Long Short-Term Memory–Model Predictive Control Speed Prediction-Based Double Deep Q-Network Energy Management for Hybrid Electric Vehicle to Enhanced Fuel Economy
Haichao Liu, Hongliang Wang, Miao Yu, Yaolin Wang, Yang Luo
Abstract
How to further improve the fuel economy and emission performance of hybrid vehicles through scientific and reasonable energy management strategies has become an urgent issue to be addressed at present. This paper proposes an energy management model based on speed prediction using Long Short-Term Memory (LSTM) neural networks. The initial learning rate and dropout probability of the LSTM speed prediction model are optimized using a Double Deep Q-Network (DDQN) algorithm. Furthermore, the LSTM speed prediction function is implemented within a Model Predictive Control (MPC) framework. A fuzzy logic-based driving mode recognition system classifies driving cycles and identifies real-time conditions. The fuzzy logic-based driving mode is used to divide the typical driving cycle into different driving modes, and the real-time driving modes are identified. The LSTM-MPC method achieves low RMSE across different prediction horizons. Using predicted power demand, battery SOC, and real-time power demand as inputs, the model implements MPC for real-time control. In our experiments, four prediction horizons (5 s, 10 s, 15 s, and 20 s) were set. The energy management strategy demonstrated optimal performance and the lowest fuel consumption at a 5 s horizon, with fuel usage at only 6.3220 L, saving 2.034 L compared to the rule-based strategy. Validation under the UDDS driving cycle revealed that the LSTM-MPC-DDQN strategy reduced fuel consumption by 0.2729 L compared to the rule-based approach and showed only a 0.0749 L difference from the DP strategy.