Looking at the robots it’s pretty easy to say that almost all robots have one or more grabbing mechanisms. Now my team tossed around a lot of ideas before settling, and I was wondering how well your designs work. What kind of grabber did you use? How well do you have to line it up before you can grab? How long does it take? How well does it hold? How far away can you be from the goal when you grab? And please be honest i know everyone is really proud of thier robots but it doesn’t always work the way its supposed to, so just tell what you’ve seen.
Without going into too much detail, we designed a very simple grabber which can quickly grab a goal 100% of the time. Angle of attack, speed, timing, etc. don’t matter (i.e. no lining up is necessary). It holds very well, and the only way a goal can come loose is if the entire grabber assembly is ripped form its frame.
Our grabber has two spring-loaded latches that hold onto the goal. It passively grabs onto the goal by simply running into it–it should work no matter the angle as long as there is a foot or two to “jiggle” the goal.
Stephen
we have a wedge with 2 claws that completely capture 2 bars with pressure, it is designed in such a way even with a pnumatic failure once closed they cannot be opened and only 1 claw on a goal is enough because of the wedge. With switches the capture is automatic or manual with a joystick. With this design it is almost impossible to move a goal we have. We have another non relese one.
Here is a pic:
http://www.firstrobotics.net/02gallery/329-1.jpg
team 25 can grab to goals and place them in under 9 seconds
Ours is shown here
http://www.chiefdelphi.com/forums/attachment.php?s=&postid=20899
we can get to the goal(only 1) in about 2-3 seconds and we hit it at full speed, notice the reinforcement on the front of the bot. The drivers have a little over 3 weeks experience before we shipped it. We have all wheel steering off the line to line up to any of the 3 goals depending on the situation
Team 159 can grab the goal in ~3 sec hitting it at full speed.
Andres
639 is looking at about 5 secs to grab and lift goal
here’s a movie (note this was our first attempt at grabbing the goal so the driver had very very little practice):
We auto dock with the sensors and a pneumatic claw that turns in its track as it deploys, there’s no getting it off unless we decide to unlatch, it all takes 5-10 seconds depending how far the bot it away from the goal when you push the autodock button. The claw can latch behind any pipe and even if its only behind one pipe it works just the same.
asher