Design and Optimization of Interval Type-2 Fuzzy Logic Controller for Delta Parallel Robot Trajectory Control

In the view of the problem of designing and optimization of interval type-2 fuzzy logic controller (IT2 FLC) for Delta robot trajectory control, a systematic design method is put forward in this paper. A type-1 fuzzy logic controller (T1 FLC) is designed and optimized. Then, three kinds of method to blur the T1 fuzzy membership functions are proposed to generate IT2 fuzzy sets from the optimized T1 fuzzy sets. A systematic analysis is carried out to study the relationship between blur methods, blur degree and output control surface of IT2 FLC. Output signal enhance coefficient is proposed to make sure the IT2 FLC to provide enough output signal. The optimized IT2 FLC is validated through a set of simulations and by comparing against its type-1 counterpart in the presence of external and internal uncertainties. The simulation results show the optimized IT2 FLC can provide better trajectory tracking performance.