The Asia Pacific Symposium of Applied Electromagnetics and Mechanics 2014 (APSAEM 2014) is the eighth symposium devoted to topics on electromagnetic phenomena, both on low and high frequencies, and its applications in electrical, mechanical, communication systems and medical applications. It was first started in 2000 at Adelaide, Australia and then at Kanazawa, Japan in 2001, followed by Auckland, New Zealand (2004), Sydney, Australia (2006), Bangkok, Thailand (2008), Kuala Lumpur, Malaysia (2010), Ho Chi Minh City, Vietnam (2012). The symposium is one of a series of events sponsored by the Japanese Society of Applied Electromagnetics and Mechanics (JSAEM). APSAEM 2014 is organized by the Graduate Institute of Biomedical Engineering, National Chung Hsing University (NCHU), Taiwan and co-organized by the Japanese Society of Applied Electromagnetics and Mechanics (JSAEM). The symposium provides an excellent biennial opportunity for sharing knowledge, experience and creative ideas among academia from various universities, research institutes, as well as from industries in the area of applied electromagnetic and mechanics, such as the following: Computational electromagnetics, Inverse problems, Characterization and modeling of electromagnetic materials, Magnetic sensors and measurement, Nondestructive testing, Applications of electromagnetic phenomena, MEMS, Electromagnetic and electromechanical devices and systems, Electromagnetic actuator and applications of permanent magnet, Applications in power, electronics, and control systems, Power electronics and drive systems, Electromagnetic environment and control, Electromagnetic compatibility(EMC), Applications of electromagnetic to medical treatments, Microwaves and antennas, terahertz applications, Applications in telecommunication, Electromagnetics and electromechanical education, and Magnetic Fluids. NCHU is one of the top universities in Taiwan and located in Taichung City, Taiwan. Taichung, in a key central Taiwan location, plays an essential role in both Taiwan's economic development and transportation systems. Surrounded by the mountains and sea, it possesses the precious assets of rich cultures of numerous townships and districts. APSAEM 2014 has received more than 100 papers from international and local participants from 9 Asia Pacific and European countries and assembled authoritative keynote speeches, technical presentations, and poster sessions among participants from universities, research institutes and industries for their further collaborations in the future. Out of those submitted papers, 35 are accepted to be published in the Journal of the Japan Society of Applied Electromagnetics and Mechanics. Next issue of the journal is the special issue of APSAEM2014. Here, as the chairman of the conference, I would like to express my appreciation to participants of the conference and reviewers of the papers. Without your effort, the conference and the special issue cannot be done. Finally, I would like to remind that the next symposium will take place in Indonesia in 2016.
This paper presents vector magnetic characteristic analysis by using the complex E&S modelling taking account of stress effect. According to the past researches, we have evaluated the magnetic field strength H vector under controlled stresses and sinusoidal magnetic flux density waveforms. However, it is impossible to control the magnetic flux density B in actually magnetized motor cores. Therefore, it is necessary to know the relationships between B- and H-vector under the controlled stress and the non-controlled magnetic flux conditions. In this paper, we report the measured and calculated relationship between B- and H-vector under stressed conditions and given sinusoidal voltage conditions. The trajectories and parameters of the B- and H-vector under stress, calculated by using the Stress-Complex E&S (SCE&S) modeling, were agreed well with those of the measured B- and H-vector.
The usefulness of a novel simplified time periodic-explicit error correction method for the practical synchronous motors is clarified quantitatively. The method can improve the convergence behavior to the steady state in the analysis of electromagnetic equipment including the DC magnetic field. Furthermore, in order to apply the magnetic field analysis coupled with the electric circuit, the novel method is extended. In addition, the technique, which can improve the convergence to the steady state using the time and spatial periodicity in the analysis of synchronous motors, is proposed, and the usefulness is clarified.
Eddy-current (EC) displacement sensors are used in devices for measuring the shaft vibration of turbines. An EC displacement sensor is composed of a coil, a coaxial cable and an impedance / output voltage (Z /V) converter. The state of coaxial cable may change according to the situation, which is problematic because the sensitivity of the eddy-current (EC) displacement sensor changes when the state of the coaxial cable changes. The output voltage and sensitivity depend on the impedance of the EC displacement sensor because it is used as part of an oscillation circuit in impedance/voltage (Z/ V) converter. The impedance due to torsion of the coaxial cable of the EC displacement sensor due to frequency was measured. In addition, the impedance, change including the oscillation circuit of the EC displacement sensor due to torsion of coaxial cable, was measured. The oscillation frequency was optimized such that a reduction in change of sensitivity is possible.
