Basically it would be a point to point positioner.
I would assume he would load the crane manually and then say push a button for the location he wants?
Some time back I did a similar magnet gantry crane that was used to stack rail wheels into a box car, it is a similar kind of operation, for this you could use a PLC with a couple of encoder input modules.
Or a standalone Galil unit such as a DMC-1500 would do it.
For either, a Maple Systems two line display and keypad input could be used for the operator.
The trickiest part is reading the motion travelled accurately, you do not want wheel slip or any such event happening.
I am 99% sure you are not going to get anything off the shelf, unless someone has done one exactly like it.
Most applications like this are one-off.
Al.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.