To improve riding comfort of driver's seat, we have proposed active suspension system for heavy duty truck. In this study, the control mechanism of the active seat suspension was designed for a small vehicle like community car with using coefficient diagram feedback control method. The operability improvement for senior citizen, vibration isolation for baby and riding comfort improvement in the unpaved road can be expected. In order to examine the effectiveness of the system, experiments were performed for some road surface conditions.

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We have proposed a magnetic levitation control system for a sheet steel and confirmed the realization by the digital control experiment. However, the case in which only the levitation control is applied for the steel plate, it has no horizontal restraining force in the traveling. Then, the electromagnetic actuators are installed in order to control the horizontal position of the levitated sheet steel. The electromagnetic attractive control forces of the actuators are given for the faced two edges of the levitated sheet steel from horizontal direction. In this paper, the suppression effect of elastic vibration of the levitated sheet steel in the horizontal noncontact positioning was reported. The results of experiment showed that the elastic vibration of the sheet steel could be sufficiently suppressed and effective could be confirmed to the stabilization of magnetic levitation when the steel plate was transported.

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There is a problem of which the elastic vibration of a thin steel plate is excited by the nonlinearity of the electromagnetic force and the disturbance to the control signal. In this study, we used the sliding mode control method in which the application was easy for the nonlinear magnetic levitation model. The modeling of the sheet steel were based on 1DOF system and continuous system. The superiority of the sliding mode control application was examined experimentally on the robustness for disturbance to the control signal and the parameter variation.

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In this study, examination on elastic vibration of a thin steel plate under magnetic field by using permanent magnets was carried out. The attractive force of the permanent magnets is analyzed by using the finite element method and the elastic vibration of the steel plate was calculated by the finite difference method. To verify usefulness of the permanent magnet system, experiments were performed for an elastic steel beam and an aluminum beam. As a result, it was confirmed that the permanent magnets could increase the damping factor of elastic vibration of the steel plate.

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In a processing facility, the plate usually travels at a velocity of more than 10m/s. When a long steel plate travels at high speed, rollers are usually used as supporters. However, when rollers are used, deterioration caused by cracks in the process of coating or gilding is possible. We have proposed noncontact guide by using electromagnetic attractive force for a traveling steel belt. In this study, modeling for the system was presented. To verify the usefulness of the modeling, control experiment and simulation were performed.

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Impact tension was applied to a PMMA (polymethylmethacrylate) strip specimen with a notch. An inclined notch was introduced by milling specimens before the experiments. The fracture strains ε_<nf> and ε_<sf> were measured near the notch root and at the smooth portion, respectively. The strain concentration factor defined by the ratio K_f=ε_<nf>/ε_<sf> was a constant to the inclination angle of notch, θ The factor K_e of the short specimen in the elastic region was larger than that of the long one. The impact strength of the strip with a notch could be estimated by the strain rate near the notch root.

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Because of their high specific strength and stiffness, fiber-reinforced plastics is used as structural members in various fields, and hence analysis of thin laminated structures is important. Post buckling behaviors of laminated plates under uniaxial compression have been discussed by many researchers. However, little research has been performed on the post buckling behavior of laminated curved plates. In this paper, the stability condition of CFRP angle-ply laminated curved plates under uniaxial compression and which are simply supported along four edges is determined using Galerkin's method. The post buckling behavior is proven analytically, and the effects of various factors, such as the dimension of the curved plate, deflection pattern, average axial shortening and amplitudes of initial imperfections, are clarified.

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Experiments were performed to study the energy absorption efficiency of axially crushed aluminum circular tube. Axisymmetric buckling has the advantage in efficiency of energy absorption. Then, axisymmetric buckling is induced by using the jig, which restricts the radial inside. It was shown that the friction between the jig and the tube as well as the trough shape of the load displacement is available to improve the energy absorption efficiency.

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Recently the compatibility of crash safety and lightweight is one of the most important technical subjects in body design. It is considered that the resistant strength has to reach a balanced level between the energy absorption structures and the deformation control structures for crash safety design. Although the CAE technology has been widely and successfully used to get the characteristic values in the crash safety evaluation, it is necessary to accurately estimate the ultimate strength of the structural member of car in the initial stage of the design for time saving. In this paper, the post-buckling behavior of the structural member is considered and an analysis method is developed. By assuming the displacement during the buckling and applying Galerkin method, the ultimate strength is obtained and is in good agreement with the result of FEM.

