We present a rapid process for producing flat and smooth surfaces. In this technical note, a fabrication result of a carbon mirror is shown. Electrolytic in-process dressing (ELID) grinding with a metal bonded abrasive wheel, then a metal-resin bonded abrasive wheel, followed by a conductive rubber bonded abrasive wheel, and finally magnetorheological finishing (MRF) were performed as the first, second, third, and final steps, respectively in this process. Flatness over the whole surface was improved by performing the first and second steps. After the third step, peak to valley (PV) and root mean square (rms) values in an area of 0.72 x 0.54 mm² on the surface were improved. These values were further improved after the final step, and a PV value of 10 nm and an rms value of 1 nm were obtained. Form errors and small surface irregularities such as surface waviness and micro roughness were efficiently reduced by performing ELID grinding using the above three kinds of abrasive wheels because of the high removal rate of ELID grinding, and residual small irregularities were reduced by short time MRF. This process makes it possible to produce flat and smooth surfaces in several hours.

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The wear resistance of coating films on hob teeth is investigated through the simulated hobbing tests with a flytool. The coating films on hob teeth are titanium family ceramics such as TiN, TiCN, TiSiN and TiAlN and aluminum chromium family ceramics such as AlCrN and AlCrSiN. The wear of coated tools is shown about film thickness, film materials, ingredient ratio in a film component and the oxidization of coating films. The oxidization is clarified from a result of the influence on the crater wear progress through wear cutting tests in atmosphere of nitrogen gas or oxygen gas. The oxidization of TiAlN coating films produces oxide products on the tool rake face, and this oxidation relates to the amount of crater wear. The increase of aluminum concentration in the TiAlN film improves the crater wear resistance in air atmosphere, while it has a reverse effect in nitrogen gases. The AlCrSiN film has effective wear resistance against the abrasive wear and/or oxidization wear. The oxidation film formed on the AlCrSiN film is very firm and this suppresses the oxidation wear on the rake face and works against the abrasive wear advantageously.

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Principal component analysis (PCA) coupled with Taguchi methods are employed in the study for developing multiple quality characteristics optimization of pulsed plasma arc welding SS400 steel pipe with foamed aluminum liner (SPFAL). The quality characteristics investigated are the micro-hardness, the compression strength, and the bending strength of the weldments. Eight control factors selected are the tip aperture (Factor A), plasma base current (Factor B), plasma pulse current (Factor C), duty cycle (Factor D), pulse frequency (Factor E), shielding gas (Factor F), plasma gas (Factor G), and welding velocity (Factor H), respectively. It is shown by the experimental results that the optimal parameter combination of the pulsed plasma arc welding process is A1 (tip aperture: Ø1.5mm), B3 (plasma base current: 30A), C3 (plasma pulse current: 100A), D2 (duty cycle: 50%), E3 (pulse frequency: 300Hz), F2 (shielding gas: 14L/min), G3 (plasma gas: 0.4L/min), and H2 (welding velocity: 4RPM). Moreover, it is ascertained from the analysis of variance (ANOVA) results that plasma base current (B), plasma pulse current (C), duty cycle (D), and welding velocity (H) are the most important control factors in the process design, and thus strict control must be applied to them. They account for 75.02% of the total variance. The experimental results likewise show that the best process design could indeed enhance the multiple quality characteristics of the pulsed plasma arc welded SPFAL as 3020kgf of the bending strength, 13650kgf of the compression strength, and 180.4Hv of the hardness, respectively.

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This paper develops a newly bicycle concept named smart bicycle (SBIC) with automatic transmission and energy recuperating ability. The SBIC operation is based on a hydrostatic transmission (HST). Several HST designs have been proposed. Moreover, a use of energy converting and storing devices is an optional design for the SBIC to recovery energy during the deceleration or going downhill process, and to support this energy to the hydraulic system during the acceleration or going uphill process. The working efficiency of the bicycle is then increased and could become competitive with the roller-chain technology. Simulations have been carried out to evaluate the working performances of the proposed SBIC concepts.

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In this study, a positioning stage is considered, which is actuated by four pneumatic cylinders and vertically supported by four coil-type spring isolators. Previously, we realized the base plate jerk feedback (BPJFB) to be analogues to a Master-Slave system which can synchronize the motion of the stage as a Slave to the motion of the base plate as a Master. However, in the case of real positioning, the stage had slightly self oscillation with higher frequency due to the higher gains set to the outer feedback loop controller besides its oscillation due to the natural vibration of the base plate. The self oscillation of stage was misunderstood to be the natural vibration of base plate due to the reaction force. However, according to the experimental results, the BPJFB scheme was able to control both of the mentioned vibrations. Suppression of the self vibration of stage is an interesting phenomenon, which should be experimentally investigated. Therefore, the current study focuses on the suppression of the self vibration of stage by using the BPJFB scheme. The experimental results show that besides operating as a Master-Slave synchronizing system, the PBJFB scheme is able to increase the damping ratio and stiffness of stage against its self vibration. This newly recognized phenomenon contributes to further increase the proportional gain of the outer feedback loop controller. As a result, the positioning speed and stability can be improved.

