Rolling noise arises from the interaction of the vibration characteristics of rails and railway vehicle wheels through the points of contact. This paper deals with the coupled linear vibration between wheels and a rail using an approximate model with an infinite number of vehicles which are arranged with a certain, periodicity on an infinitely long and straight rail installed on three distributed springs, taking the coupling in both vertical and horizontal directions into account. The vertical irregularity on the head surface of the rail is regarded as a source of excitation. As a result, it was clarified that ( 1 ) the vertical vibration of the rail, the horizontal ones of Wheel and rail, and the vertical one of the wheel contribute to the rolling noise according to high vibration level, and ( 2 )the vibration levels are high on the tail within the narrow intervals between wheels.

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A numerical computational method is suggested for the nonlinear analysis of a piecewise linear system including a system with clearances which is often found in practical mechanical structures. When this method is combined with the analytical method for the nonlinear system based on the concept of harmonic balance, the piecewise linear system is analyzed with high accuracy. The validity of the incremental transfer influence coefficient method formulated in the previous report for the structure connected in series is verified by the numerical computational results for some examples, as compared with those of the incremental harmonic balance method and the incremental transfer matrix method. As a result, it was confirmed that the incremental transfer influence coefficient method was the most effective among the three methods as the degrees of freedom of the structure treated become large and the accuracy of an approximate solution becomes high.

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When high-speed and lightweight rotors in jet engines or turbopumps used in space vehicles are subjected to base excitation such as turning or pitching motion, the rotors may be brought into contact with the casing, or the bearings may be damaged due to the vibration caused by gyroscopic moment or centrifugal force. In this paper, a dynamic analysis of a rotor system that comprises flexible suspensions, a flexible shaft, a flexible disk and flexible blades is performed by a finite-element method. The rotor is excited by a pitching motion of the frame, of which the axis is assumed to be distant from the center of mass of the rotor. The usefulness of modeling and the validity of the computational program are demonstrated by comparison with the experimental results obtained using a model rotor. The dynamic response of the system in the case of the turning motion of the frame is also calculated.

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In the field, the vibration caused by the unbalanced force is sometimes a serious problem, though the imbalance of the rotating and reciprocating parts, such as crank shaft, piston and connecting rod, is reduced by means of a weight control or a dynamic balancing. This vibration problem is often caused by the various devices which are attached to the rotating part of the engine at the field. A method to reduce the unbalanced force at the field has been required. A field balancing technique is used for reducing the unbalanced force in an electric motor system or a generator system. It is difficult to apply this method to the engine, because of a 1st-order rolling moment remained in the reciprocating engine. A new field balancing technique is developed considering the 1st-order rolling moment. Using this technique, the unbalanced force is identified without the effect of the rolling moment.

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This paper deals with a mathematical model of the mechanics of rigid bodies connected by rotary joints. The method is based on the Lagrangian formulation. The kinetic energy is written in terms of the angular velocities. The expression for the kinetic energy has a homogeneous quadratic form in the angular velocity, the coefficient matrix of which is given by the products of triangular matrices. The equations of motion are derived from the Lagrange's equations for the quasi-coordinates, the angular velocities of the bodies. The equations of motion become recursive forms due to the structure of the expression of the kinetic energy of the system. The algorithm of the inverse dynamics, which follows from the equations of motion, becomes also a recursive form like the algorithm based on the Newton-Euler equations of motion. Since the algorithm is based on the Lagrangian formulation, it can be extended to more complex systems that include flexible bodies, the constraints of which limit the motion of the systems, and so on.

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Generally, readjusting the control system is necessary for the servomechanism when the load is changed, and the automatization of the controller is important for the servomechanism. This paper describes the estimation method of the inertia term and the automatic tuning system using this estimate. Firstly, we propose the estimation method of the inertia term using the disturbance observer. In this method, we make use of the characteristic that the estimate error of the inertia term has an effect on the disturbance estimate. The estimate error can be obtained by integrating the disturbance estimate between some specified intervals. Therefore, the new estimate of the inertia term is obtained by adding the estimate error to the inertia term value being obtained. Secondly, we try to apply the above-mentioned method to the feedforward compensation of the inertia force and the disturbance torque compensation for the automatic tuning. A cyclic test signal is prepared in order to estimate the inertia term and the proposed method is applied after one cycle motion has been completed. The obtained inertia value is used for renewing the inertia term of the feedforward compensator and the disturbance observer. As a result, the actuator can operate more accurately at the following motion. The effectiveness of this method is demonstrated in the experimental results.

