Honey, I developed FFB joystick (DIY)

[flyingtux]

12 hours ago, propeler said:

There is good chance for it 

 

I ordered part from local polish companies. https://ajmaker.pl/produkt/ciecie-laserem/ for metal parts and https://rapidcrafting.com/en/ for 3d prints. Not sure if they are international.

 

Not much yet. But I will make. What do you whant to see in it? 

thanks Propeler

[trigen]

Fantastic work! Ill be building one asap to replace my MSffb2 

[SquidgyB]

Progress so far on mine - gimbal and joystick mechanics are done, just finishing off wiring for the end point hall sensors then I'll be looking at the software side with a view to running the joystick as a "standard" joystick with no force feedback for the time being, just using the hoverboard motors for centering (so I can continue flying!) and moving on to full force feedback soon^tm.

I had issues using the SPI bus on the TLE5012B encoders I have, so they're currently working as ABI rather than absolute - also I've had issues updating the firmware on my ODrive (which may or not be related to the SPI issues), but I now have an ST-Link V2 so I'll try updating the ODrive to the latest firmware soon.

 

I'm between two minds as to using the ODrive entirely for the electronics, or adding an Arduino as the interface between the PC and ODrive and running the ODrive via PWM signals (or other communication, maybe UART?) - currently only two motors are powered, but if my plans come to fruition, I'm thinking of using one motor on each axis for the centering force, and the second motor on each axis for impulse forces, but I'm not sure if/how that would work.

 

Bootup and centering for now will be using end stop hall sensors and the index of each live motor mechanically set to the center point of each axis as I do not have an absolute reading on the encoders.

 

The pedals were also DIY, from a few years ago - still running strong

 

Edited June 28, 2021 by SquidgyB

[propeler]

22 hours ago, SquidgyB said:

Progress so far on mine - gimbal and joystick mechanics are done

Show it to us :)

[SquidgyB]

1 hour ago, propeler said:

Show it to us :)

 

No problem , thanks for your interest!

 

Here's a short video, taken before I put the hall effect end stops in - so no wiring in the way. The motors here are just stators on bearings and are not locked into the mounts, but still it demonstrates the geometry movement fine.
 

 

I get around +/-22.5 degree movement on each axis, all the way up the diagonal, though the joystick itself will be limited to +/-15 degrees, so movement is free (and very solid) all the way through the range. The motor shafts are 16mm, and the central gimbal shafts are 8mm, held by triple bearings on each end of each shaft (4 bearings on the top and bottom end of the central "Z-axis" "wiggle shaft" as I like to call it - it is a little over-engineered).

I need to take the gimbal stack out to re-calibrate one of the motors in the next few days, so I'll try to get some beauty shots at different angles to show the mechanism, but it's basically an expanded MS FFB2 gimbal made with aluminium and bearings, with all shafts held by bearings on both ends to ensure absolutely no slop/play in the mechanism.

[propeler]

Can you share more details about how core (central part) of gimbal is made?  How many parts need to be machined?

[SquidgyB]

4 hours ago, propeler said:

Can you share more details about how core (central part) of gimbal is made?  How many parts need to be machined?

 

It was a bit of an iterative process, so not as simple or straightforward as it could have been as I was trying to re-use parts and materials I had to hand as well as parts I purchased which didn't really turn out to do what I wanted them to...

Top and bottom are a linear bearing shaft mount for an 8mm shaft, with the bearings knocked out (they didn't allow smooth rotational movement) - I used a small lathe to turn the inner diameter of an aluminium tube to slot snugly over the linear bearing mount and allow bearings to fit snugly in the tube (the tube and shaft is what I'm holding to move the gimbal). Between the two linear bearing mounts are two 8mm x 25mm x 25mm blocks of aluminium, with a central 8mm hole in each 25mm x 25mm face and 8mm shafts press fitted/JB welded into the holes - these form the "x" axis, whereas the "y" axis is also an 8mm shaft vertically (going through the linear bearing mounts) with a shorter 8mm shaft (the actual "y" axis) soldered and JB welded across perpendicularly.

 

The two 8mm x 25mm x 25mm blocks are then sort of chamfered on the inside to allow the "wiggle shaft" to rotate just enough to allow the gimbal to not lock on diagonal movement (my original design using the propshaft spider fell foul of the same issue you encountered in your first attempt, I believe - locked to the cardinal directions and no diagonal movement at all).
 

The design is fairly symmetrical top and bottom, but the whole thing did need a bit more machining than I initially intended, but as you can see from the pedals, I'm not scared of a bit of DIY fun times (and it "allowed" me to justify the purchase of a small lathe, much to my partner's chagrin! :D)

When I get the gimbal out later I'll post some pics as I think that will help a lot with the explanation above...

