It is very important to be able to estimate the critical wind speed of overturning precisely, because railway vehicles are becoming lighter and increasing running speed, which lead to conditions disadvantageous to prevention of railway accidents involving overturning of the vehicle by strong crosswind. Therefore, evaluation of the critical wind speed with consideration on the effect of dynamic behavior of the vehicle is required, that is, the difference between the static analysis and the dynamic analysis is needed to be clarified quantitatively. Thus, in order to analyze the dynamic behavior of the vehicle subjected to crosswind, we constructed a dynamic analysis model which was developed based on the static analysis model, and examined the effect of the frequency of the crosswind on the dynamic behavior of the vehicle. Further, in order to verify the validity of the dynamic simulation program prepared by using the dynamic analysis model, we conducted a full scale experiment applying lateral force to the vehicle dynamically. As a result, it has been verified that the dynamic simulation program is valid for evaluating the wheel load variation of the vehicle which is subjected to crosswind. Consequently, the effect of the frequency of crosswind on the bahavior of the vehicle has been clarified, the critical wind speed of overturning has been evaluated more precisely, and also the difference between the static analysis and the dynamic analysis has been evaluated quantitatively.

View full abstract

A new wheel slide detection and control system is developed for the railway vehicles. Recently, the number of new model vehicles where the anti-lock braking system (ABS) was installed is increasing to prevent the wheel slide that causes increase in the braking distance and damage to the wheel. The ratio of the number of vehicles in which ABS is installed is high in new vehicles, and low in old model vehicles. A new system is proposed to detect wheel slide by two methods, using with the detection of the wheel rotation speed and the difference of the rotation speeds of two wheels. When the wheel slide is detected, ceramic particles are ejected between the front wheels of the foremost bogie and the rails. Ceramic particles increase the adhesion force between the wheel and the rail, and the wheels recover from the sliding condition. The jetting of ceramic particles is monitored by the newly developed particle flow-rate sensor. The effectiveness of the proposed system is verified by the experimental runs using the limited express and the suburban trains. The results show that the wheel slide can be detected at every case and is suppressed within a few seconds. Compared with ABS, the proposed system is simple and less expensive. Thus, the proposed system has large possibility to be installed to wide range of vehicles including the old model vehicles which do not have ABS systems.

View full abstract

A numerical and experimental study is presented to investigate modeling and vibration behavior of a thin rectangular isotropic plate with distributed small holes. Such porous plate (namely, a plate with many small holes) may be used to reduce the total weight in weight-sensitive structures. Up to the present, the modeling technique for the problem has not been established yet due to the difficulty of incorporating effects of relatively small-sized holes in the plate vibration theory. In this report, a method is proposed to analyze vibration of such porous plates by developing a representative plate element where a circular hole is located in the center of the element. Numerical examples include sets of natural frequencies calculated for the porous plates with three different boundary conditions, and the variations of fundamental frequencies are presented with changing the number and location of holes on a square plate. The validity of such computational model is examined by comparing the numerical results with experimentally determined frequencies for aluminum porous plates.

View full abstract

This paper presents the development of RT-Components for assistive robotic arm and man-machine interface with RT-Middleware for disabled patients. RT-Middleware is an open software platform for component-oriented robot system development. The RT-Component is a basic functional unit for constructing a robot system on RT-Middleware. The specification of the RT-Component is standardized in OMG. Therefore the RT-Component can be shared and reused in other robot systems. One feature of a life support robot is that the robot is operated by a human. Therefore a man-machine interface plays an important role for operating the life support robot. Various man-machine interfaces for operating the life support robots have been developed and customized according to the condition and remaining function of the patients. These man-machine interfaces can be connected to the life support robot in the same fashion by making the software modules for the robots and the man-machine interfaces as RT-Component. This paper shows the RT-Components for an assistive robotic arm and a man-machine interface. The robotic arm component receives joint angle velocity or hand velocity as a motion command of the arm from the man-machine interface component, and send the current joint angles to the man-machine interface component via a DataPort. The other basic commands for operating the assistive robotic arm are defined in a ServicePort. We developed RT-Components of several types of robotic arm, and man-machine interface. Any combination of the arm components and the man-machine interface components could be connected in the same fashion.

