Shinya Hasegawa

Control of electromagnetic levitation transport of flexible steel plate (fundamental considerations on elastic vibration control under transport)

We have proposed a magnetic levitation control system for flexible steel plates and confirmed its feasibility through a digital control experiment. However, there is a risk that side slipping or the dropping of the plate may occur owing to inertial force, because the levitation control system does not provide any restraints for the direction of travel. Therefore, we have proposed the addition of electromagnetic actuators to control the horizontal motion of a levitated steel plate. In addition, we have reported that it is possible to suppress the elastic vibration of the steel plate in the vertical direction by using the electromagnetic actuators for horizontal positioning. In this paper, the effect of the magnetic field applied from the horizontal direction on the transport performance of a magnetically levitated flexible steel plate is reported.

Study on Horizontal Noncontact Positioning Control for a Magnetically Levitated Thin Steel Plate (Experimental Considerations on Elastic Vibration Control under Transport)

Thin steel plates are widely used in various industrial products. However, they have th e problems of flaws in the coating caused by contact support during transport and the deteriorati on of surface quality. As a solution to these problems, a noncontact transport of steel plates usin g electromagnetic force has been considered. However, there is a risk that side slipping or the dr opping of the plate may occur owing to inertial force because the levitation control system does not provide a restraint for the direction of travel. Therefore, we have proposed the addition of el ectromagnetic actuators to control the horizontal motion of a levitated steel plate. In addition, we have reported that it is possible to suppress the elastic vibration of the steel plate in the vertical direction using the electromagnetic actuators for horizontal positioning. In this paper, the effect of a magnetic field from the horizontal direction on the transport performance of a magnetically levi tated flexible steel plate is reported. We are close to achieving the practical application of a linear motor train that can travel at a speed of 500 km/h. If a linear motor train comprises approximately 16 cars, similarly to the current bullet trains, it will move as if a flexibly moving string material is levitated over a guideway, traveling at an ultrahigh speed without contact with the guideway. We can expect the occurrence of vibration and wave phenomena totally different from those that occur on bullet trains, which run at 350 km/h in contact with the rail via their iron wheels. It is theoretically possible to adjust the apparent rigidity of a train by assuming a string-form multiple-car train to be a superelastic body and applying a tensile force to the traveling connected cars. In a practical case, the tensile force applied to the entire train of connected cars will be adjusted by applying different propulsion powers from the guideway to each car (e.g., different powers around the first and end cars). We aim to change the rigidity of the entire train, in particular, the rigidity of the connecting sections between cars. To this end, we first clarify the mechanism of suppressing the elastic vibration generated when a tensile force is applied to an ultraflexible body in the noncontact method using the technique of controlling the electromagnetic levitation and transport of thin steel plates studied by our research group(1)-(4). The applicability of this mechanism to high- speed motion is also discussed. In this study, an ultrathin steel plate (0.18 mm thick) was magnetically levitated, and we carried out basic experiments to discuss the effect of a horizontal attractive force applied to the stationary levitated steel plate on its elastic vibration, with the aim of obtaining basic findings on various phenomena during motion.

Design and experimental verification of a cascade traveling-wave thermoacoustic amplifier

In this study, we designed and built a prototype of a cascade thermoacoustic amplifier that connects multiple regenerators while satisfying high acoustic impedance at all regenerator positions. To connect the regenerators, the transfer matrix for each component unit, consisting of a regenerator and the adjacent resonators, was analyzed and the eigenvector and the eigenvalue were numerically determined. The experimental results showed that an acoustic power amplification higher than 100 was achieved by the cascade connection of eight regenerators. Furthermore, a high acoustic impedance of approximately six times higher than that of a free-traveling plane wave was realized at all regenerator positions.

Active seat suspension for ultra-compact vehicle (Fundamental consideration on electromyogram when fall from the bump)

In these days automobile industry, the request for ultra-compact electric vehicles has been increasing in Japan. Unlike conventional automobiles, such ultra-compact electric vehicles may frequently travel on roads of poor condition, such as narrow and unpaved roads. These roads have bumps and many small obstacles, and therefore, the ride comfort of the vehicles is expected to deteriorate. Therefore, it is concerned regarding lack of visibility and the head protection functions. We suggest active seat suspension to improve the ride comfort by the disorder road run as a high value-added product. The active seat suspension carried voice coil motor (VCM) which is a kind of a linear motor as actuator. The objective of this study is to inspect utility and the effectiveness of the active seat suspension. In this paper, we focused on the neck electricmyogram and seat acceleration when fall from the bump.

