FRC 6328 Mechanical Advantage 2020 Spring Special F4 CADathon Build Thread

Hey y’all,

Hope everyone is doing well in these tough times. To get some practice for our students we’re going to give the Spring Special F4 CADathon a try and #openalliance the process.

Here’s the link to the public onshape file: Onshape

We’re also hoping to get our students a lot more active in the process of sharing information as the process is happening, so they’ll be doing most of the posting and feel free to ask as many questions as possible!


Disclaimer* We’re also going to be shifting completely from Solidworks over to Onshape, so this might be a little bumpy of a process so bear with us.


Hi everyone! I’m Maddie, a project lead, CAD/design lead, and outreach lead on 6328. Last night, our CADathon team got together to assess the game, and here are our takeaways!

In order to best evaluate the game, we sat down and worked through the Shaker Kickoff sheet last night as a few groups, the document is a condensed version of all the answers! Here’s a link to our original doc and below is all the answers, feel free to ask any questions!

FRC 2791 - Shaker Robotics

Kickoff Worksheet

The purpose of this worksheet is to identify important rules and strategies for the new season.

Make sure you answer the rules questions before you try and start on the strategy questions! Otherwise, you may think of a strategy that is illegal or miss out on a killer strategy! While this may seem time-consuming, we’re actually doing this to save time by making sure everyone thoroughly understands the rules. Remember, If we don’t do something right the first time we need to make time to do it again.

Keep in mind that while these questions cover many different parts of the game, it is not necessary to do everything to have a successful season! The jack of all trades is the master of none.


Periods of the match

  • Are there different periods in a match where the rules or point values change? Hints: autonomous; endgame
    • No auto in this game
    • Teleop - 2 minutes and 15 seconds
    • Endgame - Last 30 seconds, points don’t change

The field

  • List the zones on the field. Think about what makes each of these zones important.
      • A HUMAN PLAYER RETRIEVAL ZONE is a 53¾ in. long by 53¾ in. wide infinitely tall triangular protected zone directly in front of the HUMAN PLAYER STATION and HUMAN PLAYER CHUTE. A HUMAN PLAYER RETRIEVAL ZONE is ALLIANCE-specific and designated with the appropriate ALLIANCE color tape.
      • A WEIGHT PLATE RETRIEVAL ZONE is a 24 in. long by 36 in. wide infinitely tall triangular protected zone directly in front of the center edge of the LIMBO BARS. A WEIGHT PLATE RETRIEVAL ZONE is ALLIANCE-specific and designated with the appropriate ALLIANCE color tape.
    • LANE
      • A LANE is a 12½ ft. by 42 in. infinitely tall rectangular protected zone directly under the STATIONARY BAR. A LANE is ALLIANCE-specific and designated with the appropriate ALLIANCE color tape.
    • END ZONE
      • An END ZONE is a 48 in. wide by 42 in. long infinitely tall triangular protected zone directly in front of the FIELD GOAL. An END ZONE is ALLIANCE-specific and designated with the appropriate ALLIANCE color tape
  • What elements and features are on the field? What is the purpose of each of them?
    • Footballs - scoring through uprights
    • Weight plates - For scoring on pegs
    • Field goal - goal for footballs
    • Limbo bars - passage for robots
    • Scoring peg - weight goals and loading stations

Game pieces

  • How many different kinds of game pieces are there? What are they?
    • 2
    • Footballs (7in by 11in wilson footballs)
    • Weights (10 lbs)
  • What kind and how many game pieces can robots start the match with?
    • 1 weight plate, 3 footballs
  • Where are the rest of the game pieces at the beginning of the match?
    • At the start of the match, 6 WEIGHT PLATES are placed on each ALLIANCE’S RETRIEVAL PEG. 5 WEIGHT PLATES are available behind each ALLIANCE WALL. In addition, 4 FOOTBALLS are placed in each LANE, and 30 footballs are available in the bin behind each ALLIANCE WALL.
  • Are there any restrictions on the number of game pieces that can be possessed at once?
    • 1 weight
    • Unlimited footballs
  • Where and how do game pieces enter the field?
    • Footballs: through HP station, over alliance wall, 4/lane on the field
    • Weights: bars in the middle of the field (retrieval peg), HP loading station
  • Are game pieces returned to the game after being scored? If so, where? Which alliance has control of them?
    • Weights dont get returned as they dont leave field
    • FOOTBALLS will be placed in a BIN behind the ALLIANCE WALL by FIELD STAFF after they are scored and can be reintroduced by alliance human player

