Abstract: The engineering application of balloon actuators is restricted due to such problems as the lack of uniformity in membrane thickness, leakage of compressed air, rigid substrate, and the lack of a control theory. To overcome those problems, several measures are developed. The improvement of membrane manufacturing process results in a drastic decrease in thickness variation. A novel fabrication process without the adhesive procedure is developed to improve the air-tightness performance of balloon actuators. Flexible material is used as substrate of balloon actuators to enable them to bend easily and be mounted on various surfaces of airfoils. The deformation of the elastic membrane of balloon actuators is analyzed using the Mooney-Rivlin hyper elastic model so that the relationship between the pressure load and deformation of the elastic membrane is characterized in theory. The analysis indicates that width is the main factor for the deformation of elastic membrane in the same condition, and it also provides a theoretical basis for the control of balloon actuators. The experiment results demonstrate that the balloon actuators can be used for separation delay and drag reduction to realize active flow control.

Key words: balloon actuator, active flow control, flexible structures, fabrication process, membranes, deformation