Real-Time Multibody Co-Simulation of Thermal and Electromechanical Systems in an Electric Wheel Loader Model

Abstract The electrification of on-road and off-road vehicles is increasing due to the depletion of fossil fuels and emissions from internal combustion engines (ICE). Real-time simulation analysis of electric vehicles can aid in both the design and analysis processes, enabling users to actively participate in the design phase. However, the computational costs associated with various subsystems, such as electro-thermal dynamics, hydraulics, tires, friction, and contacts etc. make real-time computational efficiency of electric vehicles cumbersome. To this end, this study introduces the real-time multibody co-simulation of multibody, hydraulics and electro-thermal dynamic systems. In the co-simulation approach, the multibody and hydraulics are solved within one solver, while the electro-thermal system is solved within a different solver. The communication between different solvers is performed using the TCP/IP (Transmission Control Protocol/Internet Protocol) connection. The proposed approach is implemented on a four degrees of freedom electric wheel loader. This system was modelled using the standard multibody system dynamics, lumped fluid theory, tyre model, Li-ion Thevenin battery equivalent circuit model and power transmission systems. The dynamic and electro-thermal performance of this system was tested in a simulation experiment under different temperatures of +0 °C, 15 °C and +30 °C. The results confirm the real-time computational performance of the electric wheel loader, even considering the computation of various subsystems. Further, the state of charge and temperature of the battery can be estimated during the vehicle working cycle. This study can contribute to efforts aimed at optimizing the design of high-efficiency electric machinery and developing intelligent electric vehicles through real-time simulations, thereby increasing the lifespan of the vehicles.