Application Research Of Advanced Control Theory In Control System Of Cold Rolling Temper Mill

The Temper mill is the key equipment for the production of high quality cold rolled strip and it plays an important role in the metallurgical production process.Its purpose is to eliminate the yielding platform of the strip after annealing,to improve the shape quality of the strip,the smoothness and roughness of the strip surface.The cold rolling process is a typical multivariable coupling and complex nonlinear control system,and there are problems such as uncertainty and random disturbance.The application of classical control theory is difficult to achieve the goal of global optimization and high precision control.Therefore,the main purpose of this paper is to utilize some advanced control technology to deal with the aforementioned problems.The main work and innovations of this paper are listed as follows:Firstly,a simultaneous robust,decoupled output feedback control approach for multivariate industrial processes with parameter uncertainties is proposed.Based on the desired control performance indicators,the expected transfer function of the closed-loop multivariate system is configured as a nonsingular diagonal matrix.Using coprime factorization theory,the weighting functions are selected and the parameterization matrix and controller are designed and calculated to achieve simultaneous,robust,decoupled control that takes into consideration parameter uncertainties.The performance and effectiveness of the proposed approach is demonstrated using a case study based on the crown-thickness control system of the hot strip mill processes.Secondly,a parameter tuning approach for a second-order linear expansion observer with different poles is proposed.The frequency domain method is used to study the estimation ability of linear extended state observer(LESO)using differential tracker.The observation error and convergence of the LESO parameters theoretically prove the closed-loop system stability..The purpose is to further solve the problem of multi-variable coupling,multi-parameter difficulty setting and non-linearity of flat plate thickness.The simulation comparison with the PID controller shows that the controller has good performance on the external disturbance rej ection with the consideration on parameter uncertainties.Thirdly,in order to solve the high precision problem of AC motor in the tension winding of the flat machine,a three-phase current source inverter passive-based control(PBC)strategy based on interconnection and damping assignment(IDA)is proposed.Firstly,the three-phase current source inverter(CSI)with independent storage unit under lumped parameters is modeled,and the port-controlled hamiltonian(PCH)model of three-phase CSI in Park coordinate system is proposed.By solving the parametric partial differential equations of the interconnection and damping matrix under the closed-loop system,the control rate of the system is obtained and the Lyapunov stability of the system is analyzed.Through the simulation experiment of the proposed control strategy,the results show that the three-phase current source inverter has strong anti-disturbance ability,thus improving thecontrol performance of the system..Finally,aiming at the tension control system of the flattening unit coiler of cold strip mill process,a segmented multi-model switching adaptive control method is proposed to solve the electromechanical time parameter in the tension system model caused by the change of the coil diameter of the coiler.Firstly,the tension system object model is analyzed.The segmented multi-model structure,multi-model switching mechanism,adjuster parameter adaptive algorithm is designed.The simulation research and field test resultsare showed and proved its effectiveness.