Y. Kakinuma

Keio University, Edo, Tōkyō, Japan

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Publications (52)26.5 Total impact

  • R. Koike, Y. Kakinuma, T. Aoyama
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    ABSTRACT: Tool fracture detection is important to avoid tool breakage and ensure cutting accuracy. However, conventional tool condition monitoring methods use additional sensors that are expensive, increase the failure rate, and reduce the machine-tool stiffness. This study proposes a novel in-process method to detect tool fracture based on disturbance observer theory. It uses only servo information in a ballscrew-driven stage control system. Furthermore, a rotational digital filter is developed and applied to drilling tests to enhance the detection accuracy. Tool fracture is successfully detected without any external sensors by the proposed method.
    CIRP Journal of Manufacturing Science and Technology 01/2014; 7(3):177–184.
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    ABSTRACT: Disturbance observation is a sensorless process monitoring technique that has not yet been applied to the monitoring of tool collision in the use of machine tools. This paper presents a monitoring algorithm that detects collisions that involve the breakage of drills through observation of the disturbance force change rate. A comprehensive experimental study of diverse operator-induced collisions was conducted to analyze the collision detection potential of the disturbance observer. It was found that collision monitoring by the disturbance observer is more sensitive and responsive than that using a sensorless jerk observer.
    CIRP Journal of Manufacturing Science and Technology 01/2014;
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    ABSTRACT: The suppression of chatter vibration is required to enhance the machined surface quality and to increase tool life. In this study, a new, conceptually active approach for chatter suppression in machining is proposed. The hybrid control method developed by applying sensorless force control with a disturbance observer enables the simultaneous and independent control of the position trajectory and band-limited forces. The proposed method is introduced to the carriage of a prototype desktop-sized turning machine, and the ability to suppress chatter is evaluated by end-face cutting tests. The results demonstrate that actively controlling a band-limited force leads to the avoidance of chatter.
    CIRP Annals - Manufacturing Technology 01/2014; · 2.25 Impact Factor
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    ABSTRACT: To achieve maximally efficient signal processing, an electrical signal processing circuit needs to be replaced withan optical one. Optical micro-resonators, storing light at certain spots, areessential for optical signal processing. Single-crystal Calcium Fluoride (CaF2) is the most suitable materialfor highly efficient optical micro-resonators, and a resonator made of CaF2can be manufactured by ultra-precision machining. However, the performance of such optical micro-resonators depends on its surface integrity. In this study,therelation between the crystal anisotropy and surface integrity after ultra-precision cutting was investigated. The most difficult point in the cylindrical turning of a crystalline material is thatthe crystalline plane and the cutting direction constantly vary. We analyzed crack initiation and surface integrity of the entiremachined surface from the perspective of slip system and cleavage. Subsurface damage was also observed by using the TEM and X-ray analyzersfor more efficient manufacturing of optical micro-resonators.
    Procedia CIRP. 01/2014; 13:225–229.
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    ABSTRACT: This investigation reports the physical characteristics of electrorheological (ER) gels, which are a type of functional material having controlled surface friction. We previously developed slip clutches using ER gels sandwiched between electrodes, and verified their responses and controllability. We newly report the temperature and shear rate characteristics of ER gel in this study because the input and output electrodes of the clutch continuously slip past each other. While the temperature of ER gels increased when energized, the shear stress hardly changed. Instead, wearing and adaptation to the electrode affect the property. The shear rate hardly affected the shear stress in the high-shear-rate region. Conversely, the shear stress depended on the shear rate in the lower region.
    Journal of Physics Conference Series 01/2013; 412:012013.
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    ABSTRACT: With the development of virtual reality (VR) technology, many applications require force display systems. However, existing products are not widely used owing to their inconvenient fit and the possibility that the devices may inflict injuries on the user. This study aims to develop a VR suit that can display a force to each joint. The force is generated by a functional material, electrorheological (ER) gel. In this paper, we discuss the development of a device that attaches to the arm, and evaluate the usefulness of the ER gel wearable brake.
