Design and Experimental Verification of a Model Based Compensator for Rapid Auv Depth Control

A model based autopilot for rapid depth control of an autonomous underwater vehicle is designed and installed in a small model experimental vehicle. The compensator is evaluated and verified by a series of experiments for a number of depth changing maneuvers. A systematic series of tests is performed to assess the effects of varying hydrodynamic parameters and control gains. The influence of the heave-pitch coupling is described in terms of the least squares fit of model to experimental open loop responses, which then form the basis of the closed loop antopilot design. The influence of sensor bias, parameter mismatch, and disturbances are discussed. The paper presents the design parameters of the small model vehicle and the presentation includes a video of the diving performance obtained when the compensator is properly designed. A conclusion is that control performance will be further enhanced by the incorporation of parameter adaption, as presented in a companion paper.