Dielectric elastomer actuator based mechanical counterpressure space suit cuff

Abstract Mechanical counterpressure (MCP) space suits could offer advantages over current gas-pressurized suits in safety, mobility, and decreased suit complexity and volume. However, a passive MCP space suit design poses challenges with donning and doffing as it must be exceedingly tight, requiring 29.6 kPa of MCP. Equipping the suit with wearable active devices, such as an expanding cuff, is a potential solution to this issue. These devices could allow the suit to loosen and tighten to aid in donning and doffing and to conform to changes in body geometry during movement. Dielectric elastomer actuators (DEAs) are a promising candidate for the active device element of an MCP space suit design due to their compliance, high energy density, long lifetime, and high bandwidth. The high voltage required to drive DEAs can be reduced by subdividing the dielectric layer of the DEA to create DEA multilayers (DEAMs). This work presents a DEAM-based MCP space suit cuff, a fundamental component of a full suit concept, that applies passive pressure through prestretch and loosens upon actuation for donning, doffing, and during movement. The cuff is fabricated using a batch-spray and stamp technique, and it consists of 24 active layers, each 200 µ m in thickness, giving the cuff a total thickness of 6 mm including inactive encapsulation layers. The final cuff design achieves an MCP of 19.52 kPa, a maximum pressure relief of 5.42 kPa, and a response time of 0.7 s. The proposed design can achieve a counterpressure of 29 kPa with a prestretch factor of 2.42. These results demonstrate the capabilities of DEAM-based wearable devices, introducing novel actuation functionality to wearable technology.