Linear Delta Printer Kinematics
Kinematics is the study of motion or movement in space. In the case of Linear Delta Printer Kinematics we are interested in how the (linear) motion of three carriages along identically spaced vertical columns is transformed into the movement of the tip of a hotend in the usual Cartesian system of X, Y and Z coordinates.
In mathematical terms this boils down to the relation between a three dimensional vector (x, y z) and another three dimensional vector (X, Y, Z).
We can distinguish between forward and reverse kinematics depending on whether we are trying to determine (X, Y, Z) from (x, y, z) or the other way around.
This PDF document by Steve Graves provides a clear, easy to understand explanation of Linear Delta Kinematics for 3D printers: File:Rostock Delta Kinematics 3.pdf