Atomic force microscope (AFM) is a useful tool to quantitively evaluate the micro/nano scale interaction between two bodies and they are measured by the deflection of the cantilever at the end by the optical lever method. Since this method are highly sensitive to the deflection angle, there are gap between the real deflection and the deflection obtained through the optical lever method. In order to measure the surface interaction with higher accuracy, it is important to grasp the vibration characteristics of the cantilever and fix the gap. In this study, vibration analysis of AFM cantilever was conducted considering the surface force. The surface force was approximated by the linear spring element with surface force deviation. The results showed that the first mode of the resonance frequency shifted to lower frequency, as the spring constant decreases. The higher mode of the resonance frequency was not influenced by the spring constant. Considering the van der Waals interaction, we found that the distance between two bodies strongly influence the first mode of resonance frequency below nm scale.
To execute efficient and precise handling tasks in micro world, a bilateral system which connects the micro and macro worlds in both directions has been developed. In order to improve the work efficiency, 3-imensional observation of objects in the micro world is necessary. Two images with parallax are necessary for the 3-D observation, but it is difficult to obtain these images under a microscope. In addition, in order for the operator to presence an accurate operation, it is necessary to have an operation that is realistic and does not make the operator feel uncomfortable. In this research, we proposed a method of obtaining parallax images by inserting a glass plate under the microscope, tilting the plate and thus changing the optical path by a small distance. In addition, in order to electrically control the tilt of the glass plate, we developed a swinging actuator driven by voice coils. We also prototyped a swing glass stage and measured its characteristics. To stabilize the feed-back system, the peak of the resonance frequency was suppressed by applying electromagnetic damping. The characteristics of the feed-back system was estimated.
This paper reports the electrostatic vibration energy harvesters(EVEH) indicating broadband characteristic at low frequency using nonlinear spring erects by electrostatic force of electret. In the device, the electret counter electrodes periodically pass each other due to vibration. The electrode period and the electret voltage were adjusted so that a flat region was generated in the potential energy. .In the simulation, when the electrode period was tripled, a six-fold short-circuit current was obtained at 40 Hz. The longer the flat band region of the potential, the larger the vibration amplitude at a minute acceleration.
In cementless hip replacement surgery, the evaluation of the optimal stem implantation into the femur is
subjectively determined by the surgeon. A sufficient fixation force can be obtained by firmly inserting the implant with strong force; however, excess force may cause a femoral fracture. We know empirically that the sound changes as it stabilizes, which has helped to evaluate the appropriateness of implant fixation. We are currently adjusting stem implantation depth with the aid of the change in “impact sound” generated at the time of stem insertion. We have evaluated this impact sound subjectively and used it as information for making intraoperative decisions. The impact sound includes sound of a hammer in addition to the stem and femur. Eliminating the sound of the hammer will improve the accuracy of the evaluation of implant fixation by the impact sound. In this study, we develop tapping hammer that meet our objectives.
In recent years, researches have been conducted to recognize human behavior using wearable sensors for the purpose of health management, work analysis, safety and security, etc. The behavior is so complicated that it has been studied from various aspects such as engineering, medical science or biology. In this study, we constructed a system that automatically recognizes motion by using sensor shoes with multiple 3-axis tactile sensors arranged on the insole in combination with supervised machine learning. We measured the sole forces during the five motion of walking, climbing and descending stairs, going up and down a slope, and built a supervised machine learning model based on those data, and then input test data with unknown behavior to this model. Motion identification and accuracy evaluation were carried out. As a result of the experiment, the identification accuracy of the two types of motions was from 63% to 93%.
The purpose of this study is to scan the surface of a phantom imitating the human body with a probe equipped with a three-axis tactile sensor, and to estimate the inner texture from the acquired data. As an experimental method, a stepping motor connected to a tactile probe scans a phantom containing imitated organs in two directions, and measures shear stress and pressure. From the experimental results, it was confirmed that the shear stress in the scanning direction can easily estimate the phantom inner texture. In addition, it was confirmed that the estimation could be made more clearly by increasing the load at the tip of the probe.
