Another arducopter flips on takeoff thread.

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.

2011-12-18 09-55 2.log

You need to be a member of diydrones to add comments!

Join diydrones

Email me when people reply –

Replies

  • Abbas,

    I also experienced this problem. I was trying firmware 3.3 after upgrading from an earlier version, on a genuine Pixhawk, some time back. After much searching I found a discussion telling the inquirer to reload the software by first loading a version of plane firmware then going back to copter. I loaded the firmware for plane then since many months had passed and 3.4 was now available, I loaded that on to the Pixhawk. I took the quad outside and it had never flown that good before.

    To summarize, I switched to Plane firmware then loaded Copter back on, took it outside, and it took off and flew excellent. I still went through the tuning process but it was very close with out of the box settings. Good Luck with finding your issue.

    Also, Adrian offers some excellent advice.

  • Usually the problem is pretty simple Abbas. Have a read through the items above. Check out the reply directly above yours, and the others. If nothing stands out, start again  from scratch, remove props, disconnect motor wires, remove your controller. Don't rely upon one source for your info, There are mistakes one the web!

    TAKE YOUR TIME, make a check-list and try to understand what you are doing at each stage.

    A useful technique (but potentially dangerous - so you didn't hear it here) is to hold your drone, give it a little power, then gently twist it, pitch and tilt and ensure that it fights you, rather than aids you. Try with the props off first and study the motors.

    As I said above, set all of the settings to basic or simple, don't try to run before you can walk. Only make one change at a time and record what you did.

    BTW, You may also find that trying to take off too slowly can cause issues.

  • I also have the same problem. My copter flips when I raise the throttle. My motors and props all are as described in the Documentation. Can anybody help me out?

  • Hello, i had the same problem. After hours and hours solving this problem - reinstal firmware, calibrating, checking props and motor directions i found out my APM is on drone mounted reversely.... :)

  • Ok this is how I fixed my flip problem with Pixhalk simple reload the firmware calibrate ESC 

  • Personally I can't remember how I fixed mine, It was probably something stupid like a reversed motor. but I would suggest double checking prop rotation and correct prop. Also, check all connections and security of all parts and wires, especially the flight controller. These machines operate in hostile environments.

    Run through the set-up/calibration and check using the APM false horizon - remember that dipping forward causes the horizon to rise, not fall!

    Double check your transmitter calibration. Ensure that all trim is zeroed: do not trim the Tx

    Ensure that vibration is minimized, e.g. balance your props! I normally use sellotape. Cut a small piece and lay on the edge of the prop, stick it down when the correct position is found.

    Set the defaults to "beginner", fiddle later , give yourself lots of space ;)

    Best of luck

  • I also have a flipping copter ;)

    I have just changed FC from a KK5.5 to a  Arducopter 2.5 (AP2 latest download) - both in X mode, using 'simple' control - everything on the airframe WAS fine before.

    The effect is that it trys to flip port to starboard on take-off

    I have recalibrated and checked over and over - all appears fine.

    However, When I connect the motors as shown on http://code.google.com/p/arducopter/wiki/AC2_Props_2 the CLI motor test was wrong! I had to connect as though the board numbering was 2431, rather than 4321.

    This actually has the effect of numbering the rotors from the starboard bow 1 to 4 in a clockwise direction (way simpler - why complicate the hardware when it is so easy in code to nominate outputs?), and as I say, the CLI motor test works as per the diagram.

    Clearly one of these is wrong, but why is it not reported elsewhere (that I have found), although I would anticipate tipping more in a forward direction.

    I am going to attempt to fly it in the right(wrong) configuration tomorrow as per the diagram and ignore the CLI test, as this is driving me mad!
    Any comments in addition to those in the above thread would be most appreciated.

    Kind regards

    A

  • So I took the quad out for a go at the park yesterday.  I could get it to take off, but it required increasing amounts of roll input on the stick to get it to hover. Eventually it ended up taking off sideways at speed while at about 4m altitude, and I had to kill the throttle and put it down on the grass before it hit a building (snapping a leg in the process).

    I've attached the log from this (2012-01-02 05-18 7.log), and also the next log after unplugging/replugging the lipo where it would just try to flip over to the right (2012-01-02 05-18 8.log). I could just get it to take off with heavy left roll input, but couldn't hold it in the air. I'm not sure if i'm interpreting the logs correctly... I see there are corresponding changes in the roll and ch1 out, but how can I tell if the quad thought it was level or rolling while sitting on the ground or in the air?

    I guess the imu will be heading back to 3DR tomorrow, but I'm just worried they wont be able to reproduce this issue. ;(

    2012-01-02 05-18 7.log

    2012-01-02 05-18 8.log

  • This reply was deleted.
    • did you get he flip on take off problem fixed

  • Hey u4eake, so it appears that yes the sensors do zero and the drifting does go away when I arm the motors. When I disarm them though, the drifting will usually return, and rearming them will not zero the sensors or stop the drift. It seems to be intermittent whether the sensors will drift or not. Last night I had the quad connected via USB without lipo connected, and everything was rock solid for an hour, then I disconnected and reconnected, and it started to drift all over the place. 

    After a full teardown/resolder and a bunch of testing, I did manage to get the quad to hover for a few seconds today, but I do need to add some control input, and it's still very hard to get it to stay in one place. It wants to drift off to the right pretty consistently. After a few takeoffs and landings, I notice one side of the quad will want to flip over (towards the right) and just by looking at how blurred the text on the motors are as they are running, it looks like motor 1 (front right) isn't spinning as fast as the others.

    I have noticed that during the motors CLI test, holding the stick back to make the rear motors spin (2 & 4), they will go fast (from their sound), holding it left, motors 2 & 3 will go fast, but holding it up, both motors sound like they go slower, and same if I hold it right. It seems that any combination that invokes the use of motor 1 will run slowly, and I believe this is a symptom of the problems I am experiencing.

    So basically I thought the problem could be with either the motor, the ESC, or the signal path through the PDB for motor 1. I tried swapping the 3 larger connectors of ESC 1 and ESC 4, but kept the signal wire of ESC 1 plugged into the ESC1 port on the PDB. Then running the motors test, motor 4 now displays the behaviour that motor 1 previously displayed, so this tells me that motor 1 and 4 are both good.

    I then tried swapping the signal wires of ESCs 1 and 4 too, so that ESC4 is completely running motor 1, and ESC1 is running motor 4. During the motors test, any stick direction that spins motor 1 (running off ESC4 connected to the ESC1 signal on the PDB) will still make the pair spin slower than the others. This makes me believe both ESCs 1 & 4 are good too.

    So that just leaves the PDB if my logic is right? I resoldered every point for motor/esc 1 on it (the orange cable). It was after this point I did a hand test followed by a flight test, and could just get the hover, but it wasn't able to be maintained, and then after that I had the issues with it trying to flip over to the right on subsequent takeoffs.

    I'm just trying to rule out every potential place that this could be failing before I take the oilpan/mag off and send them in to 3dr since it will take weeks and I want to make absolutely sure the problem doesn't lie anywhere else, but as of now, I am stumped.

This reply was deleted.

Activity

Jose Araujo liked Jose Araujo's profile
Aug 29
spencer harvey liked spencer harvey's profile
Jul 9
More…