Vehicle dynamics and control for improving handling and active safety: From four-wheel steering to direct yaw moment control

Abstract

Recent trends of vehicle chassis control are reviewed, paying attention to the basic nature of the vehicle dynamics, tyre characteristics and the effectiveness and limit of four-wheel steering (4WS) and direct yaw moment control (DYC). It is pointed out that, taking the non-linear characteristics of tyre and vehicle dynamics into consideration, change in chassis control from 4WS to DYC inevitably improves handling performance and active safety in vehicle motion with larger slip angles and/or higher lateral accelerations. Emphasis is placed on the need to propose a control strategy based on thorough observation and understanding of the tyre and vehicle dynamics. A side slip model following DYC by sliding control is introduced and the effects of the control are discussed.