Robust shape control in a sendzimir cold-rolling steel mill

The shape control problem for a Sendzimir 20-roll cold rolling steel mill is characterised by operation over a wide range of conditions arising from roll changes, changes in rolling schedules and changes in material gauge, width and hardness. Previous approaches to the problem suggest storing a large number of precompensator matrices to cater for the full range of operating conditions. This paper, on the other hand, attempts to synthesise a controller which is optimally robust to changes in the conditions associated with the rolling cluster, resulting in a reduced storage requirement for the controlling computer. The performance of the robust controller is evaluated via nonlinear simulation

Special issue on wind turbines and wave energy devices

The stability of a control system that has been tested on the Controls Advanced Research Turbine (CART) is analyzed. Focus is on adaptive generator torque control with constant blade pitch to maximize energy capture of a variable-speed wind turbine operating in region 2 wherein an adaptive strategy is shown to improve wind turbine performance. It is demonstrated that the rotor speed is asymptotically stable under the torque control law in the constant wind speed input case and L2 stable with respect to time-varying wind input. Further, a method is derived for selecting positive gain in gain adaptation law to guarantee convergence of the adaptive gain M to its optimal value M*