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Carbon fiber reinforced carbon matrix (C/C) composites have recently been studied and developed for structural applications in the field of aerospace and under high temperature environment. However, C/C composites have low impact strength. Therefore, it's important to evaluate impact damage properties and impact strength in C/C composites. In this study, the estimating methods for impact damage are the determination by the relationship between the impact load and displacement in a drop weight impact test, and the signals of impact bar are analyzed with wavelet transform for evaluating the impact damage and modes in C/C composites. The measured impact load is reduced higher mode of vibration by wavelet analysis. As a result, the impact damage in bar of C/C composites that a type of laminate 0°/90° can be determined with some measuring methods.

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This paper describes the influence of exciting position on the coupling vibration of the end plates and the sound field into a cylindrical enclosure. The coupled vibration analysis is mainly carried out for the circumferetial shifts of exciting position. The analytical result are expressed as distributions of the sound pressure level within the cylindrical cavity, and the relation between the contribution of dominant modes to the distributions and exciting position is examined. As a result, it is evident that the coupling depends on the contribution of dominant modes which change a degree to react upon each other with exciting position.

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Role of engine valve spring is to rightly turn intake air and exhaust valve for engine for automobile in cam profile way on and off. Surging phenomenon of valve spring becomes a problem with speedup of the engine as jump of valve and cause of bounce. However, analysis case is little for the dynamic behavior, since it is complicated. In this study, the model which measured the actual valve spring is used. It is recognized that the form of the seat end of the spring changes the stress state in a valve spring. Static, dynamic behavior and stress state of valve spring are examined using the finite element method.

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The size of rigid airship model used for experiment is 1/300 scale one of the Graph Zeppelin and its overall length and maximum diameter of the section are 0.8m and 0.1m, respectively. The experiment is carried out changing yawing angle from 0 to ±90°and in Reynolds numbers 5.3×(10)^5 and 1.1×(10)^6. Effects of the yawing angle and Reynolds number on drag, side force and yawing moment are examined.

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Evaluation of calculation accuracy is always needed when performing numerical computation. For this reason, the accuracy will be estimated by comparison with an analytical solution or experimental results. In CFD, the Navier-Stokes equation can be solved by the finite-difference methods. However, it is difficult to investigate the reliability and accuracy of the calculation results, since general flows do not an analytical solution. Moreover many guidelines exist from experience simulation about the computational domain size and other parameters. This research provides guidelines that can be used as these standards for the flow around an airfoil. First, a result calculated by a singularity method of distributing vortex sheet on an airfoil surface and a finite difference method are compared with an exact solution solved by the conformal mapping method about a potential flow, and the accuracies are checked. Finally, dealing with an actual problem of the viscous flow, the limit of the accuracy is grasped by computing the Navier-Stokes equation

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The research on the flow around a L-type cross section bodies was carried out by an experiment and numerical simulation. The drag and lift of the bodies were measured in the range Reynolds number Re=1.5×(10)^4 to 6.5×(10)^4 in a uniform flow. The effects of the body position and Reynolds number on drag and lift coefficient were considered. The measurement of the drag and lift were carried out a direct method using the strain gauge load cells. A body of L type cross section with equal sides of one side 35mm, 3mm thickness was used as a test piece. As the result, the drag and lift coefficients hardly are affected in Reynolds number. Those coefficients are dominated by the position of the body for the flow. The drag coefficient shows the maximum value at the position in which projected area becomes a maximum. The life coefficient shows the maximum value at the position in which projected area becomes a minimum. The numerical simulation of the flow around a body was carried out by using CFD 2000 developed by Adaptive Research Co, . The drag and lift coefficients were calculated at various positions of the test piece and Reynolds numbers. Also, the velocity vector, pressure distribution, the drag and lift coefficients, and flow pattern around a body were obtained, and they were compared with experimental ones.

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In this study, The three dimensional flow past a sphere and a rotating sphere with smooth surface in a uniform stream is calculated by the finite element method with the fractional step method and the balancing tensor difusivity method. At the high Reynolds number Re&ge;1.0×(10)^4,we analyze that flow using Large Eddy Simulation. Turbulent model is the Smagorinsky model. As a result, the agreement with experiment and the flow visualization was reasonable up to reynolds number 500.