In a micro world such as under a microscope, it is difficult to increase the stiffness of devices. Errors of deformation of tools impair the operability of tasks. Generally, in a macro world where we live, we design the tool to be larger, decreasing the errors by deformation. However in the micro world, using an excessively large tool with high rigidity for a small object leads to decrease of operability. In addition, the operation may be less accurate. Authors propose a compensation method to cancel the errors by reproducing negative elastic properties with a precision stage. In this paper, we analyzed the deformation of the tool and indicated that the error caused by the deformation can be compensated. We reproduce arbitrary elastic properties, controlling precision stage according to the force information detected by a tactile sensor. As a result, not only positive rigidity but also negative one were reproduced.
A phantom for medical training which simulats a human body is used for training of accurate treat. Blood vessels embedded in a phantom are made of tubes whose dynamic characteristics are similar to real blood vessels. But actually, blood vessels are also pulsing along with heart beat and bloodstream. Therefore a heart blood-vascular system with artificial pulses and embedding it in phantom for medical training are required. In this research, modeling of the blood vessel along with artificial pulses was executed. Motor torque of the pump is proportional to driving current, so artificial pulses can be generated by controlling the current. Response of the pulse pressure indicated a first order time lag to a step input. As a result, a bloodstream with pulses were generated by driving the motor with an arbitrary waveform composed of several function waveforms.
Capillary coil for controlling the refrigerant flow is attached to pipe in air conditioning units. Excitation force is
generated in the capillary coil when the refrigerant flows. We calculated the curved pipe pressure by CFD software “PHOENICS” and we also calculated the excitation force of modeled capillary coil using the results of CFD analysis. Calculation results of the excitation force were compared with the measured value by the testing system. We found that the calculation result agrees with experimental result.
A rotary compressor is mounted on an outdoor unit of a residential air conditioner. The main components of a rotary compressor are a motor, a bearing, and a compression unit. A major factor considered as a cause of the vibration and noise generated during the operation of the compressor is considered to be an exciting force generated from the compression unit. Therefore, the purpose of this research is to obtain the excitation force generated during the operation of the compressor by calculation.
Music timbre is changeing depending on keystroke position, rhythm, velocity and length when playing piano．Therefore it is not easy for beginners to learn how to press piano keys accurately and they also cannot easily use both hands at the same time when playing. Thus, it is necessary to practice for a long time to play the piano well. Currently, there are plenty of systems for enhancing playing skill. It is possible to provide more useful assist using haptic feedback when playing a musical instrument. In this paper, a skill evaluation method to play the keyboard is proposed. In order to improve the playing velocity skill, we compared the keystroke’s speed when playing the keyboard instrument and the tactile feedback to change the dynamics of the keyboard. Performance improvement on keystroke velocity using this reserch’s keyboard calibration is examined. Experiments were performed with and without calibration. Results demonstrate a better keystroke speed performance using the proposed calibration.
Recently, increase the aging of a worker is the problem by the influence of decreasing birthrate and aging population. Transportation support by UAV is one of the methods to reduce physical burden. In transportation by existing UAVs, there is a limit to the weight in which transportation is possible.Therefore, we propose a transportation support system using multiple Single-Copter UAVs. In addition, the use of a contra-rotating motor makes it possible to carry a lightweight object with only one motor. In this paper, the attitude control of Single-Copter UAV is used by STA architecture. The STA architecture is possible to consider the state of the environment when cooperative control by multiple Single-Copter UAVs.By performing Neural Network learning and STA in parallel, it can predict the future posture angle and change the posture so that it approaches the target angle. The proposed system is verified using a test bench constrained to 1 DoF. As a result, it was suggested that the attitude control of UAV was possible in 1 DoF by STA architecture.
The purpose of this research is reproduction of thermal sensation when touching an object. It is said that a human thermal sensation when touching an object is perceived within a few seconds immediately after the contact. In order to reproduce the human thermal sensation, it is necessary to reproduce the transient heat transfer that occurs immediately after contact with an object. In this paper, we constructed thermal sensation reproduction device that reproduces skin temperature changes based on the measured skin temperature when touching an object using a Peltier device. Using the device, it was possible to reproduce the thermal sensation when touching an object with different thermal characteristics. On the other hand, to reproduce the thermal sensation after touching an object, it was necessary to speed up temperature response of the Peltier device. Therefore, Therefore, we investigated the parameters that affect the speed of Peltier device temperature control. As a result, the speeding up of the temperature control of the Peltier device is affected by the
magnitude of the driving current.
