Transactions of the Japan Society of Mechanical Engineers Series C
Online ISSN : 1884-8354
Print ISSN : 0387-5024
Volume 60, Issue 578
Displaying 1-50 of 51 articles from this issue
  • Hiroshi Satoh, Tsuneya Sugiya, Katsuzo Okada, Shinji Yamada
    1994 Volume 60 Issue 578 Pages 3233-3237
    Published: October 25, 1994
    Released on J-STAGE: February 26, 2008
    JOURNAL FREE ACCESS
    As long as each component part of pumps is produced within their fixed limit, and pumps are set with reasonable accuracy, it is generally considered that the bearing load generated by rotating shafts is small in vertical pumps. However, even though pumps are operated under the same conditions, the life times of bearings often makes a difference among the kinds of them related to their structure and / or materials, and problems with vibration are frequently experienced. Therefore, using an apparatus that is similar to a real pump, the influence of three kinds of bearings made of synthetic rubber (NBR), polytetrafluoroethylene (PTFE) and ceramics (SiC) on the vibration characteristics of the pump was investigated. As a result, an anomalous phenmenon of self-excited vibration was observed when ceramics bearings were used.
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  • Hidetoshi Kanzaki, Juzaburo Shibayama, Shunzo Watanabe, Masayuki Ichim ...
    1994 Volume 60 Issue 578 Pages 3238-3244
    Published: October 25, 1994
    Released on J-STAGE: February 26, 2008
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    The rotor of a three-phase induction motor occasionally produces an unstable electrical vibration of the power source frequency. In this paper, we studied the electromagnetic exciting force of two times the power source frequency caused by imbalance of the magnetomotive force on the stator core. The unstable electrical vibration induced by the exciting force was investigated by numerical calculation and experiment. The criterion for unstable electrical vibration was analyzed.
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  • Shinichi Noda, Isao Suzuki, Kazunobu Itomi, Fuminori Ishibashi, Sadaak ...
    1994 Volume 60 Issue 578 Pages 3245-3251
    Published: October 25, 1994
    Released on J-STAGE: February 26, 2008
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    The electromagnetic noise of an induction motor is very offensive to human ear. Most offensive electromagnetic noise is generated when natural frequencies of a stator core coincide with or are close to frequencies of the magneto motive forces. Therefore, in order to avoid such noise, it is necessary to estimate natural frequencies of the stator core in the design stage. In this paper, the effects of coil ends on frequencies and modes in the free vibration of the stator core are examined. It was clarified that each coil end does not vibrate as an additional mass, and constitutes an independent vibration system and produces free vibration coupling with the stator core. Based on these results, the authors provide a coupling vibration model with two degrees of freedom which consists of a double ring (stator core and coil end) connected by a spring. Each ring has one degree of freedom. Calculation of this vibration model yields natural frequencies of the stator which are similar to experimental values.
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  • Hisao Fukunaga, Hideki Sekine, Takashi Kumeda
    1994 Volume 60 Issue 578 Pages 3252-3258
    Published: October 25, 1994
    Released on J-STAGE: February 26, 2008
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    This paper presents an identification method for five bending stiffnesses of symmetric laminates using the vibrational characteristics. A rough value of bending stiffnesses is first estimated using the five lowest pairs of eigenfrequencies and eigenmodes. Then the estimation of bending stiffnesses is improved by minimizing the difference between the measured and calculated eigenfrequencies. The effect of the measurement errors on the identification results is also discussed.
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  • Koji Kimura, Hiroki Takahara, Masaru Sakata
    1994 Volume 60 Issue 578 Pages 3259-3267
    Published: October 25, 1994
    Released on J-STAGE: February 26, 2008
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    Parametric vibration of the liquid surface in a partially filled circular cylindrical tank is investigated. The tank is subjected to horizontal, vertical and pitching excitations. Nonlinearity of the liquid surface oscillation is considered in the response analysis of the sloshing motion. The nonlinear and parametric ordinary differential equations, governing the axisymmetric liquid surface oscillation and including the higher order radial modes, are derived by applying Galerkin's method. It is confirmed that the vertical excitation causes the parametric excitation. In addition, it is noted that the pitching excitation also causes the parametric excitation when the pitching axis does not intersect the symmetrical axis of the circular cylindrical tank. The time histories of the liquid surface displacement to the harmonic vertical excitations are calculated in cases where the dominant mode is axisymmetric and where it has nodal radiuses. An experiment was conducted using a model tank. Good agreement was found between the theoretical and experimental results.
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  • Katsutoshi Yoshida, Keijin Sato, Sumio Yamamoto, Kazutaka Yokota
    1994 Volume 60 Issue 578 Pages 3268-3273
    Published: October 25, 1994
    Released on J-STAGE: February 26, 2008
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    Since it is not easy to determine precise equations of physical nonlinear systems, some studies analyze chaos only by means of its time series, ignoring the use of system equations. From a similar point of view, we have already developed a method of statistical mechanics without system equations. In contrast to the above approaches, we discuss an identification technique which can determine the precise equations of chaotic systems. If we can determine the precise equations, it becomes possible to calculate valid quantities, such as Mel'nikov's function and bifurcation sets, for estimations of chaotic parameters. For this purpose, we use synchronization in chaotic systems. We define an error in the synchronization and its index, a statistical quantity called ISCS (index of synchronization in chaotic systems). We then consider a chaotic system and its approximation which is slightly different from the chaotic system, and show that ISCS tends to zero as the difference approaches zero. Numerical results show that we can obtain the best approximation if we choose the approximation whose ISCS tends to zero.
