Design And Dynamic Characteristics Of Long Range AUV Buoyancy Control System

Chinese Marine science and technology are constantly developing.AUV,as an underwater vehicle capable of carrying a variety of survey facilities and sensors at the same time,can realize a large range of autonomous detection in the ocean according to the established mission planning by relying on its own energy,which is more and more widely used in the field of Marine research.At present,the low-power buoyancy regulating system has become a research focus of long-range AUV.In addition,in order to avoid the navigation resistance caused by an unbalanced force,AUV needs to realize the balance of buoyancy and gravity,and an accurate buoyancy regulation system plays an important role.This paper proposes a buoyancy regulating system which is carried on a long-range AUV.On the premise of ensuring small space and reliable performance,the buoyancy regulating system with large displacement can be realized.The AUV can complete the upward and downward movements and be precisely adjusted underwater to ensure the balance of buoyancy and gravity of the AUV at different depths.On this basis,the dynamic performance of the buoyancy regulating system is simulated and optimized.The main research contents are as follows:(1)According to the overall design requirements of the buoyancy adjustment system,compared with the mature buoyancy adjustment scheme of the underwater vehicle at this stage,the buoyancy adjustment hydraulic system scheme of multi-stage pump oil discharge and dual-channel oil return is determined,which can achieve large displacement buoyancy.Adjust and accurately adjust the amount of oil underwater.Based on the scheme,the principle diagram of the buoyancy adjustment system was designed,the specifications of the components were determined through calculation,and the performance of the hydraulic system was calculated and checked.(2)The mathematical model of dynamic characteristics of hydraulic oil,hydraulic pipeline,hydraulic fixed pump,direct-acting relief valve,accumulator and outer capsule in the buoyancy regulating system of the long-range AUV is established.The computer simulation technology based on MATLAB/Simulink module was used to draw the simulation models of the components as mentioned above,and the component simulation experiments and pressure characteristic experiments were completed.The experimental results verified the rationality of the built model and the accuracy of power calculation.(3)The node cavity method is adopted to build the Simulink closed-loop model of the entire long-range AUV buoyancy regulation system with the simulation model of each component.The instantaneous flow rate and pressure characteristic response of the outer skin is used as the evaluation index to simulate and analyze the dynamic characteristics of the model,and the influence law of parameter changes on the system instantaneous flow response is studied:Is negatively correlated with the load pressure and positively correlated with the accumulator precharging pressure.(4)Genetic algorithm is used to optimize the parameters of the buoyancy regulating system of the long-range AUV.The optimal accumulator precharging pressure is 2.09 MPa when the expected steady flow rate is 3.85 m~3/s,and the dynamic response of the buoyancy regulating system is obtained.