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Derivation of Symmetric Fundamental Periodic Solution by Cesàro's Summation Method
Hitoshi IMAMURA, Kohei SUZUKI
2004 Volume 70 Issue 691 Pages
609-616
Published: March 25, 2004
Released on J-STAGE: March 04, 2011
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A new calculation technique is proposed for getting symmetric fundamental periodic solution of the lumped mass discontinuous system to periodic excitation. This system is adopted as a typical piecewise linear oscillator having no stiffness. First, it is pointed out that the feedback superposition method which was formerly proposed can not be applied to this particular oscillator. Then, an improved calculation technique for getting the periodic pseudo-feedback response is newly proposed whereby converged infinite series and unconverged infinite series can be separated. According to this improvement, even unconverged series of the periodic pseudo-feedback response become to be evaluated by the Cesàro's (C. 2) summation to viscous damped system and those (C. 3) summation to undamped system, respectively.
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Derivation of Symmetric Fundamental Periodic Solution by Initial Value Corrective Extension Method
Hitoshi IMAMURA, Kohei SUZUKI
2004 Volume 70 Issue 691 Pages
617-624
Published: March 25, 2004
Released on J-STAGE: March 04, 2011
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A new analytical method to find the exact solution to lumped mass discontinuous piecewise linear system having no spring stiffness is proposed. In this study, we apply the pseudo feedback superposition method in order to determine the exact functional form of the summation of the infinite number of pseudo-feedback responses appearing derivation process of the fundamental symmetric periodic solution. First, for this stiffness-free discontinuous piecewise linear system, we assume the solution facing towards the future. Under this assumption, we have to evaluate unfavorable two terms; “trend” term and “offset” term which lead to failure of periodicity and symmetricity among the solution. Second, we propose an alternative method to derive corrected terms based on the evaluation of only finite terms summation. Solution calculated through the approach can be indentical to that through Cesàro's summation approach reported in the previous paper.
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Hiroshi SODEYAMA, Kohei SUZUKI, Norio IWATA, Katsuaki SUNAKODA
2004 Volume 70 Issue 691 Pages
625-632
Published: March 25, 2004
Released on J-STAGE: March 04, 2011
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Recently, Magneto-Rheological (MR) dampers attract a great deal of attentions from many researchers as the semi-active control devices. In the MR damper, a MR fluid is used. The properties of the MR fluid can be controlled in accordance with the magnetic field. Therefore, the force generated by the MR damper is adjustable by changing the magnetic field at the orifice of the damper. In this paper, the force-velocity relationship of the MR damper is analytically studied. Based on the fluid dynamics with the Bingham model and Herschel-Bulkley exact relationships between piston velocity and generated force are obtained. It is confimed that each analytical result can predict the behavior of the MR damper exactly.
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2nd Report, Medium-Scale Shaking Table Control Experiments and their Theoretical Understanding
Yuichiro SHINOHARA, Nobuyuki SHIMIZU, Eiji SATO, Koichi KAJIWARA, Shig ...
2004 Volume 70 Issue 691 Pages
633-640
Published: March 25, 2004
Released on J-STAGE: March 04, 2011
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National Research Institute for Earth Science and Disaster Prevention (NIED) is constructing a three-dimensional large-scale shaking table. For developing useful methods of operation and control for the table, we have started the study of operation and control for a small-scale shaking table, and then continued the study for a medium-scale shaking table. A final goal of the study is to obtain a guideline of operation and control for the large-scale shaking table. In this paper, the authors treat the study of operation and control for the medium-scale shaking table. The characteristics of the medium-scale shaking table with a non-linear structure are experimentally identified with displacement feedback control (Conventional Control). Control experiments were performed with the Conventional and the Minimal Control Synthesis (MCS) procedures. The MCS procedure has been proved to be effective to enhance the performance of the control for the medium-scale shaking table with a non-linear structure.
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Yoshimasa NISHIYAMA, Masaki TAKAHASHI, Yasutaka TAGAWA, Masashi YASUDA
2004 Volume 70 Issue 691 Pages
641-646
Published: March 25, 2004
Released on J-STAGE: March 04, 2011
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Microvibration control technology has been rapidly becoming important in a number of fields including superfine technoloby in semiconductor manufacturing and bio-technology in gene analysis. In this paper, an active 6 DOF microvibration testing device using air actuators is studied from the view point of control system design. In the previous study, a combination of dual model matching controller and off-line feedforward gave good reference following performance. However, an interference problem to other axes has not been solved. In this study, in order to solve this problem, an adaptive digital filter called Filtered-X is applied to the control system. The effectiveness of the proposed control system is verified through reference following experiments, when a test model is equipped on the table.