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  • Kazuhito Misaji, Hideki Kato, Koichi Shibata
    1994 Volume 60 Issue 578 Pages 3274-3280
    Published: October 25, 1994
    Released on J-STAGE: February 26, 2008
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    We have already proposed the analytical method for analyzing nonlinear vibrational properties of rubber, using experimental results from dynamic hysteresis characteristics tests. These tests are performed with rubber vibration isolators used in automobiles. Using the above method, we describe here a method for analyzing nonlinear vibration response properties of rubber in relation to frequency and amplitude of displacement. We can prove the accuracy of this method by directly comparing experimental results with the analytical ones of the dynamic response of a system, with one degree of freedom and modeling the rubber as a spring.
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  • Naoya Kojima, Yu Jian Chang, Yasutomo Fujimura, Hai Zhou
    1994 Volume 60 Issue 578 Pages 3281-3287
    Published: October 25, 1994
    Released on J-STAGE: February 26, 2008
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    The vibration intensity transmitted through a plate is usually referred to as a time-averaged intensity and is implicitly assumed to be steady. In this paper, the envelope vibration intensity was proposed, which has intermediate properties between the instantaneous vibration intensity and the time-averaged vibration intensity. For this purpose, the three-channel method, which can yield changing magnitude and direction of the intensity vector through a single measurement, was introduced. The experiments were carried out on a rectangular steel plate to investigate the effectiveness of the envelope vibration intensity, detecting the transient feature of the intensity vector. Then, detection limits of the envelope vibration intensity were also discussed. As a result of this experiment, it was clarified that the envelope intensity was advantageous in the detection of transient vibration and its propagation in a structure.
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  • Keiko Yoshida
    1994 Volume 60 Issue 578 Pages 3288-3292
    Published: October 25, 1994
    Released on J-STAGE: February 26, 2008
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    The purpose of this study is to solve the vibration responses of spacecraft equipment structures, especially light weight rigid panels, such as a solar array paddle or an antenna, excited by an low frequency acoustical noise field. In this paper, first, the direct loading pressure to the structure in a random sound field, is derived and the response calculation method using FEM is proposed. Second, the derivation of the direct loading pressure to the structure is experimentally verified, using a honeycomb panel of which the edge was bolted to a stand, in the steady-state sound pressure field. Finally, experimental results of the acceleration reponses of the panel in the random sound field are found to agree with the simulation results of this proposed calculation method. And the simulation results of the usual frequency response method contain a high degree of error compared with the results of the new method.
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  • Noritoshi Nakagawa, Young-Hun Yu
    1994 Volume 60 Issue 578 Pages 3293-3299
    Published: October 25, 1994
    Released on J-STAGE: February 26, 2008
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    In the present study, optimum distributions of unconstrained viscoelastic damping layer elements for plates are discussed from the viewpoint of the modal loss factor. The modal loss factor is expressed in terms of both the mechanical properties of the plate and damping layer and their thickness ratio. Optimum distributions of the thickness ratios of elements are obtained by sequentially changing the position of a piece of layer to another position which contributes to maximizing the modal loss factors. Results are presented for (1, 1) and (1, 3) modes of edge-fixed plates. These results indicate that the modal loss factor can be increased by as much as 200%, or more, by optimizing the thickness distribution of the damping treatment. The optimum configurations of the (1, 1) and (1, 3) mode of plates are revealed by positions where added damping treatments become most effective. The results are validated by both suitable experimental results and the calculated results obtained by the Ross-Kerwin-Ungar's model in the case of a uniformly treated viscoelastic damping layer over the entire area of the plate.
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  • Yoshihiro Tsuda, Hideyuki Tamura, Atsuo Sueoka, Hironori Matsuoka
    1994 Volume 60 Issue 578 Pages 3300-3307
    Published: October 25, 1994
    Released on J-STAGE: February 26, 2008
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    The characteristic which the Duffing oscillator with a softening spring property under harmonically stimulating force presents in the main resonant region has been investigated numerically. With regard to the structure which the system exhibits in this region, there exists another branch which appears due to bifurcation from the resonant branch at a certain frequency, in addition to the resonant and nonresonant branches. It has been clarified that many kinds of periodic solutions exist in the region between this new branch and the resonant one. Furthermore, besides the traditional harmonic solutions, i. e., resonant and nonresonant solutions, it has been shown that another harmonic solution appears, although it is unstable. This unstable solution enables us to reasonably explain the constitution of attractors in this resonant region. Chaotic phenomena, which appear due to period doubling bifurcation also exist.
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  • Masahiro Yoshihashi, Ken-ichi Matsuda, Ryo Kondo, Yohji Okada
    1994 Volume 60 Issue 578 Pages 3308-3313
    Published: October 25, 1994
    Released on J-STAGE: February 26, 2008
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    In the rolling process, steel sheet is supported by rollers and is apt to produce structural vibration. Sometimes the surface finish is damaged by this vibration. To overcome this problem, active vibration control has been proposed. Usually it requires a sensor and an actuator. However, the location of the sensor and the actuator is an important problem in active vibration control, and good sensors are expensive. This paper proposes self-sensing vibration control using a push-pull-type electromagnet. The electromagnet has two types of coils : a bias coil and a control coil. The displacement is estimated by using the mutual inductance change between the bias and the control coils. The estimated signal is linear to the gap displacement which is feedback to the control signal. The proposed method is applied to a simple experimental setup to confirm its capabilities.