In recent years, cooperative work using multiple robots, motion strategies were designed in advance to adapt to the environment. However, there is a problem in the fact that conventional method cannot function when encountering unexpected disturbance. In this research, we propose an environment adaptation algorithm based on the imitation of individuality and the maintain of diversity as human social perception. For each individual, a local evaluation is prepared and an operation strategy is designed. The local evaluation value changes according to the speed of each individual and the distance from the goal. Based on this value, personality imitation can be realized. In this paper, we introduced diversity maintenance by weights that change the degree of imitation, constructed a face-to-face traffic simulation, and examined its effectiveness. As a result, the usefulness could not be confirmed by the average number of collisions, but the improvement by the proposed method was confirmed in the total number of reached goals.
This paper describes basic study of sheet attitude during decelerated delivery of the nip transport mechanism. The nip transport mechanism with a pair of rollers is widely used in many devices, such as automated teller machines (ATMs), printing machines, and copy machines. In these machines, a sheet is sometimes nipped by two pairs of rollers at rotating unequal speeds. There are two kinds of the conveyance between rollers at rotating unequal speeds, namely, accelerated delivery and decelerated delivery. The sheet attitude during the accelerated delivery and the decelerated delivery can be changed. In this paper, we performed an observational analysis of the sheet attitude during the decelerated delivery. As a result, we have shown that the transport guide affect the sheet attitude during the decelerated delivery.
To realize an analysis technology that can predict the centering behavior of the elastic belt suspended by crowning roller more accurately, we examined the relationship between the centering action of the belt and the shape of the crowning roller, and the tension, etc., in detail by experiments. And we also studied the analysis method that can predict a deformation of the belt suspended by crowning roller using Timoshenko Beam theory. We found that (1) the radius of curvature of the crowning roller, the roller diameter, the distance between axis, and the tension acting on the belt affect the centering action of the belt, (2) The width of the belt does not significantly affect the centering action of the belt, and (3) The analytical model considering the effect of the tension is necessary to predict the centering action of the belt accurately.
In recent years, the research and development of devices using thin and flexible plastic films as substrates has been actively conducted. However, thin films, which have been growing in demand in recent years, have problems when rolled. Therefore, in this study, the physical properties were measured using a thin plastic film, the stress analysis was performed using the plastic film, and the internal stress of the roll was actually measured to evaluate the effect of thinning. As a result, it was found that the analyzed stress of the winding roll using the thin film was much lower than the measured value.
Recently, copper foil is attracting attention due to the influence of Internet of Things because it has characteristics as a high electrical conductivity. Copper foil is mass-produced by a roll-to-roll production system in which a number of rollers can continuously perform from rolling to winding. However, troughs and wrinkles are generated in the copper foil in the transport process. In order to solve this problem, we have experimentally verified whether a web wrinkle theoretical model can be applied. Using two kinds of copper foils with different materials and thicknesses, the wrinkle generation experiment was conducted. According to the experimental results, when the velocity of the roller was increased, the copper foil B generated wrinkles in the high tension region. Comparing the experimental results with the theoretical prediction model, it was found that both copper foils went in the range of theoretical values. However, the theoretical value and the experimental value are different for copper foil B. This is thought to be due to the difference in the elongation of PET film and copper foil. In the misalignment angle exceeded θ = 0.6 deg from the trough photographs, the size and number of troughs did not change.
The purpose of this study is to investigate the contact mechanism between nanosheets and human fingertip skin controlled to tens of nanometers in terms of friction coefficient under two different conditions, dry and immersed is. Nanosheets of various thicknesses with controlled film thickness were prepared, and the frictional force between the nanosheets and the fingertip was measured using a three-component dynamometer. The contact area was observed with a prism and the contact area ratio was calculated. From the experimental results, comparing the friction coefficient and the contact area ratio of the polymer nanosheet, it was found that the contact area ratio increases as the friction coefficient decreases. In addition, a much higher coefficient of friction was observed during drying than when immersed in water, and the coefficient of friction increased slightly with increasing load during immersion. Therefore, the findings of this study could contribute to the study of nanosheet materials and other skin applications.
To achieve effective lubrication of head-disk interface in heat-assisted magnetic recording (HAMR),
mechano-chemical decomposition of nonpolar and polar perfluoropolyether (PFPE) lubricant films, i.e., Z, Z-tetraol, Demnum, and D-4OH, was investigated using reactive molecular dynamics. By fitting with quantum calculation results, the reactive force field (ReaxFF) for PFPE was developed, allowing simulation of chemical reactions of PFPE lubricants. The results showed that at a temperature of 700 K, pure thermal decomposition of PFPE hardly occurs within the nanosecond heating time of HAMR, whereas mechano-chemical decomposition is highly possible to occur when normal pressure and shear are applied by the head and disk. We confirmed that thermal decomposition is mainly caused by the dissociation of C–O bond at the polar end groups and mechano-chemical decomposition is caused by dissociation of C–O bonds at both the polar end groups and main chains.
