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Old Jul 15, 2012, 09:48 AM
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rcbif's Avatar
United States, OH, Medina
Joined Jun 2005
1,021 Posts
Help!
Tricopter and HK KK2.0 board - Tail servo jitter

I talked to hallstudio, and have read a few other reports of tail servo jitter with this board and wanted to get a general consensus from tricopter pilots who have this board.

Basically, with p gain up the servo jitters side to side like crazy. With p gain down, and a bit more i gain to compensate, the jitter seems to vanish, but then you get an obnoxious nose returning to center (heading hold?) after a yaw input.
I've messed with just my yaw input for atleast 4 batteries now and over an hour, and there is no sweet spot.

This servo jitter is just not gonna work for aerial video/photo. It induces too much vibration into the frame, and looks downright painful to the servo.

On my HK 2.1 board, the servo never jittered. Unless we're missing something, this seems to be a pretty bad flaw in the programming.

So for now this board is useless to me .

I'm hoping kapteinkuk sees this and can chime in.
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Old Jul 15, 2012, 08:13 PM
Fly, crash, rebuild.
United States, NY, Shelter Island
Joined May 2011
877 Posts
Tricopter KK2 jittering yaw servo problem.

I second the motion.

Setup my kk2 in 15-20 on a new clean acro/aero profile. No expo or or dual rates. Clean. Pitch and roll are rock solid.
The yaw works great. Tight lock but a "crazy" flickering back and forth of the yaw servo sends harsh vibes through the frame.
Tweaking the yaw P gains down to 10-15, limits down to 10 and it gets a little better but the tri flies like a wet marshmallow.

I've ordered 2 different 25-26g servos 3-3.5kg 0.1-0.08 second at 4.8v to see if it matters.

I can see there is promise in this board but it is currently unflyable!
I will post video tomorrow.
KapteinKuK, we need your insight into this problem
H
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Old Jul 15, 2012, 08:16 PM
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United States, MD, Ellicott City
Joined Feb 2010
191 Posts
I had the same problem on my micro trial. I went into the mode settings and place the servo channel on high and it cleaned it up
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Old Jul 15, 2012, 09:08 PM
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rcbif's Avatar
United States, OH, Medina
Joined Jun 2005
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Quote:
Originally Posted by MIDNCOCO View Post
I had the same problem on my micro trial. I went into the mode settings and place the servo channel on high and it cleaned it up
micro tricopter? What servo?

When I put mine in high it makes a buzzing noise and does not respond.
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Old Jul 16, 2012, 12:34 AM
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Joined May 2012
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I have the same problem as rcbif. I tried with digital servo HK-D922MG, HK-D933MG and an analog servo. Keeping the same settings for PID, the wobbling is higher for servo 922 which has a greater speed. If I put on high servo channel 4 is even worse.
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Old Jul 16, 2012, 01:14 AM
Just noticed I can change this
Okisub's Avatar
Toowoomba QLD, Australia
Joined Nov 2005
99 Posts
Same problem here, using a D-MG16 from HK on the tail.

If I change the rate on the tail channel to high and it seemed to settle it a bit. Nowhere near as smooth as the old KK board and very noticeable on on-board video.
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Old Jul 16, 2012, 10:49 AM
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rcbif's Avatar
United States, OH, Medina
Joined Jun 2005
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Quote:
Originally Posted by iulian View Post
I have the same problem as rcbif. I tried with digital servo HK-D922MG, HK-D933MG and an analog servo. Keeping the same settings for PID, the wobbling is higher for servo 922 which has a greater speed. If I put on high servo channel 4 is even worse.
And did you change the yaw setting in the mixer editor from low to high for your digital servo as well?

No looking good so far.
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Old Jul 16, 2012, 10:50 AM
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rcbif's Avatar
United States, OH, Medina
Joined Jun 2005
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Quote:
Originally Posted by Okisub View Post
Same problem here, using a D-MG16 from HK on the tail.

If I change the rate on the tail channel to high and it seemed to settle it a bit. Nowhere near as smooth as the old KK board and very noticeable on on-board video.
http://www.hobbyking.com/hobbyking/s...idProduct=6608

did you know it's advised not to use your servo with gyros? I assume the kk board would basically count as a gyro too.
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Old Jul 16, 2012, 10:53 AM
Fly, crash, rebuild.
United States, NY, Shelter Island
Joined May 2011
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Quote:
Originally Posted by shelterock
I find it hard to believe the analog servo won't work. These analog servos are sold by the millions and deliver consistent. I have 2 different 25g digital servos coming. We'll see but several different people with totally different setups, experiencing the same new problem with properly functioning servos smell funny to me.

Rolf, any thoughts on this?
H

"I will add a configurable low pass filter for the servo outputs, to avoid excessive shaking and premature servo failure when using low-end servos. " from KapteinKUK himself
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Old Jul 16, 2012, 11:38 AM
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rcbif's Avatar
United States, OH, Medina
Joined Jun 2005
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Quote:
Originally Posted by shelterock View Post
Quote:
Originally Posted by shelterock
I find it hard to believe the analog servo won't work. These analog servos are sold by the millions and deliver consistent. I have 2 different 25g digital servos coming. We'll see but several different people with totally different setups, experiencing the same new problem with properly functioning servos smell funny to me.

