Jump to content

Joystick Dead Zone and the Gazelle (MS FFB 2 and Logitech G940)


Drakoz

Recommended Posts

I have flown DCS (and other flight sims) with a Microsoft FFB 2 joystick for years. But difficulties flying the Gazelle due to its stability systems finally brought to the fore front an issue with the FFB2 joystick that makes it less than ideal for helicopters - or at least specifically the Gazelle. The issue is the FFB2 has a dead zone at its center position. The Logitech G940 and its hysteresis "feature" (commonly referred to as the "reversal bug") make it even worse.

 

The issue I am referring to exists with all joysticks with a built in dead zone, or to anyone that sets a dead zone using the joystick axis config. But it affects the Gazelle particularly. Many people have complained about the Gazelle being difficult to fly, or handling unnaturally. Having trouble holding it in a turn for example as it seems the Gazelle wants to turn in too hard, or not enough, and having to constantly adjust the joystick back and forth to keep it flying a level turn. Some of this is the Gazelle and the devs have done a lot of work to improve it but some of it is also the Gazelle doing what it is supposed to do, and the result being messed up by a joystick dead zone. To me, it was a little frustrating, but not difficult to overcome. I just had to be active on the controls. I did a video two summers ago to make this point showing an inset view of how I handled the controls and was able to keep the Gazelle stable (see below). But recently with all the Gazelle improvements related to this issue, I realized that the issue people are seeing may be just as much a matter of the joystick dead zone.

 

 

I realized the problem after some testing with recent updates when I noticed that as long as I had the FFB2 stick off the center spot, the Gazelle was easy to fly. But as soon as I had to pass through the FFB2 center point (the dead zone), I would get a jump in movement or an overreaction in the control. The dead zone causes a moment of hesitation where you get no input control to the helicopter. You tend to move quicker to overcome the dead zone and when you come out the other side, the input you issue is too much. This results in overcompensation and oscillation.

 

In a real helicopter, there may be a small amount of slop in the stick which creates an input dead zone, but that slop occurs exactly where you stop and reverse the stick. Not at a specific and unmoving center position like on the FFB2 where that dead zone has nothing to do with mechanical slop. It is wrong to use a dead zone period on a FFB stick as it defeats one of the benefits of using FFB. Microsoft really screwed up here by failing to understand the most fundamental benefit of their product! But people will have similar issues with non-FFB sticks as well. In fact, even if there is no dead zone on a non-FFB stick, the center detent position of the stick can cause similar issues. That is why FFB sticks are so popular for helicopter sim pilots.

 

On the Logitech G940, the issue is worse due to its hysteresis feature. It is called the reversal bug because every time you reverse the direction of any G940 axis (stick, throttle, or rotators/trim knobs,) it waits a moment (like a dead zone) before issuing input to DCS. At first thought, you might think that sounds like the slop I just mentioned in a real helicopter. Well, no. Once you have cleared the "virtual" dead zone or slop, it issues a new coordinate that is as if there was no dead zone at all. Meaning, when you reverse the G940 axis, it always jumps approx 1% of the axis travel after a moment of hesitation. At least with a dead zone, when you get to the other side of the dead zone, the new coordinate issued by the FFB2 is only a single step away from the previous side of the dead zone. Here is a Youtube video that shows what I'm talking about.

 

 

There is no way to solve this for the FFB2 short of adding a generic DirectX game controller board like a Bodnar or Teensy board acting as a new USB joystick, issuing the X/Y axis data to the sim while still preserving the original circuit board to handle the FFB. Several people have done this - there are forum topics on how to do it on the ED forums and elsewhere. The MS FFB2 has adjustable dead zone using the FFB2 software, but that software doesn't run under Windows Vista and beyond. I have loaded the software under Windows XP and tried to see if I could reduce the dead zone and have that reduction be permanent, but the FFB2 stick is by default already at the most reduced dead zone available. So even if the software worked under Win7/8/10, it would not help. Sadly, I have shelved my FFB2 stick because of this.

