This paper describes natural frequencies and damping ratios in a high-rise steel building. The object building which was completed in October 1998 is 120m height and rectangular plan. The microtremor has been measured periodically for more than 100 months since completion. The acceleration data and the velocity data in two horizontal directions and torsional direction are analyzed on 1st mode to 4th mode. It is studied the changes along passages of natural frequencies and damping ratios in microtremor and relation between amplitude and damping ratios in free vibration waves by manpower excitation.

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This paper describes the vibration characteristics based on measurement data concerning a middle rise building framed by steel. This building is rectangular plan and 43.5 meters height. After completion in March 2004, microtremor measurement is continued periodically in the building. Many data are recorded in two horizontal directions and torsional direction. The content of this study is examination of natural frequency and damping ratio changes along passages with dispersion. And it is studied vibration characteristics of the building in consideration of the underground on earthquake observation data.

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Structural damping can be improved by installing high damping alloy in steel structures. This paper presents the results of fundamental study to increase structural damping by adding high damping alloy in the steel structure. Vibration tests using models composed of stainless steel plate and small Mn-Cu alloy plates, and vibration analyses of the models were carried out to investigate damping ratios and natural frequencies of these complex plate structures. From the experimental and analytical results, the effects of installation positions and installation sizes of the Mn-Cu alloy plate on the damping ratios and frequencies of the stainless steel plate were clarified.

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This paper deal with the modeling of the magnetic damper based on Lorents force. We have built the experimental setup composed of a ring shaped magnet and a hollow-cylindrical conductor. In the modeling, we can use an infinitesimal rectangular loop coil whose face is perpendicular to magnetic in the radial direction. In the previous paper, we made the same model using the loop coil whose face is perpendicular to the relative velocity of the conductor. Consequently, we have found both results agree. Experiments were performed, and compared to analytical results. As a result, the analytical results agree well with the experimental results.

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Colloidal damper is composed of cylinder-piston mechanism contained colloidal liquid which is composed of hydrophobic silica gel and water. The silica gel has many small pores in it and the water comes in and out the pore by the variation of pressure. The surface extension forces of the water in the pore are different at the process of coming in and out. This difference makes dissipative energy as the damper. In this paper behavior of water which is coming in and out the pore is stimulated by using the molecular dynamics and the evaluated energy by the molecular dynamics is quantitatively compared with the energy experimentally obtained by colloidal damper and the both results are good agreement. That is, clastered water used by molecular dynamics is entered into and come out 7-10 nm dia. pore coated by hydrophobic molecular and both contact angle are measured and the dissipated energy is evaluated. Then this energy is compared with the experimental result which is obtained by colloidal damper. Then these results have good agreement.

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Conventional linear viscous damper has the trade-off characteristics between the vibration suppression effect of peak resonances and the increase of vibration between the resonance points. This paper investigates the nonlinear property of the step function type damper which can solve such problems. The two-degrees-of-freedom system is considered and the proposed nonlinear damper is installed between the mass points. The optimization method of the damper is discussed in order to design the performance of the nonlinear damper. The effectiveness of the proposed nonlinear damper is demonstrated experimentally using a magnetic damper.

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Experimental investigation into the dynamic behavior of vibration system with granular materials has been carried out using forced vibration system with single degree of freedom. The vibration system was excited in forced vibration by foundation motion at the natural frequency of the system, and two accelerometers were used to simultaneously measure their respective accelerations. We took a motion of the granular materials with a high speed videocam and analyzed their motions. We then discuss the relationship between the damping characteristics and the behavior of granular materials. Furthermore, we evaluated vibration characteristics of the damper when diameter of granular materials and depth of the granular-container were changed.

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In the previous paper the authors proposed a new vibration control device (V.C.D.) using power generator. The device has an inertial force created inertia disk, and damping force derived an energy dissipation of the power generator. The trial experimental model was made, and the vibration tests were carried out in our laboratory. In this paper, for the purpose of applying the device to a real large structure, new two V.C.D.s for 15 kN range are manufactured, and shipped to NCREE, Taiwan. In order to investigate about dynamic properties of the V.C.D., performance tests are carried out, and the resisting force characteristics are measured. Next, vibration tests of 3-story structure when the V.C.D.s are attached are carried out using by shaking table. Seismic responses at each story are measured when the earthquake wave of Imperial Valley El Centro NS component is inputted. The control law based on minimizing the Lyapunov function is used, and it is controlled by Bang-Bang type. The effects of vibration suppression using the V.C.D. are confirmed.