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A method in evaluating simultaneous structural, control, and shape optimization of large lattice-type flexible structures is presented in this paper. Two different and mutually conflicting criteria, the structural weight and the control energy to reduce vibration, are taken as objective functions. With the help of continuum modelling, geometrical shape optimization of structure including the number of nodes and the connecting members is carried out for a long, slender lattice tower, the dynamic characteristics of which are determined economically with the help of the reduced order equivalent beam model.

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The authors propose a method to design the optimum control system toward flexible structural systems. The mechanical structural system can be modelled by identifying the spatial matrices from experimental frequency response functions. The optimum control system is easily designed by applying the optimum control theory to the identified system. However, the stability of the control system is not always guaranteed because the mechanical system is generally identified with small degrees of freedom ignoring high-order modes. This report proposes an optimization method of the control system which guarantees the stability of the actual system which is also an identified system with high degrees of freedom. The characteristics of both the identified and actual system are simultaneously optimized by the proposed method based on sensitivity analysis and nonlinear programming. An experimental example verifies the effectiveness of the proposed method.

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There are many proposed control methods that are intended to achieve more marked ride comfort in vehicle suspension systems. In these control methods, a strict trade-off between human sensitiveness and vehicle attitude exists and it is quite important to choose the kinds of performance indexes for vibration control. Aiming at improvement in both ride comfort and vehicle attitude characteristics, frequency shaped-functionals are applied to suspension control systems. As a result of the study, marked improvement in performance is confirmed by both simulation and experimental studies.

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This paper describes a vibrationless access control which is robust for parameter variations. It is important for the vibrationless access control of a positioning mechanism with mechanical flexibility to eliminate residual vibration at a target position even if natural frequencies of the mechanism vary. From the relation between the residual vibration amplitude and the frequency spectrum of feedforward control force, it is found that the control force can be robust for the natural frequency variations if the control force has no frequency component within the range of varying natural frequencies. In the proposed method, an enlarged system is first constructed in the modal coordinates for a virtual mechanism which has a few natural frequencies within the varying range of the concerned natural frequency. The optimal control theory is next applied to the enlarged system and the vibrationless feedforward control force is calculated. The improved robustness of the proposed vibrationless access control is demonstrated with experimental results.

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The flow-induced noise generated by high-speed rotating machine components, such as a polygon mirror of a laser printer, is analysed both in experiments using sound intensity measurement with two microphones and in finite-element flow analyses. The results of sound intensity measurement reveal the effect of beveling on the edge of the mirror in order to reduce the noise. The numerical prediction of the sound field around the mirror has been carried out. The fluid flow around the mirror is modeled mathematically and analysed using the two-dimensional Navier-Stokes equations and the finite-element method. The predictions based on the finite-element analysis show good agreement with experimental results, promising an effective tool in designing the shape of high-speed rotating machine components for noise reduction.

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This paper proposes a method of estimating the sound pressure of structureborne sound included in noise radiated by an enclosure housing a machine that produces both noise and vibration. In this method, estimation is carried out without any change in the condition of installation of the machine using accelerations measured when the machine is in operation and frequency-response functions determined when the machine stops its operation. First, the theory of this method is briefly introduced. The frequency-response functions are determined by exciting multiple points on a machine housed in an enclosure. Then this method is tested using an experimental setup in which the enclosure houses an excitor and a speaker. It is shown that the estimated results agree well with the measured results. Finally, the error in the estimation is discussed.

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According to the trend of giving high performance to construction machinery, designers have been attaching larger and heavier arm structures than the current type. But such design policy causes an instability problem in the entire body, caused especially by arm vibration in the low-frequency range of 2 to 3 Hz, and it is very difficult to control this vibration by passive techniques. This vibration has had to be ruduced substantially to prevent harm to the operator. This paper deals with a modal synthesis of arm vibration, a mathematical modelling of an active control system involving hydraulics, and a linear simulation using a LQG (linear quadratic gaussian) control method.

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According to the trend of giving high quality to construction machinery, designers are being required to improve the tonal impression of this machinery, as well as cars and air conditioners. However, it is very difficult to determine tonal impression due to the lack of sensory scalings. In particular, this machinery has several sound sources, i. e., engines, fans and so on, so exterior sound has a complex tonal construction. This paper deals with a dimensional analysis of tonal elements, and a quantitative evaluation method based on tonal elements.

