Meeting Abstract

S5.6  Wednesday, Jan. 5  Testing Biomimetic Structures in Bioinspired Robots LONG, JH*; HIROKAWA, J; ROBERTS, S; KRENITSKY, N; FRIAS, C; DE LEEUW, J; PORTER, ME; Vassar College jolong@vassar.edu

The mechanical design of a biological system is understood in the context of the functioning organism. Live organisms, however, come with practical constraints: complexity, variability, and transience. To overcome these constraints, many researchers employ a new kind of physical model for biomechanical testing: self-propelled robots using biomimetic structures. As the shape, size, or mechanical properties of the structure are varied, the response of the robot is measured as a change in locomotor performance or behavior. Working with robots, researchers gain control over motor outputs and physical properties. This experimental control allows for stronger inference of the causal mechanisms connecting structure, mechanical properties, and locomotor performance. As an example, we present MARMT (Mobile Autonomous Robot for Mechanical Testing), a surface-swimmer that undulates a submerged biomimetic tail to power cruising and accelerations. Our goal was to determine how vertebral column morphology, the number of vertebrae, specifically, influences swimming performance. We built biomimetic vertebral columns using hydrogels outfitted with a variable number of rigid ring centra. We changed MARMT’s tail-beat frequency, amplitude, and behavior. MARMT’s locomotor performance was measured using an on-board accelerometer and external video. At high tail-beat frequencies, the number of vertebrae positively correlated with increases in acceleration during fast-starts. Since the number of vertebrae increased the flexural stiffness of the biomimetic vertebral column, we conclude that acceleration performance is enhanced by the increased stiffness afforded by vertebrae. This work was supported by NSF DBI-0442269 and IOS-0922605.