TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series C
Online ISSN : 1884-8354
ISSN-L : 1884-8354
Volume 77, Issue 782
Displaying 1-39 of 39 articles from this issue
Special Issue on "The Norms of Manufacturing and Machine Tools 2010"
Preface
Review
Regular Paper
  • Haruhisa SAKAMOTO, Shuichiro TAGUCHI, Shinji SHIMIZU
    2011 Volume 77 Issue 782 Pages 3552-3561
    Published: 2011
    Released on J-STAGE: October 25, 2011
    JOURNAL FREE ACCESS
    During milling process, the cutting force acts on tool end like cantilever bending, consequently, the deflection of cutting point cannot be avoided. In order to specify the deflection accurately, it is necessary to determine the bending stiffness characteristics of milling chucks. In this paper, the evaluation method of the bending stiffness characteristics is proposed concretely, and then, the characteristics of typical milling chucks are examined experimentally. The tool chucking region can be modeled mechanically as the equivalent spring distribution in the tool hole on milling chucks. Based on this model, the bending stiffness characteristics can be quantified with two parameters, such as the equivalent start depth l0 of chucking force from the entrance of tool hole, and the equivalent spring coefficient k per chucking length. From the application results of the proposed evaluation method for typical chucks, the following are found out: the changes in these parameters depend upon the structure of tool chucking mechanism. Moreover, the bending stiffness of overall tooling including tool is influenced by not only chuck but also tool condition such as material property and chucking condition. Especially, the higher the tool stiffness is, the more remarkable the influence of the bending stiffness characteristics of chucks is.
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  • Masahiko SATO, Hisataka TANAKA, Satoshi TAKEDA
    2011 Volume 77 Issue 782 Pages 3562-3571
    Published: 2011
    Released on J-STAGE: October 25, 2011
    JOURNAL FREE ACCESS
    In drilling, excessive temperature rise is known to cause various types of thermal damage to the drill and workpiece. This paper presents a novel approach to measure the temperature variation on the machined surface at the bottom of the hole during drilling. A newly developed infrared radiation pyrometer equipped with two optical fibers is used to measure the temperature. One of the optical fibers is inserted through the oil hole of internal coolant carbide drill. It runs through the inside of the machine tool spindle and connects to the other optical fiber at the end of the spindle. Infrared rays radiating from the bottom of the hole during drilling are accepted and transmitted to the pyrometer by the two optical fibers. The workpiece thickness, spindle speed and feed rate are varied as experimental conditions. The temperature increases gradually as drilling progress and increases rapidly near the undersurface of the workpiece, possibly due to the reduced capacity of the workpiece to conduct heat away from the drill point. The temperature rise near the bottom of the workpiece effects on the rapid drill wear.
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  • Motochika SHIMIZU, Hiroshi SAWANO, Hayato YOSHIOKA, Hidenori SHINNO
    2011 Volume 77 Issue 782 Pages 3572-3580
    Published: 2011
    Released on J-STAGE: October 25, 2011
    JOURNAL FREE ACCESS
    Vibration isolation has been widely used for precision machining systems to reduce vibration errors caused by disturbance. In general, vibration isolation units have mechanical contact points between a base and a table, while ground vibration passes through these contact points. This paper presents a newly developed non-contact type active vibration isolation unit which consists of an air spring, a voice coil motor, and an aerostatic bearing. The developed unit also has an active vibration control function to reduce an influence of direct disturbance force. Vibration isolation experiments confirm that the resonances in ground vibration transmission and direct disturbance transmission can be reduced and the influence of ground vibration can be decreased.
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  • Masaki IZAWA, Kiminobu MIYANO, Naoki ASAKAWA
    2011 Volume 77 Issue 782 Pages 3581-3588
    Published: 2011
    Released on J-STAGE: October 25, 2011
    JOURNAL FREE ACCESS
    This study deals with polishing using abrasive water jet for corner parts of a mold. In recent years, great varieties of small volume production progresses and the demand for metal molds and dies is increasing. However, automation of polishing process is under developing, and expert workers manually perform polishing work which takes much time and requires skills. This study aims at rationalizing such difficult polishing work by application of abrasive water jet which uses free abrasive grains. In previous research, the surface roughness of 0.058μm(Ra) was achieved on polishing for plane surface of mold material. Since the nozzle was paralleled to finished surface and had collision with workpiece, it was difficult to apply abrasive water jet to polishing mold . In this report, round groove shaped workpieces, which are seen at corner parts of a mold, are dealt as one of difficult parts for manually polishing. The experiment on incident angle from workpiece is performed to cope with collision avoidance between mold and nozzle. From the experimental result, we discuss relation between incident angle and abrasive energy giving affect to erosion on polishing surface using abrasive water jet.
