In previous papers, chatter vibrations in an automotive wiper assembly were analyzed. First the equations of motion of a wiper assembly were derived by assuming that it is modeled by a two-degree-of-freedom system. Then the equations were solved for practical wiping speeds. The results showed that the equations could be used to explain the behavior of the wiper assembly. In this paper, the same equations are used to predict the behavior of the wiper assembly at low wiping speeds. It is shown that at such speeds chaotic vibrations can occur. For quantitative confirmation of the occurrence of chaotic vibrations, the Lyapunov exponents are obtained.

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Internal resonance of thin rectangular laminated plates with degenerate modes is investigated using the method of multiple scales. The plates are assumed to be simply supported along all edges, and both movable and immovable edge conditions are considered. In order to use the method of multiple scales properly, the definition of detuming parameter σ, which expresses the relationship between the linear natural frequency ω and the driving frequency Ω, is changed from Ω=ω+εσ to Ω=ω²+εσ. The influence of the lamination sequence and the edge conditions on two-mode responses of the plates is studied. The accuracy of the analytical results is confirmed by comparing them with results of numerical integration of the equation of motion. Furthermore, it is shown that the two-mode responses which lose stability via a Hopf bifurcation lead to chaotic motion.

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Fault-tree analysis was carried out to evaluate whether CRT displays are capable of maintaining display functions during earthquakes. When considering the possible failure modes, it is necessary to pay particular attention to the vibration of the internal components, such as the shadow mask and electron gun assembly. The natural frequencies and the seismic responses of these components were analyzed to evaluate whether or not the functional capabilities of CRT displays are affected. The CRT display vibration tests were performed using a shaking table, and the functional capabilities of the CRT display during simulated design earthquakes were verified.

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In order to reduce the unbalanced vibration of a rotating machinery with an overhung rotor, we propose a semi-active vibration control system. The overhung rotor is attached to one end of a simply supported shaft-rotor system, a rotor of which is installed in an electromagnetic actuator. The electromagnetic actuator can apply a semi-active control force to the simply supported rotor to reduce the vibration of the overhung rotor indirectly. In the analysis, we confirm that there are the optimum values of the PD-controller gains to reduce the vibration of the overhung rotor. When the vibration suppression of the overhung rotor near the 1st and 2nd lower critical speeds is treated, the optimal values for the PD gains are obtained approximatelIy by the principal of a dynamic absorber. The analytical results are confirmed by the experiment for an overhung rotor with semi-active vibration control system.

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This investigation treats the damped free vibrations of a bent sandwich beam having a viscoelastic core and elastic layers that are elastically constrained at both ends. In the analysis, the elastic constraints are represented by translational and rotational springs, and the transverse and longitudinal vibrations of the sandwich beam are coupled. The vibrational equation is derived and effects of the angle and position of the bent point on the damped natural frequencies and loss factor of the straight sandwich beam for the first mode are examined. The damped natural frequencies and loss factor obtained from the analysis are in good agreement with those obtained by the experiment.

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This paper proposes a active vibration control method for flexible structures arranged in parallel under large earthquake motions. In this method, actuators are placed between a pair of structures to control the undesirable system response due to strong wind and earthquake motions. The relative displacement of base point and the control sensing points are effectively used to device control law. We also propose a modeling method for making a multi degree of freedom model using the uncontrollability and unobservability to prevent spilllover which invites serious problem in the active control. In this paper, the reduced order model of control objects expressed by 3DOF system for controlling the vibration of first, second and third bending modes is constructed. In order to obtain the robustness, the control scheme is constructed by the use of the filtered suboptimal control technique combined into LQ control theory. Effectiveness of the control schemes is demonstrated by the seismic response control of a pair of flexible structures.

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Adaptive vibration control is a method that changes vibration system characteristics according to the vibration level. To construct adaptive vibration control elements that do not require any external energy, called passive adaptive vibration control elements, we have proposed a method that uses nonlinear viscoelastic materials. This paper describes how we constructed these elements using dilatant materials and reports on the experiments we conducted with them. The results show that the vibration of mass supported by these elements is reduced when the vibration level is high. They also show that vibration is isolated by these elements when the vibration level is low.

