Individual Reflection

The ME 250 project was a long process. From the brainstorming to the last screw, the project was stressful. This class was very helpful in understanding how an idea evolves from a thought to a physical machine that completes a task. The biggest thing that I learned from ME 250 was how to effectively manage time and money. There were only a few short weeks in which we had to take our final concept and manufacture it from scratch.

There were a few difficulties that we encountered along the way. I think that the most frustrating part of the project was the inconsistencies throughout the semester. Not only were there multiple MAJOR rule changes, but there was also a lack of enforcement of these rules during the day of the final competition. These rule changes did not allow us to continue the design process on one specific design. We were continually starting from square one as we were repeatedly told that our idea no longer was legal. Another struggle that we had with the course was the fact that we were a three man team. I know this is not the fault of anyone of the course leaders, but the absence of a fourth member made the entire project very stressful on the three of us. We were responsible for picking up the work load and this often meant missing other lectures or spending extra hours in the shop. I personally also had trouble with the analysis of the manufacturing. I have been in a shop before, but had never been accountable for the selection of materials of the testing of those materials. This class taught me how to choose materials and machine those materials based on specific guidelines and regulations. I found it very useful in this course to learn about the engineering behind manufacturing and the physics which are used during the design and manufacturing process.

If I were to change something about this course I would recommend that the slotbots game not be so sophisticated. The game was very complicated with a lot of rules. These complications led to many teams not even being able to score one ball come competition day. Also I would be much more strict in enforcing the rules that are finalized. There were many robots in this semester that did not follow the rules on competition day and should have been "eliminated after the first round of competition" yet somehow they were able to continue and in one case even win a substantial amount of money. One last thing that I would consider when designing next years course is more manufacturing time. The learning of mechanical essentials is vital for the course, but I believe that many teams would have been able to design and build more effective robots with two more weeks of manufacturing time.

I am very proud of the work that my team submitted. If i were to find an area that we could improve on it would be practice. Had we been able to complete our robot in a shorter period of time we would have been able to practice driving it and would have been more effective in the competition. Overall I think ME 250 is a great course and could become an excellent course with minor adjustments.

Final Machine

Our machine has evolved significantly as the semester has gone on...

Slot module
This module uses paddles powered by planetary motors to move balls toward the flipper and under the wedge. The current design has the motors mounted on top of a wooden frame which hangs from the table in the slot. These motors drive belts which turn paddles mounted on a rigid axle near the bottom of the starting zone. The paddles are at right angles and are different lengths to conform to the slot starting zone.

Compare this design to our original idea of a slot-mounted aluminum frame. Changes in the design were a result of budget constraints and rule clarifications.

Wedge Module
The wedge remains largely unchanged from the initial stages. It still has the same function: block the flipper and let balls under to our bin. The first main difference is the notches in the lower part of the wedge, which keep the wedge in, should the bumper be pushed from the other side. The second difference is the brass tips on the wedge, which create a denser lower half, keeping the wedge oriented vertically as it falls. The third difference is the pair of notches used in conjunction with the release mechanism to make a clean release. These changes are a result of tests and design insights.

The original model was a solid piece of aluminum, which would have been difficult to make and ineffective in play.
Top Bot

The top bot remains almost completely unchanged, and is our best-designed and most robust module. It is used to displace balls defensively and can collect them as a backup offensive measure. Any changes in the design were minor and took place early in the process.


It has been a long, frustrating, busy, FUN semester!!!! We learned a lot and built a functional robot... gearing up for 350 next semester

Last sign off,

-Team MA

Stephen Lanham: Individual Reflection

This ME250 class was like nothing I’d experienced before. Coming in to the class, I had never used any CAD software or set foot in a machine shop. Needless to say, I learned many new skills in this class, all of which will help me throughout the rest of my engineering career. The experiences I had while familiarizing myself with these fundamentals of engineering resulted in a very positive experience overall.

