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Interior permanent magnet synchronous motors are becoming increasingly popular as traction motors in environmentally friendly vehicles. These motors, which offer a wide range of design options, require time-consuming finite-element analysis to verify their performance, thereby extending design times. To address this problem, in this article, we propose a deep learning model that can accurately predict the iron loss characteristics of different rotor topologies under various speed and current conditions, resulting in an automatic design system for the internal permanent magnet synchronous motor rotor core. Using this system, the computation time for efficiency maps is reduced to less than 1/3000 of the time required for finite-element analysis. The system also shows efficiency optimization results similar to the best results of previous research while reducing the computational time for optimization by one or two orders of magnitude.

Majorana bound states can occur in a topological Josephson junction (JJ) array in the presence of a fractal vortex with 2$\pi$-phase winding. The braiding operation was theoretically demonstrated using current pulses, compatible with the single flux quantum (SFQ) technology. Herein, we designed an SFQ logic circuit for braiding operations of a topological JJ array using single flux quanta. Braiding operations could be realized using a bipolar current pulse generator controlled by an SFQ logic circuit.

Interior permanent magnet synchronous motors (IPMSMs) are currently widely used for traction applications. However, the torque ripple in these motors needs to be reduced because it causes vibration and acoustic noise. Accordingly, this study first determines the guidelines for reducing the torque ripple of multilayer IPMSMs and then proposes a double-layer IPMSM with holes drilled in the rotor core. The torque ripple reduction for the proposed rotor structure is examined using 2-D finite element analysis and experiments with prototypes. The analytical results show that, under maximum torque-per-ampere control, the torque ripple using the proposed model was suppressed by 54.8% compared with the reference model while limiting the average torque reduction to 3.6%. Moreover, multiobjective optimization based on the guidelines is performed. With the proposed structure, the torque characteristics at high and low currents are highly correlated, and a similar torque ripple reduction effect is obtained even at low current, which is frequently used in traction motors for automotive applications. Finally, optimization is performed for an IPMSM with other topologies, resulting in verification of the generalizability of the proposed method.

Objective: To identify the risks of myocarditis or pericarditis after vaccination with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mRNA vaccines in Japan. Methods: We conducted an observed-to-expected analysis (OE analysis) of spontaneous reports of suspected adverse events from pharmaceutical companies, calculating rate ratios with myocarditis and pericarditis after the vaccination of the mRNA vaccines Comirnaty (BNT162b2) and Spikevax (mRNA-1273) and expected rate of myocarditis and pericarditis in the population before the COVID-19 pandemic. These reports dated from 17/2/2021 to 14/11/2021 and from 22/5/2021 to 14/11/2021 for Comirnaty and Spikevax, respectively. The observed-to-expected ratios (OE ratios) for each vaccine were estimated by age groups and sex. Results: We identified 281 and 195 cases of myocarditis or pericarditis for Comirnaty and Spikevax, respectively, which were administrated 163,059,502 and 31,768,352 doses for Comirnaty and Spikevax until the 14th of November 2021, respectively. The OE ratios were statistically significantly higher in adolescent and young adult males in their age of teens and twenties after the second dose in a two-dose series [Comirnaty in teens male: 6.15 (95% CI, 2.26–21.98), Comirnaty in twenties male: 2.86 (95% CI, 1.13–8.38), Spikevax in teens male: 41.59 (95% CI, 5.64–43,281.94), Spikevax in twenties male: 16.84 (95%CI, 6.77–57.49)]. Conclusions: Risks of myocarditis and pericarditis following SARS-CoV-2 mRNA vaccines in Japan seems to be significantly elevated for adolescent and young adult males.

The optimal design of interior permanent magnet synchronous motors requires a long time because finite element analysis (FEA) is performed repeatedly. To solve this problem, many researchers have used artificial intelligence to construct a prediction model that can replace FEA. However, because the training data are generated by FEA, it takes a very long time to obtain a sufficient amount of data, making it impossible to train a large-scale prediction model. Here, we propose a method for generating a large amount of data from a small number of FEA results using machine learning. An automatic design system with a deep generative model and a convolutional neural network is then constructed. With its sufficient data, the proposed system can handle three topologies and three motor parameters in a wide range of current vector regions. The proposed system was applied to multi-objective optimization design, with the optimization completed in 13–15 seconds.

