We describe a new method for solving large-scale system of linear equations resulting from discretization of ordinary differential equation and partial differential equation directly. This new method effectively reduces the memory capacity requirements and computing time problems for analyses using finite difference method and finite element method. In this paper we have tried to solve one-million linear equations directly for the case that initial displacement and boundary displacement are known about the finite difference scheme of second order inhomogeneous differential equation for vibration of a 10-story structure. Excellent results were got.

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In order to suppress vibrations of stay cables in cable-stayed bridges, the authors developed a new vibration reduction method called "Changing vibration modes method" using a permanent magnet. The authors have confirmed its effectiveness in former reports by both theoretical analyses and wind tunnel tests. In second report, the authors analyzed cable vibrations by taking account of only an unstable mode and clarified how the design parameters such as a gap and magnetic force affect the control efficiency. In this report, accuracy of the analysis is further improved by introducing the higher modes effects as an "equivalent aerodynamic damping". Then, a design procedure of the parameters is proposed on the basis of the improved analysis, and its validity is shown by wind tunnel test results.

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In order to suppress vibrations of stay cables in cable-stayed bridges, the authors developed a new vibration reduction method called "Changing vibration modes method" using a permanent magnet. With this method, growth of the unstable fundamental vibration mode is prevented by dissipating energy of higher stable modes. The authors have confirmed in former reports that the proposed method effectively reduces the self-induced cable vibrations by both theoretical analyses and wind tunnel tests and design method of the device was proposed. In this report, first, the design process of a prototype of a control device is described. Second, higher mode vibrations generated by the action of the device were confirmed from the results of free vibration tests. Finally, efficiency of the proposed countermeasure against rain-wind-induced vibrations of an actual cable is clarified.

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Servo control is one of the most important control techniques for motion control of mechanical structures. Generally, the servo control consists of reference trajectories and a feedback controller. Many recent studies in the control engineering field have treated recent design methods of feedback controllers taking account of several control specifications. However, generally, the ability of an actual feedback controller is strictly limited due to its cost or difficulties of realization. Different from the above approaches, this study proposes a novel framework for the motion control of mechanical structures. It means a combination of a high performance reference generation and a simple feedback controller. References are generated by an offline simulator taking several specifications into account. As an example, we discuss a positioning control of a vibration system and utilize a nonstationary optimal control simulator and a sliding mode feedback controller. The effectiveness of the method is verified by numerical calculations and experiments.

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This paper describes the random vibration of a cylindrical structure in a pipe located just downstream of a valve. The cylindrical structure is a cantilevered circular pipe and the root stress, the acceleration of the pipe and the fluctuating velocity are measured with the flow velocity. As a result, it was found that the choice resonance occurred from the fact that only the natural frequency components of the vibration were dominant, the vibration due to the vortex shedding could not be observed in a strong turbulence flow and the second mode vibration is too small comparing with the first mode vibration to become the cause of failure. Moreover the fluctuating velocity could be normalized by the turbulent scale length, the velocity and the mean square of turbulence.

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The periodic pressure fluctuation with a very long period of around 5 minutes is observed in pressure measurements by a Pitot tube in a high speed rotating cylinder. The observed frequency is much lower than the rotational speed or calculated Karman vortex frequency. Theoretical analysis is also done in considering the fluid forces that act on a Pitot tube. Theoretical results show good agreement with the experimental ones. Consequently, the observed vibration is induced by hydrodynamic force which whirls the Pitot tube.

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In rotating machinery, there are not a few cases of failure of structure such as unbalance, misalignment and looseness. The failure of structure causes the secondary failures by giving too much stress to bearings. The conventional diagnostic method has measured the vibration amplitude and compared them with the alarm level. As the alarm level depends on the machine size, rotating speed and other operating conditions, we must prepare for the alarm level for each machine. The diagnostic method without using the alarm level has been expected. In this paper we propose a diagnostic algorithm using new deteriorative parameters which are obtained by both amplitude domain and frequency domain. We specified total power spectra caused by the fault as the deteriorative parameter in frequency domain, and we also specified logarithm of the RMS value of vibration velocity as the deteriorative parameter in amplitude domain. We examined this diagnostic algorithm by applying to the actual measured vibration data. Finally we described a handheld type machinery fault checker that is equipped with the diagnostic algorithm.

