Wickie´s 6DOF Sim

Hi Peter!

I've been following your (and chills) progress and just had to register to say thanks!

I'm in the process of sourcing all the bits in hope of building something that resembles your awesome rig

If at some point you happen to post the full BOM that would just be a cherry on top.

Thanks again!

HI @Will974
After increasing the Speed of the actuators, sometimes the 1800W PSU switched off. So I decided to use the batteries for simracing and use the PSU to Charge the batteries. But for use of the platform for flight it shoult be ok.

Wickie

Hi @Rad
I will make a BOM of the main Parts as soon as I have some more free time. Have you Seen the actuators from SilentChill? I Love his design mainly based on 3D Printed Parts! They are much easier to manufacture.
Wickie

Yes I have, I’ve been following both projects closely. You’re right regarding the 3D printed parts, I have a 3D printer so will most likely print as many parts myself. In the end it will probably a fusion of your overall design, including the enclosed actuators with SilentChills 3D printed bits.

-R

@PeterW are you using 1605 lead screws? I saw Silent Chill was running his actuators around 5000rpm, what speed are you running yours at?

Thanks

Hi @MagicMunkyNuts
I also use 1605 Ballscrews. Currently I use 3000 rpm max. And this is f... fast. At this speed my platform starts to lift off the ground and a crash shouldnt feel any stronger.
I think when rating different actuators we allways should keep in mind that the acceleration time of different systems (e.g. those with brushed motors) can be quite different.
It would be interesting to compare the real speed of various simulators.
Wickie

Thanks for your answer peter. I spend actually a lot of time to configure my own upper base with my own geomtrie, and it was not easy to find the good configuration, but i finally find the solution. I will show you and all my work soon

The calculations I've been doing show that you can easily drive a 1610 ballscrew at ~3600rpm to get 500mm/s with a 40kg load per actuator, and with only a 1.2Nm BLDC outrunner!. For a while I was thinking that you could even get away with mini-ball screws since their strength is actually very high for what they are, but the mini ones are often more expensive than the much more common 1605/10.

Regardless, this BLDC outrunner w ODrive and ballscrew is proving to be a pretty awesome formula for super high performance, compact DIY linear actuators.

Edit: the theoretical values I got from my ball screw calculator say that a 1.25Nm motor and 1610 combo at 3600RPM will drive 48kg at 600mm/s, 1.5G max; and all of that includes a 2.5 Safety Factor!! That's mind boggling, especially since you say that the 3000rpm is a lot with 1605 ball screws. It makes budget-conscious, ultra compact true 6d0f feasible

Hi Peter,
I was going to build a simple 4 post system, but after reading through your thread i'm now sold and want to build a similar unit with a few changes . I have restarted re-reading the thread and have started taking notes. Can you please clarify the length of the ballscrew your using, in particular the actual travel area as most measure not effective travel are but instead overall length.

Hi Adrian
I use 600mm ballscrews, which seem to be a good length. Theoretically I could use aprox 480mm max., but currently I am using only aprox 370mm. Thats enough for this rig dimensions.
Now after some weeks of testing I can say that the overall dimensions of my rig seem to be perfect - so you could copy all dimensions.
Regarding the Odrives: Dont go this painful way! Maybe you could use the FlyPT solution? I saw people here in the forum that go this way. Or you modify the actuators to use the Thanos solution...
Wickie

Thanks for the Advice Peter !!
I was thinking using 700mm units as my local guy has them in stock and guarantees them to be 100% true at $40 each and $10 for each zero lash ball nut. Temptation is very high on the ODrives as I would require 3 control boards ( one for each pair ) and the D5065 should be more than enough to turn this into a seat belt required ride!

I have been following FlyPT's thread as well and find it that Thanos is trying way too hard to "sell" his product... and I will stop there as my mother always said if you have nothing nice to say, don't say anything at all.

Hi all!
The last days I spent with opimizing my settings in the absolut genious mover interface - especially the crash filters (thanks to @pmvcda !).
Now driving feels sometimes sooooo real.
Specially when driving up or down a hill or going fast through S curves you can feel so much the forces.....
Motion sickness is also completely gone and the Pimax motion compensation works really perfect!
Here are two driving videos.......dont laugh about my bad driving skills...





Wickie

And also I had time to finish my noise reduction-actuator-covers made from yoga mats.


And here you can see the fixture on the actuators with a "Klettverschluss"
The left actuator is ready and the right one is waiting for the cable cover...


And this is how the top end of the actuators look like. I added also a piece of a rubber hose as a damper..


Wickie

Ah... I forgot to tell you that I fixed my rig on the floor. This was necessary to avoid lifting off the ground and moving around (aprox. 250 kg !)


Drilling big holes in my livingroom floor......lol.

Wickie

It's moving around at 250kg ??

Nice sim , just some feedback which you can ignore if you want. IMO the movements did not look right and by looking at your sim/screen/steering movements, some of your forces seem to be backwards (sway) Ie. You turn right and the sim sways to the right - that's not right and others seem to have a mind of their own surge/pitch - were they work well and then sometimes not at all, or even backwards - maybe too much pitch? Anyway something to look at... have fun.

Likely 200kg + of inertia when in motion and it is siting on tiles.. yep its going to move. My old Stewart Platform use to run into walls until I mounted it to a big heavy rubber mat.

Hi
thats an interresting comment and I think you have a ton more experience than me! So this inspires me to make a new thread soon, discussing the correct movements of a motion sim.
You said: "You turn right and the sim sways to the right - that's not right..."
Like I told I am not an expert but I can explain my feeling .....
When I drive a fast right curve:
In a real car and due to inerta you got pressed to the left side of a seat.
To simulate this feeling, at the beginning of the curve, the platform has to move fast to the rigt side, so that you can feel the seat on your left. Because the movement is gone after maybe a second (due to the limited travel of the movements) you also have to add something more. In my feeling this is constant roll mixed against clockwise. With help of this both settings, I get the same feeling than in a real car. But thats only my current opinion...we will see


Regarding the your comment:"..and others seem to have a mind of their own surge/pitch": The tracks that I am driving in the Videos have some hill up and down parts. This is difficult to see on the screen. This Motion may leed to the conclusion that there is some "mind of their own".

Regarding my huge pitch Settings you are Right !....but it feels so cool when you get pressed into your seat when driving up a hill

So in conclusion I would like to say that I am not interested in justifying and saying what is right and wrong - quite the opposite. I want to find out what is optimal. And for this purpose I will gladly take a closer look at your comments and also test other movement settings - so thanks for your comments!

Wickie