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  • Shinji SHIMIZU, Takayoshi YAMASHITA, Haruhisa SAKAMOTO
    2011 Volume 77 Issue 782 Pages 3589-3596
    Published: 2011
    Released on J-STAGE: October 25, 2011
    JOURNAL FREE ACCESS
    Cylindrical grinding machines are typical machine tools for the final finishing process which produce high accurate and value-added products. However the universal method of measurement and evaluation for their thermal displacement has not been established. Therefore, in this study, we propose a measurement and evaluation method for the thermal displacement of the cylindrical grinding machines with rotation of the wheel spindle and make a device on an experimental basis based on the proposition and examine their validity. As the result of this study, it is made clear that the method proposed by us can measure and evaluate effectively and simultaneously 5 thermal displacements of the cylindrical grinding machines, that is, 3 translational deviations and 2 angular deviations.
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  • Sho AYADA, Hiroshi SAWANO, Hayato YOSHIOKA, Hidenori SHINNO
    2011 Volume 77 Issue 782 Pages 3597-3607
    Published: 2011
    Released on J-STAGE: October 25, 2011
    JOURNAL FREE ACCESS
    Demands for measuring three-dimensional (3D) micro-geometries over a large scanning range have recently increased in a various industries such as aerospace, dies and molds, energy, etc. This paper presents a newly developed 3D profile measuring system with both a large scanning range (18mm×18mm×10mm) and a nanometer resolution. The profile measuring system developed is consisted of an AFM probing system and a newly developed 3D nano-motion system with a large travel range. Elimination of motion errors in the nano-motion system enables the AFM probe to scan a specimen with a nanometer resolution. The measurement results of an optical lens confirmed that the developed system achieves high measurement accuracy over a large scanning range.
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Mechanical Systems
Regular Paper
  • Nobuyuki SOWA, Takahiro KONDOU
    2011 Volume 77 Issue 782 Pages 3608-3620
    Published: 2011
    Released on J-STAGE: October 25, 2011
    JOURNAL FREE ACCESS
    Pattern formation phenomena often occur in contact rotating systems. In a previous report, a countermeasure employing a dynamic absorber was suggested and optimized for a single-DOF system. When a similar design is applied to a multi-DOF system, some additional difficulties arise. Due to different natural modes, multiple dynamic absorbers are required. As a result, the calculation effort increases significantly due to the dramatic increase in the number of design parameters when all of the absorbers are designed simultaneously. Additionally, as the modes are somewhat interdependent, it is difficult to design appropriate dynamic absorbers for a multi-DOF. In order to overcome these difficulties, a systematic mode-by-mode design approach is proposed. Meanwhile, a criterion clarifying the relativity of unstable vibration modes before and after adding the dynamic absorbers is derived by using the stability analysis developed in earlier studies. The effectiveness of the proposed method is then verified with results calculated numerically from an example 5-DOF system.
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  • Takaaki NAGASHIMA, Taichi SATO, Kihachiro TANAKA
    2011 Volume 77 Issue 782 Pages 3621-3636
    Published: 2011
    Released on J-STAGE: October 25, 2011
    JOURNAL FREE ACCESS
    We applied the impact damper system to the vibration model of a cantilever beam. The impact damper system consists of an impactor and walls placed in a container, which vibrates in the horizontal and vertical directions when the first and second modes of vibration are excited at the same time. The damping effects are influenced by a clearance between an inpactor and walls of a container. We changed the clearance and the acceleration of the foundation and investigated the damping characteristics of the impact damper system when the system vibrated in two directions at the same time. We calculated the vibration response of the impact damper numerically, and found that the calculation results were in accordance with the experimental ones. The impact damper system converts the vibration energy of the vibrating body to the kinetic energy of the impactor by collision. Therefore, to investigate the damping effects of two directions in the simultaneous vibration, we calculated the mechanical energy of the vibration system. We found that the damping effects of the horizontal direction were not affected by the vertical vibration when a horizontal clearance was larger than the optimum clearance. On the other hand, we found that the damping effects of vertical direction were not affected by the horizontal vibration when the impactor did not collide to the ceiling. In other words, we found that using an impactor reduced the vibrations of both the horizontal and the vertical direction at the same time when the clearance was properly adjusted.
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  • Hiroki MORI, Takuo NAGAMINE, Tsubasa KOYAMA, Yuichi SATO
    2011 Volume 77 Issue 782 Pages 3637-3647
    Published: 2011
    Released on J-STAGE: October 25, 2011
    JOURNAL FREE ACCESS
    There are some mechanical systems that involve impacts, e.g. vibratory feeders, impact dampers, vibrating screens and so on. Sometimes unwanted low frequency vibration occurs in such vibroimpact systems. This paper regards such vibration as self-excited vibration generated in vibroimpact systems. Experimental and calculated results show that the self-excited vibration occurs in the parameter range where unstable periodic solutions exist. Further numerical simulations demonstrate that distance between a bouncing mass and a main system has an exciting or damping effect on the center of gravity of the system.
