Design And Research Of Parallel Vector Propulsion System With Less Degree Of Freedom

With the increasing demand for exploration of marine resources,people's requirements for the maneuverability of underwater vehicle in complex marine environments are becoming higher and higher.How to effectively improve their maneuverability has become a hot issue in research.The vector propulsion technology can not only effectively improve the maneuvering performance of underwater vehicle,but also complete the propulsion tasks of multiple propellers through the vector propulsion,which is also important for improving its endurance.In this paper,a less-freedom parallel vector propeller is designed based on the parallel mechanism,which can improve the maneuverability of underwater vehicle in complex ocean shallow waters.Simulations are made for its kinematics,dynamics,and rigid-flexible hybrid system dynamics research work.The specific work and conclusions are as follows:This article first analyzes the motion requirements of the underwater vehicle and proposes the design requirements of the vector propulsion.The vector propulsion mechanism is designed.The degree of freedom is analyzed using the spiral theory,and the three-dimensional parallel vector propulsion with fewer degrees of freedom is established.Based on the theoretical analysis of the inverse solution of the branch chain,the relationship between the length of the rod and the rotation angle is obtained.The pitch and yaw poses of Matlab are used to obtain the curve of the branch chain travel and joint rotation angle.Establish a relevant Jacobian matrix to pave the way for dynamic analysis.Based on Adams,the degree of freedom of the vector thruster was verified,and the motion simulation under full rotation and expected pitch of ± 30 ° and yaw ± 30 ° was carried out to obtain the relevant kinematics characteristic curve,and also verified the rod length and The correctness of the theoretical analysis of the inverse solution of the rotation angle.The forward kinematics analysis of the data obtained by Adams inverse solution simulation was performed using Matlab.The angle change curve of the dynamic platform is obtained,which verifies the correctness of the inverse solution simulation,and the workspace was solved.The simulation data is obtained for the follow-up The motion control of the prototype provides the necessary data support.Then,using the principle of virtual work,the dynamic equation of the vector thruster is established,and the working load of the vector thruster is analyzed,which provides accurate load information for dynamic simulation.Adams was used to perform dynamic simulations in pitch and yaw poses.The changes of the force,torque and driving power consumption at the branch chains and joints were obtained.The main factors limiting the dynamic characteristics were analyzed.Finally,the branched rods were flexibly processed to establish a rigid-flexible hybrid system model,and the modal and frequency changes of the branched rods were obtained.Adams was used to simulate the dynamic characteristics of the rigid-flexible hybrid system,and the results were compared with the rigid body system.It is found that due to the existence of flexible bodies,there are certain differences in the dynamic characteristics of rods,and the state of flexible bodies is closer to the true dynamic change law.The analysis results are more suitable for the research of underwater vehicle vector thruster.A prototype of a vector propulsion mechanism was built,and a control experiment was carried out based on kinematics simulation data.The actual motion of the moving platform was consistent with the expected motion.The dynamics control and simulation results in this paper show that this small-degree-of-freedom parallel vector thruster can satisfy full-rotation vector propulsion and has good kinematics and dynamics performance.It can improve the maneuverability of underwater vehicle under complex load conditions in shallow ocean waters.