This short paper briefly summarizes some key events in the history of the speed-up of railways. Some of the factors inhibiting speed-up of the railway as a system are reviewed: safety, passenger comfort, economics and environmental performance. Finally, some speculations are made on the future of railway speed-up.

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A new method for improving riding comfort by reducing vertical flexural vibrations in railway car bodies using piezoelectric elements is studied in this paper. Piezoelectric elements are attached on the car body in order to convert vibration energy to electrical energy, which can be dissipated in a shunt circuit. Assuming the car body as an elastically supported Bernoulli-Euler beam, theoretical analysis and numerical simulations are carried out. The numerical results are supplemented by experiments on a 1:5 scale model of a Shinkansen vehicle. Both numerical and experimental results indicate that the method yields significant vibration suppression with only a small amount of added weight. Two types of shunt circuits; a single-mode circuit and a multi-mode circuit are studied.

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The purpose of this study is to reduce a mechanical heat load which is generated inside the on-board superconducting coil (SC-coil) for JR MAGLEV. The mechanical heat generation inside the SC-coil-installed inner vessel was investigated on the assumption that it is generated by the friction caused by the relative microscopic slips between the SC-coil and coil fasteners. SC-coil vibration tests and FEM analysis were performed to study the correlation between SC-coil vibration and mechanical loss (dynamic vibration analysis). A fretting wear test was performed at liquid-helium-cooled boundaries between structural components of the SC-coil (tribological study). The results of dynamic vibration analysis suggest that the frictional heat occurs in the surrounding area of the support columns in the rigid body vibration mode and in the areas where the greatest degree of bending is observed in the eigen-mode of SC-coil twisting which involves elastic deformation. In the tribological study, test results demonstrated a high possibility that the mechanical loss inside the SC-coil-installed inner vessel had occurred on the boundary between the epoxy-impregnated SC-coil and coil fasteners.

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The lateral mathematical model of a high speed vehicle system with 17 degrees of freedom is set up and the nonlinearities arising duo to suspension parameters and wheel/rail interactions are considered. The coupler traction force in tension and compression cases which is the function of vehicle speed and position in the trainset is also taken into account in the model. The critical speed at the Hopf bifurcation point on straight and circular curved tracks are studied by utilizing efficient numerical methods. The influence of track curve radius and superelevation on the critical speed is investigated.

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This study aims to analyze fundamental dynamical characteristics of a tilting railway vehicle using variable link mechanism for compensating both lateral acceleration that passengers feel and wheel load imbalance between inner and outer rails. Theoretical analysis is conducted to find “Perfect Tilting Condition” that is a geometric parameter set of link mechanism that can provide both zero lateral acceleration and zero wheel load imbalance simultaneously. This perfect tilting condition can be realized by changing the variable length of link mechanism so that this tilting control system is a kind of semi-active control. To change the length of link mechanism on curved section, optimal control theory is applied to the vehicle body tilting system with a newly developed variable link mechanism. From computer simulation and experiment using a scale model, it is clarified that the proposed tilting system is effective to suppress both over-centrifugal acceleration and wheel load imbalance.

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Wheels of the railway vehicle play the important role for driving train through wheel-rail interaction. Especially wheel profile is one of the most important design factors to rule the running stability and safety of train. Accordingly maintenance of wheel like wheel profile control is also very important for securing safety and stability of train operation. This study presents the wheel wear measurement results of Saemaeul running on the conventional line. The train set included three different cars which have different shape of wheel profile including KNR profile currently used in Saemaeul. Train set was operated on Seoul-Pusan line with fixed train set formation for commercial service. Wheel wear measurements were performed periodically. We can find the influence of wheel profile on the wheel wear of the train running on the conventional line through the measurement results.

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Controlling the friction between wheel and rail is direct and very effective measures to improve the curving performances of bogie trucks, because the curving performances of bogie truck depend much on friction characteristics. Authors have proposed a method, “friction control”, which utilizes friction modifier (KELTRACK^TM HPF) with onboard spraying system. With the method, not only friction coefficient, but also friction characteristics are able to be controlled as expected. In this paper, results of fundamental experiments are reported which play an important role to realize the new method.

