In this paper, a lateral controller is designed for four-wheel steering (4WS) vehicles. The linear lateral dynamics of 4WS vehicles are deduced and then analysed, aided with three-dimensional graphs. To improve vehicle handling and stability at high speed, a multiobjective H ∞ optimal control algorithm is presented, while yaw rate is the only feedback signal. Simulation shows that the sideslip angle, yaw rate, and lateral acceleration of the 4WS vehicle follow and maintain preferable characteristics. The 4WS vehicle is agile and consistent with the steering input and does not understeer excessively.

To improve the vehicle handling stability, a four-wheel steering (4WS) controller with yaw rate tracking is proposed in this paper. A driver/ vehicle closed-loop system is built based on the preview-follower theory to evaluate the system's manoeuvring performance. Next, the system driving on a double lane-change road and on a low adhesion road are simulated and compared with conventional front-wheel steering vehicle. The Fourier transform method is developed to analyse the dynamics of the closed-loop system in the frequency domain. The results show that the proposed 4WS vehicle has the preferred response characteristics of sideslip angle and yaw rate, and is robust regarding tire cornering stiffness, which guarantees the handling stability in emergency braking condition.

Aiming at the cruising range of electric vehicles, this paper proposes a control strategy for electric vehicle electromechanical composite braking mode switching based on motor braking force correction. The braking force of the motor is adjusted by factors such as braking intensity to improve the braking energy recovery, and the braking force distribution curve is designed considering the braking energy and braking safety and stability. The research results show the braking time, braking torque, and battery charge. The peak value of discharge current has been improved, and the braking energy recovery efficiency has increased by 9.17% and 3.32% respectively under different working conditions. Under different braking modes with an initial speed of 30 km h−1, the braking energy recovered by the battery has increased by 16.04 , 3.89, 9.63 kJ, the braking time and braking distance are also shorter, which highlights the superiority of this control strategy.

This paper designs a intelligent car horn based on RFID(radio frequency identification and satellite navigation technology)。Horn gets automobile accurate geographic position information by satellite navigation chip and realize the communication between the cars by the RF module.When the other car's whistle is blowing ,the horn can accept the signal covering the vehicle speed and location information.What's more,it can quickly and accurately calculate the distance between vehicles to provide timely warning distance by sunplus. After testing,the horn is stable、reliable and adaptable, which can effectively prevent the closed windows that the driver did not hear the whistle sound caused by traffic accidents and improve traffic safety.