Fuzzy sliding mode control for smooth mode changes of a parallel hybrid electric vehicle

The control objective of minimization of the fuel consumption and exhaust emission in hybrid electric vehicle (HEV) has generally been achieved by a supervisory controller. The drivability and NVH of HEV especially during mode changes, on the other hand, have drawn significant attention in recent years. In this paper, for the purpose of control simulation, a hybrid drivetrain model including a slipping clutch is first developed. A robust control strategy based on fuzzy sliding mode control (FSMC) technique is then proposed for smooth mode changes of HEV. Simulation results demonstrate that smooth and fast transition from pure electrical driving to hybrid driving can be achieved by controlling the integrated starter generator (ISG). The FSMC smoothing controller, along with a rule-based supervisory controller, is robust against modeling uncertainties in the vehicle mass and the friction coefficient of the clutch.