A single spherical synchronous actuator can drive multiple degrees of freedom. This simplifies the mechanism and is expected to be applied to industrial robots. Position control of the actuator is performed using torque maps, which are torque data in each posture. However, measurement errors in the torque map reduce control accuracy. To solve this problem, a new 2-DOF control method using a deep reinforcement learning algorithm was proposed. However, that method could not control 3-DOFs because of the local optimum solution. Therefore, we extended this method to 3-DOF and investigated a new reward function that can be driven with high accuracy. As a result, 3-DOFs could be driven with an average angular error of about 0.4 degrees.

　In recent years, with the increasing electrification of automobiles, highly efficient traction motors have been actively developed. We focus on a variable flux motor with a draw-out mechanism. In this paper, we propose a new structure to increase the efficiency of variable flux motors with a draw-out mechanism. We design a new structure suitable for both low-speed and high-speed operations by combining rotor cores with different geometries and torque constants. We compared our new model with a conventional inner permanent magnet synchronous motor in terms of efficiency and variable flux ratio. We found that our new rotor structure can be used in a draw-out variable flux motor to achieve high efficiency in both low-speed and high-speed ranges. We also confirmed that the combining rotor with different torque constants increases the variable flux ratio.

　It has been reported that nonlinear waves called solitons can be observed on a nonlinear LC ladder circuit using nonlinear capacitors and linear inductors. The authors have previously proposed an inductor whose inductance varies exponentially by utilizing the magnetic saturation phenomenon of the iron core and the permanent magnet flux. We named it the permanent magnet flux biased (PMFB) inductor. Numerical calculations have shown that magnetic solitons can exist even in a nonlinear LC ladder circuit with PMFB inductors and linear capacitors. In this paper, we fabricate a nonlinear LC ladder circuit using some prototype PMFB inductors and linear capacitors. Then, we measure the excitation of magnetic solitons on the nonlinear LC ladder circuit. Furthermore, we confirm that the measurement results are consistent with the simulation results.

　This paper describes a new shape of an aluminum ring that can be suspended magnetically by the AC ampere maglev method. This method uses a first AC magnetomotive source and a second AC magnetomotive source with the same frequency and appropriate phase difference. The magnetic flux from these sources acts on a highly conducting object to generate an electromagnetic force. This method allows a specific object (a single aluminum (Al) ring) to be pulled up vertically against gravity. However, so far, this method has not been able to stabilize the object passively in all directions. This paper's newly proposed conducting object is a squirrel-cage shape Al ring. By three-dimensional electromagnetic field analysis, we investigate the possibility of a completely passive stabilized magnetic suspension for the proposed Al ring.

　An inchworm-type micro-motion robot (inchworm) is studied for the application of positioning devices or moving mechanism in a small production system. The inchworm consists of electromagnets for clamp mechanism and piezoelectric actuators for moving mechanism, and has an unlimited operating area based on the principle of the inchworm. The drive frequency of the inchworm is limited by the transient phenomenon of the electromagnets and piezoelectric actuator. In this paper, the displacement of the piezoelectric actuator is extended by considering the strain characteristic of the piezoelectric actuator, which increases the velocity of the inchworm. By the use of the strain characteristic called butterfly curve, the displacement in a single control cycle is improved. The details of the strain characteristic by rectangular waves and the control of inchworm with piezoelectric butterfly curve are described. The control voltage applied to the piezoelectric actuator is determined experimentally, the deformation of the piezoelectric actuator in one control cycle is increased, and some experimental results show the improvement of the displacement of the inchworm.

　Wireless power transfer via magnetic resonant coupling can be used to supply power to a mobile robot within a few meters of a transmitter coil. However, when the robot moves or its power consumption fluctuates, its input impedance varies greatly and power reflection occurs in case of impedance mismatch. Therefore, we propose the use of multiple identical driver coils on the transmitter side in order to match the input impedance. The input impedance is matched and power reflection is eliminated by switching driver coils, i.e., regulating the coupling coefficient between the driver and the transmitter. In addition, the winding number of the receiver coil can be switched to relax the design condition of the drive coil. The experimental results showed the input impedance was well-matched automatically under the varying distance and load resistance. Therefore, the proposed system was expected to solve the power reflection issues in practice.