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In this paper, we present a method for reducing shocks experienced by patients when ambulances pass over humps which have been built on roads as a means of reducing speed of vehicles. It seems that the shocks affect ambulances that rapidly arrive at a scene of an accident and transport patients to hospitals, when the shocks are large. As a result of optimization of air springs and dampers of vibration isolaling beds for the ambulances, the optimum values of stiffness of the air springs and damping coefficients of the dampers are obtained and the shocks are reduced. The effect of variation of the factors on the maximum acceleration of patients is clarified, and the acceleration is compared with the maximum acceleration of drivers in passenger cars.

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A vibration simulator was utilized to evaluate the dynamic characteristics of a complicated mechanical system, which requires the total structures to be available. However, in the design stage, only one component is generally under consideration to improve the system dynamics. Therefore, it is useful to develop a hybrid vibration simulator using only the ready-made component which is called a real substructure, as if it behaves as in the total system. In this work, a hybrid model is built by the substructure synthesis method using the FE component model which was obtained by numerical analysis using the finite element method without a real structure, and an experimental model which was obtained by experimental modal analysis of the real substructure. This hybrid model was reduced to the degree of freedom of the connecting point, and we determined a few deciding numbers of excitation and excitation location based on the error ratio and by computing the virtual transmitted force. The real substructure was excited by a hybrid vibration simulator for realizing the vibration behavior in a total system with a modified excitation force, which compensated for the electrical and mechanical characteristics of the vibration simulator.

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According to previous experimental study, local vibration that forms natural mode (wave number 2) around reattachment point was observed on elastic tube wall downstream of stenosis. A peak exists in the frequency spectrum of this stationary random vibration. This peak is attributable to natural frequency of local vibration on the elastic tube, so the peak frequency depends on transmural pressure, and the power depends on Reynolds number. In biological blood flow both transmural pressure and Reynolds number are pulsatile, but flow in the tube was steady in that previous study. In this research, experimental observation was made on pulsatile flow. It was found that the vibration acts quasi-stationary random nature at least 1 Hz. And relation between the vibration and murmurs contained in Korotkov sound was a little discussed.

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According to previous experimental study, local vibration that forms natural mode (wave number 2) around reattachment point was observed on elastic tube wall downstream of stenosis. A peak exists in the frequency spectrum, and the peak frequency depends on both character and transmural pressure of the tube. In this paper, these effects on the peak frequency were discussed. Measured peak frequency was agree with natural frequency of ring model that is affected by the influence of hoop tension. Consequentry, it was found that the tube character dependence is attributable to difference of local vibration system of the tube, and transmural pressure affects the peak frequency as the effect of hoop-tension in the wall. Moreover, by the influence of fluid and medium, effective mass of the vibration system is increase, and, the natural freaquency is dropped.

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This report outlines deals with the method used of estimate sound radiation levels at a distant point by using the sound propagation characteristics and the volume velocity of the sound source. Radiation sound levels far from a vibrating source are estimated using the reciprocity theorem and an experimental model of rectangular diaphragm elements as the sound source, and by summing the levels of sound radiated from all the vibrating elements. Sound propagation characteristics of the space are obtained by reciprocally radiating a sound from a speaker located at the measuring point and measuring the sound pressure levels in the proximity of the vibrating source.

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This paper concerns numerical analysis of a certain class of structural-acoustic coupling problems via boundary integral equation formulations. The coupled vibration problem under consideration is modeled as acoustic fields with insulating wall of elastic plates. Plate bending is formulated in terms of integral equations derived by using the fundamental solution of static bending, and they are discretized using the boundary-domain-element method. For the acoustic field governed by the Helmholtz equation, the boundary integral equation formulation is presented and is implemented using the standard BEM. After assembly of these equations, a total system of equations is derived and solved under the given boundary conditions. A few examples are computed and results obtained are discussed, whereby the effectiveness and validity of the proposed solution procedure is demonstrated. Finally, computational results on the transmission loss due to the insulating wall are described.