View full abstract

This paper considers active control of the sound transmission loss of a flexible panel partitioning an open space. A control strategy presented in the work comprises both active and passive control for the purpose of minimizing the total acoustic power transmitted from a panel excited acoustically from the other side, hence hybrid control. As with a passive control strategy, a double-leaf partition method is employed, thereby enhancing the sound transmission loss in the high frequency range. In the low frequency range, on the other hand, active cluster control is introduced in an effort to suppress the sound transmitted power without causing spillover. First, the sound field system produced by a double-leaf wall with air space acoustically excited is described. Cluster control consisting of cluster filtering and cluster actuation is then employed, the system state being expressed. Moreover, the optimal control law for minimizing the total acoustic power radiating from a vibrating panel is derived. A numerical analysis is then conducted, clarifying the control effect for suppressing the transmitted sound power. Finally, an experiment is carried out, demonstrating the capability for enhancing the sound transmission loss using the hybrid control strategy.

View full abstract

Concrete placing in the construction of dam is carried out by tower crane. Shortening the cycle time for the carriage and placing is a very important issue and a variety of feedback control methods have been proposed to avoid the generation of the residual vibration at the placing position. Because both the acceleration in the rotational direction and the centrifugal force in the radius direction act on the hanging load, the dynamics is equivalent to that of a spherical pendulum and the control strategy for the tower crane is much more complicated than for a simple crane whose dynamics is equivalent to a single pendulum. Considering the cost and the breakdown of the measurement hardware, the construction of open loop control method is strongly expected for the practical usage. In this research, we propose a acceleration pattern based on the nonlinear dynamics of the tower crane in the acceleration and realize the antisway open loop control.

View full abstract

This paper proposes a new structure of rotating gyro using magnetic suspension. The new-structured gyro is called magnetically suspended gyro. A rotating gyro based on an active magnetic bearing (AMB-based gyro) has been proposed in order to realize high accuracy, compact and low-cost gyros. However, the miniaturization of the AMB-based gyro is technically difficult because of the constraints of its structure. In contrast, the proposed structure suits miniaturization because of the simplicity of rotor design. Based on the new concept, a prototype of the magnetically suspended gyro was fabricated. The structure, the principle of angular velocity measurement and the control system for magnetic suspension are presented. The performance of the closed-loop system and angular velocity measurement was evaluated. The magnetically suspended gyro was effective in measuring angular velocity below 10Hz although the measured angular velocity signal includes oscillating components. Since such components come from the displacement sensors used for magnetic suspension, the accuracy of the gyro is expected to be higher if the displacement sensors are improved.

View full abstract

This paper is concerned with a new control design methodology for vibration control of flexible structures by the wave control. In the wave control, controllers are usually designed to minimize the reflection coefficient by utilizing the wave analysis. However, because the method is based on the wave analysis, the method has been mainly applied to simple uniform structures. In this paper, to establish a control design method for more complex systems, we propose a control design method based on the impedance matching index, which represents difference of the transfer functions of the closed system and the controller. The index is motivated by the wave analysis and control for uniformly varying ladder networks. Optimal tuning of passive dampers and dynamic absorbers by the impedance matching index is especially considered as a first step for control design. Numerical examples for damped mass-spring systems with auxiliary masses are conducted to show effectiveness of the proposed method.

