The studies of man-machine interface have been researched in many technical fields. This paper presents the way of building human models with considering voluntary muscle contraction. Firstly, methods for evaluating muscular properties during static and dynamic conditions are proposed, and rations of muscular activity of dynamic load to static load are introduced. Secondly, human lower extremity model with muscular system is built and simulated by using multi body dynamics analysis software. The muscular systems based on Hill's characteristic equation that generate the knee extension and flexion with muscular contraction with considering active state of muscle. Lastly, the validity of the model and the way of approach are discussed.

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Despite of the fact that most artificial knee joints are made in order to imitate the human knee joint, a decreased range of motion due to contracture of the soft tissues and functional deficiencies were reported in postoperative outcome of total knee arthroplasty. Unfortunately, the knee joint after total arthroplasty cannot reproduce completely the kinematics and functions of the physiological knee joint. In this study, a new prosthetic geometry model of the femoral component for achieving deep flexion was developed based on the displacement and rotation as a function of muscle force and soft tissue restraints. The validity of this model was determined by comparing the results with those of the existing design shapes of total knee prostheses. A method for generating the optimal femoral prosthetic shape has been proposed. The optimal shape of the femur exhibited the reduction in the main active muscle force and the strain of the peripheral tissues during knee flexion. The proposed model improved the flexion and extension motion efficiencies of the total knee joint.

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For describing free-formed surfaces mathematically, parameterized polynomial function was proposed in our previous study. By using our parameterized polynomial, the artificial knee joint surfaces were described in detail and the results were found to be superior to the established practices. However, this polynomial function has some problem for reconstructing human knee joint surface with minute undulation. In the present study, to overcome this problem, an additional application of Fourier series approximation was employed. First, the global shape of objective surface was described by our polynomial function. Then, minute undulation was approximated with Fourier series function. Finally, two sets of approximated surface were superimposed to reproduce the original surface in a complete fashion. Our newly proposed method was applied to the swine knee joint and human knee joint model surfaces. Curvature analysis was performed for two surfaces.

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This paper deals with the measurement of 3D motion from 2D perspective projections of knee proshesis. Our previous study of computer model simulation has demonstrated that the technique archived sufficient accuracies of position/orientation estimation for knee prosthesis. Then we applied our algorithm to the CCD images, thereby examining the effects of various artifacts possibly incorporated through a photographing process on the estimation accuracies. A pilot study was performed such that the femoral/tibial component was set on a six-degree motion positioner, its single projection image was taken, and position/orientation estimation was carried out. We found that estimation accuracies in the experiment were deteriorated mainly by the geometric discrepancies between the actual and computer models and by the special inconsistencies between the coordinate axes of positioner and that of computer model. Yet, we verified that our algorithm could achieve proper and consistent estimation even for the CCD images. Thus we believe our technique would be applied to a clinical usage successfully by solving the above-mentioned problems.

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As the harvesting operation is hard work for farmers, it is desired to reduce the harvesting operation in agriculture. The purpose of this study is the construction of a useful visual recognition system that is required for automation and robotization of harvesting operations. In this research, eggplants and tomatoes are taken up as examples of agricultural objects. First, they are searched in a scene image using a genetic algorithm. Second, a recognition method for agricultural objects using Neural-Networks is proposed. In these Neural-Networks, the change of luminance information has been learned as special feature of agricultural objects, which show the luminosity distribution of objects composed of curved surfaces. Finally, through experimental studies, it is verified that the new technology proposed here is effective in the recognition of agricultural objects.

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In the obstacle avoidance of a legged type robot, it is not necessary to avoid all of obstacles by only turning, because it can get over or stride some of them, depending on the obstacle configuration and the state of the robot, unlike a wheel type or a crawler type robot. It is thought that the mobility efficiency to the destination is improved by getting-over or striding. In this paper, a neural network (NN) is used to determine the action of a quadruped robot in the obstacle avoidance path by using information on the destination, the obstacle configuration, and the robot's self-state. The design parameters of NN are adjusted by genetic algorithm (GA) offline. The effectiveness of the present method is proved through an actual experiment.