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Authors made an experimental event recorder, which can record not only the behavior of a train, but also accurately identify the site of the track where wheel slip and spin occur. The recorder was installed on a JR Ltd Express electric motive unite operated on conventional lines. They analyzed the date piled up in the recorder, and found several wayside factors which cause the wheel skiddings. The wheel skid occurrence rate par a 1000km train running distance was discussed under various weather conditions. Moreover, the results of the investigation were also discussed on the wheel skid occurrence rate in a snow bound area and the relationship between a snow weather condition and wheel skid occurrence rate.

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In order to enhance the speed of wheel slip prevention control for railway vehicles, modeling of adhesion characteristics after saturation of adhesion force, which had hitherto not been performed with trains, was performed via a beam model. The behavior of adhesive force between the wheel and rail in a wet condition was examined with a brake performance test stand for an actual vehicle. Results of comparing the model and test values indicated that the beam model represented test values well.

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In the present paper, the press fitting of railway wheels is studied with the aim of defining the mechanical and physical parameters to be adopted in order to reduce as much as possible the damaging of both wheel and axle during repeated press fitting and wheel removals. The study has been performed in a theoretical way, through a new multi objective optimisation method based on finite elements analyses. The FEM model has been experimentally validated. Referring to an actual case, the parameters that influences the press fitting process have been determined. The parameters influence was related not only to the mechanical stresses into the structures of wheel and axle respectively, but also to the robustness of the design (sensitivity to the machining tolerances and to friction coefficient variation at the press fit surfaces). Some optimal solutions have been determined and compared (in terms of performances) with an actual production one.

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The purpose of this paper is to demonstrate a new method developed to predict track wayside noise levels resulting from the passage of high-speed trains. The method calculates noise levels based on data acquired by the sound intensity method developed by the Central Japan Railway Company. This measurement method allows one to identify each sound source and its characteristics as well as identify how much each source contributes to the overall resulting noise level. Structure borne noise and multiple reflected noise between train car bodies and noise barriers are also studied. As a result of this study, a prediction method was created which can calculate and predict noise levels resulting from such various factors as structure, train type, train speed and noise barrier. Noise levels predicted during this study agreed well with those actually measured under various conditions, thus indicating the prediction method model resulting from the study is a useful tool to verify noise levels occurring at receiver positions. Furthermore, it can also verify in advance how much effect noise barriers or train source noise level reduction devices would have on noise reduction.

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To improve the efficiency of the linear induction motors (LIMs) for transportation, the compensation of end effect for LIM with the restriction of length and the long LIM with small end effect essentially are discussed respectively. Based on the proposed concept, the compensation method of the magnet rotator type and AC coil type of compensators are developed respectively. The utility is not yet confirmed. As for the long LIM with length of 10m, the analysis shows that the efficiencies are about 85% at 40km/h and above 90% at 360km/h respectively.

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Train headway models are established by analyzing the operation of the Transrapid Super-speed Maglev System (TSMS). The variation in the minimum allowable headway for trains of different speeds and consists is studied under various operational constraints. A potential Beijing-Shanghai Maglev line is used as an illustration to undertake capacity analyses with the model and methods. The example shows that the headway models for analyzing the carrying capacity of Maglev systems are very useful for the configurational design of this new transport system.

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Trains are often forced to decelerate or stop between stations on commuter lines due to the delay of the preceding train. If a train stops between stations, both the travel time and the interval between trains will increase. This situation has an adverse effect on energy consumption. To solve this problem, we propose a new train control method based on the prediction of train movement and data communications between railway sub-systems. Computer simulations are carried out to verify the effect of the proposed method. As a result, it has been proved that the new method reduces the train stopping time between stations and the electric energy consumption at substations.

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A decentralized interlocking system is proposed that assigns a unit to each track circuit and wires the units according to the track topology to achieve the function required of the entire system. The functions of each unit are represented by monotonic logic functions. The units are characterized in that they themselves can accomplish fail-safe error characteristics. The system consists of safety-related and non-safety related functional parts. The control requirements of signal aspects and switches are assigned to the non-safety-related parts, and the safety-related parts perform safety confirmation processing to judge whether or not the requirements are acceptable. This separation and the introduction of duality conversion help to achieve the safety confirmation desired of the interlocking system by the monotonic logic functions.

