Thread: Minibot deployment
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Unread 28-03-2011, 13:43
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Re: Minibot deployment
Our deployment system is similar to the concept above.

We initially thought about a plate that dropped down or extended that matched the base profile. We quickly threw that out in favor of "flippers" that are deployed pneumatically. On the end of each flipper there is a sw that puts it in an auto mode. If 1 sw is "true" it drives that side at 20% and the other at 40% until both switches are "true", once both sw are "true" it continues to drive both sides at 20%. So if someone tries to push the bot off the pole before the 10 sec mark it continues to stay glued to the pole. This allows the bot to line up with the base within +/- 1/4" of the pole center.

For the actual deployment system we initially tried numerous scissor mechanisms but none had the performance we desired. What we ended up with was some 80/20 on slides powered by doubled back surgi tube. The tray has a "tongue" that fits into a slot in a square tube carrying another cylinder with a piece of round UHMU threaded over the end. The tongue extends past the square tube and has another hole for a safety pin with a long "remove before flight" tag. That is used to lock it back into to position for removing from the field and safety for transport to the field. The surgi tube is connected to the back of the 80/20, the elevator tower, and loops around rollers attached to the square tube holding the retention cylinder. That gives tension even when fully extended giving a second chance if it doesn't attach to the pole on the first try.

The tray also has a "V" shaped slot to account for the +/- 1/4" possible misalignment. The tray has slots the "feet" of the minibot slide in and towers that support the "wings" on either side of the minibot.

Other teams figured out with a big enough slam they could knock it loose. So we added a hole in one of the "feet" underneath the tray. We added a bolt with the head cut off so the shoulder of the bolt passed through that hole. The other end of the bolt was attached to the square tube directly behind it. That locks the minibot on the tray until it is extended. Once that was added to our and one of the teams borrowing our minibot no matter how hard they slammed us the minibot wouldn't budge until it was deployed.