Background: Sarcopenia, a syndrome characterized by the loss of skeletal muscle mass, has attracted attention in the field of oncology, as it reflects poor nutritional status. The present study aimed to determine the risk factors for postoperative inguinal hernia (PIH) development after robot-assisted laparoscopic radical prostatectomy (RARP) for prostate cancer, and discuss whether sarcopenia could be used as a sensitive predictor of PIH. Methods: We reviewed the medical records of 147 patients who underwent RARP at our institution. The psoas muscle volume (PMV), as an indicator of sarcopenia, was quantified from computed tomography images using a 3-dimensional image analysis system. Multivariate cox regression analyses were performed to identify independent predictors of PIH, including pre- and peri-operative factors. Results: The mean PMV was 393 cm3, and the correlation coefficient between PMV and body mass index was 0.37 (p< 0.01). The PIH-free rate at 2 years postoperatively was 78.2% among all patients. The multivariate analysis revealed that a PMV < 350 cm3was a significant risk factor for PIH (p= 0.03; hazard ratio 2.19). Body mass index, age, prostate volume, lymph node dissection, nerve sparing, rectus muscle thickness, and console time were not related to PIH development. The PIH-free rate at 2 years postoperatively was 83.4% and 68.9% in patients with a PMV ≥ 350 cm3and < 350 cm3, respectively (p< 0.05). Conclusions: PIH occurred significantly more frequently in patients with a PMV < 350 cm3than in patients with a PMV ≥ 350 cm3, and a low PMV was an independent risk factor for PIH. Thus, urologists should pay attention to the cumulative incidence of IH after RARP, especially in patients with a PMV < 350 cm3.

This paper presents a compact XYZmicro-stage driven by an impact driving mechanism. A moving body is translationally actuated along the X-, Y-, and Z-axes in millimeter-scale range and with nanometer-scale resolution. Cr–N thin-film strain sensors are integrated into the micro-stage for closed-loop positioning. Closed-loop control is also carried out. The motion errors in six degrees of freedom are also investigated for this micro-stage. It is clarified by analysis of finite element method that rotational motion errors around the driving axis are caused by torques due to tensions from the elastic hinges of micro-stage. The mechanical structure of XYZmicro-stage to cancel out the torque generated is proposed and the second prototype is fabricated. Although the rotational motion error is successfully suppressed in the second prototype, a rotational motion error of more than 0.1° remains due to remaining torque and assembly error of the elastic hinges. Then, in order to reduce the rotational motion error, the prototype is designed in which the location of elastic hinges is single-layered. By designing a mechanical structure in which torque is suppressed, all rotational motion errors are successfully reduced to less than 0.05° in the prototype with single-layer hinges.

This paper proposes a new optical angle measurement method based on second harmonic generation with a mode-locked femtosecond laser source by taking use of the unique characteristic of high peak power and high-intensity electric field of the femtosecond laser pulses. The angle is measured from the second harmonic wave intensity, which is a function of the angle between the laser beam axis and the optic axis of a nonlinear crystal attached to the target of interest. It is found that the beta barium borate (BBO) crystal is suitable as the nonlinear crystal for this purpose through theoretical simulation. As the first step of research, an experimental demonstration is also carried out in such a way that a change of the second harmonic wave intensity due to the angular displacement of BBO crystal is measured to verify the feasibility of the proposed principle of the angle measurement method.

Periodontal disease is the leading cause of tooth loss, and an association between periodontal disease and non-oral systemic diseases has been shown. Formation of biofilm by periodontal pathogens such as Fusobacterium nucleatum, Porphyromonas gingivalis, and Streptococcus mutansand their resistance to antimicrobial agents are at the root of persistent and chronic bacterial infections.

The feasible resolution of angular displacement measurement by an optical angle sensor based on laser autocollimation is investigated. Improving the sensor sensitivity while maintaining the noise level of the sensor signal as low as possible is necessary to achieve high-resolution angular displacement measurement. In this paper, the contribution of each component, such as a photodiode, a trans-impedance amplifier, and an analog-to-digital converter in the optical angle sensor, to the noise level of the sensor signal is first estimated on the basis of theoretical equations. The feasible sensitivity of the optical angle sensor is also estimated in numerical calculations. The sensitivity of a photodiode element at the edge of its photosensitive area is evaluated in experiments to realize the estimation of the angle sensor sensitivity. Experimental results are applied to the numerical calculations. The influences of the measurement laser beam diameter, the spot diameter of the focused laser beam on the photosensitive area, and the focal length of the collimator objective of the optical angle sensor are also considered in the numerical calculations. Finally, a prototype optical setup is developed. Experiments are performed to demonstrate that a compact optical angle sensor based on laser autocollimation with a collimator objective having a focal length shorter than 100 mm can achieve a resolution beyond 0.001 arc-second with a bandwidth of 1 kHz. This resolution is better than those achieved by commercial autocollimators employing an image sensor or a position-sensitive detector. The industrial contribution of this paper lies in the detailed breakdown of noise components in the readout signal of an angle sensor in a practical condition and the systematic estimation of its feasible resolution as well as its sensitivity.

