Research On Coordinate Control And Uncertainty Analysis For Underwater Glider Formation

Ocean research and resource exploitation is the significant national development strategy of China.Underwater glider,as a new type of autonomous underwater vehicle,has become the most competitive platform for long-term,large scale observing task for its advantages of low cost,long endurance and easy recycling.Fleet of underwater gliders can further expand the abilities of the individual and develop its abilities in high spatio-temporal resolution observation,which will play an irreplaceable role in multidimensional surveillance network for the ocean environment.This work focus on the coordinated control of multiple underwater gliders and the uncertainty problem during the fleet task.Artificial potential fields(APFs)and the theory of multibody system are adopted in the coordinated motion control and attitude coordination of the fleet.The uncertainty factors in the task process are discussed and the influence of the uncertainty factors both on the motion trajectories and the task qualities are analyzed.Meanwhile,the delopyment design the glider task is discussed based on the uncertainty analysis.The main contributions of this thesis are summarized as follows:1.A task control architecture and a multi-layer coordinated control strategy are designed based on the theories of multibody system and system architecture for intelligent groups.A multi-layer coordinated control system is designed for the practice considerations of glider operating characteristics in autonomous perception and control,the near real-time communication condition and lateral motion coupling.Based on the multibody system theory,the APF method is adopted in the 2D path planning for the fleet.The trajectory following and diving depth control are also fulfiled.Attitude coordinate of the fleet is studied based on the Huston analysis method and the attitude potential field is established between gliders to generate control torque.The simulation and experiments of three coordinated Petrel-II gliders verifiied the practical ability of the control strategy.2.The LEC optimal control strategy is researched to minimize the energy consumption of the glider operation and further extend the voyage ability of the glider.The energy consumption model is established by analysis the gliding motion pattern and the hybrid propulsion pattern.Meanwhile,the ocean flow is estimated and the control heading angle of glider is designed.A simulation test is executed to analyze the energy regularities of the energy consumption with different control variables.And the LEC strategy was also implement in the sea experiment.3.A uncertainty analysis method for the fleet of underwater glider is researched.The influence of uncertainty flow and uncertainty sensor errors are discussed based on the monte carlo sampling method(MCS).And the sensitivity of multiple uncertainty factors is researched based on the extended Fourier amplitude sensitivity test method(EFAST).Moreover,a primary method in fleet design is presented based on the uncertainty analysis.