Investigations of a spherical dielectric actuator

Low-cost, simple and robust actuators are important for emerging robotics technologies. In this thesis, a hyperelastic spherical dielectric elastomer actuator (DEA) was fabricated out of BJB TC-5005 and tested to determine its feasibility as an actuator. The mechanics of the actuator were modelled analytically using an Ogden material model for large deformations. The electrical actuation mechanism was also derived. A seamless spherical DEA with an external radius of 30.65 mm was inflated, recording the expansion with and without actuation potentials. The hysteresis upon inflation and deflation of the spherical DEA was also investigated, and a pressure difference of 65Pa was recorded. The force output of a sandwich-type compression of the sealed spherical DEA was measured with different actuation potentials and compression distances. The sandwich-type compression is suitable as an actuator as it showed a 3% change in height when inflated to 817 Pa and loaded from 2 to 6 N.