pic: Roborio mounting and protective case

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[faust1706]

I am not expert in CAD, but I am really interested to see a stress analysis of this case. I do not have CAD on this laptop because it is not powerful enough to run the software at a manageable level.

If you're going to post a CAD file of a case, the least you can do is strength test it in software

Originally Posted by faust1706

I am not expert in CAD, but I am really interested to see a stress analysis of this case. I do not have CAD on this laptop because it is not powerful enough to run the software at a manageable level.

If you're going to post a CAD file of a case, the least you can do is strength test it in software

Hold on let me just support my entire robot with this roborio case so that it has a stress I can analyze for you.

In the event you really do not understand the most basic concept of a case, let me explain it to you:

-The Roborio sits comfortably inside the case
-The case sits bolted to your electronics pan
-Nothing else happens

I hope this has been helpful to you, and if there is anything else I can do, please don't hesitate to ask.

[wasayanwer97]

Originally Posted by Andrew Lawrence

Hold on let me just support my entire robot with this roborio case so that it has a stress I can analyze for you.

In the event you really do not understand the most basic concept of a case, let me explain it to you:

-The Roborio sits comfortably inside the case
-The case sits bolted to your electronics pan
-Nothing else happens

I hope this has been helpful to you, and if there is anything else I can do, please don't hesitate to ask.

I don't know about him, but I'd sure like to see a stress analysis.

Call Andrew Pizza Hut, because he better deliver.

[faust1706]

Originally Posted by Andrew Lawrence

Hold on let me just support my entire robot with this roborio case so that it has a stress I can analyze for you.

I'm a programmer, but I'm willing to bet money on if you design something for industry, you have to extensively stress test it in software before implementation is ever thought of. It's kind of like with code, only it's called unit testing then. Bill Gates got so much free programming time because someone who wrote the login info to computers back then they didn't unit test their code. When prompted to put time, he simply put a letter, and the software couldn't make sense of it so he got to use the computer for free.

NASA wouldn't have gotten to where they are today if it weren't for extensive stress testing, in software and in the lab.

I think it would be a good habit to get into the ensure what you design can serve its purpose in the worst case scenario. What if brakes of a new car failed after 10,000 miles? What if pacemakers fail after 4 years?

It may seem silly for a little case, but it pays off. It gets you experience, and isn't what this is all about?

This is a bit off topic, but I had an interview today for an internship for developing software. One of the questions was how I unit test (stress test) my code. It is important to do, and it could be the difference between getting a job or not. You never know.

And if you really don't want to do it, I'm sure there exists some program online that allows you to upload a cad file (I don't even know what extension they have....) and it will do it for you, or you could figure out how to do it in whatever software you designed it in.

I could easily see the quality award going to a team that has documentation about their robot's durability (and of course a good robot) How much the frame will deflect during a collision, stuff like that. It shows good engineering practice.

[Joe G.]

Originally Posted by faust1706

I'm a programmer, but I'm willing to bet money on if you design something for industry, you have to extensively stress test it in software before implementation is ever thought of. It's kind of like with code, only it's called unit testing then. Bill Gates got so much free programming time because someone who wrote the login info to computers back then they didn't unit test their code. When prompted to put time, he simply put a letter, and the software couldn't make sense of it so he got to use the computer for free.

NASA wouldn't have gotten to where they are today if it weren't for extensive stress testing, in software and in the lab.

I think it would be a good habit to get into the ensure what you design can serve its purpose in the worst case scenario. What if brakes of a new car failed after 10,000 miles? What if pacemakers fail after 4 years?

It may seem silly for a little case, but it pays off. It gets you experience, and isn't what this is all about?

Good engineering practice is to not over engineer or overanalyze things. If this case was protecting components for manned space exploration, on which lives depend, and was something never-before-done, then yes, extensive stress testing would definitely be in order.

