Hi, in core you get to study overall subjects related to the branch you have taken up. In specialization you will have to study deeply about the degree you have chosen. For Robotic engineer core is the better option if you don't have a specific degree in your mind. Below are few questions that you can answer for yourself to find a better and the most optimum branch.

1. What subject am I passionate enough about to study for the next two to seven years of my life?
2. What type of course should I choose to have the career that I want? (which leads to the question: What career do I want!?)
3. Which specific degree course is the best one for me?
4. Where do I want to live for the next two to seven years of my life?

Hope this helps.