Robustness analysis of a PI controller for a hydraulic actuator

•A linearized model for a Hydraulic Servo-Actuator is presented.•33 set parameters are identified for 33 set points.•The variability on these parameters is considered as the parametric uncertainty of the model.•PI controller was applied to a Hydraulic Servo-Actuator.•Small Gain theorem is used to analyze the robustness of the system with a classic PI controller.

In this work the authors address the problem of robustness of the classic PI controller implemented in a Hydraulic Servo-Actuator (HSA), by presenting a strategy based on the definition of a linear model of the system and the identification of its parameters for different working points. The variation of these parameters is considered as a measure of parametric uncertainty of the linear model. These uncertainties along with the definition of a nominal plant are used to analyze the robustness of the system implementing the Small Gain Theorem. Theoretical and experimental results show that a PI controller can provide robustness to the HSA.