MAJOR CS8 HL/MK FAILURE!! Help please! Hey guys, I had an extreme failure yesterday that led to a semi controlled crash. The FACTS: I was flying in an OPEN field. I flew two batteries for 8 minutes EACH, about a one min break in between. Batteries checked each time and were at 99% and each cell almost exactly the same. About 1 minuet into my 3rd Battery, I was just hovering for a few seconds looking at the sunset and the copter begins to bank right and increase speed. Then bank left and increase speed. It began a about a 6 minute battle between myself and the copter making LARGE circles, fighting me every step of the way. The below has nothing to do with the issue but I just wanted to give all the info. I eventually turned Altitude control off (near the end of the battle) and I think I switched COME HOME on. I gained semi control and brought it into a bushy tree. The Details: Copter: CineStar 8 HL (http://www.quadrocopter.com/CineStar-8-MK-Heavy-Lift-RTF_p_1156.html) Gimbal: MoVI M5 Camera: 5D MK III w/small 20-35 canon lens Battery: 10000 6s 22.2 V Battery Take off with GPS and Altitude hold OFF, then SWITCHED on after takeoff Satellites Approx 8-10 Satellites at takeoff Weight Approx Payload weigh: 8.5lbs Exterior temp: 77degrees farenheight Wind: 1-2mph max Time: 7:45pm EST Amazingly I only lost one blade, and nothing else.. I know everyone will say why didn’t I turn GPS off, and that’s a GREAT question.. I WAS TERRIFIED! I wasn’t sure if that might have been the only thing holding it in the air? ALSO, when you look at the GPX File, it all seems FINE! QUESTIONS: - WHY?? - If it is the GPS, why have a GPS that could with no notice go crazy.. I know you should know how to fly manual and I DO, but I like GPS mode! (at least I did) THE VIDEO: CS8 HL Failure on Vimeo PASSWORD is: crazy CRAZY starts at about 2:36 The commentary at the end is by me THE GPX File is attached. Please help decode this mystery!! Thank you! - - Justin
Hi Justin: Did you notice these: Errors / warnings: Error "Motor restart" (23) occured 7 times! FC-Flag "LowBat" (5) occured 34 times! FC-Flag "Failsafe" (2) occured 1 times! So what's going on with the Motor restarts, and the Failsafe? I'll look at the GPX data in more detail, so this is just a quick look. Andy.
Hi Andy! I noticed them but they seemed to only appear later in the flight way after the shit already hit the fan..
Justin, First of all, you did a great job keeping a cool head. I’m sure this was terrifying! And from the looks of it, you didn’t have very many open spaces to set down in. I don’t like flying over neighborhoods like that for just this reason. But let’s move on. I saw nothing in the GPX file that changed when the copter starting pulling big current and meandering around. I have had a couple things happen like this, the worst of which caused my copter (an X8 coax) to spin out of control in the air one way, then the other. But I got it home. What happened to me? One of my pairs of motors came loose on its boom, causing the pair to rotate slightly one way, then the other way. The GPX file showed nothing, as the copter couldn’t know. My theory is that something came loose on your copter. Things to check: Did one of the motor mounts come loose? Grab each of the motors and twist it and see if it rotates at all from vertical. Did the flight control board come loose? If it was to come loose, it could cause this kind of problem. Similarly, did the altitude sensor come loose? That’s less likely. Lastly (and this is what I think happened), did the MōVI come loose? Any number of things could happen that would throw the copter’s balance way out of whack, like the down bar sliding back or forth, or slipping side to side. Again, nothing would show up in the GPX file, as it wouldn’t know, but the copter would have a heck of a time maintaining flight in that situation. Anyway, hopefully you can get to the bottom of this. Good luck!
Steve this is where the plot thickens.. First of all OMG IT WAS TERRIFYING!!! After getting it back within 10 minutes I got heart burn, something I NEVER GET!! The copter, motors, cables, etc were all tight and pushed in.. After watching the video a million times I'm noticing it begins to "toilet bowl" Early! The MoVI did some odd stuff, but only after the copter started to spaz out.. Honestly if it goes off balance I would expect the motors to compensate and fight.. Not give up and start to haul ass in a ridiculous way. When you watch the video - it was just hovering and then it takes off.. It was not a gradual thing.. It was severe. I had to compensate by giving full throttle in the opposing directions.. When i inspected the copter after the incident, I was expecting something to look off, motor cocked, etc.. I saw NOTHING! The copter was in near perfect condition except for a cracked propellor from the impact. I hope someone can make sense of this. It's very disconcerting that there are no arrows pointing to any possible cause..
Just FYI the CS8 is amazing.. Freefly has nothing to do with this! They are just the skeleton, the brain is what's the problem right now.. The CS8 frame is probably what saved this from being catastrophic.
Justin: Hmm. Look at row 272 and check the GPS Sticks (which is the GPS autopilot), it's starting to put in some serious deflections on the right stick. And it continues to do that for quite awhile. it looks like the Position Hold has malfunctioned big time. The copter still had 9/10 satellites. The solar weather looked good at the time (according to n3kl.org). So the answer would have been switch to all manual flying. Even using Come Home is a bad idea because it depends on GPS. What's harder to answer is what to do about it -- but it certainly looks like something is very wrong with the GPS/position hold based on the stick inputs in the GPS Sticks column. Never seen the like of it. Andy
Oh, by the way, the motor restarts can be ignored. I think they were "arboreally induced." But the more I look, the more the GPS Sticks column seems to be the culprit. Steve: what's your take? Andy.