Rolf, any thoughts on this?
H

"I will add a configurable low pass filter for the servo outputs, to avoid excessive shaking and premature servo failure when using low-end servos. " from KapteinKUK himself
Nice!

Now just the wait for the firmware update
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Old Jul 16, 2012, 10:02 PM
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United States, IN, Kokomo
Joined May 2008
613 Posts
I can't believe you guys.
You don't realize that analog servos can't be driven at a high refresh rate. It's all over these forums.
Gee, I wonder why my servo buzzes and smells like it's burning up.
HUH?
I guess what I'm getting to is that, you are blaming KK for YOUR problems.
The board is solid.
By starting this thread you make it sound like the new board has serious problems.
Far from it.
From what I read here it is user error.
Cheap servos and / or the wrong configuration for digital servos.
You can't compare your experience with the HK KK board with it's analog gyros with the new V2.
Analog servos work with the analog gyros.
Guess what, you have a new situation with digital gyros.
I would guess that digital servos would be REQUIRED with digital gyros, wouldn't you?
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Old Jul 16, 2012, 10:24 PM
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rcbif's Avatar
United States, OH, Medina
Joined Jun 2005
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Quote:
Originally Posted by Phalanx-0 View Post
I can't believe you guys.
You don't realize that analog servos can't be driven at a high refresh rate. It's all over these forums.
Gee, I wonder why my servo buzzes and smells like it's burning up.
HUH?
I guess what I'm getting to is that, you are blaming KK for YOUR problems.
The board is solid.
By starting this thread you make it sound like the new board has serious problems.
Far from it.
From what I read here it is user error.
Cheap servos and / or the wrong configuration for digital servos.
You can't compare your experience with the HK KK board with it's analog gyros with the new V2.
Analog servos work with the analog gyros.
Guess what, you have a new situation with digital gyros.
I would guess that digital servos would be REQUIRED with digital gyros, wouldn't you?
Step off your pedestal buddy. We dont need your high and mighty attitude here. I imagine you are the type that flames and tears into newbies too.......

first off.......

"Gee, I wonder why my servo buzzes and smells like it's burning up."

-nobody is trying to run their analog servo at the high rate or has complained their servo does not work at high rate. That's just stupid. It's the problem is that it dosent work at the low rate.

"By starting this thread you make it sound like the new board has serious problems."

- I'm trying to find out IF the board has an issue by gathering others experiences. Some people do not have your infinite knowledge and need to ask questions. I'm not blaming kk for anything. If anything I'm blaming myself for possibly missing something, so I started this thread.

-And your argument toward me would make sense ,however, there are some who still have servo wobble with digital servos. These users may not be using top of the line digital servos, but should we really need to buy a high end $50 micro servo for a $30 board?

- And last off, KK himself said he can and is able to do something so the board will work with cheaper servos. How about that? If none of us ever raised the issue, it would never get put in the firmware, and people everwhere would needlessly be buying expensive servos for their budget projects.



your "incredible hulk" avatar suits you just fine...............
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Old Jul 16, 2012, 10:24 PM
Just noticed I can change this
Okisub's Avatar
Toowoomba QLD, Australia
Joined Nov 2005
99 Posts
Quote:
Originally Posted by Phalanx-0 View Post
I can't believe you guys.
You don't realize that analog servos can't be driven at a high refresh rate. It's all over these forums.
Gee, I wonder why my servo buzzes and smells like it's burning up.
HUH?
I guess what I'm getting to is that, you are blaming KK for YOUR problems.
The board is solid.
By starting this thread you make it sound like the new board has serious problems.
Far from it.
From what I read here it is user error.
Cheap servos and / or the wrong configuration for digital servos.
You can't compare your experience with the HK KK board with it's analog gyros with the new V2.
Analog servos work with the analog gyros.
Guess what, you have a new situation with digital gyros.
I would guess that digital servos would be REQUIRED with digital gyros, wouldn't you?
You might want to have a better read of the thread. Most of the posts here are referring to digital servos being used.
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Old Jul 17, 2012, 03:38 AM
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Joined May 2012
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Dear rcbif,
just to let you know that I fully agree with your above post (#12). I wanted myself to answer to the "hulk" but my English is not good enough for that ;o). Only thing I want to add to your post: not only the avatar suits him fine, but the user name as well-military formation in Ancient Greek warfare.
Cheers and happy flying!
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Old Jul 17, 2012, 05:28 AM
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crezzee's Avatar
Worcester UK
Joined Nov 2004
774 Posts
Hulk you have done yourself no favours with your comments.

There is a problem with this board in tricopter mode - fact.

There is a solution for the problem - low pass filter code in firmware (Mr kk has acknowledged and is fixing)

This same problem occured with the origional kk board using tricopter firmware and again a low pass filter was added in V1.5 / 1.6 firmware to fix it, see here

"Tricopter v1.5

-Added a low pass filter on the output to remove the vibration induced servo jitter.

-Also doubled the arming/disarming time to make accidental arming/disarming less likely to happen."

Now off to the naughty step Mr Hulk
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