 

The solution for the G940 is to install the latest firmware (v1.42) that significantly reduces the hysteresis for the Joystick axis. For firmware v1.41 and earlier, the hysteresis is about 1% or 1.5% of travel. For v1.42, it is now 0.3% and barely perceptible. Unfortunately, the v1.42 firmware is not available from Logitech's support website. The v1.41 firmware is the last official version. The v1.42 was only semi-officially released on the Logitech forums and then abandoned. Logitech revamped their forums and the original topic discussing the release of v1.42 and the link to the download are gone. But I found them on archive.org.

 

https://web.archive.org/web/20120119090658/http:/forums.logitech.com/t5/PC-Gaming/G940-firmware-1-42-is-now-available/td-p/542496

 

And in the first post of that topic, you'll see you can download the v1.42 firmware from Logitech at this link:

 

http://www.logitech.com/pub/techsupport/joystick/G940_Update_FW0142.zip

 

Sadly, v1.42 does not fix the reversal bug for the throttle or the other analog axis. Meaning, using the G940 throttle for a helicopter collective is not a good idea. I now fly with the G940 joystick and Warthog Throttle. The G940 FFB is not as good as the MS FFB2, but the dead zone on the FFB disqualifies it for helicopter duties - at least for the Gazelle. It isn't all bad - the G940 is a very nice HOTAS. It feels nice in the hand and has a good array of buttons.

 

Finally, some of you may say, but I like having a dead zone on my joystick because I can let go of the stick and the aircraft stays where I put it. Again, for A FFB stick, this is wrong thinking. If you want a dead zone on a FFB stick, it should be at the current position of the stick (as held by the FFB motors), not at the center of axis travel. The G940 sort of creates this with its hysteresis, but when the stick reaches the end of its slop, it issues a 1% jump in axis position, which is even worse than the dead zone issue. The v1.42 firmware solves this.

 

As for dead zone on a non-FFB stick, having a dead zone is a personal preference thing. Since you are already dealing with a stick that doesn't work like the real thing (because it self centers - and that's not how helicopter sticks work), the center detent is the bigger problem, and adding a dead zone might actually be an improvement to compensate for the unrealistic centering.


Edited by Drakoz
Link to comment
Share on other sites

Exactly! This is what needs to be understood especially with the Gazelle s centric and sensitive cyclic. I got rid of the center detent a long time ago and the Gazelle became a lot easier to fly. Well all the helicopters became a lot easier to fly.

 

 

I don't use the trim function as my cyclic stays put where I let go of it sort of equivalent to FFB but using RC car dampers so it has a kinda hydraulic feel about it.

 

Still a WIP.

Control is an illusion which usually shatters at the least expected moment.

Gazelle Mini-gun version is endorphins with rotors. See above.

 

Currently rolling with a Asus Z390 Prime, 9600K, 32GB RAM, SSD, 2080Ti and Windows 10Pro, Rift CV1. bu0836x and Scratch Built Pedals, Collective and Cyclic.

Link to comment
Share on other sites

Drakoz, you deserve all recognition for this post.

 

Perfect description, extensive and detailed post and fantastic findings. My squad mates with the G940 will appreciate so much your inputs.

 

Thanks a lot mate.

" You must think in russian.."

[sIGPIC][/sIGPIC]

 

Windows 7 Home Premium-Intel 2500K OC 4.6-SSD Samsung EVO 860- MSI GTX 1080 - 16G RAM - 1920x1080 27´

 

Hotas Rhino X-55-MFG Crosswind Rudder Pedals -Track IR 4

Link to comment
Share on other sites

Thanks guys. Much of this has been understood for years and discussed in other forums (about the MS FFB2 dead zone and the G940 issues), but seeing how it affects the Gazelle especially was the big reason I summarized it here in the Gazelle forum as opposed to positing in the Input and Output forum.