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Study Using a Rigid Body Model
Kazuo HIROTA, Tomohiro ITO, Tomomichi NAKAMURA, Kiyoshi NAMBU, Saburo ...
2004 Volume 70 Issue 691 Pages
647-655
Published: March 25, 2004
Released on J-STAGE: March 04, 2011
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A neutron reflector, a newly designed core internal structure, is supposed to be adopted to the advanced pressurized water reactor (=APWR). This neutron reflector is composed of multi-stage ring type structures and is installed in a core barrel with very narrow passages at the 4 corner portion. Thus, it is considered that the coupling effect with a core barrel through liquid will become very predominant due to very large added mass and added damping effects. The authors have evaluated the added mass and added damping using a simplified neutron reflector model which is a rigid, one-degree of freedom model, and systematically investigated the effects of various parameters such as frequency, liquid temperature, and so on. This report summarizes those results as a knowledge data base.
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2nd Report, Identification Method and Experiment by the Weighted-Incremental Least Square On-Line Method
Tea-Jin PARK, Yoichi KANEMITSU, Shinya KIJIMOTO, Koichi MATSUDA
2004 Volume 70 Issue 691 Pages
656-663
Published: March 25, 2004
Released on J-STAGE: March 04, 2011
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In this paper, we have conducted identification experiments on the mass unbalance and high order sensor runout in a turbo molecular pump supported by active magnetic bearings (AMB), by using the proposed identification method. Firstly, output signals from the displacement sensors are converted and stored in the real time Linux. The mass unbalance and high-order sensor runout are identified using the weighted-incremental least square on-line method from the stored displacement data. Next, by attaching known plural weights on the rotor, the resulting unbalance and higher-order sensor runout were identified using the proposed method. Finally, the reproducibility of the identification experiment and the effectiveness and accuracy of the proposed identification method were verified by an already-known higher-order signal, which synchronizes with the rotor and corresponds to the sensor runout, is added to the rotor and estimate the added high order input signal.
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Hiromitsu OHTA, Kunisato SETO
2004 Volume 70 Issue 691 Pages
664-670
Published: March 25, 2004
Released on J-STAGE: March 04, 2011
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Acoustic diagnosis system with condenser microphone has some attractive characters what is more cheaper for cost of devices of sensor, is not keeping contact with machinery components and is wide band range on frequency compared with piezoelectric accelerometers. This paper proposes a method to do condition diagnosis about strong non stationary signal generated by operating rotating machineries which are rolling bearings. Especially, a signal processing technique in order to eliminate non stationary noises including operating sound is described by adopting locally stationary AR model a kind of system identification. Further, the optimum order of locally stationary AR model is determined from presumption of division terms. The effectiveness of this method has been identified by experiment based on a rotary simulator device on rolling bearings.
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Acoustic Tube Coupled at One End with a Flexible Panel with a Spring-Mass System Attached
Hiroyuki SEINO, Hiroshi YAMAUCHI, Kimihiko YASUDA
2004 Volume 70 Issue 691 Pages
671-678
Published: March 25, 2004
Released on J-STAGE: March 04, 2011
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In previous papers, to clarify the features of sound field of a structural acoustic-coupling system, a rectangular prism with one or two flexible panels is analyzed by the authors. From a practical point of view, a rectangular prism with flexible panels with some additional masses attached is also important. In this paper, a rectangular prism with a flexible panel attached with a spring-mass system is considered. First, experimental study is conducted. Two noteworthy features are found. One is that the mode that has non-vibrated flexible panel exists. The other is that the fixed state, whose existence is confirmed in the previous papers can be removed. Then, theoretical study is made using a one-dimensional mathematical model. It is found this model can explain the features mentioned above.
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Fundamental Experiments for Glass Beads and Theoretical Analysis
Shuichi SAKAMOTO, Kotaro TAKAI, Yuji FUKAI, Kensaku YANAGIMOTO, Seiji ...
2004 Volume 70 Issue 691 Pages
679-686
Published: March 25, 2004
Released on J-STAGE: March 04, 2011
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This paper deals with the development of a new method for measurement of the height for granular material in a cylinder. For monitoring of automated filling processes of cartridges in a series production a new measurement method was developed which allows to detect rapidly incorrect products and to improve the process capability by the use of this method. The aim of this research work is to measure the level of granular material in a cartridge without contacting the material. The material is the mixture of the solid particles and air. The material is assumed as the porous media from the viewpoint of acoustics. As that, the inside of the cartridge, which is filled with granular material, is the acoustic system including porous media. The measuring method used the relationship between amount of granular meterial in the cartridge and the characteristics of the transfer function of the acoustic system is developed. The acoustic characteristic of the granular material, which is used for the theoretical analysis was also measured.