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On competitive free style swimming, hand paddle generates main thrust force. Configurations of hand paddles for the maximal thrust force were investigated by measuring drag and lift forces. As results, the distinguished difference of the thrust force was not obtained by the hand configurations. However small spacing between fingers was effective for the substantial increase of hand area leading to the escalation of thrust force.

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Motorcycles are more lightweight than cars, unstable because of two wheels, and tends to be influenced by oncoming flow. In this experiment, the aerodynamic characteristics of two 1/5-scale naked motorcycle models are measured using a low-speed wind tunnel and a six component force balance. The models are basically same, but one has the cowling and the other doesn't. The wake is visualizied using wake survey, and the effect of the cowling is investigated from the view points of the C_D value and the wake structure. It was obtained that the model equipped with the cowling has a lower C_D than the model without the cowling. The results of the wake survey show that there is small turbulence and the generation of vortices is surpressed in the former case. It is concluded that the cowling is effective to arrange the flow and decrease the aerodynamic drag.

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The low-pressure axial flow fans with an outer ring, used for cooling automobile radiators, have a significantly large tip clearance between the ring tip and the fan shroud. It has been known that the turbulence of reverse flow, or leakage flow, which occurs at the tip clearance, greatly affects the performance and noise level. In order to improve the performance and noise level, the authors studied about the labyrinth seal which was used at the clearance. As a result, we discovered that it was possible to predict the performance by conventional theory when the labyrinth was stationary, and that the leakage rate decreased significantly even though the ring speed was much less than that of past research when the ring was rotated.

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In the flow around a circular cylinder, the sudden decrease in the drag force occurs at a high Reynolds number, but the same phenomenon occurs at a lower Reynolds number in the case where there exist grooves or roughness on the circular cylinder surface. In this paper, in order to make clear the flow characteristics around a circular cylinder with triangular grooves, drag coefficient, pressure distribution and Strouhal number were measured. Moreover the flow was analyzed by applying the RNG k-ε turbulent model and the surface flow pattern was investigated using oil-film technique. Consequently, it made clear that the drag coefficient of a circular cylinder with triangular grooves decreases about 20% compared with a circular cylinder with arc grooves.

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This paper describes the calculation of traction with spin by using the Johnson-Tevaarwerk's non-linear viscoelastic model as a rheological model and by estimating the sliding velocity within the contact ellipse. The effects of temperature and velocity on traction with spin are reported. Furthermore, a formula for evaluating a maximum traction coefficient easily is proposed.

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A noble ball-on-disk type EHL tester was built as a trial in order to study the traction characteristics under the steady state as well as the non-steady state conditions. Under the steady state conditions, the traction coefficient of the synthetic traction oil decreased with increasing temperature while it was little affected by change in contact pressure. This is probably because an EHL oil film behaved as a plastic solid. In addition, the influence of skew component and a kind of lubricant was studied. The experimental results were in good agreement with the previous reports.

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Traction characteristics under the non-steady state conditions were studied with a ball-on-disk type EHL tester, in which the experiments were conducted by moving the disk toward the rolling direction to the predetermined position. When giving the rapid change in the rolling speed of the disk under keeping the constant rolling speed of the ball, a delay of change in traction was appreciably observed.

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Small size of linear driving devices with high accuracy and high stiffness are require for miniaturization of machine tools such as a micro-lathe. This paper describes traction characteristics of the linear driving device with a slider built-in two PZT elements. From the experiments on the characteristics, it was clarified that stable movements of the slider are obtained under low viscosity oil lubrication and traction force more than 5(N) of the slider is generated under slider guide pressure more than 140(kPa).

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Control mechanism of traction drive CVT has been described. Steering effect at contact point is key issue for changing ratio. The mechanical feed back system is used to achieve good control system. To synchronize 4 power rollers is also important technology to get high torque capacity transmission. With this mechanism, ratio change will be completed within 0.3 second.

