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V-Bar 3.XX Useful Hints&Tips and Links





V-Bar Manual
Home of the Wiki
V-Stabi.de
V-Stabi Forum
The v-bar User Wiki








V-Bar Setup Guide Pt I
By Fergus
V-Bar Setup Guide Pt II
By Fergus
V-Bar Setup Guide Pt III
By Fergus







Further V4 information is available from the official Vstabi Team. Follow the links below

V-Stabi Version4 Trailer
Official V-Stabi Version4 Site.





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2 pages [ <<    <    ( 1 )     2     NEXT    >> ]3219 viewsPOST REPLY
Hobby Hut . Heli Wholesaler . JR-Spektrum

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Flybarless Rotor Head Systems > v-bar tutorial
 
 
fergus
Key Veteran
Location: Ireland

My Posts This: Topic  Forum
I am working on a v-bar software tutorial. The first draft covering the basic setup is posted in my gallery. It is a work in progress and is only in the early stages. Anyone with ideas or who wants to suggest omissions or corrections please post or PM. Many of you already flying v-bar will find the early release very basic. I hope to update it as I go and value your input.

Most info is out there on the forums already. I want to use this tutorial to gain a better understanding for myself and maybe it will be of use to others.

Thanks

Regards

Fergus
01-04-2009 12:39 AM
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tchavei
rrProfessor
Location: Portugal

My Posts This: Topic  Forum
Very nice.

A few hints:

1. you mention "adjust the endpoint of appropriate channel in your Tx as necessary to achieve 100%"... you should also mention the value 1600 because in the expert mode, in live screen, you work with absolute values, not %.

2. You should say why people should adjust the tail between 50 and 60 or so. There are some servos that will go powerless on the value of 64 on side A (and sometimes even lower) so the user should double check he has power at the extremes

3. You need to mention that people have to check if tail compensation is working the correct way. On a clockwise rotating head the tail wants to naturally go counter clockwise to the tail compensation has to be correcting clockwise. With the latest "I" theory that MrMel has posted, this might be avoidable since you don't rely on tail compensation anymore but until V4 comes out, I would always want to set it correctly.

4. You should explain better the flight trim part. you need to trim the heli in a hover, in a full climbout and in a full descent (or inverted climbout) so that you can adjust the swash at center, top and bottom. One should also look out for phasing issues. There are two techniques for that.

a) from a hover (tail in), give full collective and enough down elevator as if you where taking off in a drag race. If the heli shoots to the left, you need to adjust the phasing in the swash menu counter clockwise. If its to the right, you adjust clockwise.

b) from a hover (tail in), do a half forward flip. If the tail gets out of the axis (not exactily in line with you anymore) than phasing is off. if the tail is pointing to the far left, you need to rotate the swash layout counterclockwise, if its to the far right, you need to rotate it clockwise. Always start by one degree at each time to get it perfect.

5. You should mention that the sensor has to be perfectly square with the longitudinal axis of the heli although the cable can be pointing to the rear or to the front.

6. Don't forget to mention tail piruette optimization to get the vstabi to correct while piroetting.

7. It is important to set cyclic gain in the cyclic menu (bottom left) to 109 when you activate geometry correction. Someone screwed up and geometry only gets perfect when that value is 109. Not lower, not higher.

For now, I think thats all.

PSI,Bell and Hiller should be mentioned but I'm lazy right now. I'll post something tomorrow.

Tony


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"Perfection and patience usually walk side by side..."
01-04-2009 02:37 AM
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Mapleleafs
Veteran
Location: Ontario, Canada

My Posts This: Topic  Forum
wow crap, someone knows his stuff.....good job man.

TEAM ROTOR RC
Outrage Velocity 50, Outrage 550, Trex 450 Pro, Ely Q Vision 50
01-04-2009 02:59 AM
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tchavei
rrProfessor
Location: Portugal

My Posts This: Topic  Forum
Vbar would be much simpler if the key players (aka veterans) wouldn't behave like a freaking secret society holding the holy grail.

I must be public enemy #1 on the Vstabi forum with all the questions I have posed and with all the complains I did about the tail. I'm glad that someone started to write a clear manual about what needs to be done. I'm sure it will get more and more complex with time but as long as it is well written and understandable it will make things alot easier for newcomers.

Its a shame that with V4, most of it will be obsolete but then again, its better to know how things actually work than having everything hidden from the enduser.

Tony


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"Perfection and patience usually walk side by side..."
01-04-2009 03:20 AM
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THX1138
Elite Veteran
Location: Plainfield, IN

My Posts This: Topic  Forum
Very interesting...


