著者

古賀 倫子 佐藤 太一 松野 隆太 蔭山 怜

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.855, pp.17-00220-17-00220, 2017 (Released:2017-11-25)

参考文献数

9

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We investigated the damping mechanism of a granular material damping system applied to reducing vibration in structures that have a high natural frequency and small vibration displacement. Experiments were conducted under several conditions of total mass of granules. We also constructed a computational model of a single-degree-of-freedom vibration system with a granular material damper to study the mechanism of a granular material damping system. On the basis of the fundamental idea that the damping effect of a granular material damper is governed by the motion of the granules, we classified the granular materials as “relative motion mass” and “equivalent added mass” in the translational motion and as “rotating mass” and “not rotating mass” in the rotational motion and then considered the relationship of these mass classes to the damping characteristics. In this report, we examine the relationships of the motion of the granular materials, “relative motion mass” and “rotating mass”, and damping ratio by means of experiments and calculations for structures that have a high natural frequency and small vibration displacement.

著者

藤田 勝久 森朝 昭典

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.855, pp.17-00206-17-00206, 2017 (Released:2017-11-25)

参考文献数

10

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In this paper, dynamic stability analysis methods of a beam subjected to a confined annular axial flow are dealt with. Such structures are submarine resources production pipeline, reactor core structures of nuclear power plants, high-speed trains passing thorough a tunnel, a piping system in the field of ocean mining, and so on. The relation between the annular axial flow velocity and the unstable dynamics of structures are clarified. We have compared two analysis methods which can evaluate the dynamic instability of such structures. In first analysis method, the fluid is treated as viscous fluid, and is governed by the Navier-Stokes equation, and the beam structure is treated as the Euler-Bernoulli beam. This is called as the viscous fluid solution namely NS solution hereafter. In second analysis method reported by (Rinaldi and Paidoussis, 2012), the fluid is treated as ideal fluid. Then the viscosity effect is added to the equation of motion. This is called as the ideal fluid solution namely R&P solution hereafter. The complex eigenvalue analysis of the fluid structure coupled equation of motion is performed in order to clear up the dynamic instability. Performing the parametric studies, the comparison between both solutions is investigated. When the fluid viscosity becomes large, the difference in the critical velocity between the viscous fluid solution namely NS solution and the ideal fluid solution namely R&P solution is found to be generated. The destabilization effect appears due to the fluid viscosity force terms of the added stiffness of the fluid-structure coupled equation only in the viscous fluid solution.

著者

金子 康智 渡邉 敏生 前田 茂稔 鷲尾 宰司

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.855, pp.17-00184-17-00184, 2017 (Released:2017-11-25)

参考文献数

22

被引用文献数

3

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Although bladed disks of turbomachinery are nominally designed to be cyclically symmetric (tuned system), the vibration characteristics of all blades on a disk are slightly different due to the manufacturing tolerance, the deviation of the material property, the wear during operation, and so on. These small variations break the cyclic symmetry, and split the eigenvalue pairs. The actual bladed disks with the small variations are referred to a mistuned system. Many researchers have studied mistuning, and main conclusions are while mistuning has an undesirable effect on the forced response, it has a beneficial (stabilizing) effect on the blade flutter (the self-excited vibration). Although such mistuning phenomena of bladed disks have been studied since 1980s, almost all studies focused on the amplification factor of the displacement response, and few studies researched the amplification factor of the vibratory stress response. Therefore, in the previous paper, authors studied the amplification factor expressed by the vibratory stress for the lower modes of the bladed disk, using the simple assumption. In this study, the mistuning effect expressed by the vibratory stress for the lower and higher modes are examined, using the reduced order model without any assumptions. First, formulation for evaluating the mistuning effect expressed by the vibratory stress is derived, using the reduced order model SNM (Subset of Nominal Modes). Second, the frequency response analysis of the mistuned simple bladed disk consisting of flat plates is carried out systematically. Finally, comparing the amplification factor of the displacement response with that of the vibratory stress response including the synthesized stress (Mises stress and the principal stress), mistuning phenomena expressed by the vibratory stress are clarified.

