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BRAK Project-> Design info-> Mechanics-> New base goals
New Mobile Base Design Goals
The old mobile base worked, but it had some problems. I learned to live with them but always wished I had the opportunity to correct them. Now I do. So here are some revised goals for the new mobile base, given my experience with the original design:- Easier to manufacture. We ran into problems on the old base when it came to making the two major base plates, specifically with getting the bearing holes to line up.
- Easier to assemble and disassemble. The old base design originally had idler pulleys to tension each belt. We ended up not using any since the belts were tight enough without them. However, to actually get the belts onto the pulleys meant we either had to stretch them and slide them into place, or we had to put them on the pulleys before putting the pulleys onto each shaft. I want a design which lets us put the belts in place, then move the pulleys/shafts into place while keeping the proper alignment. I also want to make the various pieces which need adjustment easier to access.
- Less heavy. The old mobile base was over-engineered; lots of thick aluminum plates. I want the new base to have a lighter (yet rigid) chassis which everything else "bolts onto", and only include plates where they are actually needed.
- More precise steering. I quickly discovered that the steering motor on the old mobile base had too little torque at low speeds, which is where we really needed it (for "precise" steering). We retrofitted the design to fix this, but because of how the motors were positioned it was very awkward to assemble.
- Less beauty, more simplicity. An original goal was to make everything as symmetric as possible. The problem is not everything has to be symmetric. With all due respect to my right brain, I decided to favor simplicity of manufacturing over symmetry when possible.