theorical question about 3dof motors

[ferslash]

i guess i can not be done... because using 6dof there is not central spring right?

best regards

fer

[prilad]

[prilad]

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?

gui for mine firmware, not for Thanos's... And with GUI you can see feedback data on the graphics for easy setting PID coefficients...

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?

In Russia thay says - nature can not be fooled... Yes, you can INCREASE motor force by the levers (this is good news) but in this moment you DECREASE movement distance (and this is bad news)...
For example: Our lovely wiper with torgue 5.5 N*m with lever 50 mm have moment at the end of lever 5.5 / 0.05 = 110 N and moving distance 100 mm ( 2*50mm from top to bottom) If we decrease lever length to 10 mm moment will be 5.5 / 0.01 = 550 N (!!!) but moving distance was only 20mm

IMHO.

Regards,
Ale

[prilad]

ups

[ScottSim]

Hi Guys,
Ok, so wipers are out, what is the next step up?
DC is just so much safer and for those not familiar with AC, DC easier to understand and play + appear cheaper option;
Motiondave has plenty of DC experiance with sim rigs, MD, do you wish to coment?

I am getting ready for another build, hhmmmm cost efective 3dof

These are on sale http://www.motiondynamics.com.au/worm-drive-motor-12v-24v-200w-180-rpm-20nm-torque.html

[DEADBEEF]

Has anyone considered using torsion springs to carry the weight of the motion platform?

Here's a quick pic of a rig design I knocked up the other day...

(click for bigger)

(ignore the motor/pulley bit, I was just playing with different motor layouts).

The red spring is a torsion spring similar to those used in garage doors. One end is attached to the shaft mount, the other is wound up under tension then attached to the shaft.

It's wound up so that the torque applied by the spring roughly equals the mass of the motion platform & rider at the end of the lever arm (or rather, a third of it).

Then the motors only have to worry about moving the platform and not carrying the full mass of the rig.

---

NB, I also designed the rig to be expandable and modular, as I'm on a somewhat limited budget.

* You can start with 2DOF.
* Then convert it to 3DOF by adding an extra motor & controller.
* Then convert it to 4DOF by adding three smaller motors and wheels.

[ferslash]

man that design seams preatty interesting, so we could use cheap motors and achieve grate movement.... i dont get exactly the spring stuff (i am not a native english speaker) but i will google to get it better (i mean i dont understand exactly how the springs helps)

on the other hand, lets invite some mechanical guys to this topic so they can tell us.

thanks for sharing your idea.

fer

(are you planning to execute it, or it is just a theorical desingn?)

[DEADBEEF]

i dont get exactly the spring stuff

Think of how this type of mouse trap works. The spring is wrapped around the pivot axis, which then uses torsion as opposed to tension or compression to store energy in the spring. The spring then exerts a downward force on the base and an upward force on the bar.

Scale this up to the size of a sim rig and the upward force the spring is exerting is now counteracting the downward force from the weight of the motion platform and rider. This is also how garage doors hold the weight of the door, making it possible to open/close them single handedly.

(are you planning to execute it, or it is just a theorical desingn?)

A bit of both to be honest.
I've gathered a bunch of the electric components for what will eventually be my motion rig but have been evaluating various designs before I actually start building anything.

I made a minor change to the SketchyPhysics plugin for Google Sketchup so we can test Sketchup designs using realtime telemetry data from X-Sim
...so you can simulate your simulator (Yo Dawg!).

Here's a quick video I made showing a couple of quick designs I knocked up to test the plugin....


NB: This was really just for testing that the plugin works properly. The math profiles weren't really set up very well. For one, the pitch axis was accidentally inverted :/
Also, the framerate was terrible due to the screen recording. Otherwise it runs really smoothly.

I need to write up some documentation then I'll make a new topic for this as I'm sure it'll be pretty handy for other people who are designing motion rigs.

[sirnoname]

wow, can we continue in the cad forum with your plugin?
We did had same idea but noone did have knowlege about the plugin interface.
We have some ready models there ...
Did activate your access rights.

[value1]

Fantastic! I've been using SketchyPhysics for the design of my simrig but actually wasn't clever enough to figure out how to connect it with telemetry data.

Very smart job, DEADBEEF!