In recent years, the improvement of recording capacity of hard disk drives is required. Therefore, the heat assisted magnetic recording (HAMR) was proposed as a new recording method. In HAMR, the laser element mounted on the head slider heats a diamond-like carbon (DLC) film and PFPE lubricant film of the magnetic disks to 200-400 ℃, the damage such as evaporation, thermal decomposition and oxidative decomposition of each material occurs and the magnetic head smear adheres on a slider surface. This smear on the magnetic head may cause hard disk drive failure. It is expected that HAMR will be employed in a helium atmosphere and laser heating will be performed. In this study, laser heating was performed on the disk coated with lubricant in air and helium atmospheres, and environmental gas factors of lubricant smear generated under different oxygen concentrations were analyzed using TOF-SIMS.
In recent years, the demand for hard disk drives (HDDs) has been growing in the midst of a huge
amount of information handled with the development of AI and deep-learning. In particular, a demand
for HDD for data centers is growing, and capacity of HDDs is required. Currently, the phenomenon of
head smear is concerned for the heat assisted magnetic recording (HAMR), which is the proposed
recording method. This problem is caused by the lubricant and diamond-like carbon (DLC) overcoat being
heated to a high temperature, which reduces the reliability of the hard drive. In this study, we analyzed
the materials of head smear in He or air environment using Raman spectroscopy and estimated the
mechanism of the head smear generation from its spectra. As a result, it was found that the head smear
was caused by not only with lubricants but also in DLC. It was found that head smear has hydrocarbon
and lubricant structures. These are often in the air environment, the decomposition of DLC and lubricant
is promoted by the influence of oxygen, it is expected to be those generated.
Toe clearance and MTC are important parameters related to fall-risk. MTC is minimum toe clearance during the swing phase. For daily usable walking assistance system, this study aims to estimating the toe clearance from inertial sensors, such as Inertial Measurement Units (IMU), attached to the thigh and shin instead of the feet. For this purpose, neural network system was introduced; however, differently from conventional data analysis, FFT analysis was conducted to IMU sensor output. This proposal is from considering the periodic characteristics of walking and FFT analysis can utilize whole signal from the IMU sensor output. By taking this proposal, not only MTC estimation but also time-series data for toe clearance become possible. As a result, the RMSE for MTC was 2.70 mm, which indicated the possibility of estimating the time change of toe clearance from the thigh and shin IMU sensors. When only the MTC was used for teaching data, the RMSE of the MTC was 2.41 mm.
The olfactory brain that controls olfaction overlaps with the emotional brain that controls emotions, and is thought to have contributed greatly to the development of the emotional brain. Therefore, the sense of smell is considered to be more connected to emotions than other senses, and attention has been focused on manipulating the psychological state to a desirable state by using scent. However, it is thought that there is a gender difference in aroma. According to Oloveira et al., Women have a large number of neurons and neurons in the olfactory bulb, which play the role of receiving olfactory information, and women are superior in the smell separation test (1). Other studies have found that repeated exposure to odors increased olfactory sensitivity only in postpubertal women. From the previous case, it is considered that there is a gender difference in the intensity and type of emotion that occurs even when the same scent is presented. Therefore, in this study, we aimed to clarify the gender difference of psychological changes caused by scents.
The fall of the patients in the hospitals are one of the main causes of prolonged hospital stay. However, it is difficult for all clinical staff to judge and act at the expert level immediately in aa situation where the condition of patients and environment changes at any time. Therefore, as a clinical safety system that assists clinical staff for an aging society with a low birthrate, we propose and develop a nursing assistant system using artificial intelligence and robot technology . In this paper, we present a study n the design automation of deep reinforcement learning model mounted on the autonomous mobile robot assisting to reduce patients' fall risk. First, This method observes state transitions, and actions of veteran clinical staff(experts). Nest, estimates reward functions and action vectors using deep inverse reinforcement learning. finally, deep reinforcement learning performs using these, and the reward function and the action vectors are updated. The results show that not only reward definitions that were designed by humans, but also action definitions are automated. It also suggests that intervention strategies, such as the use of "leverage principle" behind veteran clinical staff behavior, can be acquired. This study is useful for expert behavior and also for human resource education.