In this paper, an attempt is made to integrate a compact strain gauge-type displacement sensor referred to as the Cr–N thin-film displacement sensor into the XYmicro-stage designed in a small size of 25 mm (X) × 25 mm (Y) × 6.5 mm (Z) to achieve closed-loop nano-positioning of the stage. In the XYmicro-stage, which has been developed in the previous study by the authors, Cr–N strain gauges for the Cr–N thin-film displacement sensors are directly fabricated on elastic hinges integrated into the stage structure so that the elastic hinges can be employed as sensors for stage positioning as well as guides for a stage table. In this paper, two types of the Cr–N thin-film displacement sensor having different layouts of the strain gauges, line patterns and land patterns are designed and fabricated. Computer simulation based on the finite element method is also carried out to evaluate the robustness of sensors against the external disturbances from electrical wires soldered onto a sensor surface. After some basic experiments, each of the developed Cr–N thin-film displacement sensors is integrated into the XYmicro-stage, and its feasibility is evaluated in experiments.

A new concept of reading head for a linear encoder, in which graduations on a scale grating are read by using a micro thermal sensor composed of a thin film resistor, is proposed to realize a compact encoder system. In the proposed reading head, measurement of the in-plane relative displacement between the micro thermal sensor and the scale grating will be carried out in such a way that the graduations on a scale grating are read by the micro thermal sensor through the change in the heat flow between the sensor and the scale grating surface. In this paper, as the first step of research, theoretical calculations based on the theory of heat flow between the sensor and scale interface are carried out. In addition, basic experiments are carried out to search for the possibility of realizing the proposed concept of the reading head based on the micro thermal sensor.

This paper presents the reduction in cross-talk errors in the angular outputs existing in the previously designed six-degree-of-freedom (DOF) surface encoder for nanopositioning and nanometrology. The six-DOF surface encoder is composed of a planar scale grating and an optical sensor head with a reference grating, a displacement assembly and an angle assembly. The diffracted beams from both the scale and the reference gratings are received by the displacement assembly for measurement of the primary XYZtranslational motions. The angle assembly only receives the diffracted beams from the scale grating for measurement of the secondary θXθYθZangular motions. In this paper, at first, the cross-talk errors in the angular measurement results of the previous surface encoder are identified to be caused by the diffracted beams from the reference grating leaking into the angle assembly due to the imperfection of the polarization components of the sensor head. An improved design of the sensor head is then carried out to reduce the cross-talk errors by changing the position of the angle assembly in the sensor head. The sensor head is further optimized by replacing the beam splitter located in front of the angle assembly from a cube type to a plate type. Experimental results have demonstrated that the cross-talk errors were reduced from 3.2 arc-seconds to 0.02 arc-second.

This paper proposes a new method for measurement of the roll error motion of a slide table in a precision linear slide. The proposed method utilizes a pair of clinometers in the production process of a precision linear slide, where the roll error motion measurement will be carried out repeatedly to confirm whether the surface form errors of slide guideways in the linear slide are sufficiently corrected by hand scraping process. In the proposed method, one of the clinometers is mounted on the slide table, while the other is placed on a vibration isolation table, on which the precision linear slide is mounted, so that influences of external disturbances can be cancelled. An experimental setup is built on a vibration isolation table, and some experiments are carried out to verify the feasibility of the proposed method.

A sensitive analytical method was developed for the simultaneous detection of 11 chiral pharmaceuticals and their hepatic metabolites by liquid chromatography-tandem mass spectrometry (LC-MS/MS) using an ovomucoid chiral column. After optimization of the LC conditions, all pharmaceuticals examined were enantio-separated with Rsof >0.82 in LC-MS/MS analysis. The limit of detections of all pharmaceuticals by MS/MS detection ranged from 1.2 to 92.3 nM, which is approximately 1000–25000 times lower than those obtained by UV detection. From hepatic metabolite analyses in P450-expressing cells, metabolites of three pharmaceuticals were detected and enantio-separated. By using the proposed method, changes in the optical isomer ratio of the hepatic metabolites chlorpheniramine and verapamil caused by differential cytochrome P450 enzyme expression for each isomer, could be successfully traced.

