Investigation on improvement of vehicle ride comfort based on integrated chassis control

A new function of the integration control of active suspension and active braking is introduced in this paper. A novel multi-level integrated chassis control (MICC) algorithm is developed for this function to improve ride comfort during braking. The structure of the MICC includes upper and lower levels. Considering driving safety, the MICC is road-based and adaptive. Therefore, the estimation of the vehicle speed and road adhesion coefficient is proposed at the upper level to guide the integrated chassis control. Furthermore, active suspension and active braking systems, controlled by a coordination controller, are integrated to cooperatively improve the vehicle ride comfort without losing safety at the lower level. A time-domain analysis-based algorithm integrated with the genetic algorithm is developed for the active braking system to suppress the pitch, which creates a global time-domain comfort control against traditional comfort control at the end of the braking. A fuzzy PID is utilized for the active suspension system to provide additional pitch moment. Finally, real vehicle experiments are carried out for the verification of the newly designed function. Results demonstrate that the MICC can achieve superior vehicle stability performance, guarantee the given safety constraints, and significantly improve ride comfort during braking. This study contributes to improving the vehicle ride comfort, and the new function has already been implemented in several production vehicles.