Time Delay Control of an AUV with Unknown Dynamics Using Position Measurements

In this paper, a control system is designed for dynamic positioning of an AUV with unknown dynamics, subject to external disturbances and without velocity measurements. The uncertainties and external disturbances are compensated for by online estimation based on time delay estimation method. To obtain AUV velocities, a robust exact differentiator is considered such that high sampling rates for velocity measurements are guaranteed and the dependence of controller to DVL data is removed. The controller is considered as a nonlinear PD-type controller together with feedforward of estimated dynamics and disturbances. In order to evaluate the performance of the proposed control system, simulations are conducted. Besides, comparisons are made with recent works to validate the performance of the proposed control system. Simulations show high accuracy and superior performance of the proposed control system compared to other controllers.