Abstract: For an electro-hydrostatic actuator (EHA)， the positioning accuracy is generally affected by uncertainties existing in the system. A robust position controller based on quantitative feedback theory (QFT) is proposed， which can describe the parametric uncertainties of human operators， master manipulator and environment in the templates for quantitative computation of the bounds and visualized adjustment between system stability and transparency， thus to improve the positioning accuracy of the bilateral-controlled EHA.Using this controller， four commonly used bilateral control schemes were tested based on an EHA test rig and a haptic device with force feedback. The verification experiments were performed in contact with soft and hard environments， which finally proved that the FR scheme was the most suitable for EHA remote control among the four due to its simple structure and excellent transparency.

Key words: bilateral control, electro-hydrostatic actuator(EHA), quantitative feedback theory(QFT), uncertainty, robust position control