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In this research, we examine the three controls inside-outside wheel braking force and driving force, camber angle, and the derivative steering assistance to determine how angle differences affect cornering performance and controllability. This is accomplished by comparing body slip angle area differences in a closed loop examination of the grip to drift area using a driving simulator. The results show that inside-outside wheel braking force and driving force control in the area just before critical cornering occurs has a significant effect on vehicle stability. We also clarified that controlling the camber angle enhances grip-cornering force, and confirmed that the sideslip limit could be improved in the vicinity of the critical cornering area. Additionally, when the counter steer response was improved by the use of derivative steering assistance control in the drift area exceeding the critical cornering limit, corrective steering became easier.

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.

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.