There are no references to my knowledge on global controllability of non linear systems except algorithmic approach for this problem in finite state systems (which is NP hard). But you may look into Vidyasagar's book for affine case also see Nijmeijer and Van der Craft. Most results of non linear systems are local in nature. Affne systems seem to simplify the problem for which the rank criterion of controllability distribution gives a condition. But even this is not easy to numerically compute since that involves global solution to non linear equations. Hope this helps.