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  • Takuo NAGAMINE, Hiroki MORI, Tomoyuki MOTEGI, Yuichi SATO
    2011 Volume 77 Issue 782 Pages 3648-3657
    Published: 2011
    Released on J-STAGE: October 25, 2011
    JOURNAL FREE ACCESS
    A large-scale unexpected vibration is caused by pedestrians walking on a footbridge. We model a bridge and walking as a suspended platform and oscillation. In this study, we describe experimental results and numerical simulations of the horizontal vibration of a platform suspended by strings. The platform is excited by five oscillators in the experiment. The platform begins to vibrate considerably when synchronized phenomena of the oscillators occur. We investigate the effects of the damping and the natural frequency of the platform on the mode of vibration and the conditions of the existence of synchronized phenomena. On the basis of the results, the conditions of small vibration of the platform and effects of the number of oscillators on the large vibration are clarified.
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  • Yasuyuki SUZUKI, Yoshihito KAGAWA
    2011 Volume 77 Issue 782 Pages 3658-3671
    Published: 2011
    Released on J-STAGE: October 25, 2011
    JOURNAL FREE ACCESS
    To eliminate vibration of a flexible cantilever beam, straight SMA wires are used as tendons and are actively controlled. Actuators consist of SMA connected to a spring that is fixed at the end and are obliquely connected to the cantilever beam. The state equations of the mechanical system are formulated from decoupled vibration equation of the cantilever beam on the mode coordinate applying linearized force of the SMA-spring component about the equilibrium point by defining the state variables as modal displacement, velocity of the beam and force of the SMA-spring structure. Since the linearized model of the SMA-spring components includes varying parameter according to amplitude of applied voltage, gain scheduled H controller is designed for the system to obtain high control performance by using SMA under less hysteresis deformation. The simulations and experiments demonstrated that the four vibration modes (three bending and one torsional modes) of the cantilever beam could be simultaneously damped. Furthermore, it was verified that SMAs were stably controlled within less hysteresis deformation that supposed in modeling process.
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  • Yasuyuki YAMADA, Toshio MORITA
    2011 Volume 77 Issue 782 Pages 3672-3683
    Published: 2011
    Released on J-STAGE: October 25, 2011
    JOURNAL FREE ACCESS
    In this paper, we propose a passive gravity vector control mechanism, which named “Mechanical Gravity Generator (MGG).” From development and geometry calculation of a link model with the MGG, it is clarified that our device has three advantages described below in comparison with conventional passive gravity compensation mechanisms and other handling mechanisms. (1) In all directions, it allows the passive stabilization of the links by setting parameters of MGG. (2) MGG increases the payload than conventional passive gravity compensation mechanisms when the link position is under the equilibrium positions. (3) The equilibrium positions of serial links with MGG can be designed independently for each link. In conclusion, the novel device enabled to get high power and easy posture control by the effect of generated virtual gravity.
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  • Yukinori NAKAMURA, Kazuki MORIMOTO, Shinji WAKUI
    2011 Volume 77 Issue 782 Pages 3684-3693
    Published: 2011
    Released on J-STAGE: October 25, 2011
    JOURNAL FREE ACCESS
    This paper considers implementation of feedback error learning (FEL) for linear slider position control. The effect of modelling error of the slider is compensated by FEL. In algorithm of FEL, parameters of feedforward controller are updated so that output signals of a feedback controller can become small. It leads to improvement of tracking performance. On the other hand, when conventional FEL algorithm is implemented for control of a linear slider, parameters of the feedforward controller tend to converge slowly. In industrial scenes, it is desirable to shorten learning time in order to reduce cost of setting up manufacturing devices. Furthermore, when the learning time is long, guide rails of the slider become worn. It is shown that convergence speed is improved by tuning free parameters of the feedforward controller. Due to further improvement of the convergence, by using prefilter and free parameters of feedforward controller, some parameters of an inverse system are obtained a priori and utilized for learning. Command with mixed frequency is selected in order to identify accurate inverse system of plant. Simulation results are presented to show the effectiveness of proposed method.
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  • Takao NANJO, Etsujiro IMANISHI
    2011 Volume 77 Issue 782 Pages 3694-3704
    Published: 2011
    Released on J-STAGE: October 25, 2011
    JOURNAL FREE ACCESS
    The modeling for the total system of the hybrid excavator is presented by introducing the flexible multibody system with the electric-hydraulic drive system, which consists of the engine, the battery system, the generator, and actuators driven by the electric-hydraulic power train system. The attachment and the hydraulic system of the hybrid excavator are formulated by introducing the nonlinear finite element analysis. The power electronic system, which includes the battery system, the generator, the convertor, the motor, and the controller, is modeled by employing the analogy of the hydraulic circuits. Firstly, the dynamic simulations are performed by using this model in the boom system for the operability design. It is demonstrated that the vibration control is effective to reduce the residual vibration of the boom. Secondly, the dynamic simulations are carried out for the energy saving performances of the hybrid excavator, which are conducted on the actual operation such as the excavating, and so on. It is verified that the simulation results for both the power and the energy saving performance fairly agree with the experimental ones. The energy saving effects of the hybrid excavator can be expected to be more than 40% for the actual operation comparing with the conventional one.
