Real Time Implementation and Hardware Testing of a Hybrid Vehicle Energy Management Controller Based on Stochastic Dynamic Programming

Abstract

An energy management controller based on shortest path stochastic dynamic programming (SPSDP) is implemented and tested in a prototype vehicle. The controller simultaneously optimizes fuel economy and powertrain activity, namely gear shifts and engine on–off events. Previous work reported on the controller's design and its extensive simulationbased evaluation. This paper focuses on implementation of the controller algorithm in hardware. Practical issues concerning realtime computability, driver perception, and command timing are highlighted and addressed. The SPSDP controllers are shown to run in realtime, gracefully handle variations in engine start and gearshiftcompletion times, and operate in a manner that is transparent to the driver. A hardware problem with the test vehicle restricted its maximum engine torque, which prevented a reliable fuel economy assessment of the SPSDP controller. The data that were collected indicated that SPSDP controllers could be straightforwardly designed to operate at different points of the fuel economy tradeoff curve and that their fuel economy may equal or exceed that of a baseline industrial controller designed for the vehicle.