First APM flight, problem with stabilization mode?

Hooray, got to the point where I've got APM set up and in a plane (Hawk Sky).  Now I need a bit of help diagnosing a flight problem.


I took off and got some altitude, and then flipped into stabilize mode. As you can see from the video, as soon as I did this, the plane started spiraling down and to the right.


I brought the plane back in and recalibrated gyros, but still couldn't get it to work.


Any advice appreciated!


Update:  As noted in the comments, I had the ailerons reversed.

Revised ground test and setup notes here.


Following that, here's what I did to reset and try again.

Views: 1413

Comment by Robert Krogh (hooks) on September 17, 2011 at 2:14am

Vibration could be your problem. You might need to install the AP on some anti vibration foam. Check if the motor / prop are balanced.

Comment by Peter Seddon on September 17, 2011 at 2:30am

Looks to me like a servo needs reversing. Have you checked the direction that the APM moves the control surfaces on the ground in Stab mode when you move the aircraft about? The APM should try and correct or bring the aircraft back to straight and level.



Comment by Peter Seddon on September 17, 2011 at 2:33am

I have looked at your second vid and looks to me as if when you bank the control surfaces move to increase the bank rather than opposing it. 



Comment by Jost Laznik on September 17, 2011 at 2:41am

Mark just switch the DIP switch 1 to reverse and your flight should go well. It looks gyros work well.

Comment by Andrew Tridgell on September 17, 2011 at 3:22am

The video shows that aileron reversal is definitely wrong. I'd suggest you set SWITCH_ENABLE to 0, which will disable the dip switches, then use the planner to set the reversals. Your video shows the left aileron giving more lift when you tilt the plane to the right, which is backwards. That means RC1_REV is incorrect. You probably want to set it to -1.

Check the elevator and rudder reversal as well. If you have some rudder mixing enabled, then tilting the plane right should engage some left rudder. Pitching up the noise should give some down elevator.


3D Robotics
Comment by Chris Anderson on September 17, 2011 at 4:27am

Mark, did you go through the flight setup process in the manual to check servo direction before you flew?


As we say (many times!), failure to check your servo direction before flight is the #1 cause of failure. (That's true for regular RC control, too)

Comment by Peter on September 17, 2011 at 7:51am

Mark, I think you should check whether your dip switch settings are correct.  This looks like an Elevon setup.  Please check DIP switch 4.


Comment by Cool Dude on September 18, 2011 at 12:35pm

Hi Mark,  I am also trying to build an APM using Dynam hawk. Although I do not have the answers to your questions, I do want to share with you some of my experience. As you can see in the pic below I have made a slot at the side of the fuselage and inserted a piece of thin wood. The APM is attached to this wood using double sided tape. The GPS is attached on the top using velcro. I used hot glue to attach the velcro. This setup  enables all the electronics to be inside the protective hatch.

  To enable easy power connect and disconnect, I have cut a part of the belly which is then fastened using velcro. This gives me access to the back of the fuselage where I install the small batteries for the APM. The batteries for the motor are at the front under the APM.

 I have still not flown mine using any of the auto modes. However it flies great in manual mode. BTW what config parameters did you use. I used the one for Bixler which Chris uploaded recently. I am hoping that it will work fine for this as both planes are very similar.

Comment by Mark Harrison on September 18, 2011 at 11:01pm

Thanks Guys!  Embarrassingly, it was my fault in getting the aileron visualization backwards.  I looked at it a dozen times, thinking "when the left aileron lowers, the plane will roll left."


I redid the setup, getting the ailerons correct... but I had incorrectly fixed the reversed rudder in the transmitter, so it was reversed when controlled by APM.  I didn't notice it while testing stabilized mode, since that doesn't use rudder.  My newest test includes fly-by-wire-a, which revealed that problem.

I'm having another unrelated problem... as soon as I resolve that, I think I'll be ready for another air test.

Thanks again!

Comment by Mark Harrison on September 18, 2011 at 11:04pm

Cool Dude, I like how your mod moves the APM into the fuse. Do you notice any weak spot where the battery bay or slots are cut?


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