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  • Yusuke KURISHIMA, Kenichiro NONAKA
    2011 Volume 77 Issue 782 Pages 3705-3720
    Published: 2011
    Released on J-STAGE: October 25, 2011
    JOURNAL FREE ACCESS
    In this paper, a novel robust sliding mode steering and driving force controller for front steering ground vehicles with coupled nonlinear dynamic model is presented. Unlike the conventional front steering vehicle controllers, the proposed controller deals with longitudinal, lateral, and yaw motion simultaneously, including coupling nonlinear dynamics between them while ensuring robustness against the uncertainty and external disturbances. Since these coupled dynamics are nonlinear and difficult to solve them analytically, we use an iterative method which is feasible at real-time computation. It is noted that this iterative computation includes the effect of sliding mode controller; the numerically computed control is robust against external disturbance or uncertainty which satisfies the matching condition. The efficacy and advantage of the proposed controller over a conventional method is verified through both simulation and experiment.
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  • Keigo FUJIMOTO, Makoto YOKOYAMA, Yuji TANABE
    2011 Volume 77 Issue 782 Pages 3721-3736
    Published: 2011
    Released on J-STAGE: October 25, 2011
    JOURNAL FREE ACCESS
    Focusing on uncertain aerodynamic coefficients which characterize the thrust and torques, an adaptive controller for a four-rotor mini helicopter is designed based on Immersion and Invariance (I&I) approach. In order to deal with the complex multivariable parameter estimation, a relatively simple model parameterized with respect to a few unknown parameters is developed. For the estimation of those parameters, the I&I approach is employed and the design parameters of the resulting estimator are easy to adjust. With the estimates of the parameters, several tracking controllers are designed based on the backstepping methodology. Numerical simulation illustrates the robustness of the controller against the parametric uncertainties and external disturbances.
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  • Toshiki MATSUI, Naoki SUGANUMA
    2011 Volume 77 Issue 782 Pages 3737-3749
    Published: 2011
    Released on J-STAGE: October 25, 2011
    JOURNAL FREE ACCESS
    Extraction of road region is a core technology for an autonomous vehicle which achieves safer transport. We propose extraction and modeling method for the road region in front of vehicle, using three-dimensional shape that is analyzed by stereovision. In order to model even if the extracted region has longitudinal slope, a continuous planar model is used. This method uses some structural features of road region. Therefore, it is usable even if the road has no traffic lanes. In this paper, we describe the planar approximation based on principal component analysis. Additionally, a technique of road region candidate selection using a coefficient of determination, and a modeling procedure based on characteristic of image sensor have been proposed. Finally, effectiveness of the method is demonstrated on experiments with various real environment scenes.
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  • Kazuhiro TSUBOI, Yasuaki KONAGAYA
    2011 Volume 77 Issue 782 Pages 3750-3760
    Published: 2011
    Released on J-STAGE: October 25, 2011
    JOURNAL FREE ACCESS
    We investigate the projection model with the effect of run-up that includes three variables: projection speed and angle, and also a horizontal speed at projection. These variables express the least effect for the multi-degree of freedom of a human body. In the model with three variables, a constraint between initial speed and initial angle is derived, and it presents the adequate function for projection with the run-up effect. We attempt to determine the function by comparing its shape with that of the given constraints in shot put and long jump. Consequently, the function derived from the model with three variables reproduces successfully the measured results, and estimated values of the model variables predict the optimum values of the initial speed and initial angle. This means that the model with three variables includes a constraint between initial speed and initial angle, and therefore we conclude that it provides theoretical ground for projection with the run-up effect in sports activities.
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  • Yoshitaka SHIRAISHI, Takeshi SHIMOTO, Hidehiko HIGAKI, Yoshitaka NAKAN ...
    2011 Volume 77 Issue 782 Pages 3761-3769
    Published: 2011
    Released on J-STAGE: October 25, 2011
    JOURNAL FREE ACCESS
    In biomechanics of the knee joints, the definition of the cruciate ligament adhesion areas is discussed for the cruciate ligament reconstruction. Effective information can be expected to be fed back to the cruciate ligament reconstruction if accurate movement of the natural knee joints can be analyzed. Therefore, this study performed in vivo six-degree-of-freedom (6-DOF) motion analysis for the natural knee joints with high precision using an image matching technique. The image matching technique was performed determining the strength of correlation between the X-ray images from a single-plane flat panel detector (FPD) and the computational simulated image from three-dimensional gray-scale model reconstructed using computed tomography (CT). Average root mean square errors of this technique were 0.84 mm for the in-plane translation, 0.17 mm for the out-of-plane translation, and 0.29 degrees for the rotation. We report analysis results for the natural knee joints in squat activity using this technique. Subjects were the natural knee joints of four healthy men. We assessed the four items for the motion pattern and the functionality of cruciate ligament. The roll-back motion of subluxation in high-flexion, and the importance of anteromedial (AM) bundle and posterolateral (PL) bundle in the anterior cruciate ligament (ACL) could be confirmed from the results. From these, this highly accurate technique can be expected to become a valuable tool for the medical device development and the diagnostic in field of orthopedics.
