Backlash-based Shock Isolation Control for Jerk Reduction in Clutch Engagement

Abstract

Coasting is a fuel-efficient driving technique for hybrid vehicle that increases cruising distance by separating the engine using a clutch. When a driver needs to accelerate a vehicle in the coasting mode, the engine restarts and the clutch is engaged automatically. At this time, clutch engagement shock and re-acceleration time delay are uncomfortable for the driver. Generally, a hybrid vehicle is regarded as a two-inertia system with a clutch and backlash. This paper proposes backlash-based shock isolation control that isolates clutch engagement shock from a vehicle using gear backlash. The proposed method reduces shock by gently meshing gear backlash using speed difference control between the input and output sides of gear backlash. Thereafter, vibration suppression acceleration is performed through I-P-I-P type torsion torque control. The magnitude of the shock is quantitatively evaluated based on jerk, which is a derivative of acceleration. The effectiveness of the proposed control method is confirmed through numerical simulations and small simulator experimental results. In the experimental results, a 62% reduction in jerk is obtained using the proposed method.