The tool–workpiece interactions when a single-point diamond cutting tool with specific tool edge geometry is made to contact with a copper workpiece are evaluated by the molecular dynamics simulations under different temperatures, boundary conditions and model sizes for ultra-precision microcutting and in-process surface form measurement based on a force sensor–integrated fast tool servo. It is confirmed that the proposed multi-relaxation time method is effective to stabilize the workpiece molecular dynamics model over a wide temperature range up to the room temperature under which a practical microcutting and on-machine surface form metrology process are conducted. The boundary condition and model size of the molecular dynamics model are then optimized to make reliable and cost-effective simulations for evaluation of the elastic–plastic transition contact depth and the corresponding contact force when a diamond tool with a practical edge sharpness of up to 30 nm is employed for microcutting and on-machine surface form metrology.

This paper presents a design and testing of a micro-thermal sensor probe for realizing the proposed concept of non-contact surface defect detection, in which a change in heat flow across the gap between the tip of the micro-thermal sensor probe and a target surface is utilized to recognize the existences of surface defects. In the proposed concept of surface defect detection, the probe tip, where the micro-thermal sensor is embedded, is required to be placed as close as possible to the target surface for highly sensitive surface defect detection. For the purpose, an optical tilt detection assembly based on the laser autocollimation is designed to detect relative tilt of the micro-thermal sensor with respect to a target surface. A sensor probe assembly, in which the fabricated micro-thermal sensor is embedded to the tip of a hollow-shaped piezoelectric actuator by using a homemade sensor mount, is also designed in such a way that the sensor element will face to a target surface. A prototype micro-thermal sensor probe is constructed by integrating the optical tilt detection assembly and the sensor probe assembly, and some experiments have been carried out to verify the basic performances of the prototype micro-thermal sensor probe.

This paper presents an uncertainty analysis of a six-degree-of-freedom surface encoder, which is designed to measure multi-degree-of-freedom motion of a planar motion stage with a single laser beam. Since the surface encoder is composed of an optical sensor head and a two-axis scale grating, optical misalignments in the sensor head and form errors of the scale grating will affect the measurement uncertainty. In this paper, aiming to achieve further accurate measurement of translational displacement, an uncertainty budget table is built for the X-directional translational displacement measurement, while considering the above mentioned uncertainty sources.

Prior research on the perception of facial expressions suggests that East Asians are more likely than North Americans to incorporate the expressions of background figures into their judgment of a central figure’s emotion (Masuda et al. in J Pers Soc Psychol 94:365–381, 2008b). However, little research has examined this issue in the context of developmental science, especially during joint sessions where parents engage in a task in front of their 7–8-year-old children. In this study, 22 Canadian and 20 Japanese child-parent dyads participated in an emotion judgment task, and were asked to judge a central figure’s emotion and explain their reasoning. The results indicated that while early elementary school children did not show culturally dominant reasoning styles, parents displayed culturally dominant modes of attention, serving as models for their children.

This paper presents a design study of an optical three-axis angle sensor for measurement of angular error motions of long-stroke precision linear stages. The three-axis angle sensor, which is based on a laser autocollimation method, can detect angular motions about the XYZ-axes simultaneously by using zeroth-and first-order diffraction beams from a diffraction grating mounted on a measuring target as a reflector. In this paper, an optical sensor head is designed in such a way that the three-axis angle sensor shares a diffraction grating with an optical sensor head of a linear encoder, which is already installed in a stage system. The optical sensor head of the three-axis angle sensor is designed in a size of smaller than 50 mm × 30 mm × 30 mm so that the sensor head can be compatible with the linear encoder. Details of the optical configuration designed for the sensor head, and some results of experiments are reported.

In this study, a long stroke atomic force microscope (LS-AFM) has been developed for the measurement of the micro-optics which have micrometric amplitude surface structures. An electrochemically polished tungsten wire is used as the AFM probe tip. Since the effective length of the tungsten probe is more than 100 μm, the probe tip can access valley part without the interference between the steep slope and the sidewall of the probe tip. By using the long stroke PZT Z scanner whose long stroke of 70 μm and a resolution of 1 nm, micrometric amplitude of the optical elements can be measured. A linear encoder is employed to measure the displacement of Z scanner in Z direction. A well-detected result of a prism sheet film profile has been obtained by the LS-AFM and its tapping mode.

Eleven biosurfactant-producing strains were newly isolated from environmental samples using a drop-collapse assay and thin-layer chromatography (TLC). According to the TLC analysis, the separation patterns of the glycolipid spots of nine dominant strains corresponded to that of the sophorolipids produced by a Starmerella bombicolatype strain. The retention factor values of the spot patterns of two strains were less than those of the others. Two representative major products were purified, and their molecular structures were determined. The major products were identified as diacetylated lactonic and acidic sophorolipids. The fatty acid moieties of both compounds were estimated to be 17-hydroxymethyl hexadecenoic acid. The amounts of glycolipids ranged from 5.0 to 22.9 g/L after 4 d of cultivation. According to a phylogenetic analysis, the strains were identified as Starmerella bombicolaand Candida floricola.

