My 2DOF DIY sim.

ah yes, but how much does the cnc machine cost?

And everybody should have dreams as well and yes, a CNC router is a dream of mine as well (has been for years allready, from the very moment I started my XIXIV casemod project and it would have saved me a lot of work on my Core4 project as well which I'm planning on finally picking up again after finishing my sim, although routing all panels by hand was quite fun to do).

They are just so damn expensive

Ontopic: Love your work! And the movement of your sim looks very good, compliments on the new design!

Not sure. A rough estimate using todays prices ends up at ~1000 USD for all the mechanical parts, spindle, steppers and a budget stepper controller, like the one I used when I built it in 2007. Add to that small bits like cables, micro switches, materials and the PC, and you have a machine. If, like me, you have some of the stuff lying around, then you're almost set. The machine parts (rails, screws) can be found on ebay for next to nothing if you're willing to wait until the good deals pop up. It took months until I had all the parts I needed, but it didn't matter because I was going through several design stages in CAD.

Over the years I have made upgrades to the machine. The G540 costs $299, and I recommend springing for one of those, or something better, instead of buying a cheap controller that is less stable. Another upgrade was to lengthen the machine from 60 cm to 100 cm. That meant waiting for new rails and ball screws to pop up on Ebay. I sold the old parts for what I bought them for, so it wasn't a big loss.

I got the bearings, but I ordered the wrong size. For some reason the shafts on these winches are 1/2 diameter, while everything else is metric. I didn't couble check before ordering, and ordered 13 mm bearings. Should have ordered 1/2. I'll have to wait for new bearings or figure something out with the bearings I have.

I'm gonna try something that probably won't work. I will make the second stage spur from delrin as well. But it'll be almost 10 mm thick as opposed to the 4 mm thick steel gear. It wil also have one extra tooth, to tighten up the gear mesh.

EDIT: Or not. I wish I knew what kind of material the stock gears are made from. A delrin gear is probably only half as strong as mild steel 1/5 the thickness. Not sure I want to waste that much delrin on an experiment.

Nice work milling the gears.

Do you find you power supply's noisy? (I see you use two for the motors)
I only use one and the small fan makes hell of a noise.

I ordered a Belkin 7 port usb hub, worked like a charm

I use the same type of PSU in my CNC-router and it's a little noisy, yes. The fans in the sim have never started so far. Maybe they will once I enclose them, but I will make ventilation holes over the PSUs.

Video with the new acetal gears and lights on. I'm running full duty cycle on both axis here, but reduced acceleration on pitch, or else it 's too violent.

http://youtu.be/vVI6H6mGsY4

It sounds noisy, because the camera adjusts its volume to whatever it's hearing, but it's a lot better than before. I can drive without ear defenders now without the noise bothering me. The engine sound you hear is from the speakers downstairs. I've got ear plugs on. The roll motor is making more noise, for some reason. It's always been like that, but I hoped it would go away when I got rid of the steel spur. I think the gear shaft is poorly hobbed or something. Maybe I'll make a pinion and a smaller acetal spur for the first stage, since I don't need as much torque there as pitch. That way both gears will be perfectly meshing.

In addition to the new gears I installed spacers inside the winch frame to keep the bearings firmly in place, because they will flex the steel sheet metal the winch is made from and cuase some movement. I've managed to reduce the backlash a little this way.

I received the switch/connector thingy today, and am routing out the top cover for the electronics box now, and will bend it at work on monday. Sheet shearing and bending is just about the only things I can't do in my shop. When the top cover is installed, my sim will be just about finished.

You sim is really nice. Fantastic work :clap:
I love how its floating around.

The psu's. The one i use should only use the fan when it needs to, however its always on max, even when the output is 0A, could be some broken component. I need to hack it,

Thanks. The PSU in my router turns itself on and off periodically, and it's pretty noisy, but the sim PSUs are just running too cool.