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A continuously variable transmission (CVT) will improve fuel economy of an internal combustion engine driveed automobile. At 1999 in Japan automobiles with half-troidaltype CVT were started to sale from NISSAN MOTRON-DRIVE was developed for front drive small automobiles and future Electric vehicles (EV)

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MOTRON-DRIVE developed the 3 K type CVT of wide range at speed ratio (∞-1). In this report, it is introduced to case that the CVT was designed to load into a FF car. The driving source of the FF car is used by induction motor instead of engine, and the deferential gear is situated between this motor and CVT. A size of CVT is 140 mm at the inner ring caliber and is 300 mm at the total length. The motor capacity is 22kW and velocity of revolution is 1500 rpm. In this case, total of deceleration ratio at the transmission is 1 and maximum speed of this vehicle is 150 km/h.

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Future planetary exploration missions will require rovers to travel wide range effectively and perform difficult tasks safely in rough terrain. The surface of the moon is covered by soft and slippery material called regolith. So the drive of rovers involve risk of stack, which makes it impossible to move forward by digging the soil with wheel rotating. A lot of conventional motion planning and control algorithms do not consider the physical characteristics of the rover and its environment, which limit their effectiveness in rough terrain. However the interaction between a wheel and the soil is one of the most important factors for considering the mobility of rovers. A lot of the mechanism remains unclear and the conclusive model of their interaction is not established. In this paper, the results of the foundamental experiments of a wheel drive on luna soil simulant are presented. The traction control as a stack avoidance method is also mentioned.

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This paper investigates the power split type differential planetary mechanism (SDM) that includes CVT and is possible to operate in high efficiency region. There are two regions indicating high efficiency in the coordinate, horizontal axis of which is ω_1/ω_3 and vertical axis ω_2/ω_3,where ω_3 is angular velocity of input shaft of planetary system, ω_1 and ω_2 are velocities of other two shafts of it. The paper shows planetary mechanism possible to set operating point in the high efficiency region. Using CVT as an apparatus to realize operation in high efficiency region, SDM having high efficiency can be obtained.

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When a strong earthquake occurs, many buildings are destroyed. For the inhabitants of such buildings, having sufficient time to take refuge is critical. This study presents the basic concept of a control system for stabilizing a plastic-deformed building by jetting out compressed gas while the inhabitants escape. This system features easy installation. Constant pressure gas is employed, and is controlled to jet or to stop jetting. In this study, the plastic-deformed building is modeled as a two-link inverted pendulum, and stabilized by only one thruster. The design of stabilizing controller is based on the sliding mode control theory. And the chattering of control input is suppressed by setting an insensitive zone. Then, numerical simulations and model experiments confirm the validity of the proposed control system.

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Most of non-rubber type isolation systems apply frictional force. One of the famous non-rubber type isolation systems is Friction Pendulum Bearing ( : FPB) system. When using friction pendulum system in the open air circumstances, some have pointed out that long term durability of the systems must have been taken into account and it might have been very difficult to maintain the friction coefficient. In this study, the behavior of the structure and the isolation systems in considering the dispersion of the friction coefficient of the each device and vertical load on the each device is examined during earthquake. In this report, the analytical models used the square structure, and these models are considered as rigid body models. The dispersion of the friction coefficient and vertical load is made to occur from the normal random number. The behavior of the structure and the isolation systems during the earthquake was stochastically investigated using a Monte Carlo method.

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"Wind force" is improved which people have used for long time ago. Recently, wind forces have been reconfirmed as important energy. There is wind energy conversion system which wind energy is efficiently changed into electric power. This system have been researched and developed. However, there are some problems in this system. This vibration which is generated in winds, earthquakes, and propeller rotation. May have the bad influence of storing up fatigue on the tower itself. In this research, it aims that safety of this system improves using dampers including masses, such as TMD (Tuned Mass Damper) and IMD (Impact Mass Damper) which is applied impact energy. We carried out analysis with simple model of wind energy conversion system during earthquakes and winds. The result of this analysis is reported in this paper.

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Recently, the number of earthquake isolation structure has been increased. The most of earthquake isolation structure is applied the rubber bearings. However, light-weight structures such as wooden houses were not applied the isolation device, because it is difficult to apply the rubber bearings, for example, the diameter of the rubber bearing narrows according to extension of the natural period of the rubber bearing, and the device can not support superstructure. In this study, the purpose is development about isolation system for light-weight houses. we propose that the structure is supported with the sliding rubber bearings and the sliders. In this paper, result of numerical analysis in this system was reported.

