Search

As automated driving has not yet been established, on narrow roads where there is no separation between pedestrians and vehicles, it is essential to switch to manual driving. However, when the driver turns the steering wheel from one hand to another on narrow roads, it causes steering burdens and operational errors if the steering feel or burden is not proper. Thus, this study aims to construct an active steering wheel system that provides an appropriate steering feel or burden by controlling the steering reaction torque, driving position and steering gear ratio for each driver. In this paper, we focused on and examined the driving position among these. A two-dimensional steering model that considers the size of the arms for each driver was established to evaluate steering burden. In addition, a basic study was conducted on the appropriate driving position. Then, based on the joint movements and angles calculation, the appropriate driving position that considers the size of the arms was studied by evaluating the joint power. As a result, it was found that if the steering wheel position is too close to the driver, the amount of joint movement increases, and if it is too far away, the joint movement decreases. Therefore, it was found that the appropriate steering wheel position for each driver's arm length can be considered by using the joint power. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

In recent years, ultra-compact electric vehicles have gained increasing interest. These vehicles can easily make turns owing to their compactness, and they have a low impact on the environment. However, exterior road and wind noises have a large impact on occupant comfort in the interior space because an electric motor is used instead of an internal combustion engine. Therefore, an active noise control system using control sound or masking for ultra-compact electric vehicles was studied. To select the sound used for masking, a sound containing 1/f fluctuation, which has a relaxing effect on humans, was investigated. In the study of 1/f fluctuations, various analysis methods for comfort evaluation are used. However, a method of detecting sounds including 1/f fluctuations has not been established and clarified. Thus, a basic study of 1/f fluctuations was performed to select the sound to be used for the masker. Furthermore, brain waves of participants were measured in cases in which participants heard sounds including or not 1/f fluctuation. The results revealed that sounds including 1/f fluctuation of amplitude and frequency helped participants to relax. [ABSTRACT FROM AUTHOR]

An ultra-compact electric mobility vehicle cannot be equipped with power steering, and the physical burden is large. Therefore, we are continuously researching steering support for an ultra-compact electric mobility vehicle equipped with a steer-by-wire system (SBWS). The SBWS has not been widely diffused because the steering and front wheels are connected only to electric signals and do not have a high redundancy level. However, the advantage of an SBWS is that the steering reaction torque felt through the steering wheel can be controlled freely. We investigated an active steering wheel system (ASWS) that can control an appropriate steering feeling for each driver by being equipped with SBWS and evaluating the steering burden of each driver. So far, research on the SBWS has been considered to improve operability by transmitting road information and feeding back vehicle motion, however few research on an SBWS considers the physical and mental burden on the driver. In this study, we conducted a fundamental analysis of the effect of the steering reaction torque on the steering burden, focusing on the operating direction of the steering wheel. [ABSTRACT FROM AUTHOR]

In the production line of thin steel plates, contact conveyance by rollers causes deterioration in the surface quality of the plates. To solve this problem, our research group has been continuously investigating the optimal placement of permanent magnets in hybrid magnetic levitation systems. In this study, when a thin steel sheet was magnetically levitated, the effect of the horizontal electromagnet position on the gap between the steel sheet and the permanent magnet was investigated through a permanent magnet configuration optimized using a genetic algorithm. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Recently, demand for thin steel plates has increased. In the manufacturing of thin steel plates, surface quality deterioration due to contact between the rollers and steel plate involved is problematic. We are investigating magnetic levitation conveyance to propose a noncontact conveyance system using electromagnets. However, the magnetic levitation of thin steel plates is unstable because of the deflection in the range where the electromagnetic force is not affected. Therefore, to improve the levitation stability, we are investigating a bending magnetic levitation system in which a thin steel plate is bent during magnetic levitation but not deformed plastically. In this study, a dynamic analysis using the finite difference method is performed to understand the behavior of a thin steel plate during magnetic levitation. In the dynamic analysis, vibration is evaluated based on the displacement standard deviation. The dynamic simulation visualizes the dynamic behavior of a levitated flexible steel plate. [ABSTRACT FROM AUTHOR]

