SimHawk's motion simulator

Hello!

First of all a thank you to all the developers and the community for great SW and ideas. This website made me start my motion sim project!

My goal:
To build a pneumatic Frex style motion sim to use for mainly racing/rally.
This is going to be entertainment for grown up boys!

My background:
I am a family man with a wife and a four weeks old kid, so this may take som time to complete. I work as a HW/SW engineer.

Where am I?
I have read many DIY threads and have gathered lots of information. I just managed to get the X-sim SW work under Windows Vista. It worked after disabling UAC in Vista and logging in as an Administrator. I successfully drove LFS and configured profiler to see the target values for the sim changed while I drove. Nice!

With all the SW in place (thanks to you guys) I have started to look for the HW. I ordered the Velleman USB interface and I have found a local vendor for SMC pneumatic parts. I visited them today, but neither the shop or I knew what pneumatic parts to look for. I will send a mail to SMC-Norway to ask.

What I know is that I must have at least 2 5port/3way-middle closed valves (preferable four for 3 speed operation). Around 20ms response time. For the cylinder I am a little more unsure. Stroke around 100-150mm and what bore? How much force is needed? I have a 8 bar compressor already.

I want something like the SimForceGT:



Thats all for today, let the project begin! :razz:

Current project status (log):
* Frame finished
* Valves in place :top:
* All wired up and the simulator has made its first maiden moves!
* Struggeling with simulator overshoot and regulation
* Found out that I need some needle-check valves to regulate cylinder speed. :
* Here is a video of the first testing :
http://www.youtube.com/watch?v=1NgQwUUCoHc
* Installed needle valves and made the sim work better
* Project finished! Sim is working - time to drive!
* Pneumatics has the speed and the force but not the smoothness and precision. Unsure if pneumatic is the way to go, for those who have not started I would recommend checking out the electric wiper frex projects going on on this forum.
*Video of current sim:
http://www.youtube.com/watch?v=YrgLyWqzxUI

You've informed yourself quite well already! :gut:

All that you mentioned is right. You should use 150mm cylinders with a bore less than 50mm perhaps.

Dont know how much pressure you will need exaclty. But I assume round about 1-3bar. You need a choke for sure.

Have you red Ferrari_man's thread already? You have to attach the pots like Sirnoname mentioned.

ego

Yes, I've read ferrariman's thread. The pot's should be mounted on the cylinder axis rather than the simulator axis. I have a pressure regulator on my compressor so that allows me to run with the pressure I want.

BTW: thank you sirnoname for the UAC solution on Vista. Maybe it works with the suggested run as an admin as well. I'll try. Main thing is that I now know that it works under Vista.

Today I'll try to find out wich SMC pneumatic parts I should order. There is a jungle out there!! I do not want to spend more money than I need.

Anybody that uses SMC parts and can give me a suggestion for part numbers for valves and cylinders?

Hi, Simhawk

Since you are going on the pneumatics way, why don't you try to implement an idea we had recently and regards the use of a servo operated manual valves? This way you could use the electronics of my previous motion controller (Basic stamp2) to proportionally control the flow of air thru valves instead of just open-close them...

This way of control will allow precise positioning of the cockpit and smoth accelerated motion.

Thanos

I've ordered a 1/2 valve for testing already. I'll open an extra thread this evening ;D

Hmmm... interesting thought to use servo operated valve.
Today I visited a local store and laid my hands on a SMC cylinder and 5/3 valve, but I'am still in the planning phase so I did not buy them. The valve was pricey! Around 200 Euros pluss coils and connector. The cylinder was a SMC CP95 with 32mm bore and 150mm stroke.

For the servo solution have you any idea about what kind of servo is needed. A standard RC servo or maybe a high torque one. Maybe a servo operated valve will come out cheaper.

tronicgr, do you have a working controller board that is compatible with X-sim? And with PWM servo outputs? Do you use a self made pcb to put Basic Stamp onto?

BTW: Is everybody else going away from pneumatics? As I can see it is still some work to be done to find a cheap enough solution for an electric one. It would be nice though. It will be a little annoying for my neighbours when my compressor starts and stops late in the evening when the sim runs.

I'm not turnig my back to pneumatics in general.

But we'd need to invent some cheap DIY servo valves. The I/O valve system with pulsmode is not good enough for serious simulations.

Have you tried ebay for cylinders?

BTW, I'd propose you airbrush compressors instead.

Hi yobuddy,

Is it true? 5/3 valves for around 35 Euro! That is waaay less than 200 pluss. How do they work? Have you completed a 3 speed setup?

Hi SimHawk

I have a working controller based on Basic Stamp2 that operates servo like motor controllers like the HB-25. I use the parallax's basic stamp board of education to host the BS2 chip but I also designed a more simple PCB board for anyone would like to purchase only the BS2 chip and make it by himself.

Now I'm making the new AVR controller that already supports servos with ultrahigh speed! PWM driving of motors are yet to be implemented on my new avr controller. I'm in the programming/testing procedure for this right now.

So if you like to try the servo operated valve I can easily design and program a AVR to drive them (since its faster than the older interface with the BS2).

It will need a high torque servo for sure but we might come with other solutions. See the Ego's relative thread on pneumatics...


Regards,
Thanos

Hi Thanos! What do you mean with servos with ultrahigh speed? Is there any difference in the control from the standard 20ms cycle/1-2ms pulse modulation? Isn't the speed of the servo determined from the servo motor itself, not the control signal?

I have RC RX/TX and servos at home and could possibly buy a high torque servo and a manual valve to play around with.

The difference is that I update them in 5ms cycle periods. This makes them faster and more precise in positioning.

The servo max speed is indeed determined by the servo's motor, but the reaction time and its resolution in positioning can be improved if you send to it the pulse in smaller periods than 20ms. The only limitation is that below a certain value the period can influence the pulse and the servo itself can report wrong position pulses.

Thanos

OK, I see. What is the performance gain approximately?

You can see the difference in performance in this video:
http://www.youtube.com/watch?v=S5RaAWBxb08

In same cases they move almost instantly!!

Illustrating vid. Fast response on the servos - for sure. You got to have a lot of spare time BTW! :wink: Lucky for us if we can use it later. Keep up the good work.

No, I don't have more than a hour spare time everyday... I wish I had!!

So many things... so little time!

Your local distributor is not so local for me unfortunaltely. You live in USA? I'm in Norway. The prices so far has been off my budget, the cheaper ones has poor response times and airflow, but I keep looking.