Controlling a Fishing Net Geometry Underwater Using a Data Assimilation Method

Abstract

We propose a control method that changes the geometry of a fishing net into an arbitrary geometry. To control the net geometry, an automatic control system was constructed by integrating the data assimilation method into a fishing net dynamics simulation. This study focused on the function of the data assimilation method to estimate the unknown parameter needed to control the net geometry. By applying the parameter estimation, the length of the material and loading were set as unknown parameters and estimated to be an intended geometry of the fishing net. Further, geometry control experiments consisting of numerical simulations were conducted for validation. This was achieved by using a simplified plane net model and a trawl net model. An automatic control system using the extended Kalman filter was applied. In addition, we confirmed that the net geometry can be controlled in real space by the automatic control system. For validation, the results of experiments conducted in an experimental flume tank were compared with the numerical simulation results of the plane net geometry by using the automatic control system that integrated an ensemble Kalman filter. The numerical simulation results were found to be congruent with those of the flume tank experiments, confirming the validity of the proposed control system.