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  • Kouki DOI, Tsutomu WADA, Hiroshi FUJIMOTO
    2011 Volume 77 Issue 782 Pages 3770-3779
    Published: 2011
    Released on J-STAGE: October 25, 2011
    JOURNAL FREE ACCESS
    Recently, many tactile guide maps have been installed at various public facilities with the enactment of “Barrier Free New Law”. In tactile guide maps, some tactile symbols have been used for indicating some information items. Japanese Standards Association enacted Standardized Method of Displaying Tactile Guide Maps March 2007 (JIS T0922). Tactile symbols shapes are regulated by the JIS. However, other components of tactile symbol (such as edge, size etc) are unregulated because there are no sufficient research achievements regarding tactile symbols. In this study, for the purpose of investigating influence of tactile symbols edge clarity on their tactile symbols, we compared tactile symbols discriminability in two conditions with tactile symbol edge clarities (acute type (cutting method) and gentle type (screen printing method)). We made tactile symbol test pieces with various sizes by the two methods. And twelve older participants and twelve younger participants were asked to discriminate tactile symbol test pieces. From this study, we found the relation between tactile symbols edge clarity and discriminability of tactile symbols. It was also found that tactile symbols edge clarity influence on their discriminability when the size was particularly small.
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  • Jun OKAMOTO, Yu KUMASAKA, Kazuya KAWAMURA, Tomoyuki MATSUMOTO, Seiji K ...
    2011 Volume 77 Issue 782 Pages 3780-3793
    Published: 2011
    Released on J-STAGE: October 25, 2011
    JOURNAL FREE ACCESS
    We have been developing the Orthopaedic physical examination assisting system using magnetic position tracker to quantitate knee laxity diagnosis. In this study, to investigate the influence of anatomical landmark sampling error for bone coordinate registration, reproducibility verification simulation was done. Firstly, the motion data of imitation bones was acquired using the system and set as a reference data. To get the error motion data, virtual error vectors were added on the reference sampling points and new motion data was recomputed. Evaluation was executed by comparison with the reference data and recomputed data. The evaluation results lead improvement methods of measurement reproducibility as follows. 1. It is important to point the landmarks proximal to the knee carefully because the contribution of the motion error is higher than the distal landmarks. 2. To reduce the registration error, thigh and shank receivers should be set close to the knee as possible. 3. If the allowance area of the sampling error is in 2.0 mm diameter circle, Diagnosis error using IKDC Knee examination form is approximately 20 %.
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  • Toshiharu MUKAI, Shinya HIRANO, Hiromichi NAKASHIMA, Morio YOSHIDA, Sh ...
    2011 Volume 77 Issue 782 Pages 3794-3807
    Published: 2011
    Released on J-STAGE: October 25, 2011
    JOURNAL FREE ACCESS
    In aging societies, there is a strong demand for robotics to tackle problems resulting from the aging population. We have developed a prototype nursing-care assistant robot, RIBA, which was designed to come in direct contact with patients and conduct physically challenging tasks. RIBA interacts with its object, typically a human, through multiple and distributed contact regions on its arms and body. To obtain information on such whole-body contact, RIBA has tactile sensors on a wide area of its arms. The regions where hard contact with the manipulated person may occur have almost flat surfaces, leading to surface contact involving a finite area, in order to reduce contact pressure and not to cause the person's pain. When controlling the position and orientation of the person, the relative positions and orientations of the distributed contacting surfaces should be preserved as far as possible to maintain stable contact and not to graze the person's skin. Preserving the force and the pressure pattern of each contact region using tactile feedback is also important to provide stable and comfortable human-robot physical interaction. In this paper, we propose a whole-body contact manipulation method using tactile information to meet these requirements. Results of basic experiments are also shown.
