Modeling and Estimation of Hydrodynamic Potentials1

In order for underwater vehicles to fully realize the potential of utilizing oscillating foils as propulsion mechanisms, it is necessary for the control scheme to be aware of the state of the water environment, especially the vorticity in the water. In this paper, we investigate the problem of estimating the hydrodynamic potentials based on pressure measurement on a submerged body. A relationship between hydrodynamic potential and pressure distribution on the foil based on potential flow theory is obtained. This relationship is then reformulated to eliminate the dependence on acceleration of the submerged body which is not available. Based on this relationship, estimation algorithms for the vorticity of the water using pressure measurements on the submerged body are derived. Simulation studies demonstrate the efficacy of the estimation scheme in both ideal and some non-ideal situations.