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According to the trend of giving high quality to construction machinery, improvement of riding comfort has recently been highlighted. However cab system, which is mounted on supporting structure by rubber, has inevitable vibration problem in low frequency range below 20 Hz. Especially its natural rolling mode about 10 Hz hurts riding comfort of operator, and this mode has been required to reduce as possible. This paper deals with a modal synthesis of troublesome rolling vibration, and a application of TMD (Tuned Mass Damper), designed by the information of system identification.

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This paper deals with the mathematical modeling (by FEM) and experimental analysis of a 2-dimensional single-link flexible manipulator with rotational and translational degrees of freedom. Dynamic response calculated by numerical analysis and verified by experiments revealed that the torque required at the hub and the vibration of the tip to which the pay load is attached can be reduced significantly by the translational movement of the arm due to better distribution of the moment of inertia of the whole system at the time of carrying a pay load from the starting point to the destination point.

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In this paper, we present a new scheme for intelligent control of robotic manipulators. This scheme is an integrated approach of the Neuromorphic and Symbolic control, including the applied neural network for the servo control and the knowledge-based approximation. The neural network in the servo level is the numerical manipulation, while the knowledge-based part is the symbolic manipulation. In Neuromorphic Control, the neural network compensates the nonlinearity of the system and the uncertainty in environment. The knowledge-base part forms symbolic control strategy for the servo level. This is control system analogous to the human cerebral control structure.

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In previous research we confirmed the effectiveness of the heuristic method to control a brachiation robot (BMR) that we have been proposed, and also we proposed a method using spline interpolation to get suitable driving inputs for unexperienced targets deriving from already experienced ones. In this paper to get driving inputs in case of multiple changes of control situations we use CMAC neural model to interpolate driving inputs got from experiences. And to achieve precise rudder-catching we use trajectory feedback control and arm-direction feedback control.

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This paper deals with the concept of the distributed microrobotic system (DMRS) and experimental results of the microelectrostatic actuator. DMRS is what is applied to the dynamically reconfigurable robotic system (DRRS) to the microrobotic system. DRMS is useful for task execution in a space with a small entrance which is too narrow for the entire robotic system to enter. To realize this concept, we propose the Micro-CEBOT (Micro-Cellular Robotics). We show a prototype of the moving cell with the actuator. As the actuator, we used an electrostatic actuator. It is well known that the electrostatic actuator is more advantageous in a smaller size. We propose a structure of the stacked-type electrostatic actuator (STESA) to produce power. Some experiments are performed to examine the behavior and properties of the STESA.

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Control architecture is an important problem for the distributed intelligent system. We describe on the evaluation of grouping with plural master cells for a cellular robotic system (CEBOT) as one of the group robotic systems. For the evaluation of the grouping, we use network energy as the estimation function, which we have proposed in a previous paper. By describing the grouping of the network with plural master cells as cores in a subnetwork, we represent the effect for the group structure of the organization or the society. Then for the estimation of the grouping of the network, which is organized by autonomous robotic units called "cells, " we propose the cross-dependence matrix in the cells. The matrix is led from the "task matrix, " which represents the relations between the cells and executing task steps. Finally, we show the simulation results for the example of the organized network by the cellular robotic system. This paper also describes mathematically the efficiency of grouping of the orgnization or the society.

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This paper describes the development concept, control methods and experimental results on the stabilization and walking control of a unique biped robot. This walking robot constits of two legs, pivoted upper and lower bodies composed of four basic modules and double controlling arms suspended from the upper body. Each leg forms a single link and its sole is made up of a portion of a sphere. In order to stabilize the posture of the robot, a feedback control method based on the compound center of gravity among the bodies, the controlling arms and the legs was applied. Postural stability of the robot in the pitch and roll directions was realized. Furthermore, we succeeded in producing a walking motion by controlling the legs according to the posture of the robot.

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This second paper shows the full solution to the thermohydrodynamic turbulent lubrication problems including the surface roughness effect. The generalized modified lubrication equation and energy equation, which were newly established in the previous paper, are applied to the full circular journal bearings covered with homogeneous surface roughness. These two equations are solved numerically by combining with the equation for heat transfer to the bearing' bush, in which the shaft surface temperature is calculated by averaging the mean temperature of fluid film over the circumference of the journal. Numerical results for the various kinds of bearing characteristics such as pressure and temperature distributions, Sommerfeld number, attitude angle, friction coefficients and flow rate are presented in graphic form for the suitable combination of Reynolds number and relative roughness, and the temperature rise effects on the bearing characteristics are discussed in detail.

