Design And Research Of The 2-DOF Parallel Vectored Thruster For AUV

As an effective platform for payload sensors, Autonomous Underwater Vehicle(AUV) has become a hotspot for ocean observation and ocean engineering nowadays. Higher requirements are also raised to mobility, maneuverability and operation accuracy of the seafloor mapping AUV. Although traditional control plane system can obtain good maneuverability for the underwater vehicle at relatively high speed, when the speed comes down, the steering efficiency will fell sharply. While vectored thruster has the ability of manipulating the direction of the thrust force of the propeller to obtain good maneuverability for the AUV. Especially at low speed, it can provide enough maneuverability for AUV to the underwater surveying.All in all, existing vectored thruster of AUV mostly adopt the structure of one motor to one DOF, in other words, serial mechanism. Compared to parallel mechanism, such a mechanism is born with problems such as small operating force, poor rigidity and difficulty to avoid using of large tanks, and so on. In order to avoid the problems mentioned above, this paper introduces parallel mechanism into the vectored thruster of AUV, which based on and improved from a 2-DOF spherical parallel mechanism(SPM). Then calculation and analysis related to the vectored thruster has been also completed. The specific research results are as follows.Firstly, in this article, configuration of the parallel vectored thruster mechanism was raised. In order to reduce the inertia and increase the rigidity of the parallel mechanism, the thrust motor was moved from moveable platform to fixed platform and a transmission limb was designed to transmit the rotation and torque from the thrust motor to the shaft system of propeller.Based on the preliminary design, the dimension of the vectored thruster was designed. And the configuration analysis was achieved to determine the length of the actuation limbs according to the position of the end of the SPM in the moving area. The kinematics analysis has been also accomplished.Then though the result of kinematics analysis and principle of virtual work, dynamics analysis about the SPM has been done, the torque of the actuation motor has been ensured by the position and kinematic parameter of the end of the SPM in the moving area. Then an extreme condition has been supposed to ascertain the max torque of the actuation motor according to the result of the dynamics analysis. Lastly, the selection of actuation motor has been completed.Lastly, the detail design of the SPS limb including the selection of universal joint and configuration of limb has been done. According to the detail design, this article also achieved finite element analysis to the SPS limb. And detail design and illustration related of the whole SPM has also accomplished.