    2013 IEEE International Conference on Mechatronics and Automation, Takamatsu, Japan; 01/2013
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    ABSTRACT: The three-dimensional CO2 dissolution process through a gas–liquid interface in microfluidic devices was investigated experimentally, for the precise control of CO2 dissolution. The gas dissolution was evaluated by using confocal micron-resolution particle image velocimetry (micro-PIV) combined with laser induced fluorescence (LIF), which has the ability to measure the velocity and dissolved CO2 concentration distribution in a liquid flow field. The measurement system is based on the confocal microscope, which has excellent depth resolution and enables visualization of the three-dimensional distributions of velocity and dissolved CO2 concentration by rendering two-dimensional data. The device is comprised of a polydimethylsiloxane chip, whose microchannels were fabricated by using a cryogenic micromachining system. The width and depth of the liquid flow channel are larger than those of the gas flow channel. This is due to the need for decreasing the width of the gas–liquid interface and increasing the hydraulic diameter of the liquid channel, whose conditions generate a static gas–liquid interface. The experiments were performed for three different liquid flow conditions corresponding to Reynolds numbers of 1.0 × 10−2, 1.2 × 10−2 and 1.7 × 10−2, and the gas flow rate was set to be constant at 150 μL/min. The LIF measurements indicate that an increase in the Reynolds number yields a decrease in dissolved gas in the spanwise directions. Furthermore, molar fluxes by convection and diffusion were evaluated from the experimental data. The molar fluxes in the streamwise direction were at least 20 times as large as those in the spanwise and depthwise directions. This reveals that an increase in momentum transport in the spanwise and depthwise directions is an important factor for enhancing mass transfer in the gas–liquid microchannel flow.
    International Journal of Heat and Mass Transfer 05/2012; 55(s 11–12):2872–2878. · 2.52 Impact Factor
  • S.saito, Y.kakinuma, T.aoyama, K.tanaka, H.anzai
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    ABSTRACT: Electro-rheological Fluid (ERF) is the functional fluid that can change its viscoelastic property by applying electric field. However, ERF shows the sedimentation of the ER particles in long time use, and it caused the unstable ER effect. The Gel-structured ERF (ERG) has been developed to solve this problem. When a metallic flat plate is placed on the ERG sheet, ERG shows the high shear force due to the occurrence of the contact between the gel and the plate in response to the applying electric field (ERG effect). ERG effect can be obtained not only for metallic materials but also non-metallic materials by applying the one-sided electrode, and the ER effect is supposed to be considerably influenced by the material and geometrical properties of flat plate on the ERG sheet. In this study, the influences of the material and geometrical properties of sliding plate are experimentally analyzed from the viewpoint of the relative permittivity, surface roughness and flatness, and the design instruction for the selection of materials and their geometrical issues are proposed.
    International Journal of Modern Physics B 01/2012; 21(28n29). · 0.46 Impact Factor
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    ABSTRACT: The evaluation technique of gas permeable characterization has been developed for an increased efficiency of gas–liquid chemical reactions and high accuracy of environmental diagnosis. This technique enables us to measure spatial distributions of velocity and dissolved gas concentration by utilizing confocal micron-resolution particle image velocimetry combined with a laser-induced fluorescence technique. Microfluidic devices with gas permeability through polymer membranes are composed of a cover glass and a polydimethylsiloxane (PDMS) chip with the ability to permeate various gases, since PDMS is an elastomeric material. In the chip, microchannels are manufactured using a cryogenic micromachining system. The gas permeation is dominated by several factors, such as the gas and liquid flow rates, the membrane thickness between the gas and liquid flow, and the surface area of the membranes. The advantage of the present device is to realize the control of gas permeability by changing the surface roughness of PDMS, because the cryogenic micromachining enables us to control the surface roughness of microchannels and an increase in roughness yields an increase in the surface area of membranes. The experiments were performed under several conditions with a change in the gas flow rate, the PDMS membrane thickness and the surface roughness, which affect the gas permeation phenomena. The spatial distributions of velocity and dissolved gas concentration were measured in the liquid flow fields. The results indicate that the velocity-vector distributions have similar patterns under all experimental conditions, while the dissolved gas concentration distributions have different patterns. It was observed that the gas permeability through PDMS membranes increased with an increase in gas flow rates and surface roughness and with a decrease in membrane thicknesses, which is in qualitative agreement with membrane theory. The important conclusion is that the proposed technique is suggested to have the possibility of evaluating the characterization of gas permeable microfluidic device through membranes.
    Journal of Micromechanics and Microengineering 01/2012; 22(6). · 1.79 Impact Factor
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    ABSTRACT: This study is concerned with the development of an Electro-Rheological (ER) Gel Linear Actuator (ERGLA) as the principle component of a high torque controllable clutch that has applications in robots that coexist with humans. Applying the ER gel to clutches in force transmission assembly decreases the inertia and mechanical limit of the maximum speed, enabling keeping high controllability. This paper focuses on enlarging the output torque of the clutch with ER gels, which is a the main part of the ERGLA.
