Chassis integrated control for 4WIS distributed drive EVs with model predictive control based on the UKF observer

• Published in: Science China. Technological sciences Vol. 63; no. 3; pp. 397 - 409
• Main Authors: Song, YiTong, Shu, HongYu, Chen, XianBao
• Format: Journal Article
• Language: English
• Published: Beijing Science China Press 01.03.2020; Springer Nature B.V
• Subjects: Bicycles; Chassis; Computer simulation; Control stability; Control systems; Controllers; Engineering; Impact strength; Kalman filters; Lateral stability; Predictive control; Sideslip; Steering; Subsystems; Taylor series; Tire force; Velocity; Yaw; model predictive control; Taylor expansion; integrated controller; unscented Kalman filter
• ISSN: 1674-7321; 1869-1900
• DOI: 10.1007/s11431-019-9552-6

Four-wheel independent steering (4WIS) system and direct yaw moment control (DYC) have an important influence on vehicle lateral stability. However, DYC has a great effect on the longitudinal velocity, and the capability of 4WIS is limited to stability. To decrease the influence on the longitudinal velocity and improve the stability of electrical vehicles, a chassis controller integrated with a 4WIS system and a DYC system with model predictive control (MPC) is designed. The framework consists of an unscented Kalman filter (UKF) observer and an MPC that contains three blocks: supervisor blocks, upper blocks and lower blocks. First, the sideslip angle, longitudinal velocity and lateral tire forces are estimated by the UKF observer; second, a bicycle model is utilized in the supervisor to calculate the desired values; third, the upper blocks are designed with the MPC to optimize the target steering angles and longitudinal tire forces under the constraints of subsystems; to facilitate the design of the MPC, a nonlinear tire is simplified based on the Taylor expansion method; finally, the target steering angles and longitudinal tire forces are achieved by the lower blocks. The integrated controller is simulated on the co-simulation platform of MATLAB-Carsim. The results show that the proposed integrated controller has less impact on longitudinal velocity and could effectively improve vehicle stability.