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An optimal method is developed to estimate the dynamic loads for systems subjected to multiple inputs. The method focuses on minimizing the ensemble mean square error of the estimation. First, the inverse system analysis technique is employed to establish the error estimation equation. Then, by applying the noncausal Wiener filtering theory, the optimal estimator of dynamic loads is derived out. Both numerical simulation and experimental results demonstrate that the method is of a good ability in suppressing the influence of measurement noises than conventional methods, which based on solving inverse matrix of transfer function, and is rather effective and practicable for dynamic load estimation.

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This paper proposes a positioning system for indoor vehicles, which uses an odometry, ultrasonic sensors and an environment map. The system cancels the accumulating error in odometry using the range data to the wall or edge landmarks measured by ultrasonic sensor. This method requires only a simple hardware, however, it is necessary to find the correspondence between the real sensor datum and a landmark in the environment map. At first this paper describes the outline of the previous works on indoor positioning systems, and then proposes a new structure of a practical positioning system. This structure uses an ultrasonic sensor simulator to solve this correspondence problem. Finally this paper shows our experimental system on our mobile robot, and results, which show the effectiveness of this method.

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The scroll compressor having an asymmetric scroll wrap has been developed as a kind of means to attain the high efficiency, low noise, and compact size as compared to that with a symmetric scroll wrap in recent years. However, an asymmetric scroll compressor causes the large imbalance gas forces due to the pressure difference in a pair of compression chambers. The forces influence dynamic behavior of the orbiting scroll and the Oldham ring, and they will lead to the unfavorable noise and vibration during the operation. In this paper, we have identified such problems of an asymmetric scroll by measuring the motion of Oldham ring and the acceleration of the casing under the various operating conditions. We have compared the experimental results with those of a symmetric scroll. In addition, we have suggested the effectiveness of a reed valve as a discharge valve to reduce the impulse noise and the rotational displacement of Oldham ring, and have tried to optimize the shape of reed valve with the help of the experimental planning method using the orthogonal array.

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A method for calculating the pulsation response of reciprocating compressor piping systems using convolution integral is proposed. The method considers the interaction between the valve motion of compressors and the pulsation of piping systems. Compressors are simulated by integrating the deferential equations, and pulsations in piping systems are simultaneously calculated by convolution integrals. Impulse responses of piping systems are evaluated as Fourier transforms of the impedances that are calculated by admittance matrix method including attenuations by mean flow. By this approach, Complex piping systems connected to multiple compressors are easily analyzed. Experiments were carried out with a model piping system that had a reciprocating compressor and a vibrating piston. Impedances of the piping system with mean flows were measured using an accelerometer on the vibrating piston and pressure sensors at the pipes. Predicted impedances and simulated pressures for the piping system were compared with the experimental results and good agreement was obtained.

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The authors have already developed a numerical approach for estimating a ski turn caused by a skier's ski control (edging action). By using the approach one can discuss the effects of the shape and mechanical properties of ski, the physical strength and ski control of skier, and the snow slope on the ski turn. In the present study, the effects of the ski model on the ski turn are discussed. First, the shape and mechanical properties of slalom model, carving model, free ride model and moguls model are measured. Next, the effects of the kind of ski, skier's ski control and hardness of the snow slope on the ski turn are discussed. Finally, a new evaluating method is proposed for the evaluation of the ski turn. Two evaluating indexes, "the locus of ski turn" and "the rotation of ski", are used in the method. From the numerical discussions it follows that one can make clear the character of each ski model at the ski turn by using the evaluating method.

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Low frequency noise radiated from an enclosure can pose an environmental problem. The power attenuation of sound absorption materials or barriers is relatively poor at low frequencies. Therefore, the authors propose a method employing an active noise control in order to minimize the total acoustic power in an enclosure by reducing sound pressure, leading to the noise reduction in the entire area around an enclosure. Suitable arrangement of sources and sound pressure reduction point is investigated on the basis of theoretical estimation. The power attenuation effect of an enclosure was confirmed and compared with those of other methods.