　We have proposed a new position sensorless control method under vector control that can be applied to a 6-phase 12/10 SRM by applying an extended induced voltage method. This control method requires inductance for angle estimation. However, it is not clear how to calculate the inductance of a 6-phase 12/10 SRM under vector control. In this paper, we calculate inductance using three different methods, and their effectiveness is investigated. The inductance which is obtained from the voltage equation decreased the angle estimation error in a finite element analysis under sensorless vector control.

　Electromagnetic waves are widely used in several applications. However, many unanswered questions remain about the effects of electromagnetic waves on living organisms. One of the investigations of such biological effects is the evaluation of behavior when a living body is exposed to electromagnetic waves. In a previous study, it was suggested that magnetic fields with a frequency of 400 kHz, exposure time of 24 hours, and magnetic field strength of 10 A/m may affect the behavior of mice. In the present study, we investigated the physiological significance of the influence on mice behavior under the same conditions. Mice with a locomotion meter implanted in their back were placed in a cage that generated magnetic field. We then compared the results with spontaneous brain substance in the absence of magnetic field exposure.

　Aiming at the control of a powered prosthetic hand, this paper reports the development of a tactile sensing system that estimates the motion intention of the prosthetic hand user. Tactile sensors using Polyvinylidene Difluoride (PVDF) film were developed to detect the forearm surface tactile features caused by muscle contraction of the forearm. A neural network was used to classify hand motions using the forearm surface tactile features as inputs. Number of sensors and sensing location on the forearm were discussed in depth in the paper. Experiments showed that by using only 2 tactile sensors placed roughly above the location of the flexor carpi radialis muscle and the extensor carpi radialis longus muscle, the system can classify 6 types of hand motions at an accuracy of about 90% from experiment participants without intensive training.

　A single 3-DOF spherical actuator can drive three degrees of freedom and is expected to be applied to robot eyes and positioning mechanisms. However, it is difficult to miniaturize the actuator because it has a complex structure with many coils and permanent magnets arranged three-dimensionally and is controlled by a large drive unit. We proposed a 4-phase 3-DOF spherical actuator that can be driven by only one 4-phase inverter. The actuator consists of four coils and four permanent magnets, and achieves 3-DOF rotation with a simple structure. This paper describes the change in torque characteristics when the coil shape is changed. The torque characteristics are investigated using a three-dimensional finite element analysis. In addition, the variation of inductance characteristics during rotation is investigated.

　In order to construct a system with multiple-degrees-of-freedom by using the motors with one degree of freedom, the same number of motors as the degree of freedom is necessary. On the other hand, because a spherical motor has three degrees of freedom, it is possible to realize a system with three degrees of freedom by one spherical motor and, therefore, it can reduce the size of the system. A spherical speed reducer is necessary to increase the output torque for a multiple-degrees-of-freedom system. We proposed a spherical speed reducer capable of decelerating in the same ratio independent on the rotation axis and demonstrated its applicability by speed reducing experiments using a prototype speed reducer. However, when the reduction ratio becomes large, the entire mechanism of the speed reducer will become large. In this study, we have investigated the optimization of the sphere arrangement so that the entire mechanism can be made as small as possible. This paper applies a discrimination method using Hesse matrix to identify a convex region for applying the sequential quadratic programming method that can be applied only for a convex region of objective function. This paper shows some optimization results using the sequential quadratic programming method and the arrangements of spheres corresponding to the optimization results.