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Design of an Anti-Vibration Filter for a Feed Drive System
Soichi IBARAKI, Takuya TANAKA, Atsushi MATSUBARA, Yoshiaki KAKINO
2004 Volume 70 Issue 691 Pages
687-692
Published: March 25, 2004
Released on J-STAGE: March 04, 2011
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This paper presents a tuning methodology of a fixed-structure feedback controller based on the frequency-domain loop shaping technique. Although the present methodology requires to solve a nonconvex optimization problem, it offers quite a practical way to tune a feedback controller such that the closed-loop system exhibits the desired control performance. As an application example, the tuning of a linear feedback controller is demonstrated for a feed drive system driven by a linear motor. In order to suppress the structural vibration of lower frequency, one must tune the controller by taking into explicit consideration its phase dynamics, as well as its gain dynamics. The loop-shaping design based on the proposed formulation is quite effective in practice in such a case.
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Takahiko ONO, Hikaru INOOKA
2004 Volume 70 Issue 691 Pages
693-699
Published: March 25, 2004
Released on J-STAGE: March 04, 2011
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In emergency transportation, a patient receives the acceleration of the right-and-left direction when an ambulance turns a corner or changes a lane. Such acceleration causes the feeling of discomfort or carsickness. With the aim of realizing safe and kind transportation for patients, we prototyped the actively-controlled bed for an ambulance which reduces the patient's discomfort by rotating the bed around the body axis. The bed is actuated by a DC servo motor. The desired angle of the bed is calculated in real time from the right-and-left acceleration acting on a car, which is measured with the accelerometer located beside a driver. The purpose of this paper is to examine the effect of the rotating-type actively-controlled bed in terms of ride quality. In experiment, the subjects evaluate a degree of ride quality on a scale of five for every second. Compared to the normal fixed bed, the ride quality improves when the bed is actively controlled.
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In Case of Optimizing Antecedent Clause and Consequent Clause Simultaneously
Mitsuru JINDAI, Satoru SHIBATA, Tomonori YAMAMOTO, Akira SHIMIZU
2004 Volume 70 Issue 691 Pages
700-705
Published: March 25, 2004
Released on J-STAGE: March 04, 2011
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A pneumatic servo-system has essentially non-linear elements such an compressibility of air, friction between cylinder and piston. The control scheme with fuzzy inference is effective for such non-linear plants. However, fuzzy rules in the fuzzy controller should be adjusted optimally to realize excellent control performance. On the other hand, the genetic algorithm can easily obtain the optimum solution in optimum problems. In this paper, we propose a fuzzy control for the vertical type pneumatic servo system in which the antecedent clause and consequent clause in the fuzzy controller are optimized by the genetic algorithm. In this method, it is possible to realize excellent control performance, because the antecedent clause and consequent clause in the fuzzy controller are optimized simultaneously. Further, the effectiveness of the optimized scheme was confirmed by experiments using the existent vertical type pneumatic servo-system.
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Takehiko TAKAHASHI, Toshiyuki SATOH
2004 Volume 70 Issue 691 Pages
706-713
Published: March 25, 2004
Released on J-STAGE: March 04, 2011
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This paper gives a design method of discrete-time robust control systems that are subjected to reference inputs restricted in magnitude and rate of change. Based on the principle of matching, we derive a practical necessary and sufficient condition that ensures time-domain specifications in discrete-time. Additionally, we derive a practical robust matching condition based on the practical necessary and sufficient condition under the plant uncertainties in discrete-time. A simple design example of a speed control system of a DC servo motor is also given.
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1st Report, A Proposition to The New Method of Identification
Goro OBINATA, Tadateru KUROSAWA, Tadao KAWAI
2004 Volume 70 Issue 691 Pages
714-719
Published: March 25, 2004
Released on J-STAGE: March 04, 2011
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In this paper, we have proposed a new method for identifying specified parameters in linear systems. The method is based on Youla-parameterization, which is derived by pulling out the deviations of specified parameters to the references. The resultant parameterization takes a form of linear fractional transformation (LFT) and has an arbitrariness on the stable factors of parameterizing. We can utilize the arbitrariness to enhance the accuracy of estimating specified parameters because the stable factorizing in the parameterization means introducing a filter for suppressing the effect of observation noises. Two examples are given for illustrating the effectiveness and for showing the possibility of applying the method to fault diagnosis.
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Modeling Based on Experimental Identification and Autonomous Flight Control Experiments
Kensaku HAZAWA, Jinok SHIN, Daigo FUJIWARA, Kazuhiro IGARASHI, Dilshan ...
