RFlySim: Automatic test platform for UAV autopilot systems with FPGA-based hardware-in-the-loop simulations

Autopilot systems on unmanned aerial vehicles (UAVs) are safety-critical systems whose requirements on reliability and safety are ever-increasing. However, testing a complex autopilot control system is an expensive and time-consuming task, which requires massive outdoor flight tests during the whole development stage. This paper presents an indoor automatic test platform for autopilot systems aiming to significantly improve the development efficiency and safety level of UAVs. First, a unified modeling framework is proposed for different types of aerial vehicles to make it convenient to share common modeling experience and failure modes. Then, a real-time simulation platform is developed by using automatic code generation and FPGA-based hardware-in-the-loop simulation methods to ensure simulation credibility on software and hardware levels. Finally, an automatic test framework is proposed to traverse test cases during real-time flight simulation and assess the test results. In the verification part, the accuracy and credibility of the simulation platform are verified by comparing the obtained results with experimental results, and several successful applications on multicopters demonstrate the practicability of the proposed platform.