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The authors propose the utilization of a MIF (mode indicator function) to estimate modal damping ratios approximately. The accuracy and the effect of this method are examined to determine its feasibility for use in experimental modal parameter identification. MIF is a straight-forward function derived from FRFs, and indicates the existence of normal modes. MIF is generally used to indicate undamped natural frequencies, but not for other purposes. However, MIF can be used to estimate modal damping ratios roughly as well as to estimate undamped natural frequencies. The authors propose using of MIF to set the initial values of modal damping ratios as well as the values of natural frequencies in any modal parameter identification method in the frequency domain.

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In this paper, the authors propose a new experimental spatial matrix identification method. This method is to identify, determine in other words, a set of the mass, damping and stiffness matrices that can represent the dynamic characteristics of an objective structure in a frequency range from DC up to some frequency of interest from experimental FRFs. The theory of the method is proposed at first. Then, the validity of the theory is verified by an identification of a frame structure, which is made of steel components.

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This paper describes a computer simulation study on performance of lateral guidance system for Dual Mode Truck. A stability limit of vehicle lateral motion is analyzed by using 9 DOF vehicle dynamic model. Relations between steering parameters and stability limit are shown. Experiments with actual Dual Mode Truck is carried out to show the effectiveness of the simulation study. Both the simulation study and experiment show that lateral guidance with one side guide rail causes unstable vehicle motion. It is shown that the unstable motion can be suppressed by cutting off the power steering equipment in the guideway.

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Inadequate track circuit shunting introduce the possibility of serious railway accidens. However, an thorough investigation into this phenomenon has not yet been made. It is difficult to quantitatively evaluate to overcome such factors as axle weight, the contaminant between rails and wheels, the rust on the rails and the roughness of the tread surface, which presumably influence the inadequate track circuit shunting. The authors investigated inadequate track circuit shunting using an experimental track circuit in their laboratory. As a result, they clarified the relationship between the abovementioned factors and the train shunting sensitivity of track circuits.

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In order to investigate the problems related to soil and construction machinery, such as a hydraulic excavator, an understanding of the physical interactions between the soil and the machine is essential. The purpose of this study is to experimentally examine actual excavation processes by observing various physical parameters, with the aim of realizing intelligent excavation machinery whose performance is not only to be automated but also optimized in terms of specific task criteria such as, energy consumption, operation time and excavation trajectory. In this article, we present experimental results using a real-sized bucket which is equipped with various sensing devices such as two-axis load cells and three dimensional stress cells. In accordance with the model bucket experiments reported in the previous study, two soil types were used, that is, sand and loam. Variations of the excavation forces/torques and stress distributions were measured during excavation.

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This paper describes the optimization method of the mechanism consisting of a set of links connected in a chain by joints, such as a robot manipulator. The purpose of the optimization is to design a set of links which is able to move more efficiently in a three-dimensional workspace. The fundamental idea of the optimization is based on minimization of the work of actuators. The work of the actuators is defined as the product of the actuator torque by the rotational angle of the actuator. The torque and the rotational angles are calculated using the equations of motion of the set of links when the free end of the chain moves at a constant acceleration from any location in the workspace toward an arbitrary direction for a short distance. The magnitude of the work shows the magnitude of the power of the actuators. Therefore, by determining the link dimensions such as length, mass value, center of mass, and momentum of inertia so as to minimize the performance function defined as the sum of the work of the actuators at any location in the workspace, the mechanism consisting of the set of links is optimized.

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Kinematic synthesis which involves difficult process of determining configuration of mechanisms is an important subject to improve the efficiency of design automation. This paper proposes a newly method of automatic design procedure for mechanism generation and arrangement. An approach using genetic algorithms is applied to the design method. We treat planer mechanisms composed from links and consider their arrangement under some design constraints such as obstacles, minimizing weight and input output specifications. The fitness function included in the genetic algorithm has arbitrary coefficients. The performance of the genetic algorithm is influenced by the values of the coefficients. Therefore we present a method of adaptive tuning of the coefficients to obtain optimum design during the execution of the GA. Some examples are shown and the effectiveness of the proposed method is discussed.

