The yaw acceleration required for circuit driving is determined by the time variation of the yaw rate due to two factors: corner radius and velocity at the center of gravity. Torque vectoring systems have the advantage where the yaw moment can be changed only by the longitudinal force without changing the lateral force of the tires, which greatly affects lateral acceleration. This is expected to improve the both the spinning performance and the orbital performance, which are usually in a trade-off relationship. In this study, we proposed a yaw moment control technology that actively utilized a power unit with a brake system, which was easy to implement in a system, and compared the performance of vehicles equipped with and without the proposed system using the Milliken Research Associates moment method for quasi-steady-state analysis. The performances of lateral acceleration and yaw moment were verified using the same method, and a variable corner radius simulation for circuit driving was used to compare time and performance. The results showed the effectiveness of the proposed system.

Mechanical vibrations adversely affect mechanical components, and in the worst case, lead to serious accidents by breaking themselves. To suppress vibrations, various studies have been conducted on vibration isolation, suppression, and resistance. In addition, technologies to actively suppress vibration have been rapidly developed in recent years, and it has been reported that vibrations can be suppressed with higher performance. However, these studies have been conducted mostly for low-order systems, and few studies have employed control models that consider the complex vibration characteristics of multi-degree-of-freedom (DOF) systems. This study is a basic study that establishes a control model for complex control systems, and the vibration characteristics of a 2-DOF system are calculated using the vibration analysis of a multi-DOF system. Furthermore, the vibration suppression performance of the 2-DOF system is investigated by performing vibration experiments.

Flexible steel plates are generally transported by rollers; however, the contact between the rollers and the steel plate degrades the surface quality of the plate. To solve this problem, noncontact transportation of steel plates using electromagnetic force has been proposed. However, ultrathin flexible steel plates can easily fall owing to deflection. A magnetic levitation system using electromagnets installed in the horizontal direction has also been proposed to improve the levitation performance of a conventional system. However, it is difficult to control vibrations with such a system because flexible steel plates are elastically deformed into complex shapes by gravity. Therefore, an electromagnetic levitation system was proposed, wherein electromagnets were installed near the edge of the steel plate such that it could be controlled with noncontact grip, such as by allowing one side of the steel plate to hang. This system is expected to improve levitation stability because the moment of inertia increases with vertical levitation and simplifies the control system. In addition, this system actively uses gravity acting on a steel plate to decrease its deflection. The use of gravity to suppress deflection is novel. In this study, the feasibility of magnetic levitation using the proposed system was investigated using magnetic field analysis. Its usefulness was investigated experimentally using a constructed magnetic levitation system. In addition, it was found that a magnetic levitation system that maintains the standing position generates a peculiar vibration.

In recent years, further improvements in the performance of internal combustion engines to reduce environmental burden have been demanded. The combustion state of an engine is affected by the parameters of the dynamic valve system, such as the opening/closing timing and the lift of the intake and exhaust valves. Therefore, we investigate an electromagnetic valve-drive system in this study. Two models are created to improve the magnetic circuit and increase thrust. To investigate the thrust characteristics of these actuators, an electromagnetic field analysis is conducted using the finite element method. Meanwhile, to investigate the effect of the yoke material on the thrust, an electromagnetic field analysis is performed based on materials with different saturation magnetic flux densities and magnetic permeabilities.

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.