Oscillations in a rotor system with a radial clearance between the outer ring and the casing are investigated by experiments and numerical simulations. The mathematical model includes collision in the clearance. The following phenomena are found: (1)Various kinds of nonlinear resonance occur. (2)Self-excited oscillation of a forward whirling mode occurs in a wide range above the major critical speed. (3)Entrainment phenomena occur in the resonance ranges of nonlinear forced oscillations. In order to obtain a guideline to rotor design, the influence of bearing damping, rotor unbalance and static lateral force on the occurrence of the nonlinear resonances and self-excited oscillations are investigated.

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In magnetic disk drives, the increase of disk rotation speed has made the amplitudes of disk flutter larger. Flutter causes head-positioning errors. Therefore, it is important to predict the amount of head positioning error caused by disk flutter. We created an estimation method of the head-positioning error due to flutter from the disk flutter amplitude. We applied this method to 2 magnetic disk drives and checked its accuracy by comparing the estimated results with the analysis results of the head-positioning error signals. We proposed a design method of disk size and disk rotation speed using this estimation method.

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A simplified method is proposed to obtain eigenfrequencies and modes for an axisymmetric vibration of a pressurized tank of a rocket filled with liquid propellant. The purpose of this simplified method is to prepare a simplified analysis tool in the preliminary design phase and to use as a pilot analysis for the detailed analysis in the development phase. To this end, present method can treat fluid-structure interaction and can analyze the effects of tank pressurization. POGO prevention is a classical problem in design of a large liquid rocket such as the US Space Shuttle and the Japanese H II rocket. In particular, axisymmetric modes in longitudinal vibrations of the vehicle are important for POGO stability analysis because they have potential instability coupled with propulsion system dynamics. Consequently, proposed simplified method enables axisymmetric vibration analysis of shells of revolution using a FORTRAN 77 program, which has the following three capabilities; (1) Finite Strip Method (FSM) structural vibration analysis for a pressurized tank, (2) Boundary Element Method (BEM) sloshing vibration analysis for liquid propellant, (3) fluid-structure coupled vibration analysis. Structural vibration analysis on a hemispherical tank has verified accuracy of this simplified method, and also demonstrated the capability of this simplified method. Based on these demonstration analyses, the proposed method is judged to be an efficient structural vibration analysis method of a pressurized tank of a rocket filled with liquid propellant.

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Nowadays, in Northern Europe, Japan, and USA, many researches have been presented about S. F.T. (Submerged Floating Tunnel) adapting for coastal and Fjords traffic systems. But the natural frequency of S.F.T. is below a few Hz because of three types support conditions that are tension-leg type, piling, and floating support type subjected steady and sinusoidal oscillating flow. So they said that we must consider about the fluid force. In this paper, we proposed the air spouting type actuator to reduce fluid force of S.F.T's main body subjected to sinusoidal oscillating flow. We testified effects of the control system for reducing fluid force acting on S.F.T. to measure C_D, C_M, C_L., and phase angle between displacement and force experimentally. We found that this actuator reduce fluid force effectively at some parameters (Air Spouting Fraction, K. C., spouting pattern).

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This paper proposes the concept of sky-hook spring applying to an electromagnetic suspension with zero-power control. The authors combined the concept of zero-power control with sky-hook spring and damper to make the floated mass in the electromagnetic suspension system followed the rail with zero power in low frequency, with excellent performance of vibration isolation in high frequency. In experiments, an accelerometer and a high-pass-filter is used to realize the sky-hook spring and damper for isolating vibration in high frequency. The measured gap with a low-pass-filter is used to stabilize the electromagnetic suspension system under supporting the floated mass by a permanent magnet. Experimental results with current or voltage control of the electromagnet verified the capabilities of the control methods proposed in this paper.

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The design methodology of a vibration suppression system of the passive/active hybrid type by using piezo-elements as actuators is proposed. The vibration suppression system is optimally designed to minimize the objective function subject to several constraints. These are, side constraints of the design variables, behavioral constraints and the governing equations of the closed loop system. The objective function is defined as the maximum value of the transfer function of the closed loop system. The parameters of the shunting electrical circuit connected to the piezo-elements of the passive system and feedback gains for generating the control voltage applied to piezo-elements in the active component are taken as design variables. In the numerical example, the vibration suppression system for a cantilever beam is designed. Each piezo-element is separately bonded on the beam surface. The results obtained by optimization indicate that the hybrid vibration suppression system is quite effective under the trade-off conditions between vibration suppression performance and control energy consumption.

