Takayoshi Narita

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.

Basic study on active noise control for considering characteristics of vibration of plate by giant magnetostrictive actuator

In recent years, micro-compact electric vehicles have been developed and actively marketed, and has become popular as a new short-distance transfer mobility tool. While micro-compact electric vehicles do not have generate an engine sound, road and wind noises cause interior noise, and have a large impact on user comfort in the interior space. Recently the use of interior noise reduction by ANC has been used in the automobile industry. In this study, we propose a system whereby a giant magnetostrictive actuator is installed on the front window of a micro-compact electric vehicle to actively cut interface vibration noise, i.e., road noise, transmitted to the interior of the vehicle. In the experiment, we used an enclosure to simulate the interior of a vehicle and investigated the installation position of the giant magnetostrictive actuator to study the vibration characteristics of a window plate.

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.

Effect of a magnetic field from the horizontal direction on a magnetically levitated steel plate: Fundamental consideration on the levitation performance

Thin steel plates are widely used in various industrial products. However, they have problems of flaws in the coating caused by contact support during transport, and deterioration of surface quality. As a solution to these problems, a noncontact transport of steel plates using electromagnetic force has been considered. However, there is a risk that side slipping or dropping 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 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 the Finite Difference Method (FDM). 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. The result shows that the application of a magnetic field in the horizontal direction was confirmed to suppress deflection in the levitated flexible steel plate. In addition, the application of a magnetic field in the horizontal direction improves the levitation stability of steel plates.

Stabilized suspension control strategy at failure of a motor section in a d-q axis current control bearingless motor

This paper presents a stabilized suspension control method when a motor section is unfortunately failed during its operation in the d-q axis current control bearingless motor (d-q BELM). The d-q BELM consists of three sections, in which is divided by every 120° part on its cross section. In each section, the 3-phase winding current is independently controlled by an inverter. Hence, it is possible that the rotor shaft will be supported by the other two sections without mechanical contact even though a section is failed by accidents such as a stator winding short or open, a failure in the inverter. In this paper, a stabilized suspension control strategy at the failure is found and explained in detail. In particular, as the first step, the stabilized control method at no load is focused. The validation of the proposed stabilized control method at the failure is verified by the simulated results using Finite Element (FE) analysis software and the experimental test results using a prototype machine.

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.

Optimization on arrangement of permanent magnets for magnetic levitation system for thin steel plate (fundamental consideration on levitation probability)

For thin steel plates, which are used in many industrial products including those of the automobile industry, we have proposed a magnetic levitation control system and confirmed its realization by means of a digital control experiment. However, the use of a limited number of electromagnets cannot suppress static deflection and high-order-mode elastic vibration, which are characteristics of a flexible magnetic material. To solve this problem, we have proposed a hybrid levitation control system for thin steel plate using the magnetic force generated by permanent magnets, which have no operational costs. In this study, we attempt to determine the optimal gap, placement and number of permanent magnets to reduce the deflection of a thin steel plate under the generated magnetic field. To verify the usefulness of optimal placement of the permanent magnets, experiments concerning vibration were performed on a magnetically levitated thin steel plate.