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  • Kazushi Sanada, Ato Kitagawa
    1994 Volume 60 Issue 578 Pages 3314-3321
    Published: October 25, 1994
    Released on J-STAGE: February 26, 2008
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    A finite-element model of pipeline dynamics using an optimized interlacing grid system is proposed. By the finite-element method, basic equations of pipeline dynamics are approximated to be a set of ordinary differential equations which can be represented in state-space form. Steady laminar friction, unsteady laminar friction, and steady turbulent friction can be considered in the model. The interlacing grid system is optimized to make undamped natural frequencies of the model as close as possible to theoretical ones. The effects of important factors of the model are clarified. The accuracy of the model is demonstrated through simulation.
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  • Shinichi Sagara, Fujio Ohkawa
    1994 Volume 60 Issue 578 Pages 3322-3327
    Published: October 25, 1994
    Released on J-STAGE: February 26, 2008
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    This paper is concerned with a design of a Model Reference Adaptive Control System (MRACS) for a nonminimum phase system and its application to a position control of an underwater pendulum. The proposed MRACS consists of series and parallel compensators which compensate unstable zeros and a pole placement controller. The MRACS guarantees the stability and the convergency of the adaptive system. In order to verify the validity of the method, we apply it to a position control of an underwater pendulum with an undershooting phenomenon. Experimental results show the high performance of the constructed MRACS and the effectiveness of the proposed method.
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  • [in Japanese], [in Japanese]
    1994 Volume 60 Issue 578 Pages 3328-3334
    Published: October 25, 1994
    Released on J-STAGE: February 26, 2008
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    To discuss the dynamics of skiing, it is very important to understand forces and moments acting on the skier, ski equipment and snow. The purpose of the present study is to clarify numerically the reacting forces acting on a ski through snow. The reacting force is caused by the relative displace-ment between the ski and snow. On the other hand, the deformation of the skis and snow depends on the mechanical properties of the skis and snow. First, a numerical approach is proposed for estimating the deformation of the skis and snow. Next, numerical calculations are carried out for the ski subjected to vertical force and moment due to upweighting. Effects of flexural rigidity of the ski, camber height of the ski and spring modulus of snow on the reacting force are discussed.
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  • Tsuneo Yoshikawa, Xin-Zhi Zheng, Toshiki Moriguchi
    1994 Volume 60 Issue 578 Pages 3335-3342
    Published: October 25, 1994
    Released on J-STAGE: February 26, 2008
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    A system for displaying feel information while manipulating dynamic virtual objects is presented. A unified description of the dynamics of virtual objects based on the Lagrangian formulation is derived. The detection of the grasp states and the friction effects at the grasp points on a virtual object surface, which are important to help us recognize the object and handle it more dexterously, are treated explicitly. Display algorithms which create and present the dynamic operating feel of an object as well as the fricton feel on the object surface to the operator are proposed. Experimental verification of the proposed approches is performed and the results are outlined.
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  • Bin Xu, Toshiyuki Asakura, Atsushi Hiraizumi, Sakiichi Okabe, Yoshitug ...
    1994 Volume 60 Issue 578 Pages 3343-3348
    Published: October 25, 1994
    Released on J-STAGE: February 26, 2008
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    This paper is concerned with the stabilization of an electropneumatic valve positioner, whose dynamics is described by a nonlinear time delay system. When the neumatic tube between the controller and the actuator exceeds, for the explosive-proof, a certain length, the actuator will generate hunting due to the time lag of pneumatic pressure signals. To prevent hunting, a new stabilizing method has already been proposed by the authors. This work verifies the validity of the new controller from experimental viewpoints. First, the experimental apparatus with the new controller is explained. Next, the dynamic characteristics are examined, and especially, the pneumatic tube model which is important for the construction of controller is identified. Third, the stabilization of an electropneumatic valve positioner and its robust stability are verified through experimental studies. Moreover, the improvement of transient response is discussed considering the addition of a pressure-compensating circuit.
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  • Toshio Yoshimura, Koujirou Matsushita
    1994 Volume 60 Issue 578 Pages 3349-3356
    Published: October 25, 1994
    Released on J-STAGE: February 26, 2008
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    This paper is concerned with the leveling control and the design of opening areas of control valves for hydraulic shovels by the load sensing system. Firstly, the dynamics of hydraulic shovels with the load sensing system is modelled and the validity of the model is demonstrated by comparing the analytical results with the experimental ones. Secondly, the opening areas of control valves for the load sensing system are optimally designed with the criterion based on the leveling performance.
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  • Hitoshi Tsunashima, Takehiko Fujioka, Masato Abe
    1994 Volume 60 Issue 578 Pages 3357-3363
    Published: October 25, 1994
    Released on J-STAGE: February 26, 2008
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    A theoretical analysis and a simulation study on the dynamic characteristics of a Maglev transport vehicle with a mechanical levitation control system are performed. In this paper, the effect of the guide wheel stiffness and the dead zone element of the controller, which are expected to exert a large influence on vehicle levitation performance and ride quality, is described. After the construction of the vehicle dynamic model with the guide wheel stiffness, the stability criteria for the levitation are derived. The relationship between the dynamic characteristics of the vehicle and control lever ratio is analyzed. The simulation is carried out to confirm the obtained results by using the 17 DOF full model that includes pitching and rolling motion of the vehicle. The simulation results show that a low control lever ratio causes a sudden deterioration of levitation performance if there is a dead zone in the controller, and that a suitable control lever ratio which is unaffected by the dead zone is proposed.
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  • Syozo Tanaka, Shizuo Yamamoto, Akira Sone, Arata Masuda
    1994 Volume 60 Issue 578 Pages 3364-3371
    Published: October 25, 1994
    Released on J-STAGE: February 26, 2008
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    It has been available that the most of sound energy generated by machines would be radiated to atmosphere through the opening of an enclosure of a machine and it would be effective for proofing noise to control it. Then, in this paper, the methods to control the sound energy radiated through the opening of an enclosure are studied. That is, two kinds of mechanism, plate type and box type, to control the sound energy have been proposed from the point of view to arrest and dissipate the sound energy. The proto-type models of these mechanisms are fabricated and tested for evaluating theire effectiveness. After evaluation, the foundamental data to design the proposed mechanisms have been obtained by numerical simulations using BEM.