How to earn points

  • List every way to score points and their point values. Do all of them involve game pieces? Are they repeatable? Do any scoring tasks change value as they’re completed? (eg: 2017, when each additional rotor required more gears to be scored but was worth the same 40 points)? Do not dismiss any scoring method as worth too little or being too hard to think about.
Action Criteria Points
FOOTBALL scored A FOOTBALL passes between the posts of the FIELD GOAL 2 points per FOOTBALL
ENDGAME Completed ROBOT breaking the vertical plane of the tape of the ENDZONE 25 points per ROBOT
Body Builder RP Score 11 WEIGHT PLATES on the SCORING PEG 1 Ranking Point
Touchdown RP All 3 ROBOTS complete the ENDGAME 1 Ranking Point
Win the match Score more points than your OPPONENT 2 Ranking Points
Tie the match Score the same amount of points as your OPPONENT 1 Ranking Point
  • Where on the field is each kind of game piece acquired? Can game pieces be stolen from opponents?
    • Footballs from preload, in lane, or HP station, and could be stolen from ground
    • Weights from pegs and could be stolen from ground
  • Where on the field is each kind of game piece scored? Are there multiple locations or ways to score game pieces?
    • Weights are in the the WEIGHT PLATE RETRIEVAL ZONE and are scored in the ENDZONE on A SCORING PEG
    • Footballs are score through the A FIELD GOAL
  • List the heights of all locations where game pieces are scored.
    • The top of the SCORING PEG starts at a height of 42 in., and with each weight added it lowers 2 in., to a minimum of 20 in.
    • A FIELD GOAL is a 12 ft. wide by 11½ in. tall U-shaped structure in which FOOTBALLS are scored. The FIELD GOAL starts at 12 ft. wide and becomes progressively narrower by 1 ft, for each weight added to the opponent’s FIELD GOAL, to a minimum width of 1 ft.
  • List the heights associated with any other scoring tasks (such as climbing).
    • An END ZONE is a 48 in. wide by 42 in. long infinitely tall triangular protected zone directly in front of the FIELD GOAL. An END ZONE is ALLIANCE-specific and designated with the appropriate ALLIANCE color tape.
  • Are there any restrictions on where game pieces can be scored? Example: in 2018, cubes can only be scored on the scale from your null territory; in 2016, boulders can’t be shot over defenses
  • Is there any way to create closed-loop scoring, where the same game pieces can be scored repeatedly (e.g.: 469 in 2010, secret passage sniping in 2016)?
    • Doesn’t look like it

How to get penalties

  • How many types of penalties are there in the game? How much scoring has to be done to offset each kind of penalty?
Action Penalty
FOUL 5 points deducted from your score
TECH FOUL 15 points deducted from score
YELLOW CARD A warning given by the REFEREES
RED CARD The result of 2 YELLOW CARDS leading to the disqualification of a particular MATCH.
DISABLED The ROBOT will be rendered inoperable for the remainder of the MATCH.
  • List five rule violations you think will be common.
    • Pinning
    • Frame perimeter
    • In human retrieval zone G13
    • Eject game pieces from field
    • Human player sticking hands in field(lizzy rule)
  • Do any of the penalties relate to zones on the field? For a penalty to happen, which zones do which robots need to be in? In other words, can you be touching an opponent robot that is in the zone as long as you are not in the zone?
    • All protected zones, G13, need to just have a robot of the alliance breaking the plane of the zone and the opposing alliance contacting them for a foul.
  • How many opposing robots are allowed on each side of the field? Are there any restrictions on what they can do while there?
    • No robot on each side restrictions

Rank Points (RP)

