Robust fuzzy cascade control revised: Application to the rotary inverted pendulum

Fuzzy controllers are used in many practical applications since they guarantee impressive robustness properties and the control design requires only simple rules which are based on heuristic knowledge. However, since the number of rules is increased with the number of control inputs and measurements the control design may become overloaded and the design efforts even require more time than with classical approaches. To overcome this drawback this paper revises a comprehensive robust fuzzy cascade control strategy where all controllers are based on a uniform fuzzy set with a minimum number of rules. This approach represents an interesting perspective in education since the individual controllers need to be only calibrated with the scaling on their inputs and outputs. To show the efficiency and the robustness properties of the proposed control framework this fuzzy cascade design method is applied to Quanser's rotary inverted pendulum.