$URL: svn+ssh://aaron@birenboim.com/home/users/svn/Jansen/trunk/Building.html $
$Id: Building.html 227 2013-09-10 17:27:15Z aaron $

Building Mr. What's Walking Linkage

This drawing will help explain my conventions for naming parts of the linkage: install OpenSCAD, then type make;make misc in this folder. It should generate all the individual parts models you will need.

Then, for each balanced leg pair, print: main, crankLinks, mBED, mFeet, BH4, EF4
For a full robot chassis, you may also want two each of: electronicsMount, motorMount, basketMount, pulley, drivePulley
See Makefile for rules to generate drawings of individual parts.

Building from .stl

If you have your own 3D printer, it might be wise to prepare prints from the base STL drawings yourself. In order to build a complete 8-legged robot, you will need: You will need two drive pulleys, and two main pulleys. The design on these is changing. You will need (2) of each if looking at a complete pulley drawing, but (4) of each if the current pulley design is built by glueing two pulleys together.

If you have a photoresin printer, you may want to complete the forks on the BED triangle, instead of printing separate forks. Unfortunately, I do not have a drawing for that at this time. You will need to take the small fork tine assembly, rotate it, and place it as a mirror image of the matching assembly on the BED triangle.

For a complete chassis hardware setup, you will want

For current (spacer) 3D printed version:

Plotting

To generate data for plotting the walking cycle, run
     java -cp <folder_containing_com_binary> com.boim.walker.tests.DumpMetric Jansen <linkage lengths in standard order, as above>
This will generate an orbit.dat file. Load this file into octave/MATLAB, a=load('orbit.dat'); and plot with plotJansenOrbit(a).

Plots can be converted to animated .gif's with a command like:

     convert -remap orbit00.png -crop 768x512+100+120 +repage orbit44.png cropped44.png
The -remap tells convert to use the 8-bit colormap from the first frame, and +repage is necessary to force the image to resize, not just set stuff outside the crop area to "unused".

To create an animated gif, delay between frames is in 1/100ths of a second:

     convert -delay 20 cropped??.png cropped.gif

Drills

After 3D printing the linkage, holes need to be precision drilled.
BitNotes
17/64" free on 1/4" standoffs
#10 free on 3/16" OD brass tube, used for B axle
#11 free on 3/16" OD brass tube and spacer, if "polished" after drill
#12 Snug (but not press-fit) on 3/16" OD brass tube, used for B axle
#31 tight on 1/8 brass, as used on crank arm
#30 free on 1/8 brass, good for cranklinks, main
#35 snug, but free around #4-40 screw
#40 barely threads a #4-40 screw
Last modified: Mon Sep 9 18:07:27 MDT 2013