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In the age of traction system made of inverter and ac traction motors, distributed traction system with pure electric brake of regenerative mode has been recognised very advantageous. This paper proposes a new system as the lowest life-cycle cost system for high performance rapid transit, a new architecture and optimum parameters of power feeding system, and a new running method of trains. In Japan, these components of this proposal, i.e. pure electric brake and various countermeasures of reducing loss of regeneration have been already popular but not as yet the new running method for better utilisation of the equipment and for lower life-cycle cost. One example of what are proposed in this paper will be made as Tsukuba Express, which is under construction as the most modern commuter railway in Greater Tokyo area.

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In this study, the authors discuss methods to assess the future/actual damage to RC structures by using numerical simulations and vibration measurements. First, the applicability of the Applied Element Method (AEM) is examined as an assessment tool for the seismic performance of RC structures with/without retrofit. Cyclic loading tests and seismic response of RC structures are simulated. Next, a method to improve the accuracy of vibration diagnoses of earthquake damaged RC structures is discussed by using damage assessment criteria calculated with the AEM. The AEM could simulate the damage behavior of RC columns, jacketed RC columns and an actual railway viaduct. The change of natural frequencies due to damage to RC columns and an actual railway viaduct with steel jacket were also correctly estimated. Seismic performance check of structures and development of assessment criteria for damage inspection can be effectively done by the AEM.

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In deep-hole electrical discharge machining, the electrode jump height and hence the movement of the machining debris inside the side gap affect the wall concavity of the machined holes. In this study, the dielectric fluid flow and the debris distribution in the machining gap caused by electrode jump is analyzed to understand the wall concavity phenomenon of the holes using a computational fluid dynamics (CFD) simulation program. Fluid flow and debris-fluid interaction under low and high electrode jumps are examined and compared. The accuracy of the predictions obtained by the numerical calculation is assessed through comparisons with experimental data.

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The present paper describes a fundamental study on structural bending design to reduce noise using a new evolutionary population-based heuristic algorithm called the particle swarm optimization algorithm (PSOA). The particle swarm optimization algorithm is a parallel evolutionary computation technique proposed by Kennedy and Eberhart in 1995. This algorithm is based on the social behavior models for bird flocking, fish schooling and other models investigated by zoologists. Optimal structural design problems to reduce noise are highly nonlinear, so that most conventional methods are difficult to apply. The present paper investigates the applicability of PSOA to such problems. Optimal bending design of a vibrating plate using PSOA is performed in order to minimize noise radiation. PSOA can be effectively applied to such nonlinear acoustic radiation optimization.

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This paper is concerned with gas leakage fault detection of a pneumatic pipe system using a neural network filter. In modern plants, the ability to detect and identify gas leakage faults is becoming increasingly important. The main difficulty to detect gas leakage faults by sound signals lies in that the practical plants are usually very noisy. In this research, neural networks are used as nonlinear filters to eliminate noise and raise the signal noise ratio of the sound signal. Neural networks have a self-learning ability. This ability can be utilized to build a self-adaptive nonlinear filter. By learning from practical samples of noise and adjusting coefficients of connection weights of neural networks, a neural network filter can predict the future sample values of noise based on present and previous sample values. The predicted error between predicted values and practical ones constitutes output of the filter. If the predicted error is zero, then there is no leakage. If the predicted error is greater than a certain value, then there is a leakage fault. Through application to practical pneumatic systems, it is verified that nonlinear filters with neural networks was effective in gas leakage detection from noise background.

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In surgical robots, compact manipulators with multi-degree-of-freedom (DOF) are essential owing to a small work volume in the patient body. Conventional single-DOF actuators such as electromagnetic motors require a multiple number of actuators to generate multi-DOF motion, which in turn results in bulky mechanism combined with transmission device. Our previous work has developed a compact ultrasonic motor capable of generating a multi-DOF rotation of a spherical rotor utilizing three natural vibration modes of a bar-shaped stator. The present study designs and builds a novel multi-DOF master-slave system for laparoscopic surgical procedures, using a single ultrasonic actuator. The system consists of surgical forceps on multi-DOF wrist with joystick controller. Experimental results have confirmed high responsiveness and precise position control of the master-slave system.