Overall, in terms of machined parts, the internal SK016's (the four on the central gimbal part) needed some chamfering on the corners and rounding of the top of the mounts, a pair of aluminium tubes needed the internal diameter changed to slot over the linear bearing mounts, and also to a different diameter to hold the bearings. The main 8mm x 60mm x 120mm blocks needed the central portion removed (a hack job, as you can see), and then some minor modifications to the bottom ends of the aluminium tubes to allow nut/bolts to fit correctly. Some parts needed a little squeeze in a vise to get clamping force on the bearings and motor shafts, and a few aluminium can shims to shore up loose bits... Also the 8mm shafts for the "wiggle shaft" were ground in a curve down to 1/2 of the shaft diameter, then soldered together and finished with JB weld fillets/fill in for a secure and strong bond.

 

e: Here's a video of the gimbal core, hope you can make out some more details of what I've done there:

 

 

Edited June 29, 2021 by SquidgyB

[Milan MFG]

Guys...I must say I am impressed by this thread, and not only by one builder - but all three builders ! The way you managed to combine knowledge from different engineering branches on a very complex project is just breathtaking !

I always dreamed of building such stick and still have some ideas that simplifies your design but for me ARM was uncharted water, I didnt find a proper motor, PID controller done right is beyond me...and FFB licencing issue (expired last year) was a "no-go" reason for me. Plus nobody was asking for FFB past few years, it was like idea was dead :-))

You guys entered this project in just about right time with right set of skills. I am eagarly awaiting to see your final word here. If you ask me :

- definitely aluminum or bent sheet metal gymbal components

- need to go aroun 4-5kg force at 20cm extension at least

- maybe MLX90380 3axis hall ...and sensor/encoder holder should be simplified

...

Edited June 30, 2021 by Milan MFG

[Dirt_Merchant]

On 6/30/2021 at 11:50 AM, Milan MFG said:

Guys...I must say I am impressed by this thread, and not only by one builder - but all three builders ! The way you managed to combine knowledge from different engineering branches on a very complex project is just breathtaking !

I always dreamed of building such stick and still have some ideas that simplifies your design but for me ARM was uncharted water, I didnt find a proper motor, PID controller done right is beyond me...and FFB licencing issue (expired last year) was a "no-go" reason for me. Plus nobody was asking for FFB past few years, it was like idea was dead :-))

You guys entered this project in just about right time with right set of skills. I am eagarly awaiting to see your final word here. If you ask me :

- definitely aluminum or bent sheet metal gymbal components

- need to go aroun 4-5kg force at 20cm extension at least

- maybe MLX90380 3axis hall ...and sensor/encoder holder should be simplified

...

 

 

What an endorsement!!

[sockeye]

Hey guys, new here. LOVE this thread. Thank you to the giants that got the ball rolling here. Love the idea of direct drive hoverboard motors because they are cheap and powerful. I'm dabbling with the idea of building a p51 simpit, and think it would be best for my design if the motors were under the seat.  In the p51 drawing below, you can see the arrangement of the controls. They didn't use a 2 axis gimbal like a HOTAS joystick does, the roll and the pitch pivot points are on two different planes (pitch axis is at the the bottom and roll axis is 115 mm above). I think this could lead to a simpler/cheaper/strong design for hoverboard motors than a 2 axis gimbal. 

 

I'm not sure I like my design yet, but I wanted to share it with you all for feedback.. I'd like to 3d print most of the parts, use a single cheap bearing size for all the pivot points. The stick shaft would be 30mm extruded aluminum and I'd put a Thrustmaster warthog adapter at the top of the stick. But in my case, I plan to print a custom ww2 style joystick that is tm wh compatible. The case would be made of interlocking laser cut 3mm mdf or just sheet metal like @propeller26 is using.. not sure yet. The total case height would be about 200mm or 8" (the real p51 has about 8" between the seat bottom and floorboard, so it would just fit.) 

 

I would appreciate your feedback. You all are obviously more capable engineers that me.

 

Edited July 4, 2021 by sockeye
typos

[TomVR]

I tihnk you'd still want the belts for gear reduction and also safety. (belts will slip before your wrist will dislocate) 

[walmis]

Hey guys, a little demonstration on how the anticogging works on my motor drivers:

 

I also made an interesting finding - most hobby grade motors are wound using the the Delta winding termination, I reterminated my motors using the Wye(star) pattern, and gained 1.7x more torque per Amp for free  So essentialy a 170Kv motor is now 98Kv motor using Wye termination.

 

Edited July 5, 2021 by walmis

[sockeye]

@walmis this is great!  I wonder wye (pun) hobby motor designers would use the less powerful delta winding? What are the trade-offs? Probably higher current draw (and faster battery use) with wye?


 

Edited July 5, 2021 by sockeye
formatting

[sockeye]

I tihnk you'd still want the belts for gear reduction and also safety. (belts will slip before your wrist will dislocate) 

I agree on belts for safety. It is my assumption that the hoverboard motors don't need gear reduction as they are so strong. I guess if I am right about that, the need for belts might be even greater...

That said, as I am reworking my design for under seat motors, it appears that smaller motors with grear reduction might be preferable anyway. The 6.5" diameter bell housing is tough to fit in a small package. And motors with grear reduction will obviously provide much higher resolution on the encoders.

Sent from my moto g(6) using Tapatalk

[walmis]

1 hour ago, sockeye said:

@walmis this is great! Do you plan to share your driver code and case STL files anywhere yet?

