Model Based Algebraic Weight Selection for LQI Control Reducing Dog Clutch Engagement Noise

This paper presents a feedback control strategy to minimize noise during dog clutch engagement in a hybrid transmission. The hybrid transmission contains an internal combustion engine(ICE) and 2 electric motors in P1 and P3 configurations. For efficiency during driving, at high vehicle speeds ICE is connected to wheels, via the dog clutch, hence shifting the vehicle from series to parallel hybrid mode. It is shown by experimental results that if the speed difference between the two sides of the dog clutch is below a certain level the engagement will be without clonk noise. In this paper the designed state feedback Linear Quadratic Integral (LQI) control provides the synchronization torque request to the P1 motor, hence matching the speed of one side of dog clutch with the other under the disturbance from combustion torque of the engine. Normally LQI controllers are tuned by trial-and-error methods, but this paper presents an algebraic approach where the feedback gains of the LQI controller are calculated based solely upon the physical parameters of the system, the required time for speed synchronization and acceptable values of speed difference from experimental results. This approach minimizes the need for manual tuning and can deliver the controller gains for any size and version of the transmission by just modifying the parameter values and functional requirements. The results are shown by simulations on a 2DOF torsional system representing ICE, dual mass flywheel and P1 electric motor.