Otto Bot More Stable

A project log for Otto LC

A Laser cut chassis for the Otto DIY robot.

Florian FestiFlorian Festi 12/18/2017 at 23:190 Comments

The Otto Bot had still been in the "Unstable" group all the time. Very soon next year a school class is going to build a whole set of Otto Bots. Also there is not much left to do. I did some last tweaks and set the default for leg length to 34mm instead of 37. This is barely enough to fit the servo in but makes the robot a bit more stable.

This makes it stable enough to move it into the "Misc" category.

As we are going to laser cut a bigger number (ok, only 15ish) of Otto Bots having to deal with separate pieces would be a pain in the ass. So I added a new "tab" feature that add little gaps in the circumference of the parts. Right now it is only supported for Edge classes and straight lines.

While proper Edges get the tabs automatically parts drawn "by hand" with .edge() and .corner() or .polyline() need to get their tabs also added by hand. I will add tabs to corners in the future but the situation there is a bit more complicated (and not as pressing).

First tests have shown that value of 0.2mm works well  with our laser cutter. The parts stay in the sheet but are easy to snap out.  Making the tabs bigger results in a surprisingly strong connection of the between the pieces and their surrounding.

In theory the tabs should be enlarged by "burn" on both ends. But "burn" is not only used to adjust for the width of the cut but also the determines the stiffness of the fit between parts. So I rather decouple burn and and tabs. This way the proper value for the tabs will just work no matter what burn value is used.