Providing a comfortable sound for users is an important factor for high-value products. Therefore, many studies have investigated pleasant sound levels for developing and manufacturing new products. Notably, sounds containing 1/f fluctuations provide a relaxing effect in humans. There are many studies on the influence of sound signals, including 1/f fluctuations; however, the verification of fluctuations, including sound signals, has not been performed. In this study on fluctuation, the discrete Fourier transform was used to directly calculate the time of the sound signal. We evaluated the duration of music and the 1/f fluctuation via the discrete Fourier transform using the time history of the music data. Furthermore, we investigated the relaxation effect of music containing a 1/f fluctuation. We determined a person's comfort according to the difference in the calculated fluctuation coefficient by subjectively evaluating the comfort felt by people when listening to music with two different fluctuation coefficients, and we examined the improvement in the fluctuation coefficient and human comfort. [ABSTRACT FROM AUTHOR]

We investigated whether there is a correlation between the comfort felt by occupants and the comfort estimated from biological information obtained by experiments to improve the ride quality of an ultra-compact vehicle. A single frequency in the vertical direction can help to estimate occupant comfort. However, we hypothesized that the study of a single frequency was insufficient. We oscillated the occupants with vibrations containing multiple vibration frequencies and obtained biometric information. The vibration frequency was set based on the difference in ride quality felt by humans. Biometric information was obtained using a cerebral hemodynamic meter and electrocardiogram. Acquiring multiple types of biometric information helps to more accurately estimate the psychological state. After the experiment, we obtained a subjective evaluation of comfort against vibrations using the visual analog scale (VAS). The biometric information obtained by the experiment was cluster-analyzed, and experimental participants with similar characteristics of the biometric information were grouped. Multiple regression analysis was performed based on the values of the typical biometric information of the cluster. Comfort was estimated from biometric information using multiple regression analysis. A correlation was confirmed between measured and estimated VAS scores. [ABSTRACT FROM AUTHOR]

A hybrid vehicle is a vehicle with two or more power sources. We propose a hybrid system in which the engine torque converted by the transmission is combined with an electric motor torque. The proposed system reduces transmission because engine torque only acts during transmission. Furthermore, the proposed hybrid system's simple structure uses lightweight chains and sprockets that can be laid out in various ways. The realization of the proposed hybrid system requires independent control algorithms for the two power systems, engine and electric motor, that take into consideration the state of the vehicle and the driver's input; this system can be assumed to be a servo model system with multiple inputs and outputs and analyzed to obtain the optimal operation algorithm. To apply these controls to race cars, which are required to be fast, it is necessary to obtain the reference input, which is the optimal velocity and yaw angle while traveling the course of the servo system, and simulations of the competition track must be carried out. Therefore, the dynamic performance of the hybrid system was investigated by calculating the lap times on a given circuit using a quasi-steady-state method with low computational load and high prediction accuracy. In this study, the effects of changing the electric motor and final gear ratios on the driving performance of a rear-wheel-drive parallel hybrid system for optimization were investigated. The simulation results show that not only can the optimum settings be obtained by changing the final and electric motor reduction ratios on the evaluation circuit, but also that the optimum values vary across different speed ranges on different circuits. [ABSTRACT FROM AUTHOR]

In ultra-compact electric vehicles, the satisfactory installation of an assist mechanism for steering operation is difficult. To address this problem, in this paper, we propose an active steering wheel system in which the steering wheel and tires are electrically connected, without a mechanical connection. Furthermore, in ultra-compact mobility vehicles where the driving position is restricted, steering burden is likely to occur depending on the physique of the driver. However, whether the effects of the steering reaction torque and the amount of steering increase the burden on the driver in such vehicles has not yet been clarified. Therefore, in this study, we developed an upper limb burden model using inverse kinematics and muscle activity to investigate the burden of steering on the driver by considering the driver physique. [ABSTRACT FROM AUTHOR]

The grasping and conveying of an object by utilizing the frictional force generated by contact are performed during various steps in the process of manufacturing industrial products. Deterioration of the surface quality due to these contacts is a problem. A noncontact way to transport steel plates using electromagnetic force has been proposed as a solution to these problems. In such applications to date, electromagnets are installed in the vertical direction. However, if the steel plate is thin and lacks sufficient flexural rigidity, it is difficult to exert enough suspension force to levitate the entire steel plate. To solve this problem, we propose an edge-supported electromagnetic levitation system suitable for flexible steel plates using electromagnets installed in the horizontal direction. In this paper, we report on levitation experiments to verify the effectiveness of the proposed system and discuss characteristics of the horizontal positioning of electromagnets and levitation suspension. [ABSTRACT FROM AUTHOR]