著者

篠崎 貴宏 本家 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 (ISSN:21879761)

巻号頁・発行日

vol.83, no.855, pp.17-00176-17-00176, 2017 (Released:2017-11-25)

参考文献数

13

被引用文献数

1

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This paper proposes identification method of excitation force of rigid body vibration source by physical model identification. If the reworking occurs after the assembly of the prototype in mechanical product, the cost increases due to the retrofit countermeasures and development period extension. Pre-prediction of vibration at the design stage is important to avoid these problems. Prior prediction of vibration needs to grasp the excitation force of the vibration source. As conventional methods, the mount stiffness method and the matrix inversion method have been proposed. However, mount stiffness method calculates the mount transmission force. Therefore, if the development machine changes the structure, preliminary evaluation does not apply. The matrix inversion method can solve this problem. However, when the frequency response function contains a measurement error, the error spreading propagates in inverse matrix calculation. Therefore, in order to avoid the inverse matrix calculation, we propose identification method of excitation force of rigid body vibration source by physical model identification. In this paper, it was investigated features of the inverse matrix method and the identification method of excitation force by physical model identification using the basic experiment. As a result of study, the method by physical model identification showed that the influence of measurement error is smaller than the matrix inversion method. In addition, it showed that it is possible to identify the excitation force with fewer excitation points than the matrix inversion method.

著者

本家 浩一 増田 京子 次橋 一樹 杉本 明男

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.83, no.855, pp.17-00173-17-00173, 2017 (Released:2017-11-25)

参考文献数

9

---

The Impact damper with granular materials has a high damping effect for wide frequency range and it is used in many fields. Many researches have been made on the prediction of the damping effect of this damper on one degree of freedom spring-mass system. But it is more useful to be able to predict the damping effect when applied to a real complex structure. For this purpose, numerical modeling of damping effect of an impact damper is important for efficient design of structures set with dampers. In this paper, the granular materials are modeled as one mass point of restitution coefficient of zero that undergo displacement vibration excitation, and the motion of this mass point is theoretically analyzed for the case of vertical vibration and one side collision. From these results, we propose a method for obtaining the macroscopic damping effect of the impact damper with granular materials. This is obtained as a nonlinear equivalent mass ratio and nonlinear damping coefficient with amplitude dependence. Further the excitation experiment which identified the damping characteristic of the damper was carried out. Theoretical solution and experimental result show the good coincidence.

著者

澤野 宏 松本 拓也

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.855, pp.17-00127-17-00127, 2017 (Released:2017-11-25)

参考文献数

9

---

Demands for machining of three-dimensional (3D) complex geometries over a large area with nanometer scale accuracy have recently increased in the various industrial sectors. In order to meet such requirements, it is necessary to realize not only a machine tool with nanometer scale machining accuracy, but also a coordinate measuring machine with a nanometer scale measuring resolution for evaluating the machined parts profile. A scanning tunneling microscopy (STM) and atomic force microscope (AFM) probes have a high measuring resolution. However, in the STM, the specimen to be measured needs to have conductivity, and the AFM cannot measure a step shape or a slope. It is thought that the application of the profile measurement by the AFM probe can be expanded, by development the AFM probe suitable for the measurement of the slope shape. Therefore, this study proposed a novel AFM probe suitable for measuring the slope shape by using a low rigidity spring. In addition, the basic characteristics of the proposed AFM probe was experimentally investigated. Investigation results confirmed that the proposed AFM probe can detect atomic forces acting between the specimen and the probe.