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In order to improve human comfort during winds and earthquakes excitations, two hybrid mass dampers with convertible active and passive modes using AC servomotors were implemented to a tall building in Yokohama, Japan in 1996. The objective building has a 133 m height and a 53000 t total weight. The each mass damper has a 50 t weight of moving mass supported by a XY motion mechanism vertically while coil springs and oil dampers horizontally. Control systems, for each 1 st mode of X and Y translations and a torsion of the building, are mainly designed by the LQ control strategy. Furthemore, gain-scheduled control is adopted. Active-passive mode switching rule is determined by overload conditions of the motors and the mass displacement. Conrtol performance test were carried out and large damping effects were obtained for the three objective modes of the building. The control performance against an actual disturbance was also confirmed through measured records under a strong wind condition and earthquake.

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In these days, there are many reports about marine development in several countries especially Japan and Norway. In this paper, we researched for the unsteady fluid lift force on S.F.T modeled by circular cylinder caused by vortex and examined air spouting type actuator for reduction of this unsteady fluid lift force. We can recognize that this actuator has ability to reduce (C_ln) at some parameters (void fraction, oscillation ratio, non-dimensioned velocity, oscillation frequency, spouting patterns) but made C_dn increased. So that, we propose the most appropriate parameters to reduce C_ln and increased C_dn at minimum experimentally.

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New mass measurement systems using a dynamic vibration absorber are proposed, in which a mass to be measured is attached to the absorber mass. Such mass measurement systems are named as vibration type, and their measurement principles and characteristics are studied with their basic models. It is also pointed out that mass measurement systems using a dynamic vibration absorber can be classified in several ways, for example, according to the motion of a mass to be measured, the type of the absorber, the method of exciting vibration, etc. An apparatus with an active dynamic absorber and an inertial-mass type vibrator was developed for experimental study on vibration type mass measurement. Experimental results demonstrate the effectiveness of the proposed mass measurement method.

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An identification method of vibrational damping parameters for laminated composite materials is presented by using the finite element eigenvalue analysis. A shell element for unsymmetrically laminated composite materials is formulated with the first-order shear deformation theory. The vibrational damping model of fiber reinforced plastic plates proposed by Adams et al. is used to calculate damping ratios for idenification problems. The identification problem of vibrational damping parameters can be converged as a nonlinear optimization problem. Vibrational damping parameters of unidirectional laminae are identified by using the quasi-Newton method, so that damping ratios of laminated composite materials calculated by the finite element eigenvalue analysis may be agree with those measured by the vibration test. An numerical examples, vibrational damping parameters of unidirectional laminae are identified and compared with the experimental results.

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CFRP is utilized as a material for the shank of boring bars, to achieve higher cutting performance than that of conventional steel shank bars or carbide shank bars. Natural frequencies of CFRP considered its anisotropy by the rule of mixture is calculated by FEM. The equivalent mass-spring method is proposed to estimate the loss factor of CFRP. Combination of ultra-high modulus carbon fiber and matrix resin formulated to have specific damping characteristics consistently gives both of high natural frequencies and high loss factors. The loss factors of CFRP boring bar are calculated based on the mode strain energy method. High damping CFRP boring bars can be stably used at higher surface speed with longer critical overhang without chatter vibration.

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A basic motorcycle dynamics model having four degrees of freedom was experimentally confirmed in this study. The frequency response functions, damping properties, and natural frequencies of weave and wobble modes which are vibrational modes of straight-running stability, were calculated using this model. Conclusions were drawn about effectiveness of the model from comparing of calculations and running experiments. (1) The four-degree-of-freedom model is effective for predicting steering response of the motorcycle during normal running conditions. (2) The weave mode calculations compare favorably with experiments in damped natural frequency, and agree approximately with experiments in damping ratio. (3) The calculated and experimental values of wobble mode are not necessarily the same with each test vehicle in damped natural frequency, and may differ in damping ratio.

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This paper describes a methodology to design layout and cross-sectional shape and size for beam-like reinforcement to improve eigenfrequency. In case of the optimization for a structure using beam model, the topology, the layout, the cross-sectional shape and the size must be decided as design variables. In addition, some variables must be determined simultaneously because they have effect each other. Previously, we presented the design method which a layout and a cross-sectional shape are designed considering each correlation with feedback loop. In this paper, we describe a new method which has been improved previous method. The improved point is to be able to consider to insert some reinforcements for base structure. The design method which refers to the deformation on main structure is applied to least weight structural design with eigenfrequency constraint. In order to confirm a validity of proposal method, it is applied to design the reinforcement for three-dimensional beam structure. We have obtained the layout and the size of reinforcement for vibration proof.