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  • Teruo Igarashi, Takafumi Yoshida, Kentaro Hattori
    1994 Volume 60 Issue 578 Pages 3372-3379
    Published: October 25, 1994
    Released on J-STAGE: February 26, 2008
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    Rolling motion is one cause of mechanical sound. Rolling sound may cause serious problems when it is excessive in machines and structures, for example. A series of studies have been carried out in order to obtain basic information for the reduction of rolling sound. This third report concerns the generation mechanism of the sound. Horizontal square steel plates with different surface finishes were simply supported at four points. Nylon and steel balls with different surface finishes were rolled at various rolling velocities on the plates, and the sound was measured using a condenser microphone. Surface topographies of the balls and plates were also measured by a device measuring the deviation from circular form and surface roughness, respectively. The signals obtained in the measurements were analyzed by an FFT analyzer. From the experiments, analysis and considerations, the generation mechanism of the sound was clarified.
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  • Takeharu Takasawa, Kenichiro Ohmata
    1994 Volume 60 Issue 578 Pages 3380-3385
    Published: October 25, 1994
    Released on J-STAGE: February 26, 2008
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    In this paper, a new type of small-sized vibration exciter using a magnetostrictive actuator is proposed, and the static characteristics of the actuator and the dynamic characteristics of the exciter are discussed experimentally. The vibration exciter is composed of a magnetostrictive actuator using a Terfenol-D (Tb0. 3, Dy0. 7, Fe1. 93) rod and a disk-mass system. The disk-mass system is attached to the cover plate of the actuator through four struts. The exciting force is obtained by the inertia force resulting from the vibration of the disk-mass system. The harmonic responses of the exciter were measured using a wave generator, a personal computer and a DC power supply. The maximum exciting force of 295 N at 78 Hz was obtained by using the mass of l0 kg. The exciting force was controlled by feedback control in order to obtain a constant exciting force of 20 N within 30∼100 Hz.
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  • Nobuyuki Kabei, Tomohiro Murayama, Kazuo Nagatake, Kiichi Tsuchiya
    1994 Volume 60 Issue 578 Pages 3386-3391
    Published: October 25, 1994
    Released on J-STAGE: February 26, 2008
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    We applied the technology of biomimetics to the development of an artificial muscle using a new theory of muscle contraction, and called it the electrostatic linear motor model. We designed and manufactured a fundamental electrostatic linear actuator that consists of a parallel-plate capacitor and a slider made of dielectric material. Since the actuator uses the water which fills the space between the two electrodes, it must be driven by an alternating current. The optimal frequency range for obtaining strong forces was from 5 to 10 kHz. We examined the influence of the applied voltage on the static force under the applied frequency of l0 kHz. The force increased in proportion to the second power of supply voltage. The force of 6.64 mN was obtained at 200 V.
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  • Nobuyuki Kabei, Tomohiro Murayama, Kazuo Nagatake, Kiichi Tsuchiya
    1994 Volume 60 Issue 578 Pages 3392-3397
    Published: October 25, 1994
    Released on J-STAGE: February 26, 2008
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    We applied the technology of biomimetics to the development of an artificial muscle using a new theory of muscle contraction, termed the electrostatic linear actuator model. A unit actuator of the artificial muscle consists of a parallel-plate capacitor and a slider. To increase output force of the actuator, we must integrate many unit actuators. To generate the maximum output force of the actuator, we attempted to determine the optimal aspect ratio (distance between electrodes of capacitor/length of electrode) that represents the integration rate of the actuator. It became clear through the computer simulation and the experimental measurement that the optimal range of the aspect ratio is from 1.6 to 1.7.
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  • Nobuyuki Kabei, Tomohiro Murayama, Kazuo Nagatake, Kiichi Tsuchiya
    1994 Volume 60 Issue 578 Pages 3398-3403
    Published: October 25, 1994
    Released on J-STAGE: February 26, 2008
    JOURNAL FREE ACCESS
    We developed an electrostatic linear actuator for use as an artificial muscle which consists of parallel-plate capacitors and a slider made of dielectric material. A unit actuator with one pair of electrodes generated the force of 6 millinewtons. In order for the actuator to generate a large output force, we made a two-dimensional integrated actuator with twenty pairs of electrodes whose aspect ratio (distance between two electrodes of capacitor/length of electrode) was 0.8 and width was 34 mm. It was confirmed that the experimental values of force agree well with the theoretical ones. The maximum output force of 42.3 mN was generated at the supply voltage of 200 V.
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  • Yoshiaki Araki, Hiroshi Harada, Masahiro Oya
    1994 Volume 60 Issue 578 Pages 3404-3409
    Published: October 25, 1994
    Released on J-STAGE: February 26, 2008
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    This paper deals with the application of an optimal preview control to an active vehicle suspension system. The responses of the front wheel are useful to estimate the disturbance from the road surface to be applied to the rear wheel. It is the strategy of this preview control that all state variables are measured and fed to the front and rear controllers, and also fed-forward as preview information of road disturbance to the rear wheel. The design is based on a two-degree-of-freedom dynamic model with two wheels. The advantage of preview control is shown by computer simulations.
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  • Kazuo Honma, Kichio Nakajima, Eiki Izumi, Yukio Aoyagi, Hiroshi Watana ...
