Sum-Of-Squares Based Vehicle Dynamic Stability Method and Its Applications in ADAS

Vehicle stability control is the core technology required for improving driving safety of advanced driver assistance systems (ADAS). In this paper, vehicle dynamic stability characteristics are investigated, and an improved vehicle stability controller is proposed to enhance the vehicle’s performance. The sum-of-squares programming is introduced to estimate its stability region and qualitative analysis is utilized to investigate the effect of various driving conditions on the stability region. An approximate dynamic stability boundary is established for different steering angle inputs. A new Lyapunov-function-based vehicle dynamic stability (LFVDS) controller is then designed to improve vehicle stability and dynamics performance based on the hierarchical structure. A test on a Hardware-In-the-Loop platform is formulated to validate the vehicle state response under the traditional and the proposed stability controllers. The results indicate that, compared with the traditional stability controller, the LFVDS controller can effectively reduce longitudinal velocity drop by 33% on a slippery road surface with ensured vehicle stability.