View full abstract

In this paper, influence of in-plane vibration on building SEA model for flexural vibration on beam-like structures with an arbitrary angle is investigated. We develop the assessment method of the influence of in-plane vibration on the built SEA model for the flexural vibrations on the L-shaped plates. The method is useful to identify the frequency bands affected by the in-plane vibration and how the coupling loss factors are under- or over-estimated. The influence of in-plane vibration on beam structure is a simple compared to the ones of plate structure. A proposed method as mentioned above is effective for the structures composed of two beams connected in an arbitrary angle.

View full abstract

Recently, robot systems which support surgery are actively developed. Especially, microsurjery has attracted attention of people in recent years. However, as current surgery support system cannot present force sense to operators, it is difficult to use pratically. Accordingly, there are many active studies on bilateral control. In bilateral control, the slave follows to the master and the master presents the reaction force that the slave receives. Using bilateral control, it will be possible to present force sense to reduce the movement of hands and to perform save microsurgery. In this paper, it aims at developing of the technology for the transmission of force sense in surgery support system. Bilateral control which conbines position control and impeadance control is proposed for tasks of moving object with two fingered master slave system. Gain of position control and impeadance control can be changed according to the ratio of internal force between master slave system and environment. The force response of the position control and impedance control, and variable gain were confirmed by the experiment.

View full abstract

A novel magnetic type tactile sensor is proposed that can measure a three-axis force and detect slips. Its simple structure comprises two layers, an elastic layer, and a substrate layer. The elastic layer is made of an elastic material and has a cylindrical permanent magnet. The substrate layer is a glass epoxy board and has four GMR (giant magneto resistance) elements and four chip inductors. Each element outputs voltages depending on a magnetic flux density when the elastic layer deforms as the result of contact. A triaxial force and slip detection ae calculated from these outputs. Laboratory experiments have demonstrated the sensor's effectiveness.

View full abstract

This paper deals with the problem of vibration quenching of the system with a limited power supply using a Hula-Hoop, and the results are compared with those reported in the automatic balancer. Following was made clear from the results of experiment and numerical analysis: (1) It is confirmed by the experiment and the approximate analysis using the averaging method that the self-excited vibration such as the one observed in automatic balancer is not capable of generating in this vibration quenching device using a Hula-Hoop. Moreover, considering the characteristic of this device below the resonant frequency, this device is superior to the automatic balancer. (2) This device is very effective in the region exceeding the resonant frequency of the system. (3) Both vibration quenching and energy saving are able to be established by using the bearing with small rotating resistance for Hula-Hoop. (4) The experimental and the numerical results were in good qualitative agreement with each other.

View full abstract

In the field of vibration control, acceleration sensors are widely used as vibration sensors for large-space structures and soft ground. It is preferable to use velocity and displacement additionally. Then, the absolute velocity and displacement sensors are proposed and these can be used as feedback sensors. Up to now, the research, which is about each detected signal's feedback to an air type anti-vibration apparatus with one degree-of-freedom using an absolute displacement sensor, has been carried out. However, the apparatus will be connected each other in order to configure a large isolated table, and vibration modes of the table are selected and distributed in industrial applications. Since the above research is just one example of the applications, some practical applications should be presented more. Therefore, an anti-vibration apparatus with two degrees-of-freedom is controlled with absolute displacement sensors, and its application is verified in this paper.

View full abstract

In the field of positioning control, magnetic actuators such as linear motors have been widely used. However it cannot be used for electron beam exposure apparatus due to the magnetic leak and heat generation. Therefore, positioning control with air pressure actuators is proposed instead of magnetic actuators. The problem of using air pressure actuators is an inactive response with air's compressibility. Therefore, this paper presents the positioning control methods of PDD^2 control, on the condition that servo valve including air system is imperfect integrator, and the speeding of positioning control with perfect 2 d.o.f. control. However, repeatability cannot be conformed due to flow and mechanical disturbances. Therefore, this paper also presents a compensation method of flow disturbance named flow disturbance observer and perfect 2 d.o.f. PDD^2 control with flow disturbance to improve the response of target value. Finally, the repeatability of perfect 2 d.o.f. PDD^2 control with flow disturbance is presented.

