Research On Design And Kinematic Performances Of Parallel Pitch Control Mechanism Of Controllable Pitch Propeller For Underwater Vehicle

With the development of marine economy,more and more attention has been paid to the exploration and exploit of marine resources in China and abroad.As a kind of unconventional propeller,controllable pitch propeller can produce multidimensional propelling force,which provides a good choice for the flexible operation of underwater vehicle.As the underwater vehicle can only be manipulated remotely,the pitch control mechanism turn into the key mechanism that affects the application of the controllable pitch propeller in the underwater vehicle.The flexibility of underwater vehicle is determined by the kinematic performance of pitch control mechanism.Therefore,the pitch control mechanism was taken as the research object in this paper,and the following research works has been carried out:Design of the pitch control mechanism and underwater vehicle:According to the degree-of-freedom analysis of pitch control motion,the PS-RRS-2RUS parallel mechanism was chosen as the supporting mechanism for pitch control.The degree-of-freedom of the selected mechanism was verified.The layout of controllable pitch propellers and the motion controlling method of underwater vehicle was scheduled.Kinematic and dynamic modeling of the PS-RRS-2RUS parallel mechanism:The position and velocity models of the pitch control parallel mechanism were established.The velocity Jacobian matrix was derived.Based on the kinematic model,the velocity mapping analysis,the acceleration mapping analysis and the force analysis was carried out.The dynamic model of the parallel mechanism was derived by the principle of virtual work.Kinematic performance of the PS-RRS-2RUS parallel mechanism:The singular problem of the PS-RRS-2RUS parallel mechanism was studied by the method of Jacobian matrix analysis.The workspace of the parallel mechanism was obtained.The dexterity and static stiffness of the mechanism in the workspace was studied.Virtual prototype modeling and control simulation of the PS-RRS-2RUS parallel mechanism:The virtual prototype model of the pitch control mechanism was established with SolidWorks and SimMechanics.The kinematic and dynamic models of the mechanism were verified after simulation.A PID controller based on the hinges space was designed for the control simulation of the parallel mechanism.