Al's Annual Inspection Thread

[Al Skierkiewicz]

OK,
Another year and another list. As we wind down to stop build in a few days, teams should be thinking about inspections coming up and should be performing a pre-bag inspection of their own.
1. The inspection checklist and the BOM template are both located here...
http://frc-manual.usfirst.org/
2. As Q&A or Team Updates modify robot rules, the Checklist may also change to reflect the rules change.
3. Stored Energy. Just about every robot will have some form of stored energy this year. To keep safety in mind at all times, springs will get an extra look by your inspectors. You may be asked to "dry fire" a shooting mechanism to check for the possibility of "destructive disassembly". If you are using COTS springs, please think about adding some type of cable (aircraft cable preferred) to keep the parts together should the spring crack or fracture. If you are using surgical tubing or some other form of latex or rubber, please be sure to have the ends secure. Inspectors may ask Safety Advisers for assistance in determining the safety of these mechanisms.
4. Bumpers. These are an issue every year and I am only mentioning them here so you can think about them. Bumpers do not need to be included in your bag with the robot. You do need them at competition and they will be required for practice rounds on the field. There has been a recent Team Update that allows you to use tape or other fasteners to affix the pool noodles to the "robust wood" to aid you in making pretty bumpers while you secure the fabric covering. Whatever method you choose, the intent is not to change the overall cross section of the pool noodle or compress it nor to add hard parts beyond the 1" dimension from the frame. Please refer to Fig. 4-8 for guidance.
5. Pneumatics. As last year, you are allowed to use any 12 volt DC compressor that does not exceed 1.05 cfm. If your compressor is not a common type, please be ready to provide documentation to show it meets spec. A new compressor that has become available requires a stainless steel, woven hose ( provided and as stated in the manufacturer's spec sheet) for operation. That has been ruled by the Q&A as part of the compressor and must be included. Reminder that pneumatics parts must be unmodified COTS devices rated for 125 psi working pressure.
More to follow, good luck everyone.

[eddie12390]

Originally Posted by Al Skierkiewicz

3. -snip- You may be asked to "dry fire" a shooting mechanism to check for the possibility of "destructive disassembly". If you are using COTS springs, please think about adding some type of cable (aircraft cable preferred) to keep the parts together should the spring crack or fracture. If you are using surgical tubing or some other form of latex or rubber, please be sure to have the ends secure. Inspectors may ask Safety Advisers for assistance in determining the safety of these mechanisms.

Does this affect pneumatic-based catapults? If so, will we be required to run it through the Driver Station/program or would the manual overrides provided on the Solenoids be acceptable for showing a test fire?

[Al Skierkiewicz]

Yes and we will ask you to dry fire using an powered and enabled robot in a protected area of the venue or a corner of the practice area if safe for others.

[Max Boord]

Originally Posted by Al Skierkiewicz

You may be asked to "dry fire" a shooting mechanism to check for the possibility of "destructive disassembly".

How does that work for all electric shooters? We have several shooter presets and a slow manual mode. Will/ could inspectors ask for us to dry fire all of them? Its powered by 6 cims so dry firing it could cause a problem.

Also if we instal a sensor to prevent dry firing (right now it just takes a button sequence) then will we be asked to bypass that sensor or will that exempt us from that test?

[Jon Stratis]

I'll chime in here with my biggest concern: R8, specifically the "cause unsafe conditions" part. This year many, many teams will utilize springs or tubing to create a mechanism that can fire with a lot of power. The last thing we want to see is a team picking up their robot and the thing firing without warning, injuring a student when it hits them on top of the head or under the jaw (given the speed and power of these shooters, I wouldn't be surprised if this caused a serious concussion or broke a jaw). Please, Please, Please design in some safety interlocks to make sure this doesn't happen! A locking pin, or a carabiner that can keep the shooter from hitting someone carrying the robot is really all that's needed.

[Al Skierkiewicz]

Max,
Should an inspector request a dry fire, it is because the mechanism looks unusual or appears to impart a large energy transfer. We are concerned about that "destructive dis-assembly" mentioned above. Many of our inspectors have seen these types of mechanisms over the years, and our concern is first and foremost the safety of all participants and audience. The last thing we want is a mechanism coming apart and launching it's kicker into the stands and injuring a grandmother or young child. We certainly feel a need to protect the field personnel. You don't want to hurt a ref or judge do you?