2004 Volume 70 Issue 691 Pages
720-727
Published: March 25, 2004
Released on J-STAGE: March 04, 2011
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We developed a small autonomous hobby-class unmanned helicopter that weighs about 9 kg, focusing on attitude and velocity models and controller design. Singe Input Single Output (SISO) transfer function models are derived from brief kinematical analysis and system identification for each of the helicopter dynamics of pitch, roll, yaw, and three direction velocities. We designed six separate controllers based on derived models using LQG and LQI control theory. The models and control structure are verified by experimental results. Accurate position control, namely, hover control and trajectory-following control, is achieved by a simple control algorithm using a designed attitude and velocity control structure. Robustness of the controller against wind was confirmed in a windy-day experiment. To verify robustness against the perturbation of physical helicopter parameters, the controller is applied to a larger helicopter.
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Daigoro ISOBE, Daisaku IMAIZUMI
2004 Volume 70 Issue 691 Pages
728-735
Published: March 25, 2004
Released on J-STAGE: March 04, 2011
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In this paper, a parallel solution scheme for calculating inverse dynamics independent to member stiffness of link systems is described. The solution scheme is developed by using the Finite Element Method, which evaluates the entire system as a continuum by subdividing it into finite elements. It calculates nodal force by evaluating the equation of motion in a matrix form, and the information from the entire system can be handled in parallel. Therefore, the torque curves can be obtained seamlessly without changing the numerical algorithm, even in such cases where the dynamics of the link systems would gradually change. Moreover, the inverse dynamics of link systems with various stiffness values can be obtained similar to rigid link systems. In this paper, the kinematics of the link systems are calculated in order to obtain a target trajectory required for calculating the inverse dynamics, by considering stiffnesses of the finite elements. Both algorithms for calculating kinematics and inverse dynamics are combined into a single program. Some numerical tests carried out to simple link systems show the validity of the proposed scheme in applying as a unified scheme independent to member stiffness values.
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Kazuaki NAGAYAMA, Minoru SASAKI, Kazuhiro HANE, Takeo MATSUMOTO, Masaa ...
2004 Volume 70 Issue 691 Pages
736-742
Published: March 25, 2004
Released on J-STAGE: March 04, 2011
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We have developed a low-cost atomic force microscope (AFM) system for the measurement of surface topography and local mechanical properties of cells. An AFM unit was combined with an inverted confocal laser scanning microscope (CLSM) to observe the AFM image and the CLSM image simultaneously. The unit consists of an optical lever unit for the measurement of cantilever deflection, a feedback control system for the cantilever height, a cantilever drive unit with a piezo actuator, and a
XY stage with large scanning area (150μm×150μm), which was attained by magnifying the deformation of piezo actuators by applying the principle of leverage. By assembling necessary parts by ourselves, the total cost of the system was reduced to about a million yen. Surface topography of the cells was obtained as the conventional AFMs in a contact mode. Mechanical properties of the cells were measured from the relationship between the indentation force
F, and the indentation depth
d during an indentation test. The
F-
d curve was fitted with a quadratic equation,
F=
k (
d+ (
p/2)
d2), where
k and
p are the indices of initial stiffness and non-linearity of the cell stiffness, respectively. We measured the mechanical properties of the bovine aortic endothelial cells with this system to find that the two indices increased similarly in the cells exposed to shear stress of 2 Pa for 24 h. The present system is useful for the studies of cellular mechanics.
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Norihisa TAKAHASHI, Mitsunori TADA, Jun UEDA, Yoshio MATSUMOTO, Tsukas ...
2004 Volume 70 Issue 691 Pages
743-750
Published: March 25, 2004
Released on J-STAGE: March 04, 2011
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This paper presents an 6-axis optical force sensor which can be used in fMRI. Recently, fMRI are widely used for studying human brain function. Simultaneous measurement of brain activity and peripheral information, such as grip force, enables more precise investigations in studies of motor function. However, conventional force sensors cannot be used in fMRI environment, since metal elements generate noise which severely contaminate the signals of fMRI. An optical 2-axis force sensor has been developed using photo sensors and optical fibers by Tada et al., that resolved these problems. The developed force sensor removed all magnetic components from the sensing part. It detected minute displacements by measure amount of light and light traveled through the optical fibers. However, there still remain several problems on this optical force sensor. Firstly, the accuracy is not high compared to the conventional force sensors. Secondly, the robustness is not enough against the contact force to the optical fibers. In this paper, the problems concerning to the acturacy and the sensor output stability has been improved by novel methods of fixing fibers and arithmetic circuit. An optical 6-axis force is developed based on these improvements, and usefulness of our sensor for brain function analysis is confirmed in fMRI experimentations.
