Robot Building & Programming September 4, 2018

What can I use to build my robot? Read the Robot Game Rules! Past rules stated: Everything you compete with must be made of LEGO elements in original factory condition, except LEGO string and tubing, which you may cut to length. Exception: You can reference a paper list to keep track of programs and a bin to carry your robot. There are no restrictions on the quantities or sources of non‐electric LEGO elements, except that factory‐made wind‐up/pull‐back “motors” are not allowed. Pneumatic elements are allowed. Marker may be used for owner identification in hidden areas only. Paint, tape, glue, oil, etc. are not allowed.

What can I use to build my robot? The electric elements used must be the LEGO MINDSTORMS type, and the total number of electric elements you may use in one match is limited as follows: One Controller (RCX, NXT, or EV3) Four Motors Must be Mindstorm Motors A fifth motor is not permitted in the competition area (you may have spares at the pit) Unlimited Sensors but must be Touch, Light, Color, Rotation, Ultrasonic, or Gyro Must be LEGO manufactured MINDSTORM sensors Read the Robot Game Rules!

Where to Start? If you have a first year team, the best option is to build the Mindstorm kit robot.

Common Attributes of FLL Robots Two motors used for the drive wheels (usually one for each side) The third and fourth motor for some sort of vertical lift or arm mechanism Different missions may require different attachments It needs to fit inside the home base (including 12” height!)

Mechanical Design

Mechanical Design: Durability Evidence of structural integrity; ability to withstand rigors of competition Goal: rare faults/repairs Things to ask yourself about your robot Does it stay together through routine handling? Does it flex too much when moving? Will my wheels touch the ground?

Mechanical Design: Durability Evidence of structural integrity; ability to withstand rigors of competition Goal: rare faults/repairs Proper mounting the Drive motors to each other with a sturdy frame is the key to having a solid robot. Less likely to fall apart Better (and more consistent) movements

Mechanical Design: Mechanical Efficiency Economic use of parts and time; easy to repair and modify Goal: appropriate use of parts and time to repair/modify Things to ask yourself about your robot Can I change the batteries easily? Can I see the video screen and push the buttons? Can I plug/unplug wires easily? Are the wires in the way? Can attachments be changed easily? How long does it take to set up my robot in base?

Mechanical Design: Mechanical Efficiency Economic use of parts and time; easy to repair and modify Goal: appropriate use of parts and time to repair/modify About Attachments Different missions may require different attachments (worth saying twice) Some attachments may remain on the robot, while others are swapped out Exchanging attachments should be quick and easy Consider using LEGO magnets from the LEGO train sets (www.bricklink.com is a potential source)

Mechanical Design: Mechanical Efficiency Economic use of parts and time; easy to repair and modify Goal: appropriate use of parts and time to repair/modify Robot Setup – Know Where to Start! The starting square is big, where does the robot go? When positioning the robot, the angle the robot is heading is very important. If the heading is off by 1 degree, four feet from the start the robot will be off course by over 1 ½ inches Even robots that self correct position need to have a consistent starting point Proper starting also includes powered arms and other attachments Alignment tools help if built properly

Mechanical Design: Mechanization Ability of robot mechanisms to move or act with appropriate speed, strength and accuracy for intended tasks (propulsion and execution) Goal: appropriate balance of speed, strength and accuracy on most tasks Things to ask yourself about your robot Am I using the right wheels? Big wheels are faster, can move over obstacles, but are less accurate. Wider tires have more friction than skinny tires making turning less repeatable Am I starting, stopping, or moving too fast? Do the wheels spin or skid? Where is my center of gravity? How will it change when I pick up loads? Am I top heavy? What happens when I back up?

Mechanical Design: Mechanization Ability of robot mechanisms to move or act with appropriate speed, strength and accuracy for intended tasks (propulsion and execution) Goal: appropriate balance of speed, strength and accuracy on most tasks Will gears help? About Gears… Little Gear on Motor and Big Gear on Attachment or Wheel Slower More Precise More Torque Big Gear on Motor and Little Gear on Attachment or Wheel Faster Less Precise Less Torque

Mechanical Design: Additional Considerations Building should take into account what the robot needs to do. How do I correct my position? Which way is forward? Am I using the default ports for my drive motors (for NXT and EV3 should be B and C)?

Mechanical Design: Additional Considerations Notes on Alignment Tools: Align with solid edges of robot, not by sight Provide 3 points of contact to get both angle & front/back position correct Alignment tool can't interfere with robot as it begins to move Don't rely on table border, since there's a variable space between edge of square and table rails

Programming

Programming: Programming Quality Programs are appropriate for the intended purpose and would achieve consistent results, assuming no mechanical faults Goal: should achieve purpose repeatedly Use sensors for accuracy Know the starting location for each mission. Make sure you can quickly place the robot its proper starting position – many teams build a starting jig.

Programming: Programming Efficiency Programs are modular, streamlined, and understandable Goal: appropriate code and easy to understand I want to see Comments Comments Comments Create MyBlocks for code that is used more than once. Create MyBlocks to encapsulate blocks of complex code Give your programs meaningful names Bring printouts of your code to the robot judging session!!!

Programming: Automation/Navigation Ability of the robot to move or act as intended using mechanical and/or sensor feedback (with minimal reliance on driver intervention and/or program timing) Goal: robot moves/acts as intended repeatedly w/ occasional driver intervention Always use number of rotations for motor moves instead of time. The motor speed varies with the charge on the battery. Use sensors for accuracy Use the light sensor to line up on lines Use touch sensors to line up with objects (or the table) Use ultrasonic sensor to measure distance from objects (or the table) Use gyro sensors to make accurate turns

Programming: Automation/Navigation Ability of the robot to move or act as intended using mechanical and/or sensor feedback (with minimal reliance on driver intervention and/or program timing) Goal: robot moves/acts as intended repeatedly w/ occasional driver intervention You don’t need to use sensors all of the time. Program the number of rotations that you want the motor to execute to get close, then use a sensor to get to a specific location. Program the robot to get back to base too Walls and mission components can help line up your robot Remember to watch your speed

Strategy and Innovation

Strategy and Innovation: Design Process Ability to develop and explain improvement cycles where alternatives are considered and narrowed, selections tested, designs improved (applies to programming as well as mechanical design) Goal: systematic and well-explained Document everything you do Plan your robots features before you build. Document those features If you are deciding between two different design elements (like wheel size) document your discussion and the reasons for your decision Some teams chose between different robots. Document all of the robot designs and the reasons the robot was chosen Small changes are good. Document the reasons for your changes Keep an Engineering Notebook – good practice for FTC/FRC

Strategy and Innovation: Mission Strategy Ability to clearly define and describe the team's game strategy Goal: clear strategy to accomplish the team's well defined goals Document everything you do Plan your missions before you build or program The robot can complete multiple missions before returning to base Most missions do not require the robot to complete the mission before returning to base. In other words, the robot may start a mission and return to base before leaving to complete the mission. It’s OK to change your strategy. Just document why Read the Rules! They are vague on purpose Read the rule updates

Strategy and Innovation: Innovation Creation of new, unique, or unexpected feature(s) (e.g. designs, programs, strategies or applications) that are beneficial in performing the specified tasks Goal: original feature(s) with the potential to add significant value That said, innovation is not necessary to have a winning robot, but it sure helps Encourage creativity, but know when to stop

Show this to your students!!!! They are doing the work Finally…. Show this to your students!!!! They are doing the work