Rookie team--arm/manipulator design

[JimBryson]

I am a mentor on a brand new team (just started on the kickoff day) with only a couple mentors and only 10-15 students (mostly freshmen). We are almost done building the KOP base (just need to add the chains) and almost have the basic electrical system put together out. Friday we hope to be able to drive the base using the joysticks.

I feel we are way over our heads on arm/manipulator design and fabrication. Neither the mentors or the students have much design experience or fabrication equipment. Years ago, when my kids were little we used to watch the Great Lakes Regional, but I've never looked closely at how the arms are built.

Can people offer any advice how to begin designing it? We just don't know where to start. Are there design guides/resources online?

Thanks for any help anyone can offer.

[Madison]

The first rule of manipulator design is "don't bite off more than you can chew." You'll have a much more exciting, enjoyable, inspiring season if you keep things simple and build a robust, reliable machine. Reliability is always more important than potential.

This presentation -- http://d1pytrrjwm20z9.cloudfront.net...atorDesign.pdf -- is a good place to start. It's a balanced look at different options and the mathematical considerations of each.

[KrazyCarl92]

http://d1pytrrjwm20z9.cloudfront.net...atorDesign.pdf

Full credit given to Andy Baker.
This powerpoint shows some of the most commonly used designs over the years and shows a little about how they work and what they are good for.

This game is also very similar to the 2007 game, so you can look at matches from that year using http://thebluealliance.net

My suggestion would be to find one task that you can do really well and focus on making that a reliable and consistent capability. This all goes back to your strategy...defense? Score high? Score Low? Whatever it is, consistency is hard to come by in these competitions and it is usually better to do easy and simple tasks well and consistently rather than doing hard tasks inconsistently. Teams would usually rather pick a team that can score low 90% of the time quickly than a team who scores high 30% of the time and takes an eternity to do so.

You can also read this blog: http://jvengineering.blogspot.com
This guy (John V Neun) is a very respected FRC mentor and has a lot of great things to say.

[DonRotolo]

Originally Posted by JimBryson

I feel we are way over our heads on arm/manipulator design and fabrication.

You're on the right track, asking for help. We like to help. The resources already described will get you started, but remember that you can make a good arm with just a hacksaw, drill and file. Think about using 1" square aluminum tubing with 1/16" or 1/8" wall for the arm (or maybe a little larger), use aluminum alloy 6061.

Originally Posted by KrazyCarl92

Teams would usually rather pick a team that can score low 90% of the time quickly than a team who scores high 30% of the time and takes an eternity to do so.

Indeed. A team that is consistent beats a team that isn't, every time.

Also, now that the drivetrain is done give your drivers a LOT of time to practice. Get some carpeting and drive until the wheels fall off. Excellent drivers can make up for a lot of machine flaws.