This paper describes an application of hierarchical neural networks to structural identification. The present procedure consists of three phases : ( a ) preparation of learning data, in which the learning data are produced through a number of FEM calculations with various identification parameters, ( b ) training of the neural network and ( c ) utilization of the neural network, i. e., structural identification. As the first step of the present research, this procedure is applied to the identification of material properties of an one-dimensional beam from its vibration characteristics such as eugenmode, and displacement, and acceleration distributions. In addition, the analog, digital and hybrid output methods are compared with one another from the viewpoints of efficiency and accuracy.

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The fuzzy expert system for abnormality diagnosis is developed for all component equipmet in the refuse incineration plant. As the fuzzy logic is applied to the reasoning engine practically, diagnosis can be made even in case of abnormality in unstable condition of the plant and of transitional condition of trouble and this system has more flexibility than that in the past. At the same time, the merits are brought to human interface such as the knowledge acquisition and modification work become easy or the process of diagnosis becomes understandable resulting from patterning the diagnosis knowledge by membership function. The process data are taken into the system at online and real time through LAN from DCS. The reasoning engine and knowledge are in the minicomputer and the diagnosis is performed by the program aimed at data base. The results of diagnosis are output by acoustic announcement and CRT display indication, and guide the support for extracting and remedy of the cause of abnormality. This system is entered into actual operation in several plants already.

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Sensing the density of the exhaust gas elements influenced by faults for ten minutes of engine start-up, the abnormalities of a diesel engine are predicted by a feature-sampling and discriminating processors, which are described by the neural network models. Three pieces of time response density data are transformed into feature data by the feature-sampling processor, which has learned the normal response data of the three gas sensors. At a result, we obtain a pattern which is composed of ten sampling data values at intervals of one minute. Using the pattern, the discriminating processors, which have learned the respective normal or abnormal patterns, calculate certain factors and discriminate and predict the abnormality of the engine combustion by consensus based on certain factors. We expect that this discrimination method will have robustness against the change of gas sensors as days go by, as well as against the start-up conditions of the engine.

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In conventional optimization methods, designers have to set mathematical modeling, such as objective function, constraints and design parameters, strictly and quantitatively. But in actual design process, they do not treat all of these values strictly and some of them are somehow "fuzziness". Recently, many studies have been done on fuzzy mathematical programming. In fuzzy non-linear programming. α-level cut method is considered as the one of the most popular and useful method. But in this method, we cannot see the relationships between fuzziness in constraints and design variables. In this study, we assign fuzzy numbers as design variables, and propose the optimization method using fuzzy number as design variables. We applied the proposed method to a simple truss optimization problem and examined the effectiveness of the method through comparison with the conventional α-level cut method.

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In the first report, we proposed a method of optimum design using fuzzy numbers as design variables. But in that report, all the calculations had been performed by a basic fuzzy number operator, so the problems to be solved are restricted only those whose equations are expressed explicitly. As most of the optimum design problems are not so simple, especially in structural design problems, it will be rather difficult and sometimes almost impossible to express the equations such as objective function and constraints explicitly. For this reason, we developed a simple fuzzy number operation and examined its adequacy through comparison with the basic fuzzy operation. In this report, we solve the same optimum design problem which was solved in the first report, and examined the efficiency of the method. We then apply it to the optimum design problem on the lib structure of a parabolic antenna, and we examine and show the effectiveness of the method.

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The optical filter is composed of transparent plastics and plural chemicals which have various transmittances. The determination of the amount of each chemical to be used is important in obtaining the desired transmittance. Previously, an expert drew up an initial list of the required amounts of chemicals based on intuition and experience, and then produced a final list after repetition of trial manufacture, assessment and modification. In this paper, we propose a mathematical model of transmittance using Beer-Lambert's approximate equation and the Hopfield Neural Network, which was modified to apply to real values. We defined the energy function as the square of the difference between desired and calculated transmittances. Moreover, we avoided the influences of the local minima by adding an annealing method to the network, and achieved exceIlent results.

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This paper deals with optimization of pipe-support allocation using the neural network algorithm of the Boltzmann Machine, and shows the feasibility of the optimization method to actual design problems and also the convergence characteristics of optimization calculation with respect to two parameters such as the Lagrange multiplier and network temperature used. The pipe in question was modeled as a mass-spring mulidegree-of-freedom system and the support was as a spring-damper. The support allocation problem was formulated for the Boltzmann Machine to be utilized to minimize the response of the piping system to earthquake-like random excitation. We obtained the within 5% best solution among about 10 000 cases of support allocation by using the Boltzann Machine algorithm for each case of the piping systems with 5 to 10 degrees-of-freedom.