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In this paper, the static characteristics of a new type of aerostatic thrust bearing with a self-controlled restrictor is proposed in order to establish a very high stiffness (nearly infinite stiffness).The self-controlled restrictor used in this bearing makes use of the balance of fluid-film forces acting on both sides of the floating disk to control the gas flow entering a bearing clearance. Since various design parameters influence the static characteristics of the proposed bearing, the effects of these parameters are discussed theoretically and experimentally. Then the optimum design method to obtain higher stiffness is also discussed. It is consequently demonstrated that the proposed bearing can have a very high static stiffness, about ten times as high as that of a conventional aerostatic thrust bearing.

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This paper deals with the cutting mechanism based on cutting tests by 2-tooth end mills with different helix angles. The results are as follows. ( 1 ) There was a chip area decrease by a low helix angle edge and increase by a high helix angle edge, in the cutting process with no transition period in the end milling. ( 2 ) Behavior of the cutting force is coincident to that of chip area. However, in the cutting process except the transition period, the change in the cutting force is larger than that in the chip area. ( 3 ) Under the cutting conditions, the machined surface from the bottom to 5 or 7 mm is generated by a 41°helix edge due to smaller normal force, and the other part is generated by a 38°helix edge in the same manner. ( 4 ) Light and heavy chips are obtained by the 2-tooth end mill, but the chip weight is lighter for the former and heavier for the latter than each ideal value. ( 5 ) On the assumption that a high helix angle edge cuts a workpiece overmuch in the feed direction based on the results of cutting tests, calculated values of chip weight and cutting force agree with experimental values, respectively.

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For better grinding performance, three significant aspects involved, namely, the grinder, the grinding wheel and the grinding fluid, must be improved together and brought to a required level. This paper attempts to clarify the effects of the grinding fluid additives on the grinding performance by using a three-face Makitsuke nozzle which ensured a supply of fluid directly to the grinding point and observing specifically the fracture behavior of abrasives during grinding. As a result, a higher grinding ratio and better surface roughness were obtained with reduced grinding resistance and wheel edge wear.

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Aluminum pipes with mirror surfaces were successfully produced directly from hot-extruded pipe-workpieces by the inside-ironing method newly devised by the authors. A pipe is set in a steel container with very smooth inner surface, and the inside of the pipe is then ironed by a punch. The grooves with a depth of about 1 μm which were formed on the outer surface of the pipe by extrusion are well flattened and completely disappear through the ironing process. The outer surface of the pipe can be finished to a mirror surface as the replica of the inner surface of container. The working conditions to perform the process were also studied. An axial compresive force P_c should be loaded at the upper end of the pipe during the process to prevent it from slipping off against he container. The force can be reduced as the punch semi-angle decreases and/or the friction at the surface of container increases.

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Effects have been investigated of punch diameter, clearance and thickness ratio of components in two-layer-clad materials on punching. Two kinds of clad material produced slightly different tendencies in punching load-time curve and specific shearing stress due to mechanical properties and thickness ratio of components. Specific shearing stress measured was compared with those calculated by law of mixture and double punching method of monolithic materials. The stress calculated by the latter is smaller, however not always closer to the measured value than the former.

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In this paper, correlations between electric discharge machining conditions and output of the AE sensor, which has been developed by one of the authors, are experimentally investigated. In the experiments, while three machining conditions of electric discharge voltage, current and capacitance are varied, peak values of output voltage of the AE signals are measured. From the experimental results, it is found that the peak value of the AE signal is proportional to the second power of the machining voltage and proportional to the capacitance of the condenser. However, the peak value of the AE signal is indenpendent of the discharge current. These relations are in good agreement with the discharge energy.

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This paper describes a procedure for optimizing the route selection and production conditions in alternate process plans under a cellular manufacturing environment. The problem associated with determining the optimal values of the machining speeds, overtime, and intercell flow is formulated as Nonlinear Mixed Integer Programming (NMIP) in order to minimize the total production change cost. This is achieved by introducing the marginal cost analysis into an NMIP, which Will compute the optimal machining speed, overtime, intercell flow, and routing. The application of this procedure offers greater flexibility to take advantage of the cellular manufacturing due to the optimum use of resources. A solution procedure for this problem was developed and a numerical example is included.