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  • 2011 Volume 77 Issue 782 Pages 3808-3817
    Published: 2011
    Released on J-STAGE: October 25, 2011
    JOURNAL FREE ACCESS
Note
  • Takashi KAI, Masaya AKIYAMA, Shinji WAKUI
    2011 Volume 77 Issue 782 Pages 3818-3822
    Published: 2011
    Released on J-STAGE: October 25, 2011
    JOURNAL FREE ACCESS
    An absolute displacement sensor has been proposed for precise vibration control of semiconductor manufacturing equipments. Based on state feedback, a control model of the sensor is designed in order to obtain feedback gains as optimal regulator. However, frequency characteristics in simulations are different from those in experiments due to back electromotive force from a forcer coil. In this paper, a voltage-feedback-type driver of the sensor is replaced by a current-feedback-type driver in electric circuits. This is because the latter driver can ignore effects of the back electromotive force. Firstly, we express principles of the effects in equations. Next, the control model is modified, and simulation parameters are identified. As a result, the simulations are corresponding to the experiments.
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Machine Elements, Design and Manufacturing
Essay
Regular Paper
  • Yuji MURE, Masanobu UMEDA
    2011 Volume 77 Issue 782 Pages 3828-3839
    Published: 2011
    Released on J-STAGE: October 25, 2011
    JOURNAL FREE ACCESS
    In this research investigation, we have proposed a cold forging process planning reproduced the expert engineer's thinking process faithfully, and have also developed a practical knowledge-based system for axisymmetrical cold forged products. In this system, a forged product is represented as an aggregation of the forming patterns consisting of cylindrical pillar parts. The basic principle of the inference is the adjustment of the diameters of neighboring stepped cylinders so that they are all the same. Deformable process plans are generated by using expert knowledge regarding working limits and metal flow. The system can eliminate useless plans by using the knowledge of how to combine plural forming patterns in one process. Moreover, it can evaluate process plans by considering forming load, effective strain in the product and select an optimal one by using FEM simulation. We applied the system to actual forged products, and appropriate results were obtained including a practical process plan. The knowledge using the basic principle is widely applicable to various axisymmetrical forged product shapes.
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  • Toshimichi FUKUOKA, Masataka NOMURA, Takahiro KAMIHIRA
    2011 Volume 77 Issue 782 Pages 3840-3849
    Published: 2011
    Released on J-STAGE: October 25, 2011
    JOURNAL FREE ACCESS
    Tire coming-off accidents from large vehicles are primarily caused by the fatigue failure of wheel bolts, by which the tire wheels are clamped to the hubs of the shaft. In the previous study, stress amplitudes occurred in wheel bolts were measured using a full-scale test equipment, which was constructed utilizing an actual trailer. In the experiments, the thread ridges of the wheel bolts were partly removed and the portion was machined into cylindrical shape in order to attach strain gauges. To examine the fatigue mechanism in more detail, it is necessary to evaluate the stress amplitudes at thread root, where the fatigue failures of threaded fasteners usually occur. In this study, the stress amplitudes at thread root are analyzed using three-dimensional FEM. Threaded portions are modeled using fine meshes to evaluate the stress amplitudes generated in both wheel bolts and inner nuts with sufficient accuracy. The magnitudes of the live loads, which exert alternating external forces on the wheel bolted joints, are varied so as to cover from the normal condition to the over-loaded ones. It has been found that the maximum stress amplitudes at the threat root significantly increase when the initial clamping force decreases as low as 30% of the prescribed value, which is also exaggerated with larger friction coefficient at contact surfaces around wheel bolted joints. The validity of the numerical analysis is confirmed by comparing the numerical results of the stress amplitudes on the wheel bolt surface with those by experiments.
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  • Yosuke NAITO, Yusuke URAKAMI, Yasuhiro KAKINUMA, Tojiro AOYAMA, Hideno ...
    2011 Volume 77 Issue 782 Pages 3850-3860
    Published: 2011
    Released on J-STAGE: October 25, 2011
    JOURNAL FREE ACCESS
    Electro-rheological Gel (ERG) is a novel functional elastomer which changes its surface frictional and adhesive property according to the intensity of applied electrical field. This unique property is called Electro-adhesive (EA) effect. It is expected that ER gel is applied to various passive actuator devices such as brake systems and clutch systems, because adhesive property of ERG can be controlled according to the intensity of applied electrical flied. From past studies, we estimate that mechanism of EA effect is attributed to the adhesion of silicone gel and cohesion of ER particles of which ERG is composed. The influence of silicone gel and ER particle on electro adhesive phenomenon, however, has not been studied yet. In this study, relation between electro adhesive phenomenon and characteristics of ER particles is elucidated experimentally by changing the kind of particle and particle diameter. Moreover, relationship between electro adhesive effect and the hardness of silicone gel is analyzed by changing silicone oil into the various viscosities. As a result, it is confirmed that EA phenomenon is also generated using organic particles. Moreover, relationship between electro adhesive effect and the hardness of silicone gel is analyzed by using various viscosities of silicone oil. The result indicates that the EA effect phenomenon is also generated by using organic particles and the phenomenon is affected by the size of particles. In this case, the intensity of EA effect has proportionally increased by reducing the diameter of particles. Additionally, it is unveiled that silicone oil requires the optimum value of viscosity to produce the best performance of EA effect.