著者

武藤 大輔 高野 靖 山口 誉夫

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.855, pp.17-00106-17-00106, 2017 (Released:2017-11-25)

参考文献数

11

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To increase the noise proof performance of a cover with aperture excited by diffuse acoustic fields from the outside, it is a problem to prevent the occurrence of the inner acoustic mode at the lower frequencies. Authors had suggested the feed forward active noise control (ANC) for the acoustic field inside the cover. Diffuse acoustic field excitation experiment using reverberant room has been examined to comprehend acoustic characteristics inside the cover. The results show that the inner cover field is in the state of locally coherent at the frequencies of inner acoustic mode, so that it is good environment for the active noise control. Then, a calculation with two-dimensional finite difference time domain (FDTD) method has been done to examine the feasibility of feed forward ANC. The results show that it is possible to realize ANC for the acoustic field inside the cover by proper design of control filter. Finally, experimental measurement of diffuse acoustic field excitation in the reverberant room has been done again to examine the ANC with the design method mentioned above. The results show that feed forward ANC can reduce noise level by 5dB at the peak frequency caused by the inner acoustic mode. Furthermore, the inner acoustic pressure distribution is also reduced uniformly at the frequency. Therefore, it is concluded that it is possible to realize feed forward active noise control for the acoustic field inside the cover with aperture excited by diffuse acoustic fields from the outside, even if the excitation is random or the causality of I/O is not satisfied.

著者

渡辺 亨

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.855, pp.17-pre05-17-pre05, 2017 (Released:2017-11-25)

著者

大津 健史 小松 恭一 橋村 真治 今戸 啓二

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 (ISSN:21879761)

巻号頁・発行日

vol.83, no.855, pp.17-00319-17-00319, 2017 (Released:2017-11-25)

参考文献数

27

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This paper describes that the film formation and shear properties of screw tightening lubricant PIB (Polyisobutylene) under the oil starvation condition. The point contacted pure sliding tests were conducted, and the film thickness was measured using the interferometry method with the spacer layer. The result showed that the starvation region occurred at the inlet of the conjunction becomes large with time. It was also shown in the initial time of the test that the film thickness decreases due to the oil starvation, however, the thickness is thicker than the value equivalent to surface roughness. The friction coefficient depended on the starved area, and that showed the constant value of 0.16-0.17 in the fully starved condition. The relationship between the friction coefficient and the shear rate suggested that the coefficient in the high shear rate condition is the constant value, that revealed the film may be changed to the solid like film with the high shear strength in the fully starved condition. The long term test showed that the breakdown of film is appeared at about 120 s and then the wear area expands in the remainder of the test. The test results suggested that the PIB lubrication film has the high shear strength and enable to protect the contact surface in the tightening screw from the direct contact and the wear.

著者

加藤 秀治 伊藤 江平 北村 明大 池永 訓昭 久保田 和幸

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.855, pp.17-00258-17-00258, 2017 (Released:2017-11-25)

参考文献数

12

被引用文献数

1

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Recently, a titanium alloy has been as biomaterials that have stable mechanical property and superior biocompatibility. But the titanium alloy generally has higher young’s modulus in comparison with cortical bone, then bone resorption was occurred by stress shielding. For this reason β-type titanium alloy exhibiting super-elasticity and super-plasticity was developed. This alloy has high tensile stress and low young’s modulus too. However, the characteristics of this alloy is lost by severe heat environment and external force. Therefore, there is possibility that the advantageous characteristics may be lost during cutting. In this study, the effect of cutting temperature and cutting force on the affected layer was investigated by milling with small ball end mill tool in order to decrease the affected layer by cutting process. At the cutting speed of 16.0m/s, the thickness of the affected layer exceeded 2.5μm because of increasing of cutting temperature that approached to the neighborhood of transition temperature of this alloy. On the other hand, the affected layer was observed for the cutting condition of high cutting force by increasing feed rate of a tooth, depth of cut and pick feed, the thickness of the affected layer was 0.7μm .So, the affected layer was dominant by the influence of cutting temperature. To decreasing affected layer, the cutting temperature is able to decrease to decreasing feed rate of a tooth or depth of cut.

