MRDC Resources

A brief guide for first-time MRDC Captains. Once you have been elected as the freshman MRDC captain as a part of iRobotics, use this guide to get moving.

Startup Checklist

This checklist should be completed in the first semester. These are essential to a team successfully completing their build in the spring semester. Note that some of these items are not immediately available at the start of the semester, check in continuously with the executive board to determine when you can complete objectives.

1. Register a new RSO
   1. Sign up with CollegiateLink
   2. Click "Register a new RSO" or similar
   3. Submit initial registration attempt ( it will be denied)
   4. President takes "President's quiz" and "Food Safety quiz" in compass2g
   5. Treasurer takes "Treasurer's quiz", "Food Safety quiz, and "SORF quiz" in compass2g
   6. Resubmit registration attempt (it should be accepted)
   7. President, Treasurer, and Authorized Agents accept invitation via email and log into Collegiatelink to accept there alos
2. ESPL access test (Captain and a few other memebers)
   1. Complete DRS online training (general lab safety)
   2. Be added to the ESPL roster
   3. Register for ESPL 100 on CBTF ( Computer Based Testing Facility)
   4. Sign up for ESPL 100 test slot
   5. When you get in the test center, click “ESPL Access Test”
   6. Pass test with at least 89%
3. Machine shop access test ( At least one person)
   1. Sign up for ESPL 100 test slot
   2. Review documentation and study for exam
   3. When you get in the test center, click “Machine Shop Access Test”
   4. Pass test with at least 89%
4. Welding Access Test (At least one person)
   1. Sign up for ESPL 100 test slot
   2. Review documentation and study for exam
   3. When you get in the test center, click “Welding Access Test”
   4. Pass test with at least 89%
5. Machine shop initial part training (At least one person)
   1. After getting email from Bruce confirming access, sign up on spreadsheet for at least two 2-hour timeslots (4 hours altogether)
   2. Do initial part training with Dave

It is recommended for MRDC that at three people get card access in the fall semester to the building. Of those three, at least one should have completed all of the machine shop training, and someone else should have completed welding training. More people trained is always better, this is the minimum. Welding training only required if you wish to build a welded-tube frame.

Design around the game

First and foremost, MRDC is an objective based game, and you are building a robot to complete the required tasks in order to score points. This necessitates that all design choices on the robot should be made in context of "how many points will this help us score?". Discussions should remain framed around point scoring and opportunity cost. Below we have included a short step by step design guide, and you should follow it after a rough fashion. Please note that many of these tasks will require revision, so don't be afraid to go back a few steps and cycle around.

1. Meet with team and go over the rule set in detail
   1. Identify which point avenues get you the most points
   2. Crosscheck with how difficult an avenue is to complete
   3. Rank avenues by points accrued per amount of effort expended, keeping in mind how difficult each task would be to design a manipulator for
2. With your ranked avenues, brainstorm manipulators to fill each task
3. Assign manipulators to each task, think about interoperability and the overall robot
   1. Consider how you power each manipulator. Are you using motors, pnuematics, linear actuators?
   2. Arms are the manipulator of last resort
      1. They may seem easy to conceptulize, but they are extremely hard to design, power and control. Often they are the first thing thought of during brainstroming sessions, they should be the last thing taken seriously. Even in best case scenarios, an arm will be substantially outperformed by a custom manipulators. You should only choose an arm if the game requires it. Reach out to other MRDC captains if you can not figure out something better than an arm.
4. Tour your ESPL space and make note of what components you already have
   1. You are working on a very limited budget, heavily favor manipulators and components that you already own over ones that you must purchase
   2. We have been building MRDC robots for years, ask other captains if they have spare parts before you go out and buy your own.
5. Pick a reasonable number of manipulators to complete desired tasks, lean heavily on the KISS principle.
   1. Consider the M.V.P (Minimum Viable Product) principle many startups use to build successful products. Basically the idea is to choose the most simple product that will do and design that first. You should apply this to your robot design as well. Becoming overly consumed with the efficiency or speed of your robot is meaningless if your manipulator never works in the first place. In MRDC generally the robot that wins is fairly simple, but it works reliably.
6. Pick a Drive Train
   1. Keep in mind that you only need it to complete the required tasks, and fend off other robots
   2. Don't make it overly complicated, since this cuts into manipulator design and build time.
7. Pick a frame construction technique
   1. There are tradeoffs with each frame type, though welded tube has been preferred as of late
   2. Remember that different frames require different tooling, you must have your machinists trained ahead of time if you wish to build certain kinds of frames
8. Roughly lay out manipulators and drive train
   1. Create some rough sketches of your frame to hold these components
   2. Don't forget to leave some space for electronics.
9. Have a design review with the MRDC Captains
   1. They will provide feedback on feasibility of your basic ideas
   2. Get tips on design of your manipulators, frame thicknesses, parts, and drive train choices

Picking electronics

Picking electronics is all about building the most effective solution to power and control your manipulators, with the least amount of cost and hassle. It is key to not overcomplicate! This should be true of everything that you build in MRDC, but there is a particular allure to choose overly complex solutions with the electronics. For instance, you only need motors big enough to do the job, you only need speed controllers big enough to power the motors, and you only need a micro-controller powerful enough to put out some PWM signals and receive radio signals. While a lot of this design is dependent on the mechanical components, it does not mean you cannot start designing early by making educated guesses and getting difficult things like wireless working.

1. Identify all the motors and electronics you need to work. Once that is done you can draw up an electronics schematic and do some simple back of the envelop calculations to pick other electronics.
   1. Drivetrain
      1. Brushed: Good idea if this is your first robot as a team. Something like a CIM motor from Andymark is a good idea . It comes with a large number of gearbox options, and has many helpful tips from its ubiquity on in the FIRST competitions. There are also many tried and true ESC options, the motors cheaper, and controlling them is simpler. Other offerings can be found from companies like Ampflow, though these come at an additional cost.
      2. Brushless: For when you just gotta get that power, or you need to save weight. Using 1/8th scale RC car motors, iRobotics has managed to jam 2100W motors with a gearbox into the weight of a CIM motor. However many of these motors can be less than reliable, and come at a significantly higher cost. Your team will also have to be much more careful with maintenance and design to pack that much power under the hood. Read some of the older build guides before you attempt to use these.
      3. Speed Controllers:
   2. Pneumatic System
      1. Compressor
      2. Servo
   3. Manipulator Motors
   4. Manipulator Servos
   5. Steppers and Whatnot