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Motion of the adaptive truss brings about a change in its geometry and mechanical properties, and it is evaluated from multiple aspects. Some aspects are definite and mathematical, while others are hazy or indefinite. They conflict, in general, and the overall criterion is the result of a compromise among them. Although definition of the overall criterion is critical in motion planning of the adaptive truss, the manner of compromise to define it is vague and is conventionally accomplished through intuition. This article discusses criterion acquisition for optimal motion planning by means of the multilayered neural network. The modular representation of the required neural network is proposed by paying attention to the multiple aspects of evaluation of the motion and the structural formation of the adaptive truss. The feasibility of the proposed approach is demonstrated through simulational case studies.

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There has been no effective study conducted on vibration control of a distributed system such as a shell structure. However, it is possible to exercise accurate control of the shell structure using fuzzy control which does not require a numerical formula in its system presentation. In this paper, a conical shell with variable dampers subjected to dynamic forces is presented. The structure is shaking due to forced vibration caused by seismic motion, then vibration control applying fuzzy theory is carried out. The damping ratios are adjusted by fuzzy control, and displacements and stresses of the structure are reduced. Therefore the validity of fuzzy control of a shell structure subjected to dynamic forces is proved. Further, effects of responses under the different inference methods applied are discussed, and results of fuzzy control of a mass system which is a multi-degree-of-freedom system subjcted to dynamic forces are documented.

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The performance of a damping-controllable dynamic damper was investigated with an adaptive neural net control system. The damping controllability of the dynamic damper was accomplished by introducing the Electro-Rheological (ER) fluid, which is known as one of the highly functional materials and whose apparent viscosity can be varied in accordance with applied electric field strength in a wide range as well as in a short time. As a control system for the present dynamic damper, an adaptive neural net control system was developed ; it was composed of a forward model network and a controller network. With the proposed neural net control system, the damping-controllable dynamic damper can be tuned by itself even if response of a structure shows nonlinearity to input disturbances or varies its own dynamic characteristic. Moreover, the vibration amplitude corresponding to several natural frequencies can be reduced with only a single dynamic damper. Numerical and experimental investigations were performed, and the results shows the superiority of the present adaptive vibration control system.

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In this paper an active control method of a dynamic vibration absorber is presented by applying a neural network model with a known nonlinear structure. The control object is a single-degree-of-freedom system and quadratic and nonquadratic forms are adopted for a criterion function of the optimal control. The design procedure of optimal control consists of an identification mode and synthesis mode, and as a result an optimal nonlinear control is obtained. In computer simulation and experiment the usefulness of the present method was verified.

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This paper discusses the possibility of utilizing neural networks in active vibration control of structures by numerical simulation. The vibration responses of the structure induced by wind force and seismic force are simulated using the multi-degrees-of-freedom beam model. The feedback loop of the vibration control system provides a neural network which has acquired the structural vibration characteristics through learning. We focused on the capability of the neural networks in obtaining vibration characteristics during the learning process, and discuss their possibilities as regards vibration control systems.

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The stability analysis of fuzzy systems is discussed in accordance with the definition of stability in the sense of Lyapunov. The main disadvantage of Lyapunov's stability criterion is that it gives only the sufficient conditions for stability, not the necessary conditions. Furthermore, there are no unique methods of determining Lyapunov functions for a wide class of systems. The purpose of this paper is to propose a construction procedure of Lyapunov functions for a class of fuzzy systems. First, we discuss stability analysis of fuzzy systems using Lyapunov's direct method. A sufficient for ensuring stability of fuzzy systems is obtained. Secondly, two conditions which are used for finding Lyapunov functions are derived : a necessary condition and a ncessary and sufficient condition for ensuring existence of Lyapunov functions. Finally, the effectiveness of this procedure is verified by some examples.

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Recently fuzzy control has been applied to various systems such as home electronics, the process, and plants. Because applications to actual control systems can be risky, the stability of fuzzy costrol system must be insured. As stability analysis of fuzzy control, phase plane analysis, Hurwitz's analysis in subareas, and Lyapunov's method have been proposed. In this paper, we propose a new method of stability analysis, that is, stability discrimination on the basis of display of the stability area in 3D space, the manipulated variable, the control error, and the deviation of its error.

