FRC 6328 Mechanical Advantage 2020 Build Thread

Welcome to the Mechanical Advantage 2020 build thread, presented by #openalliance.

We’re super excited for the start of the 2020 build season and are looking forward to talking with all of y’all through-out the course of our build. Please feel free to ask any questions and offer any suggestions as we move throughout the course of our build season!

David

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Blog Introduction

Team 6328, Mechanical Advantage, from Littleton, MA is comprised of 43 students and 18 mentors. This will be the teams 4th season competition and the team is set out this season to double the number of banners currently hanging in the shop.

This season, 6328 will be competing at Northern CT, Carleton University in Ottawa, Canada, and Greater Boston district events. The overall team perspective is to build a simple and effective robot for our week 1 event, then add upgrades over the course of the next 4 weeks to run at Greater Boston week 5. This strategy will prevent us from over-reaching during the build season and put us in a position to put a major focus on driver practice prior to our week 1 event.

Team Structure

In order to best utilize all of our teams resources, we’ve developed a team structure to get as many students involved in the project as possible as well as utilizing the more senior students to lead the newer students. Over the summer the mentors sat down with each student to help them pick a main sub-team they would be interested in supporting as well as a secondary sub-team for when things are slow on their main sub-team. Below is the list of sub teams that have a sub-team captain and at least 3 students.

  • Electrical
  • Programming
  • Media
  • CAD/Design
  • Assembly and Purchasing
  • Manufacturing
  • Scouting Systems
  • Strategy

After developing this structure, we divided the mentors up to work with the student team leads to best keep all the students involved and drive the project.

Build Season Schedule

The team will be meeting on Monday, Tuesday, Wednesday, Thursday from 5:30P till 9:30P and 9A till 9P on Saturdays. Week 1 will be prototyping focused, week 2 and 3 will be heavily CAD driven, week 4 and 5 are manufacturing and assembly, week 6 till competition are driver practice and maintenance training as well as other event preparations.

In-between competitions, we will be meeting on the same schedule to work on secondary revisions for the robot. The hope is to win early to punch our ticket to worlds so we can start working on the Detroit revision of the robot.

#OpenAlliance
This year, 6328 is fully committed to being completely transparent throughout our entire build and competition season. We will be working to post daily updates on our blog on our website as well as in our Chief Delphi build thread.

The build thread will be the easiest way to communicate with us and ask questions, offer suggestions. We’re encouraging this communication and welcome it completely!

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Kickoff Weekend

Initial Impressions

From initial impressions Stronghold 2 looks like a fun game with some interesting design challenges! Shooting seems very similar to 2016 with the added challenge of indexing and rapidly shooting 5 balls. Ranking could be interesting this year as the RP challenges seem more difficult than previous years and climbing points could shift the outcome of many matches. Overall the team is excited for a shooting challenge. The team sat down after the initial game release on Saturday to go over all the rules and break down the points structure.

We structured the students to break up into 5 different subteams that they will stay with throughout the course of the first week for prototyping. After getting a good understanding of the rules, RP points structure, and points structure, the team decided on some high level priorities to drive our prototyping efforts.

Design Priorities

  1. Drive
  2. Shoot balls high
  3. Climb solo
  4. Climb with one partner
  5. Intake balls from the floor
  6. Intake balls from the HP station directly
  7. Wheel of doom

After we figured out these priorities, we broke up into prototyping subteams and each team was assigned a priority. We made the decision to not prototype a drivetrain and instead have the 2 of the teams focus on building a shooter, two teams work on developing and hanger, and one working on developing an intake.

Shooter

For a shooter, the prototyping subteams looked at a few teams to base their prototypes off, 228, 118, and 1717 from 2012, 2056 from 2016(specifically their hood). We believe shooting will be fairly straight forward this year and this biggest questions we will need to answer is how fast to spin the shooter wheel, which wheel to use, how much compression, and launch angle to hit our ideal shooting spots on the field. We believe it makes the most sense to try to shoot from your protected zones, the trench and up against the driver station. We made the decision to run a hooded shooter so the team got to work to develop a simple shooter prototype.

The students quickly got to work CADing up an initial design and cutting it on our router, here is a picture of the final product.

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The first revision had 4inch fairline, “marshmallow” wheels, with an inch of compression and a direct driven NEO. Below is a video of this rev;

REV 1

The next revision we threw on a 6in Colson wheel, now with two inches of compression and still direct driven at 1:1 with a NEO;

REV 2

We’re super happy with how this first revision came out, we could toss the ball about 43ft. The next step is to hard mounting the shooter, extending the hood(to add more time for the wheel to energize the ball), adding a weighted flywheel(less recovery time), shrinking to a 4in wheel(we have these two wheels,2477K37 and 2476K37 on order, pushing for 4” for packaging reasons), and keeping compression at 2in.

