Research On Path Planning And Motion Control Optimization Algorithm Of Underactuated Unmanned Ship

In recent years,with the development of the ocean industry,the understanding,development,and protection of the ocean have received increasing attention.Ships,as the most important means of maritime transportation for humans to care about,understand,and operate the ocean,have an extremely special strategic position.Unmanned ships have always been a hot topic in the research of ships.Among the many key technologies in the research of unmanned ships,the path planning and motion control issues of unmanned ships have become cutting-edge topics of great concern in the field of unmanned ships.This thesis takes the underactuated unmanned ships as the research object,and studies the mathematical model establishment,path planning,and path tracking control issues of the underactuated unmanned ship.The specific research work is as follows:(1)Considering the state variables and conditions that may be involved when an underactuated unmanned ship navigates in a water environment,the mathematical model of the underactuated unmanned ship is described.Firstly,a 3-degree nonlinear kinematics and dynamics model of the underactuated unmanned ship is established;Secondly,considering the follow-up motion control law design and controller research,from a control perspective,taking the input rudder angle as the control variable and the heading angle as the output vector,the response mathematical model of the underactuated unmanned ship is established;Finally,considering that unmanned ships may be interfered by the external environment during navigation,mathematical models of wind,wave,and current interference are established and introduced into the dynamic model,laying a mathematical foundation for subsequent path tracking research.(2)Unmanned ships need path planning to conduct autonomous navigation operations.This thesis proposes an improved sparrow search algorithm based path planning method for unmanned ships.Firstly,Cubic chaotic map is used to initialize the population,replacing the random generation method of traditional algorithms;Secondly,in the late iteration stage of the algorithm,the fitness standard deviation is introduced to determine whether the population has fallen into a local optimum,and a Gaussian random walk strategy is used to perturb the optimal individual,assisting the algorithm in escaping the local optimum and obtaining the optimal fitness value;Then,the selected water environment is modeled,and the original electronic waterway map is subjected to operations such as information preprocessing,rasterization,and obstacle expansion processing;Finally,an improved algorithm is introduced into the processed electronic channel map and a path planning simulation experiment for unmanned ships is conducted to verify the effectiveness of the proposed algorithm.(3)After obtaining the planned path,unmanned ships are required to track the target path.Addressing the path tracking problem of underactuated unmanned ships,this thesis proposes an adaptive sliding mode control algorithm for path tracking of underactuated unmanned ships.Using adaptive sliding mode control to design the longitudinal propulsion force control law and steering torque control law;Using a double power function as a reaching control law to suppress chattering caused by sliding mode control;A parameter adaptive law with a correction term is designed to observe the boundary value of time-varying disturbances in unknown external environments,and system stability is demonstrated.Finally,linear path tracking and circular path tracking simulation experiments were conducted on the proposed algorithm in MATLAB.The simulation results showed that the unmanned ship can quickly and accurately track the target path,verifying the effectiveness of the proposed algorithm.(4)In order to verify the feasibility of the designed path tracking algorithm for the control of an actual unmanned ship,an underactuated unmanned ship embedded motion control system was designed,and the system hardware and software were designed,with emphasis on the main hardware circuit design work.After completing the integration and debugging of the system,a path tracking experiment was conducted on the JUST-002 boat equipped with the embedded control system mentioned in this article,and the straight path and curve path were tracked respectively.The experimental results prove that the designed control system and path tracking algorithm can effectively control the motion of an underactuated unmanned ship.Finally,combined with specific functional application scenarios,the designed embedded motion control system is deployed on an YL-2500 unmanned ship to conduct autonomous cleaning of water surface garbage in the river.The unmanned ship performs cleaning operations while tracking the path.The actual cleaning effect is significant,verifying the good effect of the algorithm and system in practical projects.