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  • Masakatsu KUROISHI, Atsushi KAWAGUCHI, Syuzou SANDA, Mizuho INAGAKI, N ...
    2011 Volume 77 Issue 782 Pages 3861-3870
    Published: 2011
    Released on J-STAGE: October 25, 2011
    JOURNAL FREE ACCESS
    In this study, we have developed a coupled analysis method of piston dynamics and lubrication. The kinematic motion and structural vibration are calculated by the flexible multibody dynamics theory developed in the former study. The mixed lubrication film between the piston skirt and the cylinder bore is numerically modeled as a force element. The hydrodynamic pressure and the friction force in fluid lubrication region on this interface are solved by a finite difference method. The contact pressure and the friction force by solid contact are calculated by the statistic asperity contact model. This mixed lubrication model is validated by a reciprocating friction tester. Then, we apply this method to the estimation of the friction force measured by a floating liner type friction tester at firing condition, and clarify the contributions of hydrodynamic and solid contact on the friction force.
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  • Jungchul KANG, Masaharu KOMORI, Fumi TAKEOKA, Yuji ONODERA
    2011 Volume 77 Issue 782 Pages 3871-3880
    Published: 2011
    Released on J-STAGE: October 25, 2011
    JOURNAL FREE ACCESS
    Ratio variable transmissions are used when a wide range of speed and torque is required for mechanical devices. Geared transmissions are applied for a wide variety of machines. However, power and motion transmission from the input shaft to the output shaft is interrupted during the ratio changing process in geared transmissions. In order to solve this problem, a novel ratio variable system has been proposed in the previous report. This system uses a noncircular gear that can realize the reduction ratios of two gear pairs and has accomplished the ratio change from the first ratio to the second ratio while transmitting power and motion. In this report, multi-speed ratio variable system to transmit power and motion continuously is proposed in which a noncircular gear with multi-speed ratio is incorporated. Geometrical form of the noncircular gear for this system is analyzed. The experimental apparatus is constructed and the experimental result shows that this ratio variable system can realize multi-speed ratio change while transmitting torque and rotation.
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  • Takeshi NAKAMOTO, Osamu KANEHISA, Yohei SUGAWA
    2011 Volume 77 Issue 782 Pages 3881-3890
    Published: 2011
    Released on J-STAGE: October 25, 2011
    JOURNAL FREE ACCESS
    The purpose of this research work is to produce micro part reinforced by unidirectional whisker in laser photolithography. Electrically conductive whiskers are added to liquid photopolymer. By applying electric field to this mixture, the axes of the whiskers are aligned along the direction of the electric field. Then, the photopolymer is solidified by an irradiation of UV laser in the desired shape. When the electric field is applied, rotating moment aligned along the electric field act the whiskers in the liquid polymer. However, when the value of electric field is small, the rotating moment becomes small. Therefore, the whiskers do not rotate and are not aligned along the electric field because the liquid polymer has the bingham property. The bingham property is measured and the value of electric field to rotate the whisker is examined both theoretically and experimentally in this paper. Using the above results, solidified polymer structures with micro size reinforced by unidirectional whisker are produced by this method.
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  • Michio UNEDA, Shintaro MURATA, Takashi NARISE, Tsutomu YAMAZAKI, Osamu ...
    2011 Volume 77 Issue 782 Pages 3891-3903
    Published: 2011
    Released on J-STAGE: October 25, 2011
    JOURNAL FREE ACCESS
    Lapping is generally used in fabricating high-accuracy hard and brittle materials. In lapping, slurry mixed free abrasive grains and water or dispersion oil is used. It is well known that the lapping characteristics are affected by actual slurry flow in the contact surface between the workpiece and lapping platen. Therefore, stabilization of slurry flow is required to improve lapping characteristics. This paper presents both quantitative evaluation method and results of slurry flow behavior at lapping process, and investigates the movement direction and velocity of slurry flow behavior. Single wafer lapping method was used for our experiment. Furthermore, digital image correlation (DIC) method was used for quantification. As a result, the following points were observed. (1) DIC method can evaluate slurry flow behavior among full-field observed photographed area. (2) Slurry flow velocity has not correlation with relative lapping velocity between the workpiece and lapping platen. (3) Slurry flows much into contact surface along a turn of lapping platen.
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  • Naoko GOHYA, Wanfu SUN, Yoshifumi AMAMOTO, Takuya SEMBA
    2011 Volume 77 Issue 782 Pages 3904-3915
    Published: 2011
    Released on J-STAGE: October 25, 2011
    JOURNAL FREE ACCESS
    A truing test was conducted to clarify the truing mechanism for flattening diamond grains on the hemispherical working surface of an electroformed diamond tool with a mesh size of #1 000 and a tip radius of 0.2 mm. A polycrystalline diamond disc of 0.5 μm primary grain size and 15 mm diameter was used as a truer. A concentric groove with a reverse profile relative to the hemispherical tool and a surface roughness of 0.5 μm Rz was preformed on the truer by laser machining and wet lapping. Truing was then performed by placing the tool in elastic contact with the preformed groove on the truer. It was verified through a truing test that primary diamond grains on the guide groove acted as multiple minute cutting edges so that 93% of the diamond grains on the tool working surface could be flattened when the tool was placed in contact with a groove of 50 μm depth and the contact load was set at 5.2 N.