Yep, working towards that.

 

1 hour ago, sockeye said:

Are you using the @propeler  gimbal?

Yes, actually I'm building another (more simplified) FFB joystick base based on propellers' gimbal. 

1 hour ago, sockeye said:

Which motors are you using? Your force numbers were impressive. Even better now with 1.7x more torque.

Those force numbers were with my other FFB base, that one is based on 57BLF03 which for the price provides quite nice torque. For the ~50EUR motors, I think these are the winner for FFB. Also that FFB base has more reduction gearing, so that adds more torque to the stick.

 

For propellers variant i used these motors, reterminated with Wye termination. Gonna test torque output later

 

1 hour ago, sockeye said:

I wonder wye (pun) hobby motor designers would use the less powerful delta winding? What are the trade-offs? Probably higher current draw (and faster battery use) with wye?

From my understanding delta winding is more simple to manufacture, hence lower price and most hobby motors need more RPM, so that's a bonus. Power output is the same for both windings, just the torque/RPM characteristic is different. Our FFB application is different, because we operate in the zero RPM/max torque area, which means lower Kv the better. Also there is another tradeoff - high Kv motor - more current for same torque, more power is dissipated in MOSFETs. Low Kv motor - less current for same torque - more power is dissipated in the motor windings because of higher winding resistance.

[sockeye]

2 hours ago, walmis said:

For propellers variant i used these motors, reterminated with Wye termination. Gonna test torque output later

Oh my... So these are 170KV motors for $28.20 with Hall sensors included??? I can get them on ebay shipped for $48/ea. My guess is that these cheapo motors are only usable because of your de-cogging controllers (which are AMAZING!). AND re-terminating them to wye makes them 1.7x more powerful? You are DEFINATELY on to something here. I'm just ordered a pair of these now as they are so cheap and shipping from China is a month out. 

 

Edited July 5, 2021 by sockeye

[98abaile]

If wiring them in a Y configuration increases the power, it would also be nice if we could use smaller motors in a smaller package.

[walmis]

Hey guys, another force test:

 

This time with propellers' gimbal variant. To be honest I'm surprised it managed to pull this much with single reduction gear.

6374 170KV motors, Wye windings

~23 phase amps (Q current in FOC terms) into the motor shown above at maximum.

 

Edited July 6, 2021 by walmis

[Phantom_Mark]

3 minutes ago, walmis said:

Hey guys, another force test:

 

This time with propellers' gimbal variant. To be honest I'm surprised it managed to pull this much with single reduction gear.

6374 170KV motors, Wye windings

~23 phase amps (Q current in FOC terms) into the motor shown above at maximum.

 

 

Is this something you will ever offer as something we could buy, or should I just go ahead and buy a flawed Brunner instead? 

[walmis]

2 minutes ago, Phantom_Mark said:

Is this something you will ever offer as something we could buy, or should I just go ahead and buy a flawed Brunner instead? 

 

Yes, that's my goal  I'd like to make this my full time operation, but currently I only develop/build during my spare time. Who knows, maybe this will grow into something bigger. Gotta quit my day job first LOL.

Btw, what flaws does the Brunner have?

[Phantom_Mark]

1 minute ago, walmis said:

 

Yes, that's my goal  I'd like to make this my full time operation, but currently I only develop/build during my spare time. Who knows, maybe this will grow into something bigger. Gotta quit my day job first LOL.

Btw, what flaws does the Brunner have?

The only thing the Brunner has is that it "exists", I've heard it can overheat at full duty cycle, the drivers are not DirectX compatible / plug and play either, its hardly a realistic option to replace my modded MSFFB2 ......which is what I want to replace ASAP, buying a Brunner will be a sad turn of events

I am in the market for a worthy replacement the moment something appears.

Edited July 6, 2021 by Phantom_Mark

[propeler]

1 hour ago, walmis said:

Yes, that's my goal

Read the license :) https://creativecommons.org/licenses/by-nc-sa/4.0/

[walmis]

14 hours ago, propeler said:

Read the license :) https://creativecommons.org/licenses/by-nc-sa/4.0/

Well, I definitely don't plan to use your work for commercial purposes  

[frumpy]

If you are willing to share - I am waiting eagerly for a complete manual with all STLs, parts and software to start my own project. I feel a FF-stick can add so much to the realism... but before spending $200 on parts and not knowing exactly what to do, I rather wait.

Keep it up!

[sockeye]

I've printed@propeler 's gimbal and ordered the bearings. I've ordered the 180kv motors that@walmis suggested.

I got a couple of quotes for the sheet metal in@propeler 's design. $300+ here in the us! The tapped holes add a lot of labor cost because they can't be plasma drilled and then tapped due to metal hardening. So they have to be manually placed, drilled and tapped. Doubling the cost. No good.
@walmis are you willing to share your mdf case stls or should I design something similar for myself?

Also@walmis I suspect your board design will work with those new motors just fine? If so I'll order a couple of them for myself so you can have another "tester".

I'm so grateful for all the work you guys have put into this. Can't wait to get another ffb stick up and running!

Sent from my moto g(6) using Tapatalk