FRC 4481 Team Rembrandts 2020 Build Thread

2020 KICK OFF
Here is a recap of our kick off weekend: https://www.youtube.com/watch?v=hzdC4WECQsI&t=

General design approach
We’ll receive our KOP on Thursday, hence why we’re taking a more detailed approach for week 1. We’re not making any strategic design decisions throughout the build season, only getting rid of absurd ideas like triple climbing. The eventual goal is to end up with a hybrid robot at the end of world championship. We won’t reach the full hybrid, heavy cycle robot in just 4-5 weeks.

To make sure we show up well prepared to our heavily stacked week 1 regional we’re aiming at robust consistent robot which has had plenty of practice time at home. While practicing working on upgrades and fine tuning sub systems and if they’re completely ready before week 1 they could be added.

The design strategy for this season will be to only put the drivetrain electronics, pdp, vrm, pcm, roborio, battery and compressor if needed in the drivetrain/bellypan. All the other motor controllers, wiring, sensors etc have to be mounted on the module/subsystem it self.
To explain this principle and design requirements we’ve made a couple explaining slides in a presentation:

This one sums it up pretty neatly:

To make sure we’re able to work in this way and design sub systems we’re taking on a different working method for the sub systems. We’ll be designing the robot using the principles of lean product and process development/knowledge based product development. We’ve written an article on this application within FRC.
Throughout the week we’ll explain a little more on this method since it will become more clear with proper examples while prototyping.
2019 - Koomen_Visser - Application of LPPD in FRC - Final.pdf (397.2 KB)

We’ve divided the robot into 6 major sub systems, not in order of priority:

  • Drivetrain
  • Intake
  • Storage/sterilizer
  • Outtake
  • Climbing
  • Control panel

Initial breakdown of the game and robot can be found in this spreadsheet: Robot skillslist & Subsystem analysis - Google Sheets

Tab1 - Robot Skillslist:
We started with breaking down the game in every single function/skill the robot could preform on the field, the list is generated by separating the team in sub teams and eventually pitch and add onto the entire list.

Tab2 - Scoring analysis:
After that we’ve done an scoring analysis on the importance of scoring powercells vs. climbing.

Takeaways:

  1. Climbing is key. 25 points for solo climb plus 15 if level, with potentially receiving another RP if our partner climbs and we level the switch.
  2. To equal climbing score (25) with powercells you either need: 4 outer power cycles or 5 bottom cycles.
  3. Reasonable for 4481 for week 1: between 3 to 4 full court cycles. Low = 15/20 points, Outer = 30/40 points.
  4. A outer 3 ball auto = 12 points which almost equals 3 low goal cycles > Outer circle outer is very important!
  5. Reaching stage 2 in week 1 will be less common making the control panel activation les interesting but definitely needed for worlds!
  6. A reliable climb is worth investing a lot of resources in (time etc).

Tab3 - Climbing analysis & Tab4 - Intake analysis:
A quick run down on the first requirements

Control panel, outtake and storage/sterilizer will be worked on at today’s meeting. We’ll be looking at shooting the powercells and a 2 powercell wide intake.
A update from today’s meeting will be posted tomorrow!

Drivetrain
We’re going for a 8wd 6" pneumatic tank drive out of sheetmetal, dead axle.
Using the 6" WCP pneumatic tires and designed our own hub.

Dimensions are 650 x 800 mm. Which is ± 25.6’ x 31.5’.
Check out the design below, this will be hopefully manufactured before the next weekend so we can bend and assemble it on Saturday during the day. We’ll also build the AM KOP drivetrain for prototyping.

Currently geared for 14 ft/s with a 12T pinion gear on the NEOs. We can switch to 11T or 10T if we want to gear it down but we’re currently looking at flying over the field dukes of hazard style in 4-5 seconds.

Wheel assembly

It will be a combined out of flat sheetmetal and a 3D printed hub out of polycarbonate/nylon/cpe. We’re receiving our wheel order from WCP on Wednesday and these prints will be done on Wednesday as well.

The dead axle design allows for easy maintenance on the wheels and the eventual hubs will be printed in 2 different colors so we can see which wheel has to go where depending on the amount of sprockets.

CONCLUSION
This is as far as we’ve gotten at this time!
Goals to accomplish by Wednesday:

  • Designs in progress for all the prototypes we want to build and test on Saturday. We’re trying to design our prototypes with a couple features we can test with the same prototype and test + document the results hence the design takes a little longer.

  • Have everything ordered at the vendors and sponsors to make sure we have 2 drivetrains up and running by Saturday.

  • Have a clear goal for what we’d like to build for week 1 and the level of required performance.

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