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A simultaneous optimum design problem of structural and control systems is discussed taking a 3-dimensional truss structure as an object. We use descriptor forms for a controlled object and a generalized plant because the structural parameters appear naturally in these forms. We consider minimum weight design problem for structural system and suppression problem of the effect of disturbances for control system as the purpose of the design. The structural objective function is the structural weight and the control objective function is H_∞ norm from the disturbance input to the controlled output in the closed-loop system. The design variables are cross sectional areas of the truss members. The conditions for the existence of controller are expressed in terms of linear matrix inequalities (LMI). By minimizing the linear sum of the normalized structural objective function and control objective function, it is possible to make optimum design by which the balance of structural weight and control performance is taken. We consider in this paper the validity of simultaneous optimum design of structural and control systems.

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The conventional method for modal test reference selection based on singular value decomposition of measured frequency response function matrices needs large numbers of selection processes, when many reference locations are initially proposed or many modes exist in the analysis frequency range. An alternative procedure to identify the least numbers and locations of references to be adequate in the overall determination of all the modes of the system is proposed in the paper. Firstly, a new method for selecting modal test references based on evaluation of effect of input force vectors to output responses is presented. Secondly, the advantages of the proposed method to the conventional one are shown by using numerical simulation concerning with two structural models.

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This paper describes a laboratory study of annoyance caused by road traffic noise. To measure the annoyance caused by road traffic noise, two kinds of subjective evaluation test were carried out; the one using 30 road traffic noise recorded on a road side with projection of video film of the scenery around the road side with and without the visual existence of traffic flow, the other using 48 road traffic noise recorded simultaneously at the location where direct sound propagation from the main traffic was confirmed and at the location behind the building without direct sound propagation. Among the frequency spectra of test noise in the second test, the differences on the SPL of high frequency component were significant. As a result, we found that: (1)from the first test the visible influence of the traffic flow to annoyance was not significant, and (2) from the second test, annoyance was different due to the differences on the high frequency noise while L_Aeq of road traffic noise were the same, (3)fluctuation strength had the highest correlation with annoyance, (4)besides L_Aeq, roughness and sharpness significantly contributed to annoyance simultaneously.

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A slit, which is a duct expansion with very short axial length, acts as a resonator muffler. Its resonant frequency almost depends on the slit depth, if the slit center coincides with the duct axis. Hence, it is expected that the resonance characteristic changes using a slit with non-uniform depth in the circumferential direction. In this study, transmission coefficient of the slit eccentric to the duct axis was measured with various slit-diameter, width and eccentricity, and with the plane wave or the (1, 1) mode wave incidence. As a result, it became obvious that the eccentric slit has two different resonant frequencies. Especially the lower one is peculiar to the eccentric slit and considerably lower than the resonant frequency of the concentric slit with same diameter. As the case may be, the eccentric slit seems to be useful as a sound attenuator.

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A new method to estimate the optimal parameters in Tchebychev iteration has been developed. In this paper, a self-tuning regulator was adopted and the optimum parameters in the Tchebychev iteration method were determined according to the results of identification. Moreover, we accelerated the convergence of the approximate solution to the exact solution by considering the reliability of identification results. The diffusion problem with the convection term was used as a test problem and the present method was compared with the CGS method. The memory capacity required for the present method was much smaller than that of the CGS method, but the present method exhibited an excellent performance to the problems which had the marked nonsymmetric coefficient matrices.

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In this paper, a measuring method of relative distance and orientation between vehicles by image processing and flexible target point following algorithm suitable for vehicle-following system are proposed. Generally, measurement precision depends on distance to target object, but we could measure independently of distance and in high precision by zoom control. As a steering algorithm, target point following algorithm suitable for vehicle-following was proposed in the past, but it was reported that the algorithm does not always decide every orientation on target point and sometimes there is an possibility to go a long way for the target point. So we improve this algorithm by putting a revised point between vehicle's now point and target point when the target orientation can't be decided. By this algorithm, range of orientation on target position that we can set becomes more and more wide than that was. We call this algorithm flexible target following algorithm. From vehicle- following experiment with these methods, it is confirmed that these methods are very effective to vehicle-following system.