This is not going into space. It is a simple protective cover for a relatively replaceable component in a robot designed to play games, for a robot whose operational lifespan will be measured in hours, using materials the designer has almost certainty used in similar applications dozens of times, in an application that is highly weight sensitive. Given these constraints, stress analysis is a waste of the designer's time, and overbuilding the case to withstand any freak accident imaginable in FRC is poor use of resources.

Nice case! Have you considered implementing cable retention into the base piece?

[EricH]

Originally Posted by Joe G.

Given these constraints, stress analysis is a waste of the designer's time, and overbuilding the case to withstand any freak accident imaginable in FRC is poor use of resources.

For example, designing it to withstand a combination of hits that sheared a 1/4-20 bolt. That's a LOT of OUCH! And, yes, I have seen that happen. It also happened to be a bolt that was holding a battery holder on. The battery was plainly visible shortly afterwards, and the robot wasn't moving.

A more reasonable test would be bouncing a Frisbee or a ball off of a robot's side panel that was made of similar material, several times, as hard as thought to be reasonable (grab a freshman and tell him to break it using X, but stop after half an hour, for example). If it breaks early, redesign. If it doesn't break (probably won't), you should be OK.


There's a time and a place to do analysis. A case to try to keep FOD out of the controller, you pretty much need enough strength to hold it together. A robot frame, you need a bit more for some reason...

[mrnoble]

A 1/16" sheet of polycarbonate will not shatter no matter what you do to it.

Are the standoffs 3D printed, or are they aluminum or steel? Even with the 10/32s running through them, that would be the only part I'd have any concern about. It looks great and my team would totally use something like it. We've already printed a mock up of the roboRio for our off season bot, so we're right there with you.

[Electronica1]

Could you modify the 3d printed base to include something like this?

Originally Posted by wasayanwer97

I don't know about him, but I'd sure like to see a stress analysis.

Call Andrew Pizza Hut, because he better deliver.

Wasay, I'm feeling more like Digiorno right now.

Originally Posted by Joe G.

Nice case! Have you considered implementing cable retention into the base piece?

Thank you! It wasn't in my original design, but as Electronica1 mentioned below, it's definitely possible to.

Originally Posted by mrnoble

Are the standoffs 3D printed, or are they aluminum or steel? Even with the 10/32s running through them, that would be the only part I'd have any concern about.

The standoffs are printed as well (they are a part of the base - they don't come off), but with a decent enough wall thickness to hold their own (it's an odd number due to the wall thicknesses driving the overall dimensions of the case, I forget the exact number). I'm sure aluminum standoffs could be used just as well.

Originally Posted by Electronica1

Could you modify the 3d printed base to include something like this?

It definitely can include something like that. There's plenty of room.

[nathannfm]

Originally Posted by Electronica1

Could you modify the 3d printed base to include something like this?

Agreed, if you are going to all the trouble to print what amounts to something that could be made out of plywood and wood glue you might as well take advantage of the 3D printers abilities, like some sort of cable management on all sides.

Also, the 2+ in long steel bolts and nuts could be removed if you made the holes in the standoffs a bit smaller and tapped them from both ends (or tapped from just the top and just velcro the entire thing to the robot)

[Alan Anderson]

Originally Posted by philso

Alternatively, use the case to clamp the Roborio to the bellypan and dispense with the Velcro.

That's a very good suggestion. I'll try to remember it when it comes time to design the electrical layout for our 2015 robot.

[Woolly]

Originally Posted by Alan Anderson

That's a very good suggestion. I'll try to remember it when it comes time to design the electrical layout for our 2015 robot.

Well, if you're going to enclose the Roborio somewhat anyway, what about getting some rubber/flexible 3d printing filament and making somewhat of an otter-box for the Roborio?

[cadandcookies]

Originally Posted by mrnoble

A 1/16" sheet of polycarbonate will not shatter no matter what you do to it.

You know, some people might take that as a challenge...

[mrnoble]

Originally Posted by cadandcookies

You know, some people might take that as a challenge...

Have at it. I'm sure you can freeze it to -30C and have something weird happen.