View full abstract

Movable structures can change their shape because each of the components are connected by hinges. This paper discussed a mechanism design method that can relocate hinges based on a fourbar linkage mechanism. In this paper, "structural fabric" is defined as the arrangement of the hinges, and "shape" is also defined as the structural externals made from the arrangement of the hinges. By this definition, changes of the shape by the hinge's angle without changing the hinge arrangement is different from changes in the structural fabric. On the other hand, origami can transform by changing its structural fabric because it can freely relocate creases as hinges. However, there have been no rigid body structures that have origami-like characteristics, since there has been no mechanism that can relocate hinges. So we have designed HDRM (Hinge Double Relocation Mechanism) which can relocate hinges, and have constructed movable structures by combining the HDRM. Contents of this paper is as follows; First, a mechanism design requirement that can relocate hinges by the planar linkage have became clear. The design requirement has been expanded to spatial linkage mechanisms which have been named HRM (Hinge Relocation Mechanism), through the mechanical analysis of the spherical quadric crank chain mechanism. Next, the HDRM that relocates hinges in a singular configuration has been invented by adapting the mentioned requirement. The requirement of making movable structures from HDRM has been cleared by solving the Hamiltonian path problem. Finally, from evaluations using kinematical and interference analysis on the 3D-CAD, it has been confirmed that the constructed movable structures can change into various shapes by changing the structural fabric.

View full abstract

This paper describes a health monitoring methodology using a spatial filter design for observation spillover suppression with measures of modal observability. The spatial filter can be realized using a number of sensors attached to a structure that is less than the number of target modes. Measures of modal observability as criteria for designing the optimal filter in an engineering sense have been proposed by the authors. In vibration testing, if it is possible to make the desired spatial filter by adjusting only one sensor location from among many sensor placements, this affords a practical advantage. In this study, measures of modal observability are used to select one sensor location that should be adjusted, and then the desired spatial filter can be designed. Spatial filtering is then performed for the bending vibration of a cantilever beam. In this study, when the mass and rigidity of structures change, this is defined as structural damage. The feasibility of this monitoring methodology for monitoring health and detecting structural damage using spatial filtering is verified by vibration testing of the cantilever beam.

View full abstract

Flexible contact sensor for three-axis load measurement with high load resolution was developed. The developed sensor is composed of skin layer, elastic sphere and load measurement layer. Diameter of elastic sphere is 10mm and the size of developed sensor is 10mm×10mm×10mm. Load measurement layer is composed of upper electrode, PC/VGCF and lower electrode. For the development of high load resolution sensor, PC/VGCF is used for load measurement layer. PC/VGCF is an electric conductive-material dispersed with vapor grown carbon nanofiber (VGCF) and value of resistance of PC/VGCF is changed by load. Therefore, voltage between upper electrode and lower electrode was changed. Normal load, shear load and displacement can be detected by measuring voltage between upper electrode and lower electrode.

View full abstract

Passive running can run by interaction between machine dynamics and environment only. It has the important feature that a stable limit cycle exists. Many studies of passive running are theory and simulation. However, its mechanism is not understood well. It is important for understanding the mechanism of passive running to simplify analysis and experimental model. Therefore, we focus on the passive running of rimless wheel with springs. In this paper, first, we experimentally demonstrate that it can generate the running phenomenon, and show the characteristics of running motion. Secondly, we show the existence of fixed point in a passive running. Finally, we derive its stability by the eigenvalue of Jacobian matrix.