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Since earthquakes that are heavier than the assumed one have broken out in recent years, the conventional earthquake-resistant plans of plant piping are inadequacy and rational plans by flexible views are searched for recently. This paper describes about elastic-plastic response of a beam of SUS304. The experimental object used in this study has parallel two beams that have narrow parts. The seismic excitation tests by natural frequency were performed with several input levels. Damping ratio and natural frequency were shown by the function of response displacement and the simulation program was made. This simulation showed the tendency of experiments well. Improvement in the precision is a future subject.

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Under extreme seismic excitation, plastic deformation occurs in piping system. It is considered that the large damping effect causes with energy dissipation by the plastic deformation. In this study, a simplified method to calculate the damping effect and maximum seismic response of piping with plastic deformation was examined. The maximum response by this method resulted in appropriate simulations of the excitation tests of the piping models.

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In order to control vibration of adjacent buildings connected with control devices, this paper presents two methods for designing the semi active controller with a variable damping device. Semi active controller are applied to control the vibration of building structure. A semi active device is defined as a kind of passive element that has variable properties changed according to external maneuvers. And so we using Magnetorheological Fluids damper in the stead of a variable damping device. Simulation results demonstrate an availability and possibility of semi-active control.

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When the system is subjected to excess dynamic load, the response has hysteresis loop characteristic caused by plastic deformation. For nonstationary random excitation, the response is nonstationary random process. In this paper, mean square values of the response are obtained based on equivalent linearization method. Integral of mean square value with respect to time is defined as vibration response energy. It is concluded that vibration response energy decreases with the decrease of yield force and post yield stiffness.

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We have proposed an position control method for a two-joint manipulator with the second joint free under gravitational effect. The control objective is to swing the free link from the gravitational direction to the opposite position and then to stabilize the free link at the inverted position without feedback control. In this paper, the theoretical procedure for the realization of the control is provided. The averaged equation governing the motion of the free joint is derived by using the method of multiple scales. The bifurcation analysis for the equation shows the variation of the stable equilibrium states under changing the configuration of the actuated joint. Finally, experimental results confirm the validity of the proposed control method.

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This paper describes the rotational motion of a double pendulum to investigate the mechanism. The first pendulum, or the main pendulum is supported free to rotate at one end and at the other end the second pendulum is attached, that rotates at a certain speed with respect to the first one. As a result, the rotatinal motion of the double pendulum is good agreement with the result of limited power of the motor. The calculated results of initial conditions show the lowest speed and the area which is attracted to the limit cycle.

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The purposr of this study is to develop a procedure to attenuate self-excited sound. It is well known that when wind blows against the Helmholtz resonator, self-excited sound is generated at the frequency according to the geometrical shape of the throat and the body. The two cases of the self-excited sound generated by a uniform flow over the coupled resonators are enforced or attenuated each other due to the length of connectiong tube.

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This paper deals with impact vibrations in continuous system excited by periodic force with arbitrary functions. The analytical model is steady impact vibration in both ends supported beam having an attached mass, which collides elastically to symmetric faces. In order to analyze the main resonance subjected to excitation by displacement, the resulting vibrations are analyzed by applying the Fourier series method to this system. Following these theoretical analyses, numerical calculations are performed, and the resonance curves are made using the resulting vibrations. Effects of the stiffness of clamped spring, the amplitude of excitation and the attached mass ratio on the resonance cure are shown by numerical results. For verification of the analytical method, experiments are performed. The numerical results are in a fairly good agreement with the experimental ones.

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In this paper, we discuss an aerial posture control problem of a 2-link horizontal bar robot with nonzero initial angular momentum in order to realize an acrobatic motion of the horizontal bar. First, the equations of motion and the law of conservation of angular momentum are shown. Next, we derive a strict feedback system to be able to apply backstepping procedure by 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 backstepping procedure to the system. Finally, we present simulation results to validate the controller.

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In this research, two types of variable dampers using MR fluid were manufactured and their typical characteristics were compared experimentally. MR fluid can change the rheological characteristics under the applied magnetic field. They are adopted double-ended piston-rod and double cylinder type. The magnetic circuits was designed to focus magnetic flux lines using FEM, but they differ in the course of the magnetic circuit. The damping force of prototype MR dampers was experimentally measured under sinusoidal excitation at various amplitudes, frequencies, clearances of orifice and applied magnetic field strength. Experimental investigation shows that the maximum damping force of the type B damper is about eight times as large as that of the type A.

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