    Mechatronics and Automation (ICMA), 2012 International Conference on; 01/2012
  • Satoshi Ikeda, Yasuhiro Kakinuma
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    ABSTRACT: Plastics are regarded as proper materials for microfluidic chips, and, in particular, biodegradable plastics will be more appropriate from the viewpoint of environmental friendliness. In addition, when they are utilized as chip substrate, biochemical machining can be applied. Biochemical machining is a process, which utilizes enzymatic biodegradation. This paper describes studies on application of biochemical machining to nanofabrication of poly(l-lactic acid) (PLLA), which is one of the most widely used biodegradable plastics industrially. The degradation performance of enzyme (proteinase K) was experimentally evaluated to extrapolate a suitable condition for nanofabrication. Additionally, in order to make arbitrary channels with nano-order depth on PLLA, mask fabrication was proposed. It is a fabrication method to control degraded regions and obtain desired shapes with a mask, which has penetrating grooves. Using this method, we achieved fabrication of straight grooves with nano-scale depth. In conclusion, it is clear that biochemical machining can realize an effective process of arbitrarily shaped nanogrooves on PLLA.
    Precision Engineering-journal of The International Societies for Precision Engineering and Nanotechnology - PRECIS ENG. 01/2011; 35(3):440-446.
  • Yasuhiro Kakinuma, Yui Sudo, Tojiro Aoyama
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    ABSTRACT: Suppression of chatter vibration is required to improve the machined surface quality and enhance tool life. For monitoring the chatter vibrations, additional sensors such as acceleration sensors are generally used, which results in high costs and low reliability of the machine tools. In this study, a novel in-process method to detect chatter vibrations in end milling is developed on the basis of a disturbance observer theory. The developed system does not require any external sensors because it uses only the servo information of the spindle control system. Self-excited and forced chatter vibrations are successfully detected.
    Cirp Annals-manufacturing Technology - CIRP ANN-MANUF TECHNOL. 01/2011; 60(1):109-112.
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    ABSTRACT: ER gel exhibits various adhesive characteristics according to the applied electric field. This characteristic is called the EA effect. The results of a recent study reveal that the EA effect also occurs in a vacuum. Therefore, it is expected that ER gel can be applied to a chucking or damping device in a vacuum process. However, the characteristics of ER gel in a vacuum have not been sufficiently clarified. The purpose of this study is to experimentally evaluate the characteristic of ER gel in a vacuum. The performance of an ERG fixture element used for a silicon wafer in a vacuum is evaluated through shearing tests. The experimental results indicate that the ER gel demonstrates satisfactory performance in a vacuum. Moreover, the outgas released from the ER gel in a vacuum is evaluated, and the influence of the degassing time on the outgas is investigated.
    Journal of Intelligent Material Systems and Structures 01/2011; 22(15):1699-1705. · 1.52 Impact Factor
  • Y. Urakami, T. Aoyama, H. Anzai, Y. Kakinuma
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    ABSTRACT: Nowadays, due to the widespread use of rehabilitation and virtual reality technology, tactile display systems have attracted the attention of researchers from the medical and amusement fields. A clutch mechanism that employs ER and MR fluids is appropriate for force transmission in a tactile display device, because the ER and MR effects are passive and safe for the operator compared with an active actuator using motor. The developed ERG produces approximately 20 times higher shear forces than ER fluid and exhibits stable performance. In this research, an ERG multiple-disk clutch is fabricated and applied to a tactile display system. The experimental results of the control test indicate that the tactile display system with the proposed control method can exhibit the ‘sense of touch’ of various viscous fluids.
    Journal of Intelligent Material Systems and Structures 01/2011; 22(15):1693-1698. · 1.52 Impact Factor
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    ABSTRACT: ER gel is a relatively new type of functional material. The surface of ER gel has a shear stress characteristic, which increases according to the applied electric field. Introducing the gel into interface elements of a force transmission system realizes functional clutches and brakes. This study aims to develop a linear actuator that is safe, can operate in reverse, and can generate a large force using such a functional clutch. Applying an ER gel clutch in a force transmission system decreases inertia and the mechanical limits of the maximum speed while not limiting controllability. Such properties contribute to a high level of safety. This article reports, in particular, on stabilizing the output of the linear actuator.
