Design and test of an improved active disturbance rejection control system for water sampling unmanned surface vehicle

Unmanned surface vehicles (USVs) have wide application prospects in military and civil fields. Motivated by the large demand for environmental protection equipment, a water-sampling USV (WS-USV) system is designed in this study. The software and hardware of the entire system are designed and developed independently. Two water sampling modes, a manual remote control mode and remote interface automatic control mode are designed for handling emergencies. The WS-USV is propelled by twin-propellers. These propellers have many input constraints owing to their inherent structure, making the design of the controller very difficult. In this study, an improved active disturbance rejection control (ADRC) method is proposed and a saturation function is introduced to design a path-following control system for the WS-USV. This enhances the anti-disturbance ability for addressing environmental disturbances by wind, waves and currents in the water sampling process. The stability of the system is improved. The feasibility, stability and performance superiority of the control system are proven by water sampling contrast experiments.