The remanence remaining in a volcanic rock is one of important measurement data in geophysics field. The sample of a rock has the remnant magnetization up to 10-9 T. Generally the remote magnetic fields measured by SQUID gradiometer presume the remanence of a rock as a sample. We propose a new methodology by measuring a magnetic field inside a cylindrical hole in the rotating sample. We could develop the simple measurement without shield system and high sensitivity sensor. The paper described the measurement system and the measured results of the rock. We could measure the remanence of a volcanic stone quarried from the volcanic rocks at Mt.Aso, Japan.
To prevent a serious accident by the metal degradation of a structure made of iron-based structural materials, we have already proposed some fatigue evaluation methods for various iron-based structural materials. One of these is a residual magnetization method that uses a thin-film flux-gate magnetic sensor. This method is called the perpendicular residual magnetization method. This fatigue evaluation method had a good correlation between the magnetic sensor output signal and the amount of plane bending fatigue damage in the iron-based structural materials. However, we have not yet evaluated the pulsating tension fatigue damage of iron-based structural material such as the austenitic stainless steels using this method. In this paper, we report the evaluation results of a pulsating tension fatigue damage accumulation in austenitic stainless steels (SUS316 and SUS316L) using the perpendicular residual magnetization method. From our experiment, the maximum value of the Z component residual leakage magnetic flux density clearly depends on the magnitude of pulsating tension and the number of stress cycles.
This paper describes a liftoff characteristic on backside defect searching by low frequency excitation of the ∞ coil. The low frequency ∞ coil excitation confronts to a noise problem in the practical experiments. To overcome this difficulty, this paper employs a Fourier transform signal processing method to remove the higher frequency noise components compared to the excitation one. Thus, we have succeeded in enhancing the S/N ratio and detecting the signals caused by the backside defects of the targets. As a result, we have elucidated that a liftoff characteristic of the backside defect searching is clarified by employing the low frequency excitation to our ∞ coil. Experimental as well as numerical verification along with intensive three-dimensional finite element method have been carried out to confirm our results.
This paper presents the effect of stress-relief annealing on magnetic properties using an induced current heat-ing(ICH) method in order to reduce the residual stress in the motor cores. The magnetic properties of a motor core annealed using the ICH method were first compared with those of a core annealed using a conventional electric furnace. When the hold time in each method was the same, the magnetic properties using the ICH method were improved over those using the EF method. The effects of varying the annealing temperature and time for the ICH process were then investigated. It was found that the values of the maximum permeability increased and the hys-teresis loss decreased with increasing annealing temperature and time. The total time of the stress-relief annealing could be achieved in a short period of about one hour.
This paper presents a new structure of bone conduction speaker. It is smaller than the conventional structure by removing an extra space. The magnetic path of this structure is not wasteful because the coil case is attached a cover and this structure uses the magnetic material as the vibrating plate. This structure operates by flowing the audio current into the voice coil. That reason is the change of magnetic attractive force between the magnetic pole of yoke and magnet. The authors revealed various characteristics of this structure by the electromagnetic field analysis and structural analysis by using the 3-dimensional finite element method (3D-FEM). As the result of electromagnetic analysis, the leakage flux of this structure is lower than the conventional structure by 55.2 %. As the result of structural analysis, the sound pressure level (SPL) of this structure is higher than the conventional structure by 12.6 %. Consequently, the performance of this structure is improved.
Ni-Mn-Ga magnetic shape memory alloy is a prospective material for actuation because it exhibits large magnetic field induced strain at high frequency. However, it also displays strong hysteresis in the strain-magnetic field curve, and the hysteresis property makes it difficult to control the strain in the actuator use. This paper describes the analysis method for the linear actuator made from Ni-Mn-Ga magnetic shape memory alloy in order to predict the magnetic field induced strain. In the proposed method, the coupled analysis of finite element method is used with the play hysteresis operator. The results of the simulation are compared with the measurements on a prototype of the actuator.
