Re: pre-charged Pneumatics
 

Ether,
Any transformers on the robot would be LAN isolation devices and allowed as part of the supplied control system, there are no loop antennas as the Wireless bridge has two dipole antennas and is also part of the supplied control system. Inductors and other large coils of wire as well as servos fit into the allowed motors section of the rules or are part of the supplied control system boost/buck power supplies. While loops in wire are effectively solenoids, straightening the loop will not result in a change of function nor is the magnetic field useful so these have been ignored in the past as cosmetic.

Re: pre-charged Pneumatics
 

Dave,
As you are lurking here, I would hope that the GDC is at least discussing this inspection process as it applies to sizing, "self supporting" and charged/powered/deflected inspections. I am always available for discussion.

Re: pre-charged Pneumatics
 

The prohibition is not against solenoids, but against ELECTRIC SOLENOID ACTUATORS. Solenoids might just be a coiled wire carrying current, but adding the word "actuator" makes the intent clear to me. If powering your electromagnet results in a piece of the robot moving, it breaks the rule.

Re: pre-charged Pneumatics
 

Thanks Alan, that's exactly what I though, but I could not find the words.

Re: pre-charged Pneumatics
 

I agree with the above. The GDC use of the word "solenoid" does not include any of these devices.



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Re: pre-charged Pneumatics
 

That's probably the clearest way to state it, and seems consistent with all posts by GDC to date (as updated this morning).


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Re: pre-charged Pneumatics
 

Another real-world example to put to the test. A team is using surgical tubing to provide all the force for their kicker - thus, when "charged", there is a lot of stored energy in the tubing. To "charge" the kicker, they use a cam driven by a motor. The assumption here is the cam is set up such that it can stop in a "fully charged" state, and by turning as little as a few degrees provide a rather explosive discharge of energy through the kicker - requiring another full revolution to become fully charged again. Note that for the kicker to be "fully charged", the robot does not need to be powered on, assuming the cam is difficult/impossible to back drive.

During play, the expectation would be that a kick would simply be a full revolution of the cam - go from fully charged, to kicking, to fully charged again. In the "default state", the code would always return it to fully charged, and within the frame perimeter, to avoid penalties and the yellow card mentioned for the 2-second rule. This is a relatively stable system - the kicker can return inside the frame quickly, and while not in use will remain there should power be lost on the robot. (of course, if power is lost the the half second immediately following a discharge, the kicker may remain outside the frame, but this would be a rather exceptional circumstance)

To be in compliance with the rules, such a robot would have to arrive on the field "fully charged" - carrying it as such would not be safe without redundant safety measures to ensure it couldn't fire if the cam was jostled too much, and hopefully EVERY team with such a system would have safety devices in place.

For inspection, the sizing portion would have to be done in this "fully charged" configuration. During such an inspection, would the inspectors permit (or hopefully require) the safety mechanisms to be in place during sizing? Would they allow them to be removed after the robot was placed on the scale (but before the weight reading was taken)? Depending on robot design, such safety mechanisms may have to be fairly significant (fairly large weight) if, for example, a simple pin (fairly lightweight) can't be used due to access restrictions from other parts. The addition of a single pound of safety equipment on the robot may be enough to put teams over the limit.

Please note - the concern here isn't over safety (the assumption is all proper actions have been taken to ensure the device is safe when being handled), it's not over penalties or the 2-second rule, and it's not over the actual operation of the robot on the field. It is simply in ensure that teams can be safely inspected while having a consistent understanding of what can and cannot be done while weighing and sizing the robot.

Re: pre-charged Pneumatics
 

Eagle,

Unless you want to post your question to the GDC, we inspectors will not have a definitive answer for quite a while.

Let me suggest this: Volunteer to be an inspector at your regional (they always need more volunteers).

Furthermore, volunteer to work the sizing box and scale.

You need to process 60 robots in just a couple of hours (everyone waits until the last minute) and 30 to 40% will require multiple trips to your station...

Keep in mind it's not just you. it's 60 teams of students that are putting the robot into the box and onto the scale. One of them might include your son or daughter...

Now, what would you feel comfortable with?

Regards,

Mike

Re: pre-charged Pneumatics
 

Eagle,
It would seem that a simple application of surgical tubing in front of the kicker in your example would prevent it from extending beyond the FRAME PERIMETER and still allow sizing with the kicker in the fired (non-deflected) state. This is the requirement we used in your first year although only one or two robots used a system like this in Minnesota that year. As I remember it was one of the Cat teams who had discussed this with me prior to the regional and had it corrected by the time they were inspected. This is also an excellent example of Mike's previous post about needing a locking pin to hold the mechanism in place while moving the robot to the field. Although for the life of me, I cannot see a good reason that a team would need to pre charge this device before a match begins unless it takes many seconds to charge. The safety to students and field personnel in the event of an accidental discharge staggers the imagination.

Re: pre-charged Pneumatics
 

Robots hanging from the tower at the end of a match may have their undersides exposed. Safety must extend inside the frame perimeter as well.

Just my 2cents.


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Re: pre-charged Pneumatics
 

The surgical tubing would simple be holding the kicker inside the frame, it should not need any unsafe deflection to do so.

Re: pre-charged Pneumatics
 

I believe the point was that the danger of an accidentally fired kicker is not restricted to whether or not it leaves the frame perimeter. During removal of the robot from the tower hands may be placed inside the frame perimeter and within danger of a moving kicker device.

I believe this example helps prove the superior safety of a rigid restraint as suggested by eagle33199.

I also fail to see how surgical tubing can restrain a kicker within the frame perimeter without compromising the energy being imparted in the portion of the kick taking place between the edge of the frame perimeter and the edge of the bumper perimeter.

If a rigid restraint system (locking pin, harness, etc.) is recommended when transporting the robot, it would seem to me that it would also be prudent to keep this safety system in place for as much of the inspection process as possible, including during the jostling as the robot is inserted into, and removed from, the sizing box. As long as the device can be shown to remain inside the frame perimeter with the device removed (while not being jostled and while everyone is clear of the kicker) there should be no rules issues here.

Removing such a device for weighing should also fall well within the rules as it is not part of the robot when the robot is in the NORMAL CONFIGURATION on the field.

Re: pre-charged Pneumatics
 

Kevin,
I was addressing the fear that a kicker that is not in firing position would fall outside the frame perimeter during inspection. A small piece of tubing would suffice for that purpose.

Re: pre-charged Pneumatics
 

<<A small piece of tubing would suffice for that purpose>>


Many teams are using surgical tubing for kicking. After kicking, they require substantial force to retract.



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Re: pre-charged Pneumatics
 

We don't know that yet.