Pixhawk Feedback?

[Old Man]

I'm a bit too far north of you to give mine a try. I'm neither engineer nor nerd so I have to take things slow and work at it a small portion at a time until I gain a solid grasp of what I'm doing. APM 2.6 was my first foray with the open source stuff and candidly I didn't have to do anything to tweak it out, the defaults worked just fine. Only some small alterations later. Pixhawk has worked out the same way, only changing some failsafe settings, and there are quite a few to address, to get everything where it works just great.

OTH, had good results with older Wookong software but the taste soured fast and forever with A-2. I'm certain the Pixhawk has the ability to mess up somewhere but so far 3dR has been on it, actually all over it once I made direct contact, with resolution for some accessory product issues. I can't say the other outfit has even tried to address the issues I had with a product that cost 3 times as much. I still feel I got bent over with that one.

Moving on, we have four Pixhawks and one APM and looking at another 6 Pixhawks for some upcoming projects. The default settings for our IR bird have been so close to perfect there has been little desire to change anything. Have I mentioned "auto tune" yet? It really does work! Or the 10 or 12 flight modes that are sitting there ready to use with a simple drop down reassignment when you connect to your laptop? Grid search? MGRS as well as Lat/Long referencing? Too many reasons to go this route. There's some pretty good info videos on YouTube that cover a lot of it. Bypass the Iris stuff although some of it can be quite informative from the FC side of things. The Ardu/APM/Pixhawk Wiki is extensive. Preferring books to video screens I printed most of it out and filled a pair of 2.5" 3 ring binders. They are not complete...

 

[Av8Chuck]

How far North are you?

 

[Old Man]

Washington/Oregon border. Bulk of the equipment is in Texas. San Diego or Berkeley and and 3dR's offices would be a lot shorter drive.

 

[R_Lefebvre]

Old Man, sounds like you're getting into some pretty serious stuff. If you're ever in need of advanced Arducopter consulting, for system integration, training, troubleshooting, or even feature additions, we should talk.

 

[Old Man]

That would be very good. If you PM. me a contact e-mail addy I'll send you an NDA so we con do some talking.

 

[Av8Chuck]

I hadn't given it a whole lot of thought until now...

Need any help doing stuff you can't tell anyone about?

 

[Old Man]

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Took a couple new birds out to dial in this evening along with my X-8 with Pixhawk. One of the new ones is a 700mm, long duration camera bird using Pixhawk, the other is, or was, a quad configuration using a Discovery frame, s800 arms, 600kV motors and A2.

The Pixhawk bird took off using default settings in the AP with the gains a little too high and twitching. Used the auto tune feature to establish tuning over the course of a flight which took about 10 minutes to complete. Landed and adjusted battery position to obtain a good balance and eliminate a rearward pitching moment that was exhibited when you hammered on the throttle. Tuned up extremely nice without having to manually go into the PID's.

Played with a couple of flight modes, the first being "Drift" where you fly it like most fly an RC plane, forgetting the rudder. Everything for direction is handled off the right stick while using the left only to control altitude. Basically push the right stick forward to go forward and left or right for directional, or roll. The flight mode slaves yaw to the roll channel so the nose is always going forward. Manual yaw is still available on demand if it's desired. The next mode was "Circle" mode, similar to POI with DJI. Toggle the switch which establishes the center of the point location and let the bird fly itself at a pre-programmed distance from the point the switch was toggle. If using Mission Planner and the radio downlink you can click some spot on the map to do the same thing. Also tried auto take off which worked great.

Which brings us to the A2 equipped bird. All went well as long as we stayed in manual or Atti mode. It flew nice and smooth like most DJI FC's do that are working well. Everything was going great until switching to POI mode to see how it compared to the Pixhawk. It made it about half way around the point before it started a sideways tumble and killed itself. Broke the frame, the gimbal, and one of the arms. The whole point of putting the A2 in the air was as a comparison against the Pixhawk. We'll never, ever use another DJI FC on any bird that has serious intent. Like all the other DJI products that did a flip of death, it waited until it was in a GPS slaved mode to kill itself.

Pixhawk is a little more work to learn and set up but it just has too much going for it to ignore because of the extra work. Plus it's only a $300.00 FC with the only addition being a uBlox GPS/compass. My GPS typically acquires great satellite count and HDOP in about a minute. Auto lands typically within 2 feet of the launch point when you test it.