Magnetic flux leakage from an AC adapter or a notebook PC can be recovered by using a coil. However, because the magnetic flux that leaks out is very small, the power that can be collected by a coil is small. As a result, the quality factor of the coil must be increased to increase the power that can be collected by the coil. The use of magnetoplated wire (MPW) to from the coil can reduce the resistance due to the proximity effect in comparison with the use of copper wire (COW). MPW is a COW that has a circumference that is plated with a magnetic thin film. In this paper, we investigate the energy harvesting by a coil consisting of MPW. We used a coil with an outer diameter of 9.9 mm and 300 turns. The quality factor of the leakage flux recovery coil using COW and MPW at a frequency of f = 250 kHz was 119 and 135, respectively, and it is increase in 13.4% by using MPW.
A lot of studies on reducing cogging torque of permanent magnet machines have so far been carried out. However, the most of them are objected for the radial-gap type machines, which have wide application in various fields. In this study, the various techniques of reduction of cogging torque that can be used in rotor part of an axial-gap generator are examined numerically by using the three-dimensional finite element method. It is shown that the reduction of the cogging torque is difficult in the axial-gap type machine rather than the common radial-gap machine. The analyzed results with the three-dimensional finite element method are compared with ones of a reference model of the axial-gap permanent magnet machine, and the improvements are demonstrated.
This research investigates the peel force of electrostatic adhesion, or electroadhesion, based on the Kendall model. In the other adhesive materials such as adhesive tapes, the adhesive energy density is decided only by the property of the bonding interface, and its value can only be acquired by experiments. In the electrostatic adhesion, however, because the adhesive energy is generated by electric field, it can be calculated as electric energy and controlled by changing the voltage or the layout of the electrodes. Due to the absence of interface bond in electrostatic adhesion, the adhesive energy density does not change with the peel velocity, while other types of adhesion such as adhesive tapes do. As for electrostatic crawler-type climbing robots, the paper discusses solutions to strengthen the peel torque of the robot. The paper shows that the pretension force has an optimal value for maximum peel torque.
It is necessary to reduce the inclination of the objective lens in high-density optical disc drives to improve recording and reading characteristics. We have developed a new objective lens actuator that is equipped with an optical disc drive and that moves the objective lens electromagnetically. This actuator has a configuration in which the tracking coils and magnets on one side of the actuator are arranged in reverse to those on the other side to reduce the rolling tilt of the objective lens. The rolling moments generated in the tracking coils on both sides of the actuator occur opposite to each other, and the resulting rolling moment is reduced. We confirmed through numerical analysis and experiments that the rolling tilt amplitude at the rolling resonance of the developed actuator was 90% less than that of the value for a conventional actuator.
The Malaysia's average of oil palm production have been increasing every year since last two decades. This is due to the increase global demands. Therefore, it is an urgent need to improve the harvesting productivity in the field. For such reasons, a harvesting machine had been developed to overcome this problem. This harvesting machine consists of DC motor and powered by electrical generator. Due to limitation of space and weight, Double Stator Permanent Magnet Generator (DSPMG) topology is being used. DSPMG has an advantage in producing high power density compared to conventional generator due to its large coil area. Sudden changes of current can be seen as the load changes when the harvester operates. Obviously, the generator performance needs to be studied. Therefore, this paper discusses on the performance of DSPMG by evaluating the power mapping characteristic. From the power mapping characteristic, the overall view of generator performance can be presented. The DSPMG shows that the highest output power (180W) can be achieved at load impedance of 10 Ω.
This paper presents performance comparison between spoke type and hollow-rotor permanent magnet generator (PMG) that could be used for low speed energy harvesting application. In this application, the requirement for such generator would be higher power density due to the limitation of space, volume and weight. The drawback of spoke type PMG is the flux leakage at end of the permanent magnet that embedded inside the rotor. Meanwhile, the hollow-rotor PMG introduces a hollow segment that obstructs the flux from flowing at the end of the permanent magnet. This new arrangement maximizes the energy that contributes by the permanent magnet. The objective of this paper is to compare the performance of both PMG in term of output power and speed at various load condition. In this research finite element analysis is used for modelling and simulating the PMG performance. For final comparison, power density is used for evaluating the best performance and the result shows that the hollow-rotor topology has higher power density compared to spoke type PMG. In the end, this paper provides an overview about the advantage of hollow-rotor topology that could be used for small energy harvesting application.