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In this paper, we propose new type of real genetic algorithms named adaptive real range (ARRange) genetic algorithms (GAs). In conventional real GAs, we simply set a minimum value and a maximum value for each design variable and divide the range into some specific divisions after decoding binary strings to integer. However, in such cases, we need to divide given ranges enormously in order acheive sufficient accuracy. Moreover, initially, we usually do not have any information on the minimum and maximum values. Thus, we have to set them ignoring the accuracy of the real values. In the proposed method, a range of real numbers will move adaptively in each generation by using the mean value and standard deviation of the previous generation. By using ARRange GAs, we do not have to consider the setting of minimum and maximum real value or number of bits for accuracy of real numbers. However, in ARRange GAs, we need four additional GA parameters which influence on the performance of GAs. In particular, two of these parameters greatly influence the convergence. We also present additional options that make the designer not to consider bothering of these presetting. In this study, we demonstrate the proposed method by simple numerical examples and demonstrate its effectiveness and characteristics.

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Equipment to measure the surface hardness of the human body has been designed for the purpose of estimating muscle generating force from the physiological view point. The surface hardness is defined as the reaction force of the body surface under predetermined thrust displacement. The sensor described here is suitable for analysis of human motion and multipoint measurements because of its compactness. From the results of experiments on elbow joints, a relationship was found between the measured hardness and the joint torque. The results also showed that body surface hardness was a function of the joint angle. Moreover, it was shown that muscle forces could be estimated by a neural network when the hardness and joint angle were given.

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In the case of severely destroyed knee joint, TKA (total knee arthroplasty) is indicated as surgical treatment. The design of a prosthesis is performed on objects that are (1) good fixation, (2) improvement of range of motion, and (3) endurance. The purpose of this study was to analyze dynamic behavior of knees with different tibial prostheses in TKA to design a tibial prosthesis which is hard to loose. At first, displacement and stress were defined as the standards for evaluating the degree of loosening and the three dimensional models of different designs of tibial prostheses were made by using CT images. Next, the degree of loosening on dynamic behavior around the prosthesis was compared among the models. As a result, it was found that the prosthesis with the keel which extended to the proximal tibial cortex tended to have less displacement and stress, thus the prosthesis with this design was thought to have less incidence of prosthesis loosening.

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The influences of the parameters, i.e., the friction coefficient between the club head and golf ball, the eccentricity and inclination of the head to the target direction and the surface shape of the head, on the release velocity, spin velocity and trajectory of the ball after impact, are investigated. A computer program that analyzes the dynamic contact problem with friction is constructed, and the impact phenomenon between the head and ball is numerically analyzed using this program. The influences of the parameters described above are investigated quantitatively. It is shown that backspin is the result of friction between the head and ball, sidespin is the result of eccentricity or inclination of the head, which is called the gear action, and the surface shape of the head influences the trajectory of the ball after impact, which is called the round effect.

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Space debris collision is one of the most serious problems for space systems operations and, particularly, a warning system is necessary to determine whether repairs will be needed to carry out the mission. For this purpose, this paper presents a procedure based on an inverse analysis to estimate the impact force and its location exerted on a spacecraft by using the arrival time differences between acceleration waveforms measured at more than three places on a structure. Simulation results are shown based on the analytical solutions of the structure vibration model with acceleration data corrupted by white noise.

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In this paper, the relationship between sound pressure and distance is described. We carried out an experiment, as a fundamental study to develop a machine with hearing characteristics of humans, on how accurately the intensity of a sound that is audible to humans and the distance from the sound source there of can be presumed. The method employed was AHP analysis. As a result of the experiment, the relationship between the intensity of the sound which a subject heard and the distance from the sound source was found to be consistent. The sound intensity value obtained experimentally was similar to the theoretical value for the distances from the sound source of up to 1 m. We utilized a white noise and a pink noise. We compared the a characteristics of noise and pure sound. The characteristics of the that two kinds of noise were found to be similor. The experiment clarified the differences between the characteristics of noise and those of pure sound.

