For the fields of robot's sensing, developing artificial arm and leg, and investigating surface property, the sensor that is applicable to response for shear force as well as normal force should be developed. Our developed haptic sensor by combining metal particles in balloon natural rubber has high quality of sensing at 0.01 N ordered force and has the ability of responding at the case of rubbing any bodies. The rubber involves MCF as one of intelligent fluids, and therefore is called MCF rubber. Because of making the rubber more sensitive to the shear force, the fingerprint is also shaped on its surface. The sensing of the MCF rubber is more responsive at the rubbing on a sandpaper than the commercial feeling pressure conductive rubber. The MCF rubber has correlation between the electric current flowing inner the MCF rubber and the surface roughness of the rubbed body.

View full abstract

   For the fields of robot's sensing, developing artificial arm and leg, and investigating surface property, the sensor that is applicable to response for shear force as well as normal force was developed. Our developed haptic sensor by combining metal particles in balloon crude rubber has high quality of sensing at 0.01 N ordered force and has the ability of responding at the case of rubbing any bodies. The rubber involves MCF as one of intelligent fluids, and therefore was named MCF rubber. Because of making the MCF rubber more sensitive to the shear force, the fingerprint was shaped on its surface. The MCF rubber sensor can grasp the change of the electric current according to the different surface conditions of various types of the rubbed bodies. In the present study, it is clarified that the MCF rubber is applicable to various fields as haptic sensing: silicone gel, paper, clothe, human skin and fruit surface as well as sandpaper.

View full abstract

   At the fields of robotics and sensing for artificial arm and artificial leg, MCF rubber that is able to response for shear force as well as normal force was developed. Our developed haptic MCF rubber by combining metal particles in balloon crude rubber has high quality of sensing at 0.01 N ordered force. From the high sensitivity, the rubber can respond to the shear force. We can clarify that there are elastic and non-elastic regions under the shear deformation of the rubber from the results of friction coefficient. The relation among the electric current flowing inner the rubber, shear and normal forces is respectively linear at the each regions as well as at the bundle of the regions.

View full abstract

   At the fields of robotics and sensing for artificial arm and artificial leg, the rubber that is able to response for shear force as well as normal force was developed. The developed haptic MCF rubber by combining metal particles in balloon crude rubber has high quality of sensing at 0.01 N ordered force. From the high sensitivity, the MCF rubber can respond to the shear force. By rapping the MCF rubber with a silicon oil rubber whose one surface has fingerprint, MCF rubber sensor was made. The present study clarifies the effect of the fingerprint on the electric current flowing inner the MCF rubber. The effect is changed by shape and thickness of the fingerprint, elasticity of the silicon oil rubber, and initial normal force on the rubber sensor. We obtained the optimal shape of the fingerprint.

View full abstract

   At the fields of robotics and sensing for artificial arm and artificial leg, the sensor that is able to response for shear force as well as normal force was developed. The developed haptic MCF rubber by combining metal particles in balloon crude rubber has high quality of sensing for 0.01 N order normal force. The MCF rubber is rapped by silicone oil rubber with fingerprint as a sensor. The sensor has the response of the electric current flowing inner the MCF rubber to the shear, the normal forces and crook motion. In the present, we dealt with the walk and pushup motions of robot having the MCF rubber sensor as the case of active work by normal force on the sensor. We clarified the effects of fingerprint, thickness of the MCF rubber, thickness and softness of the silicon oil rubber cover, and position of electrodes on the electric current flowing inner the MCF rubber.

View full abstract

   At the fields of robotics and sensing for artificial arm and artificial leg, the sensor that is able to respond for shear force as well as normal force was developed. The haptic MCF rubber developed by combining metal particles in a balloon crude rubber has high quality of sensing for 0.01 N ordered normal force. The MCF rubber is wrapped by silicone oil rubber with fingerprint as a sensor. The sensor has the response of the electric current flowing inner the MCF rubber to the shear, the normal and the flexural forces. In the present, we dealt with the thrust, rotation and crook motions of robot having the MCF rubber sensor as the case of active work by shear or flexural force on the sensor. We clarified the effects of fingerprint, thickness of the MCF rubber, et al. on the electric current flowing inner the MCF rubber.

