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Unread 28-01-2010, 17:43
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Tristan Lall Tristan Lall is offline
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FRC #0188 (Woburn Robotics)
 
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Re: pre-charged Pneumatics

Quote:
Originally Posted by Al Skierkiewicz View Post
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.
That's not exactly the point I was making; basically, there's a balance to be struck between a team's possible expectation (following directly from the rulebook) that the robot will be inspected in the normal configuration (powered, disabled), and the inspectors' need to perform a safe inspection.

If some aspect of a robot is designed to comply with the size limits only when powered (i.e. in normal configuration), and it can be inspected safely while in this state, then there's no need to categorically insist that this particular robot be unpowered during inspection. But by the same token, if the inspector cannot safely perform an inspection while this particular robot is powered, then there's no question that he has the right to instruct the team to make their robot safe while still accurately simulating the normal configuration. (For many robots, an accurate simulation of normal configuration could be achieved with power off, pneumatics discharged, and springs at rest position—they're not the ones I'm concerned about.)

The exact steps necessary to achieve this will vary from robot to robot, but might, for example, include disconnecting the cRIO and all nonessential circuit breakers, while still allowing the custom circuit to remain powered. That's totally reasonable for something like a lifting hook that is retained electromagnetically, but which doesn't pose much of a risk. That's not necessarily sufficient for something like an electromagnetically-retained ball kicker, because of significant amounts of energy stored in the system.

In principle, I think the safety lock system envisioned by eagle33199 would be another reasonable way to address this (obviously provided that the lockout method was adequate). The lockout doesn't have to be elaborate, just effective: for low-energy systems, it might be a zip tie in place of an electromagnet, for higher-energy systems, it might be a well-placed two-by-four physically stopping the kicker from reaching its outermost limit.

Last edited by Tristan Lall : 28-01-2010 at 17:49.