Dynamic Target Yaw-rate Design for Chassis Control

Abstract

Abstract

Dynamic Target Yaw-rate Design for Chassis Control

Kwanwoo Park School of Mechanical and Aerospace Engineering The Graduate School Seoul National University

This paper presents a dynamic target yaw-rate design method for chassis control system. The target yaw-rate is essential for the supervisor of the Integrated Chassis Control(ICC) algorithm. The supervisory controller monitors the vehicle status and determines desired vehicle motions such as a target yaw-rate. The target design is important because the inputs such as lateral force, yaw moment are calculated according to this target motion in the upper and lower level controller. Conventional target design is parameter optimization for a specific scenario and road condition. However, this has the disadvantage of lacking interchangeability between different scenarios. In this paper, research has been conducted to make the target yaw-rate design universal. The proposed design method consists of two parts: A bicycle model, which is considered transient handling characteristic, and Relaxation Length Tire (RLT) model which is the dynamic tire model. First, the existing bicycle cornering kinematics that assumes the steady state is reformulated as a model considering the yaw acceleration, a transient characteristic. Second, the target yaw-rate considering the RLT model serves to compensate the phase delay. The proposed method can contributes to securing the performance and lateral stability of the Integrated Chassis Control(ICC) system by increasing the responsiveness of the model to the level of the actual vehicle. After investigating the suitability of the vehicle motion simulation, it is also investigated the influence of the control input required by using the direct yaw moment control when applying it as the supervisor of the chassis control algorithm. The proposed method has been investigated under several standard maneuvers via simulation with CarSim vehicle dynamics software and Matlab/Simulink and vehicle test data. The results show the proposed target yaw-rate which is incorporating transient handling characteristics well represents natural vehicle response such as phase delay and agility from mild handling maneuver to the limit handling maneuver. It has also been confirmed that it can alleviate the sense of difference that the driver felt from the existing over-control.

Keywords: Chassis control, Target yaw-rate design, Vehicle stability control, Lateral vehicle dynamics, Transient handling characteristics Student Number: 2015-22713