final year project: 2DOF seat mover motion rig :)

@noorbeast , the problem is, that we cant mount it directly to the seat, since it is made of glass fiber and has it's mounting holes on the sides.

I will definitely try to convince them. But luck is on our side, since we didn't declare what exactly we need to do, just "programming the cylinders"

@IJOJOI , I am not sure what sort of uni joint you are using, but if I use a cut down tailshaft, the actual uni is about 120mm from the bottom mounting point to the centre point of the uni joint. I think. That allows for steel plate, bad cutting of the shaft.
something like this maybe. Mind you I show the end that bolts to the diff as the shortest end.

with the seat, just use 16mm MDF with a 25mm steel box frame under it around the edges to support it. Screw the MDF to the frame, uni joint bolts to that, seat screws down on top of MDF.
something like this (desk racer example)



Where are you planning to place the motors?

@IJOJOI
heres a bit of info between seat mover and full frame.
Heres what I came up with, didnt record lap times. No frame made made me faster or slower, so times were about the same.


Comparisons between simulators. Other people will of course differ with this comparison, so please add your thoughts.


First things to consider, angle of actual swing of the frames and the profile written. Also, its a brain trick.

If you want a big swinging frame, go hard, the biggest swing I have had is 14 deg total, but others have frames up to 25 deg. And thats for race, not just flight.

Both frames use same motors and JRK control boards


Seat mover with shoulder mounted motors.

Generally, a seat mover can give more precise motion detail as it has less over all weight to move than a full frame. However, too much movement can make it hard to hang onto the wheel or mash the juice pedal. And yes, the wheel and pedals are stationary, so proper placement to allow you being pulled away and pushed around has to be taken into consideration. But as said, it does give you the feeling of being moved around in a seat in a vehicle, even with a race seat to hold you in more. You tend to shift your body around to compensate for movement and also what your brain thinks you are moving like. You can still feel pitch and roll of track, but maybe a bit less as legs are still.

Some SCN seat movers on videos have HEAPS of throw. It might look like fun, but can be too much and eventually make it tiring to drive the game.

As mine is DIY and has 70mm travel of motor lever and at 600mm from the pivot , total angle is 6.5 degrees. Not much, but then again, too much may make it too hard. Other people will of course differ with this comparison.

I had a seat mover of 12.5 degrees at one stage, so with a good profile, it was nice, but a harsh profile and WHOA! Fun but hard to hang on.


Full frame with motors mounted near feet

Full frames allow you , wheel and pedals to move with you. You dont really get sensation of being pulled, pushed around from pedals and wheels. Obviously not as much as a seat mover, but still there. You tend to feel a bit more of the motion of roll and pitch , when your whole body is getting moved around, I find.

Seat mover can lose this a bit, but not really much.

Motors mounted at feet on the frame in question, may take away some of the finer vibration and motion that shoulder mount gives, but then again, shoulder mounting motors would return that finer detail due to higher leveage point. It may lessen a bit due to the fact that a full frame requires a bit more power to move. But hey, just change the profile and increase the motor power a bit more.

Although, I must say, once again, a good profile can give the same sensation in motion, be it from a different spot. Feet or knees instead of shoulders.

Full frame is about 8 deg total swing. May not sound like much considering 4 deg from centre, but again, throw a decent profile in it and you feel like you are moving a lot more.


Summary

After a while I get the same sort of feeling from both my frames, even though they are different in design.

In your choice of motion sim build, It will come down to watching videos of other frames, opportunity to play on sims when they are around to do so. Taking a look at pics, seeing what takes your fancy. Heck, even a seat mover can be converted to full frame later, add the extra bit, move pivot, and off you go. 2 seat movers I have sold, the owners have since converted them to full frames, their choice of course. They enjoy both frames they tell me.

I have played on dbox, and scn simulators and the motion is set tame. Although others whom have such rigs wind it up and get great results. Mind you, I dont have that sort of money to get one.

I have been through 14 different 2DOF designs, starting with joyrider design with about 9-10 deg total swing with screen on it. Good fun, but I found it a bit difficult to focus on a screen moving with you. But thats just me.

I had 2 hire sims based on the Desk Racer for a while and over 100 players though they were immersive.