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This paper proposes a method for integrating CAD and CAM, in which both maximization of the product performance and minimization of the product manufacturing cost are sought. In order to obtain effectively and efficiently the optimum decision variables for the integrated product design and process design, a method for describing machine-parts shapes is first developed with the main consideration being given to the description of the contact surfaces. Then, a multiphase decision-making method using those data is constructed in which the decision-making process is divided into three phases, and the shapes, materials, and manufacturing methods of machine parts are determined in steps according to multiphase processes. Finally, the proposed methods are applied to designs of an industrial robot for demonstrating the effectiveness of the methods.

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It is not always easy to verify work-piece accuracy determined by the minimum zone method even with long calculation time. Therefore the auther clarified the geometrical condition of straightness in another report. According to the report, when there are two points A, B on a straight line of two parallel lines determined by the minimum zone method, and one point H on the other straight line, the angle of ∠HAB and ∠HBA are smaller than π/2. So, this paper showed a calculation method based on the geometrical condition. The calculation method has the advantage that the true solution is get certainly, the algorithm is very simple and the calculation time is much shorter than the standard method.

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Workpiece accuracy should be evaluated by the minimum zone method. Therefore many techniques were proposed by means of optimization methods. However, it is not always easy to obtain the true solution or approximate value of accuracy even with long calculation time. The true solution exists in the case of the minimum zone method because the solution can be determined theoretically. However, it is not a realistic method because of its calculation time. If the geometrical condition defined by the minimum zone method is clarified, the technique to verify the minimum zone becomes easy. In order to solve this problem, this paper discusses the geometrical condition of the minimum zone straightness.

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In order to display the multi-media information in our factory and office, it is necessary to make clear how an eye sees the scene. In this paper, we propose the method using the queue theory to make clear how to stay an visual point in some area. The visual field is divided into square mesh (2°×2°), and the traffic intensity is calculated in each mesh. And 19 works which have from 2°×2° to 45°×60° visual field are evaluated by the proposed method. It is shown that the visual point mainly moves in 5% area of visual field, and 80% of visual points stay in 2% area of that. As the gazing region becomes small, the traffic intensity becomes high. And the Visual point visits same area repeatedly. The traffic intensity becomes too high in monitor work (0.23-0.30), and decreases gradually in the order of assemble work (0.18), VDT work (0.05-0.17), And it becomes extremly low in walking (0.05 to 0.08).

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This paper proposes a new facility layout method with two phases. In this floor plan placement problem, a placement unit is a block which has various rectangular shapes. In the first phase, the initial block placement is obtained by an attractive and repulsive force method. In the second phase, a quad-tree is constructed by dividing a placement area into four rectangular areas recursively, as long as the area contains two or more block centers. The quad-tree maintains information about topological characteristics contained in the solution of the first phase. Then, a block packing process is performed heuristically by using the quad-tree. The solutions of this method keep global suboptimality. This method allows from the beginning to consider two constraints about floor dimensions and certain blocks specified by their locations on a floor. It is easy to perform manually the algorlithm of the second phase for a fairly large-scale problem. The methodology is presented and demonstrated by some example problems.

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An elastic rotating shaft supported by ball bearings may have nonlinear spring characteristics due to clearance and internal damping due to friction between the shaft and bearings. In such a system, self-excited oscillation appears in the post-critical region. When the relation ω≒±2P_i holds between the rotating speed ω and a natural frequency P_i, a subharmonic oscillation of order 1/2 may appear. The vibration characteristics in the neighborhood of these resonance points are discussed. It is clarified that an entrainment phenomenon appears due to the interplay between the self-excited oscillation and the forced oscillation. As the result, the self-excited oscillation disappears and only the subharmonic oscillation appears in these resonant points.

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Nonlinear behavior of a multirotor system supported by oil film bearings is investigated theoretically by calculating the loci of centers of disks and a journal of the system using a time-marching method. The oil film force of bearings is obtained by solving the Reynolds equation at each time step using a rapid solution presented previously by the authors. It will be shown that a 2-disk/4-bearing rotating system operated under the linear stability limit but above twice the first critical speed becomes unstable when sufficiently large external shocks-an artificial sinusoidal shock and real seismic waves (Taft, California, 1952)-are given to the system. The effect of misalignment of bearings is also examined closely in this study.

