tino
Junior Member
Posts: 71
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Post by tino on Oct 9, 2015 16:19:46 GMT
Hi all, I've been looking into building a small 6dof motion platform for use with VR headsets and 1080p projector for a while now so this is probably a good time to create a thread. This is the motor I'll be using: www.aliexpress.com/item/Golf-Trolley-Motor-dc-motor-with-carbon-brush-with-CE-12VDC-150W-ratio-26-1/293841828.htmlI'm using pololu 18v25 H bridge. Motor in action: youtu.be/bDrCTqwTjy0(100% motor speed, PID P at 25, not done much tweaking yet) Motor is rated about 14Nm @ 120 RPM and plan to further gear it down using minimoto (mini quadbike) sprockets and 25H chain. With about 7:1 sprocket ratio I should get ~ 95 Nm at 17.14 RPM (although I'll try running the motors at 13 or 14 V for a bit of extra umph). 11cm lever travelling at 17.14 RPM should give about 20cm/sec linear speed at 12V. PSU www.ebay.com/itm/IBM-74P4452-BladeCenter-2000W-Delta-DPS-2000BB-/400962170384?hash=item5d5b352e10 (I got the version which allows voltage adjustments up to 14.6 V with potentiometer.) and 12V car battery in parallel. I originally planned to weld steel for the bottom platform, but lately I've been looking more and more at birch plywood since Steven got very good results from it. (The only problem might be sudden flooding Aluminium profiles also look great, but they seem to be very pricey. I won't have to to a lot of work on top platform as I'm using Fanatec CSL. This seat is aluminium, total weight 12kg and comes with wheel and pedal stands. I've noticed that most 6dof platforms here are using this design (triangle tip is front): bffsimulation.com/Manual-6DOF/Introduction.phpDo you see any problems reversing the design 180 deg so triangle tip is rear? Which design would handle the load better? This is the motor layout I had in mind (motors inside, levers outside ) seems very compact and will probably work well with addition of some support legs on the tips of the triangle. www.youtube.com/watch?v=uye-A-fUfdQThat's all for now, hopefully I'll have more updates soon. All the best. Tino.
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edk
New Member
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Post by edk on Apr 18, 2016 4:50:34 GMT
Any work done on this?
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tino
Junior Member
Posts: 71
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Post by tino on Apr 18, 2016 10:16:59 GMT
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Post by paulg100 on Apr 18, 2016 15:53:46 GMT
"I've noticed that most 6dof platforms here are using this design (triangle tip is front): bffsimulation.com/Manual-6DOF/Introduction.php Do you see any problems reversing the design 180 deg so triangle tip is rear?" Which design would handle the load better?
This is something id be very interested to know also. Probably for a different reason, but if tip is at the back then this could allow space to drop seat lower down to lower COG and still have legs to exit from front for peddles etc.
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Post by hexpod on Apr 18, 2016 19:03:36 GMT
you can notice that in my design front/back are reversed.
cheers.
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tino
Junior Member
Posts: 71
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Post by tino on Apr 18, 2016 22:55:30 GMT
you can notice that in my design front/back are reversed.
cheers.
Yes, looks like it's working well! What was the main reason, compact design or better load characteristics? Did you manage to measure or calculate your platform speed? Regards.
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Post by hexpod on Apr 18, 2016 23:08:21 GMT
you can notice that in my design front/back are reversed.
cheers.
Yes, looks like it's working well! What was the main reason, compact design or better load characteristics? Did you manage to measure or calculate your platform speed? Regards. The reason was the support legs. it was possible only that way keeping such a small footprint. 1.2 square meter (computer included).
try to do smaller :-)
In speed I was first aiming 30 rpm than forced to reduce to 14 rpm... long story.
I would say, 14 is the lower reasonable limit with 160mm levers
cheers.
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tino
Junior Member
Posts: 71
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Post by tino on Apr 24, 2016 12:44:05 GMT
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Post by hexpod on Apr 24, 2016 17:30:43 GMT
Thanks hexpod, What would be the best the best way to ensure that DC motors don't start spinning freely (and wrecking the platform) in case of potentiometer failure? hard-stop is the most secure solution. I've experienced already (after an emergency cut off) the platform going from the upper position to the unwanted, mechanically unpleasant locations, because of the lack of the bottom hard-stop.
