Hi, I'd like to help you with your question.
I understand your dilemma. It is difficult to know what is a normal way to respond in a situation like this when you are abused as a child. Your feelings are legitimate. Just because these people are your parents does not mean you are obligated to have a relationship with them. Often times, parents who abuse do not stop when their children grow up. They may not be able to hit them anymore, but they still can emotionally/verbally abuse.That, plus the trauma from being abused, makes it imperative that you do not subject yourself to a relationship with your abuser. And there is a peace to having no contact with an abusive parent. For seeing them again brings up the feelings and reminders of the abuse. It is being victimized all over again.
Here are some resource that may help you decide what to do:
Adult Children of Abusive Parents: A Healing Program for Those Who Have Been Physically, Sexually, or Emotionally Abused by Steven Farmer
An Adult Child's Guide to What's 'Normal' by John C. Friel Ph.D. and Linda D. Friel M.A.
You can find the books on Amazon.com or your local library may have them for you.
The link may have support groups or chats from others who are in your situation and can offer some insight into how they have handled the situation with their parents.
Let me know if I can help any further,