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There are strong demands for vehicle weight reductions so as to improve fuel economy. At the same time, it is also necessary to ensure crash safety. One effective measure for accomplishing such both requirements conflicting each other is to apply advanced high strength steel (AHSS) of 780 MPa grade or higher to the vehicle body. On the other hand, higher strength steels generally tend to display lower elongation causing formability deterioration. Nissan Motor Corporation have jointly developed with steel manufacturers a new 980 MPa grade AHSS with high formability with the aim of substituting it for the currently used 590 MPa grade high-tensile steel. Several application technologies have been developed through the verifications such as formability, resistance spot weldability, crashworthiness, and delayed fracture.

For active front steering control systems that intervene in driver's operation to assist in the control of the vehicle's motion, the effect of the man-machine interface is much larger than for other conventional control systems. This paper focuses on human factors. The results of analysis regarding control effects and system design concerns are also described. The user benefits of this control system are improved vehicle stability and reduced driving workload. Both theoretical and experimental evaluations are described. Regarding the man-machine interface, the influence of the oversteer characteristic when braking and turning on driver's steering operation, the influence of driver reaction in system failure and steering wheel reaction torque when driving with the actuator are also analyzed.

Chassis control systems, including ABS, traction control and vehicle stability control, utilize the available tire forces to improve vehicle acceleration, deceleration, handling and stability for active safety. Thus, it can be very beneficial to evaluate the tire force characteristics on actual road surfaces and use this information in the chassis control systems. In this paper, the research activities on evaluating the tire force characteristics and the performance of chassis control systems are introduced. The test procedure described for measuring the tire force characteristics on actual road surfaces using a test vehicle is relatively easy. The brake and side force characteristics are shown from the experimental data. The tire force characteristics during ABS braking were measured on various road surfaces. ABS performance is discussed based on the measured tire force characteristics.