 

[dazzab]

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Which brings us to the A2 equipped bird. All went well as long as we stayed in manual or Atti mode. It flew nice and smooth like most DJI FC's do that are working well. Everything was going great until switching to POI mode to see how it compared to the Pixhawk. It made it about half way around the point before it started a sideways tumble and killed itself. Broke the frame, the gimbal, and one of the arms. The whole point of putting the A2 in the air was as a comparison against the Pixhawk. We'll never, ever use another DJI FC on any bird that has serious intent. Like all the other DJI products that did a flip of death, it waited until it was in a GPS slaved mode to kill itself.

That's just horrible news. I keep reading about issues with the A2 here and I would never use one. Be careful with the Pixhawk as well. My SkyJib fell out of the sky three times with a Pixhawk just because I switched flight modes. It's a long story but they claimed my copter was underpowered. Same copter now has 50+ flights with no issues with a Wookong although I did put larger props on it. I'd love to go back to the Pixhawk but I want to use my coper commercially. It will be interesting to see how you go with yours.

 

[Av8Chuck]

It's a long story but they claimed my copter was underpowered. Same copter now has 50+ flights with no issues with a Wookong although I did put larger props on it.

Technically if you put larger props on it then you did change the power/thrust.

I've tried to constrain my opinions about DJI, people who have them love them and don't need to hear me complaining about it. But I'm very reluctant to use any DJI product commercially. I know some have with good experiences, that's just not been my experience so I just can't trust it.

I need to check out PIXHAWK, 3DLabs is only a couple of hours away, I wonder if I purchased four of controllers and took an X8 and Y6 to them if they would work with me to help set them up?

 

[Old Man]

Man, I'm sorry to hear about that, but glad I did at the same time. We'll be working through a few of these in various configs, all intended for commercial rigs of one type or another. I appreciate the head's up. We still have a couple of Wookongs and an older Naza but all are running older software versions since they have proven stable. Not as many whistles and bells but they work, and have worked all the time. GPS modes are avoided since that seems to be the Sword of Damocles with DJI flight controllers.

 

[Old Man]

I need to check out PIXHAWK, 3DLabs is only a couple of hours away, I wonder if I purchased four of controllers and took an X8 and Y6 to them if they would work with me to help set them up?

Give their help line a call and ask to talk to Vu Tran. If you don't ask you can never know. If you get Nathaly be nice. I love the sound of her voice I'll lay odds R. Lefebver would assist to some extent and I could try putting you in touch with the person that installed the one we tested tonight. You might also try asking for the old DJI USA rep when you call 3dR. He works there now. This being a pro level forum any assistance they would offer would be a nice boon in the form of free advertising I would think.

Did you receive my PM?

 

[dazzab]

Technically if you put larger props on it then you did change the power/thrust.

Of course. But being underpowered shouldn't make a copter fall out of the sky when you change modes. That was the 'discussion' I had with them. I'm pretty sure I flew with the same props at the beginning with the Wookong as well.
I _really_ wanted to contribute to the Arducopter project. I believe I'm among the first to spend so much time/money/effort testing large copters on it. God knows we need something/anything better than the crap DJI is getting away with. And the Arducopter project is very special in many ways. I think my downfall was that I actually cut my teeth on 3DR copters and Arducopter so I didn't have much to compare against except watching my friends with their Wookong based copters. Once I actually tried out a Wookong and a SuperX a few things started to make more sense about why some things were odd with Arducopter.

I need to check out PIXHAWK, 3DLabs is only a couple of hours away, I wonder if I purchased four of controllers and took an X8 and Y6 to them if they would work with me to help set them up?

That would be very cool, but I don't like your luck. Remember, 3DR only manufacturers the Pixhawk NOT the software you choose to run on it. Although they do pay a few of the guys who develop it for their time in support of the project.
My big plan is to visit Droidworx (now Aeronavics) in New Zealand and ask them for help in building up three identical large copters with three controllers for testing. They are quite a progressive company and easy to work with. Unfortunately I don't think that will happen any time soon but I'd sure like to see someone do a comprehensive proper set of tests comparing a few flight controllers on large copters. But real world experience certainly shows that right now Wookong is the preferred option. Ask those actually making a living with copters what they use. They may not be happy with it but that's what gets the results. Let's hope that changes sooner than later.

