pre-charged Pneumatics

when we go to mesure the perimeter of the robot can we have a pneumatic piston charged (ie pulling somthing back) or does it have to be empty. thanks for the help guys

no, i believe everything has to be uncharged and powered down during inspection, but i’d ask the GDC/ consult the rules first

thanks… the rules arent very specific on that topic

I disagree. I believe this is perfectly legal for wieghing and sizing.

In the past teams have had srping loaded protrusions and expansions that activated at the start of the match but allowed them to meet size requirements and I see this as no different.

A good portion of this year’s ball manipulation devices will be required to be pressurized to size during inspection. Explaining this to the inspectors as a precaution makes sense. Also remember every time you place your robot on the field this devisce will need to be charged fot the same reason.

IMHO you can go through inspection and place your robot on the field with charged pneumatics.

Peter and Howie,
This is the rule that applies…

<R90> The ROBOT will be inspected for compliance with the dimension constraints specified in Rule <R10> while in its NORMAL CONFIGURATION, by being placed within a FIRST Sizing Device that has inside surface dimensions consistent with the rule. Other than resting on the floor of the Sizing Device, no part of the ROBOT can break the plane of the sides or top of the Sizing Device during size inspection. The ROBOT must be self-supporting while in the Sizing Device.

Inspections are carried out with all systems unpressurized and unpowered for obvious safety reasons. Robot size and weight are tested with the bumpers off and the battery out. Please refer to Rule <10> and <11> as both are referenced in robot size.

The rules for stored energy govern the condition that a robot can be in at the start of a match including air stored in the Clippards. This rule allows teams to pressurize their robot with an off robot compressor but speaks to the start of a match, not to inspection. Please ask the question as we have no guidance to the contrary from the GDC. I expect the pressure vent valve to be open until the “power on” portion of the inspection takes place.

Missed that one Al.
It looks like a manual “safety” lock is how everyone will have to skirt this issue for inspection.

Or have your robot kick the ball without any parts extending past the frame perimeter. It’s possible.

Everyone really should have a safety lock available anyways. If you are going to be carrying the robot on or off the field with any mechanism “charged” and ready to fire, it needs a secure lock in place to ensure that any jostling doesn’t result in someone getting kicked in the gut and dropping the robot on their foot. That is a simple safety practice that every team should have (I would even go so far as to suggest that inspectors should fail teams without it) that can easily prevent real injuries.

Which leads to a question for Al… If a team had such a safety lock that was removed from their robot after placing it on the field, could they use it during the sizing part of inspection, but remove it when weighing the robot? If the safety lock is a few pounds for something real sturdy, it could make a real difference when being weighed.

I’ve always told my team to release the air pressure before lifting the robot off the field. It makes the robot that much safer and doesn’t take that much time.

Ahh, but not all mechanisms are “charged” with air pressure. Teams that utilize springs or surgical tubing with a motor to charge their kicker may, depending on design, leave the kicker in a charged position when the robot is off, while having no pneumatics at all! And other teams will pressurize their robot from the cart in order to save weight (not have a compressor on their robot) - in such a case, you would have to carry it onto the field charged.

FIRST provided some good safety guidelines for precharged devices (and this forum came up with some more) a couple years ago for the trackball launchers.

Mind you… if your ball kicker has as much energy stored up as a trackball launcher, you ought to be able to kick balls up into the stands.

My estimate so far is that we are using about 1/4 the force and about 1/2 the stroke on our pneumatic kicker that we did on our pneumatic launcher.

Jason

Everyone really should have a safety lock available anyways. If you are going to be carrying the robot on or off the field with any mechanism “charged” and ready to fire, it needs a secure lock in place to ensure that any jostling doesn’t result in someone getting kicked in the gut and dropping the robot on their foot. That is a simple safety practice that every team should have (I would even go so far as to suggest that inspectors should fail teams without it) that can easily prevent real injuries.

Which leads to a question for Al… If a team had such a safety lock that was removed from their robot after placing it on the field, could they use it during the sizing part of inspection, but remove it when weighing the robot? If the safety lock is a few pounds for something real sturdy, it could make a real difference when being weighed.

one of the big reasons they put the weight restriction on is because team members are going to be carrying the robot, it’s a safety issue.

