AR.Drone GoPro mount camera

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szuu
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AR.Drone GoPro mount camera

Post by szuu » 26 Apr 2012, 18:29

Tizzy wrote:worried about the weight on the front pulling the drone forward and without the mod that's most certainly a recipe for quick disaster. With the macG at least I can tweak shift the control balance to favor reverse.
i doubt it makes any difference, the drone internal algorithms automatically maintain horizontal attitude when the control is neutral. So you definitely don't want to change the neutral position.
Of course adding the unbalanced load MAKES the difference, but a different kind, the front motors will simply work harder and there will be not as much spare power for certain kind of maneuvers, resulting in overall stability decrease.

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Re: AR.Drone GoPro mount camera

Post by Tizzy » 26 Apr 2012, 19:08

true, but only with autopilot enabled and at height that's just too dangerous imho. So when I fly outside I always switch it to absolute control (I think it's called these days?). But that also means it will have a tendency to tilt forward and dive... Changing the control balance just means I have something in reserve for reverse, but now I'm just re-versing.

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AR.Drone GoPro mount camera

Post by szuu » 26 Apr 2012, 20:45

Tizzy wrote:true, but only with autopilot enabled and at height that's just too dangerous imho.
If you mean disabling "auto hover in place", then yes, it will improve the stability, but for a different reason - the drone won't try performing violent "jumps" to stop immediately when you release the stick (was it called a "startled rabbit syndrome"? :P) and any rapid movement can be fatal when carrying the additional unbalanced load. Without the "autopilot" the general rule is even more true: "neutral control = drone stays horizontal" (when it's enabled, the rule changes to "neutral control = drone stays in place" (can tilt on its own to counteract the wind), unless it's ardrone 1.0 at high altitude, then the "autopilot" is disabled anyway)
Tizzy wrote:So when I fly outside I always switch it to absolute control (I think it's called these days?).
No, that is is a different thing, about compass and heading
Tizzy wrote:But that also means it will have a tendency to tilt forward and dive... Changing the control balance just means I have something in reserve for reverse, but now I'm just re-versing.
The tendency is true, but it is not something you can or have to offset by control settings. It just happens automatically, because what you control in drone is not the motor power or rotation speed - but directly the tilt angle. Attaching unbalanced payload changes the motor load balance, but not the drone attitude, it is always control zero = tilt zero, and shifting the control balance would make the drone go backwards by default, not quite a good idea.
You could, however, setup a different sensitivity for forward and backward tilt (if your controller allows that), this could protect you from applying too much forward tilt, while still allowing for full backward tilt.

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Re: AR.Drone GoPro mount camera

Post by Tizzy » 26 Apr 2012, 21:11

szuu wrote:
Tizzy wrote:But that also means it will have a tendency to tilt forward and dive... Changing the control balance just means I have something in reserve for reverse, but now I'm just re-versing.
The tendency is true, but it is not something you can or have to offset by control settings. It just happens automatically, because what you control in drone is not the motor power or rotation speed - but directly the tilt angle. Attaching unbalanced payload changes the motor load balance, but not the drone attitude, it is always control zero = tilt zero, and shifting the control balance would make the drone go backwards by default, not quite a good idea.
You could, however, setup a different sensitivity for forward and backward tilt (if your controller allows that), this could protect you from applying too much forward tilt, while still allowing for full backward tilt.
This last bit is indeed what I was trying to say using the self inflicted term 'control balance'.

We're eye to eye on the startled rabbit but I'm not clear on 'Attaching unbalanced payload changes the motor load balance, but not the drone attitude'. You mean when autopilot is on surely? Otherwise load in front of CG would tilt it forward and without the autopilot to correct it should fly forward, no?

Perhaps I should just fire up the wifi controls and see what happens with AP (autopilot) on inside. Should give some indication of stability. But that will be tomorrow then as in the flatlands it's now too dark to do much without banging a nostril somewhere. I'll post back after a short indoors wifi-flight.

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Re: AR.Drone GoPro mount camera

Post by szuu » 27 Apr 2012, 03:03

Tizzy wrote:I'm not clear on 'Attaching unbalanced payload changes the motor load balance, but not the drone attitude'. You mean when autopilot is on surely?
i think you put too much meaning to the whole "autopilot" and a seemingly unique ability to disable it by using the RC mod. in fact, wifi users disable it all the time, without even knowing someone calls it "autopilot", this is just the normal way to fly ardrone.

so what is "autopilot" and why it is so important in RC mods?

it is the ability to hold the position without drifting, when the pilot stops touching the controls.
normal ardrone apps sends the "hover" command whenever the pilot releases the virtual directional stick, which is very safe behavior for beginners - the drone stops immediately when the panicked pilot needs a while to think about the next move. but instead of releasing the control, we can also move it slowly to the neutral position, and keep holding it for as long as we need - the drone will then level the flight smoothly, without any twitches.

physical stick of the RC transmitter does not distinguish between "neutral position" and "neutral position but still touching", so there is an option to assign the additional switch to select between these 2 states, or, if you disable the "autopilot" permanently, it is like if you used freeflight while holding the directional stick all the time.
someone could even add an option in the wifi application to "disable the autopilot", like the RC mod does, but it is not very appealing, when every app "disables" it anyway every time you touch the screen.
Tizzy wrote:Perhaps I should just fire up the wifi controls and see what happens with AP (autopilot) on inside. Should give some indication of stability. But that will be tomorrow then as in the flatlands it's now too dark to do much without banging a nostril somewhere. I'll post back after a short indoors wifi-flight.
yes, definitely! you can try it on wifi with "autopilot" (not touching the screen) or without "autopilot" (when touching) and it won't change the way ardrone balances itself, just the amount of drift.

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Re: AR.Drone GoPro mount camera

Post by Tizzy » 02 May 2012, 18:56

Haven't been able to find the time to fly yet but hope to soon. Thanks for the analysis tho. Will call it 'autohover' from now on :-)

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Re: AR.Drone GoPro mount camera

Post by Tizzy » 10 May 2012, 17:47

Finally managed to find the time to assemble the drone around the new gopro hull, but it was basically unflyable due to lack of ummpf in the motors. It managed to hover at about 1foot off the floor and any maneuvering was quite unstable. Further investigation found two motors in need of replacement so will post back when I have more time to do another testflight.

Well impressed with the clearance tho still not enough to clear a hard landing, so no proper flying yet until I get my RC mod back (which got lost in the post on it's way to MacG for an update but which Mac was kind enough to replace free of cost, god bless him). Even then it's a high risk of scratching the lens so will be looking to even out the balance as much as possible and somebody pointed me to this oak who made a mouse of it http://dronescapes.com/dropage31.html" onclick="window.open(this.href);return false; Not a bad idea at all
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