 

[Old Man]

Dazzab,

Meantt to say this earlier. Thanks for the empathy with regards to the A2 failure. I should state that it was not unanticipated, which was why the POI mode was used with both controllers. That mode works the system pretty hard and glitches will show up quick. We bought this A2 last February and it's been the red headed step child since day one. With the amount of time and effort you have to expend getting a functional response from anyone DJI you have spent more in lost production hours than the FC cost you so for all intents and purposes DJI does not have a warranty to speak of. So we pushed on with it to see how it would all finally work out. The crash was irritating since it was a fun project bird, but I suspected the odds were 75-25 in favor of FC failure.

 

[Av8Chuck]

Give their help line a call and ask to talk to Vu Tran. If you don't ask you can never know. If you get Nathaly be nice. I love the sound of her voice I'll lay odds R. Lefebver would assist to some extent and I could try putting you in touch with the person that installed the one we tested tonight. You might also try asking for the old DJI USA rep when you call 3dR. He works there now. This being a pro level forum any assistance they would offer would be a nice boon in the form of free advertising I would think.

Did you receive my PM?

I did, thanks. You obviously didn't receive my reply? I've been loading a lot of data using Box.com and it takes over my computer so I'm never quite sure if I'm sending out email whether it went or not while uploading. I'll reply to it again.

Of course. But being underpowered shouldn't make a copter fall out of the sky when you change modes. That was the 'discussion' I had with them. I'm pretty sure I flew with the same props at the beginning with the Wookong as well.

That would be very cool, but I don't like your luck. Remember, 3DR only manufacturers the Pixhawk NOT the software you choose to run on it. Although they do pay a few of the guys who develop it for their time in support of the project.

Sorry, I didn't mean to imply anything with my comment. Sometimes I read what I post and wonder what the hell was I thinking?

I have a friend who builds large heavy lift gas and turbine RC helicopters and I believe that 3dLabs sent a couple of guys to Moorpark to help him set them up with the PIXHAWK. I thought they ran a version of software that they support. I've sold about 20 medium [by todays standards] lift MR's over the past four years and recently I've been getting requests for more so if the FAA would get the hell out of the way, I can replace as much of the Chinese components as possible and find a dependable FC, I'd really start scaling my fledgling business up. Although the SuperX doesn't have the same level of functionality I was really hoping that it would work but I'm not sure they can deliver.


That's a lot of IF's...

 

[jfro]

Reading through the last 24-36 hrs of posts, I have to say, much of what is being said, I can agree to and in some instances can verify.

Currently I fly a 650 quad w/ 3520 KDE motors with SuperX. It's ok, but little disappointed for the price, they haven't had some improvements via software upgrade. It flew like crap on my 850 X8 w/ 3515's. I'm in limbo on that. I see others having success, so may have to revisit. Starting to suspect some sort of issue with gains on my knobs or xAircraft settings.

My 850 X8 now has my Naza v2 / gps on it and it flies great. Naza has been rock solid on my 450 quad, 550 quad, 650 quad, and now the x8. I NEVER take off without getting the multiple green flashes which indicates sat lock and I wait for the 2nd set. This is about 18lbs with g4 or g3. When I go to 3rd axis, it will probably be pushing 20lbs. I'm somewhat shocked that this cheap little FC does such a good job on the X8.

The pixhawk is now on my 550 and is my test machine. I lost one flight controller to what I suspect is the same issue mentioned here earlier. It fell out of the sky when I switched flight modes. Just shut off & came down when I flipped a flight mode switch. Battery was at 3.88v per cell, and still flies fine. Powered through the power module plus back up of 5v to rails from esc. Put it back together and it flies fine. Same esc's, motors, etc... Got 20-25 flights on it since the rebuild and new FC. I had just flown my first quadrant mapped flight with camera over a grape vineyard. Just a 4 minute test pattern. Pixhawk did what it was suppose to. When it returned to the starting point, it came down to about 20-30 ft height. Then paused. I let it sit for just a few seconds and switched to loiter. I then rotated it 180 degrees and then switched to stabilize (manual) to land. However to do that, because of using 2 switches for 6 flight modes, I had to travel through auto of which the pixhawk started flying towards the first way point (which it should do). As I then switched to the next position (which was either alt hold or stabilize), it powered off and fell to the ground. 3dr has had my logs for 2 weeks and still waiting on their opinion. They said it appears auto mode caused an issue, but that was first quick read.