The dynamic characteristics of a proposed two degree-of-freedom (DoF) actuator under amplitude feedback control are investigated in this paper. The feature of our proposed two DoF resonant actuator is that movement in the x- and z- axes can be independently controlled by vector control. Two controllers: a PID controller and a proxy-based sliding mode (PSM) controller were compared for amplitude feedback control. A simulation model using finite element method (FEM) and MATLAB/Simlink is made, and the dynamic characteristics of the actuator under feedback control are calculated. Moreover, measurements on a prototype are conducted to show the validity of the simulation results.
In this paper, we propose a new magnetic movement converter for linear oscillatory actuators. The proposed magnetic movement converter can convert a rotational motion into a linear motion, and reduce the load torque on a rotor, and the armature is oscillated with fewer harmonics. First, the basic construction and the operation principle are described. Next, we confirm its characteristics through FEM analysis and measurement on prototypes.
This paper presents the shape optimization of magnet and flux barriers in the interior permanent magnet synchronous motor (IPMSM). Authors use the polygon model method with genetic programming (GP) by the two-dimensional finite element method (2D-FEM). In this method, the analysis model of IPMSM is regarded as a tree structure. This method optimizes a shape by operating tree structures with GP. The tree structure of this method is possible to express every shape. Therefore, this method can obtain an optimal shape without being bound by a stereotype. The purpose is the investigation of shape design of magnet and flux barriers to improve the electromagnetic characteristics. Additionally, authors take into consideration about complexity of shape and volume of magnet.
Springs are used for various purposes, particularly for vibration control and the removal of machines. However, the use of a spring generates a high amplitude at the resonance point; therefore, it is difficult to suppress vibrations from all frequency bands. To solve this issue, a variable rate spring is developed, which is a magnetic spring. This variable rate spring can change its spring constant. An experiment is carried out by placing compression and magnetic springs along the same axis to miniaturize the experimental device. Basically, the natural frequency of the vibration system fluctuates with changes in the spring constant. As a result, the problem can effectively be resolved by changing the resonance point and suppressing the vibration. The variable rate spring consists of magnetic and compression springs; the utility of the spring is verified by an experiment and a simulation.
This paper designs the rotor structure of a permanent magnet (PM) synchronous generator by a topology optimization method. The implemented optimization method is the Genetic algorithm coupling the concept of cluster of materials and a cleaning procedure, and then it assumes four hexahedron PMs similar to the rotor shapes obtained by the proposed method for reasons of manufacturing ease. This paper manufactures the optimized rotor structure, which has a high flux linkage. Experimental results clarify that the voltage regulation is improved and that the efficiency is improved.
This paper proposes a feedback control method for a Linear Resonant Actuator (LRA), in which an external load can be estimated using two signals of the back-EMF. Using this estimated load, it becomes possible to reduce the decrease in amplitude of LRAs when the external load suddenly increased. The effectiveness of this method was verified through FEM analysis and measurements.
In this paper, we proposed a compact electromagnetic generator structure with high instantaneous power output which can be used for energy harvester device. It used the negative magnetic spring characteristics to transform the human operation to the instantaneous electrical energy. With a radio module load, the induced maximal voltage of the prototype device is 4.82 V, the maximal current is 53 mA, and the instantaneous power is about 250mW. Under our experiment, we successfully drove Enocean's PTM330 radio module.
The purpose of this paper is to present the possibility to combine a Stirling engine and a DC motor as a hybrid system. The Stirling engine is a heat engine that can be used with various kind of fuel. The main disadvantages of the engine are the low starting torque and the low engine power. This make the engine cannot start by itself. In this paper we propose how to combine the Stirling engine with a DC motor to solve the problem. Then, we use the DC motor at the starting phase or in the situation that the Stirling engine cannot work properly. This hybrid system consists of a Stirling engine, a DC motor, a driving gear box, a power transmission unit, a battery and a microcontroller. The driving engine can be switched by the microcontroller on the power transmission unit. The hybrid system is tested in a real small train system model. The results show that the system has the maximum speed of 20.4 rpm and the efficiency is about 21.22 % of the injection power.
