In our previous research, coated-cemented-carbide tools were found to be so effective for ultra-precision cutting of titanium metals and stainless steels. The surface roughness formed by ultra-precision cutting of titanium alloys was below 200 nm(Rz) when cutting lengths up to 2,000 m. However it is not adequate for producing efficiently ultra-precision components. It is considered that tool wear is caused by the cutting temperature rise due to the contact of tool to workpiece at high cutting speeds. In order to improve the surface roughness and tool life, in the research, the effect of low cutting speeds on ultra-precision cutting of β type titanium alloy with coated-cemented-carbide tool is examined. Using the extremely low cutting speed, below 1 m/min, the surface roughness at the depth of cut of 5 μm attains 84 nm(Rz) and keeps below 100 nm(Rz) until cutting length of 4,000 m and below 200 nm(Rz) until cutting length of 10,000 m. At the high depth of cut of 500 μm, furthermore, the surface roughness becomes about 100 nm(Rz) at cutting length of 212 m.

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This paper clarifies the mechanism of the electromagnetic force applied to the wire electrode in wire-EDM. The distribution of the magnetic flux density caused by the steady current was analyzed using finite element method (FEM) to calculate the electromagnetic force. The electromagnetic force theoretically obtained was used for analysis of the wire vibration under two kinds of current waveforms: single long current pulse and consecutive short current pulses. From the comparison of wire vibrations obtained from the experiment and analysis, it was found that the electromagnetic force is caused by both DC and AC components of the discharge current. When the workpiece is ferromagnetic, the electromagnetic force caused by DC component of the discharge current is dominant, and it is an attractive force. When the workpiece is paramagnetic, the electromagnetic force caused by DC component of the discharge current is insignificant compared with the force caused by AC components due to electromagnetic induction.

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By using modulated laser diode, standing wave is excited on the micro-disk, and guide line of the selection of material for photothermal effect is shown from the properties of the disk material. Amplitude increases with decreasing the thickness of micro-disk. Amplitude increases with ratio of the coefficient of thermal expansion and the thermal conductivity. Moreover, amplitude increases with laser output. It is obtained that stainless steel is most suitable material for photothermal-effect from the properties of the disk material.
Traveling wave of mode shape No.3 is excited on a micro-disk by using two modulated laser diodes. Amplitude and direction of the traveling wave are controlled by changing duty ratio of a laser and phase difference. By controlling the phase of the modulated laser diode, traveling wave generated on the micro-disk is controlled to the direction of clockwise or counter-clockwise. By controlling the duty ratio of the modulated laser diode similar to the PWM control, amplitude of standing wave and traveling wave are controlled. The highest peak-to-peak amplitude of standing wave is generated at the duty ratio of 75% and higest peak-to-peak amplitude of traveling wave is generated at the duty ratio of 70%.

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Etching of NiTi shape memory alloy (SMA) using mask fabricated by laser irradiation is studied in this paper. Thermal oxidized at 200-700°C in air atmosphere and unheated SMAs are electrochemically etched in 1 mol/l LiCl-ethanol electrolyte. Both unheated and heated at 200°C samples are etched and other samples (heated over 300°C) are not etched. Over 300°C heating, oxidized film was formed on SMA surface and the film has etching resistance property. To fabricate oxidized film, SMA surface was irradiated by focused Ar ion laser beam. Laser beam irradiated point is observed with optical microscope, AFM and SEM. No visible changes are found after 200mW laser beam irradiation. When laser power is 300mW, pale color discoloration area is observed. Uplift is found after 500mW X over 1s, 600mW X 0.1s or over 700mW irradiation. Laser beam irradiated surfaces are etched and etching shapes are observed. Micro pillars are found when the laser beam irradiation conditions are 300mW X over 0.7s or 400mW. When laser power is over 500mW defects are fabricated on the pillar. Fabricated pillar diameter is 2.8-15.6μm and height is 7.5-8.5μm after 5min etching. Etching after 100μm/s laser beam scanning make 5.7-7.0μm width and 9.1-10.2μm height wall shape.

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This paper describes a die-sinking EDM simulation which can simulate the wear of tool electrode with sharp edges and the distribution of debris particles concentration in the machining gap. This simulation is based on the discharge location searching algorithm to reproduce the gap phenomena caused by every pulse discharge. The algorithm is a simple repetition of the routine which is composed of: 1) determining the next discharge location, 2) removing the tool electrode and work piece electrodes, 3) distributing debris particles, and 4) feeding the tool electrode. This algorithm was modified to simulate the removal of surfaces with large inclination, lateral surfaces and edge portions of the tool electrode. Moreover, a method to calculate the debris particles concentration in the gap extended three dimensionally was developed. Thus, the wear of tool electrode with sharp edges was simulated combining the discharge location searching algorithm with the 3D calculation of debris concentration. Simulation results agreed with experimental results especially in the case of using brass as the tool electrode material with which deposition of carbon on the tool electrode is negligibly small.