    1994 Volume 60 Issue 578 Pages 3410-3417
    Published: October 25, 1994
    Released on J-STAGE: February 26, 2008
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    This paper first presents a system concept of a hydrostatically driven hydraulic excavator. In this system, pumps and actuators are connected each other. Then, the speed of actuators is controlled by the pump flow rate. Herein, a hydraulic excavator has 7 actuators and 4 pumps, and connection/disconnection of each pump and actuator are controlled by 3x4 directional control valves. Microcomputers execute the following controls : maximum pressure limiting (pressure cutoff control), pump absorption power control for prevention of engine stop and suitable power distribution to pumps, transient vibration damping, maximum acceleration limiting and resolved motion rate control of the excavator's arm. Furthermere, in this paper, we report the experimental study of pressure cutoff control which is a basic function for energy saving in a hydrostatically driven hydraulic excavator.
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  • Hiroshi Itoh, Takeshi Tsuchiya
    1994 Volume 60 Issue 578 Pages 3418-3424
    Published: October 25, 1994
    Released on J-STAGE: February 26, 2008
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    Presently, tracking control with high speed and high accuracy is seriously required in the field of robotics and machine tools. For the control problem, we previously proposed a preview control system which has a superficial evaluation term in its performance index, and we showed that the preview system is not effective for applying the problem in two cases. The first is when the tracking position is on the velocity vector of the desired signal. The second is when the desired signal does not change. In both cases, the term becomes zero, then the path error becomes large. To overcome the problem caused by the first case, we proposed intoducing an auxiliary superficial term into the perpormance index of the preview control system. In this paper, to overcome the problem caused by the second case, we propose the intoduction of a virtual axis to the system. The synthesis method for the new path control system is presented. To evaluate the effectiveness of the proposed control system, simulation studies are carried out. The simulation results show that the path tracking ability is markedly improved.
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  • Tadaatsu Satomi, Tsutomu Ogawa
    1994 Volume 60 Issue 578 Pages 3425-3430
    Published: October 25, 1994
    Released on J-STAGE: February 26, 2008
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    In the recent trend of using machines with artificial intelligence, one finds certain needs for analyzing and simulating the human control system. In the field of medicine, examination of the pupil response to a specific signal may help to study on a part of the autonomic nervous system, implying that it can play an important role as a diagnostic procedure. Furthermore, the control system model which is based on the pupil control transfer function derived from such study can be applied to the engineering field as well. This paper presents the development of a new pupil control analysis system and an analysis of the basic pupil response mechanism.
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  • Toshiki Oguchi, Atsushi Watanabe, Seiichi Kawata
    1994 Volume 60 Issue 578 Pages 3431-3439
    Published: October 25, 1994
    Released on J-STAGE: February 26, 2008
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    Although the exact linearization based upon a differential geometric approach is an effective method for designing a certain class of nonlinear control systems, it is not directly applicable to systems with delays due to the infinite dimensionality of the systems. In order to circumvent this difficulty, this paper proposes the use of a Smith-like predictor in the control scheme consisting of an input-output linearization of multi-input-multi-output nonliner systems with input time delays. Designs of the linearizing controller and the dead-time compensator can be done separately. Effectiveness of the present method is tested by simulation of a power plant control.
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  • Kazuhiro Kosuge, Tomotaka Itoh, Toshio Fukuda, Keizoh Sakamoto, Yasuo ...
    1994 Volume 60 Issue 578 Pages 3440-3445
    Published: October 25, 1994
    Released on J-STAGE: February 26, 2008
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    We propose a control system for a master-slave manipulator system having a rate-controlled slave manipulator. In this system, the master manipulator is stiffness-controlled in the Cartesian coordinate system, and the slave manipulator is damping-controlled in the Cartesian coordinate system. The desired velocity of the slave arm is given by a displacement of the master arm from a nominal position. The operator feels virtual contact force from the environment because the contact force is proportional to the displacement when the slave arm motion is constrained by the environment. The proposed method is experimentally applied to manipulators with three degrees of freedom. The experimental results illustrate the validity of the proposed system.
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  • Yasuyuki Adachi, Kazuo Yoshida
    1994 Volume 60 Issue 578 Pages 3446-3451
    Published: October 25, 1994
    Released on J-STAGE: February 26, 2008
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    In recent years, disturbance compensation control (DCC) which estimates and compensates a disturbance torque caused by the modelling errors of the system has been actively studied for motion control of ground and space robots. In this paper, this DCC is applied to the motion control of an unconstrained robot in water, regarding fluid force as a disturbance, and its effectiveness is considered by computer simulations. As a result, it was made clear that the DCC is very useful for the motion control of an unconstrained robot in water, because the fluid reaction forces which are very difficult to estimate can be regarded as disturbances, and also that a low-pass filter is useful for the measurement of noise to estimate the disturbance torque which is equal to the minimum-order observer using the Gopinath method.
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  • Katsuyoshi Tsujita, Kazuo Tsuchiya
    1994 Volume 60 Issue 578 Pages 3452-3459
    Published: October 25, 1994
    Released on J-STAGE: February 26, 2008
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    This paper deals with motion control of a biped locomotion machine. The system uses reaction wheels as torquers. The wheels generate the control torques without interacting with the gravitational field, and this, in turn, simplifies the calculation of the inverse dynamics. In this paper, some strategies for motion control of the system are developed based on inverse kinematics and inverse dynamics and verified by numerical simulations.
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  • Yasuyuki Uchida, Hidemi Hosokai, Fumio Hara, Yasunori Abe, Kouetsu Tan ...
