Control model for an over-determined fluid dynamic planar drive

A compact planar drive for the use in small machine tools has been developed. It is based on a fluid dynamic drive principle which enables translational motion in x- and y-direction as well as unlimited rotations around the z-axis in any position. Thrust forces are generated by deflection of 12 individually controlled fluid jets on the slide’s flow grids.
This paper presents a three-layer control system for the novel drive. The top-level motion control calculates decoupled drive forces and torque for the slide’s three mechanical degrees of freedom (DOF). Since the drive is over-actuated with 12 control inputs for the three DOFs, a control allocation algorithm coordinates the redundant thrust forces. The bottom level features the valve control for every single jet. First experiments demonstrate the functionality and limitations of the control system.