  • How are ranking points earned? Are there “bonus” RP for tasks besides winning/tieing a match?
Body Builder RP Score 11 WEIGHT PLATES on the SCORING PEG 1 Ranking Point
Touchdown RP All 3 ROBOTS complete the ENDGAME 1 Ranking Point
Win the match Score more points than your OPPONENT 2 Ranking Points
Tie the match Score the same amount of points as your OPPONENT 1 Ranking Point
  • Does any RP need more than one robot to achieve (e.g. HAB RP 2019, auto/climb RP 2018)? If so, can you help those other bots in the match? Eg: Buddy climb ramps/forks in 2018.
    • Yes- endgame, lol maybe just grab them and drag their asses back to the endzone
  • How can a robot reduce their reliance on others to earn bonus RP?
    • Do weights themselves
  • Are there any “easy” ways to contribute to bonus RP?
    • Weights quick, touchdown rp
  • Do the rank points convert to point bonuses in playoffs? Eg: 4 rotors in 2017
    • No

Robot rules

  • What is the maximum legal weight of a robot? Does this include battery and bumpers?
    • 125lbs, no
  • What restrictions exist on the size of the robot and its frame perimeter? Are they different at different points during the match (or before it)?
    • Yes- 60 in starting config, can go 12 in up and 16 in out
  • What restrictions exist on extensions outside of the robot’s max dimensions or frame perimeter?
    • Frame perimeter is 120 in, 16 in outside on frame perimeter



  • Should each robot work independently to score points or are there ways they can work together? E.g. one robot scores hatches and the other scores cargo in 2019
    • One does weights, one does footballs, might make more sense to specialize and focus on one thing
  • What is the maximum possible score of a single robot excluding penalties? The maximum score of an alliance? Don’t worry about what is realistic, just what is theoretically possible.
    • Technically unlimited football points
    • 110 weight points
    • 75 endgame points
    • = ??? total points
  • Is there any advantage to completing certain tasks before others during teleop? E.g. scoring hatches early to have a choice of cargo scoring locations under defense in 2019, scoring cubes on the scale for 1 point per second of ownership before scoring 5-point vault cubes in 2018.
    • Score footballs when the goal is large enough (weights shrink the goal size)
  • Is there anything robots can do to stay out of each other’s way while acquiring game pieces? While scoring them?
    • Yes, don’t obstruct collection areas, prioritize speed, lanes
  • Are there any scoring locations that are harder to use due to driver visibility?
    • HP Station

Defense (and how to avoid it)

  • Are there any choke points in the field, where narrow spaces reduce maneuverability? E.g. between the cargo ship and rocket in 2019, between the airship and the field perimeter in 2017.
    • The limbo bar
  • Is it possible to score from any protected areas, where opponents are not allowed to touch you? E.g. shooting from the defenses in 2016
    • Yes, protected lane, and touching triangle load and scoring zone
  • Is it possible to line up and score by driving into a wall or other field element? This can make lineup faster and harder for a defender to interfere with e.g. scoring hatches your bumper toucher the rocket in 2019, scoring high goals with your bumper touching the tower in 2016
    • Your own wall
    • Opposite alliance wall
    • Human Loading Station
  • Are there any scoring locations that are particularly vulnerable to defense?
    • Endgame, getting trapped on the wrong side of the field


  • Are there any additional ways to score in the end game?
    • Aside from parking in endzone, just keep running cycles
  • Are there any additional penalties in the end game? Do any of these involve zones of the field?
    • No additional rules
  • Is it possible to play defense on endgame tasks?
    • Possible, but dangerous because of fouls and getting trapped on wrong side of the field
  • When are endgame tasks scored: upon completion, immediately after the match, when objects come to rest, or something else?
    • After match timer ends
  • When are endgame tasks allowed to be completed?
    • 30 seconds left in match

Tournament Strategy

  • How can a robot rank highly in the game?
    • Focus on high scoring game pieces(weights) so they can win and get that additional RP, always ensure everyone gets to end zone for endgame
  • What are the ranking tiebreakers?
Order Sort Criteria
1st Ranking Score
2nd Cumulative ENDGAME points
3rd Cumulative WEIGHT PLATE points
4th Cumulative FOOTBALL points
5th Random sort by FMS
  • What are the playoff match tiebreakers?
    • Unknown
  • Are there any situations where you may have to choose between a bonus ranking point and winning a qualification match?
    • Unlikely? Since tasks associate with RP points are worth the most points
  • What strategies are likely to win quals matches and/or rank highly?
    • Get all 11 plates and get 3 robots in the ENDZONE
  • What strategies are likely to win the event?
    • Likely similar to winning quals, since both RP associated tasks are worth the most points

CADathon Game Day kickoff!