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The authors have conducted research into a vision sensor system which is functionally similar to the human eye. We have designed and manufactured a special lens to realize this function. The lens system provides an extensive 120-degree visual field, by optically enlarging the image in the central area and compressing it in the peripheral area. In this paper, the authors propose a new method to detect a camera's location and gazing direction based on two parallel boundary lines of a road projected in the peripheral area, and show that it works precisely and efficiently. Subsequently, we apply this method to a curved road and compare the location detected from the boundary lines with the actual camera location, and establish that there is reasonable agreement between the two.

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We outline the design method of a multivariable PID controller based on frequency domain analysis. The method is based on the determination of multivariable PID controller parameters by achieving partial model matching so as to minimize performance functions with respect to the relative model error between the loop transfer function matrix of the control system and the reference model. The proposed method is evaluated experimentally using position control of a parallel pendulum system. The effectiveness of the method is confirmed through practical examination.

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This paper describes the robust motion control of a flexible micro actuator using a linear quadratic gaussian optimal control with the loop transfer recovery (LQG/LTR) design technique. The flexible micro-actuator is made of poly vinylidene fluoride (PVDF). It is important to design controller for the flexible micro actuator that have the robust performance, which is the ability to guarantee acceptable performance inspite of plant parameter variations, modeling errors due to high-frequency unmodelled dynamics, disturbances and sensor measurement noise. LQG/LTR system design theory is an important modern technique used in the design of control systems which have a robust stability margin. It relies on the full recovery of guaranteed robustness properties of the LQR with full-state feedback. The Nyquist diagram shows that the designed controller has a satisfactory gain margin and robust performance. Both numerical and experimental results demonstrate the robust performance of the motion control of the flexible micro actuator for plant parameter variations.

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This paper discusses the OGY method based on a chaotic time series that produces a return map of complicated structures. Previous studies on this subject dealt only with relatively simple return maps of structures, such as a one dimensional arc, because it is easy to calculate quantities required for the OGY method from the simple return map, but not from a complicated one. Since chaos arising in real systems may not produce simple return maps, a method that produces a simple return map suitable for the OGY method is needed. To solve this problem, we focus on a part of the time series of a chaotic behavior that produces a complicated return map. This process simplifies the complicated return map and makes it easy to calculate quantities for the OGY method. We take a numerical example of a chaotic behavior in the burst state. The results show that it is possible to construct a simplified return map from the complicated one by only using a part of the time series within selected time intervals and that the OGY method works well with the simplified return map even if the partial time series constructing the map has critical and unstable characteristics.

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An autonomous robot that acts in a complex environment needs to learn which action should be performed in each external state. Therefore, we propose a new control architecture for autonomous robots. The control architecture includes a learning system, which consists of globally coupled chaotic elements. A chaotic element has dynamics which are designed so that the elements can collectively execute reinforcement learning. Although each element continuously updates its internal state according to its intrinsic dynamics, this local processing collectively determines an action of the robot and allows it to interact with its environment. The result of this interaction returns to the elements as a payoff, which changes the dynamics. We carried out computational experiments for a navigation task. The results show that the chaotic elements self-organize so that an autonomous mobile robot exhibits such behaviors as goal-reaching, wall-following and collision avoidance.

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This paper presents an efficient computational algorithm of model-based adaptive control for closed-loop robots. The algorithm is an extension of the computational algorithm for serial-link robots, which was derived by Kawasaki and Bito. The proposed algorithm is implemented to a 6 D.O.F robot with parallel-link mechanism using a 32 bit DSP. Experimental results of trajectory control are also shown.

