3 Degrees of Freedom

[AndyT]

Well, heave is giving me a bit of trouble right now because of the weight that has to be compensated for so, I've removed it from the model to simplify things a bit. At least for now.

The new model can be found here:
http://geocities.com/andytulenko/3dof.bmp

I did something a little different this time. I took small bits of the picture and placed them below it to better identify the parts. I hope it makes it easier for you. If not, just let me know.

A.......Green- This is the cockpit platform itself.
B.......Yellow- This is a 'cup' shaped peice of steel that the platform mounts on. Inside it is a modified U-Joint The U-joint in turn mounts to item D.
C.......Blue- This is a steel plate mounted on the outside of the cup part B.
D.......Yellow- This is the 'driveshaft' that mounts to the base E
E.......Black- The base you mount everything to.

M1.....This is the Pitch motor.
M2.....The Roll motor.
M3.....The Yaw motor.
This would actually be mounted at position M3a but is here for illustration only. The mount is flexible in an up and down direction but not rotationaly.

I think this one is pretty self explanatory except for the modified U-joint I mentioned. As soon as I can get the time to make the picture, I'll add it in here, but remember, it has to make provision for the Slip Ring. There is another option for the placement of the slip ring. On TOP of the cockpit itself. This way, you can use a standard U-Joint on the bottom like Jim did and still have freedom of movement. Of course, you will have to build some method to hang it from above, but that should be very easy for any of us.

There is a new development that I'm adding into this one however. Instead of using the small power wiper motors like Jim used, I'd like to try and use 3 small 12vdc winch motors that are rated 2000 pounds each. That should be more than enough to handle the weight. For a faster sim, place gears on them to increase the rotation by 10. As I have them designed here, they have an arm that is attached to the shaft of the motor and then connects to the platform control arm.

M1 is placed under the steel plate to increase the amount of pitch you can generate. You could do the same with the roll motor also.

Questions? Comments?

[Jim NZ]

Hi Andy ... Maybe I'm a bit thick here... I just cant see something and need a bit of help to understand your concept.

If A is mounted on B and C is also mounted on B, then how do you get the pitch and roll ?? I know in there there is a U joint but in my thick head, if that being the case, the drive for the yaw (C) would be moving away from the yaw motor.

Can you explain a wee bit more ???

By the way, the yaw bearing .. Where is it. ??
A thing on yaw bearings... There is terrific force on them and they need to be strong. I am using 200kg offset by 3 feet and that really puts on the pressure. Using a trailer hub as I was going to do was just not good enough. I upsized to a small truck hubb which also gave me the hole for the mercotac unit.

I think you could be on to something though Andy.

Keep fiddling ... Jim NZ
www.jimspage.co.nz