Hello all, i am thinking of a new project to work on in 2020 the picture shows my rough idea, i have made some cnc machines before including a standard medium size gantry style router so i have gained a lot of experience in that style and the simple cartesian coordinate system of motion and location.

My main lack of understanding comes from the non cartesian movement of the crane style i have quickly plotted in the picture. i need to figure out what control setup or work flow will let me deal with this rotary X and linear Y and Z axis so ican operate in a normal 3D cartesian coordinate system. my understanding is that i will use something like a typical self contained stepper motor motion generator which seems to not do any multi axis calculation and edit the outputs compared to the inputs it gets from jogging commands or a nc program generated from fusion 360 say which has your standard linear 3 axis set up. so what are my options if any one knows?

A little bit more about this idea of mine, the arm is 6m long, i intend to at first use it for plasma cutting of large metal sheets i do not intend for it to be a super rigid setup for milling metals but i would like enough rigidity to stop it deflecting under its own weight or from unloaded moderate speed motion, say giving it a -+0.25mm accuracy? preferably +- 0.05mm, i know plasma cutting doesnt require precise accuracy since plasma cuts are pretty varied to begin with.

I would also like to add an a and b axis head to it with a small high speed spindle for cutting wood, plastic and foam sculptures, i will tackle the simple plasma operations first but i would like to know that this sort of setup could be rigid enough to at least do the sculpting of light materials.

The reason i want the crane design is it takes up next to no room on the shed floor, the shed is about 14x7m i can put the main pivot in a corner and use the space under it and just pull in a water table and start plasma cutting sheets, as for anchoring down chunks of wood or foam for 3d carving im guessing a heavy metal plate on lockable wheels with fixtures holding on to the work piece will have enough weight to stay put, if not i will think about drilling some holes in to the concrete to make anchors for the base.
If i make a standard gantry style one with the same work area as this crane it will still easily fit in the shed but i will have the rails and rack and pinion that the gantry runs on sitting in the middle of the shed being an annoying obstacle when the machine is not in use