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We present a new learning control method to control a multi-input-output system. In conventional learning controllers using a neural network, it is difficult to treat a multi-input-output system because of the difficulty in designing reference models. Hence, we propose to divide a complex plant into sub-plants and to use a learning controller for each one. We use our method to the regulation problem of the inverted pendulum that is a one-input, two-output system. In the simulation and the experimental system, we regulate the inverted pendulum and show the effectiveness of this method. We also show that our learning control system can regulate a system that has a time lag between the input and the output signals. Moreover, we show that a reference model of order lower than the plant order is available.

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A new control scheme is proposed in this paper which can cope with environmental variations resulting from load disturbances, changes in plant dynamics, and failure of components. The objective of this paper is to blend numeric-symbolic conversion techniques with linear conventional controllers so as to adapt to the environmental variations of the system. The control scheme is based on the parametrization of stabilizing controllers, which is called Kucera/Yula parametrization. The parametrization has been extended to the class of systems which contain numeric-symbolic converters. A neural network with a backpropagation training rule is used as the numeric-symbolic converter. It is shown how the numeric-symbolic converters can be blended with the linear controllers.

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Fuzzy control was applied to container crane to reduce the residual sway and to improve the positioning of a container. Fuzzy rules were modelled on the know-how of skillful operators, which were obtained by observing the actual loading and unloading operation of containers. The results of computer simulation test show that the remaining sway of a container was within ±50 mm and the positioning error was less than 30 mm, with which the actual field test agreed very well. Thus we achieved the anti-sway-system of the container crane with human skill by fuzzy control.

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This paper deals with the forecast-learning fuzzy drive control of an autonomous mobile robot, modelled on human motion. The robot encounters many road situations which are changed according to positions of walls or the existence of obstacles. Therefore, the driving control rules must adapt to numerous situations. Thus, it is difficult to program the robot to adapt to so many situations. In this paper, we propose a new method, the forecast-learning fuzzy drive control, which adjusts parameters of consequent rules, selected by using results of predictions. We show the experimental results of driving an autonomous mobile robot on a straight road with some obstacles.

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On the assumption that the neutral surface of the bending shifts toward a stiffer side in unsymmetrically laminated composite plates, a thin plate bending model is generated without using the coupling stiffness. And a new finite element for eigenvalue analysis of these composite plates is formulated. As a result of numerical works, the natural frequencies and modal shapes of unsymmetrically laminated FRP square plates are obtained. A shaking test using fixed CFRP rectangular plates is performed. The experimental results are compared with the analytical ones by the proposed method. Each results agrees well with one another.

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A hybrid active dynamic vibration absorber possessing such a structure that it is supported by a passive dynamic vibration absorber is proposed in this paper for high-rise buildings subjected to large earthquake. Furthermore, a hybrid dynamic vibration absorber with a switching mechanism of the parameters of passive supporting part is devised to maintain a certain performance of vibration control in a large earthquake. In the computer simulations using a wave with the maximum acceleration of 200 gal, similar to the E1 Centro earthquake wave, the proposed hybrid active dynamic vibration absorbers were compared to the ordinary passive or active type. As a result, the usefulness of the proposed hybrid active vibration absorber was verified even for a large earthquake.

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An end thrust causes dynamic instability of flexible space structures. The sructure is modeled as a free-free uniform beam under a compressive follower force. The stabilization of the beam by means of an active control is investigated theoretically The control force is derived by the torque produced by a pair of tendons attached to the beam. The problem is solved by the Galerkin method in conjunction with the optimal regulator theory. The effects of the location. length and arm mass of the tendon on the stabilization of the beam are clarified through numerical simulation.

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A design method for a multiinput, multioutput (MIMO) microvibration control method is proposed, based on the model matching method, to provide single-input, single-output systems with almost the same control performance as a sky-hook system by using feedback of absolute acceleration alone. In the method, the system is divided into decoupled modal systems, and the control system for each modal system is designed independently. Simulation studies are carried out for two types of MIMO system with force actuators and displacement actuators, showing the effectiveness of the method and the control systems in isolation performance against micro floor motion, damping performance against direct disturbance, and robustness against parameter variation.

