good bye re-center dance or how i added force trim to my joystick

[mue]

Inspired by this

 

http://forums.eagle.ru/showthread.php?p=1586007

and this

 

http://forums.eagle.ru/showthread.php?t=50522

 

I decided to add force trim functionality to my x52 joystick.

 

The result you can see here:

 

 

 

 

For the spring mechanism I used rc car dampeners. I removed the silicon oil and the seal rings to eleminate the dampening effect and any friction. Then I replaced the original spring with a shorter one and fixed both ends of the spring to the dampener. Now the spring acts in push and pull direction.

 

 

 

The clutch is made up of a drawer slide, a steel bar and a holding magnet (and some wood for the frame/base). Electric holding magnets are available with different holding forces. The magnets I use have a holding force of 100 N.

 

 

 

The lower part of the drawer slider is bolted to the wood frame. The upper part is attached to the metal strip and to the dampener. The magnet is placed on the steel bar and fixed to the wood frame so that it can not move in the horizontal direction. If the magnet is unpowered, the steel bar can slide under the magnet. If the magnet is powered, the steel strip is clutched by the magnet.

 

 

 

To make this force trim construction work properly, the joystick has to be "balanced". "Balanced" means that the center of gravity of the stick should be in or near the gimbal joint of the stick. The CG of the x52 stick is above and slightly in front of the gimbal joint. Therefore I made a hole in the bottom of the x52 casing, extended the stick tube and attached a counter weight.

 

 

 

The next picture shows the electrical part. It takes the signal from the joystick button (the trim button) and via an optokoppler and a relay the magnets are unpowered (trim button pressed) or powered (trim button unpressed). It means that the magnets are powered most of the time. Unfortunately powered magnets are getting hot. So probably I have to add some heat sinks. I still have to make some long time testing.

 

 

 

In the following picture you can see the connection of the dampeners with the stick and the disabling of the center spring.

 

 

 

For using the force trim joystick with DCS:Black Shark I had to change the in game trim behavior by

1.) disabling the center trim method and

2.) setting in FMOptions.lua HelicopterTrimmerTauInverse=0.0

[agrasyuk]

very good idea, thumbs up

 

ADD: actually gives me an idea..

Edited January 14, 2013 by agrasyuk

[Suchacz]

Wow! Just... WOW!

[Dusan56]

Very cool man. Like it.

[Devrim]

Wow! Great!

 

But, how do you reset the trim?

[mue]

very good idea, thumbs up

 

ADD: actually gives me an idea..

 

That's what the forum is for isn't it?

[mue]

Wow! Great!

 

But, how do you reset the trim?

 

It has no special reset trim button. To reset the trim you have to center the stick and press-release the trim button.

[walker450]

WOW!!!!! GREAT JOB!! That is awesome!!!

[sungsam]

Great Work !

 

Since you have extended the stick tube and attached a counter weight, why dont you bind the dumpers there along with magnets and etc mechs and enclose them in a box. That way you will have a clean original configuration above.

[mue]

Great Work !

 

Since you have extended the stick tube and attached a counter weight, why dont you bind the dumpers there along with magnets and etc mechs and enclose them in a box. That way you will have a clean original configuration above.

 

Yes, it's a good idea.

My construction is kind of "historically grown":

First I built the damper/magnet mechanism in the (for me) easiest way as possible: beside the joystick. Only then I realised that the stick needs to be balanced and I added the counter weight. But at this time I was just too lazy to rebuilt the damper/magnet mechanism.

[Shaker]

Down right impressive.

[JG14_Smil]

Hello Mue,

 

Just wondering how things were holding up.

 

Did you do anything about the heat issue you spoke of?

 

Any issue with magetising the metal bar or with metal shavings?

 

I'm trying to imagine a way to reverse the magnet's action to release the brake when activated. It would have to overcome a pretty stout spring force though. I just thought it might be better that way if heat buildup was an issue with the magnet enabled so much.

[walker450]

Can you explain how you are trimming the chopper in-game? I'm a little confused with this... If you hit the trimmer in-game it expects the joystick to return to center, but yours won't since the joystick itself trims to center

 

EDIT: I re-read your post and seen where you changed game settings to force trim.

 

Nice work!

Edited February 18, 2013 by walker450

[mue]

Did you do anything about the heat issue you spoke of?

