Evolving Finite State Machines for the Propulsion Control of Hybrid Vehicles

Hybrid Vehicles (HVs) are proposed as a candidate to conventional vehicles. Characteristic for HVs is the use of a temporary energy buffer. But the control of the Primary Power Unit (PPU), e.g. an otto engine or a fuel cell, is much more complex than in conventional vehicles. This paper deals with a method to design a control algorithm for the PPU in a HV. Here, a Finite State Machine (FSM) is used as the control architecture and is trained using an evolutionary algorithm. A control sequence is derived from a simplified vehicle model and used to train the FSM. The evolved FSM is then used to control a much more accurate computer model of a vehicle. A special technique, which is introduced in this paper, has been developed, which considerably increases the speed of evolution. A realistic example of an implementation of a control algorithm in a virtual prototype is also presented. Key-words: Hybrid vehicle, Control strategy, Control algorithm, Propulsion control, Finite State Machine, Evolutionary algorithm.