“…Hydraulic systems have been extensively employed in sundry industrial applications by utilizing the advantages of large force/torque output capability and small size-to-power ratios, such as automotive active suspensions (Huang et al, 2018; Ma et al, 2019; Sun et al, 2015), hydraulic load simulators (Kang et al, 2018; Wang et al, 2018; Yao et al, 2013), robots and manipulators (Chen and Fu, 2015; Montazeri et al, 2017), aircraft actuators (Sente et al, 2012), and so on. However, the existence of various modeling uncertainties and high nonlinear behaviors make it complicated for developing high-performance closed-loop controllers (Yang et al, 2017).…”