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This paper proposes a method for controlling vibrations of a magnetic levitation table. The system considered in this paper is composed of permanent magnet and a permanent magnet with an electromagnet. The vibration is controlled by changing magnetic flux density of the permanent magnet by controlling electrical current in a coil of the electromagnet. Two kinds of control techniques are combined. One is the disturbance cancellation control in which the variation of the levitation force is controlled, which corresponds to the external force due to disturbances, and the other is the state feedback control. Experimental tests have been carried out to discuss the validity of this technique. The experimental results show that the technique proposed in this paper is applicable to isolate vibrations, and the transmissibility can be controlled to be nearly zero.

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This paper deals with control methods and the stability of synchronized active control for machinery vibration isolation. It shows that the instability of the coupled control of the multi actuator system is caused by changes in the sensitivity of sensors, gains of actuators and the natural frequencies of the system. To adapt the system to these changes, the modal control method for the rigid body mode of the machine is proposed, through which the transfer functions between the control signals and the residual vibrations can be obtained by one excitation of actuators. The instability of the coupled control and the effectiveness of the modal control are demonstrated experimentally, using a machinery model supported by 4 piezoelectric actuators. Furthermore, applicable frequency ranges of the modal control, coupled control and independnt control of each actuator are clarified by calculating the convergence properties of the experimental model.

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A series of studies were conducted for the purpose of developing the control system of a shield tunneling machine. First of all, an experiment was performed to examine a model of the movement of the machine in soil. This model was also checked by real excavating data. Using this model the characteristics of the movement were expressed in state equations and a state feedback system was created. The optimum system was designed using the pole assignment method with the state equations. Furthermore, this system was tested on a real construction project. From these investigations, the moving characteristics of the shield tunneling machine in soil were clarified, and it was confirmed that the control system operated satisfactorily. In this paper, the experiment and the design of the control system were described.

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A rotary type compressor used for air conditioning has been developed to satisfy very low vibration and noise level requirements. This paper describes the design technique for reduction of vibration and noise. Since vibrations in the compressor are mainly rotor unbalance vibrations due to the eccentricity of the rotary piston and the rotor bending flexibility, three plane balancing method is introduced instead of conventional two plane balancing method. The introduced balancing method is very effective even if bearing conditions vary. Owning to the 3 plane balancing, the developed compressor vibrations are successfully suppressed by 40% compared to the current compressor type. Noise reduction is also discussed with respect to silencer configurations installed in a compressed gas charge room. A new silencer structure is carefully designed with consideration of acoustic vibration mode shape of the room. According to the increase of the insertion loss of the silencer, the noise extremely reduced by-11dB compared with current type of compressor.

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The characteristics of floor reaction forces are investigated using two large force plates in the three phases of human gait, that is, initiation, stopping and turning, The time histories of the point of application and the center of the body mass in gait initiation and stopping are obtained. In gait initiation, the phenomena of inverse fluctuation are noticed not only in the point of application, but in the floor reaction forces as well. It becomes clear experimentally that inverse fluctuations occur when a person initiates walking. The following results are also described: gait stopping is roughly similar to the time-reverse motion of the gait initiation; gait turning is the continuous motion of gait stopping and gait initiation.

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A robot under end-point force control may often exhibit unstable behavior upon contact with the environment. To avoid these dynamic problems, control gains are reduced until stable behavior is obtained. In this paper, the force control of robot manipulators is analyzed in consideration of the flexibility of the driving system. The influence of the working posture and the flexibility of a sensor and joint driving systems is discussed from the viewpoint of the stability limit of force gain and the eigenvalue loci of the closed-loop system. Some interesting relations between the behavior of the closed-loop eigenvalues and the stability limit of force gain are presented. Moreover, the effectiveness of torque feedback in the force control is shown experimentally and theoretically.

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This paper deals with a kind of micromachine based on a polymer gel actuator system. The polymer actuator has many merits in comparison with other actuators. ( 1 ) It is flexible because it is a polymer material. ( 2 ) It is light in weight. ( 3 ) It is easy to make into an arbitrary shape. Among the polymer gel actuators, we propose a micropump using a thermoresponsive polymer gel. This micropump consists of two one-way valves which make use of a high-water-absorbing polymer gel as a blocking ball. The overall size of this micropump prototype is 8 mm in diameter and 14.5 mm in length. Its weight is 3.2 g. A polymer gel actuator is constituted of the poly (vinyl methyl ether) static polymer (PVME). The mechanism of this micropump is as follows. ( 1 ) By heating the PVME, the gel shrinks. Then the volume of the pump chamber increases, resulting in the inflow of liquid from the inlet to the chamber. ( 2 ) By cooling the PVME, the gel swells in the water. Then the volume of the pump chamber decreases resulting the liquid flow the chamber to the outlet. ( 3 ) By repeating the heating and cooling processes, the micropump provides liquid flow from the inlet to the outlet. The micropump was tested, replacing heating by a nichrome wire with electric current, and showed satisfactory responses.