 

I used to think the G940 was just a really bad FFB design, and with poorly designed gimbals - a week point for most FFB sticks. It is still inferior to the MS FFB2 gimbal and FFB design, but with the v1.42 firmware, now I see most the problem was the reversal bug. Again, with the reversal bug still affecting the G940 throttle and rudder pedals, these components are not appropriate for helicopter use. Only the G940 joystick with v1.42 firmware. The G940 still isn't perfect - it's gimbal and motor drive power are still lacking relative to the MS FFB2, but seeing just how bad the MS FFB2 dead zone was affecting my flying, the G940 is now a welcome relief.

 

Alternatively, FragBurn's idea of an unsprung stick without center detents, but with friction hold is an excellent solution as well - something I have considered trying over the years.

Link to comment
Share on other sites

interresting thread, I'm a pround owner of MS FFB2 for years.

love it with MI8 & HUEY (and i ll never give it away for helo against a warthog or virpil).

also I have some very good feeling with XP11 bell 407 and XP11 A350 ( very sensitive helo also ) with simFFB.exe.

 

but I've never had such a (bad) feeling of a (?coded?) hudge deadzone like with the gazelle.

no matter FFB option is activ or not in the misc option

no matter I have a linear curve or not

no matter I disenguage SAS autopilot stabiliser

 

I still have those feeling of a hardcoded deadzone, i have not this feeling with all oversensitiv helo like above. all very accurate in close center zone.

 

the Bell 407 is more sensitiv as the gazelle , also with the M2000C refueling I can give some little accurate input around center with no problem or such a feeling.

 

so definitely it's not a MS FFB2 limitation, but a problem in gazelle implementation. sorry but, for me, it just need some more work.


Edited by snowsniper
 

 i7-10700KF CPU  3.80GHz - 32 GO Ram - - nVidia RTX 2070 -  SSD Samsung EVO with LG  TV screen 40"  in 3840x2150 -  cockpit scale 1:1

- MS FFB2 Joystick  - COUGAR F16 throttle  - Saitek Pro Flight Rudder Pedals

 

Link to comment
Share on other sites

Okay an easy way to check is to go into the options and go to axis tune for the pitch and carefully and slowly (several seconds for any direction of travel*) move the cyclic forward and back the indicator should smoothly track the along the line with movement of the cyclic. You can check roll in the same way.

 

There should be a smooth transition across the center (well all of the travel) as the indicator follows the line whilst you move the cyclic. Watch the indicator to make sure that it's transition is smooth and it doesn't hesitate or appear to jump especially around the center of travel.

 

This is especially important if your controller uses potentiometers as the sensing element as after some use they become noisy or intermittent which will also show up as the indicator appearing to hesitate and jump as you move the cyclic.

 

As an indication I am currently using the gimbal and control PCB out of a Logitech 3D Pro and the gimbal needs to be replaced every so often, usually a couple of hundred hours because the potentiometers become too noisy and make flying harder then it should be. The first indicator is the the Gazelle gets a little erratic especially around center of cyclic travel and tends to do a slight nose up or down (or roll) action seemingly randomly. This of course gets progressively worse as you clock up more hours.

 

Hall effect devices either work or tend to diminish the output range or not work at all that's not to say they wont have the same effect I have just not seen it.

 

*Moving the cyclic fast may cause any defects to be masked.


Edited by FragBum
typo

Control is an illusion which usually shatters at the least expected moment.

Gazelle Mini-gun version is endorphins with rotors. See above.

 

Currently rolling with a Asus Z390 Prime, 9600K, 32GB RAM, SSD, 2080Ti and Windows 10Pro, Rift CV1. bu0836x and Scratch Built Pedals, Collective and Cyclic.

Link to comment
Share on other sites

ok,

no problem in center zone or eratic mouvement in conf, calibration, or DCS setting curves.

 

here is what i feel :

 

people complained gazelle was way too sensitiv at the early begenning.

so maybe a curvature must have been hardcoded in the gazelle to make it more "friendly" and easier.

