Robust bank angle estimation for rolling stability control on electric vehicle

In this paper, vehicle state variables and bank angle estimation for rolling stability control (RSC) is proposed using one accelerometer and two gyro sensors, instead of using inertial navigation system (INS) or global positioning system (GPS). We proposed a novel robust RSC for in-wheel motor electric vehicle (IMEV) using differential torque by right and left motors which are controlled independently. On bank road, reference lateral acceleration should be corrected properly because output of accelerometer contains a gravity term by the inclination of the sprung mass. Bank angle should be estimated for the high performance RSC too. In this paper, vehicle yaw and roll motion equations are described. Influence of road bank is assumed as disturbance input to the vehicle dynamics at first. Then bank angle is redefined as a state variable and estimated by Kalman filter. Adaptive identification method with respect to cornering stiffness is applied for robust estimation and minimum-order observer is applied to reduce the amount of calculation. In this process, it is shown that vehicle roll angle can be calculated using an accelerometer and a gyro sensor. Validity of proposed methods is verified by simulation results.