Real-Time Controller Architecture for sUAS Flight Test

Flight test of experimental controller designs can be difficult when using commercially available hardware on small unmanned aircraft systems. The supported software often relies on specific messaging protocols to send commands to the aircraft which can vary significantly between controllers. Furthermore, modification of an existing package to accept different types of controllers can prove to be a difficult task. This paper details a real-time control architecture for small unmanned aircraft systems, named Kanan, capable of safely and quickly integrating a variety of flight controller designs on a various platforms including fixed-wing aircraft and rotorcraft. Kanan is a C++ based software package which supports command authority using RC channel overrides, attitude control, and both local and global position control. The Robot Operating System and MAVLink messaging protocols are fundamental for how messages are shared between an Ardupilot flight stack and onboard companion computer. Additionally, the framework provides support for pilot operated safety measures and the ability to perform common flight test maneuvers, such as doublets or sawtooth climbs, for further control system and vehicle analysis. A low-barrier to entry is achieved by restricting all necessary changes needed for various tests to only two files and including a graphical user interface to reduce the required experience to operate the ground station computer. Testing and development of experimental flight controllers with Kanan can be done more quickly and significant changes can be made to the control design without having to modify or sacrifice existing data logging and safety functionality.