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This paper describes a teleoperation and communication support system with which to realize a new type of communication between two locations. Our system uses our developed Communication Terminal (CTerm). The CTerm is located at a local site and has a camera and a laser pointer that can be operated from an operation center. A skilled operator in an operation center makes his/her intentions to an unskilled worker in a remote site clear and concrete by directing the laser pointer to a particular spot, and this makes detailed oral descriptions unnecessary. There are two modes for controlling a direction of the laser pointer. In fast networks, the laser pointer is operated manually by remote control with a joystick. In slow networks, the laser pointer is controlled automatically by our proposed method based on the visual servoing. Our system allows easy communication between two locations without misunderstandings.

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In this paper, we propose a decentralized control algorithm of multiple mobile manipulators for handling a single object in cooperation with a human. In this algorithm, a grasping point of each mobile manipulator is controlled as if it has a caster-like dynamics referred to as virtual 3-D caster, and each mobile manipulator could handle the object based on an intentional force/moment applied by a human. In addition, the coordination among multiple mobile manipulators was realized without using the geometric relations among robots. The proposed control algorithm is experimentally applied to two mobile manipulators and experimental results illustrate the validity of the proposed control algorithm.

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A wire suspended manipulator in a three dimensional space on a vertical plane is developed. The system consists of a 4 D. O. F. manipulator and a crane with two wires. The base link of the manipulator is suspended by two wires those lengths and upper end positions are controlled respectively. In order to avoid the vibration and displacement of the suspended base link, not only the position and orientation of the end-effector but the position of the gravity center of the suspended part are controlled by using the 4 D. O. F. manipulator. Additionally, two wire directions are used for avoiding the positioning errors under the existence of external forces. Some fundamental experiments show the validity of the proposed control algorithm.

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When we make a controller for the nonlinear system, we usually solve the HJB/HJI equation. However, it is very difficult to solve them analytically/numerically. In this paper, "Differential Genetic Programming (DGP)" is proposed as a control design method. DGP has the properties to be able to make nonlinear functions automatically using Genetic Programming (GP), and also be able to differentiate the functions automatically. We demonstrated by numerical experiments that DGP is effective in HJI equation based design procedure.

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The purpose of this study is to control simultaneously, motion and vibration of a flexible flat-plate structure. For this purpose, we propose an extended physical modeling technique, which is able to expand to multi-body dynamics in flexible structures. And, the 2 DOF optimum integral control theory is applied to the control of motion and vibration of the structure. The result of simulation is compared with the result of the experiment. It is verified that this method is effective for high-speed motion and good vibratory control of plate structure.

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To evaluate performance of a developed engine, the vehicle model constructed on a computer can be virtually reproduced using a low-inertia dynamo. This engine test bed does not require any devices of the actual vehicle except for the engine. In this paper, we show a control method of a low-inertia dynamo connected to an engine with a six-speed gear transmission through a flywheel with a spring and a damper (FSD) and a steel shaft, in order to generate arbitrary load torque according to the vehicle model simulation. We regard the variation of the gear ratio with shifting of gears as the parameter variation in the system and apply μ-synthesis to obtain a single fixed-controller that is applicable from the first gear to the sixth gear. By carrying out simulations and experiments it is demonstrated that the μ controller designed is effective for virtual drive on the engine test bed.

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This paper proposes a novel robust fuzzy-neural network based control for the mechatoronic positioning servo systems that have nonlinear characteristics such as friction, backlash, variations of load and system parameters, and unknown disturbances. The proposed fuzzy-neural network based control scheme consists of three elements : a) a feedback compensation of velocity and position : b) a feedforward compensation which has inverse dynamics of the PD controlled plant based on neural networks ; and c) a nonlinear deviation compensator based on fuzzy neural networks. Computational and experimental results for one degree-of-freedom positioning system are shown to confirm the validity of the proposed controller.

