What size motor to use?

Co Tang · Jan 21, 2015

Hi Guys!

I scan through the forum here and there and there is a LOT of information. I read about 3 hours last night and came up with a concept that will work for me. The only thing is the motor. In your experience I want to build a 3DOF mini-platform that will sit a chair and a person. What kind of motor (torque rating and etc...) would i need if that person is say 250lbs plus the chair be be able to lift and move without any issues?

Thanks guys!

shannonb1 · Jan 21, 2015

ZYT90-155-12 is a good motor. If you are going to sit in the chair, the gear box will depend on your positioning of your actuator arms. so could be 25:1 or could be 60:1. We would need more design insight.

shannonb1 · Jan 21, 2015

Or this...more power

https://www.motioncontrolproducts.co.uk/products/8/25/zyt90-199-12v-traction-motor-12-nm/

value1 · Jan 21, 2015

Hmmm, tricky one!
I have only seen a hand full of guys in the last few years that came up here with a working 3DOF and even less with a *really* working 3DOF
The thing is that you need 5-10 × the power of a 2DOF because you battle not only against the inertia but also against the weight of the platform and the driver.

If you really want to build a working 3DOF I think there is no way around 3 AC motors with 2 HP each.
And 3 VFD's.
Follow @speedy's thread: http://www.xsimulator.net/community/threads/3-phase-ac-motors-pyramid-simulator.4790/

shannonb1 · Jan 21, 2015

Im assuming you want your 3rd DOF to be sway and not heave?

noorbeast · Jan 21, 2015

Best to do a rough sketch of what you have in mind as a design @Co Tang, that way we can advise accordingly. A budget figure also helps.

Co Tang · Jan 21, 2015

noorbeast said: ↑

Best to do a rough sketch of what you have in mind as a design @Co Tang, that way we can advise accordingly. A budget figure also helps.
Click to expand...

Yeah that probably the best idea is to get something drawn up. I'll see what i can do and get back to you guys.

Thanks.

bsft · Jan 21, 2015

Co Tang said: ↑

Yeah that probably the best idea is to get something drawn up. I'll see what i can do and get back to you guys.

Thanks.
Click to expand...

yep, best way we can advise. see a picture

Co Tang · Jan 22, 2015

bsft said: ↑

yep, best way we can advise. see a picture
Click to expand...

Ok, I did this up in sketchup really quickly. I found a bunch of models and stripped and modded to show you what I want to do. Please note this is not my final design just a concept to get my ideas across. Ok there should be 2 more motors (not shown), two in the back and 1 in the front (total of 3). The chairs sits on a ball joint and the 3 motor arms connects the the two back and one on the front middle. Most of the downward weight will be on the ball and shaft. The motor will "Rock" the chair. This is meant for the occulus rift. Its is not meant to hold monitors or anything like that also I'm trying to get it as compact as I can. So My question is, what motor would work for this and also where would I find a place that sells Ball Joints?

Let me know if this idea would work?

Thanks guys.

noorbeast · Jan 22, 2015

Thanks for the sketch @Co Tang.

You only need 2DOF and hence 2 motors to do what you want. Here is an overview of different 2DOF designs put together by @bsft for inspiration, as motors connecting low down at the rear like in your sketch is the least efficient design: http://www.xsimulator.net/community/threads/different-2dof-sim-builds-feel-free-to-add-designs.5624/

In terms of being compact, on the 2DOF design list you will find @bsft's Desk Racer: http://www.xsimulator.net/community/threads/desk-racer-2dof.5326/

You can also have a look at my DX Racer, which is an evolution of the Desk Racer idea: http://www.xsimulator.net/community/threads/dx-racer-compact-simulator.5866/

Once you have the design nailed down members can advise you as to what sort of motors and other things would work best.

I hope that assists you in formulating some ideas as to what may suit you for your own motion simulator. Please do ask lots of questions along the way, everyone will add ideas, tips and advice.

Good luck with your project, I will look forward to following your progress.

bsft · Jan 22, 2015

Yes I was going to say, build a desk racer style where the motors are at the front a bit and reach up.
That will work better than what you have pictured

Co Tang · Jan 22, 2015

bsft said: ↑

Yes I was going to say, build a desk racer style where the motors are at the front a bit and reach up.
That will work better than what you have pictured
Click to expand...

Just wanted to say that your builds are amazing. It's the reason why I am attempt or even thinking about it. I'm not really a racing fan more of a flight / space sim. So will 2 dof get me what I wants?

noorbeast · Jan 22, 2015

Motion simulation for flight has more compromises than racing, as there is more complex physics at play for loops, rolls and heave.

The biggest challenge is motion simulation for highly acrobatic aircraft, with fast pitch and roll rates, as there is not the time to employ standard tricks such as washout to hide the fact the a motion sim can't physically do a loop or roll. The Elite Dangerous plugin uses angular velocities rather than traditional pitch and roll and @value1 has just added those to Prepar3D as well. That allows a much better way of dealing with high speed rolls.

Heave moving the whole weight of the sim is possible, but gets complicated and expensive. @SeatTime came up with a compact novel alternative, a hinged heave plate: http://www.xsimulator.net/community/threads/seattimes-dc-motor-sim.5024/page-8#post-57008

I find the biggest addition to flight realism is the Oculus Rift. With the Rift I concentrate more on accurate motion cues rather than large movements. You will need to work out what you are aiming for, as there are always compromises to consider.

Co Tang · Jan 22, 2015

noorbeast said: ↑

Motion simulation for flight has more compromises than racing, as there is more complex physics at play for loops, rolls and heave.

The biggest challenge is motion simulation for highly acrobatic aircraft, with fast pitch and roll rates, as there is not the time to employ standard tricks such as washout to hide the fact the a motion sim can't physically do a loop or roll. The Elite Dangerous plugin uses angular velocities rather than traditional pitch and roll and @value1 has just added those to Prepar3D as well. That allows a much better way of dealing with high speed rolls.

Heave moving the whole weight of the sim is possible, but gets complicated and expensive. @SeatTime came up with a compact novel alternative, a hinged heave plate: http://www.xsimulator.net/community/threads/seattimes-dc-motor-sim.5024/page-8#post-57008

I find the biggest addition to flight realism is the Oculus Rift. With the Rift I concentrate more on accurate motion cues rather than large movements. You will need to work out what you are aiming for, as there are always compromises to consider.
Click to expand...

I guess what I am aiming for is front and back pitch along with side to side roll maybe 20 degrees?

I'll attempt the desk racer and built up some mechanical skills and then go from there.

Thanks

noorbeast · Jan 23, 2015

Good plan @Co Tang.

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What size motor to use?

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