[Ri3D] ‘Snow Problem 2018 Thread

Another year, another 'Snow Problem thread for Robot in 3 Days! We are extremely hyped for FIRST Power Up and we’ve been working hard in preparation for this year’s build. Our goal is to give you a bunch of quality content in videos, white papers, and social media as we possibly can.

We’ll be posting our content in the following places:

  • CD-Media – All our white papers will be posted here, including our strategy analysis, our prototyping overviews, and our final robot walkthrough, as well as anything else we want to talk about along the way.
  • Ri3D YouTube – We’ll be posting more polished daily overviews on the official Ri3D channel, as well as our reveal video and robot walkthroughs
  • Our YouTube – This will be more “uncut” footage on here following our prototyping groups from concept to prototype to final execution, as well as uncut footage of our robot reveal video shooting session
  • Twitch– As always, we will have a live stream, with audio and a nice view of our whiteboard wall for the strategy session, and no audio because the copywrite fairies don’t like us blasting sick jams after that.
  • Twitter – Follow for robot memes and notifications when we release new content!
  • Facebook– Will have Facebook-y things on it. Like updates. Probably, I guess.

Note: Facebook and Twitter are largely there for people who are already invested in those platforms–we don’t intend to release anything major to those platforms exclusively-- you really should be able to follow the main takeaways from our build via our whitepapers on CD-Media and the videos we’ll be posting to YouTube. We realize there’s a lot of information out there for people to sort through, and intend these various channels to make it easier-- not more difficult-- to find the biggest things we learn during the build.

Our stream schedule will be approximately as follows (all times CST):

  • 2PM - 7PM, January 6th – Strategy Discussion, into Prototyping Discussion
  • 7PM-12AM, January 6th – Drivetrain building, Prototyping
  • 9:30AM-12AM, January 7th – Prototyping
  • 9:30AM-12AM, January 8th – Prototyping and Final Fabrication
  • 9:30AM-12PM, January 9th – Finishing touches

We will also be doing a reviews stream, where we talk about some of the products we’re using to build our robot, and giving you our honest thoughts on them. That will be at 7PM each night, on our Twitch Channel. We’ll also be on FUN during their daily recaps.

Additionally, we will be targeting releasing the following white papers:

  • Strategy Analysis - Saturday Night
  • Prototype Concept Analysis - Sunday Night
  • Prototype Overview - Monday Night
  • Final Robot Technical Walkthrough - Wednesday Night

We have a few other ideas for white papers to do, including one on the hydro-dipping process we’ll be trying out this year, on our manufacturing techniques, and autonomous strategy, but may or may not be able to get those out during the build. Let us know if you want to see something in particular!

As always, thank you to our sponsors-- AndyMark, REV Robotics, PHD, iR3 Creative, The University of Minnesota - College of Science and Engineering, Anderson Student Labs, CSE Expo, University of Minnesota - Student Union and Activities Fund, and all the parents and friends who keep us fed through the 3 days! We could not do this without their extremely generous continuing support. We would also like to thank FRC teams 2169, 2175, 2220, 2470 and 4778, as well as FTC teams 8686, 9205, and 11190 for their support during our previous builds. This community is awesome and the reason we keep on doing this!

Looking forward to watching this year! Thank you for everything you guys put in.

Our strategy guide is now up on our CD-Media page, as of about 1AM this morning. We may update it later today.

We also have our first round of prototyping videos out on our YouTube channel here. They talk about our initial concepts and prototypes. We also have a video summarizing our strategy session here.

Check them out and let us know what you think! If you have any questions, I (and other 'Snow Problem members) will be watching this thread, so let us know!

I think having your shop/office above a chipotle is amazing and dangerous! :smiley:

It is. We’re above a Chipotle, across the street from a Cane’s have a Naf Naf Grill and Punch Pizza next door… too many good food options here :slight_smile:

Hi Everyone! 'Snow Problem has been busy creating a bunch of videos documenting all of our prototypes/testing for 2018 Ri3D. Here is a compiled list of links to the content that is currently out there! Stay tuned for more in the coming days.