Camera was wrecked, but quad which was easily fixed with no real cost other than needing a new Pixhawk. Thing that irritated me is the gps pole pulled one cable from gps and 1 cable from pixhawk. The gps socket on pixhawk ripped off the circuit board as the cable didn't release from socket and since they use surface mount technology, it can't be fixed according to 3dr from the photo's I sent them. From the get go, I thought the wiring connections/ size of wires was going to problematic. Didn't know it was going to be a $200 problem the first time it crashed. Have never lost a FC in a few hard landing/ crashes I've had.

My internet reading has uncovered some other undocumented Pixhawk (or maybe arducopter) shut off's (brown outs) of the power which seems to be what is talked about earlier in this thread. I will keep flying and testing the Pixhawk, but not on a bigger bird yet. The 6 position flight mode is great to use, but a concern if you need a quick flight mode change which is not in the next switch position on 1 switch. Not sure my reflexes and brain can get to the right combo quick enough in an emergency.

IMO, from reading on the different forums geared to people flying bigger rigs and doing it commercially, the Wookong and Mikrokopter seem to be the two most robust. I hope that the Pixhawk can progress so it's as reliable. The many features are hard to resist on the Pixhawk.

I have put the 3.2 beta on and the new Hybrid, which is now call position hold, is very nice on my 550 quad. I'm getting a very Naza like feel out of it. Can't compare it to a bigger/heavy MR, but hopefully it will be similar.

This is a very fluid and fast moving industry we are in. I keep buying/building based on what I think are solid / reliable parts only to find a few months to half year later, there may be issues.

Reading about crashes after 25, 30, 50 flights by experience pilots, that are not caused by apparent pilot error, is down right scary.

 

[Old Man]

I must admit the Naza is probably the best FC DJI has produced. It's relatively simple in user functionality. That may mean it fails less because there's fewer functions to fail.

 

[jfro]

I must admit the Naza is probably the best FC DJI has produced. It's relatively simple in user functionality. That may mean it fails less because there's fewer functions to fail.

Old Man. From reading your posts lately I'll take that with some influence behind it. I've found reading about all these A2 failures and DJI fly aways as well as my own experience with my Pixhawk just dropping because (possibly) a flight mode change, I find myself flying with more apprehension then before. Get very nervous flying over water. I fly with less stress when I don't read these horrow stories on the internet.

Maybe your endorsement of the Naza will give me a little more confidence in my X8. I like the way it flies and handles with the Naza and if I had a bit more confidence it would not only be less stressful to fly but maybe I'd get a little more adventurous with it.

I'm hoping that maybe next year I'll have confidence in the Pixhawk and maybe put that on a hex or x8. Wouldn't mind some more features.

 

[R_Lefebvre]

That's just horrible news. I keep reading about issues with the A2 here and I would never use one. Be careful with the Pixhawk as well. My SkyJib fell out of the sky three times with a Pixhawk just because I switched flight modes. It's a long story but they claimed my copter was underpowered. Same copter now has 50+ flights with no issues with a Wookong although I did put larger props on it. I'd love to go back to the Pixhawk but I want to use my coper commercially. It will be interesting to see how you go with yours.

Dazzab, I don't like what happened in your case for the most part, the way that it was handled. However, it is a fact that your hover throttle was ~80%, and in most people's opinions, that is too high. It's not just us. Now, DJI may effectively mask this issue from you, by artificially making the copter feel like it's not underpowered. They do this by using auto-throttle for most modes. And also limiting the pitch/roll angles and rates. Our system is capable of flying much more aggressively, and so it reserves more throttle for stabilization. This isn't a bad thing, it's just a choice.

Of course. But being underpowered shouldn't make a copter fall out of the sky when you change modes. That was the 'discussion' I had with them.

The exact issue, if I recall, is that when you changed modes, it was giving a little "jerk" as is normal. This jerk was enough to trigger the "stability patch", which reduces maximum throttle to reserve more for stabilization. The same thing would happen in a turbulent wind. If you only fly in relatively calm conditions, you won't see it. But the problem (underpowered) is still there, just waiting to bite. Whether it's a sudden gust that upsets the machine, or a motor loss on an Octo. If your hover throttle is more than 60%, then you don't have a good power reserve.

