We have designed and fabricated three-dimensional (3D) stages driven by electrostatic comb actuators. The stage consists of traveling tables, suspensions and comb actuator(s). The key to realizing 3D motions is in the geometry of the suspensions, which incorporate a pair of leaf springs inclined to the substrate. First, the motions of the stage were analyzed by FEM (finite element method). Then 3D electrostatic stages were fabricated on an SOI (silicon on insulator) wafer. Finally, after examining the relation between the vertical and lateral displacements and driving voltage, surface topography was observed by using an AFM that was equipped with the 3D electrostatic stages as the scanner.

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In this paper, we have investigated the pull-off forces between the surfaces having periodic asperity array. First, an FIB (focused ion beam) was used to create periodic asperity array on each surface on glass sphere glued on cantilever tip and silicon wafer. Then the pull-off force on the silicon asperity was measured by using the glass sphere with/without asperity array. The results showed that the pull-off force was decreased by applying the asperity array to both silicon and glass surfaces than applying on only the silicon surface. The pull-off forces changed when shifting the relative angle between each periodic asperity array.

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The tribological behavior of micro mechanical systems plays a key role in the performance of such systems. Consequently, it is necessary to quantitatively understand the friction and wear properties in ultra minute region because the influence of the surface topography and the atmospheric gas can't be disregarded for making the component minute. Especially, external disturbance, i.e. vibration may promote fretting, which have been hardly studied in nano/micro-scale. In this paper, we investigated the influence of the relative humidity and the normal load on nano-scale wear. The sliding surface was measured by AFM after tests. The test materials of single-crystalline <111> silicon plates were rubbed against a tip made of SiN at load ranging from 20nN to 1OOnN. When the slip occurred, a protuberance was observed on the Si plate. The protuberance volume increased with increasing sliding amplitude, relative humidity and normal load.

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For fluid microactuators and microfactory, the authors have proposed a novel high output micropump using inertia effect of fluid which has a pipeline element in place of an outlet check valve and verified the effectiveness with a fabricated micropump. To increase the output power and to miniaturize the size, this paper investigates the optimal structure through simulations based on the proposed simple mathematical model with lumped parameters and experiments using fabricated micropumps with different sizes of the pipeline element. Also, the optimal diameter of the diapharm is investigated through simulations.

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This paper reports the development of micro motors using Electro-Conjugate Fluids (ECFs). ECF is a kind of dielectric fluids, which produces jet-flow by applying high DC voltage between electrodes inserted in the fluid. By applying the phenomena of ECFs to motor driving principle, simple structure and lightweight micro motors can be realized. We call these motors ECF micro motors. In this study, we designed and fabricated φ5mmI.D. 4-layered and 8-layered DP-RE-type ECF micro motors are miniaturized in order to improve the output power density. Also we investigated the characteristics by experiment in the case of using high performance ECF in order to confirm possibility of improvement of output characteristics. In conclusion, it is confirmed that it is effective to miniaturize ECF micro motor and use high performance ECF for improvement of output characteristics.

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Electro-Conjugate Fluid (ECF) is a kind of dielectric fluids and a kind of functional fluids, which produces jet-flow(ECF-jet) by applying high voltage between electrodes. The ECF-jet generated between needle-type electrodes and ring-type electrodes is called ECF-jet with needle-type electrodes. It is ascertained that the pressure due to ECF-jet with needle-type electrodes is increased by miniaturizing dimensions of the electrodes. The characteristics are suitable for microactuator. Therefore, the purpose of this study is the realization of novel micro manipulators driven by ECF-jet. In this paper, first, characteristics of ECF-jet with needle-type electrode are experimentally investigated. Second, a novel microactuator which is actuated by the same principle as well-known Bourdon tubes is fabricated. Third, static characteristics of the microactuator is experimentally investigated. Finally, another type microactuator, two-degree-of-freedom micro ECF manipulator is fabricated. Future works are fabrication and investigation of a microhand constructed with more than three micromanipulators.

