Optimal Brake Distribution for Electronic Stability Control Using Weighted Least Square Allocation Method

Abstract

Electronic stability control (ESC) system is well known as a method to assist the driver in recovering from unintended situations, such as understeering and oversteering behaviors. One of issues of this ESC is precise distribution of the brake force for generation of the vehicle yaw moment. In this paper, a new design of ESC systems is proposed. First, the model based controller with vehicle bicycle model computes the correction yaw moment, which makes the vehicle follow the desired yaw rate. Then, weighted least squares (WLS) allocation method minimizing the user-defined cost function with equality constraints is implemented for generation of the brake pressures of individual wheels. In addition, taking both weight shifting caused by pitching motion of the vehicle body and minimum disturbance of longitudinal dynamics into account, the limits of brake pressures are managed in real time. The performances of the proposed algorithm are verified in the simulation environments using Carsim and Matlab/Simulink.