Being a South African botanist, I am no expert on North American flora, but from what I can see on your photos its unlikely to be a Jerusalem artichoke (Helianthus tuberosus of the Asteraceae family). I have experience only with cultivated varieties here in SA, but the wild forms which are indigenous to the Great lakes region of Canada and the eastern USA may look quite different.
Why I say its unlikely to be the Jerusalem artichoke is that the leaves visible on your photos are too uniformly narrow and the flower heads I can see all have only have 9 ray florets (petals), whereas as the Jerusalem artichoke has broader ovate-elliptic leaves (though the lvs higher up on the stem are often narrower than the lower lvs) and generally 10 to 20 ray florets. Check out Wikipedia for a good description and pics of the Jerusalem artichoke. Just remeber, wild forms can differ quite markedly from cultivated forms of the same species.