Depth-Changing Motion Control of Under-Actuated Autonomous Underwater Vehicle Based on Prescribed Performance Control

To address the depth control accuracy of an autonomous underwater vehicle (AUV) under unknown disturbances, our study proposes an anti-jamming depth-tracking method based on prescribed performance control. By defining constrained performance functions, we designed a prescribed performance control (PPC) backstepping controller to enhance the tracking control performance for the vertical plane motion of the under-actuated AUV. Additionally, nonlinear disturbance observers (NDOs) are integrated to precisely compensate for unknown disturbances. An adaptive law with “σ-modified leakage terms” is also introduced to estimate the bounds of these disturbances, enabling adaptive backstepping disturbance rejection control and improving both the transient and steady-state depth control performance of the AUV. Simulation results using a MATLAB/Simulink model demonstrate the accuracy of the proposed mathematical model. The adaptive inverse controller, designed with prescribed performance criteria, aligns perpendicularly to the AUV's motion, providing high control performance along with stable and effective transient behavior.