Tuesday, February 4, 2014

Bumper Success! (And Shoulder Update)

After spending way too much time I was finally able to model the front lower corner bumpers! I had to change some geometry of the structure behind the bumper and using several lofts and intersection curves, I was able to make them, finally!

It does make him look a lot better than before, huh? It feels more complete now (even though I'm not!)

I know it's not perfectly the same as the real WALL-E but I'm fine with how it turned out and I don't want to spend any more time on this.

On of the bad things is that I'll probably have to 3D print this piece, like I'll probably do for the rear bumpers as well. Let's see how much it'll cost...

For the basic white plastic it'll cost:

Shapeways: $112
i.materialise: $208
Scultpeo: $128

Yikes... that's a little bit on the pricey side. Fortunately, Shapeways sells the ceramic version for $33 which I could probably make a rubber mold of.. but I would still need to purchase 2 of them (LH and RH). 

i.materialise does sell the multicolor material version for $69. Hmmm...

Time for a break and then I'll be back for more!

Update: Here's what I have so far for the shoulder joint:

It's a little difficult to see what it is so I'll try to explain. The lower piece is the component that will go into the body. The upper piece is the upper clevis where shoulder meets the body.

Here's a view looking downwards a little bit. That top piece attached to the shaft is a face mounted shaft collar. You can also see the cut out for the wiring that will eventually go through to the arms and fingers.

... and here's the side view. So, as you can see, a timing belt running from inside the body will connect to the timing pulley on the lower piece. The timing pulley and the shaft collar are locked onto the shaft so when the timing pulley turns, it'll turn the shaft collar as well. The shaft collar has a face mount so it'll attach to the rest of the arm and allow it to pivot. Underneath all this will the second clevis and I'm still deciding whether or not to add a second shaft collar on there to mirror the top portion. These pieces are not cheap... :(

The other way of achieving the shoulder pivot would probably be to use some sort of linear actuator and attach it a little ways from the pivot point. It would probably require less power due to the leverage but it might be deviating from the real WALL-E a bit...

Another way is to possibly use a worm drive. The worm would come in at an angle and the worm gear would be where the timing pulley is. The only problem with that is the cost. I think it'll end up being somewhere 2-3 times more expensive just for the hardware like the worm and worm gear versus the timing pulleys and belts.

Anyways, everything is subject to change and if I find something better, I'll change my design. But until then, I'll continue on with the rest of the arm tomorrow!

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