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In the rollermill used in the industrial field, the worker does not stop the roll and often carries out supplies of sheets and cleaning of the roll. Safety measures by fence or enclosure were difficult for such works, as the worker approaches the rollermill very closely. A new safety system with the floating function was developed in this study to solve these problems. It permits the running of the roll only when the blinded light beam number is less than the set number, and the roll stops when the condition except for it. The safe work became possible not only in automatic operation but also supplies of sheets and cleaning of the roll. It also realized the fail-safe floating control equipment, fail-safe rotational speed monitor and fail-safe safety distance monitor by the diversity controller with the self-checking function. Experimental results are described as follows ; 1) The smallest detection diameter M was expressed by M=bF+φ_M, where F is the floating light beam number, b is the interval of the optic axis and φ_M is the physical resolution of the photo-electric sensor. 2) The detection of the human body was possible when the sheet was bent or the human body was hidden in the blind area of hand tool.

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In the present paper, we examine a design method for master-slave systems of bilateral control systems. In master-slave systems, human operator works to achieve tasks via the master and the slave system. The slave system contacts the environment and works the tasks. According to past studies, when the dynamics of environment is treated as uncertainties, the number of unstable poles of the slave system is required to be equivalent to that of the slave system with the dynamics of the environment. In some cases, the number of unstable poles of the slave system with the dynamics of environment is different from that of the slave system. We propose a simple design method of bilateral control systems such that the number of unstable poles of the slave system with the dynamics of environment is different from that of the slave system without the dynamics of the environment.

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High speed superplasticity has firstly realized at room temperature with Zn-Al alloy nano-sized. The Zn-Al alloy has some fine property in comparison with the low yield point steel, which has low hardening and large ductility. And it doesn't contained Pb. But, when the Zn-Al alloy deformed, local deformation is occurred by it's low hardening, and the deformed part is broken locally. In this paper, It is presented to design the seismic damper made of the Zn-Al alloy without the local deformation. Therefore, ecological and high performance seismic damper has been successful to developing, so-called "maintenance-free seismic device".

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This paper investigates the characteristics of recognizing emotions contained in human speech. The concept of artificial neural networks (ANNs) is adopted for a recognition algorithm. An approach based on the Hidden Markov model (HMM) is also investigated as an alternative recognition method. Using a large database of phoneme-balanced Japanese words, both recognition systems are trained and tested. To evaluate the emotion recognition results obtained by using ANNs or HMMs, emotion recognition testing is carried out with human subjects. The obtained average emotion recognition rates are 51% using ANNs, 32% using HMMs, and 55% with humans. Experimental results confirm that the emotion recognition rate achieved by using the ANNs in the speaker and context-independent mode is feasible and that ANNs are well suited to this task.

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In order to estimate the motion of floor image, a visual device has been developed that can track images from a monocrome CCD camera directed to flat floor. This device provides positional information for mobile robots to be navigated. We describe a new structure and updating method of template image in correlation processing to track floor images which have a natural texture. Based on this method, electronic circuits in a CPLD has been manufactured which process the image tracking at video rate. The results of experiments on the floor at indoor room and on the outdoor road show that this device can measure the 2-D motion of floor image from camera. The size of this device is so compact that it can be mounted to small mobile robots as the positioning sensor.

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Engineering Test Satellite-VII (ETS-VII) is the test satellite to demonstrate and verify rendezvous docking technology. After success in an autonomous rendezvous docking in the 1st and 2nd experiment flights in 1998, we performed remote pilot rendezvous experiment by ETS-VII in Oct. 1999. In the experiment, ETS-VII was controlled by a ground pilot via Tracking and Data Relay Satellite (TDRS). To overcome long time delay and poor information on thruster acceleration, the ground pilot predicted the changes of position and velocity after thruster firing, and controlled the Chaser satellite. In this paper, we present the result and evaluation of the remote pilot experiment. It could be shown that remote pilot was very useful to control rendezvous spacecraft with long time delay and/or with unknown control characteristics.

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The simple expressions of equations for force and dynamic analysis of parallel mechanisms can be obtained by expressing the twists and wrenches in a connecting chain by the coordinate vectors on the dual bases of its dual spaces, which are the motion space and the wrench space. The basis of the motion space of a connecting chain is composed of the joint axes in it and the basis of the wrench space is determined to be its dual basis. Expressing the wrenches acting on its links by coordinate vectors on the dual basis gives the closed form concise expressions for the analysis. The relations between active joint torques and wrenches acting on links can be expressed by only matrices composed of dual bases of the connecting chains, and torques of the joints of the tree type mechanism obtained by cutting loops of a parallel mechanism.