The first learning curve I encountered was sharp: having never used any program remotely similar to Solidworks, I was very lost during the first few lab sections. I found myself having difficulty translating the ideas in my head into geometry and constraints on the computer. However, after taking some extra time to fiddle with the program, I quickly discovered just how intuitive Solidworks really is. I can recall a specific instance, in fact, when everything clicked. From there, it was just a matter of figuring out the depth of the program. Of course my future engineering applications will not all use Solidworks, but in a field that is becoming more dependent on computers by the day, even this small introduction to CAD is helpful. For my next design project, I think I will better utilize the CAD program to test my design before I start manufacturing. My use of it this year was mostly restricted to creating drawings for the shop, but I have learned that it is better to use the computer to model than to have to build, redesign, and build again.

Machining was something I also hadn’t done, so I wasn’t sure of what to expect. It turns out that I enjoyed manufacturing more than CAD modeling, but it also offered many, many more headaches. I have always liked to work with my hands, especially with wood, but this class exposed me to a whole new level of machining. Precision, tolerances, tools, tool and feed speed… I learned that in the machine shop, you have to account for all of these factors and more in order to get the piece you want. I also learned that if multiple parties were designing and manufacturing, ideas had to be laid out completely explicitly in drawings, or they would certainly be interpreted incorrectly. If there are limits on materials or time (which there always are), this creates a serious issue. In the future, I need to remember to devote more time than is necessary to the machining of parts. It was frustrating to be making a part on a tight time limit, something which never turns out well.

Although I have worked in teams before, this class presented a special challenge. The combination of all the stress, the crazy travelling schedule our group had this fall, and only having three team members made this a uniquely difficult class. Luckily, all members of our team were involved and dedicated to success. This created an environment where we consciously let our strengths compliments each other’s, and strived to hit all goals efficiently. Being explicit when communicating ideas was a struggle at the beginning, but we learned and adapted as the class went on. This class has convinced me that on future projects, I should designate stronger team roles and more rigid schedules at the beginning of the process, so that there is limited confusion in the end.

I do have a few suggestions for next year’s class. My primary issue is that although the staff were clear on the goals of the class, they were not always clear to the students about what exactly was expected, what was an acceptable manner of achieving our goals, and what we could expect from them as the facilitators of the class. The several rule changes throughout, a solid model that did not reflect the true dimensions of the arena, and subjective differences between the lecturers and GSI’s all made for a very confusing design process. These issues did not create an insurmountable goal for the teams, as all of these problems can be easily solved, but a little more organization would have been nice, especially because that is what is expected from the students. I suggest perhaps simplifying the game for next year, so that it is not necessary to put so many constraints on the rules. Otherwise, the class was run in a fun and interesting manner, and was a GREAT experience overall.

Final Bill of Materials

Our final Bill of Materials can be found here:

https://spreadsheets.google.com/ccc?key=0AnEPq3yyX7WTdHZaVUZKRXVjREJ2LUREM0U1QllqbWc&hl=en&pli=1#gid=0

The parts that we purchased are highlighted in the Bill of Materials, but are explicitly listed here for convenience:

https://spreadsheets.google.com/ccc?key=0AnEPq3yyX7WTdHhVMUFDc1BDMGtpYzZiUDllS3dPSEE&authkey=CNHw4HU&hl=en#gid=0

Josh Getz: Individual Reflection

ME 250 was a class that certainly required a lot of time and effort. The course aims to have students learn the basic concepts of design and manufacturing, and then apply them to create a working robot that plays a game that we all know and love, Slotbots.

I had never really “formally” made anything. Meaning that I’ve certainly built my fair share of things, but I’ve never gone through the engineering process the way we did in this class. I’ve learned that when faced with a daunting task or given a large project, the first thing to do is step back, and look at the whole picture, and break the problem down. Ask what are we trying to do, and what are the parameters that need to be met? Then continue on to ask how are we going to do this? This is followed by brainstorming and the selection of a concept. Essentially I’ve learned the value of the funnel that Professor Hart talked about in lecture. Start big with strategies, and then work your way down to small components, and how all the pieces interact with each other. The amount of detail, and the importance of selecting the correct tolerances and materials was often the difference between success and failure of the robots that were built. The effort spent keeping drawings and CAD models up to date, and accurate down to the washer may take longer initially, but it saves hours of time spent remaking parts that were made incorrectly because of an unclear or mislabeled drawing. The knowledge of what each tool can do, and how to use them properly will not only allow for a better part to be made, but you will learn more about what the best way to go about making the part is. The most important things I’ve learned about design and manufacturing are the need for accurate drawings, and a full plan of action before diving into a project as it will save time, money, and result in a higher quality, better overall product.

