Re: COTS: How far should it go?
 

Why do so many people have problems with Cots? Sometimes I want to take a nap and there is no bed nearby.

Re: COTS: How far should it go?
 

I do not see what the big fuss is about. There is nothing revolutionary in the kits, with the exception of the WCP MCC (which I will come back to in a minute). Previously, people would look at old video of what was successful on CD or photos from previous regionals. Let's use the case of a roller intake for a spherical game piece. There are only so many ways to pickup a sphere off the ground using the actuators allowed in FRC. A "shaft full of wheels" or "tube with grippy material" on a rotary joint is a lightweight way to grab a compressible sphere without needing precise alignment (remember you are driving from 50 feet away). In the past, someone would ask for help or details of how teams did it the last time we had a compressible spherical game piece. Soon there would be robot photos, mostly on CD, and people could quickly figure out what parts were needed to build the design and order and assemble them. Now there is a convenient kit you can order with less clicks. The end result is the same, roller intake using the same principle as years past, with the exception that some teams who are less good at searching these forums are now aware of the kit and can buy it COTS. It is also important to note that just because you buy the kit, does not mean you have to use all the pieces or make it exactly as the photo shows it. You may choose change the arm dimensions, motor used, gearing or wheel size after testing.

Same thing goes for gearboxes. You are designing a set of spur gear reductions and maybe adding a chain sprocket reduction at the end. Spur gears need to have their centers positioned within a few thousands of an inch of each other. If you don't have a precise way to get the gears mounted correctly they will destroy each other. There is a still a ton of physics and design tradeoffs with COTS gearboxes (1 vs 2 speed, 2 vs 3 CIMs, Gearing ratios optimized for time to distance, pushing max current at traction limit, etc)

We could keep going into all the COTS parts, but the end result is the principles are the same and vendors are making the execution easier and easier. The seven simple machines have not changed, their execution for FRC has just become easier (assuming you can afford to buy them).

On the note of the MCC, it is tempting to say that this will "break FRC" because you can purchase a robot. Let's be clear you are only purchasing the mechanical components, not the software, ability to drive or game strategy. You could give identical robots (with identical software) to teams and it would still be a ton of fun to watch. Remember that just because the MCC or KOP kit does something one way, does not require you to do it the same way. Maybe you change wheels or gearing ratio or the size of your roller intake wheels. Keep in mind that with publicly released designs (MCC, Ri3d), that everyone else sees them and is looking to design something at least as good as those designs, if not better. You can also design defensive strategies that counter these publicly available designs.

Personally I would like to see 20 MCC designs ready to go at the competition with working software and instructions on how to use them so that teams who tried their best and for whatever reason were not able to make a bot that can score points would get to participate in the C part of FRC (competition).

I am going to link to an old reply of mine on essentially the same topic since many of the points are valid. It also shows how many times this discussion has come up (though it is good to revisit it once a year).


Final note - as a team that used to have access to CNC machines, it was nice to be able to get into the details of fabrication with students and make custom gearboxes (even if COTS was cheaper and lighter). Now that we do not have access to these tools, we focus our attention from fabrication theory (i.e. climb vs conventional milling, surface speeds that give good finish, how to cut various materials and how to efficiently program different milling operations with the fewest setup) to constrained design theory (we want to make motions like X,Y,Z that fit in area A and we can chose from Q set of parts that we can afford from vendors 1,2,3)

-matto-

Re: COTS: How far should it go?
 

Simple moving parts - such as bearings. Seriously?

This conversation is drawing a lot of heated attention.
I see it as teams learning between design engineering and systems engineering and that's great.
I see more functional robots than I have in years. Bring on more components, limit the complete assemblies.

Re: COTS: How far should it go?
 

What if a weaker team wants to design their own bot? If other teams are using COTS parts, it forces everyone to be at that level or better (if they want any chance at all).

Re: COTS: How far should it go?
 

What's wrong with raising the floor?

Re: COTS: How far should it go?
 

This is absolutely true - and a large part of the reason that it is imperative that FRC teams support one-another... There absolutely should be support built into the system - the only question is 'How much'?

I answered "yes" to most of the above items. I like the KOP Chassis. I like having COTS gearboxes and actuators... I overall like Ri3D.... However, I do think a line has to be drawn somewhere. When I look at the WCP robot, it looks like they are selling as a "kit" all the parts (plus assembly directions) to a robot that would be very competitive. They also advertise that it can be assembled in "a few days.".... It seems to me to be too much. What I like about the KOP Chassis is that it gets a team rolling, only needing a little bit of "know how." Then, less-experienced teams can become productive with the addition of one or two manipulators. The description (and endorsements) of the WCP robot suggest that a team with very little knowledge and effort can immediately become a force at district and regional events. This goes too far... If there is going to be a "kit," it should be something that allows a robot to be productive/useful - but not "competitive."


Teams don't need to be an alliance captain to have a good weekend. However, they so need to feel useful in a match. And, yes, having two or three wins out of 12 is way better than going 0-12.