    1994 Volume 60 Issue 578 Pages 3460-3467
    Published: October 25, 1994
    Released on J-STAGE: February 26, 2008
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    This paper deals with a mechanism and control method of a module-type mobile pipeline maintenance robot to clarify the adaptive feasibility of a lazy tongs mechanismto various diameters of pipeline. The robot basically consists of three modules with two joints, respectively between adjacent modules and is capable of straight and spiral maneuvering along the outside of a pipeline. Furthermore, the robot is capable of changing the length of its arm in order to move on the pipeline of various diameters, from 25 A to 100 A and of passing over obstacles such as reducers, flanges and other equipment. As the control method of the robot is very complicated, the modified dual control mode is introduced by employing the coordinate transformation matrices. The control method of passing over a reducer is shown with some calculated results. The compensating torque for the gravitational force is applied to each module independently to keep the holding force constant and to yield better diagnostic results.
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  • Fuminori Saito, Toshio Fukuda
    1994 Volume 60 Issue 578 Pages 3468-3475
    Published: October 25, 1994
    Released on J-STAGE: February 26, 2008
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    In this paper, we propose a seven-link brachiation robot, which has a structure much like a gibbon. The dynamic equations are derived in a general form and a simulator with a three-dimensional graphical interface is developed. The robot is examined for its potential for brachiation using initial controllers developed for three kinds of fundamental behaviors in brachiation : amplitude control behavior, target-approaching behavior and grip position feedback behavior. The oscillation state of the robot is represented by a radius and an angle of the phase plane. The radius representing oscillation amplitude is controlled by changing the pendulum length of the center of gravity with respect to the phase angle. The phase angle can also be employed for target-approaching to provide desired states. Simulation results show that the proposed robot may successfully achieve brachiation motion with the initial controllers for the three kinds of fundamental behaviors.
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  • Shigetoshi Shiotani, Toshio Fukuda, Takanori Shibata, Kyousuke Sasaki, ...
    1994 Volume 60 Issue 578 Pages 3476-3483
    Published: October 25, 1994
    Released on J-STAGE: February 26, 2008
    JOURNAL FREE ACCESS
    Image processing has been used in robot vision as a tool to establish the position of targets. Many algorithms using the template matching and artificial neural networks have been proposed for recognition. However, these algorithms are ineffective in computing cost and recognition accuracy in the case of recognition of overlapping targets. Therefore, we propose an effective algorithm for the recognition of overlapping targets using artificial neural networks which have learned movements of the human eye and the template matching. The artificial neural networks extract target candidates faster than conventional algorithms which find the candidates by moving templates of basic patterns in order. Then the template matching recognizes whether the candidates are targets or not. We compared the proposed algorithm with the conventional template matching algorithm with respect to the performance time and the recognition accuracy in the recognition of overlapping plant cells. The experimental results showed that the proposed algorithm recognized them faster than conventional algorithms and with high recognition accuracy.
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  • Toshiyuki Sawa, Yuichi Nakagomi, Takashi Hirose, Hiroyuki Kumano, Hiro ...
    1994 Volume 60 Issue 578 Pages 3484-3491
    Published: October 25, 1994
    Released on J-STAGE: February 26, 2008
    JOURNAL FREE ACCESS
    When a bolted joint is under thermal change, where the material of clamped parts is different from that of the bolts, a variation in axial bolt force is produced due to the difference in thermal properties between the bolts and the clamped parts. In this paper, a variation of axial bolt force in a bolted joint under thermal change, in which a hollow cylinder manufactured from aluminum alloy is fastened to a body (hollow cylinder) with a tap bolt manufactured from steel, is examined both theoretically and experimentally. In addition, mechanical behaviors of a bolted flanged joint with a flat cover in which the cover, the gasket and the flange are manufactured from aluminum alloy and tap bolts of steel are examined when the inner circumference of the joint is subjected to heat conduction. With the use of the finite difference method, the temperature distribution in the connection is analyzed. A variation of axial bolt force and a maximum stress produced in the tap bolts are analyzed. In the experiments, temperature distribution was measured by thermocouples, the variation in axial bolt force and the maximum stress produced in the tap bolts by strain gauges when the inner circumference of vessel was heated (cooled). The numerical results are in fairly good agreement with the experimental results.
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  • Seungchul Kim, Akihiko Azetsu, Masashi Yamauchi, Tsuneo Someya
    1994 Volume 60 Issue 578 Pages 3492-3498
    Published: October 25, 1994
    Released on J-STAGE: February 26, 2008
    JOURNAL FREE ACCESS
    In order to clarify the behavior of oil film between piston ring and cylinder liner, pressure measurement and visualization of oil film are carried out in parallel using a simulating rig. In this rig, the piston ring is simulated by a straight glass bar test piece while the cylinder is simulated by a reciprocating flat plate. As a result, the following results are obtained. The oil film pressure of the full film region before rupture is negative and the maximum negative pressure is -0.35 MPa, i.e., tension. Cavities are formed at 20°∼30° crank angles from dead centers in the full film region, and grow with the increase of the crank angle. Then, new series of cavities are formed at the rear edge of the test piece. These two series of cavities coalesce and the flow becomes perturbed momentarily. The negative pressure is detected at 20°∼30° crank angles from dead centers and is not released until coalescence of cavities takes place.
