Search Results

A driving simulator capable of duplicating the critical sensations incurred during a spin, or when a driver is engaged in drift cornering, was constructed by Mitsubishi Heavy Industries, Ltd., and Hiromichi Nozaki of Kogakuin University. Specifically, the simulator allows independent movement along three degrees of freedom and is capable of exhibiting extreme yaw and lateral acceleration behaviors. Utilizing this simulator, the control characteristics of drift cornering have become better understood. For example, after a J-turn behavior experiment involving yaw angle velocity at the moment when the drivers attention transitions to resuming straight ahead driving, it is now understood that there are major changes in driver behavior in circumstances when simulator motions are turned off, when only lateral acceleration motion is applied, when only yaw motion is applied, and when combined motions (yaw + lateral acceleration) are applied.

In the cornering performance of a formula car, turning is performed at a considerably high level. However, few studies have investigated the control of the camber angle. Therefore, a mechanism that swings to the negative camber side of the suspension in cornering was examined in the present study. A swinging suspension member structure was assumed when a lateral force acted on the tires, and the momentary rotation center of the swing suspension member was controlled so that the direction of the swing would be to the negative camber side. As a result, compliance of the negative camber was achieved. The layout of a preferable mechanism was first determined by geometrical analysis. The negative camber angle obtained with this mechanism changes according to the length of the link for the fixation of the swing suspension member, the installation position, and the angle. The specifications for achieving a proper compliance negative camber were then clarified.

Proportional Derivative (PD) steering assistance offers potential measures by which the control stability of a vehicle can be rapidly improved. However, for all Proportional Derivative (PD) steering methods, the inconvenience caused by the need to keep turning the steering wheel during cornering is significant. Because the steering return phenomenon of the steering wheel stop like this is not so preferable, it is preferable that the Proportional Derivative (PD) steering assistance is extremely weak (almost 0) in such a usual grip cornering driving. Alternatively, in the drift area of cornering where the grip area of the tires has been exceeded, Proportional Derivative (PD) steering assistance is helpful because the driver can control his counter steering extremely well. Furthermore, only a small amount of Proportional Derivative (PD) steering assistance is required in the drift area.

I studied the driver steer characteristics in the severe lane change with a drift. And, I studied the technique by which the performance of running in the vehicle at the severe lane change with a drift was improved. It has been understood that the severe lane change with a drift is a steer proportional to the body slip angle unlike the grip running. Moreover, I have understood importance in the vehicle movement performance improvement the cornering force characteristic where the maximum cornering force of the tire was exceeded. Next, I have understood the differentiation steer assistance is more effective.

As for this research, the driver’s risk at the time of cornering was evaluated. As a result, the amount of perspiration became a big difference though the change in the amount of the vehicle state of non-drive skill person and the drive skill person did not have a remarkable difference at the time of the drift cornering. That is, the amount of perspiration when the steer is controlled in case of the drive skill person is small. Therefore, it has been understood that it is a steer control of the risk which is not too large.

In this research, driver risk (subjective feeling of danger) during pylon slalom and drift turning was evaluated by measuring the amount of driver perspiration. The result (the product of the amount of maximum perspiration and the perspiration amount area at the unit running time) is believed to correspond to a subjective rating of the feeling of danger. Moreover, a peculiar phenomenon was observed during drift cornering in which a large degree of fear was experienced if there was a possibility that the vehicle might spin, thus considerably increasing the amount of perspiration. Here, perspiration amount area shows the total amount of perspiration, additional to baseline levels, over a given time frame. And, unit running time shows the same as saying ‘averaged over time’

In this study, a steering model and vehicle velocity control model were applied for a driver in drift cornering in order to maintain an intentional drift angle at the time of cornering. The driver was assumed to steer based on feedback from the body slip angle and the body slip velocity during drift cornering. It is found that the driver not only controls the drift angle at the time of the drift cornering but also controls the turn radius by changing vehicle velocity. Moreover, at the return from drift cornering to the straightaway, feedback is based on not only the body slip angle but also the body slip angle velocity, which is differentiated steer based on the phase is advanced.

In this study, an effective technique for improving drift running performance was examined. Basically, a driver model with counter steering was examined with the assumption that the body slip angle, along with the body slip angle velocity, served as feedback. Next, the effectiveness of adding front wheel steer angle velocity feedback to steering angle compensation as a drift running performance improvement technique of a vehicle was analyzed.

A drift-turn experiment to assess the influence of differences in steering wheel gear ratios was undertaken using a driving simulator. It is relatively easy to maintain control of a commercial vehicle if the tire is in contact with the road surface and the steering wheel gear ratio is 15.0:1 to 18.0:1. Conversely, in the event of a change in traction such as the rear wheel meeting a drift area, a steering wheel gear ratio of 7.5:1 to 9.0:1 is required to maintain control of the vehicle, even when the vehicle became unstable. Moreover, the stability of the vehicle deteriorates in drift running if the steering gear ratio is reduced too much. That is, the steering gear ratio in which the drift angle is maintained most easily is in the range 7.5∼9.0. And, a drift performance evaluation index D n=x was determined and was found to agree with the subjective ratings. Thus, evaluating drift control for drift cornering using the drift performance evaluation index was assumed to be effective.

In this study, we focus on “camber angle control” and “derivative steering assistance” using “steer-by-wire” as maneuverability and stability improvement techniques that are appropriate for the electric vehicle (EV) era. Movements that produce a negative camber angle generate camber thrust, and vehicle motion performance improvements extend from the fact that the tire side force is increased by the camber thrust effect. In our experimental vehicle, a proportional steering angle system was used to create negative camber angle control via an electromagnetic actuator that allowed us to confirm improvements to both the effectiveness and stability of steering control in restricted cornering areas. More specifically, we determined that it is possible to improve critical cornering performance by executing ground negative camber angle control in proportion to the steering angle.