Active oscillation control of electric vehicles with two-speed transmission considering nonlinear backlash

The nonlinear backlash can influence the driveability of the electric driveline due to the lack of the traditional clutches and torsional damper devices. During the stand-start, regenerative braking and gear shift process of the electric drive system equipped with two-speed transmission, the request of transient traction motor change will transverse the powertrain backlash, which will excite the driveline oscillations coupled to the first rigid mode of the entire powertrain, referred as shuffle or shunt. These vibrations are transmitted to the chassis, causing deterioration in passenger comfort. In this paper, the nonlinear driveline model including the traction motor, half shaft, driveline backlash, and car wheel are developed. Then, dual extended Kalman filter method is employed to estimate vehicle mass and half shaft torsional angle of the proposed driveline. Based on the estimated information, a hierarchical architecture of the active oscillation compensation is proposed to alleviate the vibration in both contact and backlash mode. The experimental results show that the estimation method is effective and the vehicle shuffle can be significantly decreased by the developed control algorithm.