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  • Manabu Toshimitsu, Hiroko Fuse, Daisuke Konno
    1994 Volume 60 Issue 578 Pages 3499-3503
    Published: October 25, 1994
    Released on J-STAGE: February 26, 2008
    JOURNAL FREE ACCESS
    Spindle motors in data storage devices such as hard disk drives (HDDs), are required to have higher speed, highly accurate rotational performance and low power consumption. Utilization of a self-acting air bearing has been considered as an alternative of the exisisting precision ball bearings for its bearing system. A self-acting air bearing has not come into practical use partly because the performance of contact start stop (CSS) was not satisfactory. In this paper, we have utilized amorphous hydrogenated carbon (a-C : H) as a thin film lubricant of a self-acting air bearing to study its use from the viewpoint of tribology. A result obtained from the contact start stop testing is as follows : when amorphous hydrogenated carbon (a-C : H) was used on the sliding surface of a self-acting air bearing, it exhibited sufficient performance-[which was high enough to be equal to the required] for HDDs-almost more than 15 times that of liquid lubricant which has traditionally been accepted as surface lubricant for magnetic disks.
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  • Katsumi Inoue, Sung-Ki Lyu, Gang Deng, Masana Kato
    1994 Volume 60 Issue 578 Pages 3504-3509
    Published: October 25, 1994
    Released on J-STAGE: February 26, 2008
    JOURNAL FREE ACCESS
    A method is proposed for the estimation of the residual stress due to shot peening in carburized gears. Influences of the martensitic transformation of retained austenite and the strain induced at the tooth surface are considered, and the residual stress is estimated from the difference in volume expansion between the case and the core. The estimated residual stress is close to the stress measured by the X-ray method, though it is overestimated at the surface. The stress intensity factor is calculated by the influence function method, and the reduction of the factor due to the residual stress is demonstrated and discussed.
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  • Takeshi Ishida, Hongyou Wang, Teruaki Hidaka, Masataka Hashimoto
    1994 Volume 60 Issue 578 Pages 3510-3517
    Published: October 25, 1994
    Released on J-STAGE: February 26, 2008
    JOURNAL FREE ACCESS
    Since the K-H-V-type planetary gears with cycloid gears can be made compact and light, and have a large reduction ratio, high efficiency, and high torsional stiffness, they have been used in industrial robots and machines requiring precise positioning. The rotational transmission error of the K-H-V-type planetary gears with cycloid gears should be as small as possible in order to apply the planetary gears in various fields. In this paper, K-H-V-type planetary gears with cycloid gears were transformed into a two-dimensional model with twenty degrees of freedom, and the effects of machining and assembly errors of elements on the rotational transmission error were determined analytically, and some analytical results obtained were checked experimentally, giving the following results. The major errors affecting the rotational transmission error are the position error of holes for the crank cam in the cycloid gear ; runout and accumulative pitch error of the cycloid gear ; error in the crank cam ; the accumulative pitch error of the internal gear. Directions of position error of the hole, runout and accumulative pitch errors of one cycloid gear should be identified with those of the other cycloid gear respectively, so as to decrease the rotational transmission error.
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  • Hongyou Wang, Takeshi Ishida, Teruaki Hidaka, Masataka Hashimoto
    1994 Volume 60 Issue 578 Pages 3518-3525
    Published: October 25, 1994
    Released on J-STAGE: February 26, 2008
    JOURNAL FREE ACCESS
    The rotational transmission error of K-H-V-type planetary gears with cycloid gears should be as small as possible in order to apply these planetary gears to the industrial robot and a machine requiring precise positioning. In this paper, after the K-H-V-type planetary gears with cycloid gears were transformed into a two-dimensional model with twenty degrees of freedom, both the mutual effects of errors of elements and the effect of plural cycloid gears on the rotational transmission error were determined theoretically, and moreover the theoretical results were checked experimentally in some cases, with the following conclusions. (1) The rotational transmission error cannot be determined by superposition of each rotational transmission error produced by individual error. (2) The tooth profile error where the tip has a convex error of cycloid gear should be avoided to decrease the rotational transmission error. (3) The rotational transmission error whose frequency coincides with the carrier rotational frequency is produced by errors of cycloid gears or carrier and assembly error or accumulative pitch error of internal gear. (4) The rotational transmission error increases when the backlash increases. (5) Plural cycloid gears have a beneficial effect on decreasing the rotational transmission error.
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  • Shuiping Huang, Takeshi Ishida, Teruaki Hidaka
    1994 Volume 60 Issue 578 Pages 3526-3532
    Published: October 25, 1994
    Released on J-STAGE: February 26, 2008
    JOURNAL FREE ACCESS
    In a strain wave gearing (commonly known as a harmonic drive), the flexible spline (FS) is a thin-wall cylinder with external teeth, and the circular spline (CS) is a rigid ring with internal teeth. The load transmission between FS and CS is very complicated, because the large deformation of FS is caused by loads, and many teeth of FS and CS are engaged at the same time. However, it is very important, for analyzing the rotational transmission error, torsion rigidity and strength of the strain wave gearing, to study the load transmission. In this paper, the circumferential strains of external and internal surfaces of FS were measured by using strain gages. With the use of these strains, the tension and bending stresses were divided, and the relation between stresses and loads was obtained. Further, using the difference of the tension stresses caused by loads, tooth engagement zones of FS, which agreed well with the experiment results of tooth contact, and tooth load distribution were obtained.
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  • Hiroshi Gunbara, Shigeyuki Shimachi, Hiroshi Kawata, Tohru Kobayashi
    1994 Volume 60 Issue 578 Pages 3533-3538
    Published: October 25, 1994
    Released on J-STAGE: February 26, 2008
    JOURNAL FREE ACCESS
    To avoid the influence from the small displacement of gear axes under load, the authors propose that all contact normals of a tooth surface be at right angles to the direction of the small displacement induced at each contact point under load. On the basis of this state of surface normals, a few methods for tooth surface generation have been devised for realizing this concept. In this research, an hourglass worm gear having the above geometrical characteristics was made using the conventional methods of tooth surface generation and tooth bearing of the worm gear was experimentally tested. As a result, the validity of this design concept was proven.