We investigate complex behavior of rotating flow in hard disk drive (HDD). The flow is driven by a stack of rotating disks mounted in a non-axisymmetric enclosure. The recent HDDs are equipped with more numbers of disks mounted in particular outer dimensions in order to fulfill the increased demands for higher storage capacity. As the increase of the number of the disks mounted in a single enclosure, the spacing between the disks has been reduced, and hence the gas flow has to go through narrower space in the complex internal geometry. In the present study, we focus on the flow behavior with different disk spacings in a simplified HDD model. The control of the disk spacings were realized by mounting either two or three disks in a non-axisymmetric enclosure. We performed flow experiments using the transparent HDD model and working fluid with matched refractive-index. Qualitative information on the flow was provided based on flow visualization, and quantitative information on the velocity fields was obtained using particle image velocimetry(PIV). Flow behavior is investigated between the disks at different sets of Reynolds numbers, angles of inserting arms and observation planes. We discuss on the evolution of the flow velocities at different circumferential angular positions.
3D Printer using the Fused Filament Fabrication method has expanded its application to not only personal but trial and commercial products for industry. For precision printing, it is necessary to understand the discharge mechanism and how to control material feed speed. It is difficult to estimate mathematical expression which is used for designing a control system because of its complicated physical phenomenon such as melting of material and behavior of viscous fluid. In former study, there are some study to clarify dynamic characteristics of discharge process from experimental data. However, there are few cases of controlling the material feed with the estimated model. This report describes the estimated mathematical expression of the discharge mechanism from experimental data, and the results of experiments using feedforward control of material feed. As a result, the printing precision was improved.
In this study, the purpose is to analysis influences that give plant complexity(model order) control performance in
data-driven control via system identification. In the framework of maximum likelihood identification, based on the
concept of information criterion, the relation of the control performance and the model order is derived, and it is shown that high order model is tend to fundamentally disturb to make the control performance best.
In the digital control, a stable inverse model is required for the output perfect tracking control.
However, the inverse model of a conventional two-inertia system with PWM-type input is unstable.
In this research, we propese a method to obtain an invese model utilizing degrees of freedom of
The kinesthetic illusion (KI) is described as flowing: when a suitable vibration stimulus is applied to tendons or muscles, the stimulus tends to feel as if the stimulated tendons or muscles were stretched and related limbs were moving. It is expected that rehabilitation will be promoted by the occurrence of movement image. In this study, we are attempting to investigate enhancement process of the movement image induced in a brain of a human subject experienced KI for the first time while performing the number of experiments. For the abovementioned investigation, we performed a series of five experiments applying a vibration stimulus to the tendon of right flexor carpi radialis muscle (FCR) of each human subject using a desktop device inducing KI equipped with a voice coil motor to evaluate sensation of KI with magnitude estimation. As a result, it was found that the intensity of KI occurrence was increased with implement number of the five experiments.
We have been researching and developing a three-axis tactile sensor capable of being mounted on a small humanoid robot hand in order to perform work in human society. This sensor is equipped with an optical waveguide and a skin rubber on it; an external force makes the skin rubber come into contact with the optical waveguide illuminated from its end to make light leak from the back surface of optical waveguide and to be measured by a camera. The normal and shearing forces are measured by the brightness value and the centroid movement of the light distribution, respectively. In the previous study, there were some problems related to large thickness of the sensor, narrow sensing area and accuracy of the optical waveguide. In this study, in order to solve the abovementioned problems, a new sensor was designed to improve the optical waveguide was manufactured by thinning the mounted camera and changing the sensor design. As a result of the experiment, it was confirmed that the thickness was reduced to around 1/3, sensing area was enlarged to 4 times and sensing accuracy of normal force was enhanced with formulated equations.
A method of recording the tactile sensation felt by an operator during works is effective to record and reproduce the skills of craftsmen and advanced techniques. In this research, we develop a sensor identifying the magnitude and direction of the force from the nail color change using the phenomenon, in which the nail color changes due to the applied force to the fingertip. Thus, we developed a prototype of a nail color sensor equipped with a miniature CMOS camera and a green LED, and collected a dataset of normal force and nail color image variation on index fingers using an electronic scale. The obtained dataset was learned by Convolutional Neural Network (CNN) to determine applied normal force from the images. As a result of simulations, the root-mean-square error (RMSE) was about 0.54 [N] in the range of 0-10 [N].