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A New Automatic Coil Recognition System has been developed for the purpose of full automated crane operation in the steel coil transportation fields where great demand for automation can be expected. The sensed information including the coil position and the dimensions from the Automatic Coil Recognition System are sent to the crane operating controller and these information will enable the crane to operate with full automatic mode from the transportation work of the coils on the trailer truck which has been forced to work manually. This report describes the summary of the Automatic Coil Recognition System, its algorithm and the result of performance test.

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In the previous paper we discussed a method for measuring displacement on one circumference. Five sensors are attached to the measuring apparatus. One is rotated and the others detect the rotary errors. In order to measure more precisely, we discuss a method which is separated rotary errors from measured values by coordinated measuring machine on basement plate. This paper describes the method for measuring flatness without using transfer function. This paper shows the experimental results and computer simulation to investigate the theoretical results. In order to get large flatness, we show a method that flatness is calculated from the displacements on several circumferences by least squares.

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A new tactile sensor applying an optical waveguide plate was developed to detect not only three-axis force but also hardness and surface profile of an object. The sensor comprised a plane rubber sheet and an acrylic plate (optical waveguide plate) forming into an array of pyramidal projections. The reverse surface of the rubber sheet was checkered with square concave and convex portions; step height arising between them was about 0.3 min. Since the single concave or convex projection was arranged to press 2 times 2 array of pyramidal projections, three-dimensional force applied on reverse side of concave or convex surface was calculated from distribution of the four contact areas of the projections. The hardness of the object was measured from difference between contact areas of the concave and convex portions. A series of finite element contact analyses was performed to provide relationship between the step height and hardness. Experimental results showed that the present tactile sensor was capable of detecting three-axis force, and that the hardness and surface profile of the object were confirmed to be measured from the difference between contact areas of the concave and convex portions, and the distribution of indentation depth by the pyramidal projections, respectively.

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A learning control method, which generates feedforward inputs described by B -spline curves, is proposed. The algorithm is composed of two parts: Local Learning (LL) and Global Learning (GL). LL iteratively improves a feedforward input to approach the system output to a specified desired trajectory. GL identifies the controlled system dynamics by trial movements. The method has following features: (1) Describing inputs as B-spline curves has two merits: Input trajectories obtained by LL need relatively less meories to be stored and they are useful for the feedback control because of their differentiability. (2) LL is expressed by a simple iterative rule. (3) The gain matrix of the iterative rule is determined by GL. (4) GL is useful in the meaning that the identification process does not need any knowledge about the number of parameters and the order of dynamics. (5) The inverse dynamics obtained by GL generates the input trajectory which is a good initial trial for LL. The proposed method is effectively applied to the tracking control for a one-link flexible arm.

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Flexibility in joint drive systems causes robot arm vibration. The conventional semi closed-loop control cannot provide a high servo stiffness and large bandwidth for industrial robots. To achieve a high speed and high precision control, it is important to reduce vibration of robot arm and effect of disturbance. For this purpose, state feedback control becomes more and more important in practice. In this paper, we present an analysis and design of state feedback control for two-inertia system. From the viewpoints of non-negative positional stiffness and internal feedback construction, the domain of pole assignment is analyzed. The effect of disturbance is compared and evaluated for three optimum pole assignments, and the worst case of disturbance is also introduced. It is shown that choice and design of optimum pole assignment are very important when considering the effect of disturbance.

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In order to apply to the eyes of an autonomous running vehicle, a real time range finder has been developed that can measure the distance to every point on the plane without any pattern and its inclination. Though it seems contrary to the fact that the parallax is inversely proportional to the distance, this paper derives the mathematical grand that the plane in a real three dimensional space (X, Y, Z) is mapped also into the plane in a parallax space (x, y, Δx). On this grand, an electronic circuit has been manufactured which can compute in video rate the interpolation value between the parallaxes at two characteristic points by using several CPLDs. It is also shown that this device is applicable to the measurements of the slant angles of and the directions normal to the simple plane.

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In this paper, we propose "contact-state transition graph" for planning of graspless manipulation. Graspless manipulation is human-like dexterous manipulation method in which robot fingers do not grasp an object and manipulate it with support by environment. In graspless manipulation, the object contacts with environment several ways. Several patterns of contact state between an object and environment are described as nodes of graph and are connected by arcs which describe grapsless manipulation methods. From this graph, we can find the minimum cost path from start state to goal state. For correct a cost and state transition, we introduce parameterized node in the graph.

