3D Robotics

3689601960?profile=originalCongratulations to Leonard Hall, whose incredibly fast ArduCopter (shown above) won the Sparkfun AVC copter category, and Philip Rowse, whose ArduPlane did the same in fixed wing. In rovers, my own ArduRover came in first in the micro rover category, and there were Pixhawks and APMs throughout all the other categories and contestants. A fantastic day! 

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  • Wow so many crashes !

  • Developer
    The point missed in the above analysis is that the Pixhawk has a brilliant redundant power system. It requires a primary power to be supplied to the Pixhawk at 5.3v, and can take a second supply from the servo rail up to and NEVER above 5.7v.

    Powering ANY autopilot via the servo rail is NOT recommended, unless it is a backup supply only, and must have protection supplied to protect from digital servos putting spikes above 5.7v on the rail.

    under NO circumstances should the servo rail be used as the primary supply.

    Roberts comments about cause are critical here, we know exactly what caused the Heli crash at AVC due to the onboard BLACK BOX that is the Pixhawk, without the autopilot onboard, similar could hav occured, but investigating this without the BLACK BOX would not be possible.
  • Yep.  That is why I generally just avoid the whole mess and use a 2S LiPo with HV servos.

  • Even name brand BEC's are risky unless you pay close attention to the small print. When the package says "20A" that means "20A peak". It's only good for 10A continuous at best (and personally I wouldn't trust them for 10A continuous).

  • Ankle Biter (running APM 2.6) took 3rd in the Micro/PBR! 
    During morning testing, my V+ to my sonar severed about 30 minutes prior to the first run. The APM took the unpowered sonar as it detecting an obstacle, so all it wanted to do was turn right (right into the fence for 0 points that run). Luckily, I did spot the issue and fix it soon after, so the 2rd and 3rd runs went perfectly. You can see my 3rd run here:

    https://www.youtube.com/watch?v=DoMJyez9nBg&t=3h04m18s

  • It was difficult to judge from the video, but there were at least 3 crashes that made me fairly nervous, with the 550 Heli crash you mentioned probably the one with the most potential for harm.  Did they move the crowd back after this one?

    Nope, of course they didn't change anything.  They just laughed about it.  Safety is a joke at AVC.  I was one of the very few who understood the risks with that 550, and I was hiding behind a table during the flight!  Everybody else was blissfully ignorant.  

    Why do you suppose there have been so few incidents involving big helis and crowds at all the big 3D etc. events? It's maybe because of the combination of pilots who have excellent manual flight skills and fine, generally mature equipment that has been properly set up. No newbie pilots relying on an autopilot, no Brand-X parts from some unknown dirt-floor factory in China, nobody stupidly overloading their BECs. The airframes, power systems and flight controllers we are all playing with are all still highly experimental, in comparison, and anything large (say 450 and up) really has no business being flown anywhere near people, let alone crowds, unless the crowd is behind a net.

    This is actually a fairly interesting comment for several reasons.

    First, I think the reason why there haven't been any spectator incidents at 3D heli events is because they are organized properly, and they have a sensible location for the spectators.  

    Second, it's certainly not true that 3D heli pilots are perfect, nor are the machines, if you consider the rate these guys are killing themselves, getting hit by their own helis.  Think is though, we never know what the *cause* of the crashes are, because there is no data, and that community is interested in learning why anyway.  Any attempt at an investigation is met with a "Dude, it's not right to blame the pilot.  It was a freak accident.  He died doing what he loved.  Think of his family."  Compare that to this situation, where, within 15 minutes we knew with high certainty exactly what the cause was. 

    The comment about the equipment in use is particularly interesting.  That 550 was a high-quality kit, using good name-brand electronics (including the BEC).  Brownouts using this equipment happens all the time, and is NOT only a problem with the Pixhawk. Though the Pixhawk may be more vulnerable, it is possible to almost completely eliminate the problem.  I've been doing this for 3 years and have NEVER had a brownout.

    I do use mechanics from various sources.  Some of it is good, some is not.  It's an economic reality of developing this code that you need to try to keep costs down.  And you can't figure out what is good or not without testing.  And the idea that simply paying more for name-brand is going to guarantee you good mechanics or electronics is totally wrong.  Lots of the top brands still make junk.

    However, I knew that the heli I brought was NOT mature enough, and chose not to fly it even after I fixed the yaw problem, even though it might have been just fine. Some people think I'm overly cautious, but that's how I operate.

  • Bad luck Randy but awesome work and it will definitely benefit the wider community in the near future.  There are endless uses for vision and the new guided modes, in particular I'd love to see vision based landing (like automated landing/RTL on a moving boat, for example).

  • Admin

    @Chris,

    Actually I came in 7th, but the scoring was fairly close between the 3rd and 7th places.

    If I had not had the Start/Stop problem on the 2nd run, I probably would have made 2nd place.

    Also, our team was under the impression that you had to run the barrel chicane for points and that is not the case.

    Running the barrel chicane slowed us down considerably.

    Next year we will bypass the barrels and run straight from the first corner to the second corner between the barrels and the inside of the course.

    Based on my 8m/s third run first place finish, I believe that we can be very competitive next year running 9 - 10 m/s in the straights.

    Getting lined up for the hoop and the ramp during practice worked for us, but during the runs, we had no success with either, but in many cases, neither did anyone else:-)

    Regards,

    Tom C 

  • Not positive if that is the crash that I witnessed, however on takeoff a quad flew directly toward and just a few feet above the sitting crowd and into people standing near the top of the hill. About 15 feet from me. Fortunately, they all were able to move out of the way before the quad hit the ground. Good thing the two EMTs nearby didn't need to take action.

  • The competition was a bust for me.

    I built a 500 helicopter specifically for the competition, but had a series of crashes during development.  I never finished getting if flying properly, and hadn't done any auto runs with it, ever.  I brought a whole stack of parts to the competition and hoped to find enough time on Thursday and Friday to get it working.  That just didn't work out, with Friday being pretty much a write-off because of DroneCon.

    After DroneCon, I headed out to the field.  I had a major problem with yaw control, which had actually caused my last crash while testing at home.  I spent several hours trying to work on the settings, checking the code...

    Eventually I gave up and took out my backup machine.  The 450 heli I used last year which works flawlessly.  I started testing it, and it was going fine.  But on my second flight, an unfortunately combination of problems led to it crashing in the lake.  It's lost.  It was not a problem with the code, but a pilot error, largely caused by lack of sleep, and not using my normal transmitter setup:  I flicked into Acro instead of Stabilize, rolled it upside down and powered it right down into the water.  Almost took out a stork.

    So that was the end of that.

    On Saturday, I kept trying to figure out what was wrong with the 500 Heli.  Eventually I realized that the problem with yaw was not the code or parameters at all!  It was one of the few HobbyKing parts left on the heli (started out with the HK500TT kit, but there's not much original left on it now).  I had actually brought some genuine Align parts and swapped them out.  The tail now works perfectly, but it was too late to fly in the competition.

    The 550 Heli that crashed was Ray Gamero's.  It was a pretty scary event.  Post crash analysis indicates that he mostly likely had a brownout due to powering the Pixhawk from the same BEC as the Servos.  Hopefully Sparkfun takes my advice next year and limits the allowed size of helis.  This could have ended very very badly.  The damage done to the chain link fence is indication of that.  By some miracle, the heli landed in one of the few places which didn't have people around.

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