Adaptive fuzzy switching control based on sliding mode for hydraulic servo system of rolling mill

In view of the nonlinearity and parameter jump caused by the conversion of structure in rolling mill hydraulic servo system, a direct adaptive fuzzy controller based on sliding mode control is designed. Firstly, sliding mode function and control law are designed. Secondly, the direct adaptive fuzzy controller is constructed to approximate the total unknown terms in the control law, and the stability of the system is analyzed and proved through the Lyapunov function, we obtained the system is asymptotically stable. In addition, in this paper the optimal performance index is considered as the rule of switching control which can implement the effective switching among sub-models controller. Finally, the simulation results demonstrate that the designed controller can not only reduce the high frequency chattering effectively but also have good robustness for the system uncertainty and parameter perturbation.