　This paper describes a novel method of controlling structural vibration using magnetic levitation technology. A floator is attached to the ceiling of the structure. When the floator levitates, friction with the ceiling becomes zero, and friction occurs when the floator contacts with the ceiling. By switching to the contact state when the product of the displacement and velocity of the ceiling is positive while switching to the non-contact state when the product is negative, then the vibration is suppressed by converting the vibration into heat. In this paper, the vibration suppression effects for a two-story structure model excited by standing waves and white noise are verified by experiments and simulations. The results show that the magnitude is reduced by placing the floator in the antinode of the vibration mode and switching with the mode frequency. Moreover, it is suggested that the reduction effect varies depending on the normal force at the contact point and optimal values exist.

　We proposed a new transmission to control the flow difference between left and right pumps in total artificial hearts. The transmission consists of input and output shafts, magnetorheological fluid, and electromagnets with adjustable current and position. A motor rotates the input shaft of the transmission. The transmission transfers the torque to the output shaft that rotates with decelerated rotational speed according to the flow resistance of the magnetorheological fluid. First, we measured the output rotational speed when load torque is 5 mNm, and the input rotational speed was 2000 rpm. The rotational speed difference between input and output shafts changed from 450 rpm to 6 rpm when we increased the electromagnet current from 0.4 to 0.55 A. The difference changed from 2 rpm to 219 rpm when we moved the electromagnet position from 2 to 9 mm. Also, we analyzed that magnetic flux density distribution change according to the current or electromagnet position by 3D computational magnetic field analysis. These results show that magnetic flux density distribution affects the output rotational speed. The yield stress is identified based on the measured and analyzed results. In this paper, we show that the developed transmission is enough small and has sufficient transmission performance.

　Multi-degree-of-freedom (multi-DOF) spherical actuators have been developed for the fields of robotics and industrial machines. We have proposed an outer rotor type three-DOF spherical actuator that can realize a high torque density. Each coil input current is calculated using a torque generating equation based on the torque constant matrix. The permanent magnet type actuators have a problem with generating unexpected cogging torque due to various manufacturing errors. Manufacturing errors mainly mean differences between the ideal dimensions at the motor design stage and the actual dimensions in mass production. In this case, the actuator would exceed the limitations of classical proportional-integral-differential (PID) controllers. In this paper, we propose a current compensator using reinforcement learning by introducing a deep neural network through dynamic analysis and measurements on a prototype.

　In this paper, we study on an electromagnetic energy harvester which is oscillated by speed ripple of AC motors. Motion and circuit equation for the motor and harvester are derived according to Euler-Lagrange equation. The principle of electrical power generation is presented. Numerical computation employing MATLAB/Simulink reveals that the active Coriolis force decreases the original motor torque unnecessarily and expected power generation is unsuccessful. On the other hand, the computation also reveals the reactive Coriolis force is able to suppress the motor torque ripple.

　Increased iron loss in the magnetic core of high-speed rotating motors is a problem, and eddy current loss accounts for the majority of this. Therefore, an ultra-thin electrical steel sheet with a reduced thickness has been developed, and its effect has been recognized. However, it was limited to small magnetic cores due to the restriction that wide steel plates could not be manufactured. A wound laminated core made of ultra-thin electrical steel strips has been developed to further increase the size of the core. In this study, we measure the magnetic properties of a 0.08 mm ultra-thin electrical steel strip wound laminated core with respect to the excitation frequency, and compare it with a conventional laminated core to clarify its usefulness. Furthermore, the wound laminated core is evaluated from the viewpoint of low iron loss by comparison with wound laminated cores having different thicknesses. From the measurement results, it was found that the eddy current loss of the wound laminated core made of ultra-thin electrical steel strips is suppressed and the core utilizes the magnetic characteristics of the single sheet.

　This paper describes a method to analyze a DC electric field generated by an electric railway considering an influence of constructions. The finite element method is effective to solve a problem including the constructions of an arbitrary shape, however the analysis becomes time-consuming if the problem includes the steel material having fine structure such as reinforced concrete. The authors introduced effective modeling methods of the concrete structures such as a concrete pole and a lining concrete installed in a tunnel, and the effectiveness of these methods is confirmed by numerical experiments. The electric field along the electric railway is effectively analyzed by using these methods, and suitable positions to confirm a live voltage line without contact by detecting the electric field are discussed.