Building a slotbot is certainly not a one-man job given the time frame. Members of teams needed to depend on each other in order to be successful. It is important for all members of a team to fully understand the project, but they do not have to be an expert in every aspect of the project. The key to a successful team is leadership, and dedication of the members. The leader needs to recognize the skills of the members and utilize them to their maximum potential. The leader also needs to keep everyone on the same page, working together towards a common goal, as well as keep the team to a schedule. The schedule may need to be constantly updated, but it is important to know what has to be done when, and how much time can be allotted to different tasks. Members must be able to trust the work of other members, which requires the dedication of every member. It is also important, especially in the design stages, that nobody is scared to say what is on their mind, even if they think it isn’t a good idea. When a member is struggling with a task, the other members need to step in and help.

I believe my performance could have been better if I was slightly more on top of the material. I was so eager just to build, that I didn’t take enough time to really learn and apply the design concepts from lecture. Despite this, all of our modules were functional, and well constructed. The fundamental problem in our design was the robustness of our two modules that were in the slot. We relied on gravity to deploy our wedge, which, once in place permanently locked the flipper in our favor. However it was difficult consistently get it to fall into the correct place. It would have been a much smarter idea to use a giant hollow wedge that extended all the way up the slot, as several other teams had. The primary reason in our poor performance in the competition was more a result of lack of practice operating our modules, as all our modules functioned as they should (outside of the wedge deployment). Another thing that I could have improved was the schedule. We loosely stuck to the schedule, and seldom updated it. We got everything done on time, but at times it was slightly unorganized resulting in inefficient use of time.

This course was quite frustrating overall. Frustrations began with the rule changes. I was part of a three member team, so we were already pressed for time, and literally every rule change required that we completely redesign at least one module of our slotbot, nullifying hours of CAD, sketching, and brainstorming. It wouldn’t have been such a big deal, however there were at least three rule changes that were in no way a “clarification” after the rules were supposedly set in stone; the biggest of which were the constant starting zone adjustments and the new last minute ball configuration. What angered me even further was the fact that hardly any rules were actually enforced during the competition. Nearly every team was outside of the starting zone “The zone measures 24" along the slot (starting at the edge of the ball retainer) and 24" perpendicular to the slot.” Rule C-1. But an even bigger issue was the fact that the team that got second place did not meet the size requirements of the robot as stated in the rules “Your entire machine must fit in a box no larger than 12" x 12" x 24", and yet somehow they walked away with $200 despite rule B-3 which explicitly states “Machines that exceed the size and/or weight constraints must compete, but are not allowed to win.” I don’t know why it was decided that the rules would not be enforced but it was certainly not a fair competition in any way. There were far more rules that were violated by many teams that I don’t want to go into now, but I am disappointed in the standard withheld in the competition. Despite the lack of rule enforcement, I did learn a lot in the class, and I think that this version of ME 250 is a great class. I would recommend either changing the rules to those that can/will actually be enforced, or making the game a little simpler. The game this year was far more complex that it was last year, which is why so many teams failed. Another suggestion would be to give teams perhaps a week or two more manufacturing time, which will allow for more design flaws to be worked out and hopefully result in a more successful competition.

Overall I enjoyed this class. It was very interesting and fun to see an idea come all the way into full functionality in just a few short weeks. I am looking forward to 350 in hopes to apply what I’ve learned from this class, and improve in my performance.

Check out the team video

Enjoy

-Team MA

MS9 complete!!!

After some hustle and bustle on Friday night and some modification over the weekend, all of our modules are functional and ready to go for MS9. The functionality of each module is good, however there are still tweaks to be made in the slot module and the wedge.