 

so, when i put some more curvature in my DCS settings it amplifies the hardcoded curvature resulting that i have something like a huge flat zone

 

I did a test with Negative curvature (-10) and a saturation of 75%, and it seems that "huge dead zone" has completely disapears and a quite better feeling.

 

So for the Gazelle do not apply curvature or just a bit of negative curvature on X Y.

 

 i7-10700KF CPU  3.80GHz - 32 GO Ram - - nVidia RTX 2070 -  SSD Samsung EVO with LG  TV screen 40"  in 3840x2150 -  cockpit scale 1:1

- MS FFB2 Joystick  - COUGAR F16 throttle  - Saitek Pro Flight Rudder Pedals

 

Link to comment
Share on other sites

You may not have any dead zones programmed, however see the test video it shows clearly in my case there is a change in transfer curve verses movement around the center of travel and yes the physical movement of the stick was fairly linear. It doesn't seem to matter what model I test it in I get the same result, however this will impact the most on the Gazelle for various reasons.

 

Test video here.

 

The output from the joystick controller a Logitech 3D pro in this case (highly modified!) has a feature that tends to bring the output to center when the stick is physically close to center. keep in mind my stick has no mechanical centring or springs it moves freely. It has the same effect on roll as well. I suspect this action is part of centring the output so the when the stick is put back into what would be it's normal mechanical center in normal use the output would be "centered".

 

I tend to agree that applying saturation tends to mask the effect but I don't consider that as a solution to the problem. I'm working on my own cyclic with HALL effect sensors and a 3rd party USB interface.

 

DISCLAIMER I m not a pilot.

 

As for cyclic sensitivity I think from my limited experience the cyclic feels about right for a light helicopter, certainly with an extension on the joystick. I used to run saturation down to 28 for the Gazelle until I got some stick time wow talk about pilot induced oscillation the first time I tried hovering. :D

Control is an illusion which usually shatters at the least expected moment.

Gazelle Mini-gun version is endorphins with rotors. See above.

 

Currently rolling with a Asus Z390 Prime, 9600K, 32GB RAM, SSD, 2080Ti and Windows 10Pro, Rift CV1. bu0836x and Scratch Built Pedals, Collective and Cyclic.

Link to comment
Share on other sites

  • 2 weeks later...

Hi Gents,

 

Just to let you know, there's no controls curvature or else coded in the gazelle.

 

so maybe a curvature must have been hardcoded in the gazelle to make it more "friendly" and easier.

Link to comment
Share on other sites

  • 6 months later...

OK thanks for reply Pat.

 

For MSFFB2 owner :

here my best settings in 2.5:

 

game option set FFB curve to 1. not 0 or 100 or you 'll have a huge dead zone.

 

Axes X Y :

FFB setting invert / 30 % on forces 30 % on shake

 

X curves : -5 curvature + saturation Y 70%

Y curves : -5 curvature + saturation Y 70 %

 

feel more accurate for me with this joystick.

 

don't forget to set autopilot OFF and you go for some great fun and easy well controlled aerobatics.:joystick:

 

 i7-10700KF CPU  3.80GHz - 32 GO Ram - - nVidia RTX 2070 -  SSD Samsung EVO with LG  TV screen 40"  in 3840x2150 -  cockpit scale 1:1

- MS FFB2 Joystick  - COUGAR F16 throttle  - Saitek Pro Flight Rudder Pedals

 

Link to comment
Share on other sites

T-16000M here

 

no user made deadzone, very precise stick ( piloting a cruising huey means moving the stick inside a 3mm diameter circle )

 

 

but i have noticed a "huge" ( for me ) deadzone with the Gazelle in pitch down ( Moving the stick over 0.5cm forward has no effect )

Link to comment
Share on other sites

Sorry no experience with T-16000M, However following on from my previous post I have now integrated a Leo Bodnar BU0836X controller as my "cyclic" interface and can assure you there is no dead spot for cyclic input.

 

Do check and ensure that in Options->Misc that the Force Feedback option is NOT selected and Options->Special->342 that the FFB settings for roll and Pitch are set to Zero for both Roll and Pitch when using a non FFB joystick, this is important and can affect the cyclic input for the Gazelle.

