What would be a good start?

[blackhawkrob]

Hey everybody,

I'm new to this forum, and it is exactly what i was looking for.

Now - i've had this idea to create a 3-piston race-simulator. I know i need 3 (rather strong) pistons, and something to control them.

If i have that, i'll be able to make the rest myself (seat, screen, frame, wheels, pedals, link to software etc.)

The problem is - i don't know where to start.

I want a 3 pistol simulator - two in the back, 1 in the front. Then i can use the front + both back ones for acceleration / deceleration, and the left and right one for the roll. Don't know if i'll add yaw as well.

Anyhow - i've just ordered my ARDuino, as i guess i'll need some microcontroller to control the pistons.

But, what would you advise me to use? Should i go with pneumatic pistons (air) ? Or hydraulic? Or just no pistons at all? If not the latter, how would i control them?

My guess is that i need a pump for the pressure of the hydraulic system, and 3 valves to control each piston and 1 general valves.

My question is - what kind of hardware am i looking for? Any names, brands, places to buy them?

If i can find that, and control them precisely... Then i guess i can start building

Best Regards,
Rob

[tronicgr]

Hi Rob,

There are better and more accurate ways making a 3DOF instead of air-pistons. Have you thought of AC motors?

Anyways, do you have a drawing of what you have in mind? How the actuators are going to be placed? Will be low Center Of Gravity, or top mounted platform?


Regards,
Thanos

[blackhawkrob]

Hi TronicGR,

There are? You mean those wiper-motors? I thought working with pistons would give a better effect. I don't have any real idea's yet, except for that fact that i want to make it look like this one; http://www.youtube.com/watch?v=dc0GxMk0kk4

Thats the reason i also thought pistons would be best. I imanged the platform lowering to 0%, then get in, and once you start it up it goes to 50% (halfway up), and from there i have all pistons to move 50% up and down. But you really think those motors are better?

I want to gather some information before i start drawing first.

Thanks for the quick response!

[tronicgr]

Hi Rob,

I wasn't talking about wiper DC motors... Or any other DC motors...

I was referring to AC motors! http://en.wikipedia.org/wiki/AC_motor

They have 5-10 times more torque than DC motors (given a good gearbox ratio) for less price tag!

For example lets compare a classic DC motor and a generic use AC motor:
A PM60LWS 24v DC 280W continuous 11.4 final rpm 100Nm, has torque 76lb-ft with price $760
While a MTR-1P5-3BD18 220V 1KW AC with WG-262-060-D gearhead (with 30rpm output ) has torque 370lb-ft and price $370

So faster and stronger...

You can make a similar motion system to the one in the following link but for 3 motors by adding a center support column...
http://motionsim.blogspot.com/2013/05/6dof-on-lfs-and-x-sim3-using-beta-6dof.html

Best Regards,
Thanos

[blackhawkrob]

Hi Thanos,

Ah, like that.. Well, as far as i can see this isn't realy that much G-Force that you can simulate, now is it? Wouldn't i get better (more extreme) results with an hydraulic system?

Why do you prefer AC Motors over an Hydraulic system?

Thanks in advantage!

Regards,
Rob

[tronicgr]

Hi,

I don't prefer Hydraulics for just one SERIOUS reason... They are very dangerous. They involve oil pressures from 600psi up to 6000psi, which if they leak it can cut you up really bad. Apart from the mess if it leaks...

(for comparison car tires have usually 30 psi pressure...)


Thanos

[futuresims]

Hi blackhawkrob,
For ideas like the link you have provided which is a forcedynamics style motion simulator,

See the work of Riton at this link,
viewtopic.php?f=37&t=610&hilit=riton

If you would like to build a 3DOF 24V DC motion base then see these two links,
This is a complete project from the beginning to the end with a complete cut list.
You can easily modify every parameter of this project.
You have complete calculations for every aspect of this project .
viewtopic.php?f=38&t=909
viewtopic.php?f=38&t=910

You can Choose AC motors and you can use Tronic's AMC128USB board

Thank you

[tronicgr]

The AMC1280USB is not only for AC motors... It can drive DC motor h-bridges as well, in PWM and Analog method (sabertooth)...

It even has option to connect a mini servo extension for model verification.

AMC1280USBv1.c_with_servo_extension.jpg (500.47 KiB) Viewed 6649 times

Best Regards,
Thanos

[viawave77]

Hi Thanos, this is my start, but when all plug in and power on I have this little moves of servos.
Do I miss something? the servo numbers on the lcd panel are moving, too
http://www.youtube.com/watch?v=-Ed_oixjYRY
Regards
Italo
Viawave77

[tronicgr]

Hi Italo,

I was going to email you about it but I'll write it here instead. You need external potentiometer attached on each servo, like you do for real life platform motors, to implement the position feedback. The servos now output speed and direction but positioning is not complete without feedback loop from the sensors.

As I said this allows to build the real size platform under scale.

If you wish to have the mini platform without extra position sensors attached and use their internal position sensors, I can add that function the next days but the result motion won't be so realistic as servos tend to move to the commanded position in full speed and stop abruptly.

Regards,
Thanos