Abstract
Dielectric elastomer actuators (DEAs) are known as ‘artificial muscles’ due to their large actuation strain, high energy density and self-sensing capability. The conical configuration has been widely adopted in DEA applications such as bio-inspired locomotion and micropumps for its good compactness, ease for fabrication and large actuation stroke. However, the conical protrusion of the DEA membrane is characterized by inhomogeneous stresses, which complicate their design. In this work, we present an analytical model-based optimization for conical DEAs with the three biasing elements: (I) linear compression spring; (II) biasing mass; and (III) antagonistic double-cone DEA. The optimization is to find the maximum stroke and work output of a conical DEA by tuning its geometry (inner disk to outer frame radius ratio a/b) and pre-stretch ratio. The results show that (a) for all three cases, stroke and work output are maximum for a pre-stretch ratio of 1 × 1 for the Parker silicone elastomer, which suggests the stretch caused by out-of-plane deformation is sufficient for this specific elastomer. (b) Stroke maximization is obtained for a lower a/b ratio while a larger a/b ratio is required to maximize work output, but the optimal a/b ratio is less than 0.3 in all three cases. (c) The double-cone configuration has the largest stroke while single cone with a biasing mass has the highest work output.
Highlights
Soft robotics technology has drawn great research interest over the past two decades for its relatively low cost, safe human–robot interaction and application in confined or constricted environments
The results show that (a) for all three cases, stroke and work output are maximum for a pre-stretch ratio of 1 × 1 for the Parker silicone elastomer, which suggests the stretch caused by out-of-plane deformation is sufficient for this specific elastomer. (b) Stroke maximization is obtained for a lower a/b ratio while a larger a/b ratio is required to maximize work output, but the optimal a/b ratio is less than 0.3 in all three cases
We present the optimization in terms of both stroke and mechanical work output by varying the actuator geometry and pre-stretch ratio for three cases: (I) single-cone Dielectric elastomer actuators (DEAs) with a linear biasing spring; (II) single-cone DEA with a biasing mass and (III) antagonistic double-cone DEA
Summary
Soft robotics technology has drawn great research interest over the past two decades for its relatively low cost, safe human–robot interaction and application in confined or constricted environments (see e.g., [1,2,3,4,5,6]). DEA with a biasing mass has been shown to be able to generate a larger stroke compared to the one DEAs with the following three bias elements: a linear compression spring, a biasing mass and an antagonistic conical membrane with the same pre-stretch which creates a double-cone DEA. Two important simplifying assumptions are made in their models, which include a truncated cone-shape approximation and homogeneous stress distribution on the deformed DEA membrane Based on these modelling works, the effects of geometry and size on the performance of a conical DEA with a biasing mass was investigated in [25]. We present the optimization in terms of both stroke and mechanical work output by varying the actuator geometry and pre-stretch ratio for three cases: (I) single-cone DEA with a linear biasing spring; (II) single-cone DEA with a biasing mass and (III) antagonistic double-cone DEA
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