Stability Optimization Design Of Small Underwater Robot Based On Singular Perturbation Method

At present,with the rapid construction of "marine pastures" and the in-depth exploration of marine resources,Unmanned Underwater Vehicles(UUV)are being widely used in the exploitation of marine minerals,fisheries and other resources.Aiming at the problems of difficulty in operation,susceptibility to interference,and easy damage in the process of UUV miniaturization and popularization,this paper,based on the self-designed "Aquaman V3" small underwater robot,improves the performance of small underwater robots by optimizing hardware and control algorithms.Stability capabilities enables it to resist external disturbances such as ocean currents and collision,improve control accuracy,and reduce accident rates.In terms of hardware,an open-frame structure is selected and the computational fluid dynamics(CFD)simulation is used to verify the impact resistance of the structure.While adopting the dual-chip structure,the unique design of the cabin dryer ensures the stability of the circuit.Temperature,humidity,depth and MPU9250 attitude sensors are selected to measure the information required for robot control from multiple angles.Propellers,external cameras,manipulators and other components are selected and designed to enrich the functions of small UUV.Batteries and remote cables are used for power supply to ensure energy supply.In the aspect of algorithm control,the mathematical model of the small UUV is obtained and simplified by using the momentum theorem and the dynamic moment theorem in conjunction with the two-coordinate system.The time scale decomposition method is used to reduce the coupling degree of the simplified model,and the singular perturbation model of the small UUV is obtained.CFD simulation method and complementary filtering algorithm are respectively used to determine the hydrodynamic parameters and position and attitude information so as to make the model more accurate.A series-parallel PID control method is designed based on the singular perturbation model,and a class of nonlinear methods are used to adjust the PID parameters to improve the stability ability of UUV,improve the control accuracy,and reduce the control error.Finally,the prototype of a small UUV is assembled,and the hardware performance is tested by a pressure simulation device.Matlab / Simulink is used to simulate the series parallel PID control and compare with the classical PID control to verify the high stability of the series parallel PID control against external disturbance.The tank towing experiment,anti-disturbance test and grab test are designed to check whether the hydrodynamic parameters are accurate,and verify whether the stability performance and control accuracy of the small UUV meet the design objectives.