My ArduPilot Trials - ArduPilot - First Test Flights & A View That Kills

 

My ArduPilot Trials Day 2

I started off the day very excited to see how a new day of testing would go. I'd re-read portions of the manual, searched for ArduPilot tuning posts and contemplated the replies I got from my previous post.

The conditions were great and I was ready to toss that sucker up and get some satisfaction.
Instead, I learned a lesson. You see the picture above? That's what you get when you fly your plane using the wrong configuration on your radio. Notice how the tall grass beacons my plane to follow it's shadow... Well it did! Fortunately for me the grass was tall and I was quickly able to see the problem and cut power so no damage to speak of.

After I double-checked the electronics and hardware I reset the model in the radio to the appropriate configuration I got a GPS lock and tossed it up. I waited to engage the ArduPilot, which was in Stabilize mode until I trimmed out the model. Wow, what a great flight. The Stabilize mode checked out wonderfully. My fellow flyers were impressed with how well it did, especially when I used the stabilizer to bring it in for a landing. It was truly great. I lined it up on the approach I wanted, into a slight breeze and cut the gas and it glided in perfectly.

My ArduPilot Trials Day 3
Like yesterday I started of today very excited to try the next test. After flying yesterday, I took home the plane so I could change it's mode from Stabilize to Fly-By-Wire-A.

I was all set and ready to figure out what the heck "tell it where you want to go and it'll figure it out" was all about (that's a slight synopsis of the description of the FBW modes). I got my lock, put the wing on and gave it a toss.

Again, I learned a lesson. Not a new lesson, but one that should have been very fresh in my mind. You see the pictures below? That's what you get when you fly your plane using the wrong configuration on your radio. Notice how the tall grass beacons my plane to follow it's shadow... This time the grass was shorter and right next to a service road! Fortunately for me it was the grass, which was tall enough so again damage to speak of, just a bruised ego as I had watchers and needed a rubber band to hold on the GPS which had popped off.

So just what was that lesson? No it's not "dont fly your stryker" or even "double-check your model". It's Use Checklists to avoid these type of problems. I could have been sent back to ground zero with either of these crashes. I'm now building some easy grease pencil checklists that I'm going to attach to the plane and complete right on the model prior to flight. That should save me from myself and from having to remember to bring the list!

Todays second attempt went very well. Again once I trimmed out and got the model into the AP mode the FBW worked very well. It is different than the Co-Pilot for sure, but I use the rudder to produce a flat turn. The flatter the turn the better it's keeping itself stable. I did not get the chance to do the tests that are recommended for FBW, that will be next flight. For now I'm very happy with the ArduPilot. I again used the AP to land the plane, which was a little off from yesterdays great landing but I blame that more on me and how nervous I was after drilling the plane into the ground two days in a row. It did remain very stable during the approach and landing the line up was a little off so I had to walk a few yards to retrieve it instead of a few feet like the previous day. No big deal.

Next Test, FlyByWire-B, although I'm not sure what to expect in this mode with the motor? I guess it just keeps it constant? If anyone can explain that I'd appreciate it.

Wish me luck!

Notice how it's not quite square to the frame of the first picture? That creates visual interest!

In the second shot the shadow almost forces your eye to whats outside of the frame.

The third shot conveys movement. Notice how the grass in the background is in focus yet the foreground grass is blurred as the plane smashes into it...
Last but not least a nice shot after the model was corrected.

Views: 382

Comment by Mike on April 2, 2011 at 10:10am
:)
Comment by Ed Stewart on April 2, 2011 at 11:13am

Thanks for sharing, I'm pulling together parts for shot at this later this summer...

 

Ed


Admin
Comment by Thomas J Coyle III on April 2, 2011 at 11:24am

Brian,

What brand of RC transmitter are you using? I bet it is not a Spektrum RC transmitter because model lock will not allow you to use the incorrect model configuration with the receiver that the transmitter is trying to bind to.

Just a thought.