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The analysis of the head positioning error is one of the most important themes for increasing the areal storage density of magnetic disk drives. In this paper, the sensitivity of the position error signal (PES) is corrected for its nonlinearity with an adaptive gain estimator. PES is divided into the repeatable positioning error (RPE) and the non-repeatable positioning error (NRPE). RPE is transformed into the repeatable head displacement (RHD) which is evaluated in the track width variance and the write-to-read track misregistration (TMR). NRPE is decomposed into its contributing components which are the mechanical vibration, the flutter vibration, the position sensing noise and the force disturbance. Finally, NRPE is transformed into the real NRPE which doesn't include the position sensing noise.

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The precise positioning stage is ordinary mounted on the isolated table. For the positioning of its stage, PID compensator is widely used. There are many PID tuning methods, such as the ultimate sensitivity method. However, these methods are effectively applied to the plants described by "first-order lag+dead time". Then, it is difficult to realize the desirable positioning for the stage mounted on the isolated table by the simple applying of these method. Therefore, the knowledge based adhoc parameter tuning has been carried in the production field. However, this tuning easily introduces the tradeoff between the command and disturbance responses and then an adequate compromise is required. In this circumstances, we have doubts whether absolute positioning ability inherent in the stage itself is actively used. In this paper, in order to progress the positioning performance of the stage, we try to derive the tuning formulas based on Kitamori's method. The command and disturbance designated formulas are derived. Through the numerical simulation, it is clear that the practical formulation can be derived.

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Research on housework labor saving and automation for housework robots is growing as the population grays and improved electronics are becoming available to the home. Special problems for housework robots include the enormous reecognition complexity needed if such robots are to be highly independent of the work environment. Robot must deal, for example, with the variety of "nonsolid" household objects. We studied the technology by which a robot handles nonsolid objects, focusing on putting clothing to order at a specified site. Concrete subtasks this involves include removing one type of clothing from a wash and spreading out, classifying, folding, and putting it in a specified place. This paper propose a "unfolding" planning strategy.

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This paper describes the implementation of the singularity-consistent (SC) approach, proposed previously, for a space teleoperation system. The SC approach is suitable for Cartesian-space velocity control around and at kinematic singularities. Motions can be generated precisely and without producing any infeasible joint velocity. There are, however, some specific problems to be considered when implementing the method. First, the command direction must be precise, and second, the operator should be able to comprehend the state of the slave arm around the singularity. These two problems are not easy to solve for the operator. Therefore, we propose here a suitable supporting system based on virtual reality and shared control. Experimental results show that a real peg-in-hole task including through singularity motion, can be realized by means of a hand controller, even if there is time delay.

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Force control is one of the most important and fundamental tasks of robot manipulators. In order to realize precise contact tasks with an nuknown environment, robot controllers have to adapt themselves to the unknown environment. Recently, fuzzy reasoning and/or neural networks are expected to play an important role in force control of robot manipulator. Human knowledge can be reflected in control rules by using fuzzy control method, and learning/adaptation ability can be obtained by applying neural networks to robot controllers. In this paper, an effective control policy for robot contact tasks with an unknown environment is proposed using fuzzy-neuro techniques. In this control policy, a neural network is applied to classify the unknown environment based on its dynamic response of the environment and then select the suitable fuzzy neural force controller. The selected fuzzy neural force controller is able to realize the desired contact force precisely using its on-line adaptation ability. Furthermore, the fuzzy selection of the controller is introduced for force control with the environment whose suitable fuzzy neural force controller is not prepared. The effectiveness of the proposed method is evaluated by experiment with a 2DOF planar robot manipulator.

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This paper presents an Omni Directional Mobile Robot which can run on off road and run over an obstacle. The robot is constructed with four crawler-roller-motor-units and called "roller crawler-type of omni-directional mobile robot". Each crawler-reller-motor-unit can be driven independently and the motion of the robot can be controlled by the speed of motors. We also designed a position and velocity control system for the robot. The robot can be automatically controlled to run in optional direction and to track an orbit. The efficiency of the mechanism and the control method has been verified by many practical running tests and computer simulations.

