Finite-time Control For USV Path Tracking Under Input Saturation With Random Disturbances

With the implementation of the strategy of maritime power and the continuous development and utilization of marine resources,the research of marine equipment is also deepening.In the complex ocean interference,designing a reasonable control algorithm to realize the tracking control of unmanned surface ships is an important prerequisite for unmanned surface ships to successfully perform scientific research and exploration,patrol search and rescue tasks.In order to improve the accuracy of path tracking control algorithm,describing the wave disturbance model that is more in line with the actual sea conditions is one of the important research contents of the path tracking control.The main research contents of this thesis are as follows :1、The wave is the most important factor affecting the motion control of unmanned surface ships.Firstly,the wave disturbance is analyzed.Based on the actual non-white noise in the marine navigation environment,the non-white noise is used to reasonably describe the wave disturbance.Then,the main wave force components affecting the ship motion control are analyzed.It is found that the second-order wave drift force is the main interference affecting the ship motion control.Then a backstepping controller with non-white noise to describe the second-order wave drift force is designed to realize the accurate description of the wave disturbance.The stability and effectiveness of the designed control algorithm are verified by simulation,which can realize the tracking of the desired trajectory and speed under random noise interference.2、On the premise of describing wave interference based on non-white noise,finite-time control is introduced to improve the control performance of path tracking considering the background of efficient and accurate maritime rescue missions.Through input saturation control,the maximum force value provided by the ideal controller and the actual propeller is different,and the excess part is appropriately compensated.The dynamic model of the unmanned surface ship is appropriately supplemented.The input of the dynamic model is transformed into the input under input saturation control.A finite-time backstepping control algorithm with input saturation is designed to improve the applicability of USV path tracking.The simulation is compared with no input saturation and finite time,no finite time,no finite time and random noise disturbance and no noise suppression interference.The simulation verifies the effectiveness and applicability of the proposed controller algorithm.