Thin steel plates are widely used in various industrial products. However, because of the deterioration of surface quality and metal plating that occurs during transport, some problems exist. As a solution to these problems, a noncontact transport of steel plate using electromagnetic force has been proposed. However, side slip or the dropping of the plate may occur. Therefore, we proposed the addition of electromagnetic actuators to control the horizontal motion of levitated steel plates. In this study, we examined the change in the levitation stability during noncontact transport with the addition of positioning control in the horizontal direction or changed transport conditions. As a result, the application of a magnetic field in the horizontal direction improved the levitation stability of transported thin steel plates in different transport conditions. [ABSTRACT FROM AUTHOR]

In this study, we conducted a quantitative evaluation of the comfort of the interior of an electric vehicle (EV) using the brain wave appearance rate, which is part of the human biologic information that the initial stage of the proposed active noise control (ANC) system for ultra-compact EVs reveals. EVs have become easy-to-use mobility solutions and have been researched and actively developed focusing on using music characteristics. We performed fundamental testing of music including 1/f fluctuation for the evaluation of ride comfort based on the relationship between the participant's heart rate and tempo of music using a driving simulator. The results suggest that if a passenger listened to music including a 1/f fluctuation, then he/she could relax. Thus, it was concluded that if we could pre-grasp the passenger's biologic information of the heart rate and beats per minute for masking, then the comfort in the interior space could be improved even when using a driving simulator. [ABSTRACT FROM AUTHOR]

In a plating process, a steel plate is conveyed for 20–50 m in the vertical direction for drying, during which it is weakly supported by rollers or other devices, resulting in uneven plating due to vibration and other productivity-reducing factors. We developed a non-contact guide system for a high-speed traveling elastic steel plate in which electromagnetic forces are applied by actuators on the edges of the plate to control its position. Furthermore, we conducted a travelling experiment in which permanent magnets were installed in the linear part of the steel plate to suppress the vibrational effects. We report the results of our experiment and simulations to show the effectiveness of our proposed method. By placing the permanent magnets at the antinodes of vibration in the linear portion, vibration in the loop-shaped part were suppressed. From these results, it is clarified that the guide performance of the loop shaped part can be improved by reducing the vibration of the straight portion. [ABSTRACT FROM AUTHOR]

Ultra-compact electric vehicles are becoming popular means of personal mobility. However, due to their small size, it is difficult to install an assist mechanism for steering operation in most of these vehicles. As a solution, the research team proposes the application of the steer-by-wire system (SBWS) to control the front tires of the vehicle without any mechanical connection. By changing the steering gear ratio and steering wheel reaction torque, SBWS can provide optimal operability and driving comfort. In this study, an experimental vehicle is equipped with SBWS and the steering reaction torque of the steering wheel based on the steering angle as feedback is adjusted. The experimental results show that changing the steering wheel reaction torque affects driver muscle burden. [ABSTRACT FROM AUTHOR]

When an ultrathin and flexible steel plate is to be levitated, levitation control becomes difficult because the ultrathin steel plate undergoes increased flexure. We have proposed the levitation of an ultrathin steel plate that is bent to an extent that does not induce plastic deformation. In this study to elucidate the levitation stability under disturbance, a random disturbance was input into the levitation system and bending levitation experiments were carried out using an ultrathin steel plate with a thickness of 0.19 mm. [ABSTRACT FROM AUTHOR]

In the transport system of a thin steel plate production line, the quality of the plate surface deteriorates over time because of contact with rollers. As a solution to this problem, the noncontact transportation of steel plates using an electromagnetic force has been proposed. To improve the levitation performance of the conventional magnetic levitation system, we have proposed the use of an electromagnet to control the horizontal displacement of the steel plate. By using a horizontal electromagnet a vertical force to support the steel plate and a horizontal force to suppress elastic vibration act on the steel plate. Focusing on these forces, we have proposed a magnetic levitation system for a steel plate with simultaneous horizontal positioning control and vertical non-contact support using a horizontal electromagnet. In this study, we measured the vertical suspension force including levitation from experimental results. We investigated the levitation performance of a steel sheet by performing a levitating experiment using a newly manufactured magnetic levitation system. [ABSTRACT FROM AUTHOR]

Bioinstrumentation has been used in the automotive industry to evaluate the ride comfort level of different vehicles. However, there have been no studies attempting to incorporate bioinstrumentation in the controls. In this paper, we propose a ride comfort control system using the psychological state of the driver as estimated through bioinstrumentation. To evaluate the psychological state of the driver, we use the driver's heart rate variability, which allows us to calculate the R-R interval and the LF/HF, the values of which reflect the activities of the autonomic nervous system. In this paper, we investigated the usefulness of a ride comfort control system using adequate bioinstrumentation and switching criterions for the system. As the results indicate, the drivers become relaxed when using the ride comfort control system as based on their psychological state. Moreover, the drivers become more relaxed when using LF/HF as the switching criterion for ride comfort. [ABSTRACT FROM AUTHOR]