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In this study, we propose a time optimal control scheme for kinematically redundant manipulators to track a predefined geometric path, subject to joint torque limits. The scheme can make full use of redundancy to increase the path-tracking velocity, and the time optimal trajectory planning problem is solved by using the phase-plane analysis and the linear programming technique. Computer simulation is also executed on a three-link planar rotary manipulator to show that, 1) the redundancy of the manipulator is fully used to increase the path-tracking velocity, and 2) redundant joints plus one more joint use their bound values of torque all the time while the time optimal path-tracking task is performed.

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The conventional sliding mode control motion has two phases, i.e., the reaching phase and the sliding phase. However, the invariance of the sliding mode control only applies to the sliding phase on the sliding surface. In the reaching phase, the switching control is applied to provide the robustness but there usually exists chattering. The conventional continuous approximation method can alleviate chattering but spoil the robustness. In this paper, a sliding mode control with global invariance is studied to solve the above problem. On the other hand, velocity sensors are often omitted to reduce the cost and reject measuring noise. In this paper, a Variable-Structure Model Following Control with output-feedback is proposed to solve tracking problems with modelling uncertainties and external disturbances.

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In this paper, we propose a new type of Autonomous Transfer Machine (ATM) by making use of pneumatic actuators such as pneumatic cylinders and bellows actuators. In the lifting part, the lifting arm which is constructed with a cylinder is rotated by antagonized bellows actuators. Moreover, the support part that a user leans on is supported by antagonized bellows actuators. Since the bellows actuator has a force sensing ability that acts both a force sensor and an actuator, external force that the user leans on the supporter can be estimated. In the standing-up motion, the support part is controlled by both the inclination of the support part and the force difference between holding force and supporting force. Therefore, the lifting trajectory of the supporter can be realized by the posture of the user. In this paper, we clear the effectiveness of the ATM with the standing-up motion from experimental results.

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A compliant mechanism is a mechanism that produces its motion by the flexibility of some or all of its members when the input forces are applied. Because of its mobility resulted from flexibility, it is difficult to expect the configuration in prioi. In this work, the design method of a compliant mechanism with the specified geometrical advantage is proposed to control the motion. The multiobjective optimization problem is formulated to minimize the deviation of the specified geometrical advantage and structural compliance of a mechanism and topology optimization is applied to determine the configuration of a mechanism. The results of example problems including a displacement converter design and a gripper design are compared with a multi-criteria model and show that the design of an accurate compliant mechanism with specified geometrical advantage can be obtained.

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Attitude synchronization is a key technology in the capture of tumbling satellites, and accurate estimation of the inertia ratio of tumbling satellites is an important function to synchronize the attitude of the chaser satellite with that of the tumbling satellite. This paper proposes a new control scheme, smooth reference model adaptive sliding mode control, or SRMASMC, for attitude tracking maneuvers. An adaptive law is introduced to accurately estimate the inertia ratio of the tumbling satellite, and a smooth reference model is employed to reduce the control torque at the beginning of the tracking maneuver. The attitude tracking performance of SRMASMC is evaluated numerically and compared with that of eigenaxis rotational maneuver control and sliding mode control. The results reveal that SRMASMC offers superior performance to these methods under the conditions examined.

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The motion cue performed by a motion simulator is restrained by the workspace of the simulator structure. A typical reasoning is then to build a large motion simulator unless it is for entertainment, which involves in small simulators. This study proposes a novel approach to designing the washout filter of the motion control of a six degree-of-freedom motion simulator for entertainment purposes. Using information obtained from the inverse kinematics of the simulator, the workspace boundary, detected in real-time, is fed into the washout filter as a reference for the motion planning. The main focus of this approach is to make the motion cue feasible for use in a simulator with a restricted workspace, while ensuring the robustness of the driving system. In this paper, different indices are established to specify the performance of the motion cue. A classical linear washout filter was implemented and compared with the proposed washout filter using the performance indices to demonstrate the benefits of the latter.

