Raise Damping in Electro-Hydraulic Systems with Observed Pressure

Abstract

The growing interest in energy efficiency points the research for hydraulic systems to electro-hydraulic drives, specifically hydraulic actuators directly coupled to pumps driven by electric motors. This design eliminates functional energy dissipations and enables energy recovery but leads to inherently low damping. The consequence is that harmful payload oscillations deteriorate the position control's accuracy of the actuator. Therefore, raising the drive damping via pressure feedback is crucial and requires knowledge of the pressure in both actuator chambers. This paper investigates using pressure observation to that end (i.e., a virtual pressure sensor implemented via software replaces two physical pressure transducers). High-passed pressure feedback is introduced using a model-based design for setting up closed-loop position control. This approach is simulated numerically on a heavy-duty robotic manipulator. The results confirm that the payload oscillations are significantly reduced without affecting position tracking.