Closed-loop platoon simulation with cooperative intelligent transportation systems based on vehicle-to-X communication

Abstract

The continuous enhancement of X-in-the-Loop (XiL) simulation methods is one key to efficiently test advanced vehicle control functions and ensure high software quality under a rising cost and time pressure. Systems, which control vehicles based on sensor perception can already be evaluated in XiL simulations. However, future vehicles will not exclusively represent stand-alone systems anymore, but involve Cooperative Intelligent Transport Systems (C-ITS), distributed among different traffic participants. While several simulation environments for C-ITS feasibility studies are available, common virtual test frameworks cannot incorporate multiple interacting and communicating road users with the required fidelity to secure C-ITS software, e.g. for platooning applications.Within the scope of this publication, a method for virtual testing and calibration of in-vehicle C-ITS using a high fidelity vehicle platoon model is presented. Multiple closed-loop controlled vehicles and the mutual interferences between them are simulated in a common 3D environment alongside other traffic. Each high fidelity vehicle model individually simulates the longitudinal and lateral response, the generation of sensor data plus the exchange of vehicle-to-vehicle data. As a proof of concept, a model-in-the-loop simulation for a Cooperative Adaptive Cruise Control (CACC) was conducted. The simulation environment included five high fidelity vehicle models forming a platoon, coupled with CACC controller models under test.The results reveal that the developed simulation environment captures the interaction within collaborative vehicle groups while modeling individual vehicles as controlled systems in the same tool. At the same time the method satisfies all requirements for XiL testing. Functional tests of multiple interacting vehicle controllers have been successfully carried out. In the performed feasibility study simulation-based tests uncovered an insufficient control stability of the CACC. Upcoming series developments and homologations of in-vehicle C-ITS software and hardware can be supported by the new virtual test environment to overcome connectivity, reproducibility and cost efficiency limitations of physical test environments. Next steps include proving the method in use for series development and extending it to cover vehicle-to-infrastructure use cases.