　Recently, a new treatment method using atmospheric pressure low-temperature plasma (ALTP) has been attracting attention. We focused on lung adenocarcinoma, which has been the most common site-specific cancer patient in Japan since 1998. All the current treatment methods are highly invasive and their side effects on the body are a challenge. Therefore, I propose a novel method of applying ALTP as one of the less invasive treatment methods. However, the detailed mechanism of action remains unclear, with the difference in effects depending on the cancer type. In this paper, we describe the effect of culture medium after ALTP irradiation on human lung adenocarcinoma cells after irradiation. The evaluation methods include the effect on the number of viable cells, gene expression analysis of apoptosis-related genes, and the effect on cell migration ability to elucidate the mechanism of action.

　Since the vehicle body of ultra-compact mobility is lightweight, there is concern about degradation of ride comfort due to vibration from the road surface. There have been reports on active seat suspension as a means of controlling vibration for occupant, however only in the vertical direction. In addition to vertical vibration, vibration in rotational directions such as roll, pitch, and yaw also deteriorate ride comfort. Furthermore, it has been reported that the human perception of vibration is different in the vertical direction with respect to frequency from that in the rotational direction, such as the pitch direction, which is input during acceleration. Therefore, this paper proposes an active seat suspension system that controls vertical and pitch vibration, and analytically clarifies the vibration characteristics of the model when the optimal control is applied. Furthermore, the output voltage of the voice coil motor of the active seat suspension is limited due to its small size. Therefore, the variation of the frequency response within the limited range was investigated.

　To drive linear switched reluctance motors with high thrust and high efficiency, it is necessary to switch the phase to be excited appropriately according to the mover position, and a position sensor is usually used. However, the position sensor has problems such as increased cost, increased volume, and decreased reliability. In this study, we aim to drive by the position sensorless control method that estimates the mover position from current and voltage for driving using the mathematical model of the magnetization curve. First, we derived the equation for calculating mover position using the mathematical model of the magnetization curve. Next, we measured the magnetization curves of the experimental machine and examined the position estimation error caused by the mathematical modeling. Finally, it was confirmed that the experimental machine could be driven well under position sensorless control up to the rated velocity.

　Thin flexible steel plates are widely used in the production of industrial products. When flexible steel plates are processed or transported by rollers, the steel plates may cause minor scratches. A non-contact way of transporting steel plates using electromagnetic force has been proposed as a solution to these problems. In the previous system for magnetically levitating flexible steel plates, it was difficult to levitate thinner steel plates. To solve this problem, a magnetic levitation system by horizontal electromagnet was proposed. This system is suitable for flexible steel plates and uses electromagnets installed in the horizontal direction. It is possible to reduce the vibration of flexible steel plates because the tension force suppresses the deflection of the plates. In this paper, optimal control method was applied to proposed magnetic levitation system in order to levitate by low steady current. Moreover, levitating stability in conditions of low steady current was investigated by experiments.

　A magnetic-geared motor with controllable maximum transmission torque (MGMCMTT) is proposed. The MGMCMTT can control the maximum transmission torque utilizing DC currents. In addition, it has been reported that the torque on the low-speed rotor due to coil currents is dominant, and the relationship between the phase angle difference and load is different from conventional magnetic-geared motors. In this paper, a mathematical model of the MGMCMTT is created, and the relationship between the phase angle difference and load is compared with that due to finite element analysis under vector control.

　For a totally-implantable artificial heart (TIAH), the transcutaneous energy transmission system (TETS) and the transcutaneous communication system (TCS) are useful to reduce the risk of infection. Integration of TETS and TCS is expected to reduce patient’s burden, including miniaturizing the device. We have studied the two turns of the outer circumference of figure-eight coil for the integration of transdermal energy transmission and transdermal information transmission. In this study, the design of cut the outer circumference of two turns of the outer circumference of figure-eight coil for information communication in the 429 MHz band and the evaluation of simultaneous transmission of energy and information for driving an artificial heart in a quasi-biological environment using pig skin.