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In this study, the sensorless control algorithm is applied to improve the position control accuracy of the output plunger of a switching solenoid. The main purpose of this study is the attempt to develop a fluid-technical proportional valve with simplest construction and lowest cost. Since the switching solenoid is not equipped with a position sensor and consequently no closed-loop control theory can be applied, the accuracy of the position control of the output plunger becomes a most critical question. Therefore, a modified open-loop controller using the sensorless control algorithm is proposed. The basic idea is the utilization of the sensorless control algorithm to estimate the steady-state position of the plunger. Then, this estimated position is fedback to the controller and the input current during the steady-state response is real-time adjusted according to the error signal. Finally, a series of experiments are carried out and the results show that the proposed modified open-loop controller improves significantly the steady-state accuracy of the plunger position and provides an alternative approach to design unconventional proportional valves.

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We propose an interconnected suspension mechanism that is applicable to rough terrain mobile robots for construction sites. All wheels can follow on uneven ground by moving mutually with an interconnected suspension mechanism. And, it is possible to control the posture of the robot simply using the mechanism. In this paper, the structural and mechanical characteristics of the mechanism are discussed and the ground contact loads of wheels are analyzed. It was confirmed the mechanism has enough ability for moving on an uneven floor and posture control through experiments with an experimental rough terrain moving robot.

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An important aspect of an automated highway system design is the synthesis of an automated vehicle following system. Associated with automated vehicle following system is the problem of the stability of a string of vehicle, i.e., the problem of spacing error propagation, and in some cases, amplification upstream from one vehicle to another, due to some disturbance at the head of the string. In this paper, the novel method to determine the stability of a string of vehicle is established based on the vector Liapunov method. Based on the new results for the stability of string of vehicle, the controller is constructed by sliding mode control method. The stability domain of the controller parameters of the string of vehicles is enlarged.

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This paper proposes a new Electro-Magnetic-Suspension (EMS) system, which has the ability of self-banking in curve section. This new EMS system can tilt automatically corresponding to the magnitude of the centrifugal force. Four hybrid-magnets (HMs) ─ a combination of permanent and electro-magnets ─ are used to guide and suspend a vehicle simultaneously in a manner different from that of a conventional EMS system, which acquires the necessary force from a guidance system while running in a tight curve. The Nearly-Zero-Power control method is applied to minimize energy consumption of the HMs. Five degrees of freedom are considered during the simulation and the experiment. The results of the simulation and the experiment demonstrate that this new EMS system has the ability to tilt automatically corresponding to the magnitude of the centrifugal force and nullify the constant disturbance forces applied in five directions using only the attractive forces of the permanent magnets (PMs) in the HMs and the earth's gravity.

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In this paper, a vibration suppression scheme of an axially moving steel strip in the zinc galvanizing line is investigated. The moving steel strip is modeled as a moving beam, in which the tension applied to the strip is a spatiotemporally varying function. The transverse vibration of the strip is controlled by a hydraulic touch-roll actuator at the right boundary. The mathematical model of the system, which consists of a hyperbolic partial differential equation describing the dynamics of the moving beam and an ordinary differential equation describing the actuator dynamics, is derived by using the Hamilton's principle for the systems of changing mass. The Lyapunov method is employed to design a boundary control law for ensuring the vibration reduction of the system in the presence of a spatiotemporally varying tension. The exponential stability of the closed loop system under the boundary control is proved through the use of invariance principle and semigroup theory. Simulation results verify the effectiveness of the boundary control law proposed.

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In this research, a platform is built to accomplish a series of experiments to control the Antilock Brake System (ABS). A commercial ABS module controlled by a controller is installed and tested on the platform. The vehicle and tire models are deduced and simulated by a personal computer for real time control. An adaptive PID-type fuzzy control scheme is used. Two on-off conversion methods: pulse width modulation (PWM) and conditional on-off, are used to control the solenoid valves in the ABS module. With the pressure signal feedbacks in the caliper, vehicle dynamics and wheel speeds are computed during braking. Road surface conditions, vehicle weight and control schemes are varied in the experiments to study braking properties.

