Experimental evaluation of tire-road forces and sideslip angle observers

Knowledge of vehicle dynamic data is essential for improving vehicle safety, handling characteristics and comfort. This paper proposes a new estimation process to estimate longitudinal/lateral tire-road forces, sideslip angle and wheel cornering stiffness. This method uses measurements from currently-available standard sensors (yaw rate, longitudinal/lateral accelerations, steering angle and angular wheel velocities). The estimation process is separated into two blocks: the first block contains an observer whose principal role is to calculate tire-road forces without a descriptive force model, while in the second block an observer estimates sideslip angle and cornering stiffness with an adaptive tire-force model. The different observers are based on an Extended Kalman Filter (EKF). The estimation process was applied and compared to real experimental data, notably sideslip angle and wheel force measurements acquired using the INRETS MA Laboratory car. Experimental results show the accuracy and potential of the estimation process.