Adaptive path-following control for high-underactuated underwater glider under hydrodynamic coefficient uncertainties

Underwater gliders (UGs) play a prominent role in collecting data within a specific underwater depth range. Due to the unmanned nature of these vehicles, the path-following control significantly influences their other systems and energy consumption. In this study, the performance of the path-following control was improved under hydrodynamic coefficient uncertainties using the adaptive control structure. The main control system, using the adaption law, autonomously updates itself to mitigate the adverse effects of uncertainties. The stability of the control law was proven through the utilization of a Lyapunov-function candidate. In the study, we take into account uncertainties in hydrodynamic coefficients, actuators, and position and orientation estimation. The impact of uncertainties on performance was investigated using the Monte Carlo simulation technique, which stochastically selected parameters. The results ultimately demonstrate that the uncertainties adversely affect the control of states. However, the adaptive structure exhibits robust performance compared to traditional controllers such as PID and LQR controllers with fixed gains. The adaptive path-following control structure reduced actuator usage, leading to decreased power consumption by the controller. Furthermore, the proposed structure was involved in an experimental case study, which was tested in a pool to validate its performance.