I really don't know how I feel about the Rhino drive or the AndyMark intake system... I do think this

Re: COTS: How far should it go?
 

You didn't finish your sentence. I think you intended to write " ... design their own bot, and beat the other bots on-the-field."

Why are these hypothetical students building this hypothetical robot? To win a regional, or for some other reason(s)? Or for all of the above?

If the answer is "all of the above", they might be trying to fit 10 pounds of stuff into the 2017 version of FIRST's 9 pound bag.

Re: COTS: How far should it go?
 

I've always put this metric at "played in the afternoon on Saturday once in 2 or 3 years. It's by no means dominant. But it's demonstrating that they CAN do it. That's how you change their lives. And that's our entire job as mentors and volunteers, "hey kid, you can do this". If we have to simplify the problem a bit (or a lot) who cares? At the end of the day, it doesn't really matter if the student designed the gearbox that drove the robot. It matters if they feel STEM is a viable career choice for them. [1]




[1] And they don't need to decide to go into STEM, that's not a failure. You can lead a horse to water and all that jazz. Except, maybe in this case, we're just showing the horse a different stream that it didn't think was there before.

Re: COTS: How far should it go?
 

My answer to this is the same as my answer in the other thread:

COTS parts can make it easier to get the initial bit of success, so that you desire to overcome challenges rather than just give up.
COTS parts do not necessarily remove the drive to do better, or to learn more so you can improve the pre-existing solutions.


Those two points can be achieved with custom parts. They can also be achieved with COTS parts.

I believe COTS parts make success, and therefore inspiration, accessible to more teams.

As long as COTS parts continue to fulfill those two points, I'm fine with them.

Re: COTS: How far should it go?
 

One of the mentors on my team complains about having access to a machine shop & CNC machinery. One day I may ask him if he expects us to wind our own motors or smelt our own copper.

Once you're in industry, you're expected to look at what is out there first before designing something from scratch. You are not (usually) being payed to reinvent the wheel. If it already exists and meets the requirements, it's typically cheaper to use than invent yourself.

I think the COTS items help create a more level playing field. Several of you are now asking "How does that work". Where it helps is for those teams who don't have access to full machine shops and water jets. Being able to purchase premade components off the shelf helps level the playing field with those teams. It's a matter of tradeoffs and picking your battles.

Re: COTS: How far should it go?
 

I put some of the super-basic parts in the list because it was brought up on the other thread... Personally, I think it would be nuts to try to create your on bearings (or many other parts) for this... It also is meant to demonstrate a continuum.. None of us are going super-natural and mining our own ore (yes, that would be ridiculous) and, therefore, we rely on some outside manufacturing. However, the question as to how far should it go is really an interesting one.

Re: COTS: How far should it go?
 

Inspiration does not mean that a team has to win a regional. It does mean they have to be able to demonstrate to the world that they can do something, score a small percentage of the goals in a match. It means the team has something that can be built on. It means that they have hope of improving themselves.


I have worked with several team that "make the top 70%" possible. Their robots barely moved on the field. They lost matches where the strongest robot on the opposing alliance sat dead. I can confirm that the team members and mentors (myself included) started wondering if this is a worthwhile use of their time and resources. Some of those teams have still not recovered from the bad decisions they made years ago. I was told by one of the parents on one of those teams that one of their major sponsors had started wondering if the program was worth supporting. Even if the sponsor believes in the mission of FIRST, they might think about supporting a different team.

Re: COTS: How far should it go?
 

Personally, I voted only for item #1. I've always insisted on the following:

• students must design and construct their own bearings, and
• students must use only stone tools which they make from scratch.

Edit: no I don't.

Oh NO! It means everyone has to try to get... better. Sorry for the snark, but if the goal is for teams to build things with no assistance or expertise, and out of hardware store supplies like string and pvc pipe, I recommend BEST robotics. It's also free to enter. My kids do it in the fall.

Re: COTS: How far should it go?
 

I really don't care if anyone flaks me for this. I really don't which is unusual for me, but I think what people aren't recognizing is that in a lot of these arguments all the parts mentioned "raise the floor" and do nothing for the "ceiling". Which is kind of unfair, but so is life.
If AndyMark along with the Rhino released a bunch of parts that higher level teams are dying for I think this conversation would be different.

As for inspiring, see 4.6 R18.

"There is no restriction on the quantity of COTS items or items which do not meet the definition of COTS or FABRICATED (e.g. raw materials) that may be accessed by a team at an event."

Is it not inspiring to see a team which looks down and out for the count make a comeback because they have access to COTS parts?

Finally, and this ought to be a fun thing to throw into the mix, isn't this just a different version of the cheesecake firestorm. Who was inspired when a robot got cheese caked? Or in this instance, who is inspired when people roll around in the (pardon the pun) COTtage cheese...

Man I feel bad reading that pun...

Re: COTS: How far should it go?
 

ITT everyone agrees that COTS parts are a great things, and agree that purchasable FULL mechanisms or FULL robots are not.

There is probably some minor dissent on the latter part, but it certainly isn't prevalent here.