 

No, I haven't added heat sinks yet. The magnets are rated for maximum temperature of 130 degrees celsius. I had the magnets powered on for 2 hours and although they are getting really hot I think they are way below maximum temperature. However the holding force of electro magnets decrease with increasing temperature. But I haven't noticed that in my construction. So likely I leave it without heat sinks.

 

Edit: I made some temperature measurements: After 1 hour the magnets reached a temperature of 40 degrees celsius.

 

Any issue with magetising the metal bar or with metal shavings?

Metal shaving occurs, but it's minor. I think (actually hope) it's not a problem in the long term.

What do you mean with magnetising the metal bar? I can't think of any problems with it.

 

I'm trying to imagine a way to reverse the magnet's action to release the brake when activated. It would have to overcome a pretty stout spring force though. I just thought it might be better that way if heat buildup was an issue with the magnet enabled so much.

I also thought about reversing the clutch mechanism, but I haven't found an easy solution. Edited February 18, 2013 by mue
added result of temperature measurement

[CyBerkut]

Inspired by this

 

http://forums.eagle.ru/showthread.php?p=1586007

and this

 

http://forums.eagle.ru/showthread.php?t=50522

 

I decided to add force trim functionality to my x52 joystick.

 

....

 

The next picture shows the electrical part. It takes the signal from the joystick button (the trim button) and via an optokoppler and a relay the magnets are unpowered (trim button pressed) or powered (trim button unpressed). It means that the magnets are powered most of the time. Unfortunately powered magnets are getting hot. So probably I have to add some heat sinks. I still have to make some long time testing.

 

[ATTACH]75935[/ATTACH]

 

 

For using the force trim joystick with DCS:Black Shark I had to change the in game trim behavior by

1.) disabling the center trim method and

2.) setting in FMOptions.lua HelicopterTrimmerTauInverse=0.0

 

This is a great modification! :thumbup: I've been meaning to ask about it, but now with the Huey module out, it has taken on more priority. :)

 

Can you provide more information on the optical coupling and where you are picking off the signal inside the stick?

 

The disabling of the center trim method makes sense, after all, that is what the mod is all about. I guess I'll need to look into the HelicopterTrimmerTauInverse=0.0 as I don't know what that is doing. :book:

 

If you still want to look at reversing the clutch action, where your magnets would be energized while depressing the trim button, I think you could accomplish that with:

 

1. Remove the magnets from their current mounted positions.

2. Place traction tape (like what skate boarders use, or what gets put on outdoor steps to prevent slips and falls) on the top of the clutch bars that your magnets have been clamping on to.

3. Fashion another bar to sit above your existing clutch bar, oriented across it at a 90 degree angle. Have the bar hinged to pivot on one end, with a spring holding it pressed down upon the existing clutch bar. Put traction tape on the underside of that pivoting bar, where it crosses the existing clutch bar. Traction tape on both bars will engage, which should be enough to stop the drawer rail from sliding.

4. Mount your electro magnet above the pivoting bar, so that when energized, it pulls the pivoting bar up, away from the existing clutch bar. Traction tape on both bars will disengage, which should allow the drawer rail to slide. You might find it better to locate the magnet mount so that it is not directly above the existing clutch bar, in order to ensure it doesn't cause the existing clutch bar to lift.

5. Repeat for the other clutch bar assembly.

6. Swap your circuit control scheme to energize the magnets when the trim button is depressed.

 

Alternatively, what I might do, is something similar, but utilizing solenoids instead of electromagnets... as you can get them to mechanically actuate with power off, or power on, as whatever the design needs.

 

I'd actually like to do it for both the cyclic, and the pedals.

 

Anything you could share on picking off that signal inside the stick, and the circuit you used for the magnet control, would be appreciated!

[Ranger79]

Awesome stuff man!

[sylkhan]

Great work!

 

Anything you could share on picking off that signal inside the stick, and the circuit you used for the magnet control, would be appreciated!

 

+1

[TimeKilla]

Amazing buddy! :thumbup:

 

Hardcore Sim badge is in the post.

[CyBerkut]

Does anybody on here know of an alternate way (besides these forums and the built-in PM syatem) to contact Mue?

[mue]

Does anybody on here know of an alternate way (besides these forums and the built-in PM syatem) to contact Mue?

 

Sorry for being not responsive, but real life cropped up: the birth of my daughter :). I will try to answer your questions within the next days.

[CyBerkut]

Awesome news! Congratulations on the new daughter!