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This study investigates the positioning and the vibration isolation performance of a precise positioning mechanism which is composed of a electromagnetic actuator using a rubber film. The results obtained by the experiments are as follows : (1) The actuator has the hysteresis, but it has not influence on the positioning accuracy by applying PI control. (2) The rubber film plays the part of the passive vibration isolation. (3) As a result of employing the disturbance cancellation control, the vibration isolation performance improves further.

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This paper discusses an object capturing task with a two-arm flexible manipulator. To realize a stable capture with no slips at the end-effectors on the object surface, the internal force being developed in the object needs to rise quickly. For this purpose, the relationship between the end-effectors' approach velocities to the object and the internal force during the capture is analyzed with a simple mass-damper-spring model for the two-arm manipulator and the object system. Furthermore, a method for changing the control modes is proposed considering the resultant mechanical compliances at the tips of the arms so that the rise time of the internal force is reduced. The effectiveness of this method is verified with experiments.

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This paper presents a path following feedback control method for platoons of multiple car-like mobile robots. We first define a system whose four variables are the relative position and relative orientation of the robot to the path followed and the steering angle, and we secondly convert the system into a chained form system. One of the four variables of the chained form is the moving distance of the robot along the path. By making the robot move, the feedback control method makes the other three variables converge into zero, which is equivalent to making the robot follow the path. The robot especially can follow a smooth path. Connecting multiple paths and adjusting the moving velocities of the robots on the paths enable them to make a platoon. The validity of this feedback control method is supported by computer simulations.

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This paper presents the identification of inertia parameters, such as mass, moment of inertia and product of inertia, of a free-flying space robot. Making use of the law of momentum conservation, an identification algorithm which does not require torque or acceleration measurment is developed. Gravity gradient torques are also used to identify the product of inertia. The algorithm is verified with the flight data obtained by the ETS-VII, Japanese space robot.

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Power grasp or enveloping grasp enables multifingered robot hands to grasp an object firmly by constraining it with multiple contacts with the surfaces of the finger links and palm. Most of power grasps can maintain equilibrium against external force/moment in all directions with constant joint torques as long as their contacts are unbroken. This paper proves that this condition is equivalent to the condition that the grasp force in power grasps is statically indeterminate. We propose two algorithms for computing optimal joint torques for power grasps taking the indeterminacy into consideration. The first algorithm computes the most robust joint torques against changes in external force/moment. The second one computes the minimum magnitude of joint torques in order to maintain equilibrium against a given set of external force/moment. These algorithms are independent of computation of the indeterminate grasp force if it is linear for joint torques and external force/moment.

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As the applied voltage to the wheelset on a track circuit fluctuates according to the distance between the track circuit's sending end and the train's position, it is very difficult to investigate the shunting resistance by the running train's wheelset. The authors proposed an experimental model test track circuit to keep the applied voltage to the wheelset on the track circuit constant. On the proposed track circuit, the shunting current flowing in the axle was measured so as to investigate the shunting resistance of the running wheelset. As the results, the behavior of the shunting current in the running wheelset was made clear with the shunting resistance of the single running wheelset. However, when the twin wheelsets shunted the circuit, the fluctuation of the shunting current of the wheelset was too significant to determine the shunting resistance.

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We have developed an articulated-type small monorail car with good curving performance. This Small monorail car uses articulated trucks to reduce vehicle weight and is designed to negotiate a 40-m-radius sharp curve, enabling flexible track design in cities. A curving simulation algorithm for an articulated multi-car system has been developed by using inter-segment coordinate systems to connect separate segments, in which all displacements are sufficiently small to be linearly approximated. The curving dynamics of the car were evaluated using the proposed simulation algorithm. The simulation results showed that the yaw moment resistance between the car body and the truck can be reduced by using low-longitudinal-stiffness air springs. With the low-longitudinal-stiffness air springs we have improved the curving performance of the small type monorail car that can negotiate 40-m-radius sharp curve with small guide tire force and small slip angle of the running tires.

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ER fluid is a fluid whose rheological characteristics can be controlled by electric field. We firstly developed a brake device using particle-type ER fluid which has good controllability. Then, we developed an isokinetic exercise system using the ER brake. Isokinetic exercise is a training under the restriction of constant rotational speed of joint during the exercise. Such passive system using a brake is inherently safe for human. The developed system showed good properties for isokinetic exercise.