This paper proposed a battery charging system for intermittent generation from a synchronous generator with a novel Maximum Power Point Tracking (MPPT) control method. Analyzing the generation with boost chopper by the state space averaging method, the internal voltage of the generator, the output voltage and the resistance of the output of the boost chopper can be estimated by with only single current sensor. Even though the intermittent generation, the proposed the battery charging system is able to charge the battery constantly because of a bi-directional DC/DC converter and an Electric Double-Layer Capacitor (EDLC). The basic principle of the proposed MPPT control method and the proposed charging system are discussed, and then confirmed by digital computer simulation using PLECS. The simulation results reveal that the proposed MPPT controller controls the maximum power point and the proposed charging system is able to charge the battery constantly.
This paper presents a novel electrical power supply system for an isolated system using a matrix converter (MC). MCs are able to convert AC to AC power directly without DC link capacitors. In this paper the MC is used as the main conversion equipment, because arbitrary output, AC to AC and AC to DC, are obtained to use adequate switching pattern. In this paper one AC output with constant frequency, and two DC output for battery storages system is explained, as an example. Direct duty ratio pulse width modulation (DDPWM) is selected to achieve the desired output. In addition, fictitious reference iterative tuning (FRIT) is employed to design the controller gains. The validity of the proposed method is shown using MATLAB/Simulink simulation.
Cell manipulation and operation have played important roles in modern biotechnology, hence a number of researchers have developed them during the past decades. In this paper we introduce two techniques based on dielectrophoresis (DEP) and optical tweezers: Distinction between viable cells and non-viable cells using DEP, Manipulating cells captured by positive DEP (pDEP) using optical tweezers. And then we suggest a system combined both DEP and optical tweezers, that would be a useful tool in biotechnology. This system will be useful to perform cell operation and other applications in biotechnology.
We developed an actively mode-locked fiber laser that can generate 295 fs pulses at 9.188 MHz repetition rate. We built up a laser-induced cell fusion, in which the developed femtosecond laser was used as the laser source for both optical tweezers mode and laser scalpel mode, and thus improving cost-effectiveness. The cell fusion system also used a transparent dielectrophoresis chip as the specimen stage to create and manipulate the pearl chain of two or multiple cells for facilitating the cell fusion processes. We successfully developed the first optical tweezers using femtosecond fiber laser operating at 1530 nm, which can trap and transport cells effectively. With this developed system, we obtained the laser-induced fusion of red cabbage protoplasts. We also proposed a experimental cell fusion procedure which allows precisely selective cell fusion at the single-cell level. Therefore, the developed system would benefit basic research in biotechnology and biomedicine.
Induction heating type hyperthermia treatment, as one of cancer therapies, needs both high magnetic fields (> 2 mT) and a few hundred kHz inside of a body. We proposed the double-pancake type coil system sandwiching human body. The proposed exciting coils can generate magnetic fields with both magnitude and frequency required to a medical treatment, and also can adjust the distance between two flat coils according to the bodily proportions of a patient. In order to make magnetic fields inside a body further increase, a back yoke as magnetic materials is added to both coils. The paper discussed magnetic- and electrical-circuit characteristics of the exciting coil with a back yoke.
In this paper, dielectrophoresis tweezers using metal coated chemically etched fiber was proposed for cell manipulation and isolation. We proposed a simple and low cost dielectrophoretic device for picking out and relocating single target cells. The device consists of metal coated chemically etched fibers and an AC signal generator. It does not require microfabrication technologies or sophisticated electronics. From experimental results, it was found that our proposed dielectrophoretic manipulator could discriminate between live and dead cells. We also could see the cell reproduction of yeast cells trapped and isolated using our proposed dielectrophoresis tweezers.
Dielectrophoretic impedance measurement (DEPIM) method has recently attracted attention because the method is simple and immediately. We demonstrated that the impedance between the electrodes with trapped cell has thermal property and measured cellular temperature by the impedance change even if the number of trapped cells did not change. However, this result was not observed when cells were not trapped between the electrodes. In summary, the cellular temperature could be measured by observing the change in shunt voltage. In this study, we developed cellular temperature measurement system and it was expected to be used in biosensor application. In the future, we want to measure single cellular temperature with isolation by optical tweezers.