Recent rodent studies have shown that nanoparticles are distributed to breast milk, and more-detailed safety information regarding nanoparticle consumption by lactating mothers is required. Here, we used mice to investigate the safety of nanoparticle use during lactation. When Ag and Au nanoparticles were intravenously administered to lactating mice, the nanoparticles were distributed to breast milk without producing apparent damage to the mammary gland, and the amount of Ag nanoparticles distributed to breast milk increased with decreasing particle size. Orally administered Ag nanoparticles were also distributed to breast milk and subsequently to the brains of breast-fed pups. Ten-nanometer Ag nanoparticles were retained longer in the pups’ brains than in their livers and lungs. Nevertheless, no significant behavioral changes were observed in offspring breast-fed by dams that had received orally administered 10 nm Ag nanoparticles. These data provide basic information for evaluating the safety of nanoparticle use during lactation.

The charge detector (CHD) of the Calorimetric Electron Telescope (CALET) on board the International Space Station (ISS) has a huge geometric factor for detecting MeV electrons and is sensitive to relativistic electron precipitation (REP) events. During the first 4 months, CALET CHD observed REP events mainly at the dusk to midnight sector near the plasmapause, where the trapped radiation belt electrons can be efficiently scattered by electromagnetic ion cyclotron (EMIC) waves. Here we show that interesting 5–20 s periodicity regularly exists during the REP events at ISS, which is useful to diagnose the wave‐particle interactions associated with the nonlinear wave growth of EMIC‐triggered emissions. CALET on board ISS is space weather monitoring the duskside REP eventsRapid 5‐20 s modulations are regularly found in phase at >1.6 and >3.6 MeV detectorsThe rapid REP modulations are useful to diagnose the nonlinear growth of EMIC waves

Three-axis vibration measurement of the linear air-bearing stage demonstrated by utilizing the method of the multi-axis laser interferometer is discussed. In order to detect the X-Y-Z directional vibration of the positioning stage table simultaneously, two-dimensional XY gratings are utilized as the scale grating and the reference grating of the interferometer. The X- and Y-directional positive and negative first-order diffracted beams are superimposed to generate the interference signals on the photodetectors. When the multi-axis vibration is applied to the scale grating, the intensities of the interference signals in X- and Y-directions varied corresponding to the vibration of the scale grating. Consequently, three-axis vibrations of the scale grating can be calculated by processing the X- and Y-directional positive and negative first-order interference signals. In this paper, a three-axis vibrometer based on the grating-interferometer has been developed for measurement of the positioning stage table vibration. The detection method of the vibration based on the Doppler frequency shift has been demonstrated. As an application of the multi-axis grating-interferometric vibrometer, multi-axis vibrations of the linear air-bearing stage are measured by using the developed vibrometer.

Microstructured roll workpieces have been widely used as functional components in the precision industries. Current researches on quality control have focused on surface profile measurement of microstructured roll workpieces, and types of measurement systems and measurement methods have been developed. However, low measurement efficiency and low measurement accuracy caused by setting errors are the common disadvantages for surface profile measurement of microstructured roll workpieces. In order to shorten the measurement time and enhance the measurement accuracy, a method for self-calibration and compensation of setting errors is proposed for surface profile measurement of microstructured roll workpieces. A measurement system is constructed for the measurement, in which a precision spindle is employed to rotate the roll workpiece and an air-bearing displacement sensor with a micro-stylus probe is employed to scan the microstructured surface of the roll workpiece. The resolution of the displacement sensor is 0.14 nm and that of the rotary encoder of the spindle was 0.15μ. Geometrical and mathematical models are established for analyzing the influences of the setting errors of the roll workpiece and the displacement sensor with respect to the axis of the spindle, including the eccentric error of the roll workpiece, the offset error of the sensor axis and the zero point error of the sensor output. Measurement experiments are carried out on a roll workpiece on which periodic microstructures are a period of 133 μm along the circumferential direction. Experimental results demonstrate the feasibility of the self-compensation method. The proposed method can be used to detect and compensate the setting errors without using any additional accurate artifact.

In this paper, a novel Z-θZ micro-stage is designed and constructed by utilizing an impact friction drive. The stage is configured by two driving units, a moving element and a stage base. Each driving unit consists of two PZTs and a friction element. One end of each PZT is fixed on the stage base, and the other end is attached on a permanent magnet as the friction element. The moving element, which is a steel cylinder, is supported and moved by the friction element. Magnetic force generated by permanent magnet is utilized to stabilize the driving condition between the moving element and the friction element for the friction drive. The size of the stage is less than 1 cm3. The stroke and the maximum speed of the stage in the Z-direction are 3.8 mm, 5.7 mm/s, respectively. The stroke in the θZ-direction is unlimited and the maximum rotational velocity is 26 rpm.

