Magnetic Crawler X-Y

HI

please I need to make one magnetic crawler for my project.
that can move continuously at one speed - in Y direction , min 10 mm / sec to 50 mm/ sec
and second motor / connected in front carrying a probe, ( testing unit ) move -x to + x directions in span of 100 mm.

details as below.
I just need your theoretical approach and parts selection / as I have several with me. and your support.
help to code, I will be able to complete this project, that can crawl on tank, has carbon steel ( Magnetic ) plate.

please let me know how you can help me.. attached for your quick reference.

Pramod Myakal

myakal@gmail.com