Meeting Abstract
Underwater walking is the fundamental predecessor in the evolutionary transition from water locomotion to land locomotion. Underwater walking is still used by a wide range of species to move in the benthic freshwater and marine environments. Underwater walking involves a unique mix of forces seen in both swimming and terrestrial walking. Being submerged in water, these animals encounter hydrodynamic and hydrostatic forces such as buoyancy and drag. Like terrestrial walking, propulsive force is generated via substrate interactions, but must overcome the addition of hydrodynamic drag in spite of lower effective body weight due to buoyancy. Due to the lack of a sufficiently sensitive force measurement system, little is known about the substrate reaction forces of underwater walking. This poster describes the design and fabrication of an underwater force plate that can sense small propulsive forces the underwater walking animal applies to the substrate. Similar design to a terrestrial force plate, this underwater force plate is 3D printed using stereolithography and equipped with strain gauges in a Wheatstone bridge configuration, the signals from which are amplified by approximately 4600x. Preliminary calibrations on a uniaxial system showed calibration constants of 5 mV/mN, with a minimum detectable force of 2 mN. The underwater force plate will allow for the investigation of habitat and substrate differences compared with various morphology that utilize underwater walking. Understanding how these animals interact with the substrate and the hydrodynamic environment will provide insight in the evolutionary transition from water to land.