A contact stylus-type displacement sensor is proposed for a surface form measurement of micro-structures. The stylus is supported by an air-bearing, thus it can be moved smoothly without friction between the stylus and the air-bearing. In order to reduce the measurement force, a novel controlling technique of a contact force has been developed. During the measurement one edge of the stylus is maintained contact with the measured surface by its own weight. Another end of the stylus is connected with a counter weight by a string and the stylus is hanging on the string in order to reduce the contact force between the edge of the stylus and the measured surface. Measuring force is estimated to confirm the effectiveness of the counter weight. Surface measurement of a steel ball is carried out using the developed air-bearing displacement sensor.

A strain-gauge-type precision displacement sensor, which is developed for a usage of micro-XY stage, is described in this paper. A thin-film strain-gauge element, which is made by Cr-N alloy, is directly fabricated on the base of the strain gauge. The direct fabrication and using the Cr-N element are expected to achieve higher sensitivity for displacement detection and better stability against the change of ambient temperature. In this study, several designs of the thin-film strain gauge, including both of two-gauge-type and four-gauge-type, are prepared to compare sensor performances such as sensitivity, stability and so on. The designed patterns of the strain-gauge element are directly fabricated on zirconia plates by using photolithography processes. The fabricated strain gauges are then evaluated as precision displacement sensors. At first, stability of the fabricated Cr-N strain-gauge-type displacement sensor was confirmed by comparing with the one made by a conventional strain gauge. Resolution of the fabricated Cr-N strain-gauge-type displacement sensors was then evaluated by comparing with a commercially-available laser displacement sensor, while giving sub-micrometer-order deformation to the strain-gauge-type displacement sensor. Details of the design, fabrication and evaluation results of the Cr-N strain-gauge-type displacement sensor are described.

This paper presents an optical probe employed for edge contour measurement of single point diamond cutting tools. The laser beam from a laser diode (LD) is focused by an objective lens to form a small light spot with a radius of approximately 20 μm, and is then received by a photodiode (PD) after passed through the focal point of the objective lens. The cutting edge of the tool, which is placed on a line with the LD and the PD, is inserted into the laser beam section. At an each X-position, the output of the PD is recorded while the light spot is moved along the Z-direction, scanning across the cutting edge of the tool with its rake face aligned in the XZ plane. The Z-position of the cutting edge is evaluated by determining a specific value from the obtained outputs of the PD. The edge contour of the diamond cutting tool can thus be measured by repeating the Z-scanning at different X-positions. Computer simulation was carried out to investigate the influences of error factors on the evaluation of the cutting edge. Experiments were also carried out to measure a round nose of a tool with nominal nose radius of 2 mm.

A compact optical three-axis surface encoder, which can detect displacements in the XYZ-directions simultaneously by employing a scale grating with a short pitch (0.57 μm) and a single laser beam with a short wavelength (405 nm), is described in this paper. This surface encoder mainly consists of a blue-ray laser diode, a pair of two-dimensional diffractive gratings serving as scale grating and reference grating, respectively, and two quarter photodiodes (QPD) utilized for detecting output optical density. The displacements of the scale grating along X-, Y- and Z-directions are measured by analyzing interference signals caused by the phase shifts and light path difference of diffracted beams from the scale grating and reference grating. Basic measurement principle is illuminated, a compact surface encoder is designed and evaluation experiments are carried out.

A three-axis mosaic surface encoder, which can measure the X-directional position and the Y-, Z-directional straightness of the linear stage in a long range, is proposed. The three-axis mosaic surface encoder is composed of multiple scanning probes and a mosaic scale grating. The mosaic scale grating is constructed by placing the multiple two-dimensional reflective-type scale gratings in a line to obtain long measurement range along the in-plane direction of a scale grating. In addition, the optical configuration of the encoder head, which employs multiple scanning probes to be projected on the mosaic scale grating, is proposed so that a long range measurement can be achieved by the mosaic scale gratings. With the proposed encoder head, the measurement information of the X-directional displacement can always be obtained from the probe which is not on the gaps of the mosaic scale grating. The proposed configuration was applied to the three-axis surface encoder, and basic performances of the proposed three-axis mosaic surface encoder are experimentally investigated.