A haptic interface is an interface that feedbacks the feeling of touching a virtual object to the user. A cable-driven haptic interface is an interface that displays force by tension, and has large work space and output power. In the conventional control method of the cable drive haptic interface, the end effector was fixed with a constant tension. With this method, The end effector is freely maneuverable, but resistance occurs when approaching the boundaries of the haptic range. In this paper, we propose a method to eliminate the resistance that occur during operation. First, we eliminated the resistance created by constant tension. Next, we reduce friction resistance with assist. Finaly, the resistance to the coordinates was successfully eliminated by the resistance compensation. In addition, there is a possibility that the resistance has been successfully reduced by the resistance reduction assist. Therefore, the proposed control method improved the haptic transparency and enabled the display of smaller forces.
When human interacts with robots or machines, many skills such as cognition, planning, and control are
involved. However, it is difficult to perform in every single one of these fields. Therefore, assist regarding
human-machine operation has been actively researched. For instance, a method used to feedback surrounding
information using a camera is used in automobiles. However, it has been reported that this method reduces
human concentration. In order to solve this problem, assist methods using tactile feedback and force feedback
has been proposed and demonstrated their usefulness as a way for humans to obtain feedback more naturally.
Among them, we focused on subliminal calibration. Subliminal calibration is an algorithm that focuses on the
process of acquiring skills and determines the value of the calibration so that the process doesn’t disturb the
operator. The purpose of this research to enhance the operator’s skills in order to help him operate machines at will. In this paper, we investigated the change of the personal model in response to the dynamics change. As a result, it was confirmed that the personal model followed the dynamics by subliminal calibration. In addition, it was suggested that the performance could be improved by using the aforementioned results.
Learners of machine operation need to learn the characteristics of the operating machine system in order to
realize the intended operation. When machine operation is required for both hands, it is necessary to design
a system that considers both hands. However, it is suggested that different operation characteristics appear
depending on the dominant hand and the non-dominant hand. Therefore, when performing operation with both
hands, we aim to acquire early operation by learning one-handed operation pattern and applying it as support to
the other handed operation. In this paper, we suggested the support of bimanual operation system characteristics
acquisition by using a two-dimensional targets tracking task. Results show bimanual operation support.
Various gaze estimation methods have been proposed, but they have not been evaluated well in random
environment, and their estimation accuracy are not sufficient. We developed a gaze estimation method using
convolutional neural network based on left and right eye images. In addition, we evaluated the present method with a cross-dataset evaluation using MPIIGaze and performed cross-validation using a dataset of eye images obtained in unrestricted daily settings. The results of this study are summarized as followings. First, we created a learning machine model that estimates the gaze direction of each of the left and right eyes from both eyes images, using a convolutional neural network. The accuracy was 10.3°, which was equal to or greater than the previous excellent gaze estimation method. Second, we compared the model with the input of both eyes and the model with the input of one eye. As a result, it was found that the accuracy of the model using both eyes images was 54.2% better than the accuracy of the model using one eye image. Furthermore, it was found that the accuracy especially in the horizontal direction was improved. Finally, in the cross-dataset evaluation, the accuracy in the vertical direction is better than the horizontal direction, which is different from the result that the horizontal direction is generally better than the vertical direction. On the other hand, the within-dataset evaluation showed the opposite result. It is indicated that the vertical estimation in the proposed method is more flexible to environmental variations than the horizontal estimation.
A highly-responsive control method of network distributed controller for complex working robot has been developed to guarantee response performance of input-output (I/O) control for devices connected to each slave module included in the controller. We developed a tree-topology network via point-to-point connections that is designed to avoid collision of communication signals in a network. We also developed a data relaying method that change between a bit-by-bit tranfer control and a packet-by-packet tranfer in each slave module and a communication control that uses the data relaying method to avoid collision between a cyclic transmission and an event-driven transmission. We implemented our communication method in a field programmable gate array (FPGA) to enable development of a fast responding network in real systems.
