on the fatigue life and the location of crack initiation. As the result of EBSD, the crack initiation site is near grain boundary and the crack grows along slip plane.

著者

風間 恵介 川勝 俊輝 赤木 康宏 毛利 宏

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.83, no.849, pp.17-00014-17-00014, 2017 (Released:2017-05-25)

参考文献数

17

被引用文献数

2

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This paper describes the development of a new localization method using a simple 2D map. The general method for localization using a 2D map is to match between the boundary line on the 2D map and the detected boundaries in the real world, i.e. lane markers, walls of building, or curbs. It is necessary to create a differential process in order to detect boundary lines of the road. If these methods try to detect small changes, the false-detection rate increases due to enhanced noises; if they try to reduce the effect of noise, boundary lines are misdetected. The estimation result of this method deteriorates drastically if the false-detection or misdetection of the boundary line occurs. We propose the new localization method based on the road area detection. First, the road map is extracted from the boundary lines on a 2D map. Next, the road plane image is made by the road area detected using LiDAR in the real world. Finally, the road map and the road plane image are matched by image registration. We confirmed that the proposed method have accurate estimation performance with several noise and low-cost calculation from the simulation. And we conducted the performance validation of proposed method in the real world. As a result, we confirmed the same tendency as simulation results.

著者

鈴木 新一 森田 康之 坂上 賢一

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 A編 (ISSN:03875008)

巻号頁・発行日

vol.67, no.655, pp.432-439, 2001-03-25 (Released:2008-02-21)

参考文献数

24

被引用文献数

3 4

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High-speed holographic microscopy is applied to take successive microscopic photographs of a fast propagating crack at bifurcation. The crack speed is about 650 m/s. From the photographs, crack opening displacements (CODs) of the mother crack and two bifurcated branches are measured along the crack. A specimen with a notch is also made, where the notch has the bifurcated notch tip same as the bifurcated fast propagating crack. Opening displacement of the notch is measured by Moire interferometry under static loading condition. The measurement results show that the opening displacements of both the mother crack of the bifurcated fast propagating crack and the mother notch of the bifurcated notch are proportional to square root of the distance r from the crack or the notch tip. The opening displacements of the two bifurcated branches of the notch are also proportional to √(r). But the CODs of the bifurcated branches of the fast propagating crack are not always proportional to √(r).

著者

田中 克則 若林 哲 木村 修一

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 (ISSN:21879761)

巻号頁・発行日

vol.83, no.849, pp.16-00487-16-00487, 2017 (Released:2017-05-25)

参考文献数

9

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Car shake is a vehicle vibration that occurs when a passenger car runs on a smooth road, and it causes dissatisfaction of a customer who purchased the passenger car. RFV that stands for radial force variation is defined in ISO 13326 and JIS D4233. RRO that stands for radial run out is variation of the rim diameter. RFV and RRO become the cause of car shake. Tire wheel RFV is measured by using a mass production road wheel, tire RFV is measured by using an accurate measuring road wheel. Car manufactures decide control values such as tire wheel RFV, tire RFV and wheel RRO to reduce car shake. And the control values are presented to production sectors, tire manufactures and road wheel manufactures. The relationship among tire wheel RFV, tire RFV and wheel RRO is evaluated experimentally to decide the control values. A mechanical model of tire wheel RFV that can calculate from tire RFV and wheel RRO is needed to decide appropriate control values. There are some technical papers of tire RFV that is managed by tire manufactures, but there are few technical papers of tire wheel RFV that is managed by car manufactures. In this study, a mechanical model that can calculate tire wheel RFV were developed to reduce car shake. This model has the following features. The parameters are the tire RFV and the value multiplied by wheel RRO and tire stiffness. This model is based on the complex plane and the Monte Carlo calculations. By using the complex plane, the model can calculate the relationship between tire wheel RFV and the assembly condition. By using the Monte Carlo method, the model can calculate average and standard deviation of tire wheel RFV.

著者

坂 真澄 巨 陽

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 A編 (ISSN:03875008)

巻号頁・発行日

vol.65, no.639, pp.2193-2198, 1999-11-25 (Released:2008-02-21)

参考文献数

24

著者

久代 育生 鈴木 桂輔

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.83, no.849, pp.16-00437-16-00437, 2017 (Released:2017-05-25)

参考文献数

30

被引用文献数

1

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The steering feel is an important technical problem for handling and drivability of driver-vehicle system and various kinds of studies have been conducted. The objective evaluation is a key factor to construct model base design process for the steering feel. Many kinds of objective evaluation criteria for the steering feel have been proposed using steering-angle input. However, these objective evaluation criteria for the steering feel should be based on driver's steering operation. The steering responses using steering torque sinusoidal input are similar to the minimum-jerk model of human operation. This study proposes objective evaluation criteria for the steering feel using steering responses by steering-torque sinusoidal input test. From the characteristics of steering torque and steering angle, and the characteristics of steering torque and yaw velocity, the objective evaluation criteria for the steering feel are proposed. For example, the increasing characteristics and the decreasing characteristics for steering torque, hysteresis and linearity of steering angle and yaw-velocity response are evaluation criteria. The objective evaluation criteria by steering torque input shows another aspect of steering characteristics because of changing steering angle response under the influence of vehicle dynamics and steering system dynamics.