Research Of UUV’s Current Adaptibility In Shallow Sea Of Near-shore

The test of UUV mainly carried out in the marine environment,especially the offshoreshallow sea,the effect of ocean currents on UUV is particularly evident,therefore, this papermainly studies UUV’s adaptability of ocean currents in the offshore shallow sea. Two aspectsof path planning and motion control is discussed,int the aspect of UUV’s path planning in thecurrent environment, A*algorithm based on the path of optimal time is gived in this paper,In the horizontal plane, a variety of current models are established,then use the current modelsverified the effectiveness of the path planning algorithm of UUV. In the aspect of UUV’smotion control of the interference of current,this paper puts forward the iterative sliding modecontroller which has advantage of stability. According to the nonlinear characteristic ofUUV’s propeller and rudder,the speed controller and heading controller is designed.Then addthe different interference of current field to verify the accuracy of the controller.Based on a UUV of a certain version developed by Bestsea Research Institute, motioncontrol model is constructed, and further study aimed at the subject starts. This thesis dealswith some aspects as follows:First, the background and significance both at home and abroad concerning UUV isstudied.The features of the flow field of offshore sea and the difference compared to the theflow field of deep sea is analized. The researching circumstance concerning UUV withrespect to the flow field is presented from two aspects.Second, two coordinate systems are constructed to complete the subject, UUV spacialmotion functions are presented, the relationship between the absolute velocity and therelative velocity of the ccurrent is studied, the influnce of the flow field to the speed,drifting,and rudder is analized from the respect of mechanics.Third, the routing algorithm A*and the smoothening curve method B spline function ispresented, and the typical permanent field model and vortex model is constructed on the levelplane. The routing algorithm of UUV is tested through the vortex model.Fourth, through introducing variable structure control algorithm and specific analysis ofthe sliding mode control system, the iterative sliding mode controller is constructed, and thestability of the controller is analyzed. By adding interference of the flow field in thehorizontal plane, the effectiveness of the proposed method is validated by the simulation.Fifth, the software and hardware system of UUV simulation platform are described. Theeffectiveness of UUV path planning algorithm is analyzed, in which the steady flow, reverse flow and eddy flow are considered respectively. And also the effectiveness in steady flow andeddy flow of UUV movement controller is verified by simulation.Through the study of UUV path planning in the current field environment and UUVmotion control strategy in current field inference, the adaptability of UUV in offshore shallowsea current field is verified. By using A*searching algorithm in path planning and usingsliding mode controller in UUV movement control, the adaptability of UUV to offshoreshallow sea environment of current field is greatly improved.