Research On Navigation And Control Algorithms For Water Gliders

Hybrid Underwater Glider(HUG)is a novel autonomous ocean.environment monitoring platform with the capability to convert internal actuators,external propulsion and a vertical rudder unit to get forces and moments required for the desired glider path.Besides,high accuracy motion control is one of the most essential features required to ensure reliable and robust underwater operations of HUGs.However,the cluttered and uncertain ocean environments HUGs worked make a great challenge for navigation control of HUGs.To deal with uncertain external disturbance and model nonlinearities,a new closed loop navigation control strategy was presented,which integrated a glider control inputs filtering algorithm,a new hybrid heading tracking control algorithm and a new path following control algorithm.Simulation studies and corresponding experimental verification were performed.The main contents of this thesis are as follows:Firstly,the dynamic model of an underwater glider named as Petrel-? 200 was modeled to serve as a controlled plant.The navigation control inputs such as glider heading angle,position information were filtered by a particle filter.And the effectiveness of the proposed filtering algorithm was validated by simulations.Secondly,to deal with non-linear flow disturbance and saturation in actuator,a new hybrid heading tracking control algorithm was presented,which integrated an adaptive fuzzy incremental PID(AFIPlD)and an anti-windup(AW)compensator.The control parameters could be adjusted on-line based on the filtered glider heading,and the AW compensator dynamically adjusted the rudder angle,which would improve the adaptability and robustness of underwater glider's heading control.Then,a new path following navigation control algorithm based on the underwater glider was put forward for high accurate path following.control considering external disturbance.This algorithm integrated a Light-of-Sight(LOS)algorithm as global path following control,a B-spine approximation algorithm as a path switching control and an adaptive natural network control algorithm as a depth adjustment.And combined the path following control algorithm with the heading tracking control mentioned previously,a new closed navigation control strategy was presented,which could achieve a high accuracy navigation performance.Finally,the validities of the proposed closed navigation control strategy were verified by simulations and experiments.The results showed that the proposed control strategy could effectively improve the navigation accuracy and the robustness of the underwater glider.