“…To date, many different PID intelligent control methods have been proposed, based on sliding mode variable structure theory (Qiu et al , 2015), fuzzy theory (Qiu et al , 2015), neural networks (Cheng, 2015), genetic algorithms (Kanakis et al , 2018) and combinations of these (Chin and Lin, 2018), but most of these methods have assumed operation under ideal conditions and have ignored uncertainties and disturbances. Huang and Wang (2012), Kumar et al (2016), Kuo et al (2013) and others have proposed robust control methods for parameter uncertain systems based on interval polynomial theory. Bijani and Khosravi (2016) have proposed a robust PID control method based on H ∞ theory.…”