8 professional drivers have played on those simulators as well, and they admit, its not real, but the immersion of being in game is.

Then I moved onto development of more compact designs, with motors under rear, at knees, out the side, shoulder mount, at feet. Still 2DOF. Screen static.

So thats how I go here. Each frame design is a new learn to drive experience I find. Nothing makes me go faster I think. I am slow regardless.

I may have missed something and please add your thoughts as well. Its always good to compare notes.

OMG, oral diarrhoea? Or weed?

pardon @value1 , what do you mean? Ive posted that comparison plenty of times before in other threads......

I mean it friendly your contributions are very welcome and helpful!

copy

@bsft
Very helpful post mate! really appreciate it!

So we are in the middle of redesigning our "simulator" an a few questions arose.

1) How powerful are these motors? In your design, they have to apply a lot of torque, since the distance between the applied force and the U-joint is very small.

2) If I'd keep the configuration form before and use the long levers, is there any disadvantage?
They may be under a lot of stress, if the peaktorque is applied, but this is very hard to calculate, since it can switch from positive into negative torque. I may have to consider a higher safety factor...

3) Just out of curiosity Why do you place the levers infront of the seat in your construction?
It looks nice I have to admit, but we'd have placed them in the back. Is there any particular reason for that.

Other than that, very very nice build mate. Looks really professional!
(apart from the lonely fan (joke)

Best regards!
Johannes

Hello @IJOJOI , I have used those motors across several designs for about 3 years now. Having the uni joint as close as possible reduces overall mass of the frame when it leans from what I understand. I just followed what works, and have not deviated.
The motors are good, they are 12v 200 watt and under stall power, they are more like a 550 watt motor.
Depending on the planned setup of the frame, placement of motors, design, max weight of driver, etc, you could use 25:1 ration or 50:1/60:1 ratio boxes.
With my design, which one?
With lever length, @noorbeast FAQ links about a 65mm CTC lever with JRKS, producing about 500mm per second actually, (Ive spoken over the phone to the person whom actually got that linear speed), however, a lever that long is not needed. It will depend on design of the frame.
with a safety factor, draw up your latest design and I can advise , Ive only been through about 14 design changes and each was an individual build. The 2 pictureed used those motors with 25:1 ratio boxes and 40 mm CTC levers.
With levers at front, I take it you mean the desk racer, max realistic weigh of driver 115kg.

the idea there was to make a compact seat mover, of which it did work out. about the same floor area as an office chair, 600 x 600mm.
As for motors at the back, I did that in a shoulder mount seat mover as well a while ago

However, for me, this was a larger frame, (800 x 900mm from memory) but it could move a heavier driver, like 140kg without a problem
Both use 40mm CTC levers for torque reasons. A longer lever will work mostly for speed, but you are trading off speed for torque. Saying that, it will depend on design. The 65mm CTC lever setup is only using about 80 deg total swing angle, but because its shoulder mount at rear and the angle of the motor connecting rods is near 30 deg, not 15 deg like mine, It has excellent setup for speed but in a larger frame.
Again back to full frames, Ive been through a lot of designs to test real life application.
Did I miss anything?
Dave.

just to add to this my system uses a rubber bit in stead of a UJ so it flexes in any direction seems ok to me too.
this is the standard way frex do it.

hope this is help too, worth saying tho for testing if easyer to fit and try.

If you have lateral twist, use a drag link to stop it

yes its got two drag links aswell i was wondering if one the rubber way puts more strain on the actuators tbh, as its compressing the rubber so will be using up force to qish it i guess. where as the UJ would not as its free moving.

Dunno really, good point though.

So a little update here
We will order some wiper motors it seems, as there is no other possibility.

Furthermore, I am currently half way into reworking the seat-assebly, so that I get the u-joint closer to the seat.
I will try to get to a reasonable result and show you some renders

Best regards

Ummm..why is there no other possibility instead of wipers?
And if you do go wipers as a start, thats fine, but earth isolate the case. Probably @noorbeast has a FAQ link for this.

@bsft We have to make a compromise.... I unfortunately can't find ANY shop that offers these motors here in europe.
It's a pitty really. I don't get it.

This is such an exhausting thing really.
I just dont get why bureaucracy is so annoying...

Best regards.