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We are developing a wheeled robot called a 'variable structure type four-wheeled robot' which, with a simple structure, has ability to pass over a step. We already realized its dynamic passing over a step whose height is known. Therefore, in this paper, we propose a control method to pass over a step whose height is unknown. We mainly discuss the evaluation and planning method of a dynamic trajectory by considering the robot's stability against falling down in landing, and the control method to finish landing at a constant position on the step. We also confirm the possibility of detecting the height of the step by using the existing rotary encoder without adding any external sensors. As the result, we have successfully realized an experiment of this robot's going up steps whose height is unknown within only four seconds.

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This study examines the friction welding behaviors of SiC particles (20 vol.%) AC 8 A and Al₂O₃ particles (15 vol.%) A 6061 composite aluminum alloys. In this study friction welding tests were carried out for similar and dissimilar materials, and we verified the validity of the application of friction welding by examining the welding condition, structure hardness distribution, tensile strength and carrying out an ultimate analysis of the welded interface.

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The effects of particles interposed between rubbing surfaces on the friction and wear characteristics of silicon carbide were examined. The interposing particles tested were silicon carbide and silicon dioxide with different shapes and grain sizes. Interposition of the particles between silicon carbide specimens resulted in considerable improvement of their friction and wear performance, since the interposing particles prevented edge loading and mitigated local contact stress concentration. Silicon dioxide particles with a lower hardness and fracture toughness than those of silicon carbide were better able to improve the friction and wear performance than silicon carbide particles. in addition, silicon dioxide particles with ionic bonding easily formed a thin surface film compared with silicon carbide particles with covalent bonding leading to a remarkable reduction in friction.

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The dry friction and wear characteristics of cast iron at high sliding speed and high contact pressure are described with a focus on the conditions of transition from mild wear to severe wear and the friction characteristics in the mild wear region. Wear tests were carried out using a pin on-disk test device in which the cast iron pin slid on a mild steel disk, and the variations of the friction force, the wear rate and the temperature rise with the sliding distance were measured. From the experimental results, the following points were clarified. First, the transition from mild wear to severe wear occurs when the friction induced temperature rise of the cast iron pin reaches a certain value which is strongly related to the decrease in hardness of the cast iron pin. Secondly, the mean coefficient of friction in the case of mild wear can be determined from the temperature rise at the transition point or the mean friction power in the mild wear region. It also depends on the PV value, i.e. it decreases with increasing PV value.

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Abnormal vibration of a single ball bearing subjected to an axial load was studied. The primary purpose of this study was to elucidate the mechanism of generation of the abnormal vibration. Therefore, we examined the following points: the system of the abnormal vibration, the excitation acting upon the system, and the relationship between the abnormal vibration and the lubricant properties. From the experimental results, the analytical results and related considerations, it is clear that the abnormal vibration is a forced self excited vibration in the angular direction of the outer ring of the ball bearing having a nonlinear spring property.

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A concept for a new type of hob for an hourglass worm wheel has been proposed. The hob can be used repeatedly when the cutting edges become worn. This concept was applied to the design of a hob cutter for the principal part of the wheel tooth surface generation of the hourglass worm gear generated by use of a tool with a conical surface. In this paper, the authors, increasing design elasticity, describe design of such a hob to generate the whole tooth surface. Numerical calculation results show that the hob generates not only the secondary part of the wheel tooth surface but also the primary part of it with high accuracy after regrinding of its face surface.

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Polybutylene terephthalate (PBT) has slightly lower mechanical strength than polyacetal (POM), however, with its minimal water absorption and small friction coefficient this plastic is considered attractive for use. However, the fact that its elongation is large is a problem. Since a plastic gear having a large elongation is deformed by applying a large force to the gear and its tooth from is changed by it, abnormal wear may be generated in the gear. Thus, PBT has not been considered the best gear material. In this research, using gears manufactured with PBT, investigations on its fatigue strength as well as its sliding properties such as gear wear and change in tooth form were carried out using a running test. Furthermore, by comparing the results with those of POM gear, the use of PBT as a gear material was evaluated.