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Jian HUANG, Isao TODO
2004 Volume 70 Issue 691 Pages
751-758
Published: March 25, 2004
Released on J-STAGE: March 04, 2011
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A flexible tool held by the end joint of a robot will be deformed when the robot is used to complete a contact task. Without establishing a deformation model of the flexible tool, the end position of the flexible tool can not be obtained from computing robot kinematics. In this paper, a position and force hybrid control method using the visual information has been proposed for a 6DOF robot to complete a contact task. To detect the end position of the flexible tool, two CCD cameras are used and a real time image processing algorithm is developed. An advantage of the proposed method is that establishing a deformation model of the flexible tool is not necessary. An online learning neural network is also applied to a position/force hybrid control system to decrease tracing error of position. Using the proposed method, a flexible tool held by a 6 DOF robot hand was used in experiments of tracing a given curve with a specified force. The experiments have been made successfully and the results demonstrate the effectiveness of the proposed method.
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Yasuhisa HIRATA, Kazuhiro KOSUGE, Hajime ASAMA, Hayato KAETSU, Kuniaki ...
2004 Volume 70 Issue 691 Pages
759-765
Published: March 25, 2004
Released on J-STAGE: March 04, 2011
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In this paper, we popose a decentralized control algorithm of multiple mobile robots which have been developed for manipulating a large or a long object in cooperation with a human. In this algorithm, each robot is controlled as if it has a caster-like dynamics around a representative point attached to the object and the manipulation of the large or the long object is realized easily in cooperation wit a human. The proposed control algorithm is experimentally applied to two omni directional mobile robots referred to as DR Helper and experimental results illustrate the validity of the proposed control algorithm.
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Rie KATSUKI, Jun OTA, Yusuke TAMURA, Takahisa MIZUTA, Tomomi KITO, Tam ...
2004 Volume 70 Issue 691 Pages
766-773
Published: March 25, 2004
Released on J-STAGE: March 04, 2011
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This paper presents a robot system for handling various objects in home or office environments. A fixed manipulator utilizes marks on objects. A mark consists of two parts. One is the outer part, which indicates its 3 D pose, and the other is a QR code, which is stored information of an object (e.g. its size). A QR code is a kind of 2D barcode. A user attaches several marks on objects. The manipulator accesses the information using a camera on its hand. The manipulator estimates pose of objects measuring marks and using least-squares method. Then, the robot can handle and convey the objects through planning a sequence of conveyance and a pose for grasp that is based on the pose of objects, candidates for grasp pose informed by the mark, and signals from proximity sensors. Experiments are conducted to verify the whole system.
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Hiroaki YAMAGUCHI, Tamio ARAI
2004 Volume 70 Issue 691 Pages
774-781
Published: March 25, 2004
Released on J-STAGE: March 04, 2011
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This paper presents a novel path planning methodology using Bezier curves for a cooperative transportation system with two car-like mobile robots. We first transform the kinematical equation of this transportation system into two-chain, single-generator chained form in a coordinate system where a path is a curved line axis and a straight line perpendicular to the tangent of the path is another axis. The carrier of the transportation system can follow any path as long as its curvature is two times differentiable. The orientation of the carrier is uniquely determined according to the orientation of the tangent of the path. We secondly set the path to be a Bezier curve and we arrange the controlling points of the Bezier curve based on the working environment of the transportation system, e. g., in order for it to avoid collisions wit obstacles. The validity of this path planning methodology is supported by computer simulations.
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Derivation of Driving Torque and Decrease of Maximum Driving Torque Using Time-Variant Gain
Kunio HATTORI, Hiroshi YAMAURA, Kyosuke ONO
2004 Volume 70 Issue 691 Pages
782-789
Published: March 25, 2004
Released on J-STAGE: March 04, 2011
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In this paper, we discuss an aerial posture control problem of a 2-link acrobat robot with nonzero initial angular momentum. First, the equations of motion and the law of conservation of angular momentum are shown. Next, we derive a strict feedback system in order to apply a backstepping procedure by a coordinate transformation. Then the control problem is formulated as designing a control law such that the state variables of the system go to the origin at a given time. We design a controller of the driving torque by applying a backstepping procedure to the system. In the control law, there are free gains which decide convergence speed of Lyapunov function. Constant gains and time-variant gains are examined. Then, it is shown that time-variant gains are useful in terms of control performance and input efficiency. Finally, we present simulation results to show validity of the Proposed controller.
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1st Report, Design and Development of the Prototype WL-15
Yusuke SUGAHARA, Tatsuro ENDO, Takuya HOSOBATA, Yutaka MIKURIYA, Hun-o ...