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An investigation of sound generated from a ball screw was carried out in order to obtain basic information on the sound reduction of a ball screw. In this paper, the sound generated from the ball screw, which prevens pulse sound from occurring, is investigated to clarify the fundamental characteristics and generating mechanism of this sound. It can be inferred from the case of ball bearings that the waviness on the flank is a cause of the sound in the case of ball screws. Thus, the test ball screws made by two flank finishing methods were investigated. The waviness on the flank of the screw shaft and the sound pressure level were measured and analyzed to reveal the relation between the sound and the waviness. From the experimental results and considerations, the fundamental characteristics and generating mechanism of the sound caused by the waviness on the flank of the screw shaft were clarified.

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An investigation was carried out to elucidate the nature of the natural vibrations on the outer ring itself of the tapered roller bearing. In this paper, the vibrations of seven outer rings of the tapered roller bearing were studied. In the experiments, the outer ring itself was struck in the radial or the axial direction. The sound generated by the strike was measured by a condenser microphone. Natural frequencies of the outer ring itself were determined from the frequency spectra of the sound. Moreover, a theoretical approach was taken toward the measured natural frequencies. From the experiments, analysis and considerations, the natural vibrations on the outer ring itself of the tapered roller bearing were clarified, and it was found that the frequencies of the natural vibrations could be calculated by extending the theory of Kirkhope et al.

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The authors developed an expander for a helium liquefier of 100 1/h liquefaction capacity used for a superconducting generator. This paper focuses on the development of the shaft-bearing system, which uses a thrust bearing exerting significant influence on the reliability of the turbine. An externally pressurized thrust bearing was used to support the high thrust load resulting from the high expansion ratio of the turbine. The characteristics of the bearing were estimated based on analytical solution of the theory of complex velocity potential. Good agreement was found between theoretical and experimental results and the practicality of the design method was verified.

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Static friction characteristic improvement in boundary lubrication is attempted by applying D. C. voltage between contact surfaces. The effect of applied D. C. voltage is not obvious in the contact of same materials, where the sliding element and the guide surface materials are the same. On the contrary, the effect of applied D. C. voltage becomes remarkable in the contact of different materials. Adsorbed lubricant film thickness increases, and the static friction characteristic is improved by applying D. C. voltage, in the application where the sliding element is connected to a positive pole and the guide surface is connected to a negative pole. Improvement by D. C. voltage application is remarkable in the contact of rough surface topography.

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A new approach to the thermal elastothydrodynamic lubrication (TEHL) in line contacts is described. The thermal Reynolds equation and the energy equation are derived for basic equations in which temperature distribution in the oil film is assumed as quadratic in the direction of film thickness and the lubricant is treated as Newtonian. By introducing a nondimensional parameter y, the thermal Reynolds equation can be expressed in very simple forms. In the energy equation, four terms, viscous heating, compressive heating, conduction cooling and convection cooling, are involved. Surface temperature distribution is also considered.

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Basic equations for the thermal elastohydrodynamic lubrication (TEHL) in line contacts were described in the 1st report. By introducing a nondimensional parameter y, the thermal Reynolds equation and energy equation can be expressed in very simple forms. Using these equations, TEHL problems can be solved by the Newton-Raphson method, which is the same as isothermal EHL. The only difference from the isothermal problem is that partial differential coefficients are the function of the parameter y, that is a function of the energy equation. Calculated results of pressure, temperature, film thickness and traction coefficients are shown and discussed. From the conclusions, thhe method described here is very useful and in the case of a large slip ratio, compressive heating and convection cooling terms are negligible.