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  • Hitomi Yamaguchi, Takeo Shinmura
    1994 Volume 60 Issue 578 Pages 3539-3545
    Published: October 25, 1994
    Released on J-STAGE: February 26, 2008
    JOURNAL FREE ACCESS
    This investigation examines the requirements for realizing high-efficiency finishing in a new internal finishing process by the application of magnetic abrasive machining. In this process, a magnetic force is generated between magnetic abrasives which is supplied to the inside of the tube and to the magnetic poles located around the outside of the tube ; this controls the finishing characteristics. Two factors may increase the magnetic force : (1) volume and magnetic susceptibility of the magnetic abrasive and (2) magnetic field distribution. We discussed factor (1) in our first report. The present report is concerned with factor (2). With regard to (2), the magnetic force can be increased by the enhancement of the magnetic field strength and its gradient over the finishing area. It was found that by increasing the excitation current, tapering the magnetic pole tip, and minimizing the clearance, the magnetic field strength and its gradient can be increased ; this leads to the increase in the magnetic force. It was also verified that the high magnetic force leads to high-efficiency finishing.
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  • Isamu Oda, Takeshi Doi, Hidetoshi Sakamoto, Mitsuharu Yamamoto
    1994 Volume 60 Issue 578 Pages 3546-3551
    Published: October 25, 1994
    Released on J-STAGE: February 26, 2008
    JOURNAL FREE ACCESS
    Plastic deformation near a crack takes an important role relating to the failure or the fracture of the structure. In the present paper, a nondestructive and noncontact technique for evaluation of the plastic region near a crack by using infrared thermography is proposed. The temperature rise of specimen surface near a crack in weldment is measured by the infrared thermography. It is assumed that the heated region by the work of plastic deformation corresponds to the plastic zone near a crack. The effect of the welding residual stress on the shape and dimensions of the heated region is examined in the present study. The temperature rise and the heated region are compared with the plastic deformation obtained by the elasto-plastic finite element analysis. In addition, the usefulness and the limitations of the application of infrared thermography to the evaluation of the plastic region are discussed.
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  • Kazuhiro Kobayashi, Masajiro Abe, Hiroshi Ito
    1994 Volume 60 Issue 578 Pages 3552-3559
    Published: October 25, 1994
    Released on J-STAGE: February 26, 2008
    JOURNAL FREE ACCESS
    It is important to realize the digging resistance in the design of excavators of continuous bulk handling equipment. Until now, resistance has been determined by analyzing the load acting on the excavator from experiments. If operating conditions change, experiments must be conducted again. The purpose of this study is to analyze the dynamic load acting on continuous bulk handling equipment and to clarify the dynamic behavior. In this paper, a theory for the digging resistance has been established using the distinct element method. In the simulation based on the theory, the handled bulk material is represented by an aggregation of grains. Deformation and fracture of the material are expressed by the movement of grains. Digging resistance is calculated as total contact force between the grain elements and moving wall elements of buckets. This theory was applied in the analysis of a case of coal digging. By comparing our analytical results with experimental ones, the validity of the theory was confirmed.
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  • Hidetoshi Tsukihara, Isao Nagasawa, Shigeto Aramaki, Takahiro Nakata
    1994 Volume 60 Issue 578 Pages 3560-3565
    Published: October 25, 1994
    Released on J-STAGE: February 26, 2008
    JOURNAL FREE ACCESS
    This paper describes a method of generating an assembly action sequence from the task skill and the assembly architecture obtained from product design. The state space of executing assembly actions are defined in terms of qualitative landmarks which consist for example, of the state of objects and the state of a robot. We will also describe a method of controlling actions (fine motion planning) by monitoring the state of a force sensor and a position sensor, and show a modeling style of hierarchical intelligent control.
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  • Takashi Irohara, Hiroyuki Yamamoto, Aya Saitoh, Kazuho Yoshimoto
    1994 Volume 60 Issue 578 Pages 3566-3571
    Published: October 25, 1994
    Released on J-STAGE: February 26, 2008
    JOURNAL FREE ACCESS
    This paper presents a technique to solve the facility layout problem with rectangular departments of unequal areas. This problem can be formulated as a combinatorial optimization problem to minimize the total cost owing to material flow between departments. It is, however, computationally timeconsuming to find optimal solutions for large problems, because they are highly combinatorial in nature. Furthermore, these problems exhibit many local minim. These properties make them suitable candidates for the application of simulated annealing, which is a stochastic optimization procedure. A suboptimal method is then developed, which is a new improvement-type technique based on simulated annealing. In this technique, a new algorithm for updating placement of departments is proposed. This algorithm enables the application of simulated annealing to solve the problems considered here. This technique also offers increased flexibility to the optimization process, making the solution much less dependent upon the initial layout. Numerical results are given to demonstrate the effectiveness of the presented technique.
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  • Naoki Uchiyama, Eiji Arai, Masanori Igoshi
    1994 Volume 60 Issue 578 Pages 3572-3578
    Published: October 25, 1994
    Released on J-STAGE: February 26, 2008
    JOURNAL FREE ACCESS
    Mechanical parts must be grouped for assigning assembly tasks to assembly machines and for generating assembly sequences. Though several methods to support the parts grouping have been proposed, their applicabilities are limited within specific problem domains. This paper proposes a more general method based on the imposition of constraints with respect to grouping. First, assembly processes and constraints of the grouping are represented by out-tree structures. Based on them, two algorithms are developed. One is to generate all feasible assembly processes and groups by solving pseudo-boolean equalities and inequalities. The other is to calculate the total number of feasible assembly groups to reduce the amount of computation. An example demonstrates the efficiency of the proposed method.
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