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This paper discusses the robust stability of Takagi-Sugeno (TS) fuzzy model based control systems. First, it is pointed out that the complex nonlinear control systems with uncertain parameters can be represented as the TS-fuzzy-model-based control systems with both elemental parametric uncertainties and norm-bounded approximation error. Next, a sufficient condition is proposed in terms of linear matrix inequalities (LMIs) for ensuring that the TS-fuzzy-model-based control systems with both elemental parametric uncertainties and norm-bounded approximation error are robustly stable. Some examples are given to show that the proposed sufficient LMI condition may obtain less conservative results than the existing ones reported recently, owing to the proposed sufficient condition taking the elemental information of the parametric uncertain matrices into consideration.

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In this paper, we consider the tracking control problem of a nonholonomic mobile robot in the presence of bounded disturbances. We propose a method for modifying the control law of Jiang et al. (1997) so that the resulting control law guarantees global stability and the tracking error converges to a neighborhood about zero that can be made arbitrary small in the presence of disturbances. Further, we show that the tracking error converge to zero in the absence of disturbances. A numerical example is provided to show effectiveness of the method.

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In this paper, the problem of the regional eigenvalue-clustering robustness analysis for linear discrete time-delay systems with both structured (elemental) and unstructured (norm-bounded) parameter uncertainties is investigated. Under the assumption that all the eigenvalues of a linear nominal discrete time-delay system lie within a specified region, a new sufficient condition is proposed to preserve the assumed property when both the structured (elemental) and the unstructured (norm-bounded) parameter uncertainties are added into the linear nominal discrete time-delay system. No restriction is imposed on the shapes of the specified region. When all the eigenvalues are just required to locate inside the unit circle, the proposed criterion will become the robust stability criterion. For the case that the linear discrete time-delay system only subjects to structured (elemental) parameter uncertainties, by two illustrative examples, the presented sufficient condition is shown to be less conservative than the existing one reported recently in the literature.

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There is a growing tendency to use the Internet as the transmission medium of the telerobotic system since the Internet is inexpensive and available all over the world. However, the bilateral real-time teleroperation can be unstable due to the random time delays of the Internet. The `Event based teleoperation' is one of the fine approaches to overcome the random time delays. Since the event based control uses a non-time action reference, the stability and response performance of the system are affected by the time which an event is held for. This study introduces the variable holding time to secure stability and response performance at once. The proper holding time for each event is obtained depending on the characteristics of the task through the fuzzy logic. The proposed control scheme was implemented on a robot arm over the Internet to show its effectiveness.

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This paper proposes a method that minimizes the energy consumption in the locomotion of a biped robot. A real-coded genetic algorithm is employed in order to search for the optimal locomotion pattern, and at the same time the optimal locations of the mass centers of the links that compose the biped robot. Since many of the essential characteristics of the human walking motion can be captured with a seven-link planar biped walking in the saggital plane, a 6-DOF biped robot that consists of seven links is used as the model used in the work. For trajectories of the robot in a single stride, fourth-order polynomials are used as their basis functions to approximate the locomotion gait. The coefficients of the polynomials are defined as design variables. For the optimal locations of the mass centers of the links, three variables are added to the design variables under the assumption that the left and right legs are identical. Simulations were performed to compare locomotion trajectories obtained with the genetic algorithm and the one obtained with the gravity-compensated inverted pendulum mode (GCIPM). They show that the proposed trajectory with the optimized mass centers significantly reduces the energy consumption, indicating that the proposed optimized method is a valuable tool in the design of biped robots.

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In the field of computer vision, it is a complex and demanding much task to detect and to track moving objects from a moving observer. However, in this paper a new scheme for a mobile robot to track and capture a moving object using images of a camera is proposed. The system consists of the following modules: data acquisition, feature extraction and visual tracking, and trajectory generation. And a single camera is used as visual sensors to capture image sequences of a moving object. The moving object is assumed to be a point-object and projected onto an image plane to form a geometrical constraint equation that provides position data of the object based on the kinematics of the active camera. Uncertainties in the position estimation caused by the point-object assumption are compensated using the Kalman filter. To generate the shortest time trajectory to capture the moving object, the linear and angular velocities are estimated and utilized. The experimental results of tracking and capturing of the target object with the mobile robot are presented.

