Discussion of Observed Results
The prototype was built and tested to the exact specifications that were generated through-out this report, however the observed results were not what the team had expected to see. The robot was expected to travel through the fluid at a measureable 5mm/sec; however it stayed in one place and simply vibrated in position. From this observation, the first impulse of the team was that the head section was not heavy or large enough to provide a counter-moment capable of holding the cantilevered end of the tail steady, which would negate the force generated by the tails motions. The team tested this hypothesis by removing the original head and creating a larger version that would be heavier than the original head as well as flat, to provide a high resistive moment. This design also produced no forward motion but it did reduce the visible vibrations seen in the robot.
The team reviewed the assumptions made about how the robot would behave at a microscopic level and came to the conclusion that the only explanation that could explain the observed results was that we failed to account for how momentum would behave at a microscopic level. The robot was producing a theoretical force capable of propelling the robot forward, but the tail moved up and down in the same path. If we consider this identical move path as well as the possibility that a highly viscous environment would reduce the momentum of a small prototype to near zero; it can be concluded that the time it takes the tail to move will have no affect on its forward progression. This idea is consistent because a faster move time would require a higher force output to overcome the high viscosity, but as the tail moved back into a resting position, even at a slower rate, it would still only be displacing the same volume of fluid. The high viscosity of the fluid means it behaves more like a solid, in the sense that the molecules have a more rigid structure than a fluid we are more familiar with. The combination of high fluid viscosity, strong intermolecular bonds, and time independence mean that future designs regarding a micro-underwater robot will need to explore designs that produce tail motion that does not move between its four states in an identical manner.
Areas For Improvement
The design could be improved upon by removing the second actuator which is working in parallel and instead have it act in series. This would allow the robot to create a tail move profile that is no longer identical in its motion and would instead be asymmetrical. A design like this could continue with the numbers produced by this team for benchmarking and would focus primarily on designing a control system that would be able to interact with both actuators and have them move in time with each other to develop forward motion. The project would require a multi-disciplinary team as a greater understanding of circuitry would be needed to build the required custom interface needed to drive the actuators from a single input function.
Conclusion
Even thought the project was not a success in the traditional sense of the word, our design team was able to walk away with a greater respect and understanding of the total design process. We went from nothing more than an initial idea and created a design that was able to be tested with expected, quantifiable outcomes. Even though we did not achieve the results we were hoping to see, the team was able to learn more about the behavior of micro-scale robots and how they behave in high viscous environments. The results that were observed and discussed in this report will grant future groups who attempt this project a better understanding of the behavior of mirco-scale objects and what actions and designs can be implemented to rectify the obstacles that were encountered during this design process.