View full abstract

A handshake is an embodied interaction to display human closeness by way of physical contact. To enable a robot to shake hands with a human, we have proposed models that simulate the handshake approaching motion and the handshaking motion by analyzing the handshake motion between humans. These models simulate the approaching motion and the handshaking motion of the human hands during a handshake. However, in addition to the above two motions, smooth transition from the approaching motion to the handshaking motion is necessary to ensure a firm handshake between the robot and a human. In this paper, we analyze the handshaking motion between humans and propose a model to ensure a smooth transition from the approaching motion to the handshaking motion. By using this model, the robot leads the human to the handshaking motion by actively making a leading motion that is synchronized with the start timing of the handshaking motion. Furthermore, a handshake robot system is developed based on this model, and experiments are performed using it. The experimental results show the effectiveness of the proposed model. The robot begins the handshaking motion 0.2 seconds after gripping the human hand, and the direction of motion is determined by the contact height of the robot and human hands.

View full abstract

This paper presents the evaluation of ultra-minimal spout amount from micro-nano pipettes into phospholipid-coated micro-droplets. The micro-nano pipettes can be used for various biological applications, such as single cell analysis. Conventional microinjection with pipettes has been conducted by air pressures. However, the spouting of high viscosity solutions, such as biological protein solutions, is relatively difficult due to the frictional forces between the surface of a pipette and a solution. It is also needed to evaluate the spout amount quantitatively. In this paper, the electro-osmotic phenomenon is applied to spout the high-viscosity biological protein solution. The local spouts of protein solutions, GFP and F-actin, are demonstrated experimentally. The amount of spout solution is quantitatively evaluated from the fluorescent intensity inside a phospholipid-coated micro-droplet.

View full abstract

We aimed to develop an active catheter that could be used safely in human blood vessels. The various types of active catheter were proposed to realize bending degrees of freedom and to select courses at a branch point of a blood vessel easily. Since conventional ones were developed with electric actuator like shape memory alloy or conductive polymer and so on, they might damage the patient by its accidental electric leakage. Now, we proposed a new type micro valve and incorporated it into a water pressure-driven system with multi-degree of freedom, to produce an active catheter that was compact and required no electrical power for operation. We actually achieved to develop this valve by applying hybrid micro stereolithography and produced the active catheter with two bending segments successfully. In addition, we experimentally verified the good operational performance of a prototype.

View full abstract

The purpose of this paper is to propose a novel peristaltic motion actuator for an artificial esophagus using shape memory alloys (SMAs). SMAs are known as functional materials having large deformation characteristics and recovery forces which have the advantage of having large specific output energy to weight. Utilizing this characteristic features, the designed artificial esophagus was small enough to be implanted. The artificial esophagus proposed in this study is composed of two SMA micro coils, a silicon tube which simulates an esophagus, and a set of polyvinyl chloride resin and acrylic plastic for sandwiching the silicon tube. Its closing pressure is experimentally measured, and carrying capacity is verified using pseudo masticated food with controlled switching circuit. Based on their results, its feasibility is discussed.

View full abstract

This paper shows the result of the mechanical loading tests, the leakage tests and FEM simulation of a glovebox window specimen to secure safety of the glovebox containment. The leakage tests were conducted for test specimens that represent one full-scale glovebox resin window panel and panel to flame sealing. In leakage tests, pressure difference and temperature were observed after three deformation mode of frame and two deformation mode of window panel were applied to the test specimens. In numerical simulation, the large deformation FEM analysis was applied to evaluate sealing mechanism of glovebox window. As the results, the glovebox window constructed with the rubber seal and the resin panel shows no leakage lager than 0.1vol%/h with large static deformation. In numerical simulation, two small rips of the rubber seal plays important role on the containment of the glovebox.

View full abstract

A new concept of a tire and suspension evaluation system based on the real-time vehicle dynamics analysis with measured tire force is discussed in this paper. A testing machine was developed by authors following this concept, in which a six degree-of-freedom motion platform was used to realize various contact conditions of the tire. It is well known that the tire characteristics are important factors for the dynamic analysis of an automobile, and the suspension setting has a strong influence to the contact conditions of a tire. Therefore, it is important to evaluate the tire characteristics including the effects of the suspension system. The test results with developed testing machine were compared with the running test results using an actual automobile, and the advantage of the new concept and developed tire-suspension testing machine was discussed.