 

You get to it when you get to it. I'm glad to see you're still popping on to the forums. :)

[mue]

The disabling of the center trim method makes sense, after all, that is what the mod is all about. I guess I'll need to look into the HelicopterTrimmerTauInverse=0.0 as I don't know what that is doing. :book:

By unchecking the center trim method option the "old" trim method is used. With the old trim method there is a short delay (fraction of a second by default) until the trim setting takes effect after releasing the trim button. By changing the HelicopterTrimmerTauInverse value you can change this trim delay time. With HelicopterTrimmerTauInverse=0.0 the trim delay time is set to infinity. That means the trim setting never takes effect and you are not forced to center the joystick. However the autopilot will still be set by releasing the trim button.

 

Anything you could share on picking off that signal inside the stick, and the circuit you used for the magnet control, would be appreciated!

Unfortunately I didn't make a picture from the dismantled joystick where I soldered the wires to the circuit board. I connected one wire to the electrical ground. The other wire I connected to the proper pad (joystick button) on the circuit board in the joystick grip where I get a voltage of 3.5 - 4.0 V (I don't remember the exact number) if the trim button is pressed and 0 V if the trim button is unpressed.

With that signal you can not drive the magnets directly (the magnets use a voltage of 12 V and the needed current for both magnets (0.6 A) is to high to be powered by the joystick).

Probably you can use this signal directly to control a relay that turns the magnets in the 12 V circuit on and off. However I added an optocoupler between joystick and relay to further minimize the current load on the joystick:

forcetrim.BMP

[CyBerkut]

By unchecking the center trim method option the "old" trim method is used. With the old trim method there is a short delay (fraction of a second by default) until the trim setting takes effect after releasing the trim button. By changing the HelicopterTrimmerTauInverse value you can change this trim delay time. With HelicopterTrimmerTauInverse=0.0 the trim delay time is set to infinity. That means the trim setting never takes effect and you are not forced to center the joystick. However the autopilot will still be set by releasing the trim button.

 

OK, that makes sense. I'm thinking that just selecting Force Feedback Mode should accomplish making centering a non-issue, but if it doesn't work then your method should definitely get it done. :)

 

Unfortunately I didn't make a picture from the dismantled joystick where I soldered the wires to the circuit board. I connected one wire to the electrical ground. The other wire I connected to the proper pad (joystick button) on the circuit board in the joystick grip where I get a voltage of 3.5 - 4.0 V (I don't remember the exact number) if the trim button is pressed and 0 V if the trim button is unpressed.

With that signal you can not drive the magnets directly (the magnets use a voltage of 12 V and the needed current for both magnets (0.6 A) is to high to be powered by the joystick).

Probably you can use this signal directly to control a relay that turns the magnets in the 12 V circuit on and off. However I added an optocoupler between joystick and relay to further minimize the current load on the joystick:

 

OK, that is helpful, and thanks for the circuit drawing. By any chance, did you keep a list of what values you used on the various components?

 

So, if I understand this correctly, you wired in to the joystick button up in the grip where it is connected to the circuit board inside the grip... and you were able to pick that signal up without interfering with the button's normal function in the game/control panel. Very nice! :thumbup:

[mue]

OK, that makes sense. I'm thinking that just selecting Force Feedback Mode should accomplish making centering a non-issue, but if it doesn't work then your method should definitely get it done. :)

Unfortunately just selecting FFB mode doesn't work if you don't have a FFB device connected to your computer.

 

OK, that is helpful, and thanks for the circuit drawing. By any chance, did you keep a list of what values you used on the various components?

optocoupler: sfh610a-4 http://www.vishay.com/docs/83666/sfh610a.pdf

(notice: in comparison to my schematic the pins 3 and 4 on this optocoupler are swapped)

relay: sy-12w-k http://www.fujitsu.com/downloads/MICRO/fcai/relays/sy.pdf

magnets: its-ms-3025 12v http://www.red-magnetics.com/download/datenblatt/redmagnetics-datenblatt-its-ms-3025.pdf

R1: 330 Ohm

R2: 1 kOhm

LED: standard led (U=1.6V, Imax=20mA)

D1: 1N4148

D2: 1N4001

 

So, if I understand this correctly, you wired in to the joystick button up in the grip where it is connected to the circuit board inside the grip... and you were able to pick that signal up without interfering with the button's normal function in the game/control panel. Very nice! :thumbup:

Yes, correct.

[CyBerkut]

Superb!

 

Thanks, mue!