| Paddle-wheel-propelled ships have the advantages of small turning radius,shallow draft and not easy to be entangled.It is a good working platform for application scenarios such as emergent plant cutting,water weed cleaning,water surface cleaning,and aquaculture.Unmanned ships do not require staff to work on site,can ensure the safety of personnel,and do not need cockpits and some living facilities,which can save a lot of space,and unmanned ships are developing in the direction of intelligence.There are many technologies involved in the development of wheel propulsion of surface unmanned ships.Among them,trajectory planning is related to the efficient operation of paddle steamers,and trajectory control is related to the autonomous work of paddle wheels to propel surface unmanned ships.Therefore,it is of practical significance to study the trajectory planning and trajectory control of the surface unmanned ship propelled by paddle wheels.Combining the work characteristics of paddle steamers to plan the trajectory and realizing the automatic trajectory control of paddlewheel propulsion unmanned ships are the basic research contents of this article.Based on the distance and azimuth information,spherical formula and geometric relationship between two points contained in the simplified water contour map,high-precision point-to-point trajectory planning can be achieved in a small area of water.By analyzing the kinematics and dynamics of paddle steamers,an indirect trajectory control scheme including PI speed control and discrete sliding mode heading control with interference compensation is proposed for paddle steamer trajectory control.The main research contents of this thesis are as follows:Firstly,starting with path planning,considering the actual needs and operating environment of paddle steamers,the realization method of point-to-point paddle steamer trajectory planning is analyzed and the feasibility of the method is verified.Based on GaussKrüger projection and vector operation,a method to obtain the track route of full coverage of the water area is given.Secondly,after analyzing the influence of interference force and paddle wheel propulsion on paddle steamer navigation in the hull coordinate system and inertial coordinates,the mathematical model of paddle steamer motion is established,the trajectory control scheme of the paddle steamer is designed,and the trajectory control algorithm is verified by simulation.Thirdly,build a paddle steamer mechanical platform for trajectory control experiments,and build a hardware platform based on Loongson 1C and a shipboard control system software platform based on RT-Thread according to the overall design of the trajectory control system,and design shore-based control system software.Based on the actual ship test of the built platform,the control effect of the paddle steamer trajectory control method is verified and the test results are analyzed and summarized.Regarding the planned trajectory route as the target route,the maximum trajectory error of the paddle steamer’s straight-line tracking in the water test is within 1m.The rotational speed of the left and right paddle wheels changes smoothly during the straight-line trajectory tracking,and the paddle steamer sails smoothly. |