Thin steel plates are widely used in various industrial products. However, deterioration of their surface quality and metal plating occur to movement. As a solution to these problems, non-contact transportation of a steel plate using electromagnetic force has been proposed. In this study, a thin steel plate (0.24 mm thickness) was magnetically levitated, and we carried out experiments using the one-degree of freedom model and continuous model for levitation control to determine the effect of a magnetic field from the horizontal direction applied to the levitated steel plate on its elastic vibration. [ABSTRACT FROM AUTHOR]

With recent advances in technologies such as those of semiconductors and actuators, easy-to-control compact actuators have been actively applied in various fields such as factory automation and precision machining. In the automobile industry, major manufacturers and venture companies are also concentrating on electric vehicle development. Ultra-compact mobility vehicles, which exhibit an excellent environmental performance and are highly convenient for short-distance movement, are becoming popular. However, owing to cabin space limitations, it is difficult to mount systems such as power steering for assisting steering operations, and such systems are currently not installed in most ultra-compact mobility vehicles. Our research group focused on a steer-by-wire system that does not require a physical connection between the steering wheel and the wheels. Using this system, the steering wheel can be installed without any constraints, and the cabin layout can be easily changed. The reaction torque applied to the steering wheel can be expected to provide an optimum steering feel to each driver by controlling the reaction-force-generating actuator output. Drivers with different heights and arm lengths were then grouped, and arm model calculation and electromyogram measurements obtained during steering operations were used to examine the muscle burden experienced during driving owing to differences in the drivers' physiques. [ABSTRACT FROM AUTHOR]

When an ultrathin and flexible steel plate is to be levitated, levitation control becomes difficult because the ultrathin steel plate undergoes increased flexure. We herein propose a levitation method for an ultrathin steel plate that is bent to an extent that does not induce plastic deformation. In this study, to investigate the levitation stability of an ultrathin steel plate, we applied disturbance cancellation control in the bending levitation system. The object of electromagnetic levitation was a rectangular zinc-coated ultrathin steel plate (SS400) of length 800 mm, 600 mm, and thickness 0.19 mm. The vibrator was attached below the three frames, in which the electromagnet unit was installed so that the frames could be vibrated up and down. We conducted experiments on the levitation performance when the electromagnet was displaced by the frame vibration in the bending levitation system. The results showed that a stable levitation can be achieved even with an input of external disturbance when levitating at the optimum bending angle. [ABSTRACT FROM AUTHOR]

The ultra-compact electric vehicle has recently experienced increasing popularity for short-distance travel. However, one of the issues with ultra-compact electric vehicles is that although the engine is silent, exterior road and wind noise have a significant impact on the occupant's comfort in the interior space. We propose an ANC system whereby a kind of small actuator is installed on the roof of an ultra-compact electric vehicle. In this paper, we consider the noise control effects of using a giant magnetostrictive actuator and conduct an experimental study on feed-forward and feedback control systems. [ABSTRACT FROM AUTHOR]

In a plating process, the steel plate is conveyed 20–50 m in the vertical direction for drying, during which it is negligibly supported by rollers and other mechanisms. This produces plating without uniformity owing to the generation of vibration and other factors, which prevent the increase in productivity. We have developed a noncontact guide system for a high-speed traveling elastic steel plate in which electromagnetic forces are applied by actuators at the edges of the plate to control the plate's position. In this study, we investigated the vibration phenomenon when changing the steady current value of the electromagnet used for controlling the position. In addition, we conducted mode analysis of the steel plate to enable stable control even at low steady current values and verified whether stable guide can be provided by using it together with a permanent magnet. As a result, by arranging the permanent magnets, stable guidance was possible even at a low steady current value. In addition, it became clear that vibration damping performance is also improved. [ABSTRACT FROM AUTHOR]

Active seat suspension has been proposed to improve ride comfort for ultra-compact mobility. Regarding the ride comfort of passengers due to vertical vibration, the authors have confirmed from biometry measurements that reduction of the vibration acceleration does not always produce the best ride comfort for passengers. Therefore, heart rate variability that can quantitatively reflect stress is measured in real time, and a control method was proposed that feeds back to active suspension and confirms its effectiveness by fundamental verification. In this paper, we will confirm the influence of the vibration stress on the psychological state of the occupant by the masking method. [ABSTRACT FROM AUTHOR]