Long autonomous mission

Long autonomous mission

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Its been a while since I have some time to post in the blog. But with great powers come great responsibility hehe…

In this post I’m going to describe the process I did for the mission that was showed in the next video:

That was one of the longest autonomous missions I have done with a quadrotor. The vehicle travelled approximately 6.2km and the furthest it went from the operator was 3km. I decided to make this mission just to see if the vehicle was capable as well as the extra systems that accompany the vehicle.

The vehicle was also somewhat new, I build it and flew it 5-6 times before attempting this mission. The motors were great (4114 pro), I was using cf tarot foldable propellers and a modified cf frame.

Foldable quadrotor

These combination of components made a very efficient yet powerful vehicle, with an 5.2Ah battery, the vehicle was flying around 24min.

And as usual this vehicle contain the AltaX flight stack, which is just the combo of a companion computer and a flight controller. The companion computer is the Raspberry Pi 3, while in the flight controller I chose a pixhack. The pixhack is a version of the standard pixhawk but the IMU has internal dampening, which means not too much vibration isolation is needed, this was specially key in this frame as it does not have too much space…

Also in the communication side of things, I added a high-gain wifi dongle dual band. Such wifi dongle is powered using a BEC because by itself the rpi cannot supply enough power to have a decent range.

For camera, I was using a gopro hero 3, therefore the hdmi-csi bridge is needed. The gopro was mounted in a 3 axis gimbal, the tarot one… excellent gimbal for the gopro.

In the ground I had a directional AP that was always pointing towards the vehicle, that AP was connected to my computer using an ethernet cable therefore the network was complete. The AP I had was an Ubiquiti Loco M5, which had a great range!

So, the rpi was in charge of talking to the pixhack (via mavlink using dronekit), also running the AltaX Ground Station Console and finally transmitting the video back to the ground (video stream server).

For the video transmission, I used very similar techniques as in here. So, I was using gstreamer. The hdmi-csi bridge basically turns any hdmi device into a v4l2 device… so, it was very easy to pipe it using gstreamer.

My ground station console is basically like a pilot remote with extra power 😉 It is capable to send any kind of command to the pixhawk, like take off, change altitude, circle around, send a mission, manual reposition… you name it!

I chose the Scottish highlands as place to test this mission, because the remoteness of the place, I had no problems with regulations, since there is nothing around… even so, I followed the regulations in place in the UK.

The mission started by me taking off the vehicle, leaving it in loiter mode, then checking the console tool, upload the mission and start it with an enter. That sweet. Then after 17 stressful minutes, the vehicle was in sight… it was coming back, in either case, the telemetry was telling me where it was… let me say something, this loco m5 is quite a nice product!! I never reached half of the connection strength!

The main problem was at the end, the vehicle was flying head wind… therefore the motors required more juice in order for the pixhawk to maintain 5m/s… but at the end with the alarms making beep beep beep beep.. I was able to perform a somewhat hard landing. But everything was ok and the mission was successful!!

I would like to say sorry due to the low resolution of the screen recording… what happened is that I lost the original file and I only got this less-than-HD version… yuck.

In any case, I hope you enjoy the video, extra thumbs up to the person that recognizes the soundtrack!

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