Disturbance observer design based on linearized vehicle model for unequal tractive/braking force identification

The study focuses on the methodology to take the effect of the unequal longitudinal tire forces into consideration to reinforce the accuracy of the linearized vehicle model, also known as the bicycle model. Using the estimated front and rear cornering stiffness values obtained through an adaptive scheme, the conventional bicycle model is analyzed. By forming the inverse bicycle model, a disturbance observer to estimate the unconsidered amount of yaw acceleration caused by the discrepancy between the left and right longitudinal tire forces is designed. The accuracy of the modified bicycle model is verified using CarSim, a well-known vehicle dynamics testing software, via comparing the estimated states of the conventional and modified vehicle model.