You said "final year", didn't you? This is basic statics & dynamics analysis.
F = ma
T = Jα
Should be sized for maximum acceleration (increase from speed1 to speed2, then reverse to stop). Include every possible resistance to motion you can dream up (friction, gravity effects, efficiencies, any & all inertia effects) in order to size for "peak torque" on the rotational axes. Once you have that, then you size your motors, gear trains, etc., to match.