Climber

The team believes that climbing is both the easier extra RP and a significant source of points, especially in the early weeks (we are competing week 1). To ensure the extra RP we believe making a buddy climber to lift one robot is the most consistent option. Climbing with a partner behind the robot allows for balance with two robots by being directly in the center, and 3 if another partner can solo climb by attaching close to the center but slightly offset. To accomplish this within the extension limit we believe a system similar to the 148 2018 Robot Wrangler would work best. There are some questions about the legality of adding a velcro strap due to the new rules on major mechanism. If a strap more than a COTS piece of velcro is required this may require more work to be legal.

We believe this task will be high risk but high reward. Due to the possible points and RP, size constraints, and need to be strongly attached to the frame this mechanism is very high on our priority list. Initial prototypes and potentially Q&A clarifications will show the viability of this design.

Intake

For the intake, the prototyping team decided they wanted to mainly focus on trying to replicate 254s intake for 2017, with a roller than slides out above the frame to intake the ball over the bumper. I didn’t get a chance to take any pictures of this but will have more info in tomorrows post.

High Level Design Sketch

In order to get a quick look at packaging, some of the mentors sat down and started to draw up a simple 3D block design to get a better picture of how the robot might look. I’ve attached that picture below.

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Nice post, Dave. Thanks for sharing.

You mentioned 2056’s hood from 2016…do you happen to have any pics of that?

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Thanks Brad,

Here’s the picture we’re working off of and a link to the delphi thread with more info from @Holtzman

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Why is “intake balls” so far down your priority list?

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This list could still change based on prototyping. Shooting is higher because an intake isn’t that useful if you can’t then get rid of the balls. Climbing is higher due to the point values being higher than the amount of balls we think we can score early weeks and the possibility of an RP with a buddy climb. That being said we expect our robot to be at item 5 by our first event.

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Ahh, I personally would have put intaking higher than shooting.

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Depending on a team’s strategy and capabilities, they may choose not to shoot after autonomous.

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That’s part of why I asked, I was wondering if that was the case.

This list is in a lot of ways the order of what we plan on prototyping. If we can’t get a shooter down to the level we think is needed the intake won’t be as useful. We obviously plan to have both so the order isn’t incredibly important to us at this early stage. The logic is that if we can’t shoot the balls consistently there isn’t a huge reason to intake more.

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That’s interesting. Part of the reason we choose to put together an ordered priority list is to help us when we need to make tough decisions like cutting a mechanism when we start to run out of resources to spend on it. So in our case, we’d choose to cut the shooter over the intake, because if we can intake we can continue to move balls around and potentially pivot to a low goal scoring robot. Where as if we were to cut the intake and leave the shooter, we’d shoot three balls near the start of the match and then sit until the endgame. This is of course just one part of it and the reason I was kind of scratching my head when I initially saw your list.

Different approaches is all.

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I’ve bookmarked this thread and sent it to a few teams. I can already tell this is going to be one of the best resources for teams this season.

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Will have a bigger update tomorrow but just wanted to show the first pass at our scouting app.

Video here

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Sideways progress the last two days, planning on regrouping tonight.

# GETTING A MOVE ON – 1/8/20

Update: It’s still not a water game.

But the enthusiasm and engagement of the team seems to be at a fairly high level so far, hopefully paving the way to a good season. Right now, the whole team is working full-steam in order to create a variety of prototypes, including climbers and shooters.

Although it is the beginning of the school week, there are still a solid chunk of team members here scattered throughout the shop doing a variety of different things: prepping battery terminals, pneumatic systems, making intake/outake mechanisms, and CADing the drivetrain. We’re super happy with the current student team lead structure we have in place and this is driving the team in an efficient manner and making sure all the students are staying engaged.

Intake Updates

The roller intake group is working on an over-the-bumper intake to grab the power cells from the floor. Originally, they made a prototype that was roughly an 11.5” by 10” structure with the goal of bringing the power cell over the “bumper” which was simulated by a wooden 2” by 4”. The inspiration for this design was mainly from team 254 from the 2017 FRC game. This version proved to be able to engage with the ball easily, so the group worked to push rev 2 through and get it build. Below are some pictures and videos.

Intake Test 1

Intake Test 2

Elevator/Buddy Climber Updates

Right now the elevator/buddy climb group is designing and building two different prototypes, one for an elevator-style climber and another for a small buddy climber. For the elevator-style climber, the design loosely matches the common mechanism for the 2018 season with some modifications in terms of height and how it is driven. Theoretically, it’s going to be a three-stage elevator with two hooks on the end to hang off of the rung.