　The goal of this study is to investigate the application of optimization algorithms and their employability in manufacturing. Genetic programming, which is performed in this study, can simulate the evolutionary process of organisms in nature on a computer using a population of individuals with genetic information to search for the optimal solution. In this study, an axial-gap motor with a low profile and high output is aimed, and genetic programming is used to accomplish multi-objective optimal design, utilizing the following four objective functions: average torque, torque ripple, cogging torque, and iron loss. The design aim is the shape of a permanent magnet and teeth, and the analysis is performed using the three-dimensional finite element method. As a result, a model was developed, in which each attribute was improved with a maximum gain of 5.01 % average torque. Furthermore, the significance of this method was demonstrated by visualizing the high-dimensional optimization result data via dimensional compression.

　The demand for artificial hearts is increasing as a bridge to heart transplantation. Current artificial hearts have problems such as infection caused by the driveline and reduced quality of life. Transcutaneous energy transmission systems have been proposed to solve these problems, but they have problems such as insufficient transmission efficiency and misalignment. This paper describes the parameter changes of an "α-coil," which is a coil with two or more spiral coils stacked on top of each other. The transmission efficiency was improved by 13.0 % without changing the size of the coil system compared to the conventional spiral coil when used on the secondary side, and the reduction in efficiency due to misalignment was also confirmed.

　In thin steel plate production lines, contact conveyance by rollers is used, so scratches on the surface of the plates and plating defects are problems. Therefore, non-contact magnetic levitation conveyance of thin steel plates using the attractive force of electromagnets has been proposed. We studied a magnetic levitation system for thin steel plates that uses both electromagnets and permanent magnets. We investigated the effect of a permanent magnet arrangement optimized by a genetic algorithm on the levitation performance of steel plates. As a result, it was confirmed that the levitation performance of steel plates changes depending on the permanent magnet arrangement.

　An AC magnetic suspension system with an LC circuit consisting of an electromagnet and a capacitor has self-stabilization property. Such property is achieved by setting the frequency of the applied voltage to be higher than the resonant frequency of the LC circuit. The AC magnetic suspension system with indirect damping can achieve stable suspension without active control. The previous study indicated that self-stabilization failed due to interferences among the electromagnets in a multiple-degree-of-freedom AC magnetic suspension system. In this paper, the influences of interferences among the electromagnets on floating characteristics are studied experimentally. It is found that the resonant frequencies of LC circuits vary according to the interferences among the electromagnets. It explains why stable suspension could not be achieved. A new apparatus with a larger size and a different structure for reducing the interferences are developed. Stable noncontact suspension is achieved in the apparatus. In addition, the interferences are further reduced by making the resonant frequency of each LC circuits different. It leads to the improvement of floating characteristics.

　Hyperthermia is one of the methods used in combination with medication in cancer treatment. The development of a device with minimal impact on the human body and high therapeutic effect is required for this method, and it is considered necessary to demonstrate the heating effect using a living body. On the other hand, experiments using the human body or animals raise ethical issues, and an electromagnetic phantom that mimics the electrical characteristics of the human body (relative permittivity and conductivity) is useful. In this study, we aimed to develop a liver-equivalent phantom at 8 MHz, which is the frequency of electromagnetic waves often used in hyperthermia and measured the electrical characteristics of mouse liver to determine target values. Furthermore, the electrical characteristics were adjusted by changing the composition ratio of the phantom materials, and a prototype liver phantom was fabricated. The electrical properties of the phantom sufficiently mimicked those of the mouse liver at 8 MHz, with errors of 5.0 % in relative permittivity and 17 % in conductivity.