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Damping characteristics and amplitude dependency of natural frequency of rocking of rigid body is discussed. Equation of damping ratio of rigid body is derived by integrating planer equations of motion of the rigid body during the collision period assuming plastic collision. In order to design damning ratio and natural frequency of rocking of rigid body as dynamic vibration absorber, we examine damping characteristics and natural frequency of rigid body with polygon base. It can be seen that damping ration and natural frequency of the rigid body can be controlled easier by using polygon base.

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In this study we make clear the dynamic characteristics of multi degree of freedom system supported by air suspensions with viscous restrictions and a reservoir tanks. In order to minimize resonance amplitude T, the equivalent damping ratio ζ which corresponds to the restriction coefficient of viscous restriction has to be chosen in order to equalize T in case of β → 0 and T in case of β →∞. In order to minimize variance of amplitude V, ζ = α/2η when α < 1 and ζ = 1/2η when α &ge; 1, where α is the shape factor of the supported body and η is the ratio between the volume of the reservoir tank and the hole volume of air suspension.

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This paper describes an active control method using Coriolis force for reduction of a crane load swing. Coriolis force is generated when a mass on a wire of a crane moves up and down in the radial direction. In this research, crane load and Coriolis swing absorber are regarded as double pendulum connected by a light wire. Active control is used for moving Coriolis swing absorber in an attempt to meet changing natural frequency. The relation between the performance and the parameters is investigated by theoretical analysis. The effectiveness of the proposed method is verified by numerical analysis and experiments.

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The construction methods of acceleration input pattern which suppress the residual vibration of overhead traveling crane in positioning are proposed. The crane system is considered to be 2-DOF system, for inertia of moment of a load. The equation of motion for the inclinations of the wire and the load are formulated. By numerical simulation and experimental results, it is clarified that the combination of proposed methods can make the residual vibration small for two natural frequency conditions are satisfied. By window function method, the robustness is also achieved.

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A purpose of this study is to develop a passive absorber which makes it possible to suppress vibration of multi-degree-of-freedom systems using pendulum type dynamic absorbers which is called a parametric excitation dynamic absorber. Such a dynamic absorber generates vibration suppression near resonance frequency of the main system when a natural frequency of the dynamic absorber is adjusted to half of natural frequency of the main system. A pendulum of the dynamic absorber vibrates only around resonance frequency of the main system and does not vibrate except the resonance frequency. The adjusted dynamic absorber to 1st resonance, 2nd resonance, etc can suppress amplitude of the corresponding resonance and does not disturb the dynamic absorbers for other resonances because it vibrates around only resonance. A pendulum type dynamic absorber which includes a rotational spring and damper has been developed in order to expand a sphere of the application. Then 1st and 2nd resonances of three-degree-of -freedom main system have been experimentally controlled by the dynamic absorber. The dynamic absorber for 1st natural frequency of the main system reduces a peak of the 1st resonance and the dynamic absorber for the 2nd natural frequency also reduces a peak of the 2nd resonance in the experiment and the simulation. It is concluded that each dynamic damper becomes active only near the corresponding resonance and the main system vibration becomes small.

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Nonlinear vibrations in a two-story elastic structure carrying two rectangular liquid-filled tanks under horizontal harmonic excitation are investigated. Two cases are treated, (1) where the natural frequencies of sloshing in the tanks are respectively equal to the first and second natural frequencies of the structure, and (2) where they are equal to the first natural frequency of the structure. Modal equations are derived considering the nonlinearity of the hydrodynamic force. Then, frequency response curves are theoretically calculated by using van der Pol's method. It is found that amplitude modulated motion occurs when the liquid levels are high or when the excitation amplitude is comparatively large.

