@botix. Ok - so now all of your posts should come thru to this one - which is a start.
As we mentioned to you in the chat forum then you need to give a lot more info on what the robot needs to do - include a link to the competition page you are building it for. I gather yo've already done the $50 robot but, beyond that, this is your first task - and a very difficult one at that.
We, via chat, advised that YOU should come up with some suggested solutions and the members would then be more than willing to comment - but asking them for a total solution will not work. Why? Well I guess I spend 30 seconds on each new post (such as this). After that time: if I dont understand the question then I wont even reply. If the question is way too vague then I also wont reply. Also if the questions requires an entire book to answer then I also wont reply.
So you need to do a whole heapfull of research on your own first.
Dont forget that if YOU want to build a robot, then it is YOUR challenge for YOU to build. WE can help with bits'n'pieces but unless we have previously built something that does exactly what you want then we CANNOT give you a quick and total solution (else we would enter and win the same competition).
Good luck