2004 Volume 70 Issue 691 Pages
790-797
Published: March 25, 2004
Released on J-STAGE: March 04, 2011
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This paper describes the mechanical and electrical design of a battery driven bipedal locomotor, WL-15 (Waseda Leg 15), made of 6 DOF parallel mechanisms. This locomotor is designed to employ as a leg module of multi-purpose locomotion systems. The locomotor, therefore, will he applicable to medical and welfare fields, entertainments, humanoid robots and so on. In the design of the robot, we have reduced the weight to the maximum extent, taking advantage of the features of the parallel mechanism which the mechanical rigidity is high. The weight of WL-15 is 57 kg including batteries and its height is 1.2 m. Using the developed bipedal locomotor, basic dynamic walking experiments with the step time of 0.96 sec/step and the step length of 0.1 m/step was conducted, and the effectiveness of its mechanism was confirmed.
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Hee-Byoung CHOI, Olivier COMPANY, François PIERROT, Atsushi KON ...
2004 Volume 70 Issue 691 Pages
798-803
Published: March 25, 2004
Released on J-STAGE: March 04, 2011
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This paper deals with the design and dynamic control simulation of a new type of 4-DOF parallel mechanism providing 3 translations and 1 rotation for high-speed handling and machining. This parallel mechanism is named as H4. A model-based dynamic control scheme is developed to improve the accuracy of the trajectory tracking. A simplified dynamic model is used for the H4 robot to decrease the cost of computation. A dynamic simulation is performed using ADAMS
TM. The Adept motion is used as a benchmark test to evaluate the effect of the dynamic control. The simulation results show that the proposed dynamic control dramatically improves the trajectory tracking accuracy.
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Nobuyuki NAKAYAMA, Hiroyuki KAWAMOTO
2004 Volume 70 Issue 691 Pages
804-811
Published: March 25, 2004
Released on J-STAGE: March 04, 2011
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Formation of magnetic bead chains in a magnetic field was numerically simulated with the Distinct Element Method in order to apply for improvements of a magnetic brush development system in electrophotography. Simulated chain configurations, length and slant angle. and dynamic chain forming process were compared to the experimental results. The 2-D calculation could not simulate quantitatively well the chain configurations and the process, because the magnetic interaction between beads was under estimated due to the neglect of the interaction force between three-dimensionally distributed beads. On the other hand, 3-D calculation showed good agreement with experiments and it is concluded that 3-D calculation is indispensable for the quantitative evaluation. It was also confirmed that chain configurations were determined approximately to minimize its total potential energy given by the sum of magnetic energy and gravitational energy.
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Katsumi WATANABE, Xu Ying, Hiroaki KATOH
2004 Volume 70 Issue 691 Pages
812-819
Published: March 25, 2004
Released on J-STAGE: March 04, 2011
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The driving link of nongrashof planar four-link mechanisms, that none of two adjacent links can make a complete rotation, oscillates in such a manner that coupler and driven links take different forms of two link chain in going and returning respectively. In this paper, the characteristic of relationships between the input and output angles is made clear. The coupler curve is classified according to the number of rotation and numbers of nodes, maximum curvature points, inflection points. Moreover, in order to perform one cycle motion of the nongrashof mechanism, the crank rocker mechanism whose oscillating range coincides with that of its driving link is designed. Pin gear trains to drive supplementally the driven link are presented so that the nongrashof mechanism may pass through limit positions.
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Guide Lines based on Simulation for Design and Grinding Condition
Toshihiko YAMAMOTO, Shuji NISHIYAMA
2004 Volume 70 Issue 691 Pages
820-827
Published: March 25, 2004
Released on J-STAGE: March 04, 2011
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A rotor housing is one of main parts that compose combustion chambers of Wankel engine. The inside of it is peri-trochoidal form is shape. It is ground with a grinding wheel at a fixed point on the locus of workpiece moved by a generating mechanism. Workpiece radius and speed at the grinding point vary considerably. Inertia force, torque and grinding force that are caused in the grinding process, elastically deform this mechanism and wheel axis system in proportion to the square of workpiece rotational speed. Therefore, the positional errors arise between a workpiece and a grinding wheel and those affect grinding form. To grind it efficiently and accurately, it is extremely important in the design process of grinding machine and in the processing of peri-trochoidal form to forecast quantitatively the ground form accuracy under such grinding condition. In this report, the form accuracy has been analyzed by grinding simulation system when the conditions variously change. Useful and effective guidelines are obtained for designing the machine and grinding the form.
