Meeting Abstract
Last year we showed that by bilaterally attaching soft robotic actuators (pneunets) to a flexible passive foil, we could construct an active swimming model for fish locomotion called the ‘pneufish’. Pneunets consist of a series of connected, segmented chambers molded from Smooth-on Dragon Skin silicone 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. We assembled pneufish and suspended them in a recirculating flow tank attached to an ATI 6-axis force-torque sensor. We measured thrust, lateral forces, and amplitude of trailing edge oscillation and investigated the swimming performance of the model at a variety of frequencies, flow speeds, foil stiffnesses, and air pressures. A brief exploration of the available parameter space revealed that the pneufish generated positive thrust and undulatory propulsion only at certain parameter combinations – namely, high activating air pressure and low undulatory frequency. An improved digital pressure regulatory system shows that the model can achieve realistic propulsion across a larger variety of parameter combinations. Changing the minimum pressure level in the pneunets does not significantly affect performance, but changing the amount and frequency of air injection into the pneunet does. Additionally, we have expanded the model from a simple two-pneunet apparatus (duo-pneufish) to a four-pneunet apparatus consisting of two consecutive pneunets on each side of the foil (quad-pneufish), and plan future experiments to evaluate the performance of this multi-segmented system that is more fish-like.