Lou

Eigenharp enthusiast.
01-04-2009 05:17 AM
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fergus
Key Veteran
Location: Ireland

My Posts This: Topic  Forum
Thanks for the suggestions Guys. I have alot more info to add. I am concious of not overcomplicating things for beginners. That's why the initial setup did not include ever entering expert setup.

I think a second document on fine tuning with the expert setup tabs might be the best option.

Regards

Fergus
01-04-2009 09:06 AM
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Talron
Senior Heliman
Location: Winnipeg, Manitoba - Canada

My Posts This: Topic  Forum
You should consider adding this to the V-Bar Wiki. It is located here:
http://vstabi.de/user_wiki/index.php5?title=Main_Page

Ron
01-04-2009 02:53 PM
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MrMel
rrProfessor
Location: Lidingo, Sweden (GMT+1)

My Posts This: Topic  Forum
Quote 
Its a shame that with V4, most of it will be obsolete but then again, its better to know how things actually work than having everything hidden from the enduser.

V4 includes a totally new firmware, so it might be that some values arent even hidden in the future, rather "non-existant".
Well see.

My site: http://heli.dacsa.net
01-04-2009 04:13 PM
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tchavei
rrProfessor
Location: Portugal

My Posts This: Topic  Forum
If it works better, all power to them. The only thing I'm concerned is that since some parameters will be "non-existant" how will you be able to tweak the setup for your own taste? If independent Bell/hiller values dissapear, then the only way to adjust the speed between ail and ele will be through the radio. If they remove tail compensation but in your particular case, Theory "I" doesn't work that well, how will you be able to go around it? These are just some examples of what could go wrong.

Tony

PS - I haven't got the chance to test the bird with the increased tail rotor diameter. Hopefully next week though


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"Perfection and patience usually walk side by side..."
01-04-2009 06:06 PM
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fergus
Key Veteran
Location: Ireland

My Posts This: Topic  Forum
I will put up a post in the wiki forum which is the best resource for finding information as those involved in the design post there regularly. I have a link to it in my vbar gallery.

I have two further articles nearly completed. One is on bank switching and the other covers trim phasing and piro optimization. I will let you guys no when they are online. Please keep the suggestions coming. I am learning alot as I go here which was my intention. If I have anything wrong guys let me know

Regards

Fergus
01-04-2009 06:44 PM
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Talron
Senior Heliman
Location: Winnipeg, Manitoba - Canada

My Posts This: Topic  Forum
The link I provided is for the USER wiki. Anyone can add to it. Some useful info there.
01-04-2009 06:48 PM
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MrMel
rrProfessor
Location: Lidingo, Sweden (GMT+1)

My Posts This: Topic  Forum
tchavei, thing is that im not even so knowledged about the vbar to be able to come upp with stuff 'outside the box' which they are doing. I.e. You dont have those issues on a spartan , you set gain and stopping power, perhaps it will be the same for vbar, we have to see.
For sure is that modes are no longer, trimflight not needed, whatelse, interesting spring coming for sure

My site: http://heli.dacsa.net
01-04-2009 07:04 PM
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tchavei
rrProfessor
Location: Portugal

My Posts This: Topic  Forum
I can understand that however, in case of the tail algorithm, it puzzles me how they are going to simplify the fixed PID they use. The spartan works in 99.99% of the helis its mounted on because it doesn't just rely on a fixed PID like the 401. I obviously can't mention the details of the internatl workings but I can tell you that there is a reason that "adaptive" is part of the Ds760 name.

So unless Mikado has finally put its heart on really making a completely new algorithm for the tail, making an internal fixed PID might work for like 60% of the helis out there but certainly will pose problems for the other 40%.

Tony


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"Perfection and patience usually walk side by side..."
01-04-2009 07:27 PM
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Mapleleafs
Veteran
Location: Ontario, Canada

My Posts This: Topic  Forum
it would be nice if spartan rc came up with a 3 axis FBL unit....

TEAM ROTOR RC
Outrage Velocity 50, Outrage 550, Trex 450 Pro, Ely Q Vision 50
01-04-2009 09:52 PM
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tchavei
rrProfessor
Location: Portugal

My Posts This: Topic  Forum
Oh they will.

My personal opinion however is that Angelos is a perfectionist so it will take some time before they come out with something like that but it will be perfect.

Tony


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"Perfection and patience usually walk side by side..."
01-04-2009 10:13 PM
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tchavei
rrProfessor
Location: Portugal

My Posts This: Topic  Forum
Cyclic Menu:

Gyro deadband: Its an important parameter. Basically you define how much movement the gyro should ignore before taking corrective actions. too low and your system will draw more power as the servos will be constantly moving and any present vibration will be translated intro drift. this is specially noticable on the tail.