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A cooperative control approach between human and robot is important for an assisting robot system which is requied a smooth and safe contact motion when a robot makes contact with a part of the human body. The contact motion is carried out safely to fuse the recognition ability of the human operator and the sensing functions of the robot. In order to inhibit the impact force, the approaching velocity of the robot to the exvironment is adjused through the master operation by the human operator and the direct human control system is designed based on an impedance control approach to achieve the flexible motion of the robot. It is difficult to cope with the change in conditions which occurs in a short time such as contact motions by the human operator. The degree of cooperation between human and robot is adequately adjusted by fuzzy reasoning during execution of the contact motion. In this paper, the contact stability is analyzed using a root locus method. The proposed cooperative control method is applied to a pneumatic robot with three degrees of freedom. The experimental results indicate that the cooperative control method is available for the contact motion to the environment.

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This paper is concerned with the development of a palpation sensor for possible detection of prostatic cancer and hypertrophy. The sensor is a layered medium with two polyvinylidene fluoride (PVDF) films embedded in the matrix sponge rubber. This sensor fixed with a finger is pressed against the prostates and the output voltage signals from the polymer films are measured. The temporal mean values, I₁ and I₂, on the absolute signals from polymer films are calculated and their ratio I₁/I₂ is used as the sensor output. First, the experimental method for the clinical test is proposed. The prostate glands diagnosed by a doctor's fore finger are classified into four groups according to their stiffness and the data processing for assorting the glands into the groupes are presented. The effect of the convexes placed on the surface of sensor is examined by conparing the clinical data with that of the sensor without the convexes.

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Lower limbs can be modeled by muscles, skeletons and joints with several kinematic redundancies. For restoration of locomotion in paraplegics by F.E.S., a number of muscles in the legs have to be chosen to generate the forces for realizing the gait. However, it has not been clarified how to select the muscles stimulated for the restoration. We have proposed Muscular Strength Stiffness Ellipsoid (M.S.S.E.) which describes mapping the muscle forces to the acting force on the center of gravity. Using the M.S.S.E., we analyzed the relations between the force of muscles and the acting force on the center of gravity.; moreover, the function of the redundant muscles is characterized using M.S.S.E.. This result is useful for the choice of the muscles in the restoration of the locomotion by F.E.S..

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It is said that characteristic frequency distribution of a cochlea is quite wide and a cochlear basilar membrane (BM) plays an important role in its frequency selectivity. It is also known that a traveling wave propagates along the BM from base to apex. Recently, it has been reported that outer hair cell motility amplifies the BM vibrations. However, the dynamic behavior of the traveling wave propagated from base to apex on the BM is obscure. Therefore, in this study, first, the glass microbeads are dispensed into the cochlea from a small hole which is opened at the scala tympani of the basal turn and fell onto the BM, and the BM vibrations in live and dead guinea pigs are measured directly using a laser Doppler velocimeter coupled to a compound microscope. Then, an attempt is made to clarify the dynamic behavior of the traveling wave. Results indicate that the traveling wave velocity depends on the BM vibrations amplitude and that the traveling wave velocity when the BM vibrations amplitude is large is smaller than that when its amplitude is small.

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The man-machine interface is an important factor in the computer system, and it is thought that line-of-sight (LOS) detection technology will allow significant advances in this field. Techniques for detecting LOS for use in human interfaces have been studied. In earlier studies, however, LOS was detected with a head piece, goggles, or through fixing the position of the head. The limitations imposed by these fixed conditions render them unsuitable for use in interfaces, as they have adverse mental or physical effects on humans. Therefore, they have not been sufficiently developed for practical application. Research on non-contact LOS detection is expected to result in a usable LOS-man machine interface, and the current study is intended to be a step in that direction. The authors used color contact lenses for LOS detection, and applied this new method to a computer interface. The use of color contact lenses simplifies image processing. The algorithm used in this study is sufficiently accurate for practical applications. This technique can be used in input devices, in virtual reality applications, and in human engineering research.

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Contact condition between a cross section of a finger and a plane plate was analyzed in our previous study. In this study, transient dynamic response of the human finger skin and strain energy distribution at the tactile receptors are calculated when the finger is in contact with sinusoidal wave representing the surface roughness of objects. Especially, the effect of epidermal ridges, velocity of the finger movement and wavelength of the sinusoidal wave on the tactile sensation are focused. FE (finite element) model using measured geometric and material properties of an actual index finger is used. The contact between the finger with/without the epidermal ridges and the sinusoidal wave moved in the tangential direction after indented in the normal direction is calculated. It is found that Meissner's corpuscles are largely in relation with the detection of surface roughness, Merkel's discs do not detect the surface roughness when the wavelength is small. It is also found that the epidermal ridges change the pattern of strain energy density near the Meissner's corpuscles.