'Snow Problem YouTube Channel: https://www.youtube.com/channel/UCBv8vHAnG_1f9Ie_K1CrZCw/feed
'Snow Problem 2018 Ri3D Prototypes/Tests Playlist: https://www.youtube.com/watch?v=AM4jP8gsKwk&list=PLgClIqwEW9hAcLjoxnKlxTHLwZx56xf7I

Detailed List of Current 2018 Ri3D Video Content:
Day 1 - Catapult Test with 2016 Robot


Watch us test out the idea of a catapult by launching the Power Cube with our 2016 Ri3D robot, Perses!

Day 1 - Intake Prototyping Part 1


Check out some successful preliminary wheeled intake prototype testing for the Power Cube!

Day 1 - Initial Strategy Discussion


Listen to the highlights reel of 'Snow Problem’s initial 2018 Ri3D Strategy Discussion.

Day 1 - Catapult Prototyping


Check out our tests of three different Power Cube catapult iterations. Note the difference in angles (number of stairs the prototype is propped up on) as you watch!

Day 1 - Reversibility Mechanism Prototyping


We explored a mechanism to reverse a wheeled Power Cube intake - here are the results!

Day 1 - Prototypes Recap Discussion


Listen to our thoughts on the six different prototypes that we explored during Day 1 of 2018 Ri3D. Prototypes discussed include: Wheeled Intake, Catapult, Wheeled Shooter, Reversibility Mechanism for Intake, Scissor Lift, and Elevator Lift.

Day 2 - Angled Ramp Intake Prototype


Our design strategy requires that we intake the Power Cube and shoot it out at a steep angle. Take a look at this concept to see how we might adjust the angle of the Power Cube inside the robot!

Day 1 and 2 - Wheeled Shooter Prototyping


Curious to see how “So… What this means is we could do a wheeled shooter” goes from a team joke to a viable game strategy? Then check out our progress on our Power Cube shooter prototype!

As of about 1AM last night, our prototyping findings/concept paper is up here. If there are any further questions on it, we’re happy to answer them. We had some trouble getting pictures of our CAD prototypes because everyone doing CAD has been deep into design since about 9PM last night getting parts ready for manufacture today.

'Snow Problem has been busy creating a bunch of videos documenting all of our prototypes/testing for 2018 Ri3D. Here is a compiled list of links to the content that is currently out there! Stay tuned for more in the coming days.

'Snow Problem YouTube Channel](https://www.youtube.com/channel/UCBv8vHAnG_1f9Ie_K1CrZCw/feed)
'Snow Problem 2018 Ri3D Prototypes/Tests Playlist](https://www.youtube.com/watch?v=AM4jP8gsKwk&list=PLgClIqwEW9hAcLjoxnKlxTHLwZx56xf7I)

Detailed List of Current 2018 Ri3D Video Content:
Day 1 - Catapult Test with 2016 Robot
Watch us test out the idea of a catapult by launching the Power Cube with our 2016 Ri3D robot, Perses!

Day 1 - Intake Prototyping Part 1
Check out some successful preliminary wheeled intake prototype testing for the Power Cube!

Day 1 - Initial Strategy Discussion
Listen to the highlights reel of 'Snow Problem’s initial 2018 Ri3D Strategy Discussion.

Day 1 - Catapult Prototyping
Check out our tests of three different Power Cube catapult iterations. Note the difference in angles (number of stairs the prototype is propped up on) as you watch!

Day 1 - Reversibility Mechanism Prototyping
We explored a mechanism to reverse a wheeled Power Cube intake - here are the results!

Day 1 - Prototypes Recap Discussion
Listen to our thoughts on the six different prototypes that we explored during Day 1 of 2018 Ri3D. Prototypes discussed include: Wheeled Intake, Catapult, Wheeled Shooter, Reversibility Mechanism for Intake, Scissor Lift, and Elevator Lift.

Day 2 - Angled Ramp Intake Prototype
Our design strategy requires that we intake the Power Cube and shoot it out at a steep angle. Take a look at this concept to see how we might adjust the angle of the Power Cube inside the robot!

Day 1 and 2 - Wheeled Shooter Prototyping
Curious to see how “So… What this means is we could do a wheeled shooter” goes from a team joke to a viable game strategy? Then check out our progress on our Power Cube shooter prototype!