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"Arch moment" of human foot complex is determined by model analysis using Newton-Euler inverse dynamics argorism. Human foot is arch shaped structure that is highly complex, composed of 28 bones, any ligaments and intrinsic/extrinsic musculotendons support. The arch displacement occurs during a gait cycle. This motion has an instant center, which is placed on the navicular bone, as we have decided using X-ray analysis. The foot model is constructed by two rigid bodies connected with one hinge joint. The arch moment determination materials are (1) kinetic and kinematic data, (2) body segment parameters. Each floor reaction force to forefoot and hindfoot are measured by two force plates. Three adult subjects were studied during normal gait. The anthropometric data are acquired by 12-camera VICON system. The body segment parameters are estimation data using plaster model. We discuss that the arch moment is equal to the arch support moment composed of ligaments and muscles, and the ligaments constraint the foot arch like a rope.

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There is an increasing interest in the research and the development on micro machines and small gears as their components. It has also been an attempt to produce small gears as a technical challenge. A successful operation of those gears is doubtful in view of gear design, as there has been no consideration on their mechanical properties. It is essential to define the failure mode when discussing the gear strength but very little is known about gear teeth failure of small gears. Thus the strength of spur gear teeth with small modules of the order of 0. 1 to 1 .0 mm has been studied by using a specially designed gear test rig. Higher precisions in alignment is achieved which is appropriate for small gears. The failure mode of gear teeth was observed for both tempered and soft nitrided gears. A sign of uneven contact along face width was found only for very small gears of modules 0.1 and 0.2 mm, which is very unlikely for such high precision in alignments of gear axes. This resulted in the tooth breakage after extended period of operation. A characteristic failure at tooth tip, also on the tooth crest, was found.

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This research aims at developing a new lapping process which can make efficiently tooth flanks of hardened steel gears smooth as a mirror. The lapping process is carried out using a nylon helical gear and a simple mechanical device. This paper shows causes of increases of tooth profile errors in this lapping and proposes how to prevent them according to results of lapping tests with many ground high-precision gears under various conditions. It is concluded that it is important to carry out the lapping for a short time using a nylon gear which has a large helix angle and high-teeth under a condition of high-speed revolution and light load in order to prevent increases of tooth profile errors.

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Rippling failure occurring on rollers and gears is well known as one of the phenomena resulting from plastic flow of the surface layer caused by repeated sliding-rolling contact. We have alreadyreported some experimental results on the rippling failure. The rippling failure is closely related to lubricant. In this paper, we considered how lubricants influence the rippling failure. In particular, the effects of additives of lubricating oils were investigated in detail by roller test. The oils added several additives to automotive gear oils were used as lubricant. Consequently, the following becomes clear in this paper. The coefficient of friction is related to the occurrence of rippling, and the gear oil which has higher coefficient of friction is easier to generate the rippling. For the automotive S-P type gear oil, to add the borate (dipotassium tetraborate tetrahydrate) is effective to prevent the occurrence of rippling failure.

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For example, strain-hardened aluminum sheet has only poor stretchability. But it has still enough ductility. This study aims to give the same deformation as "stretching" for these materials not by tension in plane but compression for thickness direction. Tooth-shaped tool was made, and thin aluminum sheet was compressed between the tool and flat die. Material under the tooth yielded, flowed out into grooves next the tooth, buckled, and formed wrinkle. To check stretchability of sheet with wrinkle, strip specimen was machined out and examined. The strip did not fracture by tensile force before the wrinkle was stretched out. Finally sheet with wrinkle was pure-stretched using an elliptic-headed punch and confirmed to have very large forming depth.

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This paper presents a geometric analysis of an undeformed chip thickness at the top of tool in ball-nosed end milling. It has been firstly pointed out "backward cutting" near the center of tool that is irregular interference between the flank and the workpiece. So "backward cutting" occurs a non contact part on the cutting edge. Secondly a condition of "backward cutting" has been clarified. An area of "backward cutting" in a ball-nosed end mill is shaped circle that exists beside the center of tool axis. Thirdly a method of avoidance from "backward cutting" has been brought up. Then its influence for surface roughness is verified by a few experiments.