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A new finishing process for metal molds by large-area electron beam irradiation (EB polishing) was proposed and the fundamental effects of EB irradiation conditions on surface finishing, the surface modification effect and others were investigated in the previous report. As a result, the surface roughness on the whole surface within 60mm in diameter could be reduced from 6μmRz to less than 1μmRz in just a few minutes under a proper condition, and the surface roughness could be well improved even if the surface tilting angle is close to 90 degrees. In addition, the corrosion resistance of metal mold surface could be improved. However, small craters sometimes were generated on the EB irradiated surface, which might deteriorate the quality of products. In this study, the relationship between crater generation and workpiece material was examined. Experimental results made it clear that the generation of crater and its disappearance were repeated on the surface with EB irradiation, and the generation of crater greatly depends on the nonmetallic additives in base material, particularly on MnS. Moreover, the impurity of workpiece material also has a significant influence on the crater generation.

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Molecular self-assembling is one of the important technologies for fabrication of nano-mechanisms in the bottom-up techniques. Among many kinds of biomolecular, DNA has several advantages such as creativity of arbitrary base sequence by DNA synthesizer, sub-nm self-positioning resolution in hybridization, and well-developed cut-and-paste technique, which is attractive for nano-mechanism fabrication. This report describes the design and fabrication of DNA-based nanostructures (“DNA glasses”, “DNA serial rings”, and “DNA chains”) using DNA ring-protein complex. An experiment has been performed to form the DNA ring using two types of DNA (“vector DNA”) obtained by cutting plasmid with restriction enzyme and biotin conjugated DNA (“insert DNA”). After ligation and introduction of streptavidin modified gold nanoparticle, DNA-based nanostructures have been obtained. And then, DNA-based nanostructures were observed by an Atomic Force Microscope (AFM). By a function of the AFM micrograph processing software, a cross sectional analysis was performed. As a result, the diameter of the DNA rings was from 21 to 24 nm, which was almost the same as the theoretical value (25 nm). Hence DNA-based nanostructures were confirmed to be fabricated in the designed construction.

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The purpose of the study is to propose a model for the forearm torsion operations, such as screw driving and knob turning. In this paper, the rotational ranges of the object twisted by the upper limb are measured at various working positions during the forearm torsion operations. As a result, it is shown that the rotational ranges of the object vary depending on the working positions. A degree of coincidence is defined among the direction vectors of the segments in the link model representing the upper limb and the object. Formulas are derived to estimate the rotational ranges of the objects based on the degree of coincidence among the directions vectors.

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We present theoretical and experimental analyses of an optical attitude sensing system for an MRI-compatible surgical assist manipulator using a spherical ultrasonic motor. In the system, a laser light passes through an optical fiber to a flat mirror of a spherical rotor; the reflection from the mirror is caught by optical fibers. The observed light intensity is converted to attitude information by a neural network, and the rotation of the spherical rotor is detected. The system uses optical fibers and allows the spherical rotor to be miniaturized and inexpensive. In this report, we developed the optical attitude sensing system and tested the drive of spherical ultrasonic motor with the sensing system. As the result, the attitude sensing resolution was less than 0.5°. The sensing system has indicated the feasibility for the control of the manipulator.

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Magnetically compatible robots are required as haptic interfaces for neuroscience studies. The purpose of this paper is to develop an MR compatible robot using ultrasonic motor, which is able to work within an MRI/fMRI scanner and to acquire MRI images continuously during finger motions. In addition, the force field control method of ultrasonic motor is discussed. The characteristic of voltage phase and motor torque is investigated experimentally, and these results are used for the force field control of ultrasonic motors. The position dependent force fields and velocity dependent force fields are evaluated with a force sensor. Also, MR compatibility is verified experimentally. Finally, some brain activities are investigated with fMRI during finger movements.

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The authors have proposed a driving method of a piezoelectric actuator by using current pulses for the high resolution. It was applied to the driving method of Extension device of AZARASHI (Seal) Mechanism. A device with 1 degree of freedom was designed for the improvement of the resonant frequency and resolution by using the finite element method. A piezoelectric actuator was used for a clamp of the controlled Friction device to improve the response time. The device runs along a double-V guide for the high motion accuracy. In Coarse mode, Extension device repeats the extension and contraction with its full stroke. Then, Friction device for a constant friction is positioned during fixing the controlled Friction device in Fine mode. In the case of the reference position of 100 μm, the settling time within 5 nm was 376 ms.

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On a two-dimensional jumping behavior by a multi-link mechanism, a mechanism that imitated a animal's leg and a mechanism of conventional robot were compared analytically. Each joint of a conventional robot is independently controlled. On the other hand, because animal's leg has bi-articular muscle, the adjoining joints are not independent. The animal's leg mechanism was imitated by using the closed link mechanism with the rod which connects two joints. For the mechanism which imitated animal's leg and the mechanism of conventional robot, under the ideal condition, each joint torque for stabilized jump ware deduced. On the conventional robot, it is necessary to detect the center of gravity, and to be feedback. By contrast, in the mechanism which imitated the animal's leg, it does not need to feedback the position of center of gravity. Furthermore, four-legged jump robot with the mechanism which imitated animal's leg was produced, and the effectiveness of that mechanism was confirmed by an experiment.

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