Research On Observed ROV Motion Control Method

In the 21st century,all countries in the world have accelerated the pace of exploring and developing marine resources.China,as a world power,is also a large marine country.It has rich marine resources to be explored and developed urgently.Observation-based ROVs play a role in the process of exploring and developing marine resources.Increasingly important role Observation-type ROV,as an underwater working tool,has been widely used in water because of its small size,wide range of motion,sufficient energy,strong operability,and long-term operation in complex underwater environments.Various fields related to operations:for example,in the field of scientific research,used to inspect water bodies,geology,and underwater animal and plant research;in the field of public safety,search and rescue of underwater objects Wrecked personnel;in the field of engineering construction,inspecting,repairing and maintaining underwater facilities,dams,offshore support structures;in the deep-sea fisheries aquaculture field,regularly inspecting breeding cages.Therefore,it is necessary to conduct in-depth research on the key technologies of ROV.Based on the mission requirements of underwater environment observation operations in shallow waters,this paper designs an observation ROV with a depth of 300 meters.Then,with the observation ROV as the research object,the preliminary overall design of the ROV,the dynamic positioning control method,the trajectory tracking control method,and the thrust control allocation method were thoroughly studied.The specific research content is divided into the following points:First of all,the overall preliminary design of the observing ROV from the observation system,propulsion system,sensing system and control system is made;the force of the ROV during the underwater movement is analyzed,and according to Fossen and others The modeling method performs mathematical modeling of the kinematics and dynamics of the ROV,and at the same time establishes the external environment interference force model.Then,based on ROV,there are inaccurate modeling problems,and the positioning accuracy is inaccurate due to interference from ocean currents and tides during ROV underwater positioning.The sliding mode interference controller is designed to compensate for external interference and model uncertainty.Positioning error,and then set up the controller model and ROV dynamic model in the simulation environment,so as to design and complete the dynamic positioning control system.The effectiveness of the sliding mode disturbance observer is verified by simulation experiments.Then,according to the characteristics of ROV underwater trajectory tracking,the conventional ROV underwater model is deformed first,so that each item in the model becomes a function term of position and time.Based on the deformed model,an adaptive fuzzy sliding mode controller is designed.Two different tracking trajectories are designed during the simulation experiment,and then the tracking effect is compared with the sliding mode controller and fuzzy sliding mode controller.The experimental results verify the superiority of the adaptive fuzzy sliding mode controller.Finally,the mathematical model of the ROV horizontal thrust distribution system was completed based on the layout characteristics of the ROV thrusters.The optimization objective function and constraints of thrust control allocation were established,and a thrust control allocation method based on PSO optimization algorithm was designed.Real-time forces and moments of 3 degrees of freedom in the horizontal plane calculated by the motion controller during the trajectory tracking process are optimized as the forces and moments expected by the ROV.Through simulation experiments,the designed thrust control allocation method and the pseudo-inverse allocation method are compared to the allocation effect.Finally,the effectiveness and superiority of the PSO optimized thrust allocation algorithm are verified.