7) Conclusion - Group 6

Future work:

• Ball joint instead of heat shrink tube

The plan to CAD and print the ball and socket joint was abandoned since the original oar is slim, and the coupling ball had to be designed to be even thinner. The dimensions resulted in the print being too weak, so we had to devise another component to simulate a ball and socket joint.

However, for the final build, we changed the dimensions of the oar to make it look more proportional to the bigger size of the boat base. The new dimensions could have allowed for a more comfortable and sturdy design of the ball and socket joint to couple the oar with the rest of the linkage system. In the future, we might consider ordering a premade ball-socket joint to ensure reliability.

In general, we are happy with the shown result though, since we improvised the half joint rather successfully using a heat shrink that joined both pieces and allowed for the desired range of motion. 

• Size of linkage system(bigger; for bigger trajectory)

The novel nature of the linkage system demanded that during the process there would be some amount of experimentation. Having never designed a six-bar linkage system from scratch, our philosophy in choosing the size of the links and axles was that, if we missed the mark for optimal dimensions, our prototype would be easily fixed by reprinting a problematic (non-fitting) link. Therefore, it was decided that we would use a relatively compact size and density during prints. This meant scaling down the dimensions of the designed trajectory but also a more flexible manufacturing process where reprinting a piece would not take very long and was easily interchanged. Thus, we also decided on a more modular approach to the assembly. Any piece was rather simply replaced or interchanged by disconnecting the axles and surrounding pieces and removing them.

The result was a non-strictly-planar motion. This means the mechanism was not sliding perfectly in one plane but also in a second one slightly. While it could certainly be described as some sort of “play”, we decided that restraining the linkage system to be sturdier would put too much stress on the pivot section of the oar component, possibly snapping into place. Hence, some out-of-plane motion was to be tolerated.

If we were to do a second version of the robot, we would experiment with incorporating sturdier axles and links, and with reducing the dimensions tolerances. This would require the ball joint to be a solidly manufactured component to withstand the stress on the oar and pivot.

Learnings and conclusions:

Overall, one thing we learned when designing, manufacturing, and assembling the robot was that, in inventing and coming up with a novel build, the iterative approach is especially satisfactory.

The first step for the project was a sort of prebuild. We came together to imagine the components that would be necessary to put the robot together and we then had to put that into words and specific components in the Bill of Materials (BOM).

Decisions and compromises had to be made, and through these, we exercised and therefore improved some executive and decision-making skills. In developing the robot, we went through different iterations and had to adapt components to create the best possible version we could.

The future possible fixes mentioned at the start of this page are valuable opportunities, but overall we were also pleased with the model we put together and what we learned from the process along the way.