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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  • Jason in order to prevent way point over shoots would it be possible to put in a way point short of the corner then another on the next heading you fly up turn 45 degrees intercept the next heading then turn 45 degrees again  on to the next heading rather than fly right up to the way point and hang a 90 causing a over shoot . on a large plane with no traffic we start cutting  across the corner sometimes 15 to 30 miles back to the next heading .If we flew right up to the way point at 500 knots and hung a 90 if the wings didn't come of 1/2 the passengers would loose their lunch the other half their "Bowels!"  Ideally we like a inter sect angle of 30 degrees or less . Unless you slow down and stop at the way point you have hoover capability ! Just an idea  It is Excellent what you have done!Glad you got your copter back Have a great Day!

  • Developer

    Weird that this showed back up in the main thread. Sorry about that!


  • Sadly, all we had was a line on the heading, which was (from memory) 155 degrees. Its amazing how you lose depth perception of a small object like that in the air, theres really no telling how far it was form Sparkfun at the time it went down.=-(
  • might think so....but it was actaully an onboard data logger. Notice the missing data from the last flight?
  • wouldn't he have to have an XBee on-board to get those tracks shown above?
  • It's too bad Jason didn't have an X-Bee onboard. We could have been recording his telemetry and possibly located his lost bird.
  • Well done Jason

    I would have loved to have been there to see the action.

    The 1st run looked very impressive and I guess lessons have been learned from run 2 and 3.

    It is all a great fun learning curve I reckon.

    Can't wait for the new code release - flying in 50mph (80km/h) winds was a bit ambitious.




  • Developer

    Gratz Jason,


    Next thing what we need to develop is homing beacon :)


    I sure hope that I can come on next year too.In mean while we need to build a lot of quads/hexas so we can fill whole sky on next AVC


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  • Nice work Jason, sorry you lost your Copter! It was nice meeting you and all the guys from DIYdrones, uDrones, UavDevBoard and Sparkfun! It was a lot of fun!
  • Developer
    Congratulations Jason!  leading edge stuff!
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