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An electro-conjugate fluid (ECF), which generates powerful jet flow under high voltage supply, is a kind of functional fluids. The fluid is suitable for micro actuation. In this study, we develop a new type of plate-type micro diaphragm pump driven by ECF. We propose the driving principle of the micro pump, and fabricate a prototype of the pump. The Experimental results confirm the usability of the micro pump.

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A novel hydraulic actuator named the "MR cylinder"' is proposed and developed. The actuator is composed of a piston with electromagnets and a cylinder. MR (Magneto-Rheological) fluid that is a functional fluid whose apparent viscosity can be controlled through the applied magentic field flows in the gap between the piston and cylinder and the differential pressure is controlled by the current applied for the electromagnets. The proposed actuator features compactness and large stroke. In this paper, the MR cylinder is proposed, fabricated and applied for a 2-link manipulator. The static and dynamic characteristics of the MR cylinder-driven manipulator is investigated experimentally.

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A small sized servo actuator with high output torque at low rotation speed has been developed for applications to servo driving of micro-machine such as micro-robots. It consists of a Brushless motor and planetary gear drive. In this report, each element technology, output characteristics of the actuators are described. The planetary reduction gear drive has six micro-gear and planet carrier with 3K-type mechanical paradox. A prototype actuator is 13.5mm in diameter and 40mm in length, the planetary reduction gear drive is high reduction ratio of 1/243.

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The previous paper reported on the nutation motor which used air pressure or electromagnetic. In this paper, we report a new type nutation motor of φ10 diameter, named φ10 pneumatic nutation motor consisting of a diaphragm which has some pneumatic rooms, a rotary bevel gear and a fixed bevel gear. Injecting air into each pneumatic room sequentially causes nutation of the rotary bevel gear, which makes the output shaft to rotate through the bevel gears and spherical bearing. In this report, first, the driving principle and design of this motor are presented. Next, the prototype of φ10 pneumatic nutation motor is fabricated and tested. The feature of φ10 nutation motor are (1) simple structure, (2) realization of φ10 diameter, (3) low noise and low vibration, and (4) limitless low speed operation.

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An optical three-axis tactile sensor is comprised of a silicone-rubber sheet, an acrylic plate, a CCD camera and a light source. A silicone-rubber sheet has an array of 8×9 sensor cells consisting of a columnar feeler and conical feelers. In the present paper, the authors evaluated a new sensing element having a columnar feeler and 8 conical feelers proposed in the previous paper. For the sensing element, normal and shearing forces are calculated from integrated gray scale value and centroid displacement caused by conical feeler's contacts. In the present experiments, the tactile sensor was mounted on an articulated manipulator and the manipulator scanned on precise abrasive paper. It was found that obtained shearing force increased with increase of particle size of the abrasive paper and degreased with increase of scanning velocity. Contrarily, in the case of Teflon tape, shearing force was almost constant in spite of velocity increasing. The above-mentioned results show grinding phenomena discussed on theory of machining and Coulomb friction caused on dry surface.

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In order to cause a tactile sensor to be thin shape, a new optical tactile sensor is developed by applying CT(Computed Tomography) algorithm. The present tactile sensor is comprised of infrared emitting diode array, the receiving phototransistor array and transparent silicon rubber plate. Infrared rays emitted from the diode array are directed into an end of the plate and their intensity distribution is measured by the phototransistor array mounted on the other end. If CT algorithm is directly applied to the tactile sensor, there are two defects such as shape of sensing area limited to a circle and long calculation time. Thus, a new CT algorithm oriented to tactile sensing is proposed to overcome these defects. In the present algorithm, a square sensing area is divided to an n-by-n array and algebraic equations are derived from relationship input and output light intensities on assumed light projections. Several reconstruction methods are considerable to obtain pressure values caused in the squares. In the present study, ART(algebraic Reconstruction Technique) and LU decomposition methods were employed and these methods were compared to select the best reconstruction method In a series of simulations, it was found that the ART had an advantage for the present typed tactile sensors' reconstruction method because of variability of calculation error.

