Flat Subtractor
A new, compact, streamlined subtractor design. Free building instructions available.
I have designed a number of subtractors long ago, and all of these designs are available in my book. However, they all share one feature: multiple layer of gears, making these designs somewhat tall and not always easily incorporated in models. With this new design, my goal was to address this issue. It’s essentially a simplified, streamlined version of my old longitudinal subtractor which has only one layer of gears and hence it’s as flat as it gets. Compared to the old design, it also sports one gear wheel less.
Building instructions available here: sariel.pl/downloads/
Other than being very flat, this is a fairly standard subtractor design with two outputs corresponding to drive sprockets in left and right track, and two inputs: one for driving straight and one for steering. It’s possible to connect multiple motors to either of these inputs and to use different gear ratio for each. For example you typically need much lower speed for steering than driving, so you can use two strong motors for driving, with high gear ratio, and one weak motor for steering, with lower gear ratio.
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