Nick - I just got done reading through your prototype doc, very well written and laid out!

I did notice a gap though… you guys considered a 4-bar arm, and talked about why it wouldn’t work. But you didn’t discuss in the doc any other type of arm. My team spent a while looking at possible arm designs on Saturday, and think there are several that would be viable, although like you we ruled out the 4-bar design. Did you guys do any thinking on other designs?

We did not significantly discuss alternative arm designs, however, several designs come to mind.

  • Simple bar
    – This would be just a single bar actuated via a sprocket or pneumatics. It has the same issue as a 4-bar, where the arm can’t actually be long enough to reach a fully unbalanced SCALE without going over 16" outside the frame perimeter. It also means you may need to add a wrist, as the cube wouldn’t be in the same global orientation once you’re in position to score. - Chain-arm
    – This would be a single bar with sprockets that keep the end effector parallel to the ground. Has the same issue as a 4-bar, where the arm can’t actually be long enough to reach a fully unbalanced SCALE without going over 16" outside the frame perimeter, but maintains the simplicity of the 1-bar at the cost of chain. - 6-bar
    – This design is common in VRC, where you can get more extension from a 4-bar by offsetting the bars. It also has the same issue as a 4-bar, where the arm can’t actually be long enough to reach a fully unbalanced SCALE without going over 16" outside the frame perimeter. - Double-reverse 6-bar
    – This is another common design in VRC, where you have another set of 6-bar linkages (or 4-bar linkages) to gain even more extension. We believe that this would alleviate the issues with the 4-bar by allowing us to use shorter arms to achieve the required extension plus a considerable margin, but we have not actually done the math for this. Some good resources for making these would be looking at robots from VRC Skyrise or this year’s game, In the Zone. We do have some concerns about building one at an FRC scale as far as stability versus center of gravity.

My sketching has shown that a 4 bar could work with a 148 style wrist from 2007. However, it’s a tight fit in the envelope.



We have been going with 7+ feet for the height we want to be able to score in the SCALE, under the consideration that we may need to score on top of POWER CUBES that are already in the SCALE, in a situation where the scale is in it’s maximum height. We realize this is a worst case situation, but being able to be put in a situation where your primary mechanism is ineffective is a scary thing to us, at least from the perspective of a team trying to be competitive.

In the prototyping paper, You state that on a 33” side of a robot you can have a 25” opening, wouldn’t only accept a 21” opening? How does that affect the intake on a wide side

Very valid points. The 4 bar seems to be an inefficient use of volume as well. With the COTS options for linear elevators these days, it’s rapidly becoming a compelling design choice to me.

My math may have been off when I was writing that :stuck_out_tongue: It’s been a long few days! I’ll fix that!

Edit: Deleted the old file, and uploaded a corrected version

I love watching these but I really wish Ri3D would make it easier to find the content that the different teams put out, there doesn’t seem to be any central place that links to all the streams/youtube channels for ALL of the teams, and while the Ri3D Channel itself does post some highlights, it’s far from all-inclusive.

I’ve been working on compiling all of the information for Ri3D streams in one spreadsheet. It’s currently at 8/14 teams but I’ve been updating as teams come up (if you’re an Ri3D team and you would like to add your info slide into Nick’s DMs to get access, we’ll need your email).

Small update-- we’re finalizing CAD and manufacturing final parts for the robot-- here’s a peek at our CAD:

Obviously there’s some stuff missing, but the key geometry has largely been worked out.

As someone who help build a 4 bar mechanism for 2015, I would highly recommend against it. It ended up being much more complex that anticipated and was a pain to get working just right. I agree that elevators are a much more desirable option.

Wow that looks nice, this is the idea I was having for a vault/switch robot

The high angle indicates to me that you might be trying to shoot the cubes into the scale. Watching your prototype videos it didnt look like you got a cube above 4 ft at any angle. Purely out of curiosity, do you plan on launching them up high? If so, how do you plan to get that added force to launch them up higher?

Also, I love your intake! It would be really nice to see some videos of that prototype intaking cubes at weird angles, orientations, etc.