Orbital Trajectories#
Moved here from https://github.com/nervosys/AutonomySim/wiki/An-Orbit-Trajectory
Have you ever wanted to fly a nice smooth circular orbit? This can be handy for capturing 3-D objects from all sides, especially if you get multiple orbits at different altitudes.
The PythonClient/multirotor folder contains a script named Orbit that will do precisely that.
See demo video
The demo video was created by running this command line:
This flies a 10-meter radius orbit around the center location at (startpos + radius * [0,1]). In other words, the center is located radius meters away in the direction of the provided center vector. This also keeps the front-facing camera on the drone always pointing at the center of the circle. If you watch the flight using LogViewer, you will see a nice circular pattern get traced out on the GPS map:
The core of the algorithm is uncomplicated. At each point on the circle, we look ahead by a small delta in degrees, called the lookahead_angle, with the angle computed based on our desired velocity. We then find the lookahead point on the circle using sine/cosine and make that our target point. Calculating the velocity is then easy; just subtract the current position from that point and feed this into the AutonomySim method, moveByVelocityZ().