Controller development for a prototype high-speed low-tension tape transport

This paper describes the entire process of control system design for a prototype tape spooler that is used for conducting research into the dynamics of high-speed and low-tension tape transport, This multiinput/multioutput (MIMO) system has interesting dynamics that make controller design a difficult, iterative process, The tape speed and tension are regulated by controlling the torque applied to the supply and the take-up reels. Each reel is directly driven by a motor, and no capstan is used. The system has slowly time-varying dynamics due to changing reel packs, but more challenging are dynamics associated with low-tension operation, The spooler operates near a hard nonlinearity, because the tape only supports positive tension, At low tension, air entrainment in between layers of tape in the take-up reel causes the effective spring constant of the tape to rapidly decrease during start-up. This paper begins with physical modeling of the transport and proceeds through iterative MIMO system identification and controller optimization. Adaptive tension ripple cancellation and fault detection and fault compensation are demonstrated. Experimental data are presented which demonstrate tape transport at 5 m/s with 0.28 N (1 oz.) tension and a start-up time of less than 150 ms.