著者

河合 貴未央 Beaucamp Anthony 今泉 紀幸 櫻井 正俊 竹内 芳美

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.855, pp.17-00162-17-00162, 2017 (Released:2017-11-25)

参考文献数

11

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In recent years, the drill used to make holes is expected to exert both high machining accuracy and good processing capability. In order to meet those requirements, it is necessary to develop a new drill shape with good properties requested by designers. There is a strong need for a new system to shorten the drill fabrication time, to reduce material costs, and to create new drill configurations by predicting their characteristics. Current drill shape prediction systems cannot comprehensively and mathematically treat drill cross-section shape including the cutting edge, groove and so on. The prediction system would become more practical if the drill specification was mathematically formulated. This study reports the development of a system to predict not only the cross-sectional shape but also various parameters from the information of grinding wheels used in drill fabrication. Furthermore, this study proposes the new system to predict the most suitable grinding wheel setting from the grinding wheel shape and some drill specifications as the reverse process.

著者

廣垣 俊樹 青山 栄一 杉浦 義久 小林 飛翔

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.855, pp.17-00132-17-00132, 2017 (Released:2017-11-25)

参考文献数

14

被引用文献数

3

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The purpose of this study is to construct the automation technology based on the hammering task and its sound feedback with an industrial humanoid robot equipped with an integrated system of vision, sound and dual arm motion. First, we discuss a suitable flexible rubber stick to achieve the hammering task and developed the acoustic recognition system based on its hit sounds. Second, we confirm that the developed system is sufficient to investigate the task playing the glockenspiel, and also discuss the characteristics of motion based on dual arm motion. Third, we attempt to cooperate with hammering the bottle and pouring liquid into it based on estimating its hit sound. As a result, it can be seen that the proposed system using an industrial humanoid robot achieves sufficient motion accuracy. Therefore it is demonstrated that the proposed approach is found to be effective to construct the automation technology based on the hammering task and its sound feedback with an industrial humanoid robot.

著者

西津 卓史 谷次 智弥 竹澤 晃弘 米倉 一男 渡邊 修 北村 充

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.855, pp.16-00581-16-00581, 2017 (Released:2017-11-25)

参考文献数

19

被引用文献数

2

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Structure can get various mechanical characteristics by applying periodic structures as typified by lattice structures. Lattice structures are generally used inside the structural member in order to reduce the weight. One advantage of lattice structures is that we do not need to change the whole structural shape when we replace the solid part of a component with the lattice structures. Another advantage is the lightness of the weight, and hence it is important to design a high performance lattice shape with low weight. However, a framework for development of micro lattice structures considering both stiffness and weight has not been established. Thus, we propose a method for designing and producing micro lattice structures. We use a topology optimization method for a designing methodology. Topology optimization is an effective method in designing high performance lattice structure since topology optimization allows us to change the topology and to design a complicated shape. We use a metal additive manufacturing (AM) machine for producing the optimal lattice structures. AM allows us to produce a complicated structure which removal and forming manufacturing cannot produce. We use a bulk modulus as the objective function since it is one of the important mechanical characteristics in design. In this research, we use a homogenization method to compute the bulk modulus. Objective function was modified so that isotropy of the optimal shape is retained when the solution is updated. In addition, structures produced by AM need holes so that internal metal powder can be removed. Hence, we defined the design domain so that the optimal structure becomes open cell structure. Then, high bulk modulus shapes were derived using topology optimization. The lattice structures were produced by metal AM machine after being modified for production.

著者

河内 毅 栗山 幸久 鈴木 克幸

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.855, pp.17-00334-17-00334, 2017 (Released:2017-11-25)

参考文献数

15

被引用文献数

1

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In order to clarify the mechanism of the vehicle body hysteresis affecting “rigidity feeling”, one of the driver's sensory evaluation in the driving test, the influence of friction acting on spot welding flanges on hysteresis, which is drawn by displacement - load diagram under static or relatively slow deformation of double-hat-shaped parts assembled by spot welding, is experimentally evaluated. By measuring the difference between loss energy of a specimen with strong contact on welding flanges and that of another specimen without contact, friction loss (energy dissipation generated only by friction excluding inevitable loss energy for measurement possessed by testing system itself) is calculated. The friction loss rising with increasing load amplitude and load rate confirms that friction hysteresis occurs in the structure even under the elastic deformation. In this paper, the load rate dependence and the extrapolation point to the zero load rate are evaluated as the dynamic and static characteristics of friction loss, respectively. As a result, the dynamic characteristic obtains a result proportional to the load amplitude, and the static characteristic is proportional to the square of the load amplitude. Additionally, a model with the reaction force as the sum of linear elastic resistance due to bending and shear deformation, Coulomb friction proportional to amplitude of displacement and viscous friction is proposed. Using this model, the prediction of static and dynamic characteristic of the friction loss shows good agreement with results of the experiment. Finally, the friction-induced hysteresis led from the model is quantitatively discussed.

