Yoshiyuki Yasui

Estimation of automotive tire force characteristics using wheel velocity

Abstract It is important to estimate friction force characteristics between tire and road in order to improve the control performance of a vehicle in critical motions. In this paper, an estimation method which estimates parameters concerned with a friction force margin is proposed by applying the on-line least-squares method to wheel rotational velocities. The effect of the estimation is evaluated by applying the method to the braking control.

Estimation of Lateral Grip Margin Based on Self-aligning Torque for Vehicle Dynamics Enhancement

It is well known that the self-aligning torque decreases before lateral force is saturated. Focusing on this self-aligning torque change, an estimation method has been developed to detect the friction condition between steered wheels and road surface before the lateral force reaches the friction limit. The lateral grip margin (LGM) is defined based on the self-aligning torque change, which is obtained using the EPS torque and motor current information. The LGM is theoretically analyzed based on the tire model and experimentally verified through the full-scale vehicle test. Moreover, the estimated LGM is applied for the chassis control systems to improve the vehicle dynamics performance.

VEHICLE LATERAL CONTROL DEVELOPMENT USING LASER RADAR TO DETECT REFLECTIVE LANE MARKERS

SUMMARY Traffic accidents and congestion are problems which are becoming increasingly severe for automotive traffic and transportation systems. The prevention of severe accidents caused by a drivers inadvertent departure from the traffic lane presents a challenging problem due to the ever growing demands on the current vehicle and highway infrastructure. Inadvertent lane departure can be prevented by automatic lateral control of the vehicle, a component of an Automated Highway System (AHS), As a method of addressing this problem, we are developing a lateral control system which features the use of currently existing infrastructure elements such as reflective lane markers to provide a reference of the roadway ahead. A dynamic vehicle model including the tire characteristics and the steering actuator dynamics was developed to verify the performance of the lateral control algorithm. An important milestone was reached when the system was installed in an automobile and tested in an actual highway environment ...