Here are two Autodesk Inventor tutorials helpful to robot CAD.
Download Inventor and FRC Parts FREE
Autodesk offers its top quality professional software for free to students in High School and FIRST robotics. Consider downloading Autodesk Inventor 2016 and play with it at home. At the shop, we use Autodesk Inventor 2016.
Also, toward the bottom of the page is a lot of standard FRC parts. We will have the parts on a server here. Also, all robot parts and assemblies will stay on site for simplicity and control. This means designs can only be added to the robot from workstations at MTHS.