I've got a stock 3dr kit that I've just finished putting together, and it tries to flip on takeoff. I'm running x config. Arducopter 2.1 firmware.
I've run through the troubleshooting steps: checked motors with the cli motors command (successfully), made sure the correct props are on each motor, calibrated the radio and verified that the correct inputs are reaching apm, but I still cannot get this thing to take off or fly at all correctly. Apm is facing forward between the front legs, and the movements seem to show up correctly in mission planner when I move the quad around while connected to it.
If I give it a smooth throttle increase, it won't take off flat, it will just tip, so I back off the throttle. If I give it a burst of power, it will take off, but will dive off to one side and crash (just busted my first prop...)
I've run the imu test with the following results:
g 0.0209 0.0000 -0.0000 a -0.1157 -0.0463 -9.8016.
I have downloaded logs from the last couple of flights where it was tipping when I tried to take off, but I can't figure out how to interpret them. If anyone could give me a quick rundown of the best way to view/read them that would be good. I have attached the log.
Are there any other diagnostic checks that can be run to find out what's going on? I saw another thread where someone was checking the watts of power delivered by each esc to each motor to verifiy that a esc/motor not running at full speed wasn't to blame, but I'm not sure how this would be done.
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I have just emailed help@3drobotics.com with info.
Thanks for your help.
Thanks for that Pat, I did come across your page before I started with my build, so did take your advice into account. I have got all of my ESC's connected to the correct wires on the PDB, but did have to cross the motor connections to the ESCs over the PDB for motors 3 & 4.
So for my issue. I'm still finding that when the quad is sitting on a flat bench, that the compass and roll sensors will constantly move, which ends up with the quad showing that it is constantly spinning in the mission planner, when it's sitting stationary. Is this indicative of a hardware problem, and how can I definitively verify it one way or another, and get this sorted. I'm itching to get this thing in the air!
Glenn,
The 3DR assembly instructions are incorrect. I posted about this about a month ago and there has been another recent thread about this, but there has been no acknowledgment by the folks at 3D Robotics that this is an issue. I understand that mistakes happen, and that as a community based project, it is our responsibility to learn about these mistakes and provide feedback. With that said, I am greatly disappointed with the response of 3D Robotics, since this documentation should have been corrected already and new people should not be suffering through this.
For reference, the posts are:
http://diydrones.com/forum/topics/arducopter-3dr-build-documentatio...
http://diydrones.com/forum/topics/frame-assembly-possible-error-in-...
Good luck and let us know if these topics help to address your issues.
Pat
Everything is absolutely dead level when I plug it in. I am 100% aware of the requirement for this. Even running a level command while it is sitting flat on the bench and switching back to the flight data tab, the compass and roll still show that they are moving.
It sounds like it's in simple mode, but it's definitely just set to straight stabilize mode without simple enabled.
I've got it sitting on a flat bench here and connected to mavlink now, and the compass is constantly moving, and the roll is also moving quite a bit. I think this is where all my problems are coming from, but I don't know if it's indicative of a bad compass, APM or something else? I have attached a screenshot
arduopter yaw roll drift.jpg
Unfortunately I have been unable to successfully repeat that hand test. The thing that really gets me, is that the behaviour isn't always repeatable, and I'm not sure where the problem could be because of this.
Last night after the successful hand test, keeping all connections exactly the same, I powered it off, plugged the lipo in again on a flat surface, and then instead of trying to maintain a flat orientation it wanted to roll strongly to the right.
Hand testing it this morning, it seems like motors 3 and 4 are responding correctly, but motors 1 and 2 only increase or decrease in speed when the throttle is manually changed. The fact that the speed of motors 1 and 2 are changing with throttle input makes me believe that the connections from the APM through the PDB to the ESCs are fuctional, otherwise the motors wouldn't be able to have their speed controlled at all.
I think I may have made somewhat of a breakthrough, but I'm not sure how to verify it. During the hand test, if I rotate myself (yawing the quad) different sets of motors will start to respond when the quad is deviated from flat. So in the above scenario, where motors 3 & 4 were responding correctly before, rotating it will make motors 1 & 2 start to respond, or a combination of the 4 but it still never really wants to stay flat. Does this mean that I could have a faulty magnetometer?
OK this just gets weirder. I pulled the whole thing apart, checked every connection, recalibrated the ESCs and gave it another hand test.
At 25% throttle, the hand test fails. Motors 3 and 4 are doing all of the work when the quad is rolled or tilted, and 1& 2 do nothing (other than maintain a low rpm).
However at 50% throttle, all motors work properly. In the hand test it fights every pitch or roll change off centre.
This isn't how it's supposed to be right?
Any ideas why at low throttle a couple of motors don't seem to be responsive?
Yeah I have tried swapping the connections of 1&2 and 3&4, but that doesn't help.
Ok , so latest hand test, when rolling the quad to the left by hand, motor 2 increases in speed to compensate, and when tilting to the right, motor 1 increases in speed. This is correct behaviour yes?
The thing is, it appears motors 3 and 4 remain at constant rpm no matter how much the quad is tilted either way. What could the cause of this be?
Actually scrap that horizon comment, that's correct behaviour and shows that the APM is oriented properly, but does anyone have any ideas about what's going on here?
To me, the title of this thread seems to suggest that many, many, many arducopters are prone to flipping on take-off. I don't think that's fair/true. If fact I think that in at least 90% of the cases arducopter is not to blame, but some setup error or another (non-arducopter) hardware error.
In the hand test, does the copter stabilise ? I mean, if you try to tilt it by hand, does it resist and want to get upright again, or does it amplify the hand-induced tilt ? If it resists in all directions, then motors, props etc seem to be setup correctly.
In that case I would carefully examine transmitter-receiver. The fluctuating pitch ain't normal. Motors going full throttle by themselves ain't normal either.
Are channels reversed ? Did you calibrate radio correctly ? In CLI go to test->radio and examine the output of every channel. It should go from -4500 to 4500 on full stick movement, except for throttle, which should go from 0-800. Values of 4450 are fine too. Values of like 3000 are way to far off and you need to calibrate radio.
The values also shouldn't fluctuate more then about 10 if you don't touch the sticks.
What tx and rx do you use ?
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