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The tactile wear (“tezure” in Japanese) is an abrasion phenomenon of material surfaces caused by the contact of human hand over a long period of time. Though this phenomenon has been the focus of various articles, an extensive study with regard to the wear characteristics is of a profound importance. To date, we have several remarkable examples such as the statue of Pindola Bharadvaja (Buddhist) and the St. Peter statue (Christian). Followers of the respective religions who are deeply attached and rooted have been touching the statues as part of their rituals for many generations over centuries. In this study, an attempt is done to verify the friction and wear characteristics of various soft metals with contact of human finger. The results of our experiments show that the friction coefficient upon the contact of the human finger and pure copper are very high and thus proving tactile wear of soft metals can be generated easily.

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Universal joints, which transmit torque through the balls guided in such a manner that they always lie in the plane bisecting the angle between the driving-shaft and driven-shaft, are called ball-type constant-velocity joints. The authors presented papers on the analysis of this type of universal joint based on statics neglecting the friction force between their components. To obtain more precise estimations of the internal forces and the moments, it appears to be important to evaluate the effect of the friction between the parts. Furthermore, grasping the relative motions of the parts, such as rolling of the balls on the tracks, is beyond the scope of static analysis. In this study, the authors analyze the motions of each part based on dynamics, taking account of the friction between the parts. The analysis results in simultaneous differential equations, which can be solved numerically using an electronic computer.

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Ball-type constant-velocity joints are extremely important components of the front wheel drive systems of cars. However the method to analyze the characteristics of this type of joint has not been established. The authors previously presented papers on the analysis based on statics, in that no frictional forces inside the joints were taken into account. Recently the authors presented advanced analysis based on dynamics, in which the frictional forces were considered. In this paper the numerical analyses of a ball fixed joint (BJ) and a double offset joint (DOJ) used for the front wheel drive of a car are carried out using the simultaneous equations induced in the former analysis and the simultaneous differential equations induced in the latter analysis. Contact forces acting inside DOJ are measured using piezoelectric sensors. The results of the numerical analyses based on dynamics show better coincidence with the measured value than those based on statics.

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Small oil particles generated from lubricant for ball bearings in HDDs sometimes cause fatal problems such as head crashes. A labyrinth seal is often used to prevent oil particles from scattering onto the disk surfaces. In this paper, the sealing performance of labyrinth seals for small oil particles is investigated numerically and experimentally. Two types of labyrinth seal are considered, one a straight-type and the other a bent-type seal. It was found that the sealing capability of the labyrinth seal is generated by the centrifugal force exerted on oil particles due to disk rotation when they pass through the seal gap.

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To respond to rapidly changing and diversifying customers' requirements, an industrial design support system for eyeglass frames which allows the customer to participate in the industrial design process was developed. This system is based on the Interactive Evolutionary Computing (IEC) technique so that a customer can interact with the system to express his or her Kansei requirements through images. The design of an eyeglass frame cannot be determined in isolation but rather must be determined by considering its appearance on the customer. In the developed system, the user evaluates each sample suggested by the system and narrows down the candidate gradually. Its usefulness was demonstrated by operational experiments and questionnaires.

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In the design and usability of many engineering products, the layout design of component plays an important role. Recently, engineering artifacts are becoming increasingly complicated. The simulated annealing method has been applied effectively to the layout and packing problems of wafer. The main characteristics of simulated annealing method is that an optimum can be obtained from the many local optimums by controlling the temperature and introducing the statistic flickering. The objective of this study is to suggest a method to apply the simulated annealing method to the three dimensional layout design of submergible boat which has multiple constraint conditions and evaluation criteria. The results of this study revealed that; 1) As the constraint conditions for three dimensional layout design, the relational constraint condition and the layout constraint condition were defined. 2) The total evaluation criteria and the individual evaluation criteria were included in cost function. 3) A method to generate and to change the layout state for three dimensional layout design was suggested. 4) Three dimensional LAYout Design Optimization Program (LAYDOP ver.1) for an ocean space submergible boat was developed by the suggested method and verified that the suggested method had validity.

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