theorical question about 3dof motors

[ferslash]

In this days many projects has arise using 3dof, i saw them and they sams to be grate! all of them use big electric motors since the motors has to "carry" all the weight of the sim platform and the drivers weight...

on the other hand some months ago a guy published here that he made a 2dof sim, using 4 motor wipers, the guy never replayed questions but some of the community members agreed that this guy used the wiper in couples so they "share" the job... http://x-sim.de/forum/viewtopic.php?f=37&t=672

the questions are:

1. is it posible to achieve a 3dof using wipers Sharing the job.. (lets say three pairs of wipers, 6 wipers in total)
(the kind of sim i mean is this one: http://x-sim.de/forum/viewtopic.php?t=911

2. how much force does the motors needs to achieve 3dof and how much force does a wiper has?

best regards guys

fer

[ferslash]

any one??

[prilad]

2. how much force does the motors needs to achieve 3dof and how much force does a wiper has?

For 3 dof system with chair+gamer summ weight = 150 kg we have at least 50 kg on each axis
let the length of the lever on the motor shaft is 50 mm (0.05 m). It mean that MINIMUM shaft torque mast be 50kg * 9.8 m/s (=490 N) * 0.05 = 24.5 N*m

At the other side torgue of DC motors is approximately 9,554* P / n (where P = power (W) and n = rotational speed (rpm)

As I know wiper's power is approximately 50W... And with worm reductor (performance = 0.7) it has speed 60rpm (approximately)... And it torque = 50*9.554*0.7 / 60 = 5.5 N*m

So without central spring we need 4 wipers for each axis

regards,
ALE

[ferslash]

Prilard, you are the man!

That was kind of answer that i was needing, (i just didnt know what to ask) .... (and of course i dont know fisics )


so, if i only want to use two wipers per axis, i would have 6 wipers, given the calculations you made, if i need a total force of 73.5 Newtons*m to move the whole platform, and if i want to use only 6 wipers giving me a total of 33 N*m, i would have to use a central spring able to give me the force left...

so, if i use 6 wipers, 2 per axis, and a central spring capable of give 40.5 N*m could i make the platform move nicely ??? or i am totally wrong???

best regards and once again thanks fro the answer

fer

[prilad]

Prilard, you are the man!

That was kind of answer that i was needing, (i just didnt know what to ask) .... (and of course i dont know fisics )


so, if i only want to use two wipers per axis, i would have 6 wipers, given the calculations you made, if i need a total force of 73.5 Newtons*m to move the whole platform, and if i want to use only 6 wipers giving me a total of 33 N*m, i would have to use a central spring able to give me the force left...

so, if i use 6 wipers, 2 per axis, and a central spring capable of give 40.5 N*m could i make the platform move nicely ??? or i am totally wrong???

best regards and once again thanks fro the answer

fer

Hi, fer...

Yes, you are wrong.

in first - Spring force is measured in Newtons (N), but not in N*m.

in second - try calculate... all (platform+gamer) weight = 150kg and it load the motors levers (without spring) with force 150 kg * 9.8 m/s = 1470 N

One wiper with lever on the motor shaft = 50 mm (0.05 m) and with approximate torgue = 5.5 N*m can produce only 5.5 N*m / 0.05m = 110 N at the end of lever.

6 wipers can produce only 110*6 = 660 N... Therefore spring force must be at least 1470 - 660 = 810 N... But IMHO spring force must be more then 1000 N to reduce loads of motors...

Excuse me for many digits

Regard,
Ale

[ferslash]

prilard thanx for replaying that fast.

so... with 6 wipers and a spring able to deliver 1000 N, it is possible to move a 3dof?? theoriclly??

best regards my dear prilard..

by the way, what did you studied?? mechanical ingeniering? electromechanical? electronics?

fer

[prilad]

prilard thanx for replaying that fast.

so... with 6 wipers and a spring able to deliver 1000 N, it is possible to move a 3dof?? theoriclly??

best regards my dear prilard..

by the way, what did you studied?? mechanical ingeniering? electromechanical? electronics?

fer

Hi, fer... theoretically all is possible But there are a lot of problem for creating 3 dof with 6 wipers...

first of all - it is impossible to achieve a fully synchronous operation of two motors per pair... need to construct a special suspension arm... May be better to create 6-dof?

second of all (or may be first) - wipers is still very weak for this task... which will require a very laborious setting up of the spring force, which will depend even of the players weight...

What about my education - I am an electronics engineer since 1985 (yes - I'm an old man ), and a self-taught programmer. But physics and mathematics "are in me" since high school - Russian education system...

Regards,
Ale

[ferslash]

we better dont talk about ages, i am 33 i was born in 1979 jajajaj... anyway we bouth are born in the last century. about education... i got a degree in management... so fisics and electronics are not my stuff (by i get shocked by this site)

and regarding the motor set up, it is a shame i love wipers, because they are almost free i guess wipers are dummed to be used only in 2dof



(i saw another post where you are talking to sir no name,) did i understood well?? are you rusian guys developing a new sim software??

best regards

fer

[prilad]

and regarding the motor set up, it is a shame i love wipers, because they are almost free i guess wipers are dummed to be used only in 2dof

Yes, I'm also going to build a 3 DOF on wipers, but then a little calculate and realized that will not work ... alas

(i saw another post where you are talking to sir no name,) did i understood well?? are you rusian guys developing a new sim software??

not software yet but firmware... and setup GUI here

http://x-sim.de/forum/viewtopic.php?f=39&t=237
http://x-sim.de/forum/viewtopic.php?f=39&t=695

regards,
ALE

[ferslash]

oh that one, i have seen it a lot of times, i have even got an arduino because of that post :D:D i havent beggin but i got the arduino jajajaj

i have never understood what you guys mean with a gui.. for what? for the thanos firmware?? what is that for? to do the calibrations of the motors?

and...


just by the way, and considering that you have already ordered your big motors...

do you think that the "6"dof wiper sim (considering that 6 would be easier than 3 for the syncronization) could be made using 6 wiper with a lever...

like this? http://x-sim.de/forum/viewtopic.php?t=766


best regards

fer