My 2017 return printed with estimated tax payments for next year. It printed four payment vouchers. I didn't ask for this. Am I obligated to make these four estimated

If you do not wish to make the estimated payments, do not send them.  The estimated form is not a part of your 2017 filing and the IRS will not expect them.

However, if you do end up owing the IRS in 2018, they may penalize you for not filing your estimated tax forms.

I also had estimated payment vouchers, but instead of realizing that's what they were, I sent them in as my 2017 payments. My state didn't credit them as such, so now I owe penalties. This optional payment should be clearer. It shows up much earlier in the printed form than the actual payment voucher that I should have paid.