著者

土田 崇弘 上原 大暉 木村 康治

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.855, pp.17-00318-17-00318, 2017 (Released:2017-11-25)

参考文献数

7

被引用文献数

1

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Response distribution of a SDOF linear system subjected to non-Gaussian random excitation is investigated. The excitation is modeled by a zero-mean stationary stochastic process prescribed by the non-Gaussian probability density and the power spectrum with bandwidth and dominant frequency parameters. In this paper, we use bimodal and Laplace distributions for the non-Gaussian distribution of the excitation. The excitation is generated numerically by using the Ito stochastic differential equation. Monte Carlo simulations are carried out to obtain the stationary probability densities^ of the system displacement and velocity. It is found that the shape of the response distribution changes depending on a difference in the shape of power spectral density between the excitation and the response. In order to evaluate the difference of the spectral densities quantitatively, a new index is defined. The correspondence of this index to the shape of the response distribution is shown. Next, we compare the present difference index of power spectra and another index which the authors used in the previous study to investigate the response distribution of a non-Gaussian randomly excited system. The comparison shows that when the present index is close to 0, the shape of the response distribution looks like the shape of the excitation distribution. For the index around 0.6, the response distribution becomes the middle shape between the excitation probability density and a Gaussian distribution. In the case of the index greater than 1.2, the response distribution is nearly Gaussian. The difference index of power spectra between the excitation and the response can be calculated readily from the frequency response function of a linear system and the excitation power spectrum, regardless of the excitation probability density function. This index enables us to roughly estimate the shapes of the probability distributions of the displacement and velocity responses without Monte Carlo simulation.

著者

永代 行日出 細谷 浩之 中野 貴裕

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.855, pp.17-00310-17-00310, 2017 (Released:2017-11-25)

参考文献数

23

被引用文献数

1

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Acoustic metamaterial can have arbitrary acoustic characteristics , and there is possibility to improve acoustic performance of any products dramatically. As metamaterial, many kind of types have been propounded and studied. It is mainly classified into resonance type and non-resonance type.Resonance type metamaterial can change acousic characteristics drastically, but frequency range is narrow. Non-resonance type’s acoustic characteristics range is less than resonance type, but it can be changed in broad frequency band. It is a great advantage to use. About non-resonance type metamaterial, it has been already studied to control transmitted sound, but it has not been studied about reflection sound. If reflection sound control become possible, effective method can be chosen to solve noise problem. For example, resonance frequency in a duct will be shifted by changing reflection direction from the wall. In this study, the design method of non-resonance type metamaterial to control reflection sound has been studied by using FEM and Transfer-function method, and to verify the design method, element test was conducted. Element test result correspond well with analysis result, and the design method of acoustic metamaterial has been verified in this study. In order to put into practical use, further study with actual product shape is needed to confirm manufacturability.

著者

原 進 三島 直子 桑村 航矢

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.855, pp.17-00303-17-00303, 2017 (Released:2017-11-25)