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Dynamic interaction between industrial equipment and its supporting frames during earthquakes should be taken into account for earthquake-resistant design of complex industrial structures such as blast furnaces, chemical reactor vessels or towers, certain kinds of stacks, and so on. In the first stage of the current aseismic design of these structures, the maximum base shear transmitted to each component is assumed in advance in order to obtain a precise stress analysis of each one. It is significantly important, therefore, to provide well-grounded base shear distribution in place of the conventional values which are decided via a static analysis at most. This paper aims to examine the effects of dynamic interaction on the base shear distribution between equipment and its supporting frames during earthquakes. The random vibration theory is applied to obtain the average peak responses of simplified interaction models placed on a base which is being stimulated by ground acceleration having the standard power spectrum. The expected maximum values of the rocking moment distribution are obtained as the function of dynamic characteristics of both components and the interaction spring. These results are presented graphically for convenience so as to determine the rational base shear distribution of structures composed of equipment and its supporting framed.

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A torsional dynamic vibration absorber for a crankshaft, which consist of a vibroisolating rubber component and a moment of inertia, is used at relatively high temperature and frequency. It is important to analyze the steady-state response of such a system. The most simplified model consists of shear loading rubber isolator and a mass. We have already suggested an analytical method of the system for which mechanical nonlinearity and heat generation have been taken into consideration. The validity of it has been examined by comparing analytical results directly with experimental ones. In this paper, we give more detailed consideration and clarify the mechanism of the response. The system can be characterized as a system which couples the mechanical nonlinearity, depending on temperature and internal heat generation. As a result, we can derive again the analytical method in the previous report.

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It has often been indicated that oil dampers are affected by the compressibility of oil. If the oil is an incompressible fluid and the oil damper is a viscous damper, then the damping coefficient of the oil damper should be independent of the amplitude and gradually increased with the frequency of the piston. But in practice, the damping properties of most oil dampers are strongly dependent on them; damping force is greatly reduced at high frequency and small amplitude. These phenomena were considered to be the effect of oil compressibility. The conventional expressions for calculating the damping coefficients of the oil dampers, however, are based on the assumption of incompressiblity of oil. As a natural result, the phenomena mentioned above cannot be explained by the conventional expressions. In this paper, we derived a new expression for a viscous oil damper by considering the compressibility of oil. It was obvious from the experimental work that the frequency characteristics of the viscous oil damper were well explained by our expression.

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This paper describes the influence of the guideway surface roughness on the vertical motion of a transport vehicle that has a permanent magnet suspension with mechanical air gap control. The roughness averaging effect of the undercarriage with a longitudinally distributed magnet is evaluated by a two-degree-of freedom (2DOF) model with a filter, which is equivalent to the roughness averaging effect. The results show that the difference in the averaging effect between the wheelbase length of the undercarriage and longitudinally distributed magnet causes the increase of the guide wheel load, and that the suitable magnet length is about 1.6 times the wheelbase length. By a funning simulation, it is also shown that the proposed 2DOF model can express vertical vehicle motion effectively when pitching motion is relatively small.

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Dynamic behaviors of crawler-type vehicles in off-road running are nonlinear phenomena caused by the changeable boundary conditions of the ground, and the rattle of the crawler. Therefore, they are usually analyzed by direct numerical calculation of equations of motion using a rigid body and mass-spring-type model. But in this method, the effect of flexibility is not considered for the frame component of which a vehicle consists. In this paper, an efficient method is proposed, by which most hard behavior can be analyzed on falling impact with the ground when a crawler-type vehicle is running over a bump. This method consists of 2-D rigid-body motion analysis, component mode synthesis, and modal response analysis, and hence it can be applied to a large size model which contains flexible structures. Usefulness of this method in application to a bulldozer is demonstrated by simulation and experiment.

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Automatic transmission (AT) is believed to be the representative transmission for easy drive. Nonetheless, the AT tends to act to increase the number of gear steps of a planetary gear train and is oversized and complicated, including its control system. The compact transmission (RX-AT), an experimental model for automobiles, employing the 3K-type planetary gear CVT, has already been manufactured. In this paper, the combination of torque converter function by cam mechanism and hydraulic control system enables the development of transmission by RX-AT which operates only by accelerator without CPU. Consequently, good performance of automobiles built with this RX-AT has been verified by experiments.