View full abstract

Intelligent Transport Systems (ITS) have been developing in Japan to smooth the traffic stream and reduce the number of traffic accidents. In this paper, we deal with the effectiveness evaluation of wireless radio communication system that conveys braking information of a lead vehicle to the following vehicles. Using this system, even if drivers in the following vehicles are looking aside, they can notice the start timing of braking of the lead vehicle by way of warning information. Therefore they can immediately return their line of sight to the forward direction resulting in appropriate braking operation. To reveal the effect of the system, we analyzed the probability of not returning the line of sight to the forward direction concerning drivers in the following vehicles. In the analysis the frequency of driver's looking aside and the installation ratio of the system were set as calculation parameters. We revealed that when the installation ratio is under around 0.3, the system does not make sufficient effect on the safety level.

View full abstract

We developed a management system that provides a design process in which the important attributes of the product can be easily incorporated. We developed a design template to express the product information using five types of knowledge, namely, knowledge about product structure, product entity, product function, product constraint, and product design process. To determine a suitable design process, we first compared the design template of existing products with the product being designed. We calculated the consistency between the two models. From the results of the consistency calculation, we selected and extracted the available knowledge. We created a new design process by using the knowledge extracted from the design template. Finally, we evaluated the process from three perspectives: the ease with which the customer requirements could be reflected, the level of difficulty of the design conflict problem, and the level of difficulty of the design loop problem. Based on the results of this evaluation, designers can select a process to design a new product. We developed a prototype system and used it to design an ocean thermal energy conversion (OTEC) system. The design knowledge for an actual OTEC design was adequately represented by the proposed design template. The most important attribute has a higher value in the design process obtained using the proposed management system process than in the existing system. The proposed management system yields a design process that can easily reflect customer requirements.

View full abstract

In the scheduling problems of the manufacturing systems with human operators, it is not easy to consider variation of machining time which are different from operator to operator. New scheduling method is proposed, in this paper, to consider the statistical distribution of machining time executed by human operators. It is assumed that the machining time executed by human operators are obtained by normal distribution. The proposed scheduling method consists of two steps. In the first step, the sequences of machining operations are determined for the individual machining tools by using utility value based method. In the second step, the candidate human operators are allocated to the individual machining tools taking into consideration of the statistical distribution of the machining time of the individual human operators. The scheduling system is also developed to carry out the proposed scheduling method by using machining time database. Some case studies have been carried out to verify the effectiveness of the proposed method.

View full abstract

Influence of wafer edge profile on performance of Shallow Trench Isolation Chemical Mechanical Polishing (STI-CMP) process for semiconductor manufacturing was investigated. Finite Element Method was used to calculate the contact pressure on the wafer surface, and the removal rate was estimated based on the calculated contact pressure. As a result, shortening the edge width was confirmed to achieve flatter distribution of the contact pressure near the wafer edge. And wafer edge profile controlling is proposed as an effective approach to satisfy the requirement of the edge exclusion. Suitable Roll-Off Amount (ROA) and edge width are also forecasted for STI-CMP process in the next generation semiconductor manufacturing. To meet the specification for the generation of hp=35nm with 1.5mm edge exclusion, the edge width would be below 300μm and ROA would be bellow 100nm.

View full abstract

In the deep drawing, the low blank holder force (BHF) will cause the wrinkle, while the high BHF will result in the tearing. Therefore it is important to determine the appropriate BHF in the forming. In this paper, the variable blank holder force (VBHF) approach for the deep drawing is employed. The simple closed-type algorithm is developed to obtain the VBHF trajectory. The proposed algorithm is roughly divided into two phases. The objective of first phase is to check the wrinkle and the tearing. In this phase, the low BHF, which causes the wrinkle, is used as the initial BHF. The BHF is increased in order to avoid the wrinkle. The algorithm will be terminated when the tearing occurs. The distance between the die and the blank holder is used to measure the wrinkle. Then, the second phase is considered. The main objective of second phase is to examine the thickness deviations. It is expected that the BHF will be decreased by considering the thickness deviation. The wrinkle is also checked in the second phase. By iterating above two phases, the VBHF trajectory can be obtained. One of the advantages by the VBHF is to reduce the forming energy. The validity is examined through the numerical simulation and experiment.