The authors previously proposed a topology optimization method applying four conditions of the desired structure using the load transfer index Ustar (U *). In this paper we propose a new method to classify structures based on U* topology optimization. Our method is based on the integration of two structural systems. Whereas a primary structure serves as a load path, rendered from the conventional topology optimization based on U*, secondary structures defined by straight members serve to enhance the load transfer of the primary structure. Topology optimization calculations based on U* were performed for secondary structures then confirmed the improvement of the load transfer on the primary structure and the increase of the specific stiffness of the entire structure. Our proposed method is potential to perform topology optimization of integrated complex mechanisms, and to scale into large-scale systems.
web article, an exhibition investigation, articles were collected for a lecture document using Microsoft Corporation OneNote, and a technical information database of 38.3GB in capacity was constructed. There were 965 pages of data in conjunction with < IoT <, and it was < production or production < (55%), < robot or sensor <
(52%), < AI < (49%), < image or camera < (41%), < inspection < (9%), and, as for the co-occurrence word with < IoT < , < AI* robot * image < (7%) increased in much order in that. After using 5-10 < IoT < -related information from a database by every lecture, 2.75 (2018) improved in 3.18 (2019) in a student questionnaire < interest, interest < item (four points of perfect scores). IoT example introduction was effective.
This study aims to examine the relationship between visual fatigue and prefrontal cortex (PFC) activity during a backlit text reading task. We conducted a 10 min luminescent sentence reading task in a dark room. Time-course of oxy-Hb in the PFC was measured using a 22-channel wearable near-infrared spectroscope (NIRS). Subjective fatigue was assessed using the “Jikaku-sho shirabe” questionnaire. The critical flicker-fusion frequency (CFF) and LF/HF were assessed as objective index of fatigue and autonomic nervous system. 192 trials consisted of twelve healthy young volunteers and twelve LED treatments were analyzed. In the analysis, a linear non-gaussian acyclic (LiNGAM) model for causal discovery was introduced in addition to the correlation analysis. Our results suggested that the development of visual fatigue and central fatigue is related to the deactivation conditions in the medial PFC and Left PFC.
We propose an artificial skin with a flexible thin film and a tactile function that requires no external power supply. The proposed skin is made from a lamination of an electret, an elastomer and two electrodes. The electret is a material in which electric charges are stored semi-permanently. In this study, an electret with a thickness of 15µm was made by corona discharge after dropping amorphous fluororesin on a 10µm thick copper electrode. After that, an elastomer was applied to the opposite electrode with a thickness of 20 µm. These were laminated each other to produce an artificial skin. The results of experiments in which the pressure was applied to the prototype skin showed that the detected, voltage was 2V, which was sufficient to used as a sensor for detecting the contact.
Recent years, cars are equipped with various sensors, and various advanced controls are performed. In addition, “autonomous cars” are paid attention with the development of the IoT society, and vibration power generators and sensors for incorporating into tiresto more advanced control are required. Therefore, we made a prototype of the energy harvesting device for incorporating into the tire using triboelectrification phenomenon, performed tire running test on a drum and a numerical analysis. As a result, we found that it is important to use the silicone rubber with low hardness in order to improve the output of the tribocharge sensor mounted inside surface of the tire.
Interest in energy harvesters has grown rapidly over the last decade. In this study, we fabricate and evaluate piezoelectric energy harvesters (PEH) fabricated from Pb(ZrTi)O3 (PZT) thin films on stainless steel foils. The PZT thin films were deposited onto (Pb,La)TiO3/Pt/Ti-coated stainless steel substrate by RF-magnetron sputtering. Parallel and series connection of eachPEH enabled the output power increase as high as turning on a LED.
We developed a novel vibration-sensing device, which is based on giant magnetostrictive effect. The device can
generate large voltage in principle, because the magnetostrictive rod can generate large variation of magnetic flux
density even by the small and low-frequency vibrations of the bridge girder. The device, therefore, can be used as power generator to supply power to a storage battery, when the device is not used as a vibration sensor, in order to drive the its electric circuit. We carried out field test for the developed device. We describe some test results in this paper.
A laser-scanning projector displays images by combining red, green, and blue laser beams into a single
beam and by scanning the beam in a raster pattern by using a two-axis movable mirror. This projector
requires opto−mechanical assembly technology that aligns the optical axes of the beams and maintains
this condition despite environmental changes. One main reason for the optical axis alignment deviating
is the difference in the amount of warps of laser chips between the red laser beam and the others during
temperature changes. A set of laser holders is thus proposed whose right-to-left ratios of widths around
the laser diode differ in accordance with the lengths of laser chips. The proposed laser holders with
asymmetric thickness distributions can compensate for the difference in the amount of thermal warps of
laser chips between them. The calculated results show that using the laser holders with asymmetric
thickness distributions can reduce relative optical axis deviations below 30% compared with using laser
holders with symmetric thickness distributions in the temperature range of 0 to 65 °C.
