My 2DOF DIY sim.

oops. ear phones are a cross between ear plugs and head phones

Great job! I must admit when I saw your initial drawing I was a little skeptical if you'll have the stamina to bring it to reality It's certainly a creative new design I have not seen realized here before. What I really like about the construction is that at any failure of the drives, power, etc. you will always return to a safe position.
Well done indeed and now have a lot of fun with the PID!

Thanks, guys.

I have designed it with three different modes. In the racing mode, which it is in now, the center of rotation is positioned way above my head, so roll and lateral movement is connected. The same with pitch and longitudinal. With the adjustment I can move the rotational centers down to my chest area in two steps, which eventually makes the sim rotate around my chest area instead, which I think will be better for flight simulators. I haven't tested those configurations yet though, but all it takes is moving the the rails to the other mounting holes I already prepared.

Here's an illustration of the two end modes achievable by rotating the rails. There's a third mode in between that's an intermediate. The red crossed circle shows the rotational axis.

The left illustration shows racing mode, where G-forces are simulated. The right one shows flight mode, where only rotation is achieved. I don't know if it's a good idea to have this rotational mode, but I wanted to have the option for experimentation. I would have finished the sim a long time ago if I had locked it to just one mode.

As you can see it is front heavy, which is necessary to avoid compromising on the rotational point, so I need to compensate with springs. I have some weak springs on now, but it works. I was going to buy some more springs today, but it's a 50 km drive to the store, and there's a heavy blizzard outside so I won't risk it. I might eventually go for a pneumatic spring system with an reservoir to achieve a constant spring rate throughout the range.

How do I get two functions to act on one axis? Do I add two Output 1:1 (GForce) plugins with the different functions applied to them? I tried that but couldn't get it to work. I want to try roll and lateral G on the same axis, for example.

BTW. The roughness is due to the backlash in the gears. Hopefully It will be sorted when I reduce the backlash.

Yes you are right with add two Output 1:1 (GForce) plugins, I think there are more things you have to change in the configuration otherwise one axis will overwrite the other. I suggest you download some mixed axis profiles , load them up and go over all available options with a fine tooth comb noting an different settings between the Output 1:1 (GForce) plugins for each axis. You will get there after a bit of messing about.

Good idea. I'll look at some existing profiles. I'm guessing it has something to do with the percent of influence to the axis under math setup.

http://www.filehosting.org/file/details ... _Lane.docx
I put in a basic profile creation in this document , hope it helps.
Cheers, David.

Thanks. I got it working now. I had to invert the roll input and reduce the influence. It's bloody awesome now! I just love driving in the up- and downhills on Lime Rock.

I just confirmed that the sim rides just as well with a 93 kg person in it. It works incredibly well now. I can't wait to see how good it gets when I modify the servos further to eliminate backlash and noise.

Here's my friend in the sim: http://www.youtube.com/watch?v=XPU5ROIz ... e=youtu.be

All three LCD screens just died, or the HDMI inpup did. They have been acting weird before. Some of them lost the signal a few days ago and I struggled to get them back up. I tried to connect one of them via DVI, which worked. As I tried to turn them on now they just refused to recognize the signal.

Crap!

And now one of the winches failed. The final pinion is damaged because of too much backlash. I have to stop all operation until I can eliminate the backlash.

They aren't made for this kind of abuse.

Just put it down to learning experience.
Yes this is crap for me too, I was hoping for another video.

Do you think the monitors died as a result of vibration from your sim, I plan on debezeling mine and mounting them in a home made spongy/ foam lined bezel to reduce vibration damage.

I would be surprised if the monitors kaput because of the current use. Monitors tend to suffer more when you twist them, as opposed to shake them.
I had one screen on my old joyrider and it copped some serious shaking, but never twisted.
Did you check your pc and/or graphics cards? Do the screens work on another pc?

As for the motors, have a look at the way you have set them up, maybe you have positioned them so they are under too much load.
It may be a matter of re-designing where the motors are.

screens don like the vibrations at all. but some are good, the main problem is the cabling to the moniter jerking around alot cause the pcb plug normally to break away from the pcb, fix a mates unit on a flight sim we had to take it apart and find the broken pin and simply resolder it, but if under warrenty take it back with no mention of it being mounted on a moving sim.
Plus we made a small bracket to strengthen the plug, solved his problem.

Winches with backlash, i have been thrashing mine for 2 years (600hrs of use) and only destroyed pots must of got a bad batch, plus i found the clutch plates needed welding to strengths the hole in them. but i think cogs can be swapped from the other side. the only place where ya will get any is in the clutch unit but easily fixed.

By the way like the sim motion, mmmm got me thinking. I feel another build on the way, Thanks for the inspiration.

I spent hours checking everything last night. Everything else works. I tried the cables and they work on other monitors. The DVI input on the monitors still works, but they refuse to accept anything on HDMI. I'm scpetical and think the DVI will fail in the same way because...

These monitors have been a bit strange. They turn off and on again if I power up the power supply for the Thrustmaster wheel, or turn on the vacuum cleaner, so I guess the power supply lets all sorts of crap through. The other set of desktop monitors that are connected to the splitters still work, and have never exhibited this behavior. I tried switching over the splitter outputs and both outputs work.

I have contacted the shop I bought them from (komplett.no).

I will buy another winch for spare parts and stop operation until I canreduce the backlash. The gear mesh is very loose on these things, which is a disaster. The gears are also made of a very weak steel, which is as easy as aluminum to drill. I have also neglected to lubricate the gears, which is just my own stupidity. The gear failure doesn't bother me much. It's just part of the challenge, but the monitors failure is really annoying.

I would love to add two more axis for lift. One for the left side and one for the right side. I want to raise and lower the rig according to vertical G/bumps and provide violent short range tilting when I run over the curbs.

I turned the damaged pinion around so that the contact area is on the good half, and lubricated them. I can ride it now, but I have reduced the acceleration and duty cycle to lessen the load until I can improve the gear mesh. I still love racing up and down hills in iRacing. Hehe

Regarding the load. Due to the centering design it takes very little force to move it around near the center position, but it becomes progressively more difficult towards the ends. I estimate that it takes ~25 kg to move the pitch axis fully forward with an empty machine, a little more with me in it. Still, I set the Jrk up for 25 A max, which feels as fast as unlimited and it only exceeded the max current once during a long testing session. I have a small heatsink on each of the big chips, and a silent 80mm fan, and the Jrk doesn't get hot at all.

Maybe I should mill an aluminum gear for the output gear and double it up with the stock steel gear. That would help spread the load a little, but not as well as a second steel gear would. I'm pretty confident that adjusting the gear mesh will do wonders for the winches though. The simulator weighs 100 kg now. That's a lot of mass to accelerate when the servos change direction.


Today I tried changing the rotation point by tilting the roll rails. I can't change the pitch rails yet because the servo rod underneath will bind, but that's an easy fix once I get to it. In flight mode I got seriously dizzy after just a couple of corners because it's tilting me +-16°. That mode puts the rotational point in my chest area. The intermediate mode worked well for racing though. In this mode the rotational point is a short distance above my head, giving a little more rotation, and a little less lateral movement than the racing mode.

I'm uploading a video now that will be available later. It's pretty bad quality, but it shows the sim off pretty well.

Here it is. In this video the roll axis is in intermediate mode. http://youtu.be/5xovwtKTFkE