Quote:
Originally Posted by Stephi Rae
190 used a 6-ish-bar mechanism to obtain a "not-quite-rotational" motion to deploy the minibot ramp in 2011. (One of only two minibot ramps to "ship" with a robot in 2011, I believe, even though they were all the rage at champs. The other original ramp belonged to 233.)
Not an arm, but a linkage nontheless, and definitely complicated.
If I find a good video or picture that shows the linkage I'll edit my post to add it, at the moment I haven't found one. It was removed from the robot for the promo video so that we wouldn't give away the ramp idea before our first regional.
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I've attached a picture of the linkage Steph is referring to. It's a 6-bar (4-bar with a driver dyad) that lifts the ramp from its storage down low in the robot up and over the tower base. The virtual center (the point in space that the entire mechanism is rotating about at any given time) is always somewhere around the rear edge of the robot frame.
Another great linkage in FRC was 67's 2008
adjustable 4-bar. The operation was seamless, and very clever.