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This paper describes the development of the octopus biology inspired OctArm series of soft robot manipulators. Each OctArm is constructed using air muscle extensors with three control channels per section that provide two axis bending and extension. Within each section, mesh and plastic coupler constraints prevent extensor buckling. OctArm IV is comprised of four sections connected by endplates, providing twelve degrees of freedom. Performance of OctArm IV is characterized in a lab environment. Using only 4.13 bar of air pressure, the dexterous distal section provides 66% extension and 380• of rotation in less than .5 seconds. OctArm V has three sections and, using 8.27 bar of air pressure, the strong proximal section provides 890 N and 250 N of vertical and transverse load capacity, respectively. In addition to the in-lab testing, OctArm V underwent a series of field trials including open-air and in-water field tests. Outcomes of the trials, in which the manipulator demonstrated the ability for adaptive and novel manipulation in challenging environments, are described. OctArm VI is designed and constructed based on the in-lab performance, and the field testing of its predecessors. Implications for the deployment of soft robots in military environments are discussed.

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Wound roll Electroactive polymer actuators fabricated with Dielectric Elastomer (DE) materials provide high bandwidth actuation for robots, minipumps, loudspeakers, valves and prosthetic devices. In this paper we develop a DE wound roll actuator fabrication process that produces high strain (13%), reliable (3480 cycles at maximum strain), and stiff (157 N/m) actuators. An axisymmetric Finite Element Method (FEM) model with electrostatic and radial bulk modulus nonlinearity predicts actuator displacement and stress. The maximum compressive radial stress occurs at the center of the innermost active layer. This layer also has the thinnest material, indicating the most likely failure point. The nonlinear model predicts actuator displacement in response to applied voltage and load, and matches experiments to within 1 mm 1

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