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Impacts of spheres are one of the basic and important problems in engineering. However, impacts often occur repeatedly in practical cases and repeated impacts haven't investigated so much yet. Consequently, this paper deals with the repeated impacts between two identical spheres. Numerical simulations were carried out by Finite Element Analysis. As a result, the coefficient of restitution rapidly increases with the number of impacts during the initial several impacts, and then approached to unity, and the contact time decreases with the number of impacts during the initial several impacts, and then towards a constant value.

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This sheet deals with characteristics of the oblique impact system, which is composed of the ball and elastic supported flat surface . The impact system is modeled by both a nonlinear spring and a nonlinear dashpot using Hertz's contact theory. This model is applied to the oblique impact system of ball. The characteristics of the oblique impact were obtained by using this model. The results show that the spin rate increased in proportion to the angle of incidence and impact velocity. Also, in the case of increase the tangential stiffness, the spin rate was decreased and the angel of reflection was increased.

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The collision vibration is widely applied to the impact machining device since accurately large energy is comparatively obtained. It is necessary to quantitatively analyze response vibration and restitution force by collision for design of the impact machining device. As an example of basic investigation, this paper deals with impact vibration in a spring-mass system for two-degree-of-freedom excited by periodic force with arbitrary functions. The analytical model is steady impact vibration for two-degree-of-freedom having two masses in which subjected to an exciting vibration. Then the restitution force, which has characteristics of an unsymmetric piecewise-linear system with hysteresis loop, collides elastically to anather mass when amptitude of the mass increases farther than clearance. In order to analyze the resulting vibration for the main resonance, the Fourier series method is applied to obtain an exact solution for response vibration. The numerical calculation is performed to obtain the resonance curves. The numerical results show effects of the stiffness of the clampted spring and the amplitude of excitation on the resonance curves.

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This paper deals with the response analysis of nonlinear vibration in continuous system excited by periodic displacement with arbitrary functions. A system of steady vibration in a simply-supported beam held by a nonlinear spring at midpoint of span is considered. The restoring force is assumed to be a piecewise-linear system. For such a system, the beam undergoes a nonlinear vibration when the amplitude is large. In order to analyze the main resonance for the system, the Fourier series method is applied to obtain an exact solution for response vibration. The numerical calculation is performed to obtain the resonance curves. The numerical results show effects of the stiffness of attached spring and the amplitude of excitation on the resonance curves. The experiments are also performed to verify the numerical results.

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This paper examines the validity of non-linear vibration analyses of continuous systems with an internal resonance. As an example, we treat a suspended cable with a one-to-one internal resonance ω_3 &ap; λ_3, where ω_3 and 3λ_ are linear natural frequencies of the third (second symmetric) in-plane and out-plane modes, respectively, and investigate the steady-state responses when a driving frequency Ωis near ω_3 . The steady-state responses are found by using two different approaches. In the first approach, the method of multiple scales is applied directly to the governing equation that is a nonlinear partial differential equation. In the second approach, we discretize the governing equation by using Galerkin's procedure, and then apply the shooting method to the obtained ordinary differential equations. In order to check the validity of the solutions obtained by the two approaches, they are compared with the solutions obtained by the finite difference method.

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Experimental and analytical results are presented on effects of axial elastic constraint on chaotic vibrations of a clamped-supported beam subjected to periodic lateral acceleration. The simply supported end of the beam is elastically constrained by an axial spring. Periodic resonance responses are investigated under various compressions. The chaotic responses of the beam under axial compression are examined with the Poincare projection, the Fourier spectrum and the maximum Lyapunov exponent. The frequency region of the chaos spread with the increment of the axial compression. Experimental and analytical results of the chaotic responses agreed fairly well with each other.

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This paper presents a procedure to derive reduced-order nonlinear equations using a projection onto a sub-space which includes solutions of whole-space equations in approximation. The sub-space is defined by vectors that are obtained by decomposing solution vectors of static nonlinear finite element (FE) equations on which equivalent inertia force is acting. Even though we consider a nonlinear vibration, it has verified that there are moments that assuming accelerations are almost proportional to displacements is not so reckless. Thus, solution vectors of static FE equations are able to regard as approximate solutions of dynamic FE equations at that particular moments.