Issue #1: Unfortunately, due to the fact that when we originally tested the wedge, the weight on the flipper was not accurate, the wedge is not sliding down into place like we had hoped. However the firing mechanism is functional.

Issue#2: The flippers tend to run at slightly different speeds, causing them to come into contact with each other. There is team discrepancy over the way we should handle this. It may be the best to trim the paddles, seeing as we don't need to focus on the squash balls.

However, we have Monday and Tuesday to deal with these problems, which should be within the scope of what we need to do.

Pushing it to the wire,

-Team MA

The Home Stretch

T-minus 8 days! All of the manufacturing is due next Tuesday, which means that we have 6 days of manufacturing time left! We will have to be efficient with the time that we do have, but we should be able to finish with a comfortable window of time left. We need to focus on milling a few parts for the top bot, and need to mill all of the parts for the wedge launcher, and then the final assembly begins.

Currently, we need to fasten all of the fixtures to the top bot body: the casters, the pillow blocks and the motors all need to bolt to the bottom. We also will need to fix the inner walls to collect the balls, and the arm which sweeps them into the body.

In addition to this, we were unfortunately the victims of a late-shipped order of screws from McMaster-Carr, which means we have to devote about an hour of this week to assembling our slot module, which should have been done last week. However, this does not require shop time and can likely be done in lab section.

Construction of the wedge launcher will begin this week, and requires us to mill four parts and lathe two axles. Luckily, if things run smoothly, this should not take up more than four hours of our shop time.

Lastly, the electrical wiring and tether for the top bot will need to be constructed. This is a unique design, something that we will have to think twice about before implicating, but will not take place until the end of the week.

We begin our busy week with 8 days left!

-Team MA

Pre-Thanksgiving Crunch Update

Due to rounds of exams for all members of Team MA, there was a lull of sorts in production over the last week. However, we now have several exams under our belts and are ready to be back in action in the shop this week. Having destroyed Ohio State in Columbus yesterday, we are fired up and ready to finish up the fabrication for the MCM, which according to the original schedule is due Wednesday. We will be taking today to prepare for what needs to be done so that our slot module is in working order by the due date. It comes down to us milling a couple more parts, turning the axles, and fitting everything together. This shouldn't be a problem for us to complete on time.

Once the slot module is done, there are a few things to be done for the top module and wedge module, but they are relatively simple. Soon we will be able to test on all our modules and will have a few days to change them, if needed.

We will update when the slot module is complete! Until then,

Team MA

A good week!

Some good news from Team MA!

The wedge is DONE. And better still, it works well. After some testing and revision, the wedge slides easily into place, admits balls, and stays there.

The CAD is (very nearly) DONE. Three of our most critical modules (wedge, slot, topbot) are 100% modeled, but we are still making revisions to the design of our fourth module. We do not anticipate construction on this module to be complex or time intensive. However, when we're not in the lab, this will receive most of our attention in group meetings, which means it should be completely modeled by the end of the week.

Fabrication is also going well. We cut most of the body parts of the topbot, laser-cut the paddles, milled the sleeves, and cut and milled the axle mounts. The next step is to laser-cut the slot bracket parts, and water-jet the metal slot components and the topbot body. This should be completed by Tuesday, then we can drill the necessary holes in these parts, turn the axles, and begin assembly on all of our modules.

The team is optimistic about being able to finish preliminary fabrication with plenty of time to test, practice, and revise our design!

-Team MA

Budget Woes

The team met tonight to discuss the work ahead of us this week. After taking a second look at our budget for the project, we realized that even with our recent redesigns, our design put the budget for extra parts a whopping $60 over the allowed $100. To fix this, we made some necessary sacrifices in performance to accommodate cheaper parts. Primarily, we switched out the bearings on the top bot for bushings. This is obviously the less efficient choice for this design, but cut over $20 from what we would have to spend on bearings. We also had to take a second look at our bracket, which if we choose to make out of 1/4'' aluminum, would cost half of the available $100. We decided instead to use a combination of the 1/16'' aluminum, 1/4'' wood, and 1/4'' aluminum given to us in the kit to make a bracket that is both cheap and strong enough to do what we need it to do.

