Performance enhancement of inverted pendulum system by using type 2 fuzzy sliding mode control (T2FSMC)

The drawbacks of using FSMC when controlling the position motion on a non linear inverted pendulum system are the chattering problem and the robustness against parameter uncertainty and disturbances. This paper consider about the implementation of Fuzzy Type 2 in combining with SMC (T2FSMC) to enhance the ability of FSMC to overcome both of those problems. To be more optimally damp the oscillation, the range of fuzzy membership is determined based on the minimum ITAE (integral of time absolute error) value while the rule is constructed based on the product between the sliding surfaces and its derivatives. To enhance robustness performance against disturbances and parameter uncertainties, the range of non crisp membership value (footprint uncertainty) of Fuzzy Type 2 is determined by considering the minimum sum of ITAE values at several conditions with different plant parameter. It is proved from the simulation that the proposed method can solve chattering problem more effectively and also more robust against disturbances and parameter uncertainties than T1FSMC.