And let's be clear. "Fall out of the sky" is a bit strong of a description. It was more of a "undesired descent", as I recall.

 

[R_Lefebvre]

Sort of funny story from the weekend...

I've built a Tarot 650-ish quad that I want to use for AV with a Sony AS100V on a 2-axis gimbal. I need something simple and reliable, because I spend too much time monkeying around with single-rotors. I put KDE 2814 515kv motors on it, DJI 15" folding props, and Hobbywing Quattro ESC (nice and simple). I also use FrSky Tx/Rx in a Futaba 10C radio. I've been using this setup for 3 years, never a single hiccup.

So I'm in my back yard, just doing very initial test hovering, to get the PIDs tuned in. I'm a few minutes into that, when I notice the response getting laggy, and it autolands. Huh? I wasn't sure the cause. Battery voltage is fine, I think I've turned off all the auto-land failsafes. I don't like the failsafes in most cases, because they will suddenly autoland with zero warning. I take off again, and then this time, it goes into a full RTL. Climbs up to 30 feet, moves over 10 feet, and comes back down. Amazing because I haven't even touched the auto-throttle PIDS or anything. Meanwhile, I was madly flipping switches, trying to get back control and it won't go back into manual!

I was pissed. Actually bitched out the other devs on a Skype back-channel chat room we have going. I really dislike that it would ever lock out the operator on a failsafe.

However, after working the problem for a few minutes, I come to realize that a brand new FrSky Rx is bad! I don't know what or why, but seems like infant mortality. It worked for a few minutes, and still works intermittently. But the RTL and control lock-out I was getting is because the Rx was quiting. If I rebooted, it worked for a few minutes before quitting, and going into failsafe.

The Pixhawk did EXACTLY what it was supposed to do. The reason I couldn't get control back is because I had no control! I've never had this before, a genuine control system failure. I got interested in AV 3 years ago, and the bought my first APM system because I didn't want to fly a camera without radio failsafe. That first purchase let me down this rabbit-hole with Arducopter, which is now becoming my second career. Here I am, 3 years later, I've never been paid for an aerial video. But I finally had justification for going down this road. I actually replaced the Rx with a 3 year old one, the first one I ever bought, and it's working perfectly.

Anyway, point is, when the system doesn't do what you think it should, even the most experience person can get confused. A lot of people jump to blame the system, when there might be another external cause for why the system did what it did.

 

[dazzab]

And let's be clear. "Fall out of the sky" is a bit strong of a description. It was more of a "undesired descent", as I recall.

Yes, that's true. Enough to cause a lot of damage to my gimbal though. And why did it take three events before this was noted? I flew that copter with a dummy load several times without issues. We also determined that auto tuning it with the payload may have contributed to it as well. And let's not forget how poorly I was treated over the incident. No user should be treated like I was. So, it's not just one incident that I based my decisions on.

To also be clear, this series of three events was not the only incidents I had over time with the APM/Pixhawk. There were numerous others. Remember, and it's documented in release notes, it was my copter that found the problem with the code not working correctly when the barometer became hot to mention just one. Yes, that was fixed immediately and users were warned which is great. But how many people crashed because of it? We will never know.

I maintain that based on my experiences, Pixhawk/Aruducopter is not at this point in time the best choice for commercial use with large copters. I see it more as a research project by some extremely talented/smart people that has led to a fantastic flight controller. It's always pushing the envelope which is very cool, but not what you need when you have $10,000 of gear in the air. There are others who disagree and who have had better experiences. That's fine. When it comes to flight controllers we all know that YMMV and different people find different flight controllers meet their needs.

On a more interesting note, due to removing a few Pixhawks from my copters I now have a few spares sitting around. Of course, they are the only way to go for planes so I can use two for that. But I've decided to build a 250 size copter for one of them. I think it will be a lot of fun to have such a technically advanced copter that's not that much bigger than the flight controller itself. After spending a few years with these larger copters, which I'm now using to film rather than spending a lot of time on the bench with, I'm really looking forward to a little FPV speed demon zipping around the place. I might even try some acrobatics. Yet another fun adventure in copter land.