　To investigate the relationship between spontaneous activity and mental health, the locomotor activity of small laboratory animals is measured. Implantable locomotion meters are used to identify individuals in group housing. The internal primary battery drives the locomotion meter, making it difficult to measure for long time, and the weight causes stress to the animal. A wireless power transmission system is a solution to these problems. As the animal moves erratically, the angle of the locomotion meter changes, and the supply voltage varies. In this study, we measured the change in voltage when the angle of the receiving coil was changed, and we propose and fabricate a transmission coil considering angle change between transmission and reception coils.

　In recent years, the spread of ultra-compact electric vehicles (EVs) is progressing rapidly. These vehicles have advanced characteristics such as compactness, light body, and low environmental impact. However, it is serious problem with interior noise which are road and wind noise from outside. Therefore, we have proposed an active noise control (ANC) system for ultra-compact EVs using boundary vibration by a giant magnetostrictive actuator. In this paper, we conducted two fundamental considerations about the vibration characteristics of the vehicle’s wall surface. In the first experiment, we investigated the output characteristics of the acoustic wave depending on the excitation position of the giant magnetostrictive actuator. In the second experiment, we carried out the experiment about the amount of in-vehicle noise reduction depending on the excitation position of the giant magnetostrictive actuator. As experimental results confirmed that installing the actuator at the excitation point where the sound wave output efficiency is high has a high noise reduction effect.

　Leg support system have been studied to assist people with lower limb disabilities, but the weight is not enough for patients and caregiver. We have developed a lightweight magnetic strain wave gearing with high gear ratio for leg support system. In this paper, we propose dynamic characteristics analysis method for the gear. First, the magnetic force distribution on a flexspline is obtained as magnetic force database, through static magnetic analysis with finite element method. Next, dynamic behavior is calculated through multi flexible body dynamics with the finite element method, the direct solver, and the magnetic force database. The analyzed maximum torque is 3.34 Nm (input rotation angle: stepwise waveform at every 5 deg.). The measured torque is 3.36 Nm (input rotation angle: stepwise waveform at every 5~30 deg.). From these results, the validity of the proposed analysis method was clarified.

　A pediatric ventricular assist device (VAD) using an ultra-compact self-bearing motor, in which a 4-pole levitated impeller is magnetically supported and rotated by two identical 6-slot motor stators has been developed. The outer diameter and height of the motor are 22 mm and 35 mm, respectively. The previously developed motor uses electromagnets that integrate all the windings for magnetic suspension and rotation control. Each winding requires its own power amplifier, which makes the drive system complicated. This paper investigated to reduce the number of wires and the total number of power amplifiers by dividing the integrated winding into two insulated three-phase windings. A maglev VAD prototype with the separated windings was driven in a closed-loop circulation circuit, and indicated non-contact magnetic suspension at the operating condition of the pediatric VAD, although increased total energy input due to the increase in control current according to the reduction in the number of windings was clarified.

　In the purpose of environmental conservation and energy saving, demands for high torque and high energy density drive motors at low speed are increasing, and vernier motors utilizing magnetic gear effect are attracting many attentions. In this paper, the optimal winding methods for a stator module type vernier motor is clarified by using the finite element analysis for several models with different winding schemes in the same module structure. The results show that when two U-shaped cut cores next to each other are wound with the concentrated winding in two slots, the 5th harmonic component increases due to the splitting of the fundamental flux into two-flux paths. This module is effective in vernier motors that rotate using the harmonic flux. Furthermore, a new vernier motor applied this stator-module, which has the optimal winding methods is proposed and its characteristics are presented.

　In order to develop the high efficiency and low loss in transformer, it is essential to reduce iron loss on grain-oriented electrical steel sheet which is one of transformer loss. On the other hand, it is known that the iron loss increases due to the rotating magnetic flux generated at the T-junction of the transformer core, and it is necessary to deal with this problem. A vector magnetic characteristic control technology has been developed that can reduce iron loss under rotating magnetic flux in existing grain-oriented electrical steel sheets. In this paper, we apply the control technology to the existing low iron loss grain oriented electrical steel sheet with a thickness of 0.23 mm, and report the results of verifying the iron loss reduction effect. In addition, the factor of iron loss change was clarified using the two-frequency separation method. Based on the knowledge obtained, we will propose the application of control technology to transformer cores.

