A hybrid pneumatic electrorheological valve based on air–liquid interface

This study presents a hybrid pneumatic electrorheological (HPER) valve based on an air–liquid interface for electrically tunable pneumatic pressure regulation without mechanical actuation. In the proposed configuration, giant electrorheological fluid (GERF) functions as the electrically responsive control medium, while air serves as the working fluid. This separation combines the rapid, reversible field induced rheological response of GERF with the low flow resistance and efficient power transmission of pneumatic actuation. The valve was characterized under a constant air injection rate by varying the electrode gap and the electric field strength. The results show that the pressure regulation capability increases with electric field strength and decreases with electrode gap. The valve length, electrode gap, and width are given as l = 10 mm, h = 8 mm, and w = 5 mm, respectively, while a maximum controllable pressure drop of 37.3 kPa was achieved at an electric field strength of 1.0 kV mm − 1 . Compared with a liquid–liquid configuration using GERF as the working fluid, the air–liquid interface produced a larger pressure drop under the same geometric and electrical conditions while reducing GERF consumption. Finally, the HPER valve was integrated with a silicone soft gripper, which stably manipulated objects with different stiffness and fragility, including a rigid 3D printed cylinder and a fresh blueberry, without observable damage. These results demonstrate that the proposed HPER valve is a compact, electrically controlled pneumatic regulation element with strong potential for integrated soft robotic systems.