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In this paper we describe a newly developed cutting force measuring device with high response speed and fine resolution. It can monitor cutting process as well as tool wear during high-speed endmilling of hard steel materials. The device enables precise determination of an transient cutting force which is generated by each cutting edge of an endmill tool rotated at a speed of 20000 rpm. It is found that the cutting force and its waveform in high-speed milling are affected markedly by the cutting parameters and tool wear. The cutting force proportionally increases with increasing cutting speed. When the cutting speed exceeds a certain speed, the cutting edges rapidly wear out, also the increasing rate of cutting force changes quickly.

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In this paper we describe a newly developed cutting force measuring system with high response speed and fine resolution. It can monitor the cutting process using various tools as well as the tool wearing process during high-speed endmilling of hard steel materials. The system enables us to precisely determine a transient cutting force action which is generated by each cutting edge of various helix angled endmill tools rotated at speeds of 40000 rpm. It is found that the cutting force and its waveform in high speed endmilling are sensitive to by the helix angle and tool wearing process. When the helix angle is 45 degrees, the cutting force and the flank wear of each cutting edge generated is smaller than those for angles of 15 and 30 degrees.

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This paper describes some unique phenomena observed in the diamond cutting of aluminum in vaccum, which are (1) a strong dependence of the cutting force on gas pressure, (2) a deposited product like a buildup edge, which is formed at pressure above 10 Pa in oxygen gas, (3) an adhering and sticking of cutting chips to the workpiece surface, which is observed in argon gas and in vacuum under 10² Pa in oxygen gas. As a result of experiments, the cutting force change with pressure is seen to be dosely related to a depositing process on a rake face and a physical interaction between the chip surface and a rake face. The deposit process can be explained by a chip oxidation which is enhanced by high temperatures during high speed cutting.

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Nowadays, Sugi (Japanese cedar, Cryptomeria japonica D. DON) accounts for half of the wood resources planted in Japan and is highlighted as a sustainable wood resource. However, the efficient use of Sugi harvests is limited, because the strength of Sugi is considerably lower than those of hardwood, such as Buna (Japanese beech, Fagus crenata BE.) and Keyaki (Zelkova serrata MAKINO), commonly used in the manufacture of furniture. Here, we report the possibility of a closed-die forging method which can convert low-strength lumber from Sugi plantations into high strength panels. Green wood specimens cut from a Sugi log were boiled and large compressed into cylindrical panels using closed die forging operations. The cylindrical panels were then permanently fixed using a steaming treatment. The deformation behavior, forming limit and strength properties were investigated experimentally. It was found that the proposed closed die forging method is comparable to the conventional bending method in terms of the forming limits. The limiting ratio of the radius of curvature to the thickness was about 12 for the modified closed die forging method using the Thonet-type technique, which prevented cracking, although the limiting ratio is about 30 for the conventional bending method. Furthermore, results showed that the strength of the cylindrical panels can be improved by the closed-die forging method; the bending strength of the cylindrical panel with 0% moisture content was the same as that of aluminum, and with 15% moisture content, increased by approximately 25% over those of Buna and Keyaki lumber panels at the same moisture content. It was, therefore, concluded that the proposed method for producing high strength panels could be considered to be a promising process from the viewpoint of the efficient use of harvested Sugi.

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Effects of the wire shape in bundles and the wire feeding conditions on shape of formed coils are studied experimentally. Although they are important problems in the cold coiling of springs, they have never been studied because of their complexity. The main results are as follows. 1) The wire shape in bundles and the inclination angle of the reel plane produces the combined load of bending moment and torsional moment on wires during coiling by a deformation trend of the wires, which is related to the changes of shape of formed coils with the interaction between yield-point loads. 2) The effect of feeding conditions on shape of formed coils seems to decrease as feeding wires straighten. 3) Instructions on the selection of the wire shape in bundles, the setting of the reel plane and on the compressire force of feed rollers are given on the basis of the experimental results.

