Consider prototyping in stages. For example:
Stage 1) quick mockup - PVC pipes and wood scraps, c-clamps and wood screws, metal scraps where needed for strength. No motors/gears/belts/chains, just manipulate parts by hand. Try multiple concepts.
Stage 2) Add quick and dirty motors/gears/belts/chains, experiment with different speeds and materials and ball compression. Refine as you go.
Stage 3) Make a more robust proto intake and hack it onto an old robot base from a previous year. Drive the mockup around chasing balls to test the pickup in a dynamic environment, try picking up balls trapped in corners, picking up a ball from a clump of balls, etc. Testing on carpet with texture and friction similiar to a tournament playing field.
Here is a link to video of 971 following this process for 2016 intake
(segment from 5:17 to 6:38).
Here is a link to 971 robot in a match
- view of the intake self centering action at 0:58 and 1:10