Suggestions for D-Box Type Home Theater Simulator

Wow, thank you for sharing. The video of that sim is really amazing. I am a bit concerned about the noise though. Anything I could do to quiet it a bit? Of course, winch motors! I should have thought of that myself. Man, that example is cheap. I like it. The board is cheap too! Great info!

Thanks again.

Mike

Wow, this is some serious stuff. I definitely asked in the right forum. Do you happen to have a video showing this design in action? Is the noise reduced over a winch motor design?

Mike

i dont have a video.
yes les noise.
gr.Ad

Thank you again for sharing your design. I may have to get it translated into English if I build this since I only speak one language proficiently. My compliments on your English by the way.

Too bad you don't have a video. I would love to see this bad boy in action! How many of these did you build? What was the application? Did it perform to your expectation?

What are the sources of noise? Bearings? Ballscrews? Motor itself? Drive mechanism (belt/chain/gear)? What can be done to quiet the mechanism as much as possible? Since the application is for home theater, I would like it as quiet as possible.

By the way, do you recommend belt, chain or gear driven. What are the advantages of one over the other? What about modifying the design to make it direct-drive?

So if my calculations are correct, each one of these could handle approximately 220 lbs right? So 3 could handle 660 lbs. What would I have to do to to increase their weight handling so I could use only 3 actuators? Stronger motor?

Mike

Winch motors have metal straight cut gears I believe, so they are noisy all over. They are designed for pulling a car out of a ditch and not really for simulator use. You could put a sound insulated box over them, that may reduce noise a bit. There is not much else you can do for noise reduction.

Or just turn up the volume......

Yeah, that is what I figured. Winch motors are cheap but I think I like the pre-built servo idea better and that should quiet things down a bit. However, even when using the pre-built servos, I want to build this thing as quiet as possible.

Hi
Ballscrews are bearings also
To be precice ,all the parts make noise but you only hear them with sound system off.(FD401 uses balscrews and servo to)
I recoment belt/direct driven ,most sillent and efficient
3 actuators needs a stronger design
I dont think you gone save money with it ,and the sabertooth/roboclaw drivers are dual channel also.
Whe use the same concept in industrial cloth printing machines for years.
regards Ad

Cool, then I will go with 4 actuators. That will get me to 880 lbs which is probably adequate but just shy of my 1,000 lb goal. I may be able to make some tweaks to compensate for that.

Should I be looking at regular ballscrews or freewheeling ballscrews?

Mike

Edit: Nevermind. I see the rpm is too high for freewheeling ballscrews.

adgun, I read through that application engineering link you provided. Fascinating stuff...

I am having a little trouble with a couple of calculations. In particular, torque is causing me some trouble. Let's say for the sake of argument my load is 1,200 lbs. (I read that ballscrews are 80% efficient when backdriving. Do I need to compensate for that in my load?)

I am thinking of using a 5/8 x .200 ballscrew thread. The drive torque ratio of that thread is .035.

So, a 1,200 lb load x .035 torque ratio = 42 inch per lb right? So looking at the motors you recommended I see that continuous stall torque is only 10.6 lb-in. so I don't have enough torque right? I need to choose a different motor/thread? Something doesn't sound right about this so I think I have mis-calculated.

Mike

Oops, I think I know what the problem is. I was trying to calculate the total torque needed on just one actuator but since I will have 4, I should have divided that by 4 right? So...

1,200 lbs of total weight / 4 = 300 lbs. per actuator (I know this is simplified because we don't know the weight distribution but it should be close enough).

300 lb load x .035 torque ratio = 10.5 lb-in and the motor you suggested has 10.6 lb-in continuous stall torque so I should be good right?

Mike

Hi
Forward and backdrive are allmost the same,backdrive is less efficient but create more force.
I advice a bigger screw it increases lifespan.
About stronger motors ,i,ve got one the mb100 fe 502 makes 500mm/sec possible with 1610 screw.
I dont know the price,they asked 115,00 euro for there mb80 fg502
Ad

Are you talking about changing the diameter of the screw? How large would you recommend? Is 1 large enough? Is there any downside (other than cost) of going with a monster screw? Do I lose anything? Do I want the regular or heavy duty nut?

Mike

1 wouldn't still be too thick,but I think most screws are metric in size so the closest to 1 would be 25mm, I might post a picture or two of my 32mm screw and nut which I don't consider to be too thick for the purpose. Thicker screw adds a little bit more moment of inertia to the system but the effect is miniscule at the best. Also remember that the lower bearing has to take all the forces and with a thicker screw there becomes available better bearings that can handle the load. You would have to look hard to find small bearings with suitable load capacity.

With my 32mm outer diameter of the screw best option to use would be 25mm inner diameter bearing, but I plan to make metal sleeve that get tig welded to the screw and tarnsfers forces to the inner race of 30mm inner diameter bearing. 30mm is the diameter of the screw thread valley so otherwise there would be insufficien amount of metal in the screw to transfer the forces.

hi
I made those drawings for the mb80fg502 motor,with 3nm peak torque
The 82bds173-208 motor got 8 nm of peak torque,this is pushing an 1605 screw to his limits (including under bearing)
It,s better to create a safety marge
regards Ad

OK, you guys have convinced me. I will go with the largest screw and nut combination I can find that has the right lead. I would be very interested in seeing your 32mm screw and nut setup.

So you are in the process of building one of these now? I am eager to learn anything I can from your experience.

Mike

1605 and 1610 are both 16mm diameter right? That is only .63 The only difference between the two would be the lead right? So if I used a 1 (or 25mm), that nearly twice as beefy as either of these. Given the relatively small amount of weight I am talking about moving, 1 seems way overkill for my application no? As long as there is no downside (other than cost), I'll do it anyway. I just want to understand the engineering involved.

Thanks for the schooling.

Mike

Hi Mike
About metric ballscrew sizes ,youre right first two =size last two are lead.
Using a bigger screw gives :avantage=lifetime and safety
disavantage =costs and mass interia(more mass makes it react a fuw nanoseconds slower)
Normaly they dont push the screws to his limmits for safety and lifetime, they use 30/40% from there max,normal in industry.
I can,t get a file so small for posting ,so you can see
i try with pm
This way it,s build to last.
For the parts look @ www.slidesandballscrews.com
regards Ad

PM is working file send.
Ad

@ Jyrki
www.slidesandballscrews.com have planetarygears now.