View full abstract

The objective of this research is to develop a center-less gear lapping machine which can simultaneously make all tooth flanks of a steel gear smooth as a maximum peak-valley height (Rz) of less than 1μm in a short time without fixing it on any shaft. A work gear is meshing with two lap gears as crossed helical gears and supported by a guide gear during the lapping. The two lap gears and the guide gear are nylon gears. Lapping slurry containing abrasive grains is supplied to the meshing teeth. This paper shows the mechanism of the center-less lapping process and the structure of the lapping machine designed and manufactured by the authors. The behavior of the work gear and the removal amount are investigated during the process. Moreover, the work gears lapped using the new machine are evaluated with regard to the tooth roughness and the accuracy of the tooth profile. The life of nylon lap gears is also evaluated.

View full abstract

In order to investigate the durability of the sliding parts of machinery, it is important to know the force acting on such parts and to evaluate their stress distribution. However, the actual contact stress distribution differs from the theoretical one, as in the case of the gear tooth flank. This is caused by inaccurate assembly and deformation or slant of the shaft and the bearing housing that supports the gear unit. Therefore, it is important to know the contact stress distribution on tooth flanks in the actual gear unit. The authors applied thin-film pressure sensor technology developed to measure the oil-film pressure distribution of engine sliding parts. In the present study, a thin-film pressure sensor with a thickness of approximately 6μm and 5 point sensing parts was developed and deposited along the tooth flank on the pitch circle to measure the axial pressure distribution between meshing tooth flanks. Afterward, the measured and calculated results were compared. The measured pressures were much higher than the Hertzian pressures, and were distributed unevenly along the tooth trace. Thus, it seems to have been caused by crossed and parallel misalignments and also by the shape of the tooth flanks.

View full abstract

CVD diamond films are expected to become a solid lubricant coating without any maintenance. However, substrates on which diamond film can be deposited are limited to silicon, tungsten carbides (TiC) and so forth. If diamond films can be deposited onto steel substrates, possible applications will increase in number. In this study, diamond film was deposited on a steel substrate with an interlayer and was partly polished. Tungsten and titanium were selected as materials for an interlayer between the diamond film and the SUS 440C substrate. In a friction test, low and stable friction coefficients were obtained between the pair of diamond film and SKD 11 pin, with a friction coefficient of 0.1 in the steady-state regime. The diamond films on steel substrates show good friction properties similar to conventional diamond films on TiC substrates. Therefore, diamond films on steel substrates prove useful in obtaining solid lubrication films for sliders.

View full abstract

Recently, by development of double balloon and capsule endoscopes, small intestinal whole area observation was enabled. However, it is difficult to use these endoscopes in patients with intestinal obstruction and adhesion. We developed a new endoscope that can be used in patients with intestinal obstruction and adhesion; this instrument consists of an ileus tube and an optical fiberscope (diameter, 1.1mm). The complete observation of small intestinal is to be planned by controlling internal pressure of balloon in ileus tube, and pulling the tube out at constant speed. In our previous study, we have developed an internal pressure control device which consists of a balloon of ileus and an industrial cylinder, and we confirmed the utility. In this study, we developed a new control device combined with a general medical syringe, which enables to be sterilized easily and also to give less anxiety to patients. As the results of performance experiment of the device, the control accuracy was within ±0.5% error. Furthermore, in a disturbance response, the pressure fluctuation was limited down to 12%, compared with a case without any control.

View full abstract