Roots are essential parts for plants not only to support their body but absorb water and nutrients. The roots grow under various influences from soil during the growth process, and it needs a certain degree of strength for roots to grow. However, it is difficult to analyze roots in soils which are naturally opaque, and mechanical properties of growing roots have not been quantified. In this paper, we describe an on-chip system using micropillar which is applicable to estimating the mechanical properties of growing roots. We calculated the displacement of the micropillar during contacting with the root based on the finite element method and derived the equation to estimate Young’s modulus of root. In growth experiment of the plant Arabidopsis thaliana, Average root diameter and estimated Young’s modulus is 137 μm and 1.3 MPa nearby the root tip, and 129 μm and 0.63 MPa nearby the seed. It can be considered as a result of optimization of roots against mechanical stress from micropillar. Significant difference is not observed between different boron conditions in root diameter and Young’s modulus. By applying this method, it is expected to contribute to the cultivation technology under various soil conditions.
With the development of processing technology, the sliding gap between machine elements has become smaller with the miniaturization of machine elements, and precision mechanical systems down to the nanometer order have also been developed. For the operation of a machine with nano sliding gap, the surface force between machine element surfaces is more important than the body force. Since the surface force strongly depends on the size of the gap, quantification of the gap dependence of the surface force is indispensable to establish the design theory of a micromachine having nano gaps. For that purpose, a highly sensitive force measurement with accurate gap control is required. In this study, we proposed a new AFM probe with the accurate gap control and highly sensitive surface force measurement. Using the proposed method, we measured the gap dependence of the squeeze force, which is an important surface force for nano-gap lubrication.
Low friction of DLC coatings under boundary lubrication with organic friction modifiers, such as fatty acids, is
important for industrial applications. This work aims to make clear the effect of fatty acid chain length on their tribological properties on DLC coatings, a-C:H and ta-C, when fatty acids are used as additives. In this study, hexadecane was used as the base oil, while fatty acids with different carbon number were used as the additives. The friction coefficient was measured using a self-developed pin-on-disk reciprocating nano-tribometer. We found that friction coefficient decreased when fatty acid chain length increased both on SUJ2 steel surface and on a-C:H coating surface. However, friction coefficient increased once the carbon number exceeded 16. The lowest friction coefficient was found when palmitic acid was used, which indicates the importance of correlation of chain length between the base oil and the additive. Although ta-C showed lower friction than a-C:H and SUJ2 for a given lubricant, it seems that fatty acid did not reduce the friction further when used as additives on ta-C coating surface comparing with the base oil.
Nanopore sequencer is expected as a core technology for realizing medical treatment based on genome information. In order to improve the analysis efficiency, it is necessary to be able to analyze a large molecular size genomic DNA (large molecular weight DNA) with one molecule. Large molecular weight DNA has a random coil structure in a stable state. Therefore, it is indispensable to establish the technology to extend the random coil-shaped DNA molecule linearly in order to realize the analysis with the nanopore sequencer. In this study, we experimentally verified the effect of migration conditions on the elongation rate of DNA molecules that elongate during electrophoresis in a nanoslit. The results showed that DNA elongation was significantly affected not only by the geometric conditions of the flow channel, but also by the electric field distribution (position within the nanoslit) and the migration speed.
In this study, we stretched and immobilized a 48.5 kbp-DNA molecule using a pressure flow and a gas-liquid interface movement in a microchannel. A chip device with a straight microchannel was fabricated by transfering Si mold created by a photolithography to PDMS. The depth and width of the microchannel were 2 μm and 100 μm, respectively. We controlled the velocities of the pressure flow and the gas-liquid interface by controlling applied pressures into the microchannel in order to investigate the dependence of stretched rate of the DNA molecule on the velocities. We measured the sizes of stretched and immobilized DNA molecules in the microchannel at each applied pressure by analysing the fluorescent images obtained using a fluorescence microscope. We indicated that the increase of the applied pressure improved the stretched rate of DNAs and achieved the stretched rate of 70 % under the condition of 1150 μm / s (600 mbar).