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An actuator with visco-elastic properties is made, which is composed of several mechanical elements, i. e. of magnetic coil, permanent magnet, springs, oil film and so on. Its mechanical properties are compared with those of skeletal muscle. Some good similarities are obtained in length-tension and force-velocity relations and tension response to sudden length change. However, the power/self-weight ratio, contraction speed and energy efficiency are far smaller than those of the muscle. This mainly depends on the performance of power source itself and high viscosity of the oil used. With further improvements of each element, it is possible to develop a mechanical visco-elastic actuator like human skeletal muscle.

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This paper deals with some results of development of the electrostatic microrotational motor : the so-called wobble motor. A rotor of the wobble motor revolves inside a stator with rotation on its own axis. The rotational speed on its own axis is less than the revolutional speed. Then, if the rotational speed can be taken out, this motor develops low-speed, high-torque characteristics. The size of the developed motor is 9 mm in outer diameter and 23 mm in length. The generated static torque of two rotors of different sizes has been analyzed by the boundary element method. The experiment for confirmation of the analyzed results has been carried out, and satisfactory results have been obtained. On the basis of these confirmed theoretical results, the optimal design factors are explained.

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The wringing phenomena of gate blocks were investigated theoretically. A model for the wringing mechanism was proposed. The adhesive force of the wringing is considered as the product of the distance around the oil film between two gage surfaces and the oil surface tension. Since the gage surface is exceedingly smooth, the number of contacts between two gages is great. In that case, the oil film is split finely on the surface and the distance around the film increases noticeably. Hence, large adhesive force is usually experienced. The calculated adhesive forces based on the above model agree with those measured by other investigators.

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In order to obtain fundamental data on the surface durability and surface failure mode of induction-hardened sintered powder metal rollers, rollers made of pre-alloyed powder with diameters 30 and 60 mm were fatigue-tested with case-hardened melted steel rollers under a sliding-rolling contact condition. The experimental results were discussed by the amplitude of the ratio of shear stress to Vickers hardness. The surface failure mode in this experiment was spalling due to subsurface cracking. The depth of the spalling crack agreed well with the depth of the peak amplitude of the ratio of orthogonal shear stress to Vickers hardness. The surface durability tended to increase as the relative radius of curvature decreased. There was an optimum hardened depth for the surface durability. The pores played an important role in the occurrence of cracks.

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This paper proposes new techniques of identifing thermal systems, in which heat transfer from the atmosphere is isolated, and it is verified that the techniques can produce accurate results. The first technique is to obtain a curve fit for the measured temperature history with random error, by using the equation of linear heat flow in a solid bounded by a pair of parallel planes. The second technique is to use a three-columns band matrix for heat conductivity and heat capacity matrices of thermal systems. The third technique is to reduce unknown parameters of heat conductivity and heat capacity matrices by using the thermal characteristic of an isolated structure. The validity of the new techniques is shown by numerical simulation. It is demonstrated in its application that the temperature of a thermal system under varied forced heat flux can be accurately simulated by using the identification under constant forced heat flux.

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The thermal inertia of a machine tool bed made from concrete material is generally much larger than that of conventional ones such as cast iron or steel. Hence, it is considered that the thermal response of a concrete bed depends strongly on the period of fluctuation of ambient temperature. In this paper, the thermal behaviour of a concrete bed in fluctuating ambient temperature is discussed comparing it with that of a conventional cast iron bed. It is verified that a concrete bed has an extreme advantage in the viewpoint of thermal deformation when the period of ambient temperature fluctuation is relatively short.

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Many techniques of optimization methods to verify the minimum zone accuracy have been proposed, but it is not always easy to obtain the true or approximate solution even with long calculation time is expended. Therefore this paper discusses the geometrical condition of flatness and a calculation method based on the geometrical condition. The results are shown below. 1) When there are two points, a, b on one of two parallel planes determined by the minimum zone method and c, d on the other plane, the segments ab and cd projected on one of the parallel planes intersect each other. 2 ) When there is a point H on one of two parallel planes and three points A, B, C on the other plane, the point H projected onto the opposite plane is in ΔABC.

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Workpiece accuracy Should be evaluated by the minimum zone method. Therefore many techniques of optimization methods to verify the minimum zone accuracy have been proposed. But it is not always easy to obtain the true or approximate solution even with long calculation time is expended. Hence, this paper disscuses the geometrical condition of straightness in undetermined directions. Because the geometrical condition of finite data points should be determined by the definition of the minimum zone method, the straightness in undetermind directions is determined by three or four points.

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