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A wearable Knee Assistive Instrument for the walk rehabilitation was newly developed. Especially, this system aimed at supporting the rehabilitation for the post-TKA (Total Knee Arthroplasty) which is a popular surgery for aging people. This system consisted of an assisting mechanism for the knee joint, a hip joint support system and a foot pressure sensor system. The driving system of this robot consisted of a CPU board which generated the walking pattern, a Li-ion battery, DC motors with motor drivers, contact sensors to detect the state of foot and potentiometers to detect the hip joint angle. The control method was proposed to reproduce complex motion of knee joint as much as possible, and to increase hip or knee flexion angle. Especially, this method used the timing that heel left from the floor. This method included that the lower limb was raised to prevent a subject's fall. Also, the prototype of knee assisting system was tested. It was confirmed that the assisting system is useful.

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As a mechanical system has larger number of degree-of freedom (DOF) of motion in order to generate diverse behavior, it becomes more difficult to design the control scheme for its motion to achieve a specific function required for the system. This paper proposes a novel design methodology for the control scheme in order to deal with the above-mentioned difficulty. The design methodology proposed is inspired from the concept of emergence observed in living organisms, that is, diverse behavior is emerged to an ultra multi-DOF dynamic system only with a single set of local rules using local information between neighboring subsystems. This study simplifies the ultra multi-DOF system as an 11×11 lattice mass system, neighboring masses are connected with a linear actuator, and aims to prevent a target mass point (control subsystem) from moving even if any external forces are input to the system, which we call this function “displacement controllability.” Hence the P/D gains of the actuators are turned ON/OFF by the proposed local rule for displacement controllability. As a result of computation, the displacement controllability was successfully emerged to the mass system under the various environments, i.e., diverse external force inputs. That means, the diverse behavior dealing with various environments was generated to the system only using the single local rule. Consequently, the effectiveness of the proposed behavior design methodology for an ultra-multi-DOF system was confirmed.

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This paper deals with thin-film polyimide membrane actuators. The membranes were fabricated by deep-RIE using the Bosch process for etching a silicon substrate up to the polyamide layer, since we found that the polyimide layer was scarcely etched in this process. Membranes that were 5 mm in diameter and 2-10 µm thick were fabricated. The characteristics of membrane deflection were experimentally and analytically investigated by applying static pressure. The membranes could produce displacement on the order of a hundred micrometers in an experiment. We chose thermal expansion to actuate the membranes as actuators. Applying electricity to an aluminum layer deposited on the membrane deflected the membrane due to the thermal expansion of the aluminum layer. The experiments demonstrated that membranes 3-10 µm thick produced displacements at the membrane centers in a range from 10-20 µm by applying 1 V and the actuators worked periodically by turning the supply of electricity on and off.

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This paper focuses on the mathematical modeling for 5-axis milling with a filleted end mill. Several coordinate systems are introduced to describe the relationship between a cutter orientation and a machined surface. Then, a cutting point on a cutting edge is geometrically formulated as an integrated form of some expressions. The fundamental simulations based on the modeling were implemented to investigate the characteristics of path-interval and feed-interval scallops on a machined surface; moreover, path interval determination is proposed for suitable estimation in filleted end milling. As a result, it was found that the proposed approach could provide the characteristics of microscopic topography in detail.

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Cycloid drive is used widely in many industrial areas for both power transmission and precision transmission. In this paper a novel cycloid drive is proposed and its meshing characteristics are analyzed. The conjugated gear pair of this novel cycloid drive is composed by an external cycloid-arc gear and an internal ring gear. Firstly, the idea of this novel cycloid drive is described and the tooth profile equation of the external cycloid-arc gear is presented. Secondly, based on coordinate transformation and gear geometry theory, the meshing equation for this novel cycloid drive is established, the equation of the conjugated tooth profile and the formula of induced normal curvature are also derived. Thirdly, the meshing characteristics are analyzed based on a numerical example: the drawing of the conjugated tooth pair is presented and compared with the conventional cycloid drive and the double-enveloping cycloid drive; the contact lines between one tooth pair at different meshing positions are illustrated. Finally, the induced normal curvature is calculated and compared with that of the conventional cycloid drive and the double-enveloping cycloid drive, which shows good characteristic of this novel cycloid drive.

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