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Twitchy movements at slow speeds

Here are the videos testing the "twitch". Apologies for the iPhone quality video. I did discover that the ST16 sun shades makes a perfect tool to prop your smart phone on for videoing.

This first video is the H being tested in the slowest modes of Safe and Turtle. Legs up and legs down. She's very smooth, very little twitch.

Video #2 is the H flown in advance/pilot mode at slow settings (turtle). Again not twitchy at all.

Finally video #3 flying in fast modes, advance/pilot at rabbit setting. This is when it gets too twitchy and responsive as you will see. I'm making smooth, slow, small stick movements but it looks like I'm going full stick. Again, it's perfectly flyable, well maybe not for a newbie, but it needs to be much smoother than this.
David what you are calling twitchy in #3 is actually responsiveness. Hope they don't change mine. Go down to in between turtle and midway. Sorry but this is how I see it.
 
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I have to agree with those who say the H is twitchy. It is not fluid at all with small stick movements in Turtle mode which should be. It's difficult to keep a slow steady speed. I took some video with a tablet (good camera batteries missing....figures) comparing one of my quadcopters to the H. Sorry for the crappy video. It was getting late and the mosquitoes were eating me alive. Also the first H recording bombed so had to redo.

The quadcopter is Arducopter FC switching between Loiter and Position Hold. The slow lumbering moves is Loiter whereas the quicker ones are Pos Hold. Both are GPS mode and can be adjusted for "feel" (responsiveness to stick movement) but are set for slightly mushy response which makes for extremely smooth movement at slow speed. Without GPS mode, such as Stabilize, it will respond quicker but I didn't do that. However in all three modes there isn't any "jerking" when the command is intended to be for slow movement.

The H while smooth and stable during constant movement at moderate speed, does not transition smoothly from hover to roll/pitch command with even small stick movements. It should not tip hard when hitting 1% rate (I set the expo previously to have a dead zone and 25% expo to creep up on 1%). I had a discussion with Bo Lorentzen right after receiving the H. He said and appears to be correct there is a 2 degree minimum pitch/roll no matter how slow or little you move the stick. Once it hits that threshold, it's 2 degrees. It also looks to pitch/roll back about the same with very little opposite stick movement.

Maybe there are channel settings that will correct this I don't know (what I tried didn't work), but Yuneec really needs to look into this. Personally I think it is not a problem with the ST16 but a code issue. The point is, Turtle should be just that....all stick commands should result in very minute smooth pitch/roll movements without requiring perfect balancing of the stick position.

That's my only complaint on the flight characteristics of the H, and it should be a fairly easy fix.

Typhoon H

680 quadcopter





 
Great info Glider and your comments are spot on. It just needs a little smoothing out in higher speed modes. I'm sure an adjustment will be here soon enough.
 
This is a crazy week for me at work with travel so I haven't had a chance to play with the "over tilting" issue. Anyone else had a chance to call and discuss with Yuneec?
 
The main reason for twitchy Movement imho, is down to the harshness of the GPS braking, any hesitation with the stick results in the H trying to stop, which is effectivey what its trying to do all the time your flying in Angle mode, the problem is, the H GPS braking is harsher than the Q500`s, in turn, more noticeable.
 
The main reason for twitchy Movement imho, is down to the harshness of the GPS braking, any hesitation with the stick results in the H trying to stop, which is effectivey what its trying to do all the time your flying in Angle mode, the problem is, the H GPS braking is harsher than the Q500`s, in turn, more noticeable.

Can the GPS braking be adjusted or changed within the ST16?
 
Guys this is not a quad and it is lighter than your quad. It has two more motors, lighter,and you are starting to sound like parrots. You need to learn to fly this hex. Maybe you need to define your terms. I call it responsive you call it twitchy.
Every plane, heli I built took a little while to get use to. Some I would need to adjust curves and end points. As a fact I have some helis so twitchy your term I had to tone it down or not fly it.
So give this little hex some time, get use to it, complained to Yuneec , watch for firmware. In 6 months when the warranty is gone go into the channel systems and adjust your hearts out. Fly safe
 
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i have the same problem...Yuneec have told me to send the copter to service ....again :-(


it looks like i make movements on the right stick, but id didn't.
i just hold the position of stick for a slow flight
Eric I think I see what you are talking about. The gyro is trying to keep the H level after the input. Maybe there is a lag between input and the execution of it movement. Have you looked at the video to see if it showed up on it?
 
