Inverse kinematics for a cable robot?

Does anyone have a source that can teach me how to do the inverse kinematics for a wire or cable driven type of bot?  I wanna make a skycam that uses 3 steppers instead of the usual 4. 

Delta printers

I would use a RAMPS board set up as a delta printer.  You can use cartesian coordinates in the printer front end and program movement in g-code.

 

I am using ramps set up as a

I am using ramps set up as a delta but configuring it properly isn’t currently possible.  Ramps thinks that all delta robots have fixed length arms.  My design would change the length of the arms (since they are actually cables) so I cant actually use the IK built into ramps.  I was going to code some IK for cable driven deltabots but the only source that explains it uses a lot of mathatical notation that I dont understand.  Do you know of a way to compensate for changing arm lengths that in ramps that I dont?

Just a wag

I haven’t spent a lot of time thinking about this but.  can you trick the printer software into thinking the print bed is not flat.  The auto bed leveling feature might be tweaked to level out the movement.

have you built this yet. (and what are you building?)  i not sure the difference between cables and pillars with arms would make much difference on anything other then a printer.  ( I was thinking of building a “flying” camera platform before i shelved the idea.)