I am advising at least one at the bottom. If you implement two, bottom/top, than you are secure.
cheers
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tino
Junior Member
Posts: 71
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Post by tino on Apr 24, 2016 21:26:46 GMT
hard-stop is the most secure solution. I've experienced already (after an emergency cut off) the platform going from the upper position to the unwanted, mechanically unpleasant locations, because of the lack of the bottom hard-stop.
I am advising at least one at the bottom. If you implement two, bottom/top, than you are secure.
cheers
Thanks! I agree, much better to be safe than sorry. I'll do a bit of research on hard stops, Ideally I'd like to automatically stop (or maybe reverse) the motor if the lever is about to go out of safe bounds. If you, or anyone else have any links or diagrams, or advice how to connect it, I'd be happy to hear
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tino
Junior Member
Posts: 71
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Post by tino on Apr 24, 2016 23:04:56 GMT
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tino
Junior Member
Posts: 71
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Post by tino on Oct 24, 2017 12:53:28 GMT
Hi all, Here is a quick update on my progress. Unfortunately PWM channel1 on my AMC1280USB is not working, so I'm waiting for a new board from kickstarter campaign. (Will post more info with digital oscilloscope later) I've completed most of the main metal work, sprocket system seems to be working well, just finishing touches left to do. I decided to go with triple 20" monitors and head tracking (Track IR) for now, VR headset is definitely planned, probably when 2nd revision of Oculus rift or HTC Vive come out. I'm having mixed feelings about pololu controllers, nothing wrong with them, but since they are very small, they are not very friendly to solder for beginners, also they don't have any kind of over current or temperature protection. One of my pololu drivers never worked well (would shut off after 20-30 seconds of use), and recently it stopped working at all (controllers were ordered in 2014 so out of warranty). I've ordered another one, but I'm slowly drifting toward ordering 3X Sabertooth Dual 32A controllers. They are slight more expensive then pololu, but seem more robust and easier to wire up. Here are some pics: (spaghetti western) Seat with monitors attached (before painting): Motors in motion (only 5 for now
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tino
Junior Member
Posts: 71
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Post by tino on Oct 24, 2017 21:50:04 GMT
Here is a better picture of the platform: Is anyone using X-sim on Windows 10? I'm having a lot of issues with the Extractor app, it's crashing constantly, I've asked for help on x-sim.de forums, but so far it seems that I might have to downgrade to Windows 7. Incidentally, Xsimulator software seems to be working much better on Windows 10, haven't had a single crash yet...
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Post by baulchen1234 on Nov 3, 2017 18:33:01 GMT
Hi all, Here is a quick update on my progress. Unfortunately PWM channel1 on my AMC1280USB is not working, so I'm waiting for a new board from kickstarter campaign. (Will post more info with digital oscilloscope later) I've completed most of the main metal work, sprocket system seems to be working well, just finishing touches left to do. I decided to go with triple 20" monitors and head tracking (Track IR) for now, VR headset is definitely planned, probably when 2nd revision of Oculus rift or HTC Vive come out. I'm having mixed feelings about pololu controllers, nothing wrong with them, but since they are very small, they are not very friendly to solder for beginners, also they don't have any kind of over current or temperature protection. One of my pololu drivers never worked well (would shut off after 20-30 seconds of use), and recently it stopped working at all (controllers were ordered in 2014 so out of warranty). I've ordered another one, but I'm slowly drifting toward ordering 3X Sabertooth Dual 32A controllers. They are slight more expensive then pololu, but seem more robust and easier to wire up. Here are some pics: (spaghetti western) Seat with monitors attached (before painting): Motors in motion (only 5 for now
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tino
Junior Member
Posts: 71
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Post by tino on Dec 31, 2017 19:38:29 GMT
Happy New Year everyone! Just a quick update, I've finished the simulator with Sabertooth 2x32 controllers, (my amc1280 from kicksterter has not arrived yet) Triple screens worked well, but I've decided to use 1080p projector for now. I've been having problems with motor 2, I've tried switching around sabertotoh controllers, cables, potentiates etc, but I think the fault might be with Thanos card. It shows most often using heave motion in 6dof.exe , every so often motor 2 ends up going in opposite direction, did anyone else have a similar issue? When is the eta for kickstarter cards?
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