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Earthworm move on the complex uneven around by its own peristalsis. Therefore, earthworm like structure can be applied to a mobile robot which moves autonomously in a narrow pipe or on an irregular around. In this study we propose a simple two-dimentional link model consists of flexible bar elementswe capable of calculating the locomotion pattern of the soft creatures including an earthworm. Calculated locomotion pattern of the earthworm like structure is similar to the measured ones. It is found that the earthworm-like structure can move at a constant speed on the plane around when fiction coefficient is large enough. It is also found that the earthworm can move even when there is a projection or several segments are broken down.

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Numerous attempts have been made to construct the controlled ecological life support systems (CELSS). The system will be a unique tool for researches such as test beds for the global change problem, the solutions for a zero-emission society and the large-scale life support system in outer space. The morphogenesis of plants in the system may be affected by the environmental change derived from the scale-down in ecological system. However, if the morphogenesis of plants is made clear, the high efficiency and intentional agriculture system will be put into practice. The purpose of this report is to elucidate the photomorphogenesis of plants under the variety of irradiation conditions. The experimental results showed that the changes in irradiation period had a dramatic effect on the germination, the differentiation and the growth of plants. In the 12-hours cycle irradiation which was composed of 6 hours-bright and 6-hours dark, the growth was promoted, although the germination of peas was restricted. Mechanisms based on phytochrome, photosynthesis, circadian rhythm and source-sink relation were proposed to explain these behaviour.

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High efficiency and intentional agriculture system such as a plant-factory should be introduced into the controlled ecological life support systems (CELSS) for food production. However, the morphogenesis of plants in the system may be affected by the environmental change derived from the scale-down or the difference in ecological system on earth. Therefore, germinational characteristic and seismorphogenesis of kidney bean were investigated by the culture system in which the germless soil was continuously reciprocated with a stroke of 60 mm. The growing rate was increased by the calmly stimulation where a frequency was 0.67 Hz. The wind generated by reciprocating motion might diffuse the atmosphere surrounding the plant, so that the photosynthesis was improved. The stalk of the plant was changed to a tall, narrow structure by the moderate stimulation where a frequency was 1.33 Hz. That structure seemed to ease the shock to the plant because of its flexibility. Ethylene production that was thought to be increased by mechanical stimulation may be one of the important factor for seismorphogenesis of plant. However, the mechanism based on participation of ethylene could not explain all aspects of the adaptive remodeling of plants.

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This paper proposes an approach to design an intelligent vehicle controller for partially supporting the driver's operation of a vehicle. Driving can be thought of as a system formed by the interaction between the driving environment, vehicle behavior and the driver's expectations for vehicle behavior. A visual information on the road environment is paid a lot of attention in our work. Driver's intention to accelerate or decelerate during driving operation comes mainly from visual information that the driver percepts. New power train control method that takes visual information into account is proposed. As a simple case study, narrow path between the parked vehicle and other vehicle is dealt with in this paper. Driver's mental model for passing narrow road is identified by a inductive analysis using experimental data. This mental model is installed to real experimental vehicle. As an example, a control procedure designed with the proposed model is applied to power train control. The experimental results show good performance in the vehicle control system.

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Tractor and semi-trailer combinations are usually coupled only by one position of the articulated point. Accordingly all the force acting on a tractor and a trailer relatively is to concentrate on this one point. This thing cannot be always considered as the best approach about stability and controllability of the articulated vehicle. So, we devised a new coupling mechanism to improve the stability and controllability of the tractor and semi-trailer combinations. In a word acting points of longitudinal and lateral force and of vertical force are divided with using the new coupling mechanism, and so, the stability and controllability of the articulated vehicle are improved. In this paper, we describe availability of the new coupling mechanism proved by experiments with a scale model and theoretical analysis with a mathematical model.

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This paper deals with a diagnosis of tooth surface failure by change in dynamic performance of a gear using the wavelet transform. The dynamic performances of the gear, which are tooth root strain and vibration acceleration of gear box, were mearsured during the fatigue process of the gear using a power circulating type gear testing machime. These dynamic performances were analyzed at a time-frequency domain using the wavelet transform. As the result of the time-frequency analysis of the vibration, it became clear that each failed tooth can be detected by this analysis when one tooth was failed. However, in the case of adjoining plural failed teeth, it was difficult to detect the all failed teeth. The result of the time- frequency analysis of the tooth root strain suggested that it is possible to detect the failed location on the tooth surface by this analysis.

