Command Generation Techniques for a Pin Array using the SVD and the SNMF

This paper presents two command generation techniques for improving the surface generation time of a pin array device, specifically a prototype called Digital Clay. The procedures use singular value decomposition (SVD) and semi-nonnegative matrix factorization (SNMF) to create intermediate surfaces that sum to a desired surface. Although the focus is on pin array control, the techniques can apply to any system with a set of subsystems coupled by the row-column input method. The row-column method allows multiple actuators to be controlled by a few inputs. Current procedures for systems using the row-column method are too slow for many applications. Recent work has improved the time response of these systems using simultaneous feedback control but can potentially create unwanted oscillatory behavior. This paper describes command generation techniques using the SVD and SNMF that maintain the improvement in time without the oscillations. Simulation results compare the two procedures to the line scanning technique used in previous work on pin arrays.