3DOF - AC Motor Platform - 95% FINISHED - 020515

After increasing the frequency of the digital outputs for controlling the drives Forward or Back -t we do not risk despite the chronology of the Arduino code to order order sometimes for a very short time the 2 outputs for walking Front and Rear
How often do you work on these outputs?
How did you handle this possibility of interference?
The "Delay" is that loss of time while the frequency increase is intended to create a gain of execution time.
Have you chosen an integrated circuit solution to avoid potential interference?

Texte original
Après avoir augmenté la fréquence des sorties digitales servant à commander les variateurs en Avant ou en Arrière ne risque –t-on pas malgré la chronologie du code Arduino de commander de commander parfois durant un temps très bref les 2 sorties pour la marche Avant et Arrière
A quelle fréquence travaillez-vous sur ces sorties ?
Comment avez-vous géré cette possibilité d’interférence ?
Les « Delay » étant que des pertes de temps alors que l’augmentation de fréquence a pour but de créer un gain de temps d’exécution.
Avez-vous retenues une solution par circuit intégré pour éviter toute interférence possible ?

Hi again Tom! Your thread has stated 95% finished for a while now. It sounds like you have made some progress since then though. What percentage finished would you say your are now? And do you have any videos to show us of your beast in action?

Hello BlazinH,
Good to hear from you.
The project is 99.9% Complete.
As you know, I waited more than 6 months on initial electronics, then @speedy built them for me in no time.
We are having some issues with the electronics and trying to work out the testing to see where. Could be UNO, a faulty board, or VFD issues - BUT, we are making forward progress.
I've had the motors running so we're fine there.............it's just a communications problem............

Once complete, I'll up-date this topic and move forward.

Thanks for checking in friend.

Tom

Great to hear you're almost 100% now. Videos please when you get it all sorted buddy!

Will do...................
@speedy is almost as anxious as I am to get her finished...

Tom

Hey Tom,

Long time since I've heard from you...lol Quite a impressive looking rig you got there! Hope you get all the kinks worked out soon. I'd be going nuts right about now if I were you.

I'm glad I went with the scn5, 2 dof rig. I had that up and running in about 2 weeks with no experience in electronics. And that's what scared me the most, plus knowing it was going to cost me nearly $1400 to find out whether I could even do it!

Can't wait to see the video of your rig in motion. All the best, Mark

Hey Mark,
Good to hear from you again.
I went "NUTS" years ago. With the aging process, ??guess?? I'm that "Patience has Virtue"..

Yes, I am very excited about being finished.....................long, overdue, project.

Thanks, Tom

Hey Tom,

I'm a little mystified by that specially made coil spring. I didn't see any references for it purpose.

Thanks, Mark

Hi Mark,
The "spring" is an ASSIST Spring to help with heavy load of top platform and to give longevity to the motors/gearheads.
I had it custom made. Found only 1 manufacturer in US that would do me 1 spring with my special criteria (@speedy helped me with a spring calculator).
The spring was 300.00 for 1 and like 310.00 for 2 - so bought 2. I'm going to use the second one to build a "playground toy" for my young grand-kids.

Tom

Thanks Tom,

I read that you had it custom made in the earlier posts but couldn't figure out exactly what the spring was trying to do. Won't it hinder the movement also? Sounds like a real complicated formula's needed for that type of setup.....to get everything balance properly and then it's always changing depending on the operators weight.

Is there a proven model with the spring setup your following or is this the first prototype?

Thanks again, Mark

Hi Mark,
The "center spring" on a platform type sim is not new at all, and a proven part of many professionally sold sims.
In my initial research, I saw so many DIY platforms and these folks used "every kind of spring imaginable", and I am sure without any consideration with rebound rates, platform loaded rates,
coil diameter, wire diameter used, etc. etc. etc. etc.,...................

I found a very professional spring calculator on-line that took about 10 pertinent items into consideration, and would then calculate the exact type of material that should be used, number of coils,
height, and so on. With the help of @speedy, we came up with exactly what I needed. (I already had weights with load of top platform), and my 1hp motors and gearheads calculated that they could "lift a
Volkswagen).

I contacted at least twenty coil spring manufacturer's here in US - and "all but one" was not interested in making me a one-off spring.......they could easily do it, BUT, wanted to deal with orders
of 100+ springs. One manufacturer agreed to do it after I explained it was for my grand-sons......(kind of a little white lie, but some truth to it).

It IS a prototype - and with the strength of my motors/gearheads, there is no problem in "dampening" movement.

Tom

Thanks Tom,

Super.....it sounds like a lot of thought and figuring went into just that one thing alone.