　This paper presents the modeling method of conducted noise on AC/DC converter using SiC devices. The common-mode equivalent circuit is derived by leakage current. This equivalent circuit considers multiple resonance points. In addition, the EMI filter for the power supply is modeled and inserted into the derived equivalent circuit for simulation. The usefulness and validity of this method are shown by comparing the simulation results and measurement results after inserting the EMI filter. Then, in order to consider more resonance and improve the precision of the simulation, a genetic algorithm is used to determine the parameters of the equivalent circuit, and the simulation results of the equivalent circuit are shown.

　Recently, reusable rockets are receiving a lot of attention. Liquid hydrogen (LH₂) is often used as a fuel of rockets and turbopumps using it needs high-speed rotation. However, it often brings vibration problems. Oil dampers or rubber dampers cannot be used because LH₂ brings cryogenic environments. Therefore, wire-mesh dampers have been used for rocket dampers by friction force, but these dampers get worn down, so these are not for use of reusable rockets. We propose a multiple-degree-of-freedom eddy current damper for liquid hydrogen turbopumps. The proposed damper can reduce vibration in no mechanical contact using electromagnetic force and doesn’t need any maintenances. In this paper, the structure and principle of this damper are proposed. In addition, the damping performance in cryogenic temperature is evaluated using a three-dimensional finite element method analysis.

　This paper describes a secondary current heating method that allows flexible cooling control to reduce iron loss in laminated stator cores. In the secondary current heating method, the excitation coil generates a magnetic flux, which passes through the laminated stator cores to generate a secondary current. The laminated stator cores are directly heated by this secondary current. We aimed to further improve the magnetic properties by adding a new element to the secondary current heating method. Focusing on the cooling process, we performed heat treatment with flexible cooling control, and compared and investigated the magnetic properties and iron loss. As a result, heat treatment by secondary current heating can reduce iron loss by 31-51 %, but the newly proposed cooling control can further reduce iron loss by up to 6.5 %. The detailed results and discussions are presented in this paper.

　A transcutaneous energy transmission system (TETS) that wirelessly transmits power to a ventricular assist device using electromagnetic induction is sometimes used along with stent graft therapy. However, the electromagnetic field distribution for a stent graft located near the energy transmission coil is unknown. Therefore, in this study, we created a model of the human body, in which a stent and a transcutaneous transformer were simultaneously embedded, for electromagnetic field analysis and numerically calculated the energy transmission efficiency (η), internal electric field, and specific absorption rate (SAR) for transmitting power of 15 W. We observed a 1.7×10^-4 % decrease in η compared to the model without the stent graft insertion. However the SAR of human tissue near the transcutaneous transformer with the highest magnetic field strength remained almost the same. The maximum SAR value for the aortic arch was 1.34 W/kg, which conformed to the guideline value for occupational exposure (10 W/kg) prescribed by the International Commission on Non-lonizing Radiation Protection (ICNIRP).

　It is well known that magnetic properties deteriorate and iron losses increase due to strains induced in motor cores made of electrical steel sheets during those manufacturing process. We have developed a thermal measurement system of the iron loss distributions with a thermography camera in order to clarify the deterioration degree of the magnetic properties depending on different processing methods. In this paper, firstly the iron loss distributions in rectangular specimen of the electrical steel sheet cut with different cutting methods are measured with the thermal measurement system and those results are compared. Two cutting methods are used in this investigation; the wire electric discharge cutting and laser cutting processing. It was clear that iron losses increase due to laser cutting in this paper.