We plan on starting construction of the paddles, bracket, wedge, and top bot plate on Tuesday. If things go smoothly in the lab, we should be able to mostly, if not fully, complete all of these components. Many of our other components cannot be started until we receive the parts from McMaster-Carr and other product dealers, which were ordered tonight. We anticipate these arriving at the end of this week, allowing us to complete the slot module and the wedge module by early next week, with the top bot not far behind.

Looking forward to getting started on manufacturing!

-Team MA

MS6: Most Critical Module

Last night, the team met to complete all engineering on our most critical module, in order to be prepared for today's meeting with Davor. The meeting was productive and enlightening, but the team encountered some obstacles along the way:

While composing the bill of materials, we realized that, though using a solid aluminum plate would certainly be the most robust design for our slot brackets, the supplies required are far beyond our budget. Unless we wanted to be $200 in the red, violating the rules, and draining our bank accounts, we had to change something. We could either change the design or the materials used in the bracket. Unfortunately, plastics, the cheapest option for what we need, are typically not very good for structural purposes. Therefore, we changed the design of the bracket, keeping only the members which were absolutely necessary to the design. In order to be efficient with our use of materials, we also had to change the design to be composed of several small parts. This increases manufacturing time, but is not a significant issue.


On a better note, after a helpful and successful meeting with Davor, we are fully on track to begin production of the slot module next week, directly after the production of the wedge. This weekend will be spent finalizing the engineering for the top bot and the wedge launcher.

We are staying busy... which means we're on schedule!

Until next time,

-Team MA

Progress Update #1: Engineering Drawings

We can see the light at the end of the (first) tunnel!

Team Mechanical Advantage is almost at the end of the design phase! Currently, we are working on producing drawings for our modules so that we can get into the shop next week and start manufacturing. We have already fully completed the drawings for the wedge module, and will be finalizing those for the bracket/slot modules tomorrow night. Because these three modules are so interconnected, we have yet to decide what is our "Most Critical Module". Unfortunately, additional rule changes forced us to redesign our slot module (again), putting us one or two days behind schedule with our CAD. Luckily, we are still comfortable on time, even with this setback. The top bot drawings are relatively simple, and should be completed by early next week. We have also been busy creating parts lists and deciding which components to buy from McMaster-Carr.

As we complete drawings and solid models in the next few days, sample pictures and drawings will be posted on the blog! Fabricating and testing of the wedge will also commence next week, to ensure that everything is going smoothly.


-Team MA

Team Design Schedule 2010

Here is the link to the schedule for Team Mechanical Advantage:

       https://spreadsheets.google.com/ccc?key=tTuLDz1asOLPUW363x7RXrw&authkey=CNLjqp4B&hl=en&authkey=CNLjqp4B#gid=0


A note about this schedule: All entries and deadlines indicated on the schedule are the absolute last date by which a certain task must be completed, whether the deadline is enforced by the class schedule or not. The schedule may be moved forward or changed subtly, depending on the progress of the team.

-Team MA

Strategy and Concept Summaries

       The strategy that we chose to play SlotBots focuses on a two-part approach: offensive maneuvers in the slot and defensive maneuvers on the tabletop. We selected this strategy because we thought it would be a successful hybrid of two separate approaches to the game. It has the most comprehensive defense against a variety of opposing ideas we might encounter.

       The concept we thought would best implement this strategy consists of three main modules. The first is a wedge which will be dropped into place at the beginning of the round, securing the bumper in the open position for our team, while preventing our opponents from scoring in the slot. The second module is the main offensive module; a system of motorized paddles mounts to the walls of the slot to shuffle balls through the wedge and into our bin. The third module is a tabletop bot whose primary objective is to displace balls on the tabletop, preventing the opponent from scoring them. Though it is primarily to be used as a defensive measure, the tabletop bot can also collect balls and score these as a backup offensive measure.


More pictures will be made available through the blog as the team finalizes the solid models and prepares for the fabrication and testing phase of the project.

-Team MA