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During automobile body design, the designer's intentions are initially represented in the form of a physical model, where feature lines are first drawn on a clay model, and points are then digitized using CMM (Coordinate Measurement Machine) and fitted to parametric curves and surfaces. This provides the master mathematical model for car styling. In this paper, using the variational principle, a general surface smoothing scheme is proposed to fit the grid points, boundary points and scatter points to the smoothness parametric surface. It has been a long standing research problem to smooth scatter data points to surface. Some methods had been proposed to do it using radial functions, partial derivative equation, integral equation or the triangular parametric surface form. However our method is using the squared parametric surface form. A variety of curves and surfaces with different smoothness can be obtained with the aid of parameters such as approximation and smoothness weights, segment or patch numbers and the distribution of approximation and smoothness weights. A car body was finished to show the usefulness of this proposed method.

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An object-oriented CAE system has been developed to improve the efficiency of the development of air conditioners. This refrigeration cycle analysis system can be used to evaluate driving characteristics such as the refrigerant condition and heat exchange capacity. In using an object-oriented approach, we consider each component of the cycle to be an object and define component classes using a hierarchical structure. We also consider calculation convergence and branching to be objects, thus making it possible to represent the analytical algorithm by combining objects. We implemented these concepts from an icon-based environment which guides the user in constructing a cycle diagram. Once the cycle diagram is completed in this manner, the refrigeration cycle is automatically analyzed.

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Time information frequently plays an important role in the areas of design and manufacturing. The processing of time information data is done by application programs in different ways. The authors developed a modeling system for time information in which various facts and conditions concerning temporal situations are described, processed, and inferred in an integrated way. In this paper we outline an approach for realizing the system and propose the system requirements, architecture, and basic functions. Based on these proposals, a modeling system for time information, labeled Time Information Manager (TIM), was developed and applied to some examples which contained both qualitative and quantitative information about temporal points and intervals. TIM is able to demonstrate the effectiveness of time information modeling.

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In modeling autonomous distributed manufacturing systems, a basic module of the net structure in the colored Petri net is introduced to describe the configuration of a machining cell and its autonomous decision making for real time scheduling. The arc expressions and transition guards are used to express the local decision making activities and the progress of the part process in each module. Three types of colored tokens which are the part token, the machine token and the AGV-token are introduced to record their own current states. The local decision making and information processing are made on the local computer attached to each machine. The whole system which consists of several machining cells can be represented by connecting the corresponding modules in which the transporting transitions between machining cells play the role of the interface between modules. The central computer makes the transporting schedule of the AGV by coordinating the transporting orders from various machines.

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For successful concurrent engineering, it is important to form a well organized team, outline good task processing and manage it in detail. The purpose of this research is to clarify the relationship among factors related to these task processings, and to establish a framework for systematic approaches of understanding, analyzing and designing the activities. In this paper, various activities observed during task processing are analyzed. From an individual viewpoint, nine factors and five primitive actions are extracted, and from an organizational viewpoint, four more factors and three typical processes are extracted. These factors and actions observed for group work are considered to form a structure in the space expanded by organization, task and time. The authors named it the organizational task processing structure (OTP structure). Its basic concepts and composition are explained and the relations between the OTP structure framework and other studies are discussed.

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For successful concurrent engineering, one should understand how each member of the design task carries out his processes in the organization. All task processes conducted in the design task form a kind of structure in which various factors are related to each other in a complicated way. The authors named this the organizational task processing structure (OTP structure). In this paper, the authors propose a method for OTP structure modelling, named ScoPy (Simultaneous and Collaborative Processing Systematization and Analysis). The definition of the Scopy object model for OTP structure is introduced and thhe development of an OTP structure modelling system is explained. In ScoPy, entities observed in cooperative design tasks are addressed in terms of their appropriate location in the space expanded by the organization, task and time. Based on ScoPy and its object model, a computer support system for OTP structure modelling was developed. The system, named DemoS³, accepts fragmentary design records, constructs the OTP structure by relating entities in the fragments, and provides users with a graphical representation.

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