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This study deals with nonlinear dynamics of a horizontally supported Jeffcott rotor. The equation of motion is derived by considering the gravity effect and the cubic nonlinearity of restoring forces. The linear natural frequencies in the vertical and horizontal directions are different due to the gravity effect and they are independently changed depending on the mass of the rigid disk. Also, the equivalent cubic nonlinearity, which depends on the mass of the rigid disk, determines the nonlinear spring characteristics of backbone curves. It is theoretically predicted that the decrease of the mass makes the nonlinear characteristics hardening and the critical magnitudes of the mass, at which the nonlinear spring characteristic is transformed from soft to hard, are different for lateral and vertical directions. The experimental results by a simple apparatus qualitatively confirm the theoretically predicted nonlinear characteristics of the horizontally supported Jeffcott rotor.

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Recently, the use of the wind turbine generator has rapidly spread as the one of the clean energy sources. Its size is becoming larger, and simultaneously, the maintenance of the turbine generator becomes more difficult. However, the conventional reserches aimed at the fluid engineering in order to gain higher efficiency, and only few investigation have been reported in the area of the vibration analysis and its suppression. The wind turbine is a special type of rotating machinery, and it requires the original point of view in the dynamical analysis. It has a long heavy blade which rotates in the vertical plane under the action of the gravitational force. The wind power acting on the turbine blade changes periodically because, for example, the wind power increase as the function of the height. This paper investigates the fundamental vibration characteristic of the wind turbine blade by using rigid blade model. The interaction effect of gravitational force and wind force on the vibration of the turbine blade is clarified. The super-harmonic resonances occur due to the effect of parametric excitation effect which is caused by gravitational force. Also, the occurrences of the unstable vibration ranges are indicated.

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Statistics of stochastic jump phenomena in the random responses of a Duffing oscillator subjected to narrow band excitation are investigated. The stochastic jump phenomena are characterized by existence of two states in the random responses and sudden jump between two states. To distinguish two states, we proposed the product of wavelet transforms of the excitation and the response, and showed that the product corresponded to the frequency decomposed phase angle between them. In this study, we calculate the rate of stochastic jump, the ratio and the mean duration of each state using this criterion.

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Estimation of instantaneous damping and frequencies by the wavelet transform is based on the ridge identification and the phase extraction in the time-frequency map. Time-varying parameters due to nonlinearities are also estimated by this technique. However, the process of the ridge identification is complicated, and the most suitable mother wavelet to yield a time-frequency map for an efficient identification can not be determinately chosen. There are some problems in easiness to operate the technique. In this paper, we propose the segmental use of the harmonic wavelet. The segmental harmonic wavelet is implemented in combination with the Fourier transfer, which is utilized to set bounds to frequency range. It shows significantly good results compared with the simple application of the Hilbert transform. The time-varying parameters pertaining to nonlinearities are successfully estimated by the proposed method.

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We propose a new collaborative control strategy between the time varying design parameter of the plant and the feedback controller. As the feedback control law we adopt LMI based gain scheduling control scheme to guarantee the closed-loop L_2 gain against the variation of the time varying parameter of the control object. Under the gain scheduling control we propose a method for the adjustment of the time varying parameter using the theory of dissipative systems. The objective of the time varying parameter tuning is to obtain smaller L_2 norm of the controlled output. We show that the tuning rule of the time varying design parameter becomes bang-bang type in some cases. We refer to this control strategy as Active Gain Scheduling Control (AGSC) because the scheduling parameter is actively changed by control designers.

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IPMC(ionic polymer-metal composite) actuator is one of the soft actuators to be expected as artificial muscles for small robots. The IPMC gel first bends quickly and then bends back slowly when a constant potential is applied to the sample. The latter phenomenon, reffered to as stress relaxation, is modeled by Electrostress Diffusion Coupling Model. We propose a dynamic state space model including stress relaxation. The result of the experiment demonstrates the validity of the model.

