My 2DOF DIY sim.

Good to hear! How did you modify and improve the gear? By replacing the bearings? Most of my backlash is coming from the gear too and I'm thinking of replacing the bearings with proper ball bearings or so. I would be interested to hear how exactly you reduced your backlash.

I replaced the sloppy bearings with new ones that have a slightly smaller outer diameter. Then I made eccentric bearing cups for them so that I could adjust the gear mesh by rotating the cups, and lock in place with a screw. I also made a clamping hub for the shaft flange to eliminate play there.

The air system is airtight. It has been holding 4,5 bar for days now.

I'm struggling with eliminating the final piece of play in the drive train. The final stage pinion keeps coming loose from the hex flange. It's not exactly a precision fit. I have tried loctite 609, which is the only loctite I have, along with tightening it until I see red. I'll have to figure something out if it continues. I will also make new output arms from aluminum with an integrated half gear to improve the rigidity of the assembly. Maybe I can use aluminum for the pinion as well and create a tight fitting gear with a locking mechanism.

I broke one of the new output shaft bearings in the pitch when I forgot a spacer, and over-preloaded it during initial assembly. That was stupid. Luckilly I had one spare. but I will order more and double them up to increase the load capacity.

Here's a drawing showing the principle of the eccentric bearing cups. As I rotate it, the shaft is moved left or right (and up and down, but that doesn't matter). Smaller holes around the flange let you lock it down in steps with a couple of screws. To adjust, remove the two screws and rotate until the next hole to bring the gears closer together or farther apart.


I'm finishing the installation of the air tanks (two 1,5 l Coca Cola bottles) now. Up until now I have been running with one bottle and connections outside the sim, for testing. This resultet in ~25% change in pressure throughout the range, making the spring force constant 36 kg +-4 kg. (~1 bar change @ 4,5 bar pressure). With two soda bottles it should be about half that, so nearly a linear force all the way through the range. This is the reason an air spring is great for this. My bottles, will be hidden under the seat platform, with the gauge and filling valve sticking up behind the seat, so it's not visible from the outside.

Here's a view of the rear. The cylinder housing is sticking out. It moves with the pitch axis. I will remove the connector on the end as I don't need it. The soda bottles sit just under the seat plate, in front of the pressure gauge. In the top right corner of the picture you can see my home made helicopter pedals, modeled after our Westland Lynx pedals, with a hydraulic damper for smooth resistance. I can't wait to try them in X-plane with the stick I plan to make.

I have pressurized a lot of soda bottles to over 9 bar lots of times before without a single failure back when I made a bottle rocket launcher. They can handle a lot of pressure before they burst. Next to the pressure gauge is the connector for filling with a regular tire filling gun.

I have a new, nice carpet for the floor under the sim to replace the nasty one that's there now, and will bring it out when I'm happy with the servos, as I make a dirty mess on the floor every time I have to work on them. I think I will use spherical bushings for the output shaft this time as they are self aligning and can handle a lot of force.

groovy

This link will lead to a new video of the sim when it's finished uploading in a few hours: http://youtu.be/fT61BFrRL-M

The squeaking sound at the end is probably due to a bent hinge on the right front side. I haven't looked closely at it since I shot the video. That hinge tends to bend due to the geometry of the basic hinges I used. It has bent twice before and I just bend it back. I know how to strengthen it, I just have to get off my bum and do it.

The excessive backlash in the servos in the beginning caused the pitch axis to overrun the rails, and jump out of the rear end. This damaged the bearing trucks, which is probably why it clocks occasionally. Some balls are missing. I have ordered a couple of new bearings (at $8 a piece) which should fix it.

The motion feels really good.

Thats Great movement there! Marvelous!
As you said, constant adjustments and slight improvements.
We are all getting there, goodness knows, I put 5 turn pots on mine from single turns, now I have to re-adjust profiles and PID.
Go hard!

Thank you tahustvedt for the explanation. I just ordered 2 sets of imperial quality ball bearing for the two first axes of my winches.
Thx for your video! (Glad, you don't wear white socks! LOL)
Great achievement in only 2½ months, especially when considering all the elements you built in!

