Variable universe adaptive fuzzy sliding mode control strategy for uncertain chaotic systems

Based on integrating the property of sliding mode control (SMC) with the thought of variable universe in adaptive fuzzy control, a design method of variable universe adaptive fuzzy sliding mode control (FSMC) strategy for uncertain chaotic systems is proposed. There are two sets of control rule bases. The first set is utilized to approach the equivalent control of SMC. By adjusting the universes of input variables and the membership fuzzy controller of conclusion part in rules on-line, a variable universe adaptive fuzzy control is developed to estimate the equivalent control. The derived adaptive law is applied to adjust the rule parameter for changing the control rules to meet system dynamic. Another set is used to attenuate the switching control of SMC in the sense of heuristic, which ensure the requirement of system stability. The Lorenz chaotic system is used to test the proposed control strategy and the simulation results show that this strategy is feasible and effective for chaos control.