Quote:
Originally Posted by iCurtis
<snip>There are a lot of great teams in 2007 that didn't actuate at anything close to 180 degrees/second. There probably are some that did too</snip>
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In 2007, 1075 built a multi-position pneumatically powered arm (a single cylinder drove it, under control of 3 air valves [supply valve, exhaust valve, and direction valve]) It was able to stop anywhere in its travel, and used PID control to stop where we wanted it to (at the three heights, plus the floor) using a potentiometer. It was FAST. I would not be at all surprised if it approached 180deg/sec. It never seemed in danger of tearing the robot apart, to me at least.
It did however have PID issues where it would oscillate around the set point occasionally, particularly if air pressure fell below 60psi and the valves stopped operating consistently.
It was a much-improved derivative of our 2004 off-season arm, which was also multi-position pneumatic, (and as far as I know, one of the earliest examples of multi-position pneumatics using KOP valves in FRC [at the time, you were restricted to using the valves that came in the KOP, which were standard single and double solenoid valves, without an 3rd setting to stop the cylinder])