On the other hand, a too high deadband will make the heli "dance" in a hover because the system will only correct unwanted movement when it exceeds the gyro deadband threshold. Many users interpret this "dance" wrongly as having a loose tail but if the users looks very closely he will see the tail not only moving lateraly but also vertically. This is because its in the tail you see small oscilations of the rotorhead. Personally I've been happy with a deadband of 5. I tried 8 but that would make the heli dance in a hover. Recently, one of the Mikado owners refered that this parameter was to be set to 0 on electric birds. I have a vibe50 so I'm not going that low.

Rc deadband: This is similar to the gyro deadband but can't be interpreted as a stick band per se because its so sensitive that you won't notice a diference when moving the stick. Its main purpose is to eliminate very small signal fluctuations of the Tx's pots.

For example, when you use subtrim to match the tx to the live menu, you will rarely get a perfect 0... what you will see is probably a 1 or a 2 and even those values will be floating more or less. On a 14mz I can see the values changing every other second from 0 to 2 and back. If the RC deadband is set too low, the Vstabi will assume these fluctuations as rc inputs and react acordingly.

Cyclic gain: Like I said previously, it should be set to 109 to work acurately with the geometry correction however let me explain a little what it does. Many people are convinced that it just raises the level of response of the cyclic inputs (which is true) however what most don't know is that it also affects vbar corrections when the head moves without user input. The value of 109 will increase the vbar response in about 9%. This will translate into a more stable hover as the vbar will have more authority to correct oscilations.

paddle weight: Boy do we get this parameter wrong. In traditional flybar heads, the paddle weight controls stability and cyclic agility. In the vbar, paddle weight is only responsible for stability around center stick. You could define 200 and still have a lighting fast cyclic. This parameter has to be defined acording to the user preference of stability in a hover. Too much and the heli will feel unconnected as it will hover hands free without user input. Too low and you will be correcting the heli's position like on a 600N . I'm using 100 but I've seen people running 75 with good success (albeit more instable)

Paddle Steering intensity (PSI): This parameter is basically responsible for a low or high cyclic rate. Its coupled with the bell parameter and usually should always maintain a 2:1 relation to bell. The higher you go here, the more cyclic authority you will have. Personally I'm using between 50 and 55. Too low values will make the heli overshoot the defined target movement (like during a roll or flip). Too high and it will make the heli strike back during cyclic input. Its the balance between PSI and Bell that makes the miracle of vbar come alive.

Bell and Hiller: I won't go into technical details on this one as one could write a thesis about the interactions between both values. What the vbar user needs to know is that hiller has a slow but long lasting effect while bell has a fast but short lived action. Bell should be always twice the value of PSI and Hiller should be kept at 10-14 when running ultra mode to avoid building oscilations during flight.

Cyclic ring: Well, basically what the 12X and the 14mz has. It limits the servo travel in the upper and lower corners. The correct way to adjust the cyclic ring is to give full elevator and keep reducing the cyclic ring until it starts to affect the swashplate. Once you reach that point, back off 2-3 points and its set. YOu can test it on aileron too and then play with the values until you find a middle term.

I haven't studied gyro gains in the cyclic menu yet so I don't have a clue. The prefered value seems to be 30 but I've seen some users going up to 40.

Proportional, AOF to be followed.

Tony


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"Perfection and patience usually walk side by side..."
01-04-2009 10:54 PM
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fergus
Key Veteran
Location: Ireland

My Posts This: Topic  Forum
Two more documents posted.

Tony I will have to mention you in the Credits.

I also posted a link in my gallery script to the v-bar user wiki. That was what I was after in the first place

I don't know how I had missed it till now.

Regards

Fergus
01-04-2009 11:00 PM
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tchavei
rrProfessor
Location: Portugal

My Posts This: Topic  Forum
Only problem with the user wiki is that real flight examples and consequences of playing with the values are mostly omitted

Tony


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"Perfection and patience usually walk side by side..."
01-04-2009 11:02 PM
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MrMel
rrProfessor
Location: Lidingo, Sweden (GMT+1)

My Posts This: Topic  Forum
Quote 
So unless Mikado has finally put its heart on really making a completely new algorithm for the tail

Pretty sure VStabi has done just that.

My site: http://heli.dacsa.net
01-05-2009 06:30 AM
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geirgr
Heliman
Location: Norway

My Posts This: Topic  Forum
Change of mode

Why does vbar apply default values to AOF, Hiller and Proportional when changing between classic, extended and Ultra mode? Important to remember youre values if you have to swap to e.g. classic for some fine tuning. Is there a way to disable this?
01-27-2009 07:42 AM
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