Adaptive fuzzy sliding mode control for large erection mechanism

Erection mechanism adopts electro-hydraulic proportional valve to control telescopic cylinder. Electro-hydraulic system is a complicated system suffering from nonlinearities, uncertainties and disturbances. It is difficult to establish mathematical model and perform a high precision control using linear control methods. Sliding mode control (SMC) is robust to parameter variation but the accurate system function should be derived. In this study, adaptive fuzzy sliding mode control algorithm was designed to control the position of large erection mechanism. Fuzzy logic system was utilized to approximate the unknown system functions. The robust adaptive law was proposed to reduce the errors between true functions and fuzzy approximators. The stabilities of control schemes were proved in the sense of the Lyapunov stability theorem. Hydraulic model was established in AMESim software and controller was implemented in Simulink software. Union simulation results verify that the proposed control system can achieve favorable tracking performance for erection mechanism and robust with regard to parameter variations and external load disturbance.