Automotive backlash position estimator for driveline jerk control

Backlash position information is important in designing control systems for the purpose of reducing clunk and shuffle in automotive drivelines. Typically, this position information is used by the control system to determine when the driveline has entered or exited the backlash and also to regulate the speed of backlash traversal. To this end, we develop here a Kalman filter-based estimator for the backlash position, utilizing readily available speed measurements from the vehicle CAN bus. The estimator is designed to switch between two modes, since the drivetrain physics is different while traversing the lash and outside of the lash. We validate the estimator using experimentally collected vehicle test data, and observe that the backlash position estimates are accurate to within 20 ms of the test vehicle's actual backlash position. Furthermore, we verify the robustness of the system to CAN jitter in the speed measurements.