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It's difficult to clarify deformation patterns in chaotic vibration of a beam, because multiple modes are generated simultaneously. This paper describes identification of spatial modes in a chaotic vibration for a buckled beam. KL (Karhunen-Loeve) method was applied to the identification. Using this method, time histories are decomposed into components which have no correlation each other. Contribution of the components to the original time histories can be estimated as eigenvalues of covarriance matrix of the time histories. Moreover, we used the corresponding eigenvectors to identify spatial modes in the chaos. We focused on chaotic motion of the beam involving a dynamic snap-through phenomena. The time histories for the identification were given from numerical analysis. The identified eigenvectors were compared with the natural modes of vibration. As a result, effectiveness of KL method was revealed.

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This paper deals with the case that an algorithm of continuous-time sliding mode control in which feedback gain coefficients are switched is digitally implemented in a digital computer. Since these coefficients are changed only at sampling instants, the system trajectory cannot be perfectly confined on a sliding hyperplane. As a results, the performance deterioration occurs. In this paper, the range is shown in which the switching control input guarantees to drive the state trajectory toward the sliding hyperplane and the swtching control algorithm is modified to be effective in it. A control algorithm is also proposed to keep the system trajectory in the narrowest neighborhood of the sliding hyperplane after the trajectory moving outside the range. The same discussion is further done for output tracking systems using sliding mode control. Finally, a numerical example is given for demonstrating the validity of the theoretical results.

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In the present study, a new technique for parameter identification of nonlinear vibration system is demonstrated using Wavelet transform. The Wavelet transform is a technique which provides the time-frequency representation of analyzed signal. The transform can be expressed as an inner product of the signal under analysis with a family of translations and dilations of one basic primitive known as the mother wavelet. Unlike Fourier analysis which yields an average amplitude and phase for each harmmonic in a data set, the wavelet transform produces an instantaneous estimate or local value for the amplitude and phase. This allows detailed study of non-stationary time-dependent signal characteristics. The identification method is illustrated using single-degree of freedom nonlinear vibration system with gap support characterized by piecewise linear spring property which exhibits nonlinear restoring force and also by coexisting viscous damping and friction during contact. It is shown numerically as well as experimentally that the proposed method well identified the parameter of the present nonlinear system. It is also known that the asymmetricity of the gap can be detected from the signal plane of time history of free vibration which is transformed by the Wavelet.

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Extracting symptom of bearing faults from noisy signal is a key problem to detect early faults of machinery. An effective method is presented for improving the signal to noise ratio by the wavelet transforms. The paper, which is Part I of a pair, describes wavelet de-noising algorithms and their properties. The relationship between the thresholds for wavelet coefficients and the ability of wavelet de-noise under Gaussian noise is discussed. The advantage of the wavelet de-noising procedure on simulated data is illustrated. Simulated results have shown that using wavelet de-noising procedure is an effective means to extract the signal from noisy data.

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Extracting symptom of bearing faults from noisy signal is a key problem to detect early faults of machinery. An effective method is presented for improving the signal to noise ratio by the wavelet transforms. The paper, which is Part II of a pair, illustrates the advantage of the wavelet de-noising procedure on a range of practical examples. We have made a comparison of failure detection-ability between envelope estimator and wavelet-based estimator under the noise condition of machinery. Experiment results have shown that using wavelet de-noising procedure is an effective means to extract early symptoms of machine fault form the heavy noise condition of machinery.

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Authors presented the newly derived governing equations of self-acting valve dynamics and the influence of valve characteristics on the valve behavior⁽⁶⁾. This paper describes the validity of the calculation method by comparing with experimental and field data. The calculated results agree well with the experimental results for the movements and impact speed of valves. Design values are obtained through comparison between the calculations of impact speed and the field data of valve damage.

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Two degree of freedom system represented by an equivalent mass-spring-damper describing chatter in sheet rolling is investigated. The dynamic behavior of the roll and excitation test indicated that chatter phenomenon is encountered in tandem cold mill wherein the roll stack vibrate in both vertical and horizontal directions. This paper assumes a friction model of the arc contact in roll bite which depends on the horizontal vibration of roll, and explains the vertical vibration in chatter is coupled with the horizontal one and therefore, both vibrations have influence on the dynamic behavior of the rolling force. The results of these analysis show the unstable area in the coefficient of friction producing a self-excited vibration and chatter phenomenon is caused by both excessive lubrication and inadequate one in the roll bites.

