I have heard a little about you Dr. Joe. You are a legend. I still use your spreadsheet on chainvisualizer. It is very useful. Thank you.
To answer your question about CAD. For a FIRST Robotics team, you can get any CAD software for free: PTC Creo/Elements (formerly called Pro/E), Solidworks and Inventor. Our high school uses PTC software for CAD classes so it was a no brainer for us.
For the benefit of students, I would recommend Creo or Solidworks. That's what good engineering schools are using these days and many small to medium size companies also use them.
In terms of software functions, PTC Creo/Elements is the best. And it is closest to the high end software like CATIA V5, making it easier for students to learn in the future.
In terms of ease of learning, Solidworks may have a slight advantage. PTC Creo is more rigorous in terms of expecting you to do things correctly and won't allow sloppy work. Otherwise, students may get into bad habits of just putting something in that look close enough.
Here is the link to get started with free PTC software. It is
www.ptc.com/go/first and click on the link at the bottom. They have very nice and free online tutorial called PTC University that covers many topics from very basic to advance uses. If you have any questions about PTC University, just PM me.
Since you use Pro/E at iRobot, I am sure you don't need me to tell you about it.
Self disclosure: I gave you my honest opinion even though PTC happens to be one of our sponsors