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This paper describes a compensation device for joint motion errors, elastic displacements of the joints and links, and thermal deformations of the links. This device employs two rods connecting with the joints and a scale unit. The scale unit can measure the variation of the distance between the joints independently of the external load because the rods aren't subjected to the load. Moreover, temperature fluctuation has little effect on measured variation because the rods and the ball shank used in the spherical joints are made of Super Invar. This device was built in the experimental extensible limb of a coordinate measuring machine for micro parts. Experiments show that the device improves the stiffness and decreases the thermal expansion of the link.

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In the present paper, singular point of in-parallel actuated mechanisms at which connecting chain has local mobility has been investigated. Based on inverse kinematics, the presence of such singular point has been revealed. Kinematic relationship among output velocity and joint velocities of both active and passive joints in the connecting chain that has local mobility has been derived. A method of trajectory planning considering kinematic characteristics at the singular point has been shown. Numerical examples of a planar in-parallel actuated mechanism with three dof have been shown and discussed.

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The triple arm mechanism is simple and basic spatial parallel mechanism with three degree of freedom which consists of a base link, coupler link and three two-link-chains having the actuated prismatic joint. In previous paper, we analyzed the sensitivites with respect to the kinematic constants which indicate the orientation of the rotational axes of the revolute pairs to consider the clearance of the revolute pair. And measuring the fluctuation of output angle caused by external force experimentally, we found the practical workspace of the movable platform is different with the one obtained from the analysis. In this paper, we report the method for the static analysis of this this type of parallel mechanism using massless free-body diagram. We show that the kinematic constants are changed by the weight of movable platform experimentally. And we confirm this phenomenon with results of the static analysis. Then, we estimate the cause of that difference between practical workspace and analytical one.

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This paper deals with development by way of trial for a new pivot bearing having three degrees of freedom. The idea of this pivot bearing is based on a continuous velocity joint (CVJ). At first, I achieved the 3 degrees of freedom using ball bearings. But it was big size compared with a bearing with 2 degrees of freedom. By improving internal structure, it was achieved that the 3 degrees of freedom by size the same as a 2 degree of freedom bearing.

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A new surface mount system with a parallel arrangement of miniature manipulators was proposed for use in system down sizing. The miniature manipulator consists of a molded pantograph mechanism, which is composed of large deflective hinges and links, both made of the same materials. The complex and dynamic loads, that is, a combination stress of bending, tensile, compression and shearing stresses, occurs on each hinge in the pantograph mechanism. In these stresses, a hypothesis that bending and tensile stresses are the major factors in the fatigue damage of hinges is set up. On the hypothesis, tensile-compressive and bending conditions with hinge specimen as a fatigue test are carried out. The hinge specimen is made by the injection molding machine, and its material is polypropylene (PP) or the combination of PP and ethylene-propylene-rubber (EPT). By the fatigue test, the durability of hinge made of each material and the damage advance inside of the hinge are investigated experimentally.

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In this report, at first, an ultrasonic heating method is proposed as a suitable way for an inflatable maicromanipulator made of shape memory polymer. The inflatable micromanipulator has a simple tubular body made of shape memory polymer(SMP). A manipulator joint bends with asymmetric inflation of a SMP tube caused by point heating on a tube wall and pressure loaded into the inside of the tube. Ultrasonic absorbent materials of polymer or special structures working for ultrasonic absorption are located on a wall of the SMP tube at the bending joint. Ultrasonic waves propagate from a vibrator into a liquid phase inside of the SMP tube, and the absorbent absorbs ultrasonic energy and heats up. Next, We conducted model experiments using ultrasonic waves with tens kHz order, mm sized heating targets of several polymer materials, and silicon oil as a propagation medium for investigation of characteristics of the ultrasonic heating method. From experiments it is clarified that bubbles generated by ultrasonic cavitation around a target largely effect on heating up the target. And also, the bubbles affect on thermal stability of the target. At last, we show that microballoons mixed in a target improve the thermal stability.

