Hardware-in-the-Loop Simulation and Testing

Distributed Autonomous System Laboratory

Hardware-in-the-loop Simulation

Project Description: 
Flight-testing is critical in providing confidence in the reliability and effectiveness of UAS autonomy algorithms in real-world environments. However, federal regulations, and the cost of flight-testing in general, can make it difficult to engage in an extensive flight testing campaign. 
To address this issue, the DASLAB utilizes Hardware-in-the-Loop (HITL) simulation architectures. HITL simulations are designed to tightly couple flight computational and sensing hardware with high-fidelity physics based UAS and environment models to create a graphic and highly realistic virtual flight-testing environment. Through HITL simulations, researchers can test the software and hardware systems in a low cost and zero-risk environment before engaging in costly flight-testing. 
Stabilis Communication Diagram
We have demonstrated that off-the shelf, and very low cost gaming platforms, such as Laminar Research’s X-plane flight simulator, can be utilized to quickly create usable HITL simulation environments. Our simulator also utilizes off-the shelf computing and communication platform to enable real-time simulation capability.This approach requires development of simulator to hardware interface drivers, but alleviates significant amount of effort and cost required in developing graphics interfaces from scratch.  In our setup, X-plane communicates with the onboard autopilot (Stabilis) through UDP protocols, and the autopilot communicates with the in-flight Ground Control Station through a 900MHz wireless radio link. 
Our HITL simulation has been extensively validated. The high fidelity flight models employed are highly accurate, to the point where we have shown that control gains tuned in simulation do not need to be re-tuned during real-flight testing. The DASLAB HITL simulation environment is currently being used for validation of onboard control and autonomy software, as well as UAS related outreach and education.
Jacob Stockton initiates a HITL test on DASLab’s early HITL simulation setup.