Effect of a magnetic field from the horizontal direction on a magnetically levitated steel plate (fundamental considerations on the shape analysis of ultrathin steel plate)

Thin steel plates are widely used in various industrial products. But there are problems where deterioration of surface quality and metal plating occurred by transporting. As a solution to these problems, a noncontact transport of steel plates using electromagnetic force has been proposed. However, there is a risk that side slipping or the dropping of the plate may occur owing to inertial force because the levitation control system does not provide a restraining for the direction of travel. Therefore we have proposed the addition of electromagnetic actuators to control the horizontal motion of levitated steel plate. In this study, we calculated the shape of steel plate with horizontal attractive force using Finite Difference Method (FDM). It was confirmed that the vertical displacement of the steel plate can be effectively suppressed by using magnetic field in the horizontal direction by performed simulation.

Vehicle interior noise control of ultra-compact electric vehicle (Fundamental consideration using rectangular enclosure)

The demand for noise reduction inside a vehicle has been recently increasing in the pursuit of improved ride comfort. In consideration of requirement of quietness improvement and reduction of weight, an active noise control (ANC) system has been attracting much attention. This method is effective for noise with low frequency. In this study, we propose an ANC system by using the vibration of giant magnetostrictive actuator and we aim to reduce the noise level in an interior of a vehicle using this proposed ANC system. The giant magnetostrictive actuator has a high output that is sufficiently controllable inside a vehicle space and at the same time has high space efficiency. In this paper, the giant magnetostrictive actuator is installed at windshield of the enclosure that act as a vehicle, and the noise reduction effect to ANC were examined as the noise applied to the box from outside.

Numerical study of heat transfer in parallel-plate heat exchangers in thermoacoustic engine

For designing thermoacoustic devices, heat transfer problem of heat exchangers is a key point and is not solved completely yet. In the present study, both computational fluid dynamics (CFD) simulations and numerical analysis based on linear thermoacoustic theory are performed, and heat transfer characteristics, heat fluxes, and Nusselt numbers are investigated from both numerical results. Especially, through parametric studies by linear analysis, the effect of displacement amplitude and thermal penetration depth on heat transfer is discussed. In this simulation, a regenerator is located between hot and cold heat exchangers, and the effect of each channel size is also investigated. Furthermore, simulated results are compared with the conventional heat transfer models for oscillatory flow, and the verifications of those models or simulations are executed. On the other hand, by comparing the CFD results with linear analysis, non-linearity of heat transfer included in thermoacoustic phenomena is also discusse...

Study of Energy Evaluation Control

One of the objectives in control theory is to ensure that a control system converges to a target state in the shortest possible time. To achieve that objective, we studied a control method that combines the Lagrangian, the Hamiltonian, and a bang-bang controller. Referred to as energy evaluation control (EEC), this method evaluates the control state using the Lagrangian, and evolves the control output using the Hamiltonian. Here, the Lagrangian and the Hamiltonian are defined for the deceleration field. The control result from the EEC is fast and robust. Moreover, EEC has the same control strategy as the sliding-mode control, and hence can be incorporated within it.

Noncontact guide system for traveling elastic steel plates (Theoretical study on the shape of traveling steel plate)

In the factory, the continuous thin steel plates are subjected to iron and steel processes are supported by a series of rollers during processes such as plating and rolling. However, because the rollers come in contact with the steel plates, the problem of surface quality deterioration arises. To solve this problem, we developed a non-contact guide system for parts of the steel plate at which its traveling direction changes in high-speed traveling by applying an electromagnetic force from the direction of the edge of the thin steel plate, and experimentally examined the effectiveness of the system. However, the asymmetry traveling steel plate during uncontrolled is not calculated theoretically. In this study, the shape of traveling steel plate is calculated with numerical analysis. It is confirmed that, as we compared analysis result with experiment result, both have similar tendency.

Bending magnetic levitation control for thin steel plate (experimental consideration using sliding mode control)

In conveyance manufacturing process of thin steel plate, since the plate always in contact with the roller, there is problem that the surface quality deteriorates over time. To solve this problem, electromagnetic levitation technologies have been studied. However, when a flexible thin steel plate with a thickness of less than 0.3 mm is to be levitated, levitation control becomes difficult because the thin plates flexure increased. We propose a levitation of an ultrathin steel plate that bent to an extent that does not induce plastic deformation. It has been confirmed that vibrations are suppressed and levitation performance improved. In this study, in order to examine the levitation stability and to compare the levitation performance, bending levitation experiments were carried out on the basis of the optimal control and sliding mode control theory using thin steel plate with a thickness of 0.27 mm.