15-394 Assignment 2: Build an Automaton
Design
- Design an automaton in SolidWorks. It should be a cam-driven
automaton like the ones we saw in the videos, with at least four
moving figures. It must be three-dimensional, not planar,
meaning that the segments of your automaton cannot all move in the
same plane the way the LittleMan automaton did. A hand crank should
power the mechanism. Nothing other than the crank should be
hand-driven.
- To start, download
FrameParts.zip, and
LinearBushingPatterns.zip,
and inspect their contents. You can use these as a starting point
for your design. The example frame should be modified to provide
for four figures and any other changes you need to support your
specific automaton design. There are two choices for linear bushing
with subtly different shapes: LinearBushingPattern_10_6_50 and
LinearBushingPattern_10_6_65. They both have 10 cutouts, but the
cutouts are a tiny bit wider in the former design.
- At least one of the four figures in your automaton must implement
rotational motion, and at least one must use a cam with linear
bushing. The rest is up to you. Please see the example automaton in
IDeATe for an idea of what you should do.
- Materials provided: 12x24 inch hardboard (3/16 inch thickness);
1/2 inch diameter wooden dowel; 1/4 inch diameter delrin rods (6
inches long; you can cut them shorter) to serve as cam
followers.
- Designing your automaton involves making the cam parts, gears,
and crank handle, and designing the figures and any background
scenery required. Attach the stabilizing rings to the camshaft,
located outside of the side panels, to help prevent the camshaft
from slipping left or right, which could cause the dowels to
fall off the cams.
Simulate
- Simulate your automaton in SolidWorks. Remember to turn on
SolidWorks Motion in the SolidWorks Add-Ins tab, and then change
the animation type from "Animation" to "Motion Study".
- Save an animation file from your simulation. To do this, click
on the Save Animation button which is in the same row as the Motor,
Damper, and Solid Body Contact buttons, but further to the left. Use
the AVI file format. Be careful not to make the file size too big;
keep it below 40 MB.
- Some tips: You can use cam mates to simulate cam motion in your
mode, but cam mates don’t work well in motion analysis. Instead
of relying on these for the analysis, make solid body contacts
and add gravity. Also, use a solid body contact between the
gears; otherwise the top gear will slip through or slide down
the camshaft.
- Don't make the cams too pointy or they will get stuck on the
dowels during the motion analysis, and the physical device might
bind.
- Use "lock" mates to attach the cams to the camshaft instead of
checking the "lock" checkbox in the coincident mate. The latter
won't work in motion analysis, but lock mates do work.
Fabricate and Assemble
- Laser cut your parts using some combination of
Masonite/hardboard, wood, cardboard, and acrylic. It might be a
good idea to cut each cam twice and double them up; thicker cams
make it easier for the delrin cam followers to stay in place.
- Use 4-40 hardware to assemble the frame. use either brass
round-headed fasteners or 4-40 screws to assemble the other parts of
your mechanism.
- Use a glue gun (available at IDeATe) to attach the cams and crank
handle to the camshaft. You can also use it to glue two cams together
to make a thicker one. We also have wood glue and other kinds of glue at the Glue Station
in room A5, just outside the laser cutter room.
- For the artistically inclined: color your components by painting
them, drawing on them, applying stickers or decals, etc.
Document
Generate a realistic rendering of your mechanism in SolidWorks:
- Assign materials to your parts. To do this, open each part file
and, in the feature manager tree, right click on Materials. You can
either choose one of the popular materials listed in the pop-up menu,
or choose Edit Material for a wider range of choices.
- Go back the assembly and verify that your parts are colored
correctly. You may need to remove an existing appearance attribute in
order to see the material's color. To do that, click on the part,
click on the beach ball (Appearances icon), and click on the red X to
remove any unwanted appearance attributes.
- Go to the SolidWorks Add-Ins tab and select PhotoView 360.
- A new tab will appear to the left of SolidWorks Add-Ins called
"Render Tools". Switch to the Render Tools tab.
- Click on Edit Scene, and in the "Appearances, Scenes, and Decals"
menu on the right side, click on one of the basic scenes, such as
"3-point faded", and drag it into the graphics window.
- Click on the green checkmark to accept that scene, or click on
the red "X" to choose a different one.
- Click on the Preview Window button to see what the final
rendering will look like. You may need to rotate or translate your
part, or zoom in or out, to get the view you want.
- Click on the Options button to adjust the resolution of the
rendered image. The default is probably good enough, but you can
change it if you wish.
- Click on the Final Render button to pop up a Final Render window
and generate the rendering. This will take a little while.
- Click on the Save Image button in the Final Render window and save your image.
Take a photograph of your actual automaton.
Post the rendering and the picture to Piazza in the thread provided for this purpose.
Hand-In
Hand in a zip file handin.zip containing the following:
- Your SolidWorks part and assembly files, and your DXF files.
- Your animation file.
- Your rendering image.
Due date: check the class schedule.
Grading (20 pts)
- 10 pts - Design: at least four cams (or equivalent) in your automaton; different/custom character; motion in more than one plane
- 6 pts - Fabrication: laser cut and assembled automaton.
- 4 pt - Files: Source files, images, and animation.
- 2 pts - BONUS: possible extra points for extraordinary creativity (multiple characters, interesting links, colorful, etc.)
Gallery of Past Projects
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