EDIT: Ninja'd, though there are exceptions for unconscious. Reference MP 42. How would that work if you, the ranger, were denied actions, such as through being dominated?
Good catch, I missed that bit. As far as dominate goes, that would count as "present in the encounter but unable to command the beast" as described on p. 42. So the beast would move to a spot adjacent to the character and then be able to act freely.