Can't wait to see it in motion, Mark

Mark,
In all actuality, several days and many hours went into the spring configuration. Didn't want to make any mistakes as it does play a major role if "too weak / or / too strong".....just changes
everything.

Tom,

Ya...that was my main concern and then to be able to make it work under so many different conditions. Is it figured out to be able to run from let say no one on it to let say someone who weighs 250lbs? Or is there a min., max. weight limit? Did you look into any adjustable spring options?

My platform is designed, in a loaded state, for the top platform to weigh in at 450#.
If my grandsons' are in it, we are looking at a loaded rate of 350#......IF the profiles are too radical for my boys, then I will have to tailor a profile just for them
The spring is designed for 400 - 500 lbs.

Yes, I looked at so many springs that I frankly hate them now.........shock absorbers, tube shocks, and on and on and on..................so, I was lucky enough to find the spring calculator and with the
help of @speedy, came up with what I needed............then lucky enough to find only one manufacturer to make it for me...........SO, in summary, I don't have to say "Boy, I sure hope it works"........
because taking a 235# platform top off to change a spring - WELL, at this point - AIN'T going to happen.

Thanks again Tom for all your time and patients with all my questions. Can't wait to see that bad boy running! Mark

Mark,
THANKS for asking. My pleasure!!!

Blessings,
Tom

(as requested I've started a new project for this - "Compact 3DOF Motion Platform")

Hi Tom
Apologies for jumping in on your thread but after a 12 month break due to personal reasons I'm trying to get myself interested in sim racing again and once again thinking of adding motion to my Race-Star cockpit. I'm hopeful that I can gain some useful information from yourself and some of the well experienced members that have helped here.

I'm considering a 3DOF motion platform using AC motors and in my searches have come across a reasonably compact design from MotionSystems in Poland -

(version 1)



(version 2.0)



You'll see that there's no central cylinder or spring.

In the first video, which looks to use motor/gearbox units along the lines of those linked to below, I can't see the Inverters, there is a box in the background but this doesn't look big enough to be holding them. Also what's the small box with the cable coming out situated on the rear of the motors (just interested as to what this might be). In the second video the Inverters look to be attached to the motors.

This particular model (PS-3TM-750) looks to have been superseded but this one would be easier to make than their new, very expensive models.

To keep the costs down I've come across these motors, gearboxes and Inverters. Can anyone confirm whether or not these would be Ok ?

Motor - https://www.inverterdrive.com/group/Motors-AC/TECA2-802-4-B34-IE2-750W-80-frame-4-pole-AC-Motor/
Gearbox (35rpm output) - https://www.inverterdrive.com/group/Gearboxes/TEC-FCNDK63-35RPM-right-angled-Gearbox-750W/
Inverter - Mitsubishi D720 https://www.inverterdrive.com/group/AC-Inverter-Drives-230V/Mitsubishi-FR-D720S-042SC-EC/
- or TECO E510 https://www.inverterdrive.com/group/AC-Inverter-Drives-230V/Teco-E510-201-H1F/

Will these motors/gearbox units require any positional feedback sensor or encoder system ?

All help will be greatly appreciated, thanks

(as requested I've started a new project for this - "Compact 3DOF Motion Platform")

Hellllllllllllllllllllllllllllo Roadster2,
Long time no see or speak with you.
I hope you're doing much better with the passing of time.
PLEASE PM me when you have time.

From the beginnings, I've come a long way and have really expanded my knowledge in this particular field. I've had lots and lots of help, and without @speedy, I would not have survived this
motion platform...........

I will look more tomorrow when I'm rested and can assimilate better.

IF I were to build another platform, I would build the #1................it's doable, would be fairly easy to build and have control arms built, PLUS, no 300.00 US dollar "Spring".
I feel they may have used "encoders", which are very expensive for DIY'ers to purchase.

One thing I have found, and was lucky enough to get right (again, pure luck when it was all said and done), is to match your motors speed / and to match your gearhead to your motor.
Not ALL gearheads are created equal. Mine are 60:1, 1800 rpm motor, which gives my crankarms 30 rpm, but my output torque is 113 FT. LBS......
You're showing 40:1 with a 1440 rpm motor which equals 36 rpm, but without doing nm to ft. lbs, you MAY be low in torque output.???? I'll have to look closer tomorrow.............plus what length
your crankarm will be all plays into overall torque output.

Let's talk more.
Blessings,

Tom

PS - There are "tons of folks here" that have forgotten more than I know that will surely help. Not many platform builders, but they sure know a lot that can help you.

Here guys you can find more informations about this build ... into these next threads :

- Questions - Help - 3DOF AC Platform IT Begins -
- Questions & Answers - 3 DOF AC Platform - 4th DOF - Is "this" Feasible???