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I did testing this morning, the rocking(twitchy) motion goes away with GPS switched off. May be overactive braking or GPS positioning behavior, but it is there. I can get mt H to do a bunny hop for about 3 oscillations with slow smooth stick input then it smooths out. Any stick movement is exaggerated at slow speed with GPS on. It's in the code IMO.
 
Sounds like a conflict between gps and the gyro.
 
I did testing this morning, the rocking(twitchy) motion goes away with GPS switched off. May be overactive braking or GPS positioning behavior, but it is there. I can get mt H to do a bunny hop for about 3 oscillations with slow smooth stick input then it smooths out. Any stick movement is exaggerated at slow speed with GPS on. It's in the code IMO.
Agreed, but I don't think it is based on GPS positioning, just how the code is written for when it is in a GPS mode.

From what I can tell there is a minimum pitch/roll angle move with the slightest stick movement. Then when it's smoothed out and you're flying along, make another stick move and it "twitches" again that minimum angle. For whatever reason there isn't a nice smooth transition when a pitch/roll command is given to change the angle.

I haven't tried it with GPS off.

Hopefully Yuneec reads this forum and puts out a fix in the near future. It isn't a flight killer, but is a bit annoying. OTOH, constant twitching is a power waste.
 
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I have also observed this over control response to pitch and roll inputs when in angle/pilot mode. The response appears smooth in smart mode. Interesting.
Also, I observed similar characteristics with the early versions of the Blade 350QX quads. This issue appears to have been resolved in the Blade Chroma. FC code issues? In the old analog auto pilot days (passenger aircraft) we would have said that the gain was too high
 
I have also observed this over control response to pitch and roll inputs when in angle/pilot mode. The response appears smooth in smart mode. Interesting.
Also, I observed similar characteristics with the early versions of the Blade 350QX quads. This issue appears to have been resolved in the Blade Chroma. FC code issues? In the old analog auto pilot days (passenger aircraft) we would have said that the gain was too high


I have noticed the same thing....I hope this will be smoothed out in a future firmware release?
 
Actually, mine just started twitching after the firmware update. Never did it before. Now it can be hovering and it'll twitch. Maybe 2 to 3 times a battery pack and only at very low speeds or near-hover....
 
Unfortunately the firmware update did not correct our twitchy H's. However, now that we can switch GPS on and off on demand in flight, I find myself flying in non-GPS much more and it is silky smooth. As far as the comments above about the H not being twitchy, just "responsive" or that it is because it is a hex and especially that we need to learn how to fly (I've flown 90 size 3D helicopters for over 12 years and all quads for over 5 years), you are very wrong. While the twitch problem is not the worst thing in the world, it should be addressed at some time. For now when I need smooth flying, I just turn that GPS off and it's butter.
 
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Actually, mine just started twitching after the firmware update. Never did it before. Now it can be hovering and it'll twitch. Maybe 2 to 3 times a battery pack and only at very low speeds or near-hover....
Just for clarity sake, the "twitchy" that was originally called out was a very sudden bolt of the H whenever the right stick was moved. This 'sudden' movement smoothed out as the stick direction was increased. It was akin to the green light on the dragstrip Christmas tree and the dragster would bolt off the line and then the car and engine would catch up to the momemtum and the ride would 'smooth out.
If your H is 'twitching' while in a hover mode I am more inclined to believe it is atmospheric in nature and not software/hardware related.
 
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Thanks for the clarification, I didn't want to start a new thread. Regarding my issue, timing sure is suspect. Different locations, different days, UAV forecast says weather conditions are good... Didn't do this prior to the update either... I'm inclined to believe its the update...


Just for clarity sake, the "twitchy" that was originally called out was a very sudden bolt of the H whenever the right stick was moved. This 'sudden' movement smoothed out as the stick direction was increased. It was akin to the green light on the dragstrip Christmas tree and the dragster would bolt off the line and then the car and engine would catch up to the momemtum and the ride would 'smooth out.
If your H is 'twitching' while in a hover mode I am more inclined to believe it is atmospheric in nature and not software/hardware related.
 
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Glad I found this. Mine has done this since I got it back in May to the point I haven't flown it but 3 times since.
Pisses me off that my old Q500 flew better.
 
Glad I found this. Mine has done this since I got it back in May to the point I haven't flown it but 3 times since.
Pisses me off that my old Q500 flew better.

My didn't start until the 4th or 5th flight, or at least I didn't notice any twitching. Wish we had a fix for this.
 

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