Kazuhiko Shimada

Improvement of Vehicle Maneuverability by Direct Yaw Moment Control

SUMMARY This paper deals with a study to theoretically formulate an effective method of improving vehicle performance, particularly, its characteristics in the nonlinear region, and to verify the feasibility of the proposed method by calculations and examinations. In order to analyze vehicle characteristics in the nonlinear region, a new method of analysis was developed for determining yaw moment and side force of the vehicle with a parameter of the side slip angle at the center of gravity when its center of gravity point was fixed. The study with this new method found that direct yaw moment control by proper distribution of traction and braking forces on the right and left tires could provide a very effective means of stabilizing vehicle characteristics, specifically for acceleration and deceleration, and enlarging the limit of vehicle maneuverability.

Improvement on limit performance of vehicle motion by chassis control

Studies were made on the effects of braking force distribution, on a vehicles lateral and longitudinal directions. The studies were made on distribution on non-linear regions, under combined high lateral acceleration and deceleration conditions, using the value of the yaw moment versus the side slip angle. Consequently, a method for obtaining optimum braking force distribution was found. Controlling the lateral distribution of the braking force on the front wheels was found to be effective for the improvement of vehicle stability, while that on the rear wheels was found to be effective for extending the limit of vehicle motion. Therefore, controlling the lateral distribution of the braking force on both the front and rear wheels achieves the two effects mentioned above. Simulation tests were carried out to confirm these effects in terms of turning performance and controllability to avoiding obstacles in emergency situations. (A) For the covering abstract see IRRD 864807.