During our first Zoom Meeting, we talked about the rules and came up with a priority list labeling what we thought was the highest game priority and what was not, going from most important to least important.

Pre-CADing Priorities:

  1. Drive (height included)
  2. Parking (w/ an arm)
  3. Be under 36 inches (height of lane, so we can fit under)*
  4. Weight scoring**
  5. Football scoring (shooting)
  6. Weight Ground Intake
  7. Football Ground Intake

*For the height, we knew that the limbo went down to two feet, but we decided that we didn’t want to go that low in fear of not having enough room to intake weights or footballs.

**Also if you score eleven weights on your alliance’s side of the field, then a ranking point can be earned, taking priority in this situation.


Yesterday, our team met again on zoom and decided we wanted a swerve drive for this game. A swerve drive allows our robot to move side to side quickly so we can align ourselves with the weight pegs for loading and scoring. The swerve drive module we are using is the SDS MK2 Modules.


Hey y’all! My name is Hallie (I apologize I forgot to introduce myself), I was the assembly lead for the 2020 season as a student on 6328 and I’m happy to be on chief!

The current project I’m working on is an arm so that we can park by merely breaking the plane of the Endzone, moving via a double-acting pneumatic piston/cylinder (1.5" stroke and 9/16" bore). This design was inspired by team 2791 Shaker Robotics and their control panel mechanism as it pivots back and forth.

*there can only be one photo per thread so I’ll post the arm out shortly after I make this post

I’m still working on it and fooling around with the dimensions, but I’m open to suggestions and tips on how I can make it better!


Here’s the out position!


I’ve been working on a weight manipulator mech for the past few days, and I’m proud to show y’all the first revision! It consists of two parts: one on the bottom for picking weights off of the peg, and one on the top for catching them from the HP station. The robot would drive into the peg (or HP station), and the bumpers and slot on the two plates would align it. Then, the pistons would retract and the fingers would grab the weight, and an elevator would bring the mech up. -Maddie


Hey everyone, I’m Shirish, a project lead as well as a CAD/Design lead for 6328. For the past few days, I’ve been working on an elevator design for this game. The elevator we are going with is heavily inspired by 1678’s 2015 robot, Lemon Drop.

We’ve decided on running with a two stage elevator on either side to be able to interact with the peg when it is at its maximum of 42 inches and a minimum of 20 inches. Here is a 2d sketch of what we have in mid so far:

Here are some progress pics, still lots of work to be done.


A couple of general updates (week one) on the Parking Arm:

  • Changed the piston to a 9/16" bore size and 3" throw (for a more tucked in position)
  • Moved the piston further down the base tube
  • changed some of the basic sketches to make the geometry work better (ex: plate connecting the base tube and the blue tube that extends)
  • Added bolts/nuts for mounting (mostly 10-32)
  • Added about two inches to the bottom of the base tube in hopes of getting more bumper clearance
  • Added a backplate to the top of the tube for a hard stop
  • Made and added all of the spacers for in between the tubes as well as shafts (shafts so that there would be reduced friction when rotating)
  • Created a mounting plate with custom spacers to attach to the drive train

Rotating Plate Sketch:

Arm Retracted/Out Positions (Updated):

Iso View of Piston/tube (Orange is 1" shaft in .5" ID and .625" OD bearing)

Still working on Bumper Clearance because the arm only extends about 8.5" outside of the frame perimeter which isn’t enough (should be 16") but can be fixed easily… hopefully


I’m not sure how helpful my ideas are/how much y’all are looking to figure this out on your own, but here’s my two (more than two) cents. I think the parking arm could be a lot simpler if you extend the plate you have attaching to the pneumatic cylinder, make it entirely polycarb, and add a couple spacers for rigidity instead of using box beam. You could also mount the piston on the outside of the box tubing. Also, is there any reason the elevator needs to be double sided? The game pieces are heavy, but a doublevator seems pretty overkill for a single 10 lb game piece.

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