[Studies in Computational Intelligence 481] Artur Babiarz, Robert Bieda, Karol Jędrasiak, Aleksander Nawrat (auth.), Aleksander Nawrat, Zygmunt Kuś (eds.) - Vision Based Systemsfor UAV Applications (2013, Sprin

Prototyping the Autonomous
Flight Algorithms Using the Prepar3D® Simulator 227
1,2
(5) atan2 , (6)
where: – maps the landing path in the East-North plane, – setpoint
pitch angle, , , – ENU coordinates components.
6.2 Circling and Taking Waypoints
Circling command is an additional option, which starts automatically, when the
airplane is in the air, has already completed a flight along the waypoint path, and
when the user doesn't manage to give any new commands in the specified time
period. Executing this command, the algorithm is still changing the aircraft azi-
air
muth by some angle after passing a certain given distance . The whole movement is obviously on a preset height . Positions of the circular path are
calculated from the ENU
conversion and then they are converted to setpoints for
the PI controllers.
During the flight along
the desired path, which consists of a sequence of points
in LLA form algorithm uses the stabilization of the setpoint height and stabiliza-
tion of the orientation, which are calculated from designated ENU coordinates.
With this option ENU coordinates are calculated in real time, which is based only
on current and destinationn GPS position. Arbitration method for achieve destina-
tion position is the same as for other commands formula (4).
7 Tests
This paper presents four test of unmanned aircraft flights in simulation environ-
ment Prepar3D®. Thesee tests were performed on a single PC with running
Microsoft Windows 7. This computer is running two applications: simulation
environment Prepar3D®
and control application which. These applications
communicate with each other using a dedicated SimConnect library shared by
Lockheed Martin (fig. 7).
Fig. 7. Connection between Prepar3D® and control application
The first two tests weree performed to show the results of the completed PI con-
trollers tuning, and the UAV flight stabilization. Both the third and fourth test
describes the pseudo autonomous flight which is based on a sequence of geo-
graphic coordinates. The purpose of the last test is flight over the artificial traffic
on the highway, which is the first step to create a tracking algorithms.