Eagle,
The answer would be yes and no. A safety lock could be used but under the rules for start orientation, the robot (not humans) has to be able to remove the lock after the match starts. The robot must be able to hold itself in the same size it did when in the sizing box at the start of the match.

During previous games where mechanisms used considerable stored energy, the team had to demonstrate during inspection, that the stored energy could be released (safely and easily) prior to moving the robot on or off the field. One of the most impressive devices I have seen was on the Baxter robot during Overdrive. It used surgical tubing and a cam type charging device. To move the robot, a team member just needed to back the cam to the point where the tubing was no longer stretched. Those that played against Team 16 that year knows the effectiveness of that ball launcher.

Al,

I have to disagree with you (at least partially) on this one.

If the safety lock, when removed, will cause deployment of a mechanism, I agree.

If we are talking about making a trigger mechanism for a stored energy device absolutely foolproof safe but it’s removal does not cause deployment, I not only think it legal but almost mandatory.

We do not want accidental deployment of a mechanism when putting a robot onto or off of the field.

Let’s use a theoretical kicker for an example. It has a deflected spring and/or pre-charged pneumatic piston and a trigger that makes it fire. A pin in the trigger, removed after the robot is placed on the field, will prevent accidental firing while the robot is handled.

The pin is never part of the robot during a match. It is in a team member’s pocket.

I would call this legal and almost mandatory.

JMHO,

Mike

Mike,
I would agree on this example provided the robot was able to fit in the box and start the match without said locking device in place.

Aircraft usually have a collection of locking pins with attached flags saying “remove before flight”. They extend into visibility so that the ground crew can prepare the plane for use.

This is exactly the approach we will be using for our shooter’s safety pin. We will also try a similar approach for anything else that might save time and embarrassment, like forgetting to turning the main breaker on. :rolleyes: (Not that we have ever forgotten to turn the breaker on…more than twice a day during competition.:ahh:)

Mind you, anyone that has done this little boo-boo is immediately demoted to “Freshman” for the day, regardless of how long they have been on the team, in school, or beyond. This even extends to our Mentors… of which I am one,… and have worn this label. :yikes:

yeah, I’ve even seen them on robots!





Al, I think I also need to disagree a little here. As the rules currently stand, normal configuration definitely implies a powered-on, disabled state (“the state of the ROBOT immediately before being enabled by the Field Management System, before the ROBOT takes any actions, deploys any mechanisms, or moves away from the starting location”). Although for reasons of practicality and safety it would seem valid to inspect robots in their least-energy state, if doing so would inaccurately simulate the normal configuration during sizing, the rules would seem to demand that it be tested in the normal configuration (per <R88> and <R90>).

Of course, there are not many mechanisms for which this is a valid concern, because with control system outputs disabled, control of most actuators and other devices is not practical. One possibility that comes to mind is an electromagnet that receives power directly from the PDB, through a mechanical switch, and which holds down some component until that switch is triggered, cutting power. (This is a custom circuit, and by using a non-relay switch, avoids being controlled by the cRIO.)

Now, it is certainly within an inspector’s authority—and indeed, responsibility—to take steps to minimize the risk to themself and others during inspection. In the above case, if the team were to argue that they needed that component to be held back, but the inspector was uncomfortable with the presence of an armed mechanism in the sizing box, perhaps a compromise could be reached where the mechanism is fixed in the appropriate position, but in a locked-out state.

But in other cases, if the inspector considers the hazard relatively minor, I don’t think that the rules would prevent a team from asking to be sized in a powered-on, disabled state.

Tristan,
As I have pointed out in a different thread, we have received no direction from the GDC on any changes to the method of inspection. I cannot agree, based on past safety discussions and procedures, that transporting a robot with a charged mechanism, pneumatic or mechanical, is appropriate. If that is the case, then inspecting under different conditions is also inappropriate. Teams for many years have figured out ways to move robot objects into playing position that did not require charged systems to do so.
I think that the majority of this discussion likely is directed at kicking mechanisms. If the kicking device would fall outside of the robot frame perimeter without being in the charged state, it seems to me that the team needs to design their mechanism to keep the kicker inside the frame perimeter when at rest.