Research On Design And Control Algorithm Of AUV Two Degree Of Freedom Vector Propulsion Mechanism

With the exploration of marine resources at home and abroad,and the complexity of the ocean environment.The functional requirements of exploration tools have gradually improved,and the flexibility of existing underwater vehicles in water is far from meeting the needs.For this reason,this paper aims at these disadvantages of some vector propulsion methods,such as actuator external and redundant degrees of freedom.A mechanism scheme based on a 2 degree-of-freedom vector propulsion mechanism is proposed,which is based on lower-mobility parallel mechanism and actuator can be arranged internally.This program uses the movable platform of the RS+2PRS parallel mechanism as the mounting base for the propeller.By changing the relative positions of components in two prismatic pairs,the 2 degree-of-freedom attitude adjustment of the AUV rear propeller can be achieved,and the AUV heading attitude can be quickly adjusted.The analysis of the structural characteristics and kinematics problems of vector propulsion mechanism.The whole structure of the propulsion mechanism adopts the form of RS+2PRS,which converts the rotating motion of the stepper motor through the gear and rack structure to the linear motion of the driving rod,and finally is converted to the adjustment of the posture of the moving platform.Because too many parameters of the whole mechanism and the coupling degree between parameters is high,the parameters of the parallel mechanism are decoupled,and the independent parameters of the mechanism are determined.Secondly,according to the decoupling results,a mathematical model is established for the coupling mechanism and the inverse solution is performed.The overall control algorithm is written by the inverse solution.The positive solution analysis of the parallel propulsion mechanism is carried out by numerical calculation,and the algorithm is improved according to the shortcomings of the traditional numerical method.Kinematic analysis of parallel mechanisms is mainly about speed and acceleration analysis of mechanisms.Finally,the correctness of the control algorithm and kinematics analysis of the mechanism is verified by MATLAB and ADAMS,which provides a theoretical basis for the development of the control system and the analysis of underwater dynamics.According to the motion characteristics of parallel mechanism,the control systemof parallel mechanism is developed by using modular programming idea.The basic functions of parallel vector propulsion mechanism are mechanism reset,speed setting,pose conversion and real-time display of drive displacement.Qt software is used to develop the motion control card for the two time,and the control interface is written.The motion control card is developed with Qt software for the two time,and develop the control interface.Mechanical analysis includes static analysis and underwater dynamic analysis.Statics analysis is through ANSYS to the main stress parts static stress analysis,to see the force distribution and design is reasonable.The structure of the AUV and tail vector propulsion mechanism is simplified,which simplifies the parts which have no influence on the result analysis,such as chamfering and thread holes.Then,it is introduced into the Fluent sub analysis software of ANSYS Workbench to carry out the underwater dynamic analysis through modifying the model,dividing the grid and determining the boundary.The simulated water speed is 1,1.5 and 2 sections respectively,and the simulation results can provide theoretical basis for structural optimization in the later stage.Finally,an experimental platform is built to control the motor through the control side,and verify the feasibility of the scheme.The correctness of the control algorithm is verified according to the displacement and dynamic position of the platform driven by the experimental platform.