Damping force of a damper utilizing MR fluids containing needle-like particles is investigated experimentally. In this paper, μm-size carbonyl iron particles (average diameter is about 1.2 μm), and needle-like iron particles (long axis is 100 nm and aspect ratio is 4.0) or non-magnetic needle-like hematite particles (long axis is 194 nm and aspect ratio is 8.3) were mixed in the base fluid. The damping force becomes larger with the mixing ratio of the needle-like particles (iron and hematite) larger even in the absence of the magnetic field. If magnetic field is applied, the damping force becomes larger and the flow characteristic of fluids is changed.
Effect of magnetic field direction on forced convective heat transfer of magnetic fluid flow in a rectangular duct was investigated experimentally. Magnetic fields were applied to magnetic fluid flow in three directions, which were an axial direction, a parallel direction and a vertical direction against the heat transfer direction. Reynolds numbers based on hydraulic diameter and bulk mean velocity were set at about 980 for laminar flow and about 6700 for turbulent flow. In the case of laminar flow, heat transfer was enhanced in the vertical direction and slightly enhanced in the axial direction, but hardly changed in the parallel direction. In contrast, in the case of turbulent flow, heat transfer was suppressed in all directions. The suppression level in vertical and parallel direction is similar, but the suppression in axial direction is much weaker than those in other directions. Moreover, in order to discuss the heat transfer characteristics, the velocity distribution was also measured by an ultrasonic technique.
In our works, a human skin scratching monitoring system has been developed in order to evaluate the itch sensation. For the purpose, finger posture is one of important information. In order to obtain the finger posture, a simple sensor system using a polymer sensor is proposed. The polymer sensor is composed of ionic liquid and solid polymer electrolyte. The sensor output is corresponding to the deformed curvature in sensor. Firstly, frequency response of the polymer sensor is investigated. It was found that the sensor output slightly decreases with the increase in the deformation frequency and that hysteresis loop enlarges with increase of the frequency. Next, a scratch motion sensor is fabricated. It has a simple structure that the polymer sensor is attached on the finger joint by using a net bandage. Then, Relationship between finger bending angle and sensor output is investigated. From the comparison between sensor output and the bending angle, it is observed that sensor output has a good agreement with the finger bending angle. As a result, it is found that the polymer sensor is available to measure the finger bending during scratching.
Damping force of the damper using a particle assemblage depends on installation angle of the damping due to gravity acting on the particles and existence of space in the container of the damper. In order to suppress such dependency of installation angle, magnetic particles are used as particle assemblage in the damper and magnetic field is applied by using two electromagnets or permanent magnets. It is shown that the effect of installation angle on the damping force is reduced by using applying magnetic field.
In recent years, minimally invasive surgery is progressing. As one of the minimally invasive surgery, there is endoscopic surgery. It reduces burden of the patient. However, the burden of the operator increases. So, to purpose of reducing the burden of the surgeon, we have developed a surgical assisted system. This system is composed of the supporting device and the robotics forceps. In this research, we describe the development of the supporting device. In this paper, to development of the supporting device, we describe the design of a sensor detecting the operation force of surgeon. We evaluate the characteristics of the sensor designed. The results, we describe the improvement plan and problems.
Eddy-current displacement sensors (EC displacement sensor) are used in a variety of industries, such as detection of shaft vibration for power generation turbine. An EC displacement sensor is composed of a coil, a coaxial cable and impedance / output voltage (Z/V) converter. Z/V converter composed of Colpitts oscillation circuit and rectifier circuit. In addition, impedance of EC displacement sensor probe is used for a part of Colpitts oscillation circuit. If output and oscillation voltage of a self-oscillation circuit and impedance of EC displacement sensor probe are calculated, design of EC displacement sensor of a self-excitation circuit becomes facilitated. In this paper, impedance of the EC displacement sensor probe by theory of Dodd was calculated. Furthermore, oscillation voltage was calculated by simulation software. Then, measured and calculated values were consistent. As a result, design of circuits of EC displacement sensor can become easy.