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Old May 01, 2010, 05:43 AM
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Hi Daniel, roll direction is correct but pitch is reversed, can I change this? The elevons' movements are very "notchy", not sure how this will perform in flight, changing the gain altered the amount of deflection which is cool but the movement was very jerky until the ahi was level both ways, it sort of pulses. Is this ok or are there other settings to smooth it out?

Thanks

Mark
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Old May 01, 2010, 06:02 AM
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mark,

I'll look into those. Can you confirm that the aileron servos are acting in the correct manner? And that the pitch servo (elevator) isn't?

Also, are the servo movements smooth if stabilization is not activated? Likewise, how are the servo movements with no IMU attached to the OSD? Was the autopilot on when you noticed the "notchiness"?

I just tested my set without IMU installed and didn't really notice any unusual servo movements. This is without the stabilizer enabled though. The stabilizer will add input to the control surfaces which might appear as notchiness.

Daniel
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Old May 01, 2010, 06:08 AM
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Ailerons and pitch ok from transmitter, ailerons ok from stablization, pitch reversed from stabilization. Lift nose of plane up, elevons go up.

Mark
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Old May 01, 2010, 06:24 AM
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mark,

Okay, 62BETA6 is up and the pitch should be correct now. Can you describe the "notchiness"?

Daniel
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Old May 01, 2010, 06:37 AM
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You work fast, if I roll the plane to say 30 degrees, the ailerons will go to about 30 degrees then pulse to 20 degrees then back to 30 degrees at about half second intervals, maybe faster. I originally thought it was glitching but it looks too controlled. Looks like when you have too much derivitave in a PID loop.

Thanks

Mark
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Old May 01, 2010, 06:39 AM
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Okay, so you're saying that this servo movement issue is related to the stabilizer then? Ie. if the autostabilize gain is set to 0.0, there is no issue?

Do you see the servo movement related to the artificial horizon? The problem could be coming from the IMU itself.

Daniel
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Old May 01, 2010, 06:50 AM
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Definately autostabilize, no pulsing with zero gain. With the AHI on an angle but not moving servos pulse, moving the plane continuously the servos pulse, maybe IMU signal but with ahi stable it still pulses. Will video after flight in the morning if it creates a problem, 11:50pm now.

Thanks

Mark
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Old May 01, 2010, 07:05 AM
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mark,

Okay, I think I may have found the problem. 62BETA7 addresses this, hopefully.

About flight testing, I would certainly want to use BETA7 and start with small gain values. What kind of values are you using to get visible servo movements? You really want smaller servo movements than large ones.

*Edit: I've promoted BETA7 to release 6.2 so just download the DOSD62 and use that.

Daniel
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Old May 01, 2010, 07:14 PM
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Ive managed to dump my logs via serial terminal & convert them to a KML file, however the GPS coordinates are incorrect.
From the dump i get

2.048045,52.659485,370.0

My true coordinates are

-2.048045,52.659485,370.0

The dump is omitting the '-' from the start of the GPS coordinates, is this a bug Daniel?

Thanks.
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Old May 01, 2010, 07:33 PM
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Hi Daniel, Stabilization works sweet My IMU must be pointing up slightly as it kept losing hight but wing leveling was awesome, had gain a bit high but I have it on a switch to turn it right down or up, no proportional worked out yet. I have packed up the back of the IMU a bit and am going to fly again, video is processing on youtube. It's a bit long and I flew behind the patch antenae a bit but you can see it stabilize when it oscillates.
DOSD+ 6.2 firmware test IMU Stabilization (10 min 57 sec)


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Old May 01, 2010, 09:37 PM
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This time I have turned gain down to 16550 and enabled it with channel 5 after take off, channel 6 is control channel on DX7 3 way switch. Landed with stabilizing on. Would be good to have a menu to zero level flight while flying if that is possible? With no inputs the plane flew arond in big circles, need to adjust level of IMU.
dosd+ firmware 6.2 gain 16550 (7 min 7 sec)


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Old May 02, 2010, 02:24 AM
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mark,

In your second video, I can see that the artificial horizon was not level when you took off. That's probably causing the plane to fly around in circles.

Beyond that, it looks like sustained/coordinated turns is still giving the IMU some problems.

Btw, you do realize that these are the very first videos of an IMU stabilized DOSD+ flight. History!

Daniel
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Old May 02, 2010, 02:35 AM
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It's pretty cool aye Is it still critical to start the system up with the plane level? I don't really do that because I tried started it up with the plane on a lean until the orange light came on and it still ended up level. Did you see after I landed the ahi leveled out, it may be vibration still upsetting it in flight? I would like to try autopilot next, if I am out 1km it should fly back reasonably well I think, when I turn on autopilot what setting adjusts its sensitivity?

Thanks

Mark
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Old May 02, 2010, 03:19 AM
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mark,

While the plane does not have to be level, it does need to be perfectly still, no movement whatsoever, especially in the roll or pitch, until the light turns orange. The level is now dependent on how you mount your IMU. You may want to adjust that until it gives a level horizon line when perfectly level.

I assume you performed all the calibration as described in the write-up for 1.6e. That part is necessary too and will determine a large part of how well the IMU performs.

For the autopilot, just go with the default for now. You can increase ROTSTEPGAIN and ROCSTEPGAIN to make it more aggressive in the turns and climbs respectively.

Daniel
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Old May 02, 2010, 03:49 AM
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badlands,

Thanks for spotting that. Oversight on my part - I forgot all about that. It's fixed now in firmware version 6.3. Note that the error was in the logging process, not just the dumping one so unfortunately the existing logs cannot be used. Future logs will be good though, hopefully.

Daniel
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