ACM at the AVC


Image: 1st Run


AVC was great fun and even though I went for broke on the last run and lost my copter, it was well worth it. I learned a lot about copter navigation. The latest code includes all of the updates, which is being tested now by Jack Dunkle.


Run 1 went really well. In turn 1 you can see the copter overshot the waypoint. Crosstrack error pulled the copter back to the desired path and kept it from being blown into the building from the high winds. The sonar altitude hold was working really well. Later the wind would pick up and make the copter go higher than sonar, which made it susceptible to an altitude hold bug. More on that later...

Each waypoint was hit perfectly, even though the copter tended to go too fast (17mph) and overshoot. At Turn 4 the copter buzzed the crowd at about 6 feet. Thankfully everyone ducked. Then the copter went to position hold for 4 seconds to settle down before going to land. Unfortunately this area was really windy and the copter was blown towards a tree. I had to abort by popping the copter up by 50 feet. 


At that point I thought I would try and finish the mission by landing in Auto. Unfortunately, I had set the mission to reset on entering Auto. It began to re-fly the mission at about 100ft now. It hit turn 1, then a gust of wind grabbed it on the way to turn 2. That wind was 50MPH. 


3689402904?profile=originalI was able to recover the copter this time. But the next two runs were not so lucky.




Run 2 went bad quickly. The wind shifted and lifted the copter above sonar range almost immediately. The baro alt hold bug kept it from coming back down properly. The wind above the building was gusty and blew the copter to the front of the building. Then a loose battery fell out of the copter... Because the motors were now free spinning, it auto_rotated to an upright landing from > 100 ft. The landing gear - plastic heli skids were partially broken, but it was otherwise in perfect shape. I should've taken the hint and called it a day, but run three was my last chance to finish.


Run 3:

It looked identical to run 2, except the copter kept climbing and the high winds just swept it away.



Anyway, much learned and code updated. I am trying a rate limited version of waypoint navigation. The idea is that the copter will want to travel at a certain speed towards the waypoint. This enables it to fight high winds by flying steep angles. It will also make overruns more predictable. 


Once these new updates are tested, I'll open up the code to a public beta.



Some photos posted by Mark Grennen:



Love this one:



I actually recovered the lost copter when I returned to Sparkfun this year to compete. It somehow found it's way back to me, thankfully.

The flight was doomed form the start. Once it cleared the buildings it was swept away by 50-60 mph winds. I clocked it with the GPS going up to 69mph at one point. Here's the recovered data log plotted in Google Earth.




This was very early software that was literally more bugs than good code. In fact, the morning of the race was the first time it ever flew autonomously. We've come a long way thanks to Tridge and Randy and others, not to mention the Flash SIM I built to develop the current flight management system. Looking back at this flight I'm amazed it actually worked at all.

If you've not flown the latest 2.7.3 you're in for a treat.


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  • Would be interesting to see how well GPS worked next to the building, but obviously no-one had a camera.  The thing with fine tuning waypoint algorithms & altitude sensors is you're really fighting the limit of consumer GPS modules rather than physics.  Best just to invest in an RTK GPS system.
  • Moderator


    Great Work Jason ... You are doing a Perfect Job :)

    I hope to start to work to acm as fast as possible to support your work . I Think that more powerfull cpu as our MP32 could be help you in the wind :) I hope that the next year a member of FoxTeam could be join at sparkfun avc


  • @ Jason -

    Nicely, done, I have some footage of the copter chase/search and I can share/post if you are interested.....

  • Good Job Jason! 


  • Jason great job!

    We are impatient to test waypoint navigation.... I'll make sure no trees in the area!

    Keep pushing!


  • Flying in Force  9 wind.  Sounds promising for quad navigation in high wind.  Impressive effort!

    Wind Scales - Beaufort Wind Scale, Saffir-Simpson Hurricane Scale, Wind Warnings, Fujita Tornado Sc… is your guide to boats, boating, diving, fishing, gear, marine books, marine life, safety, sailing, weather and much more.
  • Run one looks perfect. I would be surprised if your copter would have made the run at 50mph wind, thats 80km/h!

    I am looking foreward to fly your newest code, in calmer conditions.


  • Nice work Jason! You have to go for broke with the opportunity. That reminds me to tape my name and phone number to my copter!
  • Developer
    The trees do not show well on the graphics, but it was very impressive on the first run to see the copter navigate its way between the building and trees!
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