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We have developed a technique for estimating vibrations of vehicle body structures with damping materials using large-scale finite element (FE) model, which will enable us to grasp and to reduce high-frequency road noise (200∼500Hz). In the new technique, first order solutions for modal loss factors are derived applying asymptotic method. This method saves calculation time to estimate modal damping as a practical tool in the design stages of the body structures. Frequency responses were calculated using this technique and the results almost agreed with the test results. This technique can show the effect of damping materials on automotive body panels, and it enables the more efficient layout of the damping materials. Further, we clarified damping properties of car structures under coupled vibration between frames and panels with viscoelastic layers.

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It is known that flutter of a traveling sheet may occur during its manufacturing process under the influence of leakage flow between the traveling sheet and a guide. In order to avoid the quality defectiveness like wrinkle due to the unsteady phenomenon happening on the sheet, a nonlinear stability analysis of sheet subjected to a leakage flow are performed to study the behavior of sheet in this paper. Concretely, sheet is described as a model consisting of mass less beam elements, springs and discrete mass particles, in which the mass of each particle and spring coefficients are calculated based on the beam model. During the formulation of fluid dynamic forces, nonlinear terms are taken into account for simulation of large-amplitude vibration of sheet, showing the appearance of limit cycle vibration in high flow velocity.

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Vibration mode of a truss structure is different to that of a cantilever. The objective of the present work is to establish a new sensing technique for specific vibration mode of the truss. In this method the distributed modal sensor is employed to determine the vibration mode. First the design process for a modal filtering method is examined using a one-dimensionally distributed modal sensor. Then the shape of the vibration mode, which is required for designing the sensor, is determined and, based on the displacement distribution of this mode shape, a modal filter can be designed. If the sensor is designed under the condition of a fixed vibration mode, the error signals introduced during the measurement are considered to cause unfavorable effect on the sensitivity. As a counter measure, a polynomial approximation with minimum errors is used to smooth the measured vibration mode. The modal filter designed above is attached to the truss structure and excitation tests of the truss are conducted for evaluating separation performance of the modal filter. By comparing the results of the present system with a distributed modal sensor and the inertial mass actuator system commonly used so far, it is found that the present sensing method is far more useful.

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Noise reduction and vibration control at high speed railway are required to improve the interior noise characteristics of aluminium car body system, which is used shinkansen train and express train. However, it becomes difficult to maintain the vibration control of one link mechanism between the car body and the car bogie. In this paper, to improve the damping performances of one link mechanism, we have proposed the new type noise reduction link mechanism using granular materials. Factors which affect on damping performances are examined through experimental study. New type noise reduction link mechanism is considered via examining damping performance with granular mass effect and friction effect. Finally, in the experiment of vibration bench test, new type noise reduction link mechanism is improved by max. 11dB in comparison with the conventional one.

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In the present paper, we study on a control design using parallel compensation technique. Parallel compensation technique is applied to many control design problem such as simple adaptive control, robust control using phase information and the parametrization of all proper stabilizing controllers for minimum phase strictly proper system. The parallel compensation technique is used so as to expand applicable plant of simple adaptive control and robust control using phase information. However the relationship between controllers that is obtained using parallel compensation technique and the parametrization of all stabilizing controllers have never considered. In the present paper, we consider this problem and give the necessary and sufficient condition that the class of controllers that is obtained using parallel compensation technique equal to that of controllers for the plant.

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Four-Track Steering Vehicles (4TS) equipped with triangular track, or crawler units in place of regular tires have been developed for off-road use. Since the crawler units swing about the axles of the drive sprockets and make large contact areas with irregular ground, 4TS is expected to improve its performance on rough and soft ground. In this research, a numerical 4TS model in the pitch-plane was constructed by using Lagrange's equations of motion. Track unit motion was considered in the numerical model to simulate the vehicle motion on several non-level ground configurations. In order to examine the numerical model, scale model experiments were also conducted. The validity of the numerical model was observed.

