Lateral stability region conservativeness estimation and torque distribution for FWIA electric vehicle steering

Estimation of the lateral stability region and torque distribution on steering is very important to improve stability in lateral handling for all wheel drive electric vehicles. Based on the built-nonlinear vehicle dynamic model, the lateral stability region of the vehicle related to steering is estimated using Lyapunov function. We obtained stable equilibrium points of non-straight driving according to the estimated lateral stability region and also reconstructed the Lyapunov function matrix, which proved that the closed-loop system composed of yaw rate and lateral velocity is satisfied with negative definite property. In addition, the designed controller dynamically allocates the drive torque in terms of the vertical load and slip rate of the four wheels. The simulation results show that the estimated lateral stability region and the designed controller are satisfactory in handling stability performance against different roads and vehicle parameters.