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For Spur Gear Pairs
Hidehiro YOSHINO, Fumihiro OHSHIMA
2004 Volume 70 Issue 691 Pages
828-834
Published: March 25, 2004
Released on J-STAGE: March 04, 2011
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A simplified model for calculating deformation of a gear tooth is proposed. In this model, the gear tooth is expressed by many thin gears that appear at the sections perpendicular to the tooth helix. Each thin gear deforms as a cantilever by the tooth load, and load transmission between the thin gears is made by shearing. Therefore, the tooth deformation that generally falls into a three-dimensional problem can be calculated as a two-dimensional problem. Using the proposed model, the transmission errors and tooth contact patterns of the spur gear pairs under the loaded conditions are analyzed in consideration with interference between the tooth tip and the mating tooth root. To confirm the calculated results, the loaded meshing tests were conducted on the gear-testing machine. The test results gave good agreement with the calculated ones.
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1st Report, Evaluation through Observation of Surface Property and Experimental Stribeck Diagram
Tomoko HIRAYAMA, Hisashi ISHIDA, Noriaki HISHIDA, Hidefumi MAEDA, Hiro ...
2004 Volume 70 Issue 691 Pages
835-840
Published: March 25, 2004
Released on J-STAGE: March 04, 2011
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MoS
2-shot coating technology is recently focused as one of potential methods of surface modification to realize a low friction state. In this paper, performances of a small-sized journal bearing with MoS
2-shot coating, which is aimed to be applied to a spindle of precision equipment such as magnetic recording storage system, are experimentally investigated through the observation of surface property and Stribeck diagram. Scanning electron microscope (SEM) images and reflection electron microscope (REM) images of SUS surface with MoS
2-shot coating show that original MoS
2 particles are broken into smaller pieces at bumping against SUS surface by jet flows of highly pressurized air, and are forcibly embedded into the surface with forming micro-dimples. Results of coefficient-of-friction characteristics of shaft-sleeve interface of the journal bearing, i.e., Stribeck diagram, show MoS
2-shot bearing can realize a low friction performance at a low rotational speed and reduce the magnitude of stick-slip much compared with the case of no-coating bearing.
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Shintaro ITOH, Kenji FUKUZAWA, Hedong ZHANG, Yasunaga MITSUYA
2004 Volume 70 Issue 691 Pages
841-848
Published: March 25, 2004
Released on J-STAGE: March 04, 2011
JOURNAL
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An understanding of nanorheological properties of molecularly thin lubricant film is necessary to clarify the head-disk interface (HDI) of high-recording-density hard disk drives. The lubricant molecules are extremely confined to the head and disk surfaces, and the surfaces slide at a high sliding speed. The lower the flying height, the more the confinement affects the flying characteristics. However, few attempts have been made at clarifying the dynamic nanorheological properties of confined lubricant molecules. This is because the method for measuring the dynamic shear force has not been established. So, we have developed a new method of measuring dynamic shear force called “fiber wobbling method”. This method enables us to measure the shear force with a detection limit of about 1 nN. The frequency of shear is able to set to several kHz. The gap is controlled with a resolution of 0.1 nm. Using this method we investigated the effect of confinement on the dynamic viscoelastic properties of perfluoropolyether lubricant film on a magnetic disk. The results show that both viscosiy and elasticity of the lubricant film increase drastically when the gap is less than 13nm.
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Coating of Alkaline Powders
Qi GAO, Yasuhiro TANI, Toshiyuki ENOMOTO
2004 Volume 70 Issue 691 Pages
849-854
Published: March 25, 2004
Released on J-STAGE: March 04, 2011
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In order to increase removal rate of a silicon wafer, a new fixed-silica pad containing alkaline powders has been developed. But there are some problems to be solved, such as, adding alkaline powders deteriorates mechanical properties and uniformity of the pad and removal rate decreases with time. Moreover it is difficult to manufacture such pad after adding alkaline powders. Therefore, the coating processes of alkaline powders utilizing various coating agents were carried out. As a result, alkaline powders coated by polystyrene polymer were the most effective to solve, but coupling agent made more tough coating film by reaction with polyurethane polymer as matrix material of the pad. After coating process of KOH powders with titanate coupling agent, removal rate could become constant for a long time with better polished surface also. Instead of KOH powders, manufacturing of the pad with piperazine powders as an organic alkaline became possible by coating of the powders.
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Yu ISHII, Manabu TSUJIMURA, Masahiro OTA
2004 Volume 70 Issue 691 Pages
855-860
Published: March 25, 2004
Released on J-STAGE: March 04, 2011
JOURNAL
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Magnetic bearing technology is applied to a CMP wafer carrier to control the polish rate profile by tilting the wafer carrier during polishing. If no control is applied, the wafer carrier subsides slightly into the pad and is tilted 18×10
-5 rad by the viscoelasticity of the pad. The polish rate in the wafer outer area can be increased by tilting the carrier to the positive side; the polish rate of the wafer center area can be reduced by tilting it to the negative side. Constant current control leads to better control of the polish rate profile than feedback control. It has been reported to be possible to improve the polish rate profile by keeping the wafer carrier in a horizontal position using a magnetic control.
