Intelligent Hierarchical Coordinated Control for Off-Road Series Hybrid Electric Vehicles Energy Management and Electric Power Response

Abstract

The series hybrid electric vehicle (SHEV) features mechanical decoupling between the front and rear powertrains. Consequently, the vehicle's dynamic performance is significantly influenced by the dynamic response behavior of its electrical power system. In this paper, a real-time online optimization hierarchical control framework is proposed according to changeable off-road driving conditions, which considers fuel economy, SOC preservation, and vehicle dynamics. The innovation of this paper is that two new valuable algorithms are proposed in the upper and lower level of control strategy, respectively. In the upper-level controller, energy management strategy based on expected SARSA is established to optimize fuel economy and battery SOC maintenance. In the lower-level controller, rapid electric power response and energy management of SHEV are balanced in coordination control strategy by establishing the optimization function as a piecewise function, and adaptive network-based fuzzy inference system (ANFIS) is updated by Q-learning to obtain optimization solution and control on-line. Under the conditions of high-speed flat road and low-speed undulating road, the real-time capability and validity of our hierarchical control scheme are demonstrated by both simulation and hardware-in-the-loop test outcomes.