The stepwise regression procedure was applied to obtain measurement formulas for equilibrium parameters used in the feedback control of JT-60, because the measurement formulas for feedback control of a D-shaped divertor plasma position and shape could not be derived from an analytical approach. This procedure automatically selects the predictor variables required to identify the plasma control parameters to leave as few variables as possible. The measurement formulas obtained are simple and compact, making them suitable for rapid calculation in a digitized feedback control system. The resultant control system proved to be stable and reliable, and it was experimentally confirmed that the measurement formulas obtained through this procedure were accurate enough to be applicable to the feedback control of plasma configurations in JT-60.