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In designing the self-organization robot, researchers show the policy which manufactures the as much as possible small and light robot. By this designing, it is possible to drastically reduce the production cost, and raise composition degree of freedom per unit product and holds the size of the whole self-organization robot. Therefore, transfer method for enabling the transfer between robots only in the opening and closing operation wall of the robot is proposed without using wheels and crawlers, transfer legs, etc. in this paper.

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In this paper, to realize handling of micro-parts, which size is smaller than 1mm cubic, the generating mechanism of sticking-force on micro-parts is analyzed. And using experimental apparatus and test micro-parts, the sticking-force is measured in an atmosphere. It is proved that the sticking-force P1 depends on the pressing-force which value is limited some by conditions. And using over limited pressing-force, the sticking-force P2 has a constant value. That force P2 is similar to the theoretical molecular force between silicone-part and silicone-plate. That force P2 depends on a perimeter of testing micro-part, however there is no pressing-force, the sticking-force P0 is independent of the scale factor.

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Recently, metal elements doped DLC films were developed in order to improve the adhesion property and the lubricity. In this paper, lubrication mechanism of Ti doped DLC films were discussed with the results of friction test and surface analysis. The sliding surfaces were analyzed by using the TOF-SIMS. In case of ZnDTP+MoDTC was used, large amount of sulfur and molybdenum was detected in wear track of Ti-DLC by TOF-SIMS analysis. On the other hand, small amount of sulfur and molybdenum was detected in wear track of CVD-DLC. Therefore, it is reasonable explain that MoS_2 was generated by tribochemical reaction of ZnDTP and MoDTC on wear track of Ti-DLC, and is indicate more low friction than CVD-DLC.

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Al_2O_3-BaF_2-CaF_2 composites containing SiO_2 as a sintering additive were prepared using spark plasma sintering, and their high-temperature tribological properties were investigated. After sintering blended Al_2O_3-BaF_2-CaF_2-SiO_2 powders, BaAl_2Si_2O_8 phase was formed. The volume fractions of BaAl_2Si_2O_8 and BaF_2 phases increased and decreased, respectively, when the particle size of Al_2O_3 powder and the amount of SiO_2 powder added to the composites were increased. Adding only 1wt% SiO_2 to the Al_2O_3-BaF_2-CaF_2 composites improved their wear properties without getting their friction coefficients increased.

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Al_2O_3-based self-lubricating composites have attracted much attention because they may be applicable to high-temperature mechanical elements. In this study, Al_2O_3-based self-lubricating composites containing CaF_2 as a solid lubricant and SiO_2 as binder were prepared by spark plasma sintering, and their tribological properties were investigated using a SRV testing machine from room temperature to 800℃ in air. The tibological effects of Al_2O_3 grain size on the composites were also examined. It was shown that adding SiO_2 to the Al_2O_3-based composites reduced their friction coefficients and wear rates above 600℃. The friction coefficients of the Al_2O_3-CaF_2-SiO_2 composites were reduced from room temperature to 800℃, by increasing the Al_2O_3 grain size.

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To clarify leakage characteristics of the flat metallic gasket, the leakage rate of a gas and real contact area of the seal surfaces were measured under several closing loads. As the closing loads increased, the leakage flow in the radial direction ceased and only the leakage flow in the circumferential direction remained. To determine the closing load at which the radial leakage flow cease, the real contact situation on the gasket surface should be observed. In this paper the real contact area between the copper gasket and the steel flange was measured using the thin polymer film of 1 μm in thickness. As a result the contact pressure over which the radial leakage ceased could be predicted from the observation of the thin polymer film. In addition, the cross section of the aperture for the leakage flow in the circumferential direction was evaluated from measured real contact area, and the leakage rate was estimated by the assumption of laminar flow. It agreed well with the measured leakage rate.