 

Also keep in mind the cyclic input for the Gazelle is slightly different to that of Huey/Mi-8 in that it is totally centric in operation, no offset for change of CoG that is there seems to be no offset required from "centre" to balance the Gazelle like you would for the Huey or Mi-8 to bring the aircraft to balance. Which is why any built in dead spot coupled with a mechanical center detent is bad news for the Gazelle.

 

 

More here for Gazelle cyclic input.

 

 

From what I understand the MS FFB has a dead spot programmed into the controller and depending on the firmware the G940 may or may not have such a dead spot programmed in to the controller itself refer to the OP in this thread for more info.

Control is an illusion which usually shatters at the least expected moment.

Gazelle Mini-gun version is endorphins with rotors. See above.

 

Currently rolling with a Asus Z390 Prime, 9600K, 32GB RAM, SSD, 2080Ti and Windows 10Pro, Rift CV1. bu0836x and Scratch Built Pedals, Collective and Cyclic.

Link to comment
Share on other sites

Thx snowsniper for help...but no match for me.

I try all your setting, but deadzone survive...

I'm very frustrated!!!

 

 

well, maybe hopefully i wasn't very clear

when i mean FFB set to 1 it is in main menu option/special/SA342 menu both for pitch and roll

 

also it works nicely for my FFB2 don't know for G 940

 

bonne chance Santaklaus.

screenshot in PJ

Screen_181021_214036_1.thumb.jpg.3dbc29fa48b40de22307f3a47c0e7e32.jpg

Screen_181021_214045_1.thumb.jpg.00f8a7578a87cde1f76f8c5d728e3687.jpg

Screen_181021_214011_1.thumb.jpg.fc2f85d1f9e62c3c906c82d873127a84.jpg


Edited by snowsniper
 

 i7-10700KF CPU  3.80GHz - 32 GO Ram - - nVidia RTX 2070 -  SSD Samsung EVO with LG  TV screen 40"  in 3840x2150 -  cockpit scale 1:1

- MS FFB2 Joystick  - COUGAR F16 throttle  - Saitek Pro Flight Rudder Pedals

 

Link to comment
Share on other sites

hi,

 

My deadzone is probably caused by the FFB curved in option menu. Indeed, when i increased it, my deadzone increased too. For 0,the deadzone about the size of the red diamond (controls display), too big for a smooth control !!!!

can we remove this rotten and useless ffb curve option PLEASE !

Link to comment
Share on other sites

What do you use for cyclic input?

 

Some joysticks have a "hard coded" dead spot over the mechanical center as well, this may contribute to the issue your experiencing with control. :)

Control is an illusion which usually shatters at the least expected moment.

Gazelle Mini-gun version is endorphins with rotors. See above.

 

Currently rolling with a Asus Z390 Prime, 9600K, 32GB RAM, SSD, 2080Ti and Windows 10Pro, Rift CV1. bu0836x and Scratch Built Pedals, Collective and Cyclic.

Link to comment
Share on other sites

I don't speak about hardware deadzone, because control display move , without action on helicopter pitch or roll.

it is a problem of parameter or/and coding.

 

thanks anyway

 

Okay it has to be a glitch with installed files or a setup problem I use a home made cyclic no center detent but has resistance to movement and a Leo Bodnar USB controller and as soon as I move off the center position of roll and/or pitch there is an immediate and proportional control asserted on the Gazelle roll and/or pitch.

 

I can understand that it would be frustrating, have you tried to un-install and re-install the Gazelle using the DRM management settings??

Control is an illusion which usually shatters at the least expected moment.

Gazelle Mini-gun version is endorphins with rotors. See above.

 

Currently rolling with a Asus Z390 Prime, 9600K, 32GB RAM, SSD, 2080Ti and Windows 10Pro, Rift CV1. bu0836x and Scratch Built Pedals, Collective and Cyclic.

Link to comment
Share on other sites

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...