Needing some insight to start design

First of all I would like to thank everyone on this forum who has provided all of the info I've learned thus far.

So I've got a dilemma. I am interested in building a 2 DOF sim, which I feel would be plenty enough fun, and I know I'm NOT going to be able to build the most amazing set up ever and there will be sacrifices. But one thing I'm disinclined to be moved from is I want a full 45 degree tilt in all directions... on limited amperage (15/standard in the US). I see many people on here with insane amperages supporting their systems, and I don't have the resources to replace the breaker and run all new wiring through my wall to support the change. So unless I'm missing something where I can magically procure more than 15 amps out of thin air, thats what I'm stuck with (for now, I may be moving in the near future so having a highly upgradeable design is mega super bonus points). I have not seen many, if at all, 2dof DIY sims that have that range due to the fact that the axes' are well below the seat and of course the farther over one leans, the more power the motor's going to need to compensate. So my idea is design a rig that somehow bring the center of my mass closer to the axes (vertically) so that my motors don't need to do as much work. Speed of the motors is also a concern of course. I don't need break neck snapping back and forth, but its still gotta be fun! I saw a build on here that looked very professional (dont remember who posted, but it was all in french if that helps) and they brought the axes up to belly height while seated in the chair by building a frame around the seat that remained static with the seat, and then built a larger frame around that to support the smaller frame. I do like this idea, and I think if i were to do something similar by suspending the inner frame (with the seat) by steel cables (one cable per axis) and strung each from one end of the frame straight up to a pulley and over to another pulley horizantally on the opposite side of the frame through another pulley and then back down to the smaller frame again, it would be suspended without using energy but it would still be able to shift itself in any direction only by overcoming its inertia. If so, I may be able to use a motor that doesn't draw that much power and get my 45 degrees (or a little more, why not) AND I'll be able to immensely upgrade it down the road to a 3 or even 4 dof with a lot more POWAAA. But thats another story. Anyway, hopefully I'm actually going somewhere with this and didn't just waste everybody's time. I understand that describing the design is very vague, so if need be I can try to draft something up a little more visual on sketchup (poorly, albeit). Any and all comments/questions/insight/criticism and/or downright-berating is welcome from anyone.

Thank you!
Jonathan

Hi @simyoulater

First of all, 15 amps AC at the outlet in your wall is not the same as the DC amps you'll be seeing in your build. I am not an expert on how that works out but for instance my 200 amp mig welder has no problem running full tilt on a 15A outlet in my shop.

As far as the 45 degrees of movement goes I'll let the far more experienced members of this forum chime in. Go big or go home!

@kopper

ahhhhhhhh that explains sooo much... never even considered that, thank you. I'm kind of embarrassed considering I work for an electrical distributor. I will have to do my homework on those conversions.

thanks again!

@noorbeast

OH yes, I've completely neglected that entire aspect.

Honestly, a little bit of everything would be fun, but (vehicle) racing is absolutely my focus. I have a g27 and I weigh about 200 lbs (though I want a little leeway with the weight ... just in case ). And although I think I understand what you mean by "wallowy" I'm not sure I fully understand it contextually due to my lack of experience in the field.

If you are going for 45 degree's of movement, I assume you mean your Sim will lean 45 degree to the left right?

You really don't need that much movement to trick the mind, plus if you are leaning 45 degree to the left and go the opposite way, the sim has to travel through 90 degrees. It would take a very long time to catch up and if you want to match the lean to the screen action you would get thrown around like a rag doll.

I'm new to the sim building as well, and I found the best thing was to post a rough design and let people critique it for you. Everyone on here is happy to assist in a positive way to help you achieve your goal.

That is very insightful, thank you both. I liked the 45 degrees, not for every little turn, but only when there is high lateral g's. My thoughts were that in a real race car, it is very common to hit 1 lateral G (if not much more depending on vehicle) on a track and 45 degrees on a stationary machine is only half of that. Again, due to my inexperience, I wouldn't understand how impractical it is on a sim. So really for a 2dof of any sort, there's no real reason to deviate from the standard 2 wiper motors shifting a seat that's being held from a support underneath with a uni joint?

hi simyoulater, if you want to realize 45 degrees you have to think about the joyrider. A seat mover won't be able to perform the 45 degrees in a satisfying way and especially not by using wiper motors.

Thank you all so much. This has saved me days of brain-ache and problem solving trying to do something that wouldn't even be practical if I managed to achieve it. This has opened my eyes to whole different line of thinking. I'm definitely going to look into the g seat to see if its financially permissible. Also - I liked the way silentchill had his rotation set up, not too much, not too little. Is this something I should look into doing as a beginner, or should I hold out and just worry about the other 2 dofs for now?

