Yuji Muragishi

Vehicle dynamics integrated control for four-wheel-distributed steering and four-wheel-distributed traction/braking systems

In this article, vehicle dynamics integrated control algorithm using an on-line non-linear optimization method is proposed for 4-wheel-distributed steering and 4-wheel-distributed traction/braking systems. The proposed distribution algorithm minimizes work load of each tire, which is controlled to become the same value. The global optimality of the convergent solution of the recursive algorithm can be proved by extension to convex problems. This implies that theoretical limited performance of vehicle dynamics integrated control is clarified. Furthermore, the effect of this vehicle dynamics control for the 4-wheel-distributed steering and 4-wheel-distributed traction/braking systems is demonstrated by simulation to compare with the combination of the various actuators.

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.

Development of a Human Sensitivity Evaluation System for Vehicle Dynamics

Although wide-ranging research to improve vehicle driving stability has been carried out [1, 2], there is still insufficient knowledge about what information from the multiple types of movement that occur during driving is used by vehicle occupants when evaluating driving stability. Moreover, various devices for vehicle dynamics control have recently been developed, thus making it possible to freely control the character of vehicle dynamics. Toyota has developed an analytical system composed of motion and visual devices for evaluating human visual and motion sensitivity to vehicle dynamics.