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Application to Drilling, Milling Using Face Mill and Cutting Using Circular Saw
Ikuo TANABE, Hasrizal Bin HASHIM, Truong Hong MINH, Hiroshi SHIMA
2004 Volume 70 Issue 691 Pages
861-866
Published: March 25, 2004
Released on J-STAGE: March 04, 2011
JOURNAL
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Turning with environment-friendly cooling method using water evaporation for the earth was investigated and reported by previous authors. In the turning using water evaporation, the tool life was twice of that of the dry cutting. Surface roughness of workpiece using this cooling was the same to that of dry cutting. Cylindricity of workpiece using this cooling was one third of that of the dry cutting. Other cuttings with environment-friendly cooling using water evaporation were investigated in this report. The cutting process are drilling, milling using face mill and cutting using circular saw. In drilling, water was supplied to the workpiece through a tool holder and a hole on the drill. In same case of milling using face mill, water was supplied on a few tips with carbon cloth through a tool holder and a holder of face mill. And in case of cutting using circular saw, water was directly supplied on the circular saw in the cover during the air cut. In this experiment, temperature changes and tool lives of each tool were measured. It is concluded from the results that environment-friendly cooling using water evaporation was very effective for improving tool life of three cases.
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Masahiro SASADA, Hitoshi KOBAYASHI, Isamu AOKI
2004 Volume 70 Issue 691 Pages
867-872
Published: March 25, 2004
Released on J-STAGE: March 04, 2011
JOURNAL
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Experiments and FEM analysis on small hole piercing were carried out. In this paper, small hole piercing is defined as piercing performed using punches that have smaller diameter than the material thickness. The results of this study clarified the followings ; 1) Shearing force, stripping force and pushing force are considerably affected by the friction between the punch flank and inner surface of pierced hole, 2) The use of tapered punch is effective for reducing frictional force, and 3) Increasing the linear portion at the punch tip increases the shearing force. The experimental and analytical results were also found to agree for these findings.
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Daisuke MURAT, Tetsumaro HIROI, Hisashi NISHIMURA
2004 Volume 70 Issue 691 Pages
873-878
Published: March 25, 2004
Released on J-STAGE: March 04, 2011
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New lumber compression process, named sandwich roll press method, was developed. In this method lumber is rolled with a pair of metal jigs because rolling process is more suitable than prevalent press process to manufacture long products such as bar or column which is necessary for wood market. In this paper, limit compression ratio and plasticizing conditions of new method were investigated experimentally, and bending test was performed for estimation of strength of the products. The results indicate that this new method has possibility to manufacture longer lumber compressed highly than the manufactured by press process and that plasticizing conditions don't influence surface appearance and bending strength of lumber compressed by new method as the conditions of press process. These results show the effectiveness of this new method.
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Itaru YOSHIMURA, Yoshinobu SATO
2004 Volume 70 Issue 691 Pages
879-885
Published: March 25, 2004
Released on J-STAGE: March 04, 2011
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Recently computer systems have been widely applied to safety-related systems for achievement of safety functions. This general trend forced IEC to compile IEC 61508 as a standard related to functional safety of electrical/electronic/programmable electronic safety-related systems, i.e., E/E/PE SRS (SRS). Currently JIS includes the translated standard of IEC 61508, JIS C 0508. In accordance with the standard, an SRS is specified with its safety function (s) and safety integrity level (s) (SIL) and the SILs to be allocated to the SRS are specified with four levels of safety integrity. The standard requires assessing the risk reduction achieved by SRS using appropriate probabilistic techniques for allocation of SILs to SRS. However, the relationships among SILs, operation modes and hazardous event frequencies are not always cleared up yet. This paper presents a new model using two Sequential Failure Logics in order to describe causation of hazardous events in the overall system composed of equipment under control (EUC), EUC control system (BCS) and SRS. The SRS is assumed to implement a safety function in a dynamic demand state and assumed to have no automatic self-diagnosis functions. Then, the relationship among a dangerous undetected failure of SRS, demands for actuation of SRS and hazardous events brought about in the overall system is formulated based on the model. Moreover, new demand modes of operation and estimations of Hazardous Event Frequencies are proposed for allocation of SILs to SRS.
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2004 Volume 70 Issue 691 Pages
886
Published: 2004
Released on J-STAGE: March 04, 2011
JOURNAL
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