Design, fabrication and modeling of a dielectric elastomer tridimensional minimum energy structure for space mission

Facing increasingly complex on-orbit servicing missions, soft grippers and manipulators are showing favorable opportunity to capture and manipulate targets safely. Among multiple soft-gripper actuation techniques, the dielectric elastomer actuator (DEA) shows superior application prospects for on-orbit missions as it can directly respond to voltage stimulation. However, small load capacity limits the further practical use of DE grippers. In this paper, a novel design of dielectric elastomer tridimensional minimum energy structure (DE-TriMES) along with its analytical model are proposed. This DE-TriMES design features pre-stretched DE film and elastic frame positioned in different planes. Analytical model points out that, by elevating the DE film from the elastic frame, DE-TriMES can effectively enhance its load capacity along with the tip stroke. Both multiphysics finite element simulation and experimental tests are carried out to verify the design and its model. Considering the space environment constraints, fabrication scheme of DE-TriMES finger prototypes is carefully decided. Conductive silicone and screen-printing technique are utilized to form thin and steady electrodes and selective laser sintering (SLS) technique is utilized to realized complicate but unimorph frame. The experiments verifies that this design can lead to high load capacity and outstanding specific force output, which indicates a favorable vision for further developing tridimensional DEMES design.