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  • Naoki ASAKAWA, Yoshimasa KURIYAMA
    2011 Volume 77 Issue 782 Pages 3916-3925
    Published: 2011
    Released on J-STAGE: October 25, 2011
    JOURNAL FREE ACCESS
    The study deals with automation of deburring by an industrial robot. The aim of the study is a deburring on a paring line of a sand core for casting. For deburring by industrial robot without teaching, tool path of a robot is automatically generated by an image processing technology. However, the tool path tends to have positioning error. In general, most of deburring by an industrial robot copes with positioning error using force control. While the method to compensate the error is easy to use, position control is desirable since the deburring is a kind of cutting. Therefore, the system is developed to correct tool path positioning error using a displacement sensor in real time. The experiment is conducted to compare a workpiece outline with tool path generated from a workpiece image and to deburr the workpiece based on the path. From the experimental result, the system is found effective to remove a burr on a parting line of a sand core.
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Technical Paper
  • Toshiharu MIWA, Hideki AOYAMA
    2011 Volume 77 Issue 782 Pages 3926-3937
    Published: 2011
    Released on J-STAGE: October 25, 2011
    JOURNAL FREE ACCESS
    The acceleration of the product development cycle contin ues to be a significant challenge for manufacturing firms around the world. The present paper describes a product modularity creation method of product components that takes the uncertain relationships among the product components into consideration in order to reduce the development time in large-scale and complicated product development with technology uncertainty at the early stage of product development. We developed a probabilistic product worth flow analysis to evaluate each product component for prioritization with an uncertain relationship among product components. The product worth flow is defined as the development risk leading to the development delay. The method calculates the probabilistic distribution of worth flow of each product component based on the probabilistic relationship among product components with the Monte Carlo simulation and determines the priority of each component so as to minimize the variance of the feedback information across the product modules. The paper shows an example of a generic hair drier with a simple mechanical structure that this proposed method contributes to the reduction of the uncertainty of feedback information across the product modules by 61% compared to the conventional planning methods while maintaining the uncertainty within same product modules.
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  • Michiyasu OWASHI, Yuji MIHARA
    2011 Volume 77 Issue 782 Pages 3938-3950
    Published: 2011
    Released on J-STAGE: October 25, 2011
    JOURNAL FREE ACCESS
    In order to investigate the durability of the sliding surface of machinery, it is important to know the force acting on such parts and to evaluate stress distribution. Contact stress occurring on the surface of gear teeth is an important factor in determining bending stress on the gear teeth as well as load capacity. However, since the contact area of each gear tooth surface is extremely small, a conventional pressure sensor cannot be attached. For this reason, the authors developed a thin-film pressure sensor with a thickness of approximately 6μm for gear tooth surfaces by applying the same type of sensors which have been developed to measure oil-film pressure distribution in engine sliding surfaces, such as plain bearing and piston-pin bosses. A sensor with multi pressure sensing points connected by shared-type lead films was developed for narrow areas such as gear teeth surfaces, and can measure pressure distribution on the gear flank line when gears mesh together. In the results, the measured pressure was higher than the Hertzian pressure of line contact, and distributed unevenly in the axial direction. On the other hand, when the measured pressure was compared with Hertzian pressure of point contact, the calculated pressure was higher than the measured value. These disagreements seem to be caused by inexact gear geometry, nonparallel or uneven meshing and form of gear flank. In this study, details of the shape of the multipoint thin-film sensor, as well as the measurement results of pressure distribution are described.
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  • Naoshi TAKAYAMA, Takayuki AKAI, Munetaka WAKIZAKA, Yoshimi TAKEUCHI
    2011 Volume 77 Issue 782 Pages 3951-3960
    Published: 2011
    Released on J-STAGE: October 25, 2011
    JOURNAL FREE ACCESS
    The five-axis machining center with the table-on-table structure has newly been developed, and verified that the alignment accuracy of the rotating axis is easier to be ensured when the motion range of the rotating axis is larger. For the table-on-table type machine structure, it is practically very difficult to completely eliminate the alignment errors of the rotating axis even when the machine is sufficiently accurately assembled. The study deals with the method to enhance the motion accuracy with NC error compensation, based on the errors measured by using DBB. The alignment errors of the rotating axis on five-axis controlled machining centers are measured by using three different methods, and the results are compared. It found that remained alignment errors can be drastically reduced by conducting NC error compensation, whose amount is calculated on the basis of measured alignment errors.
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