Robust Tuned Controller Based on Interval Type 2 Fuzzy Logic for Robotic Manipulators Exposed to Perturbations and Parametric Uncertainties

Abstract

Industrial robotic arms require a reliable ability to operate in the presence of unexpected perturbations. In this paper, control of a robotic arm is contemplated in the presence of parametric uncertainties which are coupled by significant external perturbations. The proposed method is based on tuning of the higher-order sliding mode controller parameters by the interval type 2 fuzzy logic. Initially, the common chattering effect of the classic sliding mode is eliminated by using higher-order SMC and saturation function, which makes it more robust than the classic algorithm. However, the high-order sliding mode still cannot deal with strong external perturbations properly. This issue is addressed by combining the algorithm with fuzzy type 2 membership functions which add the self-tuning feature to the controller. Simulations show the superiority of the proposed controller over the classic and the higher-order sliding mode controllers in dealing with various significant perturbations.