Transient Motions and Static Poses in Soft, Viscous-Driven Actuators

In this paper we further studies of viscous-driven fluidic elastomer actuators. Specifically, the one we investigate here consists of simple elastomer bellows connected in series by slender tubes and arranged in two columns around a neutral plane. The slender tubes and wide bellows configuration result in advective-diffusive flow, which causes non-uniform pressure distributions throughout the actuator and, as a consequence, complex transient 2D deformations that depends only on the shape of the input pressure profile, rather than multiple pressure sources and/or valves. We extend upon previous work by demonstrating and modeling a three-finger 'manipulator' capable of stabilizing a computer mouse and operating its scroll wheel. This demonstration illustrates the interplay between in-put pressure gradients and motion output, and additionally how a single valve can further enable stationary poses throughout the workspace of the actuator. To further illustrate how the motion is affected by the input pressure gradients, we perform a frequency sweep using our model. This type of embodied control matches well the infinite passive degrees of freedom afforded by the soft material, and holds great promise for future applications in soft robotics.