Tracking control of a remotely operated underwater vehicle with time delay and actuator saturation

Human-in-the-loop (HITL) system is referred to as a promising technology to extend human actions and intelligences to deep ocean. Many applications of HITL demand the remotely operated vehicle (ROV) to track a desired target point. However, the cyber- and physical-constrained characteristics on ROV make it challenging to achieve the tracking task. This paper is concerned with a tracking control problem for the ROV, subjected to time-varying delay in cyber channels and actuator saturation in physical channels We design a model-free proportional-derivative (PD) controller to enforce the position tracking of ROV. For the proposed controller, Lyapunov-Krasovskii functions are constructed to analyze the stability, and then the sufficient conditions are provided to show that the tracking controller can stabilize ROV. In order to estimate and optimize the domain of attraction (DOA), the stability conditions are rearranged into a form of linear matrix inequalities (LMIs), through which the required initial stability conditions can be developed. Finally, simulation and experiment results are performed to validate the effectiveness. It is demonstrated that the designed tracking controller can guarantee asymptotic stability, while the DOA in this paper can be significantly enlarged as compared with the other ones.