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Strain rate effects on the tensile response of pseudoelastic shape memory alloy wire are studied in this paper. Quasi-static tensile tests and high-speed tensile tests have revealed that both transformation stress and reverse transformation stress at a higher strain rate become larger than those of at a lower strain rate. A linear regression equation of the transformation stress in function of the logarithm of the strain rate has been found. By implementing this expression, a quasi-static single crystalline model by Brinson and a quasi-static polycrystalline model by Ikeda et al. have been successfully extended to derive constitutive models that are effective in a broad range of strain rates.

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This paper proposes a multidisciplinary optimization approach of smart structures with disturbance characteristic variation. The control system and actuator locations are optimized by genetic algorithm according to H_2 specification with a reduced-order modal model derived from FEM and modal analysis. A gain-scheduled control system is applied to cope with the disturbance characteristic variation. This system estimates the disturbance characteristics continuously and then uses the appropriate scheduling gains against the estimated disturbance characteristics. The scheduling gains are optimized by genetic algorithm to enhance the vibration control performance under a constraint on the control cost, beforehand. A time-domain simulation and experiment have been carried out to verify the performance of the presented control system.

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This paper proposes a controller design of smart structures by arranging low-order mode controllers in parallel for vibration suppression. The smart structure consists of a panel with one fixed end, one inertia mass supported by a piezoelectric actuator and control system, and the controlled object is modeled as a reduced-order modal model derived from FEM and modal analysis. By optimizing the parallel mode controllers, the order of whole control system is reduced. And the stability of the system is guaranteed by using positive real of loop transfer function. The control simulation is carried out using the designed controller, resulting in better closed loop performance for vibration suppression.

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Piezoelectric film has two effects of direct piezoelectric effect and inverse piezoelectric effect. These effects can be used for the vibration control of flexible structures. In the authors' previous reports, a self-sensing actuator with laminated piezoelectric films was proposed and the vibration control effects against first and second mode of a beam and first mode of a rectangular plate were shown. However, vibration control effect against multimode of two-dimensional structure was not shown yet. Therefore, in this paper, a self-sensing actuator using laminated triangular piezoelectric films was proposed and its analytical model was derived. Then the validity of the proposed method was shown by comparing the results of an experiment of applying voltage to a triangular piezoelectric film actuator bonded on the plate, with that of theoretical analysis. Finally, multimodal vibration control of simply-supported plate was studied by numerical analysis.

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This paper investigates a method of active acoustic vibration control and noise isolation by using a smart board equipped with the piezoelectric actuator. The smart board is designed as a separation wall for preventing the sound propagation through the wall and suppressing the sound-induced vibration. In this research, a hardware experiment has been made for evaluating the effectiveness of the smart board and the proposed controller. The control system is designed by using a mixed H2/H ∞ control, where the weighting functions in frequency domain are designed considering the dynamic characteristics of the smart board.

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The objective of this study is the loosening detection of bolted joints without human involvement by applying the concept of structural health monitoring. The smart washer consists of the cantilever available to detect bolt loosening by using flexibility of cantilever and self-sensing/actuation function. The principle of how to detect the loosening of a bolt is the basis that the natural frequency of a smart washer system vary depending on a bolt tightening axial tension. The natural frequency of the smart washer was identified by using the sub-space state space identification method in previous papers. However, 4SID was confirmed unsuitable for the periodic maintenance. This paper is proposed that the smart washer is detected bolt loosening by the supervisory method by using multiple observer. Numerical simulation results for several bolt loosening state for the bolted joint indicate the effectiveness of the proposed loosening detection method.

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Recently, an FBG sensor, one of the optical fiber sensors, has benn studied and developed for structural monitoring because of their higher performances. But in FBG sensing temperature variation is detected simultaneously with strain variation as wavelength shift, so it has been required to eliminate the temperature effect. The authors are developed new strain and temperature sensors by which we can obtain both strain and temperature independently with simple procedure. In addition, effect of thermal elongation of a structure is eliminated using these sensors. In this report, strain and temperature characteristics of the sensors are described and their validity is confirmed.