As mentioned before, we are putting effort into trying to develop a buddy climbing system that is as simple as possible. One possible idea is utilizing a piece of kitbot frame bolted onto our alliance partners. We would utilize this piece of kitbot by sliding a piece of 3×2 metal into the kitbot frame utilizing the cantilevered moment to pick up our alliance partner. Below is a video showing how exactly we’re testing this method. Still lots of questions about the legality of this subsystem but a positive result showed it may be possible.

Buddy Climb 1

Buddy Climb 2

In the first video we had the realization that the bottom of the kitbot frame was resting on a piece of the other robot and we wanted to isolate this to determine if only the 3×2 and the piece of kitbot could support the weight of the robot. Below is a video after removing the pieces that were interfering and it is just solely resting on the kitbot chassis and 3×2.

Moving forward we will be testing the complexity of a totally robot driven mechanism utilizing these designs.

Shooter Updates

The past two days have been utilized to design and build the next revision of the original shooter prototype, unfortunately due to many variables these designs did not hold up or produce good results. We are back to the drawing board to try to design a hooded shooter prototype that we can easily change gear ratios, number of motors, compression on the ball, and type of wheels. Below is a video of a 4 in fairline Mashmallow wheel shooting a power cell 47ft utilizing two direct driven NEO with 3.5 inches of compression.

Video

Ready for the next revision of the prototype shooter

Battery Testing

Over the course of the last three years we have been purchasing and using batteries without putting much thought into the batteries preforming at the maximum capacity. Big thanks to FRC 2791, Shaker Robotics for letting us steal their battery testing and deep cycling setup for the week so we can get the most out of all our batteries this season!

One of the other mentors who knows more about how this works will pop in our build thread on Chief Delphi and answer any questions!

Rest of the week

During the rest of the week the team will start to put together a prototype hopper/ball transportation system. On top of this, we’re going to work to put together a better design requirements sheet for both our week 1 and our week 5 events with goals and detailed plans on how to achieve all of these goals. More updates tomorrow morning!

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The smile on the students face in intake video 1 made my day. Great stuff

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best part of my week

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Keep safety in mind when spinning up these wheels. I noticed in the video the level of expansion in the wheel, coupled with the student sitting in-plane with the wheel, which seemed decently unsafe.

We use safety wire on our Fairlane wheels to prevent delamination of the wheel from the hub, and possibly even worse failures. Details here: Flywheel Do's and Don'ts

Best,

-Mike

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Thanks for sending that over, will check out that link and share it with the students. Priority for the next prototype is to be significantly safer as we discussed this after concluding testing last night. Easy to get caught up in the prototyping and just say send it, but safety should be the priority over everything.

As a small little project a few of the students decided that wanted to interview some of 6328’s newest mentors, check it out!

NEW 6328 MENTOR INTERVIEWS

Build Season Blog

Today we decided to do interviews on some of the new mentors for the team, asking them some questions having to do with their FIRST beginnings in mentoring and being on a team.

Andrew Colletta

  • Saw that we were looking for mentors and decided to join
  • Computer Science Major, Boston University, 2019
  • Part of FIRST since 2008 on team 2102 Paradox
    • Worked on machining, CAD, became the engineering president, and was the safety captain
  • Designs motion control systems at Performance Motion Devices
  • Comment about team 6328: “You guys are a really interesting team, and I like that the team is student-driven”

*editors notes, Andrew joined 6328 about an hour prior to this interview, welcome aboard Andrew!

Noah Page

  • Joined Shaker Robotics as a freshman
  • Electrical Engineering major, 2023, WPI
  • Looked up to his mentor Cam
  • Cam called him asking if he was interested in mentoring a FIRST team
  • Comment about team 6328: “Uhhhhhhh”

Julianna Ziegler

  • Mechanical Design Engineering, 2023, WPI
  • Joined team 2168 in 2017
    • Became the co-captain of the mechanical team
  • Looked up to her mentor Josh Miller
  • Comment about team 6328: “They’re so cute”

Dave Powers

  • Management and Mechanical Engineering Major, 2020, WPI
  • Started mentoring for 6328 in April of 2019
  • Joined team 228 Gus Robotics in 1998 after his dad started the team
  • Works at ETM Manufacturing as a Manufacturing Engineer
    • Decided to be an engineer at 6 years old after meeting Dr. Flush, who made an omnidirectional robot that looked like a traffic cone and let him drive it in front of people
  • When asked who his favorite mentor is: “It’s Dee, I feel like that’s a safe answer.”
  • Comment about team 6328: “The students are my favorite part.”
    • When asked about his least favorite part of being on team 6328, Dave then responded with: “The students, next question.”
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