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A method is proposed to analyze dynamic response of a rocket-launcher system at lift-off. In this paper, rocket-launcher system is modeled as finite element Bernoulli-Euler beams connected with two slippers which are modeled as linear springs. A beam element with a moving spring is devised to represent the rocket-launcher interaction. Coupled equations of motion with time-varying coefficients are derived and solved by using direct method such as the Wilson θ method to calculate the dynamic response of the system. To verify the validity of this method, dynamic response is calculated by using the data of M-3S rocket-launcher system. Two rocket models, rigid-body and elastic-body models, are used in this calculation. The numerical results obtained from two models are compared and discussed.

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In this paper, an output optimization control of variable pitch wind turbines is discussed. Based on adaptive exptemum control scheme proposed by Krstic et al., such a pitch control system that maximizes output of wind turbines below rated wind speed, and regulates output of wind turbines above rated wind speed is proposed for variable pitch wind turbines. In order to apply the designed control system to practical wind turbines, first, a two-blades micro wind turbine with variable pitch structure was manufactured and modeling was performed through the wind tunnel experiment. Second, computer simulator was created based on the determined mathematical model of the wind turbine, besides the control system was applied to the simulator and effectiveness of the proposed control system is verified through the simulation works. Finally, to evaluate the practical use of the control system, experimental works were carried out for the manufactured wind turbine.

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For a steel pipe with upset, heat treatment will be required to improve mechanical properties such as high tensile strength, fracture toughness and so on. When a pipe with upset is heated by induction heating, predetermined target preheating temperature distribution is very effective to get uniform heat treatment temperature. However, it is not so easy to get the target temperature distribution. Since induction heating has electro-magnetic edge effect at pipe end and selection of preheating position is difficult due to many discrete positions. To get the target temperature distribution, optimal control procedures using finite element method, regression analysis and non-linear programming are presented. It is found that the procedures are effective to achieve the target temperature distribution. Since estimate by FEM using preheating conditions obtained by the procedures can almost agree with the target preheating temperature distribution.

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Polychlorinated biphenyls (PCBs) are environmental chemicals and there are few methods for real-time PCB measurement. This study demonstrates the applicability of the real-time measurement of PCBs using LI-TOFMS (Laser Ionization Time of Flight Mass Spectroscopy). In order to develop a highly selective and sensitive method, the effective laser wavelength and pulse width for laser ionization of PCBs are discussed. Excitation at λ=266nm is found to be substantially more effective than at λ=280, 300 or 320nm. Also picosecond excitation for PCBs undergoes more efficient ionization (by a factor of over 10) and less fragmentation than nanosecond excitation. The achievable trichlorinated biphenyl sensitivity for real-time (1min) measurement using the LI-TOFMS technique is determined to be in the sub-ppbV range (<0.01mg/Nm³).

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Nowadays, some typical robots which communicate with patients or aged persons have been developed. They are used no longer serve the ordinary works but also recover good temper of users. For the children of kindergarten, exchanging greeting every morning is important chance to allay their uneasiness and become emotional action. Then we develop the robots which relief and exchange greeting for teachers of kindergarten. Because the shapes and faculties of robots affect the good temper, in this paper we produce some robots by way of trial and produced feeling test by the children of kindergarten. Through this test, we can grasp the most suitable shapes and faculties of robots which can communicate with children with a sense of incongruity. The data will be used when we construct an actual robots which exchange greetings with children.

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Small and light drive train is strongly demanded for vehicles and for e. g. aerospace crafts to accomplish comfortable transportation and large space for passengers. Gears used for those drive trains must therefore be small but excellent in load carrying capacity. At designing those gears, simulation of gear performance is one of the best methods to be taken today, because multiple failure modes must be considered simultaneously. It is however difficult to analyze all of possible combinations of dimensions and tooth flank forms of gears, because of large number of parameters. Today, those parameters are usually decided by trial and error by experienced designers. In this report, the characteristics of gear dimensions to satisfy the requirements against tooth breakage, pitting and scuffing of tooth flank are investigated under geometrical and other limitations of gears, where center distance, gear ratio and face width are fixed. The optimum combination exists in pressure angle and tooth depth, if optimum addendum modification factor and helix angle are given. Optimizing decision method of pressure angle, helix angle, addendum modification factor and tooth depth for high load carrying capacity is proposed.