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The developments of practical application using the smart structure system are desired since recent years in Japan. The improvement of the social recognition for smart structure systems is an important subject, due to the concept of smart structure is not familiar in Japan. This paper addresses the example of the one-link robot arm as a home robot use by adopting the concept of smart structure. The supervisory fault diagnosis method with multiple observers is proposed for the purpose of the loosening detection to the fastened screw for the driving joint and arm structure. Numerical simulation results indicate to verify the effectiveness of the proposed method.

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The shape memory alloy (SMA) has hysteretic characteristics and temperature dependent properties of stiffness and damping. The vibration absorption property was investigated for vibration damping equipments and vibration isolation devices. Few works for dynamic mass dampers with SMA have been studied. The semi-active SMA mass damper by the temperature dependent property is considered to suppress vibrations. It is difficult to describe the temperature dependent property of SMA exactly. The fuzzy reasoning is used to control temperature of the SMA mass damper. The effectiveness of vibration suppression by temperature control of the semi-active SMA mass damper is verified.

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This paper proposes a new method of the hybrid vibration suppression using piezoelectric elements and the displacement signal of the object. A lot of hybrid methods have been proposed; however, most of them merely use both the active method and the passive one together. In contrast, the controlling force of the proposed method is based on that of the passive method. Because the governing equations of the proposed method are also similar to those of the passive method, the optimum values of the circuit can be determined by simple formulations derived by the two fixed points method. The performance and the stability of the proposed method were verified by theoretical analysis and the experiment.

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Piezoelectric transducer, which is a typical transducer utilized for smart structures, has many functions. It operates as an actuator producing control force, a sensor measuring deflection of a structure, and a generator producing electric power from vibration. By combining these functions, the piezoelectric transducer can realize active vibration control without a sensor and a power source. Through theoretical analysis and numerical method, feasibility of the proposed system is shown.

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Energy consumption to drive actuator is thought as a disadvantage of active vibration control. However, the actuator of active vibration control system absorbs energy from vibrating structure to suppress the vibration. In other words, the actuator regenerates energy from the vibrating structure. Especially, piezoelectric actuator can regenerate energy effectively, because it has few internal energy loss. In this paper, energy consumption of SDOF model with piezoelectiric actuator and feedback control is investigated as an example and it is shown that energy consumption is not caused by the actuator but caused by energy loss of conventional linear amplifier to drive the actuator. Recently, class D amplifier based on switching circuit has been utilized due to its high-efficiency. It can drive the actuator with few energy loss. Therefore, the energy regenerative active vibration control system can be realized by using the class D amplifier to drive the actuator. The validity of the system is shown by numerical simulation.

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This study investigated the evaluation of easiness to grasp the cylindrical pipe under the several diameter in the condition of static and dynamic movement at wrist joint. The optimum diameter of cylindrical pipe was 35mm condition of static movement. In the wrist joint movement, that are palmar-flexion, dorsi-flexion, ulnar-flexion and radial-flexion, the optimum diameter was a thin cylindrical pipe, and the values of mIMG of the forarm was constant value during wrist joint movement for two minutes. The optimum diameter differed with the intention of movement.

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This study investigated the evaluation of easiness to grasp grips of hand-made and of ready-made badminton rackets by means of the measurement of movable angle at wrist joint and EMG activity during racket swing motion for two minutes. The wrist joint movement were palmar-flexion, dorsi- flexion,ulnar- flexion, and radial- flexion, and the swing motion were forehand and backhand swing. Grip strength afrter continuous swinging hand-made racket was lager than that after swinging ready-made racket. EMG activity in grasping hand-made racket did not increase, but that in grasping ready-made racket increased. In grasping the hand-made racket, the movable angle of wrist joint was expanded in radial-flexion, compared with grasping the ready-made racket.