A form error characterization of a reflective-type scale grating, which is used in three-degree-of-freedom (3-DOF) encoders for position measurement of a planar motion stage, is presented. The scale grating has a micro-structured surface, the pitch of which is 1 µm in both X- and Y- direction. The periodic pattern on the scale grating generates diffracted beams when a laser beam incidents to the grating surface. The ±1st order diffracted beams from the grating contain information about the stage motions of not only X- or Y- directional in-plane displacement but also Z-directional out-of-plane displacement, and are therefore able to be utilized for multi-axis position detection. Accuracies of the position detection are mainly determined by a period deviation and a Z-directional out-of-flatness of the scale grating. The form error characterization of the grating is possible by using Fizeau interferometer, although the form error of a reference mirror in the Fizeau interferometer still remains as a measurement error in the form of the measured scale grating. In this paper, a new method was proposed to evaluate the form error characterization of the scale grating for the 3-DOF encoder, while eliminating the form error of the reference mirror in the Fizeau interferometer.

An eccentric error compensation method is presented for the pitch deviation measurement of gears. The eccentric error compensation method mainly consists of the evaluation of the assembly accuracy, the reconstruction of the reference curve and the coordinate compensation of intersection points. The geometrical model of the measurement system was analyzed and the corresponding mathematical model was proposed. A gear with small modulus was adopted as the specimen for the pitch deviation measurement. Experimental results reveal that the values of eccentricity can be extracted from the measured profile successfully and the eccentric error compensation is effective for the pitch deviation measurement of gears.

This paper presents the dynamic response of an air-bearing displacement sensor for on-machine surface form measurement of micro structures. The on-machine measurement system has some merits in terms of measurement efficiency and re-machining for error compensation after measurement. On the other hand, the performance of the contact type measurement system based on stylus methods is dominated by the dynamic characteristics of the system because the system is subject to random vibrations of the machine tool including the spindle during measurement. Therefore, the dynamic response of the system is useful for analyzing the mechanical vibrations of the practical on-machine measurement system. In this paper, the equation of motion for the air-bearing displacement sensor to the excited input displacement is derived and the displacement behavior of the system by using a PZT actuator is investigated within certain frequency ranges experimentally for identifying the dynamics of the system.

This paper describes the analysis and measurement of the dynamic motions of a large-scale rotating roll workpiece, which is used for a large-scale lathe, under the gravity condition. A dynamic model which includes the gravity effect was first established. In order to investigate the behavior which comes from stiffness differences of the journal bearing at the headstock and the tailstock, a spring-mass-damper system was also established. In addition to the simulations, the behavior of the rotating roll workpiece was investigated with respect to the different rotating speed. In the experiment, a mirror finished hollow type roll workpiece with a diameter of 320 mm, a length of 1800 mm, a weight of about 340 kg was fabricated by a large-scale lathe. Five capacitive type displacement sensors were mounted on the sensor holders which were arranged along the axis of rotation of the spindle. The behavior measurement was carried out at 5 sections of the roll workpiece along the axial direction. The rotating speed was set to be 5, 50, 100, 150, 200, 250 and 300 rpm. The dynamic model for the analysis with simulations and the measurement result of the behavior of a rotating roll workpiece according to the different rotating speed are presented in this paper.

A deign study of a thermal-type contact sensor for the detection of small defects, the heights of which are less than 16 nm on the wafer surface, is described in this paper. The feasibility of the contact sensor, which would detect frictional heat generated at the contact with defects, was theoretically investigated focusing on the temperature rise of the sensor element. To investigate the temperature rise of the contact sensor due to the generated frictional heat, both the theoretical calculation with simple model of heat transfer and a simulation with a finite element model (FEM) was carried out. Relationship between the sensor size and the response of the temperature rise of the contact sensor was also investigated by using FEM simulation.

A thermal-type contact sensor was proposed to detect small defects, the heights of which are less than 16 nm, on the wafer surface. The feasibility of the contact sensor, which detects frictional heat generated at the contact, was theoretically investigated focusing on the temperature rise of the sensor element. Simulation results with both the simple model of heat transfer and the FEM model showed that the expected temperature rise of the contact sensor is enough to be detected by the conventional electric circuit.

This paper presents a measuring station based on an atomic force microscope (AFM), which is designed and constructed on a four–axis diamond turning machine for inspection of the cutting edge profile of single point diamond micro–tools. The measuring station is composed of an AFM probe unit for three–dimensional (3D) edge profile measurement and an alignment system with an optical sensor for aligning the probe–tip with the edge top of the tool chip. The alignment system greatly shortens the alignment time, which is essential for carrying out the edge profile measurement by the AFM. Measurement experiments of round nose micro–tools with nominal nose radii of 8 µm and less than 2 µm were carried out to demonstrate the performance of the measuring station.

