Powertrain Model In The Loop:Virtual Vehicle Simulation Based On FMI Standard

At present,the automotive industry in new products development cycle has two big changes.Firstly,since the complexity of dynamical and control systems have continued to rise and time as well as budget applied on development are limited,transferring the system validation phase to early development phase and applying the Front-load method instead of physical tests to improve development efficiency have become the industry consensus.Secondly,the trend of global economic integration enables partners from different countries and regions to work together to complete tasks assigned by carmakers.Development process include not only the actual components and systems but also the early development of simulation model of parts.Since different development teams may select different simulation software for model building,plus different modeling and simulation software has its own model and data storage format,it is necessary to define a general model of interface between different software.To follow up the research orientation in industry realm abroad,this paper focuses on powertrain model in the loop and study whether it is feasible or not to build virtual vehicle model using three different software based on FMI protocols.Firstly,the GT-POWER engine model was built.Steady-state and transient calibration methods were applied on that model to verify its accuracy.The method that enables GT-POWER origin model to transfer to fast-running model was discussed.Secondly,the transmission system model was built via SimulationX software.This model includes 6-speed DCT and reducer.dSPACE ASM model library was used to build vehicle dynamic model.Then the co-simulation method of Simulink,GT-POWER and SimulationX based on FMI standard was studied.The idle speed control module and TCU module were set up in Simulink environment.Three models were connected by FMI interface,and the step size of each co-simulation module was also discussed.Finally,simulation results were compared to and analyzed from the result of a real car on the roller test bench.The result shows that the simulation curves of key performances(i.e.fuel consumption,torque,speed)of the powertrain model is almost the same as that of the real vehicle.This results indicate that:the model-in-the-loop simulation has a highly pragmatic value in the early phase of system verification and validation.This method is able to detect possible problems in vehicle systems and modify requirements in advance.This work prepares for the following Hardware-in-the-loop test.