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Reduction of bending stiffness in helical cords during bending fatigue was investigated carrying out some experiments, FEM analysis and mechanical analysis. The cords were constructed of stranded glass filaments and Resorcinol-Formalin Latex, and were used in synchronous belts. The stranded glass filaments were de-bonded and the bending stiffness decreased after the bending-fatigue. The FEM analysis showed that the reduction could be explained by the initiation and extension of the de-bonding in the cords. A simplified mechanical model was proposed to explain the reduction of bending stiffness of cords.

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Servo couplings are required both torsional rigidity and shearing or bending flexibility to maintain constant velocity between drive and driven shafts subject to one or more kinds of misalignment. Diaphragm couplings typically have the torsional stiffness several times larger than that of other types of flexible servo couplings. In the previous papers, the transmission errors and the lateral loads between the drive and driven shafts connected by a flexible coupling are measured. In this paper, the transmission errors and the lateral loads generated in several types of diaphragm couplings are measured, and the influences of the combination of parallel-offset and angular misalignments on them are clarified. The causes for the generation of transmission error in the diaphragm couplings are also investigated. The results may be summarized in the following. (1) Transmission error of single diaphragm coupling changes with a 2 cycle per 1 round and its amplitude increases as angular misalignment increases. (2) Double diaphragm couplings achieve excellent performance against parallel-offset misalignment, but the performance is lowered when the angular misalignment is added to the parallel-offset misalignment. (3) Transmission error of the diaphragm coupling can be estimated by the application of the equation to be used in the calculation for that of the double Hooke's joint (universal joint). (4) Lateral loads generated between the drive and driven shafts connected by the double diaphragm coupling are made up of the component proportional to the parallel-offset misalignment and the alternative component almost independent the misalignments.

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Generally it is well known that a coefficient of friction in abrasive wear can be expressed theoretically as a summation of the two terms related with a plowing and an adhesive component. It is, however, necessary to correct each term in order to adjust them to actual phenomena. In this work the correction factors to obtain a plowing component and an adhesive component occupied in abrasive wear were experimentally evaluated using a cone with various angles. The test materials investigated are carbon steel as cone specimen and tin and alminium as flat specimen. As results they were much deviated from the calculated values theoretically and the values of the correction factors varied with experimental conditions.

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Tribological properties of magnetic disk with diamond and Al₂O₃ TiC sliders were studied by disk contact sliding tester and reciprocating tribo tester, and then the contact principal and shearing stress were analyzed by the boundary element method. The following results were obtained. (1) Friction coefficient of magnetic disk with diamond tip lubricanted with PFPE is low asμ=0.1-0.8 evaluated with magnetic disk contact sliding tester. In contrast, the friction coefficient of magnetic disk slid with Al₂O₃ TiC slider is as high asμ=0.5-1.4. This result is mainly deduced to the low shear strength of PFPE lubricant between diamond slider and magnetic disk surfaces. (2) Wear rate of magnetic disk slid with Al₂O₃ TiC slider is larger than that with diamond slider. Plastic deformation damage were formed on the magnetic disk surface with PFPE boundary-lubrication. When a diamond is used as opposite sliders, wear on the magnetic disk surface can be reduced. (3) To clarify the reason why less wear of magnetic disk with diamond slider, stress analysis was carried out by the boundary element method about each sliding combination. The maximum shear stress of magnetic disk surface slid with diamond slider is less than that of the magnetic disk Al₂O₃ TiC combination. The wear rate of the magnetic disk slid with diamond tip is very little due to the low shearing stress of surface because of the damage seems to be originated from sliding surface. (4) Wear rate of magnetic disk corresponds to the maximum shearing stress on surface. To realize accerarated wear test of magnetic disk contact sliding test with the analysis of maximum shearing stress of surface, the running in effect must be evaluated.

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A modified Reynolds equation and oil film velocity expressions are derived with centrifugal force acting on the oil film being considered. The equation is applied to the lubricating oil film assumed to be concentric in very high speed journal bearings, and solved for the pressure variation in the axial direction and also across the film thickness. Linked with the cavitation model proposed by Koeneke et al., the lubricating film is theoretically found to rupture near the journal surface toward the bearing end. This axial oil film rupture is shown to reduce the driving torque of the inner film of floating bush bearings at very high shaft speeds, and this analysis can give a reasonable explanation to the phenomenon that the bush-to-journal speed ratio is observed to decrease with shaft speed in actual high speed machinery, though conventional theoretical models could not.

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