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Motor power of vehicles is increasing to accomplish more speedy and comfortable drive. On the other hand, smaller and lighter drive train is required to expand the internal space of vehicles. Gears used for those drive trains must therefore have high load carrying capacity. In this report, gearbox whose center distance, gear ratio and face width are fixed, is treated and the influence of module, number of teeth and profile modification of tooth flank on load carrying capacity is investigated, where pressure angle, helix angle, addendum modification factor and tooth depth are optimized by the method proposed in the previous report. There is an optimum value of module in load carrying capacity and the characteristic of the optimum module depends on tooth number. Tooth profile modification for larger module gear contributes to improve load carrying capacity, but that has small effects for small module gears. Asymmetrical tooth profile form correction has little advantage if gear dimensions are optimized. Total decision method of gear specification for high load carrying capacity is proposed, which includes the decision of module, number of teeth, pressure angle, helix angle, addendum modification factor and tooth depth and profile modification of tooth flank as well. Endurance test of the gears designed by the proposed method is carried out and the improvement in gear life is confirmed.

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The air film thickness between a foil and a drum is studied experimentally using a measuring system under conditions where the Air film thickness is effected by the bending stiffness of the foil. For comparatively flexible foil cases, the experimental results coincide fairly well with theoretical ones obtained by applying the separation boundary condition. For cases with stiffer foil conditions, the tendency of the experimental results may also be explained well by the theoretical analysis, by introducing the concept of the tangency point condition as well as the infinity point condition for the film pressure generation point The theoretical tool of Finite Element Method is used to analyze film thickness and pressure distribution in a foil bearing for various values of foil stiffness, The calculated results agree with the experimental data, and it is concluded that the shallow shells model is useful and accurate.

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An ultrasonic technique is applied for detection of abnormalities in a ball bearing in its life test. Ultrasonic wave pulses are entered into a bearing housing from a piezoelectric vibrator attached to the outside of the housing. Those pulses are partially reflected from the interface between the housing and the outer ring of the bearing. Because of the different acoustic impedance between the solid-to-solid contact and the contact with an intervening gas or liquid layer, the intensity of the echo depends on the real contact area formed at the interface, and it can be used as a measure of the local contact pressure. When determined in the loading zone of the bearing which is running in a normal condition, the intensity of the filtered echo pulses produces smooth, nearly sinusoidal peaks corre- sponding to passages of the balls. However, invasion of a solid particle like wear debris to the rolling surface between a ball and either of the raceways causes a sudden rise of the local contact pressure, while a flaw formed on their rolling surface causes its sudden drop. The experimental results show these "events" are detected by the ultrasonic technique, and, further, a simple sum of the intensity or of the time duration of those events over a certain period starts to increase when the cumulative number of revolution reaches, typically, 80% of the total bearing life. This indicates the possibility of the early detection of abnormalities in ball bearings which lead to fatigue failure due to surface-originated cracks.

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The strategic importance of new product development is steadily increasing and machine tools manufacturers require effective new product development methodology to achieve sustainable competitive advantages. New product development strategy is an essential element of the overall corporate strategy and especially the decision of selecting optimal resource has significant effects on customers' satisfaction and product quality. However, most of the current available methodologies remain limited performance. In this study, the key capabilities of some machine tools manufacture have been summarized based on the results of the interview investigations with top managements in Japanese machine tools manufactures. Furthermore, a structured method for identifying and evaluating the core competence in machine tools manufacturers can be proposed using pairwise comparison matrices. By using the proposed method, the core competence in an objective machine tools manufacturer can be evaluated from both qualitative and quantitative evaluations.

