SYMay 27Code
Energy-Optimal Thermal Management of Heat-Pump Battery Electric VehiclesPrashant Lokur, Nikolce Murgovski
This paper presents an energy-optimal hybrid control framework for thermal management of heat-pump battery electric vehicles (BEVs). The controller coordinates the compressor, coolant pumps, and cabin blower across the coupled refrigerant, coolant, and air loops, while enforcing cabin comfort and component temperature constraints. The framework combines a rule-based supervisory layer, which handles discrete system configuration, with a continuous nonlinear model predictive control (NMPC) optimizer that minimizes thermal energy consumption over a finite prediction horizon. A control-oriented model is developed to capture the dominant dynamics of the cabin, refrigerant loop, reconfigurable coolant circuits, and key thermal masses including the battery, motor, and inverter. The model is validated against a high-fidelity reference, achieving a mean absolute temperature prediction error below \SI{1.8}{\celsius} for key thermal states including the battery, motor, and cabin air temperature, while reducing simulation time by approximately \SI{85}{\percent}. The terminal cost is computed by linearizing the system about a quasi-steady operating point and solving the discrete-time algebraic Riccati equation, ensuring well-conditioned optimization across varying operating conditions. The proposed framework is evaluated against the built-in rule-based controller of MathWorks Simscape \emph{Electric Vehicle Thermal Management with Heat Pump} model under cold-climate extended driving conditions, demonstrating consistent reductions of \SI{20}{}-\SI{28}{\percent} in thermal energy consumption across all tested scenarios. The complete implementation, developed using the open-source CasADi framework, is made openly available at \href{https://github.com/PrashantLokur/ThermalEnergyManagementWithHybridControlFramework}{GitHub} repository to support reproducibility and further development.
LGMar 27, 2023
Prediction of Time and Distance of Trips Using Explainable Attention-based LSTMsEbrahim Balouji, Jonas Sjöblom, Nikolce Murgovski et al.
In this paper, we propose machine learning solutions to predict the time of future trips and the possible distance the vehicle will travel. For this prediction task, we develop and investigate four methods. In the first method, we use long short-term memory (LSTM)-based structures specifically designed to handle multi-dimensional historical data of trip time and distances simultaneously. Using it, we predict the future trip time and forecast the distance a vehicle will travel by concatenating the outputs of LSTM networks through fully connected layers. The second method uses attention-based LSTM networks (At-LSTM) to perform the same tasks. The third method utilizes two LSTM networks in parallel, one for forecasting the time of the trip and the other for predicting the distance. The output of each LSTM is then concatenated through fully connected layers. Finally, the last model is based on two parallel At-LSTMs, where similarly, each At-LSTM predicts time and distance separately through fully connected layers. Among the proposed methods, the most advanced one, i.e., parallel At-LSTM, predicts the next trip's distance and time with 3.99% error margin where it is 23.89% better than LSTM, the first method. We also propose TimeSHAP as an explainability method for understanding how the networks perform learning and model the sequence of information.
SYMay 8
Interactive Trajectory Planning with Learning-based Distributionally Robust Model Predictive Control and Markov SystemsErik Börve, Nikolce Murgovski, Morteza Haghir Chehreghani et al.
We investigate interactive trajectory planning subject to uncertainty in the decisions of surrounding agents. To control the ego-agent, we aim to first learn the decision distribution and solve a Stochastic Model Predictive Control (SMPC) problem. To account for errors in the learned distribution, we show that it is possible to utilize Probably Approximately Correct (PAC) learning in combination with Distributionally Robust (DR) optimization to obtain a solution which accounts for the errors induced by the learning model. The results indicate that our PAC learning-based DR-MPC framework provides a method to interpolate between a robust MPC and an omnipotent SMPC, based on the available number of samples.
LGJan 12, 2021
A Unified Framework for Online Trip Destination PredictionVictor Eberstein, Jonas Sjöblom, Nikolce Murgovski et al.
Trip destination prediction is an area of increasing importance in many applications such as trip planning, autonomous driving and electric vehicles. Even though this problem could be naturally addressed in an online learning paradigm where data is arriving in a sequential fashion, the majority of research has rather considered the offline setting. In this paper, we present a unified framework for trip destination prediction in an online setting, which is suitable for both online training and online prediction. For this purpose, we develop two clustering algorithms and integrate them within two online prediction models for this problem. We investigate the different configurations of clustering algorithms and prediction models on a real-world dataset. We demonstrate that both the clustering and the entire framework yield consistent results compared to the offline setting. Finally, we propose a novel regret metric for evaluating the entire online framework in comparison to its offline counterpart. This metric makes it possible to relate the source of erroneous predictions to either the clustering or the prediction model. Using this metric, we show that the proposed methods converge to a probability distribution resembling the true underlying distribution with a lower regret than all of the baselines.