Dynamic models for trajectory survey and mapping of local physical fields of the ocean with autonomous underwater vehicle

摘要

Manifold AUV uses are viewed on the basis of the idea of ocean physical fields. An example is the problem of trajectory survey of the seabed field and navigation according to the bathymetric map. Application of known methods to the problems of AUV motion control runs into certain difficulties with regard to investigation of poorly known ocean areas. In this case representation of the field map does not define source data for control system, but defines the final goal of survey. Trajectory survey of physical fields of the ocean is based upon evaluating of state vector of an underwater vehicle and formulation of generalized reference points. Whereby search algorithm handles data about control field reducing the control problem to implementation and correction of program trajectory. An example would be organization of motion by bathymetric contour of seabed field. Information for control is produced on the basis of seabed profile measurements in longitudinal and lateral directions. Control algorithm simultaneously stabilizes depth and distance to the bottom, works out a course program and corrects it with provision for probable navigation errors. When organizing searching trajectories specific features of anomaly structure, including presence of natural background, time and spatial disturbances shall be taken into account. The control goal in the anomaly field consists in profiling of the area of certain range within searching zone. In general case several possible variants may exist. They differ on the type of motion trajectory and correction method when pointing at the anomaly source. In case of receipt of incomplete or unreliable information fuzzy logic is used for the modes of program trajectory correction. Motion control in all variants assumes combination of course correction with coordinate determination of anomaly feature points. A complex bathymetry problem is an indicative one among other certain problems. It includes search for local survey area, seabed mapping and profiling of anomaly area (bathymetric contour motion). The paper analyzes possible approaches to such and other similar problems addressing.