I just got motionsickness in the sim. I spun hard in the Radical just before the downhill in Lime Rock, and it damn near made me puke.

The cover for the electronics box turned out really nice. It took almost an hour to cut because of all the little ventilation holes. The switch assembly fits perfectly in the hole, so It's going to look really nice when I install it on monday.

I feel like making a cyclic stick for helicopter simulation now.

Thats more like it! A sim that does have after effects! :rofl:
Mine gives me a sore back after 30 mins of abuse!
As for noise, use headphones or turn the volume up!

I played with X-Plane and did a lot of PID experimentation tonight. X-Plane 9 with turbulence = motion sickness.

I found that I need different PID configurations when flying compared to racing. Is this normal? The movements are very different, and the forces simulated are a little different, so it might make sense. To achieve smooth movement in X-plane I had to raise the values to higher numbers, for example p1,56 / i0,78 / d12,5 while racing seems to work best with p0,5 / i0 / d0. Changing the derivative or integral error compensations result in jerkiness during racing. The Proportional setting changes the rate at which it tries to reach the new position, which is logical. I have to experiment a lot more. Racing requires a lot of fast up, hold for a little, and drop back down to center, while flying needs slower and more gradual movement, and a slow return to center after the motion is complete. That's probably why racing works fine with just P in my centrally stable sim. The increasing force required to move it to either end dampens the servo.

This is useful: http://igor.chudov.com/manuals/Servo-Tu ... -a-PhD.pdf

At one point I was testing in iRacing and was turning all the PID-values back down after playing X-plane, and I thought it would never get smooth. Then the car skipped (Radical SR8) and the simsimply jerked in sync with the car, and I realized that this car isn't supposed to be smooth.


BTW. After an hour of intense testing with severe movement the sim had moved 25 cm backwards across the room.

ha ha ha I love this line u beter get yourself tied down or drop an anchor. :lol:

The roll axis stopped responding now. The motor does not run. For a while the roll axis responded when I moved the pitch axis in the pololu app, which is just weird. It's completely dead now, though, with no errors. I tried resetting it by upgrading the firmware, but no response. Maybe it's the noisy motor that died, but the odd coupling behaviour indicates a damaged board, or something. Both heatsinks are cool. Changing USB port didn't help. Guess I need to order a new one.

It's just a faulty cable. The reason it moved when the pitch moved was that the cable moves a little when the pitch servo moves.

BTW, the plastic gears are not showing any signs of wear.

I fixed the broken wire now. It had rubbed against a gear earlier, and I thought I had caught it before anything was damaged, but before I test, I'm gonna replace the noisy roll motor and see if it makes any difference. I got another winch today, and luckilly it had the same kind of motor that the pitch servo has. The old roll servo motor has a little different looking motor, with slightly different shaft diameter, play in the shaft, and visibly different gear teeth. The new motor is the same type as the one II have in the more quiet pitch servo.

Awesome! That did the trick. The new motor is quiet like the pitch servo.

It behaves like the pitch servo as well, meaning the PID values for the old motor caused it to oscilate. I like that!

You work fast as hell!! really fun to follow your thread. Do you think you could do a video of the linear bearing and winch assembly while running? i would like to understand a little bit better how you push and pull with the winch. Feel free to refuse if you want to keep it secret!

Btw, i'm shopping for cnc parts now. I don't know what i will do with this machine but man i want one! I have been reading on cnczone for 6 months now...

Yeah I really want my own CNC milling and lathe machine too, It would help a great deal with making my own custom parts.
However I need it for steel which is a different ball game when making your own CNC from what I gather.
tahustvedt I love your work dude, simply awesome, as been said before the speed you work at and the quality of the result you get are A+.
Keep up the good work, whats your day job btw are you an engineer of sort?

I'll try to shoot a video of the mehcanics later on. A friend of mine is coming over to try it later today.

I'm a Westland Lynx helicopter technician in the norwegian air force.