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New vibration assisted magnetic abrasive finishing process using pulsed pressure is proposed in order to develop highly efficient finishing technology. All previous studies have developed the magnetic abrasive machining under a constant pressure. This paper describes plane magnetic abrasive finishing process under a pulsed pressure that workpiece is vibrated in a vertical direction or elliptical direction to the machined surface. Some kinds of experiments have been carried out in order to investigate the machining effects resulted from pulsed pressure. The machining characteristics are represented summarily and the mechanism is discussed. The vertical vibration-assisted process leads to higher finishing efficiency and rougher surface than conventional process under a constant pressure. However, the elliptical vibration-assisted magnetic finishing process, results in a good finish and high removal rate.

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The purpose of this research is to develop a distributed simulation synchronization mechanism including a function for managing distributed simulation clocks without the rollback function. The mechanism is based on a storage model which is used a characteristics of storage function in manufacturing systems. In this paper, the storage model concept and an algorithm to implement the proposed concept are described. We develop a distributed simulation system configuration using HLA. A case study was then carried out to evaluate the performance of the cooperative work.

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In this manuscript three types of learning experience with different work contents and factors were carried out, and an evaluation standard setting method was established for the respective work learning by work achievement method. The professing equation in production where both working time and scattering in learning were considered was applied as the analytical technique under the theory of work achievement method where evaluation of learning is made by quantitatively sampling a scatter in individual working time in work. The result is summarized as follows : (1) Analysis of numerical values of the degree of achievement of work learning was carried out at each work by applying the work achievement method. (2) where work learning in the respective work is evaluated by the achievement degree Q, the value of Q is low in the beginning stage of learning but will rise in line with an increase of the number of working days. (3) We prepared a model graph where evaluation of the achievement degree of work learning can be made easily and at the same time established an evaluation standard setting method for work learning suitable for the respective experimental work.

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Sheet metal parts have been widely used in industry and much information for parts has been accumulated in the database. In planning the manufacturing process of a sheet metal part, if the similar process plan of the part to be manufactured can be retrieved from the database, the process planning would be faster and more consistent. In this paper, the effective method of searching the sheet metal parts based on bending process similarity is proposed. This method consists of two stages. First, flat pattern drawings of the parts with the same set-up numbers are classified into several topological structures. Secondly, the parts that possess the bending process similarity with the target part are selected. The bending process similarity is defined by the grasping position of a robot gripper. The number of reposition and grasping positions are decided by taking the geometric element of the flat pattern into consideration. The effectiveness of this method is described and illustrative examples are shown.

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We consider dynamic job shop scheduling problems with a tardiness cost criterion. The most practical scheduling method in dynamic scheduling environments is using dispatching rules. However, there is no dispatching rule that performs best under all scheduling conditions. In this paper, we apply a multi-layer feed-forward neural network to the scheduling, and propose a two-stage training method to minimize the average tardiness cost of jobs under various scheduling conditions. In the first stage, each neural network for its specified scheduling condition is trained separately by a simulated annealing method. In the second stage, a final neural network for all scheduling conditions is trained by a back-propagation algorithm. Simulation results show that the trained neural network outperforms the best dispatching rules in any levels of due-date tightness and job arrival rate.

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This paper presents a scheduling method to maximize total profit as a performance measure in a two-stage flow shop model. The profit is defined as the difference between the revenue and the cost of production, and a scheduling method to maximize total profit is proposed using the Branch and Bound method aiming at maximizing revenue and minimizing costs. This paper compares the optimal schedule which maximize total profit with the optimal schedule which minimize total flow time searched by Johnson's theory. This paper also shows the usefulness and some characteristics of the proposed method through various numerical experiments.

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This study proposes an optimal multi-stage flow-shop model for situations where setup time is affected by machine sequencing. The model enables setups involving independent execution of each process. Various quantitative data lend support to the model's effectiveness and demonstrate in both theory and procedure, an optimized scheduling model in a multi-stage flow-shop through changes in machine sequencing, or setup time. The proposal applied an approximate solution very near to the optimal solution, and resulted in less number of steps than the Branch and Bound method in terms of its branched node value for reaching an optimal solution. The conclusion is that the larger the number of manufacturing processes and products, the greater the effectiveness of this model.

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