Robust Tracking Control On Speed Control System Of Cold Strip Rolling Mill

Based on Shanghai Bao Steel Co. practical project, which is modeling,simulating of dynamic rolling procedure and control optimizing for cold continuing roll mill, the research of control optimization on the DC motor speed control system is studied. Because the uncertainty brought by the time-varying parameters and the nonlinear uncertainty and the exterior load have great influence on the dynamic process and the tracking effect of the system, it has practical meaning and theory value to combine the robust control method and nonlinear theory to the control of speed system.The standard design problem and small gain theorem in the robust theory and the differential geometry in the nonlinear theory are firstly introduced, and the basic structure and parameters of the speed system for each stand of the practical cold continuing roll mill are presented. Aiming at the uncertainty brought by the rotating inertia and motor torque coefficient during the field weakening process, the mixed sensitivity robust controller based on inner mode principle is designed. The load of the DC motor has a great influence on the tracking effect of speed control system, so a kind of load disturbance observer is constructed to compensate the load disturbance, and a new variable structure controller is designed by employing Lyapunov speed error function. Secondly a robust controller is designed to restrain the uncertainty of the parameters and outer load disturbance simultaneously. Lastly the nonlinearity of armature reaction of the DC motor is considered, a variable structure controller is designed based on the feedback linearization method, moreover, a robust controller is designed which can restrain the uncertainty bought by the load disturbance and the nonlinearity of armature reaction simultaneously. The simulation results show that DC motor speed system has good performance in the dynamic and static accuracy.