“…Hence, the typical fuzzy PID controllers cannot adapt for a wide range of working environments with large variation of perturbations [18]. As a result, other control techniques such as robust control, intelligent theory, or estimation methods are needed to combine with the fuzzy PID to overcome this weakness [14][15][16][17][18][19][20][21]. Among them, fuzzy PID combined with neural network and grey predictive techniques is a feasible solution.…”