Two types of micro–ball styluses were fabricated for scanning–type surface form metrology. The micro–ball stylus is composed of a precision glass micro–ball and a shaft made by stainless steel or glass tube. The diameter of the micro–ball was less than 50 µm. The tip angle of the glass–tube shaft was approximately 10 degrees and that of the stainless steel shaft was approximately 50 degrees. It was confirmed that the micro–ball stylus with the glass–tube shaft can tolerate a 90 mN external force applied from the direction with an angle of 45 degrees with respect to the shaft axis, which was much more tolerant than the micro–ball stylus with the stainless steel shaft. To reduce the influence of the stick–slip phenomena caused by friction between the ball and the scanned surface, a PZT actuator was added to the micro–ball stylus, which is called the micro–tapping probe, so that the ball can be oscillated with a high frequency. Experiments of scanning the micro–ball stylus, which was mounted on an air–bearing displacement sensor, over a flat surface were carried out to test some basic performances of the micro–ball stylus.

This paper presents a micro-stylus probe, which is composed of a precision glass micro-ball and a shaft made by a glass tube. The diameter of the micro-ball was 50 m. The tip angle of the glass-tube shaft was approximately 10 degrees. Strength test shows that the tolerance of glass tube micro-stylus against external forces is 90 mN. To reduce the stick-slip phenomena, a micro-tapping probe employing the glass tube micro-stylus and a PZT actuator was demonstrated. The micro-stylus probe was mounted to an air-bearing displacement sensor for scanning surface form metrology. Experimental results showed that the micro-tapping probe was effective for reducing the influence of the stick-slip phenomena.

A new optical two-degree-of-freedom (2-DOF) linear encoder with a mosaic scale grating is proposed to expand the measurement range along the in-plane direction of the grating. The 2-DOF linear encoder has the ability to measure the in-plane displacement along the axis of the scale grating (X-axis) and the out-of-plane displacement perpendicular to the scale grating plane (Z-axis). The measurement range of the optical linear encoder along the X-axis, which is determined by the length of the scale grating, is expanded by using a mosaic scale grating with multiple scale gratings aligned along the X-axis. A new optical configuration of the sensor head, which projecting multiple light probes onto the mosaic scale grating, is presented. The 2-DOF displacements can be obtained accurately from the probe which is not on the gaps between scale gratings. The feasibility of the 2-DOF linear encoder with the multi-probe configuration has been verified by experimental results. The X-and Z-directional resolutions were about 5 nm and 1 nm, respectively. The peak to valley amplitude of the non-linear component was within ±50 nm in the measurement error of the X-directional sensor output, which was obtained by the stitching outputs from the multiple light probes.

This paper describes an overview of the multi-axis grating encoders developed for measurement of stage motions. Two grating mirrors are employed in the grating encoders. One of the grating mirrors is utilised as the scale grating. The other grating mirror is included in the sensor head as the reference grating. The ±1st order diffracted beams from the two grating mirrors are superimposed to generate interference signals, which have information about not only the Z-directional out-of-plane displacement but also X- or Y-directional in-plane displacement. A prototype two-axis linear grating encoder with a software compensation technique for X- and Z-directional measurement, and a prototype three-axis surface grating encoder with a double Y-PD unit design for X-, Y- and Z-directional measurement are then presented.

An optical setup for measurement of the pitch deviation of a diffraction grating has been designed and developed. Multiple autocollimation units are employed in the setup so that the angles of diffraction of diffracted beams can be detected simultaneously. This enables the optical sensor head to evaluate the scale pitch deviation while separating the contributions from the scale local slope and the scale angular error motion that cannot be achieved by the conventional laser diffraction methods. In this paper, firstly, the resolution needed for the angle sensor is estimated using a theoretical analysis. After that, the design of an optical head for the angle sensor is carried out. A built prototype optical head is also used to conduct some feasibility tests, and the measurement of the pitch deviation of a scale grating brought from a commercial optical linear encoder is demonstrated.

It is known that linear motion errors for linear guides can be measured by the autocollimation method. In this case, it is necessary to install a mirror on the measurement target. On the other hand, if a light with a wavelength sufficiently longer than that of the surface roughness of the measurement target is used, the need for a mirror is eliminated. We have proposed an autocollimation method using a mid-infrared laser. In the original prototype of mid-infrared autocollimator, the angle of laser irradiation is 45° to the measurement target. However, this method does not allow us to obtain a long measurement range. Therefore, we construct a system in which the laser irradiation angle is set to 0° by controlling the polarization of light. By using this method, autocollimation is applied to a sample with a root mean square roughness Rqof 0.2 μm, and an angular resolution of 1.1 arc-second is obtained.