Wednesday, May 25, 2016

R2-IQ: Printed Parts

R2-IQ: 3D Printed Parts

Complete Artoo Head
I just received 16 printed parts for R2-IQ.  The process for getting them was a long story...

I designed a couple pieces in SnapCAD (CAD software for VEX IQ) and posted them on the web, asking if anyone could create an stl file.  Within a day, I had a couple offers, and one very good file from David Knerr.

After we made a few tweaks of two parts, Davin printed the parts in one of Purdue Polytechnic's labs.
Assembly of Head
The two parts consist of a triangle-shaped piece (4x) and a diamond-like polygon (12x) which together fill all the area in R2's head.

The design of these parts allowed me to remove much of the internal structure that was required to create the original shape.

Head on body

The most time consuming part of assembling the new head was putting 240 pins into the 3D printed pieces.

Once it was complete, the new head has a lot less panels inside, and is much more rigid than the previous one.

The head is mounted on four rollers, which previously only raised the middle enough to stabilize it.  Now, there is actually a small gap between the head  and the body.

The new design drives a couple small wheels that the head is sitting on.  It's much freer to turn, and slip when people try to turn it manually.
The drive for the head was originally a motor & worm gear that turn an axle connected to the head.  This put a great deal of torque on a couple small pieces, especially when people would walk up and try to turn the head by hand.

Friday, May 20, 2016

R2-IQ: Round Head

R2-IQ: The Round Head

Part 1
The real challenge with R2-IQ has been making it round.  It's one thing to make a cylinder for the body, using the square VEX IQ parts.  It's another thing to make the head.

In SnapCAD (VEX IQ modeling software) I drew up a part that I thought would help.
Part 1 Printed
I posted my picture on line and asked some friends if they could help make a file for a 3D printer.

I received a reply from someone I didn't even know with this drawing that looked better than my original one.

"I didn't know the angles, so I used 70 degrees."

As near as I could tell, I wanted them to be about 18 degrees (or 72, depending on the reference)  In a very short order, he had a new drawing, and thanks to friends (Davin) at Purdue Polytechnic, I had the new part printed in no time.
Part 2 Hole
"Well, that was easy.  But can you make a part to fill this hole?", I challenged David.
Part 2 Hole in CAD
After clarifying some of the angles...
Part 1 actual angle
We discovered the actual angle of the original part should have been about 13 degrees.

I'm not sure how to calculate that angle.  I'm sure someone can.  David did it by lining up all the other parts in CAD and having it tell him the angle.
P2 Original Curve
In no time we had a new part design, which would fill the holes in the head.
P2 Original
After printing it, the part appeared to be a bit too "pointed".  So, instead of it being flush with the red & orange pieces, it was offset to an 11 degree angle.

Basically, I asked him to push the point in, while leaving the attachment points in the same place.
P2 Good Curve
The new (purple) piece has a very nice curve.  In addition, it has enough connection points that I should be able to remove most of the internal structure.

Head with Parts
The first picture of the head with the printed parts installed.

The curve looks very good.

R2-IQ: Filler Parts

R2-IQ at VEX Worlds

I started this post a few weeks ago, and didn't complete it.  

Modified Feet
Before VEX Worlds (in April) I made some tweaks to the feet.  At Brickworld Indy, I had issues with the axles coming out.  So I added more support, and didn't have any issues with them for the 4 days it drove at Worlds.
Small Rebuild
However, I did still have an issue at Worlds.  Turns out trying to back over holes in the floor would cause the legs to buckle and he fell over.
Inside of arm
This is a look inside the arm.  I wasn't sure if I had posted any pictures of the shoulder, so I took this shot.
New Part
I had an idea to fill in the head.  If I can get four of this part, it will allow me to put several plates in place to help create a curve.

This was drawn in SnapCad, and has "wings" at 18 degrees.