View full abstract

   This paper is concerned with the locomotive characteristics and the structure dynamics of some arthropods. The locomotive motions of some insects were studied using a high-speed video camera system. The walking, jumping, and swimming movements of some arthropods were analyzed from the viewpoint of dynamics. The structural properties of some arthropod organs were also studied using a color 3D laser scanning microscope. Some functional principles underlying arthropod organ design were revealed by the microscopic measurements and movement analysis of arthropods.

View full abstract

   This paper is concerned with the plant hydrodynamics on the opening and closing of a flower head. The capitulum movement was observed with time-lapse photography technique. The morphological structure of petal and leaf surface was studied experimentally. The microscopic observation of the petal surface and the surface of involucral scale was performed using the three-dimensional laser scanning microscope. The time variation in surface roughness of the dandelion and catsear petals was revealed. The variation in surface roughness composed of surface cells was interpreted from the viewpoint of the plant hydrodynamics.

View full abstract

   In this study, damping force properties of damping force variable damper using magnetic functional fluid which consists of nanometer-size and micrometer-size magnetic particles, poly-alpha-olefine, smectite and alpha-cellulose are investigated experimentally. It is shown that the magnetic functional fluid becomes light by containing the alpha-cellulose. Then the damping force of the damper using the magnetic functional fluid becomes large by containing the alpha-cellulose.

View full abstract

   Superconducting oscillation having a relatively small amplitude continued for a long time, unlike the linear damping oscillation of a typical viscosity. This research is conducted to investigate the changes in periodic damping for a levitated magnet by encompassing a levitated magnet with a magnetic fluid for the purpose of suppressing oscillations, in order to optimally use the advantages of levitating superconductors. Damping oscillation of a permanent magnet encompassed with magnetic fluid above a high temperature superconductor was measured using a laser displacement meter. The oscillation of the magnet encompassed with the magnetic fluid subsided in a significantly shorter time than the oscillation obtained in the case when only the magnet was used. Furthermore, the oscillation was faster converge than when the same amount was in a solid state (frozen magnetic fluid). These results confirmed that damping occurred because of the fluidity and the viscosity of the magnetic fluid. A comparison of the waveform of the magnet encompassed with the magnetic fluid and the calculated waveform of the linear oscillation revealed that they were almost identical. It was clear that the properties changed to something different as compared to the damping properties in the case when losses occurred from the pinning effect, because of the magnetic fluid.

View full abstract

   In this study, we investigated the shape of polished surface when imposing DC magnetic field and pulse magnetic field in order to obtain basic data on the surface polishing utilizing magnetic compound fluid (MCF) as a magnetic responsive fluid. We performed polishing experiments for a brass disc by using surface polishing apparatus which can impress pulse magnetic field. We clarified that the shape of polished surface is different between in the cases of DC magnetic field and pulse magnetic field. The polished surface is smoothed along radial direction with a wide region at the case of 0.1 Hz magnetic field. The profile curves are thought to reflect the distribution of magnetic clusters related to the polishing. The pressure distribution on the surface of the polished workpiece were measured. Based on these results, the time change of magnetic clusters distribution on the polishing was clarified.

View full abstract

   The purpose of this study is to propose the micro processing method for inner wall tube with difficulty of cutting its material and to investigate its processing characteristics. The magnetic compound fluid mixed with abrasive grains is poured into a tube, and a ring-shaped permanent magnet stacked in the processing tool is inserted and rotated in the tube. The changes of their internal diameter, their circularity and their material removal were investigated using the tool with different length of the magnet. In addition, in order to clarify the processing mechanism, we performed processing experiments without reciprocating motion of the tube and the visualization experiment. We clarified that the internal diameter increases and the material removal changes proportionally at time. After processing the surface became like a mirror. Judging from processing experiments and visualization experiments without reciprocating motion, the tube may be processed by abrasive grains that are retained on the magnetic clusters at the side of the permanent magnet.

