which course I have to do for robotics in bits pilani?

If you mean Robotics as a branch of engineering, then BITS Pilani does not offer it. But that doesn't in any way mean that you can't pursue robotics from BITS Pilani. What I mean by that is that there are a lot of ways in which you can learn robotics from BITS. Firstly, there are two technical teams called Team Robocon and Team Acyut in BITS. These teams participate in international robotics competitions. Team Acyut makes a humanoid robot \U0001f916 and Team Robocon makes a robot according to the problem statement of the competition. Both these teams do great work and make amazing robots.

Now, do you need to be a part of these teams to know and learn about robotics? Absolutely not. You can definitely even learn about robotics on your own as there are lots of people available here to help you. First of all, there are seniors who are always there to guide you and give you a direction. You can seriously learn a LOT from seniors here. Apart from that, there obviously are professors here who are very knowledgeable about robotics and are even doing research on it. They are also always there to help in any way they can. You can very easily approach any such person and they will be ready to help you.

So there are plenty of ways in which you can pursue robotics from BITS Pilani