Self Evaluation

Self Evaluation
Andrew Feiter
Systems Engineering II

Over the past year I have been working on design for a robotic arm, my senior design project, for the MATEs competition. My project was only one part of the ROV that was going to compete in the competition in late April. My projects role in the overall scheme of the competition was for the design to be able to help complete the missions that were set down by MATES.
The final solution chosen to complete the tasks at the competition ( pick up rock crabs off the floor, grasp rocks attached to a vent pipe, and take the temperature of the surrounding water) was designed to perform all the necessary tasks. The design was contained in a polycarbonate housing to protect the arm and the gear system that powered it. The gear system was a simple worm geared system, that is it a motor, in this case a small DC motor, turns a shaft which then turns the worm gear which then turns the two helical gears connected to it, which turn the claws in opposite directions. The motor was designed to be sealed in a water tight compartment in the back of the housing, to help keep the motor waterproof and to give the ROV positive buoyancy. The claws were made of the same polycarbonate as the housing so they would be able to handle any collisions with any objects that the ROV would encounter during the missions. The arm was to be held together with a combination of screws and epoxy to help ensure a strong tight seal. The arm was to be attached to the ROV by nuts and bolts and was to sit centered on the ROV.
During the design process and construction phase of the project a couple of things changed in the design of the arm. The first and most noticeable was the addition of an extra set of claws. The extra set of claws was added at the end of the construction to help the arm grab objects that would sit lower than the claws that were positioned already on the arm. This was required because the arm design did not take into account the height of the objects off the pool floor. The new claws were made of hard pre fashioned plastic, an epoxy piece of polycarbonate which held a rubber grip for claw. Another discrepancy was the way arm was water sealed. In the original design the housing itself was supposed to keep the motor’s area watertight, however after testing it multiple times it was evident things had to be sealed another way. It was decided to use epoxy to seal all the areas water was leaking from in hope of sealing the arm.
While working on the project I encountered numerous success and failures. One of the success I encountered was in the very beginning of the project was getting all of my items ordered in a timely fashion. After going through the arduous of the ordering process it was a huge success to have everything ordered and in the process of delivery on timed after spending countless classes trying to find and order the items. Another success that I had while completing this project was when I finally assembled the whole project before the competition. For weeks on end I had been working hard to try to complete the arm, and when the final product was finally put together it was a great success in my eyes. The final success that I encountered during this project was when the motor and gear system worked when it was tested. When the preliminary testing went on the motor and gear system worked together proving the design worked. Along the way I also encountered numerous failures. The first of the failures was not getting my desired gears, which were made of steel and were industrial grade, this were not procured because of issues with the bid process. Another failure I encountered was the failing of the arm after the initial test. After the initial test the arm ceased working because of unforeseen issues with the motor shaft. The final failure I encountered was at the competition itself. The arm housing which was supposed to be waterproof leaked after additional waterproofing the nights before, causing the ROV to weigh too much and sink.
This whole process was learning experience especially the failures. One of the first things I learned from my failures is to manage my time better. With the bid process I assumed I would be able to get my gear system with ease and it would be in the lab long before construction began, however I was wrong. I had issues with the process because I didn’t manage my time well enough so that I could constantly communicate back and forth with potential companies to procure a bid, causing me to lose bids and get no responses. I also learned the importance of time management from the failures of the final design, although I worked hard during the last few weeks leading up to the competition, I did work with the same drive for the whole marking period causing the final design to be rushed in construction causing issues with both the gear system and the waterproofing leading to the failures of each. Another thing I learned from my failures is to always keep trying and fixing your design, over a period of about three days my arm design stopped working and the waterproofing failed as well, after giving up on the arm I was I was given encouragement from my teammates and went back and tried to fix the failures to the best of my abilities.
