Numerical treatment of the optimal energy control problem of hybrid vehicles

We address the energy-management problem of a hybrid electric vehicle. We present a modeling framework that allows us to establish the dynamics of a hybrid electric vehicle and formulate an optimal control problem for minimizing the total fuel consumption when the vehicle follows a preassigned driving profile. The optimal motor control is computed by discretizing the control problem and using nonlinear programming methods. The computed controls are piecewise almost constant and thus can be closely approximated by piecewise constant controls. The optimization of the piecewise constant control values considerably speeds up the optimization process and will be useful in practical applications using real-time control techniques.