    Journal of Intelligent Material Systems and Structures 01/2011; 22(15):1685-1692. · 1.52 Impact Factor
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    ABSTRACT: Current research includes applying new functional materials to mechatronic devices and Electro-Rheological (ER) gel is one of these new functional materials. ER gel enables the development of mechatronic devices which have both high speed response and high levels of safety. In particular, the requirements for power assist devices are high speed response, high safety, and backdrivability. The purpose of this study is to develop an ER gel belt transmission system for use in power assist systems. We applied an ER gel in the power transmission role of a belt transmission system. When the ER gel of this system is de-energized, the input torque is not transferred because of minimal shear stress. When the ER gel is energized by an electric field, the increased shear stress results in a torque transfer. The ER gel belt transmission system functions as a clutch with controlling torque based on these characteristics of the ER gel. The paper proposes such an ER gel belt transmission system, describes it's design and operational features, and presents the results of basic performance experiments.
    SICE Annual Conference (SICE), 2011 Proceedings of; 01/2011
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    ABSTRACT: We aim to create a novel prototype linear actuator with new structure applying an ER (Electro-Rheological) gel, a recent functional material. The actuator will be an all-purpose actuator satisfying characteristics for human-coexistence application. Such actuators for the application need large generative force, high speed response, good controllability, high safety, low friction, backdriveability and so on. We have put emphasis on the backdriveability and safety. The actuator developed by us will contribute to create robots manipulated by human recently aggressively researched.
    Intelligent Robots and Systems (IROS), 2010 IEEE/RSJ International Conference on; 11/2010
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    Daisuke Kurihara, Yasuhiro Kakinuma, Seiichiro Katsura
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    ABSTRACT: Intelligent machine tools require the functions of high-accurate process monitoring and adaptive control to fit the optimum process condition in each workpieces. For realizing these functions, the various techniques to monitor the cutting process and control it using additional sensors have been proposed and widely studied. Authors propose the sensorless cutting force control method using parallel disturbance observer. The performance of our proposed method is evaluated through simulation and experiments using a linear motor driving table.
    Journal of Advanced Mechanical Design Systems and Manufacturing 01/2010; 4:955-965. · 0.49 Impact Factor
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    ABSTRACT: Robots manipulated by humans are being aggressively researched and developed. Such robots have requirements such as a large generative force, high-speed response, good controllability, high safety, low friction and backdriveability. We focused on backdriveability and created a prototype for a novel linear actuator with a new structure that includes an electrorheological (ER) gel, which is a recently designed functional material. The device is an all-purpose actuator that satisfies the demands for application in a human-coexistence welfare robot, such as power-assist systems. This paper presents the original plan for the linear actuator, shows the actuator as currently manufactured and presents the basic characteristics of the actuator as investigated experimentally. We obtained larger force from the linear actuator than the initial target. Additionally, the linear actuator shows possibilities of further improvement of the force–weight ratio by an increase of the ER gel structures. With regard to stabilizing the response of the linear actuator, spring elements contributed to its improvement. However, further stabilization remains as a future issue for practical use in human-coexistence robots.
    Advanced Robotics 01/2010; 24:1963-1981. · 0.51 Impact Factor
  • Y. Kakinuma, T. Aoyama, H. Anzai
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    ABSTRACT: Electrorheological gel (ERG) is a novel functional elastomer, which has frictional and adhesive surface properties that vary according to the intensity of an applied electric field. This peculiar phenomenon is referred to as the electro-adhesive (EA) effect. The shear stress of ERG generated under an applied electric field is approximately 30-40 times higher than that of electrorheological fluids (ERF), due to its high adhesive strength. However, the generated EA effect of ERGs varies widely due to surface conditions, especially the density and distribution of ER particles at the surface. In order to stabilize and improve the performance of ERG, the electrical field-assisted molding process is proposed as a production method. In this process, the mixture solution including ERFs and gel agent is gelling under electric field. The principle of the EA effect is theoretically investigated and a high-performance ERG produced by the proposed process, in which ER particles are aligned densely at the surface, is developed and the performance is experimentally evaluated by surface observation and shear test, revealing a highly dense arrangement of ER particle at its surface and a higher shear stress twice that of conventional ERG.
    Journal of Intelligent Material Systems and Structures 01/2010; 21(15):1501-1508. · 1.52 Impact Factor