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The behavior of elastohydrodynamic lubrication (EHL) films formed between a steel ball and an oscillating glass disk is examined by means of the optical interferometry technique, and the results obtained are compared with those of tests conducted under unidirectional conditions. The surface traction is also measured. The film profile in the contact area breathes cyclically because the wedging and squeezing actions are not in phase. In reciprocation under pure sliding, the thick oil film entrapped between both surfaces at the stroke end moves towards the exit side at about half the velocity of the glass disk. Under conditions of a short stroke and a high frequency, air bubbles produced in the downstream result in the oil starvation in the next stroke, so that the EHL film collapses. In the full EHL regime, the central oil film thickness and the surface traction at the stroke center are almost the same as those under unidirectional conditions. It is also found that the oil behaves like a non-Newtonian fluid, and as a result the behavior of EHL films varies with oil and type of motion.

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In this study, the generalized modified Reynolds equation governing non-Newtonian fluid film lubrication is derived by considering the fluid inertia effect in the cases of both the Cartesian coordinates and polar coordinates. In the derivation of a modified Reynolds equation, the fluid inertia terms in the euqations of motion for the thin film are averaged over the film thickness, and the concept of an equivalent pressure gradient is introduced to simplify the procedure of analysis. Moreover, in the constituive equation, the apparent viscosity, as a general function of equivalent shear stress, is introduced to express the relation between shear rate and shear stress, and then some empirical models for the apparent viscosity, such as the power law model, Eyring model and Rabinowitsch model, are examined as practical models. The generalized modified Reynolds equation is applied to the infinitely short journal bearings, and the analytical solution for the pressure distribution is obtained.

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Neural network is applied to estimate the durability of a high-speed cutting tool for stainless steel. The lifetime of the tool is categorized into three conditions : 'good cutting condition', 'forced cutting condition' and 'end of tool lifetime'. The vibration data for classifying into the three cutting conditions are obtained from an acceleration sensor attached to the tool. These vibration data are transformed into power spectrum data by FFT. The neural network used in this study is constructed using three layers of processing units. Three typical patterns of the power spectrum data according to the three cutting conditions are used to train the neural network. The performance of the neural network in classifying into the three cutting conditions is tested by applying the power spectrum data for every sample. The experimental results show that the neural network is capable of estimating the lifetime condition of the cutting tool.

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A new method is proposed to predict the thermal deformation of machine tools based on the temperature distributions of the machine by introducing a neural network model. The relative thermal displacement between the tool and the workpiece of a vertical machining center due to the rotation of the spindle is predicted by applying the neural network with three layers of input, hidden and output layers, after several learning processes. It is shown through the experiments that the relative thermal displacements in the Y and Z axes and also the inclination of the spindle in the Y-Z plane are well predicted by the method proposed.

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In this paper a simple analysis method, the equivalent, sublink method, is proposed for thhe position analysis of the strongly coupled loops in a lower-pair mechanism. Compared with previous methods, a nonlinear, single-variable equation can be deduced by this method, and a more precise solution of the position analysis of linkages can be obtained rapidly. The basic principle and a practical example of such a method are introduced with demonstration of the analysis of the six-bar mechanism.

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In order to develop a simulation program for control of truck cranes and aerial devices, we evaluate the dynamic responses of truck cranes in operation. The boom structure is approximated by beam elements with three masses, and the set of equations expressing nonlinear second-order models is derived by the Lagrange equations for the dynamic analysis of booms and a winch. The dynamic responses of the truck cranes in operation are numerically evaluated by the Runge-Kutta-Gill method.

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This paper concerns the design method for the controller of structures arranged in parallel. In the case of vibration control for 1DOF-1DOF model structures, the authors previously proposed the method of vibration control to individual structures without addition of mass like active dynamic absorbers. This paper shows the design method for a controller of 1DOF-1DOF parallel structures by the LQ theory. First, the relationship between dimensional and nondimensional parameters in the LQ theory can be determined by the similarity law. The characteristics of the controller are then analyzed, and from this, it is easy to design dimensional parameters of the controller. Subsequently, it is demonstrated that there is an optimal weight matrix for the characteristics of the controller, and this optimal weight matrix and its roots are analyzed. Furthermore, the influence of structural parameters to vibration control is shown by simulation. It is demonstrated theoretically that this method is effective for the design of 1DOF-1DOF parallel structures.

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This paper presents a two-dimensional dynamic analysis and experiments on the human hand-arm system with various configurations under strong and weak gripped conditions, subjected to sinusoidal acceleration. The direct integration method is adopted, and joint spring and damping parameters have been determined by partial optimization technique with a least squares approach, in which the discrepancy between the theoretical and the observed is iteratively corrected in a multistep manner so that at first the gap for wrist responses is minimized, then followed by the gap for the elbow, and finally the gap for the shoulder. Finally, a more simplified model for the hand-arm system with reduced joint parameters is proposed and its adequacy is verified through simulation. It is shown that the spring and damper of each joint do not depend on their shape configuration, and that phase, response and joint parameter are strongly influenced by the grip condition.