I learned a lot by doing this project, and not just because of the failures I encountered either. One thing I learned a lot about was myself I learned how far I can push myself and how much I can handle under pressure and what attributes I have that are valuable and not so valuable. also learned a whole lot about engineering, which is good considering I might major in it. I learned about gear systems and the mechanics behind them and what allows them to function well. I also learned a lot about motors, how they worked, how much power they need, and even how some don’t need to be waterproofed if they are being used in fresh water. I learned a whole lot about wiring and motor controllers by helping my teammates with the control system. I also learned how to go through the design process from beginning to end. The process that I had to go through, although arduous and cumbersome at some points has defiantly opened my eyes up to what I will be dealing with in the real world, and how much more complicated things actually are. The final and most important thing I learned was that I do not want to be a mechanical engineer. Although I had one of the greatest experiences with this project I learned that mechanical engineering just does not suit me, mostly because of the issues I had with the construction of my design.
My final design had some significant design flaws that need to be addressed. The first is the waterproofing issue; the original concept was for the back half of the arm to be water tight because of the way the housing was put together. However I did not foresee the issues screws would cause with waterproofing, the screws did not seal the back half of the arm. Another problem with the waterproofing was the divider of the arm, this piece was also supposed to keep the back half of the arm dry, but improper cuts created a piece that did not fit snuggly in the arm. To fix these design flaws I would have either had to spend more time carefully waterproofing the arm with epoxy, or a better solution would be scraping the idea of a waterproof housing and just to waterproof the motor itself, which would mean there would be less areas that water could sneak in because the are to be waterproofed would be smaller. Another design flaw was the motor, the motor chosen was a small DC motor that ran at low voltage to save power and also low amperage, and how it ran too quickly. The motor spun the gear system too quickly for the system to function well, this flaw could have been fixed with a different motor that had a much lower rpm and a much higher torque than the motor originally selected. Another issue with the design was the gears, the gears that were used for the arm were hard plastic gears, however they were not able to be fastened easily to any rod to keep they suspended, this issue caused a discrepancy in the heights of the gears and cost numerous hours of work trying to get them close to the correct height. This flaw could have been solved by purchasing industrial gears that could be locked onto rods with a simple wrench and would stay in place much better than epoxy could ever hold the plastic gears.
This project was one of the most demanding ones I have ever undertaken and it helped improve my problem solving skills, my communication and teamwork, as well as my organizational skills. My problem solving skills were improved mightily during this project for a numerous reasons. The first was because of the design of my arm; I was tasked to design an arm that could perform three tasks within twenty minutes so right from the beginning of the project I was using my problem solving skills to try to make the design work. Another way my problem solving skills were improved was when the team was making last minute repairs to the ROV. During these repairs we were all faced with problems that had to be fixed on the fly causing us to think on our feet and solve all the issues on a tight time schedule. My communication skills improved vastly in this project. Public speaking was once a huge issue for me, but because of this project and the numerous presentations that I have been up through I have a new found confidence in public speaking almost to the point where I enjoy doing it, all thanks to lots and lots of practice. My communication skills have also improved in my drawings and designs for this project. It used to be that I never gave dimensions to drawings, but because of the project and the need for each part of the ROV to work together I dimensioned ever possible line or part of my design for my teammates, so they could understand the design better and so it could incorporate better with their designs as well. My communication through writing has also improved because of this project. The project requires you to both write in the technical style as well as a more normal style, and this change of style throughout the process kept me on the edge of my toes and kept me focused on what ever I writing was at hand. Also this project finally taught me how to cite photographs that were used in papers correctly, this is a valuable skill learned because later on in life it could end up being plagiarism if I continued to do it the incorrect way. Finally my communication between people improved as well. Working in a team forced me to communicate with them nonstop even if I didn’t want to at certain points. The project taught me how to convey my ideas and thoughts in a much more lucid manner making it easier for my teammates to understand me. This project improved my organizational skills by forcing me to plan out my work schedule months in advance and try to keep to that schedule by requiring commenting on my schedule almost daily. It also forced me to manage my time between the actual arm and the paper work and other things that were part of the class and the competition.
Overall this project was something that I enjoyed thoroughly and learned a lot from. This project pushed me very hard at points but at the same time taught me valuable life skills like better communication and organizational skills, as well as problem solving skills. I feel like I did not do as well as my design could have, and that was due to some of the design flaws as well as my laziness. If I had the chance to re do this project I would in a heart beat, because I had a lot of fun doing it as well and I learned a lot too.