参考文献数

10

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Horizontal moving body settling control mechanism which is mainly realized by momentum exchange, can be expected to save time of article transportation. Momentum exchange impact damper (MEID) is one of the mechanisms in order to solve shock response control problems. This paper proposes a novel hybrid mechanism consisting of passive MEID (PMEID) deceleration and active MEID (AMEID) rebound suppression for realizing rebound reduction of horizontal moving body colliding with a wall. In this method, all of the dampers are not released to the outside of the horizontal moving body but captured by soft springs to assume the actual usage condition. For the same reasons, the function to reduce the rebound and to extend the time in the state of zero rebound velocity is especially focused. The effectiveness of the proposed method is discussed by simulations and experiments. Simulations are conducted with both ideal and experimental conditions. Compared with the system with AMEID or PMEID only, the proposed hybrid MEID combines the advantages of each system and can realize settling control efficiently without releasing dampers out of the horizontal moving body. Ideal simulation results show that it is possible to reduce the rebound and the acceleration of moving body at the time of the collision, and reduce the active control input, simultaneously. These two advantages of the proposed method are also shown by the simulations with experimental conditions and the experimental results.

著者

岡本 峰基 田川 泰敬

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.855, pp.17-00277-17-00277, 2017 (Released:2017-11-25)

参考文献数

13

被引用文献数

1

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Vibration testing using a shaking table is a useful method to examine the vibration characteristics such as aseismic capacity of buildings for earthquakes and ride comfort of vehicles for vertical vibration. However, it’s necessary to design a controller which can reproduce the vibration such as earthquake waves accurately. Moreover, since there are various types of earthquakes such as a long-period earthquake and short-period earthquake, a controller with good tracking performance on wide frequency range is required in order to reproduce earthquake waves. Generally, a displacement feedback controller is employed in a control of the shaking table. However, almost all earthquake waves are saved as acceleration data. Therefore, an acceleration feedback controller is more proper to control the shaking table. The purpose of this study is to design an acceleration feedback control system with good tracking performance until high frequency range. However, it generates spillover caused by dynamics that is not included in plant model. As a result, the tracking performance of the controller degrades. So, we also proposed the method which can suppress spillover to solve this problem. The controller is designed based on Dual Model Matching method. Then, effectiveness of proposed control system is validated by experiments using 3degree-of-freedom shaking table.

著者

野田 幸矢 高山 俊男 小俣 透

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.855, pp.17-00253-17-00253, 2017 (Released:2017-11-25)

参考文献数

12

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In minimally invasive surgery robots, force sensing is required to improve its manipulability. To perform delicate surgery, three-axis force sensing is desired. However, in general, the force resolution in the axial direction is worse than that in the radial direction owning to a slender shape of a forceps. This paper proposes a double diaphragm structure for forceps flexural elements. The distance between the two diaphragms can adjust the rigidity in the radial direction without changing the rigidity in the axial direction when the thickness of the diaphragm is constant. Thus, the thickness of the diaphragm adjusts the rigidity in the axial direction, while the distance between the two diaphragms adjusts the rigidity in the radial direction. A planar spiral cutting in the cross section of the diaphragm can reduce the maximum stress applied on it. Moreover, by adjusting the two spiral phases and direction, the crosstalk of the radial and axial forces can be reduced. In 5 mm forceps simulation, the rigidity of the axial direction is almost equal to that of the radial direction when the distance between the two diaphragms is 6.0 mm. We performed experiments of 10 mm forceps model and confirmed that the resolution of the radial direction is almost equal to that of the axial direction when the distance between the two diaphragms is 12.0 mm.

著者

森 博輝 長嶺 拓夫 堀崎 大 佐藤 勇一

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.855, pp.17-00241-17-00241, 2017 (Released:2017-11-25)

参考文献数

8

被引用文献数

1

---

A long flexible shaft such as a lance tube in a soot blower or a drill string in a rotary drilling system exhibits friction-induced vibration resulting in a whirling motion. This paper investigates the whirling motion of a long flexible shaft induced by frictional force and examines the effect of an intermediate support position on the whirling motion. The experimental apparatus investigated has a vertical shaft which rotates at a constant speed by means of an electric motor mounted at the top of the shaft. At the bottom end of the shaft is located a rubber ring so that frictional force acts on the tip of the shaft when the shaft is deflected. Comparing experimental and calculated results we clarify the vibration characteristics, such as whirling frequencies and amplitudes, at various rotational speeds and show the effective position of an intermediate support to suppress shaft vibration.