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For the design and development of vehicles, it becomes more important than ever to offer the comfortable drive environment. This study focused on the air-conditioning system of a car, and the comfortableness for a driver was evaluated using the bioengineering technology. The experiment was carried out by electroencephalogram measurement and electrocardiograph measurement for a driver near the air conditioning outlet inside the passenger car. As a result, the correlation between the comfortableness and the thermal environment was gained: 1. It became clear to be able to evaluate the amenity using electroencephalogram measurement ( content rate of α wave ) and electrocardiograph measurement (LF/HF value ). Though it is said that it is more comfortable when the LF/HF value is lower, and when the content rate of α wave is higher, both measuring results were well correspondent. 2. It was proven that the peak of the amenity for drivers appeared at some temperature (temperature of car's interior or near the air-condition outlet ) as experimental results. 3. It was also proven that not only the temperature but also the humidity influence the amenity.

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Sound quality of hitting sound becomes important in design of golf club. First we suggest sound quality evaluation parameters for sound quality improvement of the hitting sound. Then we examine correlation with the sensory evaluation. We show that parameter which has a problem in correlation is improved by examining subjects characteristic for sound quality evaluation. As a result, we show that there were three characteristic groups for pitch evaluation of the hitting sound, which are affected by frequency, loudness and reverberation of sounds respectively.

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This paper presents the fundamental study on the perception of tactile sensations by pushing. First, various tactile feelings of cushions are collected through questionnaires based on the paired comparison semantic differential method. Furthermore, the factor analysis is introduced to evaluate and classify the feelings. It is found that softness and elasticity are dominant factors. Next, questionnaires under various conditions are carried out on softness and elasticity. The relation of cutaneous sensation and deep sensation to tactile perception is discussed.

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The feeling of a wood-screw tightening using a screw driver has been examined. As a result, The screw driver cam be rotated when the screw driver bit size is smaller than the cross-grove size of screw head. However, the operation time of screw closing become long as those incompatibility degree increases. It has been understood that thess cause are the stability during screw driver operation at the early stage of screw tighening. Moreover, increasing the wood hardness tends to in crease the operation time, fatigue, the feeling of a wood screw tightning and the feeling of grasping.

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Relationship between operatability of excretion support equipment for wheelchair users and grip diameter of controller had been investigated. Length from the controller to the actuator had an optimum value related the length of user's hand. The optimum length in this study was 350mm. Moreover, the diameter of grip had an optimum range from 20mm to 35mm. This diameter range was smaller than that of power grip. It is understood that the operations in this study were precision grip concerned with the fingertrip.

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Flexible wheels have been developed to improve the ride comfort. This wheel is equipped with unique fiber reinforced rubber rings between the disc and the rim, in order to reduce noise and vibration without any compromises with handling and stability. This paper discusses effectiveness of the flexible wheel when weight unbalance added through the uniformity tests, and proposes a new uniformity test method which can simulate more realistic conditions of driving than the conventional method. Simulation analysis was carried out for the new test method, showing that flexible wheels could reduce more radial force variation compared with the conventional wheels.

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System control and identification often require accurate estimations of velocity and acceleration from measured displacement. This paper proposes a novel FIR filter for velocity and acceleration estimation, where the filter coefficients are derived by piecewise Radial Basis Function Network (RBFN). The proposed FIR filter achieves the prescribed lowpass property, and the specified group delay in passband. The estimation method is implemented on a system identification in which the time-varying physical parameters are directly identified from the measured displacement that is contaminated by Gaussian noise.

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In this paper, we propose the touch panel's operation by using human fingernail and finger. And we developed the control circuit that measured coordinates and the electrostatic capacity in the resistive type of touch panel for this realization. In this device, the measurement of coordinates and the electrostatic capacity was possible. In the operation test, the input of fingernail was a tendency to distribute downward from the input of finger, and 90% success area was about 12mm. This operation suits the Fitts' law because the contribution rate is above 0.8 in the operation time and the index of difficulty.

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In this research, it proposes the Hi-Tc superconducting levitation synchronous motor by using an outer field reversal about the levitation body. This levitation body is a permanent magnet magnetized in the thickness direction The multipole field is given to outer by making this permanent magnet adsorb larger than the external radius of the magnet more sectorial magnetic material plate. In addition, an easy structural magnetic damper system was constructed for the sympathetic vibration control. As a result of the experiment, this motor was confirmed that it was possible to rotate at high speed without the control.

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