First illustration design flaws:

• Upon initial review of the 3-d model, we determined the pieces were too long to fit the sides on top of the bottom, and that the holes weren’t aligned which in turn meant the motors weren’t aligned.

• In the original design, the pieces were supposed to fit on top of the bottom piece. This could have been what was causing issues with the strength of our box; the box itself was not sturdy enough to hold the weight of the motors without bowing.

Problems with acrylic

• If a sturdier material than acrylic was used, the movement would not be compromised. The box can not hold the weight of the motors which is causing it to cave in. The holes themselves have become slightly shifted which throws off the symmetry. Without symmetry, the movement will be out of sync with what the code is telling it to do. Even if just slightly, since our robot is a writing robot, precision is everything. If we had access, we would reprint with a sturdier option or rebuild from wood.

Figure 2. Front of Proposal Bot V1

Traction issue on rollers

• The movement of our v1 proposal bot was not ideal. Part of this was due to the traction on the rollers being poor. With no grip, the slick plastic couldn’t properly navigate the even slicker surface. To combat this, we dipped the wheels in Plasti Dip. Fully coated caused issues with the wheel now being too thick for the wheel well. However with the dip only around the center of the wheel, an improvement was noticed.

Figure 3. Rollers with Plastidip

Rod size issue

• The rods used in the wheels in the first construction of our box were a size slightly too thin, as the exact size wasn’t able to be tracked down in time for the v1 demo. This caused the wheels to move too much out of place which led to a wonky performance. The correct rods were acquired and the old ones were replaced which seemed to help with proper movement.

Figure 1. V2 Rods vs V1 Rods