Regards,

TCIII


Moderator
Comment by Brian on April 2, 2011 at 11:33am

Thomas, 

That would be a feature on the newer DSM2 Spektrum transmitters... I have a lowly DX6 DSM transmitter.  It does some things you should know about, like when two models have reversed channels from each other, it carries over the setting to the new model, you need to reverse the channel to match the new plane.  I have an AirTronics RDS8000 and am waiting for a new rx.  I'll use that when I get it because it has the 3 position toggle, mine only two position...


Admin
Comment by Morli on April 2, 2011 at 11:50am
Looks great :). Good luck and happy flying
Comment by Ritchie on April 2, 2011 at 3:43pm
We've all been there (I have on many occasions :D getting too excited about adding something). Nice to see it up though.

Moderator
Comment by Brian on April 9, 2011 at 8:03am
Well I'm off to test some PID gain adjustments and also turned the XY sensor to match what the code had said it should be. Needed to reverse the roll and possibly the pitch movements, obviously that'll be tested first! Hopefully there's enough temperature differences for me to get a little testing done. I have to go do a school thing w/the kids later so no more testing after this today. I'll be at it again Sunday AM.

Wish me luck!

Moderator
Comment by Brian on April 9, 2011 at 11:06pm

Well, as I predicted I was able to test but not get back online to report. My flight to day went very well. Conditions were good with no wind, temp was good and plenty of difference for the thermopile sensors to read between ground and sky.

My first test was to confirm the proper operation of the counter roll/pitch movements as I had just previously changed the orientation of the XY sensor to meet what the ArduPilot configuration lists. So it's now in the default setting. I had remembered that the roll was reversed for sure so I only made adjustment to the REVERSE_ROLL setting. Ended up that the Pitch was reversed as well. Settings now show:

#define REVERSE_ROLL -1 // To reverse roll, PUT -1 to reverse it
#define REVERSE_PITCH -1 // To reverse pitch, PUT -1 to reverse it
#define REVERSE_RUDDER 1 // To reverse rudder for 4 channel control setups

*****I am curious, what does the rudder channel not say to put a -1 to reverse the channel?
Is this different? My guess is that it's not any different than the others, but if somone knows differently, pleas post a reply!
I had also adjusted the SERVO_ROLL_P setting, it now reads:

#define SERVO_ROLL_P .007

Which takes me to the test flight. Like I said the conditions were very good. I had no wind so it was easy to see what the plane was doing versus what the wind was doing to the plane.

Observed: The plane seems to climb once the AP is engaged. The plane files well in regular RC mode and it's level. I think I will need to adjust the "trim" for the sensor to get out of the climb.

Observed: When testing full stick deflection, to the right I get a very nice tight turn but to the left it's much wider. I remember a discussion that spoke of a similar problem so I'm going to go hunt that down to determine where to fix the issue. If anyone knows which blog that was please post a link. I also noticed that slight drop in elevation during the long slow left turn. The right turn was so quick that I did not notice the drop in elevation.

Overall I am very happy. I just need to get the left and right turns symmetric, adjust the pitch as needed and add the Rudder to the mix. Right now I am not using the Rudder channel on the ArduPilot. I look forward to having some nice controlled flat turns.

Hopefully I'll be headed out in the am to test again. So wish me luck!

 

http://www.diydrones.com/forum/topics/pid-nav-troubles?id=705844%3A...

 

Comment by Ed Stewart on April 10, 2011 at 1:22am

@ Brian [Observed: When testing full stick deflection, to the right I get a very nice tight turn but to the left it's much wider. I remember a discussion that spoke of a similar problem so I'm going to go hunt that down to determine where to fix the issue]

 

It could be torque induced if it's favoring turning opposite your propeller rotation.  I've had that issue on over powered gas models in the past...  You can verify it by testing while reducing your throttle.

Ed


Moderator
Comment by Brian on April 10, 2011 at 8:51am
@Ed Thanks for the reply. I didn't think of torque. I'll try it @ different power levels to see how it reacts. I found the link in my previous post (which I edited into the posting my last reply), but I thought there were a few on that topic. I didn't find any others if you do, I'd like to read as much as possible on the issue. Thanks for looking. Hopefully I'll get out there this morning to try again.

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