H∞ control for hybrid electric vehicles

The aim of this paper is to propose a robust approach to the development of supervisory control strategies for hybrid-electric drivetrains. The objective is to determine an output feedback controller that minimizes fuel consumption with respect to a family of possible torque/power input profiles, e.g. urban driving cycles. A quasi-static energy model for the hybrid vehicle, based on a Willans lines model of the IC engine and electric motor, is derived. A linear fractional representation (LFR) of the system is then obtained where the model is described by a "nominal" linear time-invariant (LTI) system connected to an uncertainty block. Finally, the controller is derived and some simulations for a parallel hybrid architecture are included.