[BBray_T1296]

Spontaneous Deconstruction can plague any type of shooter. Elastic or electric or pneumatic

[kmusa]

Originally Posted by Max Boord

... Also if we instal a sensor to prevent dry firing (right now it just takes a button sequence) then will we be asked to bypass that sensor or will that exempt us from that test?

Al:

This is our situation as well. Pneumatic shooter, ball sensing interlock (eg shooter doesn't fire if the ball isn't present.) If we need to disable the interlock, we would rather do this in a way that is consistent with the interlock being as fail-safe as possible.

We'll certainly comply, but the ball (between it's weight, as well as it's air resistance) has a significant impact on the loads and speeds that the shooter sees when fired.

-Karlis

Originally Posted by Al Skierkiewicz

Why does this year's game remind me of Violet in Willie Wonka? Hmmmm?

So true. There are now two clips that I will forever look at differently. (The other is the image of the Poofs singing "Call Me Maybe" to Karthik - always brings a smile whenever I hear that song being played.)

[Al Skierkiewicz]

Karlis,
Your RI will figure it out when you are inspected.

[Andrew Schreiber]

Originally Posted by Al Skierkiewicz

Karlis,
Your RI will figure it out when you are inspected.

I'm sorry, that's unacceptable.

If there is a system in place to prevent dry firing is an inspector asking a team to bypass it a reasonable request? Should we anticipate it? Could you provide guidance under what circumstances this request may be made? (Being more specific than 'at the discretion of your RI' would be greatly appreciated) I am merely trying to understand the circumstances under which an inspector should ask a team to disable a safety mechanism which the team has deemed necessary given the behavior of their system.


I do not recall any such behavior in 2008 when more energy was stored.

[Jon Stratis]

Have you ever seen a fool-proof mechanism or sensor on a FIRST robot? I know I haven't... It would take quite a bit for a team to convince me that whatever system they have in place to prevent a dry fire isn't going to break at some point during the competition and allow the system to dry fire anyways. We've all seen some crazy stuff happen to a robot that no one expected...

[geomapguy]

If you don't the ability to do stuff manually in your code, then you are setting yourself up for failure. What happens if a sensor goes out during a match....you still want to be able to function without the sensor.

So honestly, just figure it out and stop crying about it...

[jvriezen]

So what I think Al and Jon are saying is that you should (and RI's will) assume the worst case that your robot will dry fire at some point unexpectedly regardless of your mechanisms designed to prevent that, because mechanism fail, especially when interactive with other bots.

If it only fires 'safely' with a ball loaded, then that is not good enough, and the robot is considered to be too unsafe for FRC standards, and it probably shouldn't be good enough for your team's standards due to the risk of serious injury.

Make sense?

[notmattlythgoe]

Originally Posted by geomapguy

If you don't the ability to do stuff manually in your code, then you are setting yourself up for failure. What happens if a sensor goes out during a match....you still want to be able to function without the sensor.

So honestly, just figure it out and stop crying about it...

That is not always the case. There are many times I'd prefer to not do something if a sensor goes out during a match than have manual control over it. I don't want a motor over driving through a hard stop because an encoder went out and the motor was manually over driven. Better to lose one match than break something on the robot.

Also, no need to be rude about it.

[magnets]

Originally Posted by Jon Stratis

Have you ever seen a fool-proof mechanism or sensor on a FIRST robot? I know I haven't... It would take quite a bit for a team to convince me that whatever system they have in place to prevent a dry fire isn't going to break at some point during the competition and allow the system to dry fire anyways. We've all seen some crazy stuff happen to a robot that no one expected...

I agree, there are no robots out there that are perfect.
You're saying that inspectors need to make sure that when the robot malfunctions, it's safe.

So, let's look at another malfunction. If my robot were to try to fire a ball as the intake was stowed, I'd break my intake. Does the inspector need to watch me break my robot that way too?

However, dry firing my shooter will break it, but pose no safety hazard.

This whole test is a bit stupid. It's kind of like asking teams to drop their robots from the top of the pyramid to make sure that when it falls, it isn't dangerous.