The GS-4 and seat mover works really well together. You get a really convincing sensation of G-Forces.

I agree with the others that a good simulator tricks the mind, with the movement of the seat and the pressure from the GS-4 then you feel enough of the movement and pressure that you would except so your mind fills in the gaps and makes it feel real.

A well built seatmover does away with the need for a gs-4 seat, once you have tuned the profile and the controllers correctly, you can achieve blistering and earth shaking speeds of more than 700mm/sec once there the slight movements you get from a gs-4 can be performed in m/s on the chairs motion, the chair might have rocked back but before your body has had time to drop back into the seat it back there in an instant , and you back gets thumped by the chair. ie surge movement and your brain is fooled into thinking you have just surged forwards. The immersion factors to key, a good profile setup and you tend to forget your on a motion rig, and find yourself tensing as the wall comes close and bracing the wheel as you hit the kerbs so not to swerve off coarse, feeling for the tires going and knowing how much angle to counter steer with , a world of fun.

I don't know if I agree with that. I think in any motion simulator the GS-4 would still be good. It adds to the pressure you feel. I know in my motion rig the GS-4 does make a big difference. Where it is good is not for quick movements, it is good for sustained G-forces around a corner, with a seat mover once your seat has tilted over in a corner you don't really feel that much, the GS-4 adds the pressure you would feel in that corner, it is also better and subtle changes in pressure.

As I have said before that seat mover is great for fast movements and the GS-4 fills in the gaps that the seat mover can't do.

I know what you mean about forgetting you are in a motion simulator and tensing for kerbs etc but also a lot of that comes down to the GS-4 as well. One of the biggest things that I remember from my real world racing days was the pain I would have in my ribs after a race. The GS-4 does this perfectly.

This is why F1 teams use pneumatic G-seats as well as motion, pressure is different to motion. So the GS-4 tricks your mind with pressure and the seat mover tricks your mind with motion. Then combine the two and they you have both sides of the brain fooled and you get total immersion.

If I was building one from scratch I probably wouldn't spend the extra on a GS-4, but if you already have a GS-4 then they work really well together and amplify the feeling you get from the overall motion experience. It is not massively different with the GS-4 but it does fill in the blanks and gives you a more complete feeling.

and a good back massage as @Rastus found out trying one on a dbox ride a while ago. Mind you, he is 87 and just fine with 2 DOF normal seat mover. GS4 not on his want list. Hes invested in decent pedals to give a better feeling when hes being tossed around.

very inspiring @eaorobbie ! reinforces all of my reasons for doing this in the first place.

Both the GS4 and doing motion seat at the same time is going to be out of budget for the time being anyway I cut it. I'm going to look into the extra speed, and then possibly rig up a makeshift pressure seat or something possibly way down the road.
whats a recommended motor value-wise for optimal snappines?

When using a nice fitting seat that doesn't have all the (girl) soft padding in it the feeling of pressure is all there, not sustained but you feel the seat dig at the ribs, pushs the thighs across but some use seat belts on tensioners to achieve this too, a lot cheaper way to do it.
I feel a nicely built seat mover with a traction loss without a girly soft seat is the ducks nuts for racing, 3 hrs on that and Im sore the next day, lol.

yes but you are completely mad. Dont tell @Rastus he has a "girly" seat on his ride. Hes liable to give a good swift kick.
@simyoulater , find a seat you like.
I use these, weighs about 9 kg
And they are padded well enough to be comfortable, but sturdy enough that you feel the vibrations.
As for motors, 12v 200 watt with 25:1 gearboxes are what I use on the desk racer with 40mm CTC lever.
And JRKS for control.
They will move 120kg person no problem

I got the same style seat, but it reclines, just because I drive quite laid back and these bucket seats put me in a position that feels a little unnatural to me - But that's a personal choice.
However, as @bsft said, if the seat is firm enough (and mine is) it's all good!

For Aussie members, This is the recliner I bought. (It's Still a bucket seat, so will fit a harness etc - just reclines)

http://www.soldsmart.com.au/Reclining-Racing-Car-Seat-Right-Side

(I just noticed it says GW: 20kg for my seat. They are not this heavy. I reckon 9-12kg tops )

And this is @bsft (currently out of stock)

http://search.soldsmart.com.au/search#?p=Q&srid=S10-AUSYDR01&lbc=soldsmart&ts=ajax&w=racing seat&uid=978138308&method=and&isort=score&view=grid&srt=24