| With the development of society and science and technology,The application of underwater vehicles has become more and more extensive,and they can be seen from the small drainage pipe to the limitless ocean.In recent years,the demand of mini underwater vehicles for underwater detection and information collection is increasing in the field of shallow water research and development.With the advantages of small volume,small resistance,flexibility,low cost,convenient carrying,mini underwater vehicles are very suitable to become a kind of unmanned and intelligent underwater equipment.They are often used for River embankment dam water condition monitoring,river pier underwater information collection,offshore port and port maintenance,and underwater detection of ship's outer body and so on,saving a lot of manpower and material resources.Therefore their market prospect is very good.The research of mini underwater vehicles is becoming more and more popular with researchers.When a mini underwater vehicle works underwater,its volume and quality factors make it more susceptible to the effects of wave current.It is especially important to improve the accuracy and stability of the mini underwater vehicle when it is in motion.This paper discusses the research progress and dynamics of underwater robots both at home and abroad.It introduces the position detection technology of underwater vehicles,compares and summarizes the advantages and disadvantages of several common motion control methods,and proposes an adaptive fuzzy PID control algorithm which combines the advantages of fuzzy control and PID control and is able to achieve a more stable and effective motion control.This paper uses a frame-type six degree of freedom mini underwater vehicle as the research object,which is mainly used for shallow water area information collection,pier and wharf underwater detection,underwater repair of the ship's outer body,etc.Itis possible to achieve a spatial motion of six degrees of freedom with six propellers symmetrically distributed.The coordinate system of the mini underwater vehicle is established according to its the structural characteristics and movement.The kinematic equation of the six degree of freedom of the mini underwater vehicle is derived According to its underwater motion law and reference data.By analyzing the force during underwater movement,the dynamic equation of the mini underwater vehicle is finally established,which is the spatial motion model of the mini underwater vehicle.Under certain conditions,the motion control model for the depth-determining motion and the heading motion of the small underwater robot was deduced,which lays a foundation for the study of its motion control.The position and attitude detection of underwater vehicles is also the basis for realizing the control motion.Introduce the contents and methods and the hardware system of underwater vehicles position and attitude detection.And the particle swarm optimization(PSO)algorithm is applied to the mini underwater vehicle positioning system.The positioning speed is improved by deducing the position of the mini underwater vehicle during the gap of the positioning sonar measured signal.The fuzzy control technology and PID control technology are introduced and studied in detail.The design steps of fuzzy controller and PID controller are given.Based on this,an adaptive fuzzy PID controller that combines fuzzy control and PID control is designed..The transfer function of depth-fixing motion control system and radial-direction motion control system was deduced.In the computer simulation software MATLAB,the simulation model of the three-controller depth-measuring motion control system was built using Simulink module,and computer simulation was performed..The simulation test verifies the feasibility and effectiveness of the designed adaptive fuzzy PID control.Compared with the simulation results of using the fuzzy controller and the PID controller alone,it shows that the adaptive fuzzy PID controller has better response speed and stability.Sexual and dynamic performance further validates the feasibility and effectiveness of adaptive fuzzy PID control. |
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