　We are studying the undersea wireless power transfer to undersea probes. One of the problems of the undersea wireless power transfer is that the transmission efficiency decreases due to the misalignment of the receiving coil caused by the tidal currents. By bending the spiral coil used as the receiving coil, the magnetic fluxes, which does not interlink the transmitting and the receiving coil, can link the coils magnetically. The increase of the interlinked fluxes suppresses the decrease in transmission efficiency in case of misalignment. The transmission efficiency using a bent coil is compared with that using a flat coil due to lateral misalignment and angular misalignment of the receiving coil by the finite element simulation software, Femtet. The results show the quantitative decrease in transmission efficiency by the misalignment, and the relatively stable transmission and high transmission efficiency is achieved when the bent coil is used as the receiving coil. In the simulation conditions, the best efficiency is obtained by the 5-degree bend angle receiving coil.

　The products of atmospheric low temperature plasma are highly chemically reactive and have a variety of bioactivities. In this study, we used atmospheric low temperature plasma to evaluate the treatment of bone fractures. In experiment using rats model of bone injury, the tail were incised and then the fifth caudal vertebra were perforated, and the injured area was irradiated with plasma once a day. We performed weekly imaging using CT to evaluate the bone volume increase. The results showed that the plasma irradiated group showed a significant increase in initial bone volume. In the experiment using osteoblasts, when differentiation was induced in the plasma irradiated medium, calcification was observed due to accelerated bone differentiation. These experiments suggest that atmospheric low temperature plasma generated at atmospheric pressure can be used for early recovery of bone fractures.

　We are studying a wireless power transfer to the small mobile robot using piezoelectric elements and electromagnets. The robot can move precisely in the µm scale and can be operated on a magnetic floor. However, the wireless power transfer to the robot equipped with a coil has a problem that the coupling coefficient changes as the robot moves, and the voltage on the secondary side fluctuates, preventing the robot from performing the required precision movement. Therefore, we are studying the suppression of voltage fluctuation transmitted to the secondary side by PT (Parity-Time) symmetry, which automatically operates at the resonance frequency regardless of the coupling coefficient. In this paper, we report the evaluation of secondary side voltage using LTspice.

　In this research, we investigated the characteristic change of the magnetic flux pinning stopping phenomenon due to making the gap between two high-temperature superconductors. In order to investigate the characteristics, we created a superconducting magnetic bearing with a structure that uses the side and top surfaces of the HTS for pinning to use a magnetic flux concentration method. By analyzing the restoring force characteristics of the created bearing in each direction, we verified whether the pinning characteristics would change. As a result of the experiment, by creating a gap between the two superconductors, the pinning property was improved in a specific gap, and the restoring force was increased by the gap. Experiments have shown the usefulness of creating gaps between superconductors.

　Diabetes, one of lifestyle-related diseases, affects more than 500 million people worldwide and is a major problem. Diabetic foot ulcers are foot lesions that develop in patients with diabetic neuropathy and account for 84 % of all lower extremity amputations in diabetic patients. It has been reported that DFU is caused by abnormal vertical and horizontal foot pressure, and intentional gait changes by gait analysis are necessary to reduce the foot pressure. Therefore, gait analysis using vertical and horizontal foot pressure distribution measurement is important for managing DFU. However, no system has been established to simultaneously measure foot pressure distribution in the vertical and horizontal directions. In this study, we investigated, prototyped, and evaluated a three-axis force-sense inductive sensor for the gait analysis application of diabetic patients.

　With global concern for energy and environmental issues, growing interest has been devoted to energy harvesting from the surrounding environment and it has become a research frontier. In particular, vibration energy harvesting is one of the potential technologies to supply the IoT small devices with electricity in the near future. In this study, we focused on the sound vibration and tried to increase its vibration amplitude by using the Helmholtz-type resonator to convert sound vibration to electricity. A prototype of an acoustic energy harvester using acrylic materials and commercially available piezoelectric device was produced, and its power generation properties were studied in detail. As a result, it was found that the peak-to-peak voltage obtained with the sinusoidal sound wave at the frequency of 425 Hz and the sound pressure level of 120 dB reached around 15 V at the maximum. This electricity generation gradually charged a small capacitor and successfully demonstrated the potential of acoustic energy harvesting from the environmental sound sources.