Steve theories are good and I think Justin should check closely the FC again but After trying to trouble shoot with Justin yesterday and today and not finding any strong theory of why a standard hover in PH and AH suddenly became what it look like a big toilette bowl I wanted to ask are there other ways that a copter suddenly gets in to toilette bowl behavior? perhaps a unseen outside influence?
Other puzzlers: 1. What caused the fail safe at row 534? 2. Even with Coming Home enabled (row 555), the GPS sticks are still showing lots of inputs. 3. Rows 540 and on -- there are numerous SPEAK_GPS_FIX that suggest the copter was losing the GPS fix -- which is distinct from the number of satellites its receiving -- it's the actual GPS fix in three-space. Did you hear Fraulein Graupner talking to you? My instincts are still saying it was something to do with the GPS/autopilot. The motor currents are very erratic, but that's a byproduct of the autopilot going rogue, I think. Andy.
Yup -- if the copter loses its GPS fix it suddenly doesn't know what PH means! Which position is it in? Andy.
By the way, for Firmware 2.02 there is this: (since NC2.00f) If the MK starts without GPS-Fix, ComingHome was disabled. Now the Position for CH is the first GPS-Fix in flight -> in most cases that is close to the starting point and better than not coming back See http://www.mikrokopter.de/ucwiki/en/Firmware-2.02#GPS So, imagine the copter loses its GPS Fix in flight for whatever reason, with the new firmware, if you turn on CH, it will "update" the come home point to be the last GPS FIX. In this case, it looks like there were several in-flight GPS Fix announcements (which I believe means it has *found* a new fix). This implies it must have lost the first GPS fix it had before it took off. I have a sneaking suspicious that the 2.02 firmware may continue to update the "home" position more than once in flight -- and, as you discovered, that has ghastly consequences as you are now fighting the man in the machine and "home" keeps shifting. Andy
Good piloting! Motor restart errors are just so annoying. What are your motor timings on Bl ctrl 3.0?
I was looking at the map view -- are there any power lines, cell phone towers, any other transmitters nearby that could interfere with the GPS? Anyway, the universe is telling you that it's NOT a good spot to fly there, I suspect. Andy.
What type of things can cause the loss of a GPS fix during flight with plenty of satellites? Would this relate to Steve's idea of something coming loose? Is it the sign of a failing GPS module or just something that happens when the satellites connected are all near the horizon or in bad positions? Nice job getting it to the ground without a lot more damage to the copter, the area or to people. It certainly could have been much worse.
Michael: Radio interference from local sources can drown out the GPS signal. I was out in the middle of the Alvord Desert in SE Oregon last summer. 16 satellites. No GPS fix. I tried a backup GPS board. 16 satellites. No GPS Fix. I called Gary on my cell, no solar storm. And then suddenly, after two hours, when I was just about to abort the day's shoot, I got a fix and had no problems for several days. For the conspiracy theorists: Now whose government might have been creating radio interference out there, you wonder? Andy.
Wow, lots of great feedback here.. There were definitely power lines in the area.. The thing that baffles me is that I flew for at least 16 minuets in that area with no problems. Thanks for the kudos in piloting.. It was really so terrifying I can't explain.. Not being able to trust the GPS is a very bad thing and makes me very confused.. I fly my DJI phantom in this area and NEVER have had a problem. The following link is footage from the first two flights.. Bang on perfect stability and hold..
But let's say that's the case.. I didn't hit Come home until LATE in the flight.. I actually think that's what gave me some sort of control back oddly.
Andy, I remember you posting about that...so am I following the concept right that you can have satellite connections to the GPS but be unable to get the satellite data required for a fix? Basically radio interference can drown out the data but not the fact that the GPS has connections?? Did you ever get any more of an answer to having 16 satellites in the middle of nowhere without being able to get a fix? That is really puzzling. Justin: I'm guessing you were flying the Movi in a remote operator set up and took off in kill mode and activated the movi once you were flying? Was someone else running the movi? I do not recall much camera movement (but was really focused on the booms passing in front of the lens) which makes me think Majestic mode, but if that were the case it would have panned when the copter was yawing. Do you remember if you were giving the yaw commands when it was out of control (maybe trying to get situated in a tail-in position) or if it was doing that on its own? A couple times when I saw the booms they seemed to be yawing quite a bit. Do you have the care free flying mode on a switch on your transmitter? Do you use different brands of receivers and radios for flight control and gimbal control? What seems hard to explain as I am typing this is the fact you said you had 2 uneventful flights prior to this one...which seems to rule out the location, power lines, etc (unless there is something large that was switched on during the last flight...but pretty unlikely). I only have GPX tools set up on a laptop PC which is packed away at the moment so I have not looked at the GPX file yet, but I'm wondering if the files from the prior 2 flights may have any clues in them or brief warnings that never got to the same crazy level of your last flight. I would be happy to look at them sometime tomorrow if you want to upload them - and maybe someone else may be able to look at them sooner to see if there is anything helpful.
Have a look at the GPS sticks inputs in the GPX file, though....it was really putting a lot of inputs in... Also, why all those "SPEAK_GPS_FIX" messages? I think it was losing/regaining fixes. Andy.