Hardware in the Loop Testing of CAV App

completed

Most existing studies on connected and automated vehicle (CAV) applications apply simulation to evaluate system effectiveness. Model accuracy, limited data for calibration, and simulation assumptions limit the validity of evaluation results. One alternative approach is to use emerging hardware-in-the-loop (HIL) testing methods that allow physical test vehicles to interact with virtual vehicles from traffic simulation models, providing an evaluation environment that can replicate deployment conditions at early stages of CAV implementation—without incurring excessive costs related to large field tests. In this study, a hardware-in-the-loop (HIL) testing system for CAV applications is proposed. The involved software and hardware includes CAVs controlled in real time, traffic signal controllers, communication devices, and a traffic simulator (VISSIM). Such HIL systems increase validity by considering the physical vehicle’s trajectories (as constrained by real-world factors such as GPS accuracy, communication delay, and vehicle kinematics) in a simulated traffic environment. Specifically, the platform creates more realistic testing environments (e.g., background traffic, imperfect/varied sensor and wireless communication performance) to be able to attain more accurate expectations of the application effectiveness compared to simple field tests using a limited number of vehicles and no background traffic. The developed HIL system is then applied to test two representative early deployment CAV applications: queue-aware signalized intersection approach and departure (Q-SIAD) and cooperative adaptive cruise control (CACC). The experiments successfully demonstrated the functionality of both the vehicle-to-infrastructure (V2I) and vehicle-to-vehicle (V2V) testing architectures, with one test CAV driving through one intersection controlled by a fixed-timing traffic signal and one test CAV platooning with other virtual vehicles under various simulated traffic conditions. Lessons learned and future research directions of HIL testing of CAV applications are also discussed.