I really love the motion of your sim!

And good to see it evolve this fast and you getting all the bugs out (it's all about trial and error, where's the fun without it ).

Whish my progress would be this fast, but I'm lucky if I can spare a few hours a week on my sim amd I only have a bench press to work with

KUTGW!

Thanks. It's been a fun experience building this sim, but it's not finished. I'm still not decided on wether I should make a lift axis.

Here's what I made today. It's a new output arm with an integrated gear. The gear teeth are 8 mm thick, and much smoother than the steel gears. Hopefully it will last. I found some bearings I can use and will make a new shaft. I needed something that is stiffer than the stock gear setup as it was working itself loose. The shiny surface pattern you see on the gear part is actually smooth despite the look. This is what it looks like straight after machining. The reason CNC-machined parts that you can buy don't have these patterns is because of post processing/polishing that is done. I had to mill down that surface so that the small tools I use to make the gear teeth can reach. They are just 9 mm long, and will crash if I don't think out the 15 mm slab first.

Do I have the longest servo arms in the sim community?

Really impressive vid... all the frame, the movement, the general view of your simulator smeels of professionality. The 3 monitor system is not easy to build and seems perfect dude.
Seems a thing ready to enter in the market instead a DIY thing!
Maybe the best 2dof I seen and a great motivation to this comunity to do always better! :adore:

Thanks. :

Simply an amazing simulator what can I say, and your driving is superb with motion too.

One thing to suggest, have you tried changing your Field Of View, 3 LCDs you have an advantage of setting this lower and getting a more accurate lifelike perspective but I guess its what your most comfortable with. Since I changed to using 3 LCDs my I adjusted my FOV to calculated correctness you can do that using the tools here http://isiforums.net/f/showthread.p...rFactor-FOV-Tutorial?p=311&viewfull=1#post311

Actually I want the FOV as high as possible because I think the sense of speed is too low. It's as high as it will go now at 179°. The picture is not distorted as it's just 60° horizontal FOV (~34° vertical I think) per monitor. iRacing doesn't stretch one view across three monitors like most other sims, it can render three views for undistorted triple screen racing.

When I'm plaing the monitors is my world, so my vision is sort of limited by my mind to what happens on screen.

You got me thinking about my monitors now. I should make new brackets to angle the side monitors slightly inwards towards myself to achieve the same distance to each monitor. Right now the centers of the side monitors are 5 cm farther away. The center monitor is 70 cm from my eyes. The actual field of view covered by the monitors at the moment is 120°. Maybe I'll move them all closer as well. I had already prepared mounting holes for the monitor stand to move them 20 mm closer, but drilling more holes in the MDF is a quick operation.

Earlier today I actually looked at larger monitors on the internet. Samsung has a nice 32 TV with ultra thin edges that weighs just 5,7 kg. That's lighter than my current monitors weigh each. I'm worried that 1920x1080 will be too low with such big screens though, plus they cost four times as much as the ones I have now. Maybe I should just be happy with what I have for once and fix something that doesn't work properly instead.

When it breaks , then fix. :thbup:

Just another thought, today I looked at a friends simulator that is of similar design and he uses golf buggy motors for movement, similar to the motors I have. He finds them very strong for rapid changes of direction. He had looked at winches, but found them to be of hassle.
Still, you have made changes to your motors, so give them a thrashing and see how they go.
:clap:

I changed to a low FOV and found it weird, gave it a chance for a week and never went back, you can see more of whats going on infront of you plus detect the micro left and right movements of the car better. Try for one week, your approach to corners and exits will be better after a bit of getting used to. plus other cars look nicely big and scaled http://www.youtube.com/watch?v=oWV0_u0r-Hk

tahustvedt what kind of monitors? ] I dont know if you may be comfortable with doing this but I recent test debezeled mine and found it very easy altho I found theres no vesa mount on the internals means Im going to have to build a custom support casing. With my Benq LEDs all I had to do was prise away very carefully to remove the front bezel. Heres some pics