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This paper describes a new suggestin of a method for analyzing expert's skills relating to the decisionmaking process in cutting conditions set-up. An ANP model with outer dependence is employed to estimate their skills quantitatively by analyzing their subjective or feelings. The decision-making process is described as a hierarchical structure with two layers, which are criteria parts and cutting condition parameter ones. Then the ANP analysis is carried out to obtain weighting matrixes from criteria to cutting conditions and the reverses are evaluated, respectively after an interview to experts. They are embedded in a super-matrix for analyzing detail decision-making processes. An example on the cutting conditions setup of an expert in drilling is displayed, in which it is cleared what he thinks on the process and his ideas on the process can be reflected well.

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Ball end mills are useful cutters for machining three dimensional shapes, such as a molds or dies. While, recently it possible to machine hardened steel at high cutting speeds using a machine of which the spindle speed is over tens of thousand of revolutions per minute and a coated solid carbide tool which is developed for hardened steel machining. In such high speed machining of hardened steel, small size ball end mills are frequently used. But, the relationship between the shape of the machined surface and the tool deformation by cutting force is not cleared. Then, the aim of this study is to make clear the surface generating mechanism of ball end mill based of deflection by FEM. The main results are as followings. (1) FEM model of a small size ball end mill is shown and the variation of the cutting area by the cutting edge of ball part is calculated using 3D-CAD. (2) The rotational angle of the cutting edge which generates each resultant cutting force during cutting tests is obtained by comparing the variation of the cutting area with that of the resultant cutting force. (3) The deflection of the ball end mill is calculated by FEM and the shape of the machined surface is predicted by summation of cutting edge positions which are obtained by the cutter deflection and the cutter rotation duming machining. (4) The predicted shape is almost coincident to the experimental shape, so the method of calculation for the machined shape by a small size ball end mill is verified.

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In this paper, the flank wear and the surface roughness of a machined surface are investigated by high speed milling of hardened steel on a small size ball end mill using a high speed spindle attachment. And also an investigation is carried out on the influence of a tool life on the minimum quality lubrication (MQL) method. The main results are as follows. (1) The flank wear of the cutting edge increases in proportion to the cutting length, and the flank wear shape gradually brings the shape of the actual cutting length close. (2) It is shown that the long tool life is obtained by the conditions of the step down pick feed and the down milling with MQL method to the end point of each milling process. (3) The surface roughness increases in proportion to the cutting length. But using the same cooling method described in (2), the small surface roughness of 3 μm is obtained till 2000m of cutting length. (4) Under the cutting conditions, bidirectional milling is an effective milling method by reason of the shortest cutting time that is about 70% of other types of milling and the longer tool life that is about 90% of the maximum tool life obtained by down milling.

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The dimensional accuracy of built-in parallel rollers is generally considered a significant factor affecting the movement accuracy of high-precision machining tools. A previous report based on the V-block method examines dimensional distortion of 1200 parallel rollers to obtain it's effect on movement accuracy of machining tools equipped with these rollers. Yet, these results are based on roundness measurements of a single cross-section, and thus lack preciseness in illustrating the complete dimensional profile of the rollers. Thus in this report, we introduce a newly developed method enabling mearurement of simplified cylindricity. The roller was supported at two points by two independent V-blocks, while measurements were simultaneously taken at three points ; namely the two cross-sections supported by the V-blocks and a third cross-section. These results were combined to provide the cylindricity of the measured roller. Furthermore, 200 parallel rollers of a uniform standard were measured to analyze the distribution of radius, roundness, and cylindricity.

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An O-shaped constant-torque spring is made of pre-stressed material and offers the advantage of constant torque and is being made in various sizes, suitable for a variety of applications (for example, drive mechanism, counterbalance, retracting and restoring mechanism). This spring takes the form of a tightly wound spiral and is placed on two drums. When the device is wound up by winding the spiral from the first drum to the second drum, the constant torque is developed. In this report, the mechanism of constant torque and states of deformation are analyzed by using a large deformation theory. Moreover, an experiment is carried out to confirm the applicability of the proposed theory. The experimental results agree well with the theoretical estimations.

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