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It has been reported that steering systems with derivative terms have a heightened lateral acceleration and yaw rate response in the normal driving range. However, in ranges where the lateral acceleration is high, the cornering force of the front wheels decreases and hence becomes less effective. Therefore, we applied traction control for the inner and outer wheels based on the steering angle velocity to improve the steering effectiveness at high lateral accelerations. An experiment using a driving simulator showed that the vehicle's yaw rate response improved for a double lane change to avoid a hazard; this improves hazard avoidance performance. Regarding improved vehicle control in the cornering margins, traction control for the inner and outer wheels is being developed further, and much research and development has been reported. However, in the total skid margin, where few margin remains in the forward and reverse drive forces on the tires, spinout is unavoidable.

In recent years, the conversion of vehicles to electric power has been accelerating, and if a full conversion to electric power is achieved, further advancements in vehicle kinematic control technology are expected. Therefore, it is thought that kinematic performance in the critical cornering range could be further improved by significantly controlling not only the steering angle but also the camber angle of the tires through the use of electromagnetic actuators. This research focused on a method of ground negative camber angle control that is proportional to the steering angle as a technique to improve maneuverability and stability to support the new era of electric vehicles, and the effectiveness thereof was clarified. As a result, it was found that in the critical cornering range as well, camber angle control can control both the yaw moment and lateral acceleration at the turning limit.

In a new technology called “in wheel motor,” in which the motor is installed in the wheel, the electric vehicle can become more compact, which leads to a new type of mobility. Moreover, the front wheel steering is controlled by an electrical unit instead of the traditional mechanical unit of a steering wheel inside the car. In such a “steer-by-wire” method, the motor uses an electric signal. Because the degrees-of-freedom of this steer control are increased and a variety of steer controls based on the electric signal are possible, further improvement of the control stability is needed. In other words, the steer control technique can pose a problem for drivers, and so further research in this area is needed. That is, proportional derivative steering assistance can improve emergency evasion performance and the steering delay upon counter steering. Moreover, rear-wheel active steering can improve vehicle response during emergency evasion maneuvers.

The relation of the front wheel steering angle to the steering wheel angle in electric vehicles is changing due to the “steer-by-wire” method, which is based on an electric signal. With this method, excellent maneuverability is possible in various driving situations. Therefore, this steer control method technique is considered in this study. It was clarified that steer-bywire requires an improvement in the control stability in emergency maneuvers and the delay of counter steering in drift cornering without causing a sense of driver incompatibility. (Here, the sense of incompatibility was defined as feeling by which the harmony between the steer intention of the driver and the vehicle movement was lost.) (Here, the drift cornering shows cornering done in the area with counter steering where the rear wheel exceeded the maximum cornering force.) One control stability method is Proportional Derivative (PD) steering assistance, which is dependent on the anticipated driving situations.

To improve both the sensing of grip critical cornering and drift control, it is desirable to increase the body slip angle at critical cornering. To discover why this facilitates driver control, the gaze of the driver was monitored, and the relationship between the gaze movement of the driver and the vehicle behavior was investigated. It was found that the driver steered by gazing at the target course in the direction of the inside forward of the vehicle in the grip driving area. On the other hand, the gaze movement of the driver corresponded to the change in the body slip angle in the grip critical cornering area-drift cornering area. That is, in the drift driving area, it was found that the drift was controlled by gazing at the direction of the drift angle of the outside forward of the vehicle, feeding back the body slip angle, and sensing the change from the grip critical cornering to the drift area.

Various studies have been done into the steering models that describe how the driver steers the vehicle. However, no steering models for critical cornering have been developed. In this paper, the steering characteristic was investigated by monitoring the gaze of the driver during critical cornering. The direction of the steering model during critical cornering was considered. Since the driver can readily perceive the vehicle body slip angle if body sensory information is combined with visual information, it is important for the driver to be able to look at the target course easily and to control the drift well. Drivers exhibit the tendency to position their gaze point on a difficult corner exit to drive when body sensory information is combined with visual information. Thus, it was found that the driver can perceive the roll motion and visual feedback the body slip angle, and drive while stabilizing the vehicle from the corner exit to back straight.

The following has been understood for the change in the steer characteristic and the amount of perspiration in the drift cornering when not only visual information but also body sensory information is added. When body sensory information joins visual information as for the driver, it has been understood that the amount of perspiration increases overall and can do the drift control continuing with a moderate tension. In the drive only of visual information, the driver comes to arrive easily at spin because the drift control is difficult. And, it has been understood that the amount of perspiration increases greatly compared with the case to give body sensory information, and becomes the one with a very high risk. Moreover, the driver can control an adequate drift compared with driving only visual information in feed back body sensory information on the roll angle to the steer.