Attitude Control And Path Optimization Of Underwater Glider

Underwater glider is a kind of special underwater sampling robot,which has the advantages of low manufacturing cost and long endurance,etc.,and is suitable for underwater observation tasks of large scale range and long working cycle,which meets the actual needs of diversified exploration of the ocean by human beings.Due to the special working principle and movement mode of underwater glider,it is more sensitive to environmental factors in practical application.Therefore,the research on the path planning of underwater glider is one of the key technologies to ensure that it can successfully complete the ocean observation task.In this thesis,the Hybrid-driven underwater glider is taken as the research object.In order to improve the operating characteristics of the underwater glider,the steady motion analysis of the underwater glider is carried out on the basis of the establishment of its dynamic model and the design of the pitch switching controller is carried out.Finally,considering the motion characteristics and energy consumption efficiency of underwater glider,the path planning of underwater glider is carried out based on particle swarm optimization algorithm.The main research contents and achievements include the following aspects:1.The dynamic model and numerical simulation of a Hybrid-driven underwater glider are presented.This model takes into account the control effect of buoyancy adjustment mechanism,pasture adjustment mechanism and propeller,the mass and position information of each mechanism,and the hydrodynamic force of the glider in the fluid medium.Based on the dynamic model,the two working modes of the Hybrid-driven underwater glider are simulated and analyzed respectively,and the results accurately describe the two movement modes of the Hybrid-driven underwater glider.2.Based on the dynamic model of the underwater glider,the steady state motion equation of the underwater glider in the longitudinal profile was derived,and the relationship between the pitch motion state of the underwater glider in the longitudinal profile and the parameters of the control mechanism was analyzed.The range of the control parameters in the steady state operation was obtained through simulation.According to the steady state motion,a backstepping controller is designed for the handover motion of the underwater glider,and compared with the traditional PID controller.Through simulation comparison,it is verified that the backstepping controller reduces the running time of the control mechanism in the process of large angle pitch transition of the underwater glider,which can realize faster angle conversion and is superior to the PID controller in dynamic performance.3.In view of the sawtooth trajectory of underwater glider,the path planning of underwater glider is carried out based on particle swarm optimization algorithm,considering the motion characteristics and energy consumption efficiency of underwater glider.According to the motion characteristics of the underwater glider and combined with the energy consumption problem of the underwater glider,the heading error,energy consumption efficiency and path risk of the underwater glider under water were selected to develop the fitness function.Finally,a nonlinear dynamic adjustment strategy based on inertia weight is selected to improve the global searching ability of the algorithm.Through simulation comparison,it is shown that the optimized algorithm can generate higher quality path,and can converge to the global optimal in fewer iterations,which effectively improves the algorithm speed and energy consumption efficiency of particle swarm optimization algorithm applied to underwater glider path planning.