Applied state space feedback control of a deep drawing process

This paper presents results from application of discrete state space based feedback control of the blank holder force (BHF) magnitude and distribution in the drawing of a rectangular workpiece. By means of monitoring the flange draw-in during the punch stroke, the controller makes continuous adjustments to the BHF magnitude and distribution by individually controlling the pressure of a hydraulic fluid in a number of cavities embedded in the blank holder plate. The adjustments are conducted online during the punch stroke to minimize the deviation of the achieved flange draw-in from a predetermined reference.