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Pin-on-disk type wear tests of 0.35 % C steel in contact with itself were conducted in moist air at various contact loads under dry sliding. The friction and wear were measured continuously throughout the tests. After the tests, the relationship between friction and wear and the difference in properties of the wear surfaces were investigated in each wear mode. The phenomenon of zero wear appears in the early period when the tests are conducted at very low loads. The zero wear continues for a long sliding distance and then changes to mild wear. The specific wear rate is constant irrespective of load in the mild and severe wear regimes. The atomic mass percentage of oxygen and coverage of oxidized surface film on the wear surface of disk increases with sliding distance.

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In a machine design, a carbon system thin film is beginning to be used from a viewpoint of the cost reduction by the formation of a long-life life. However, coatings hardness and the relation of cost were not considered. This is considered to be for the hardness of a thin film to be dependent on coating equipment and the coating method. Then, in this research, the hardness of a carbon system hard thin film and the relation of cost are proposed as a new view. The conventional coating method of the CN_X (amorphous Carbon Nitride) film expected as a hard thin film was improved from the cost side, and the thin film which has hardness equivalent to the former was created.

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In this paper, it is proposed to use a new type of solid particle impact test (slurry jet) to swiftly evaluate wear properties of thin, single layered or multilayered coatings. By the slurry jet, 1.2μm alumina particles were impacted at high velocity perpendicular to thin PVD coatings of TiN deposited on high speed steel substrate materials under various temperatures. Since the coatings have a much higher wear resistance than the substrate material, the wear rate increases significantly to the higher level of the HSS material when the coatings are penetrated. This is utilized in the quantification of the assessment of coating wear. A ranking of wear resistance and correlations to the coating surface hardness measured by nano-indentation tests, and coating quality as revealed by XRD half value breadth analysis is given and discussed. For the coatings included in this study, the TiN deposited under the highest temperature proved to have the highest wear resistance although it had a relatively low hardness.

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Surface modification of WC-10 wt. % Co cemented carbides was carried out with fine particle beam ejecting. Silicon carbide abrasives and fly ash particle were ejected with jet stream for the modification. The effect of the modification was evaluated form the change of the toughness and hardness measured by Vickers indentation technique. Experimental results showed that the toughness of the cemented carbide increased significantly by the fly ash particle ejecting.

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Plasma Enhanced coatings such as sputtering and PECVD (Plasma enhanced chemical vapor deposition) are widely used for improving the surface tribological properties of mechanical parts. However, the coating to a complex shape including the inner walls of a long narrow tube is much more difficult than that to a simple plane, because it is hard to generate the high-density and uniform plasma along the surfaces of such a complex shape. In this study, we developed a new microwave-enhanced sputtering source for the coating to the inner walls of a long narrow tube. The high density (>10^<11> cm^<-3>) plasma was ignited at an input power of no more than 28 W at a pressure of 0.1 mTorr.

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In order to reduce the environmental impact, the low viscosity oils have been required to apply for engines. However, the too much low viscosity will cause the decrease in oil film thickness between the piston and the cylinder. Therefore, we need to know tribological properties of engine using the low viscosity oil. In this study, we prepared 4 type commercial oils (WO-20, W5-30, W10-30, W20-60), friction and wear properties were investigated by the block on cylinder type frictional device. Viscosity dependence of the coefficient of friction, change in oil film thickness with increase in sliding velocity and PV-diagram will be discussed.

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Effect of oxide formed on friction behavior of aluminium alloy during fretting were studied. The ambient pressure was varied from 10^<-3> to 10^5 Pa. The experiments were carried out at a normal load of 1 N, a slip amplitude of 100μm, a frequency of 3 Hz and 10^4 cycles. It was found that coefficient of friction became minimum at 10^<-1> Pa. In order to examine the formation and removal of oxide debris particles on the wear scar, another experiments were carried out in which the ambient pressure was changed alternately from 10^5 to 10^<-3> Pa for every 2×10^3 cycles. Coefficient of friction is lower at 10^<-3> Pa than at 10^5 Pa. That is because oxide remained on the surface prevents the strong adhesion at 10^<-3> Pa and oxide particles behaves as abrasive at 10^5 Pa.

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