[Ri3D] Ri3D 1.0 2015 FRC Robot Reveal
 

Ri3D 1.0 has completed the Robot in 3 Day challenge and we're proud share the completion of our robot "Franken Totes Ma Goats."

View the video here: https://www.youtube.com/watch?v=nRJwIhfKJO0

We hope you enjoy and feel free to ask questions.

Re: [Ri3D] Ri3D 1.0 2015 FRC Robot Reveal
 

I love that roller mechanism.

How did you manage to operate (close/open) the roller arms while keeping them compliant with the shape of the tote/container?

Re: [Ri3D] Ri3D 1.0 2015 FRC Robot Reveal
 

Hi Dan, Do you have something other than a musical youtube video... maybe an engineering notebook, or something else with more technical detail and insight explaining your design decisions and the various tradeoffs involved? Thanks.

Re: [Ri3D] Ri3D 1.0 2015 FRC Robot Reveal
 

Great Robot!

Especially the wheels to align the totes! That is something we did not think of and I actually think is a great idea!

How reliable was the 4 bar? we were debating doing that for a little but decided it would be too hard to do.

Re: [Ri3D] Ri3D 1.0 2015 FRC Robot Reveal
 

We'll have another video that explains a bit more on how it works but the simple gist is that the arms are spring loaded and only actuated open. They are free to expand as needed but are constrained by a hard stop on either end. A DART is able to push them open when needed. We thought about pneumatic here but decided it might be nice to have some control on the width when navigating in tight spaces. The actuator seemed to be a way to achieve that.

Thanks! We were thrilled with how the wheeled intake came together. Quickly acquiring a tote at any angle is critical this year.

The 4 bar works very well its fast, doesn't back drive and is smooth to operate. The primary limiting factor for weight is how much a tote can support before damaging the handle. Something that we didn't show is that with a little bit of programming the wheels can be reversed to adjust the bottom tote into position on the downward ark. This makes the operation for the driver nearly as simple as the linear lift, though maybe more programming intensive.

We also like the fact that we have some forward reach if needed. There is a decent chance there will be "debris" on the field which you need to reach over to achieve a stack.

In terms of challenges, we had to do a lot of work to make the structure as rigid as possible. I also don't believe we 100% nailed the packaging. We created a 2D CAD that landed the linear actuator in what we felt would be an optimized position. But a structural change caused us to need to move the linear actuator clevis down a bit and changed our range of motion.

I'm planning to create a tutorial over the next few days on a method to design linkage systems like these as well as a handful or other linkage designs we looked at using.

I'm sorry you didn't enjoy the music. Stay tuned for more technical details, tutorials and how to's. Also feel free to watch our other videos for more insight into why we made certain decisions. We will be creating playlists to make hunting for team specific content easier.

Re: [Ri3D] Ri3D 1.0 2015 FRC Robot Reveal
 

Thank you.

Re: [Ri3D] Ri3D 1.0 2015 FRC Robot Reveal
 

As promised here is a playlist of our current videos. We have another more descriptive video being posted tom.

http://www.youtube.com/playlist?list...yXSuJn6OujkNQd

Each of the teams now has a playlist and of all of their videos. This should help organize the thought process of each of the teams.

Re: [Ri3D] Ri3D 1.0 2015 FRC Robot Reveal
 

What motor/gearbox combination do you have spinning the wheels on your intake? What is the reduction? What diameter wheel is it?

We are potentially looking at a similar intake are trying to knock out the details. Thanks in advance!

Re: [Ri3D] Ri3D 1.0 2015 FRC Robot Reveal
 

The 6" Hi-Grip wheels were direct drive off a PG-71 from Andy Mark. The arms were spring loaded in the closed position using recycled trampoline springs. They were actuated open by a 6" DART. We'll do some more to describe this soon.

Re: [Ri3D] Ri3D 1.0 2015 FRC Robot Reveal
 

We liked the universal claw for engaging totes on either long or short edge. We are a rookie team, so fewer moving parts is a good thing.

Any tips on reproducing the cut pattern? We have been calipering all the tote lip elements and transferring them to posterboard...it is slow going! Next we would do cardboard prototypes and finally cut the pattern out of aluminum sheet stock. Maybe we're overthinking it.

Re: [Ri3D] Ri3D 1.0 2015 FRC Robot Reveal
 

I don't know what kind of CAD capabilities you have, but if you have the ability to use a CAD software you could download the tote and use that to help you create the shape.

Re: [Ri3D] Ri3D 1.0 2015 FRC Robot Reveal
 

I really like the thought of using CAD, but based on this thread about tote CAD files:
http://www.chiefdelphi.com/forums/sh....php?p=1421295
...it looks like the tote model measurements are in question. It seems physical measurement will be the safest approach for precise outcomes.

Re: [Ri3D] Ri3D 1.0 2015 FRC Robot Reveal
 

As promised here is a little bit of a deeper dive into our robot and decision making: http://youtu.be/I7jfwprVXMY

We did not CAD the tote claw.

Instead we took an iterative mock-up based approach - measure, cut, measured again, cut.. start over.. cut.. measure.. reinforce.. etc... I know that sounds crazy but we weren't 100% sure what the best fit would look like. Each time we thought we had a layout nailed we discovered another feature that would improve it.

Andrew Remmers and Gabe Salas did a great job to perfect it. We were happy with the end result but I'm sure there's still room left for improvement.

If you're looking to reverse engineer it I would:

Find two video clips of it front on and in profile > Screen capture those clips > Bring screen grabs into CAD and trace the profile > Scale mock up and iterate

We are still chipping away at CAD for 4 bar and "tote magnet" / roller intake concepts.

Re: [Ri3D] Ri3D 1.0 2015 FRC Robot Reveal
 

How did you mount the wheels onto the PG-71? We are looking at using the PG-71 we got in the KOP, but we don't know how to get a wheel to stay on in the vertical position. There doesn't seem to be any connectors on the gearbox besides mounting threads.

Re: [Ri3D] Ri3D 1.0 2015 FRC Robot Reveal
 

A hub and 3/8ths retaining clip should hold a wheel to the motor.

Re: [Ri3D] Ri3D 1.0 2015 FRC Robot Reveal
 

But the shaft on the gearbox is not long enough to go through a hub and a clip.

Re: [Ri3D] Ri3D 1.0 2015 FRC Robot Reveal
 

We attached the wheel with a Flex Hub Flange and put a 3/8" shaft collar that we reamed out for 10mm on the other side.

Only 1 side of the wheel was supported.

There are more robust ways to achieve this set up but this is what we had available to use.

Re: [Ri3D] Ri3D 1.0 2015 FRC Robot Reveal
 

Are you sure you were using a 10mm key hub? If I recall correctly the 10 mm keyed hub from andymark is shorter than a normal hub.

Looking at the cad it fits (plus I've done it before in real life).

3rd image is the distance from the end of the shaft to the hub provided there is a 1/16th inch gap between the hub and the gearbox body.

Re: [Ri3D] Ri3D 1.0 2015 FRC Robot Reveal
 

A couple of guys on our team created paper profiles of the tote lips, long and short, then cut them and combined them into a profile that closely resembles the hook on the Ri3D 1.0 robot. The paper profile was a good test fit for our tote. We then modeled it in SolidWorks. I attached a thumbnail image, and here is a link to a DWG if interested.

https://drive.google.com/file/d/0B1M...ew?usp=sharing

Re: [Ri3D] Ri3D 1.0 2015 FRC Robot Reveal
 

This is a really impressive robot for 3 days! I love the wheel rollers to align the totes. Good job!