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The present research is about designing straight path control for a 2DW1C-Type tri-car mobile robot. At the beginning of a position feedback control system is designed with the actual position surveyed by external sensor. The purpose of this paper is to clarify the relationship of each feedback gain corresponding to each position error to the system's stability and positioning characteristics. As a result of step resonance and running simulation on real road conditions, the analysis confirms the system's stability. Results of this research can be adapted any optional path by dotting desired path.

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In this paper, we study the moving mechanism of a wall surface mobile robot for hazard maintenance under gravity. This robot can cling on a vertical wall or ceiling by vacuum pads. The vacuum pads are set on the crawler so as to enable rapid mobility on the surface. Each vacuum pad is simply designed. There is a mechanical valve set at each sucker and every sucker is connected with an air duct inside the crawler belt. The valve opens mechanically when the sucker touches the surface, and the sucker clings to the surface. By this mechanism, the sucking control system becomes simple. The vacuum pad is made of flexible material in order to assure a sufficient sucking force even when the surface is rough. This robot also has an automatic pushing mechanism for the suckers and distribution mechanism. We designed, made and tested the prototype. In the experiment, this robot succeeded in climbing smoothly and rapidly on the surface of a vertical wall and ceiling, on both rough and smooth finishes.

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In this second paper, the effect of finite width on the hybrid performance of externally pressurized foil bearings with a porous shaft is examined theoretically by considering the roughness effect of the foil surface. Based on Patir and Cheng's theory, the two-dimensional modified Reynolds equation and force-balance equation for the foil are solved iteratively by the finite-element technique, and the numerical solutions for pressure and gap height are obtained under the various combinations of bearing width-to-diameter ratio, dimensionless wrap angle of foil and dimensionless roughness height. From the numerical results, the combined effect of finite width and surface roughness on the pressure and gap height in externally pressurized foil bearings with a porous shaft is clarified.

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This paper presents a new differential method called the mixed method, which was developed to measure the profile accurately under the circumstances of on-machine measurement. In comparison with the 2-point method, this method can more remarkably reduce the datum errors due to scanning, vibration and thermal drift. This method also has the advantage of obtaining the high-frequency component of profiles accurately. An optical sensor was designed and made to realize both the 2-point method and the mixed method. With a modulation technique, the sensor has a good thermal drift characteristic. It can measure the displacement and angle of two points on a mirror surface simultaneously with a resolution hither than 0.1 μm and 1 second. Using this sensor, an on-machine measurement system has been constructed, and the measurements of the straightness of cylindrical mirrors have been attempted with the 2-point method and the mixed method. Comparing the results, the favorable characteristics of the mixed method have been confirmed.

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The purpose of this study is to elucidate the root cause of a change of the grinding force ratio, which is the ratio of the tangential force and the radial force. In the grinding tests of this study, the interference shape per cutting edge and the state of the cutting surface of the wheel were changed systematically. The following results were obtained: ( 1 ) When the state of the cutting surface of the wheel and the peripheral wheel speed are held constant, the product of the interference length and the maximum interference depth per cutting edge of abrasive grain decides the grinding force ratio. ( 2 ) The grinding force ratio shows a rise with the increase of successive cutting edge spacing, and the increase of the rate of the area of grain flank reduces the grinding force ratio. ( 3 ) The grinding force ratio in a series of experiments is decided by the quotient of the product of values of interference condition per cutting edge and the rate of area of grain flank in the cutting surface of the wheel.

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Mechanical properties under uniaxial and equi-biaxial tensions are examined for electronic copper foils and sheets ranging from 5 μm to 1 mm in thickness. A hydraulic microbulge test is proposed for the equi-biaxial tension applicable to very thin metal foils, and its validity is confirmed by computer simulation based on the Bassani yield function. The yield stresses in both the uniaxial and equi-biaxial tests are dependent on the grain size, but not on thickness. The conventional yield criteria are shown to be applicable even to very thin foils as well as to sheets with usual thickness. However, the fracture mechanism varies according to the thickness, and thus, the limit strain and ductility of foils become markedly low.

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