View full abstract

   Magnetic compound fluid (MCF) polishing process is a fine polishing process that has been applied to a large variety of materials, ranging from soft optical polymers to hard ceramics. With the help of magnetic field, non-magnetic polishing abrasive particles are carried by carbonyl iron particles (CIPs) and remove material from the surface being polished. Knowledge of the MCF slurry behavior and forces acting is essential to comprehend the material removal mechanism. To clarify the MCF slurry behavior under a dynamic magnetic field, investigations are carried out to study the variation process of external slurry shape and the effects of process parameters (magnet revolution radius r, magnet revolution speed n_m and supplied MCF slurry volume v) on the slurry terminal shape formation time T and the diameter W and the maximum height H_max of the terminal slurry shape. MCF slurry with clear-cut shape is achieved and the shape is repeated with the revolution of magnet. The magnet revolution radius r shows significant influence on the slurry behavior. Mechanical characteristics of MCF slurry: normal and shearing forces under the dynamic magnetic field are measured and effects of MCF carrier rotation speed n_c, magnet revolution speed n_m and working gap Δ on polishing forces are investigated. The working gap Δ makes considerable contribution on polishing forces.

View full abstract

   This paper presents fundamental study of the displacement measurement using square marker and the field test results of deflection of the bridge in service. For fundamental study, the influence of the shape of maker, the gradation value of maker image and the distance for taking picture on measuring error were investigated. Then, digital image correlation method was compared with square maker measurement in relation to measuring the displacement of target. As a result, square maker measurement had high accuracy with average of absolute error was less than 0.05mm, it wasn't influence by gradation value, and square maker measurement was more robust than digital image correlation method outdoor. In the field test, a bridge was loaded by a dump car which was 20ton in gross weight and the loading point was changed in 2m, 4m, 6m and 8m. Five kinds of the square maker with different sizes and shape were set on felloe guard. Then square maker was compared with the displacement transducer in order to evaluate the accuracy of measurement. It is shown that square maker was able to measure the deflection of bridge up to a practical level even if illumination changes every hour.

View full abstract

   We investigated the removal mechanism for fine particles from a surface using a high-speed air jet. Generally, it is difficult to remove fine particles of the order of micrometers by the impingement of simple air flow because they strongly adhere to the surface by van der Waals force and remain immersed in the viscous sublayer of the air flow. To overcome this issue, we developed nozzles with triangular cavities that add strong velocity and pressure fluctuations to a high-speed air flow. Previously, we reported that the fluctuations generated in the cavities improved particle removal. In this study, we designed nozzles with a narrower gap width containing cavities, which provide high performance and require a lesser flow rate for efficiently cleaning large surfaces. Experimental results show that the newly designed 0.2-mm-wide nozzle with triangular cavities exhibits a better particle removal rate than previous nozzles, in spite of the flow rate being approximately half of the previous one. In addition, we estimated adherence and removal forces. The dominant removal force is not drag or lift force, but the pressure gradient induced by the impingement of a strongly turbulent air flow. The predicted relation between particle size and particle removal rate from the estimation agrees with the experimental results.

View full abstract

   In a conceptual design study on a commercial Fast Breeder Reactor, a large-diameter high-chrome steel piping was introduced to shorten the length of the piping. Ordinarily, an electromagnetic flowmeter (EMF) is applied to measure the flow rate of liquid metal such as sodium. However, because the EMF is not well suited to magnetic material, such as high-chrome steel, an ultrasonic flowmeter is being developed to measure the flow rate of sodium. An ultrasonic transit-time method is applied to flow rate measurement. Water-flow tests were carried out using a 1/4 scale model in order to evaluate the effect of the number of ultrasonic propagation paths on applicability to measurement and development requirements. As a result, it was confirmed that linearity of flow rate and measurement response time requirements were satisfied with 2- and 4-paths. Also, it was found that flow rate measured by the ultrasonic flowmeter in the 4-path did not depend on the installation position of the transducer in a piping system with upstream pipe from 3.0 to 3.6 times the piping inner diameter. From the above results, it was verified that the ultrasonic flowmeter is applicable to a commercial FBR by adopting the multi-path system.

View full abstract