Near-optimal tape transport control with feedback of velocity and tension

With the increasing recording areal density and volumetric density targeted by magnetic tapes, high-performance tape transport is of fundamental importance to achieve the required reliability in tape storage systems. In this paper, the time-varying characteristics of tape transport are taken into account to design a velocity and tension feedback control system using p-type controllers that depend on the longitudinal tape position. Analytical expressions are given for the controller gains, for which all transfer functions become essentially independent of longitudinal position. Experimental results are presented for a tape system where feedback of tension is provided by a tension sensing roller.