Meeting Abstract
Previously at SICB, we introduced the “pneufish,” a soft robotic fish model with two actuators (pneunets) attached to a flexible passive foil. Pneunets consist of a series of connected, segmented chambers molded from silicone rubber, that can be pressurized. When pressure is increased, each chamber expands and pushes against its neighboring chambers, resulting in a net lengthening and curvature of the pneunet. Attaching a pneunet to each side of a flexible foil ‘backbone’ creates an actively controlled swimming fish model via programmed digital pressure regulators. Assembled pneufish were suspended in a recirculating flow tank, attached to an ATI 6-axis force-torque sensor, and we measured thrust, lateral forces, and the amplitude of trailing edge oscillation during locomotion. Pneufish were activated pneumatically using a large range of parameters, focusing on frequency, water flow speed, maximum and minimum air pressure, and foil stiffness. Results showed strong interactions between stiffness and frequency, while frequency on its own had a rather small effect on performance. We then expanded the pneufish model to include four pneunets, arranged in pairs sequentially down the foil, to make the “quad pneufish” model. Using this quad pneufish apparatus, we continued to investigate the model’s performance across a parameter space, adding activation phasing, differential air pressure between front and back pneunet pairs, and the effect of pneunet orientation on the model’s performance. These additional parameters allowed us to investigate the performance of different activation patterns in a more complex biomimetic fish-like model, allowing the quad-pneufish apparatus to be used as a model for investigating the effect of different patterns of body deformation on aquatic propulsion.
