Design And Research Of The Underwater Robot Vectored Thruster With Parallel Mechanism

Due to human dependence on Marine is increasing year by year, all kinds ofMarine survey equipment are emerging endlessly. As an effective platform for pickingup the sensors, AUV (autonomous underwater vehicle) has become the main directionof marine survey equipment. The underwater work environment that the AUV faces isvery complex, so good maneuverability and reliability are important to expand thescope of AUV mission and improve the ability of underwater survival. Based onexisting propulsion technology of aerospace, aviation, and underwater robot, thisarticle designed a vector propeller based on parallel mechanism in order to meet theneeds of underwater robots advance and manipulation. The research contents of thepaper are as follows:(1) This paper proposed a vector propeller based on parallel mechanism, namely3-RPS and SPS combined mechanism. Among them, the3-RPS mechanism canchange the axis of the propeller by changing the space of the moving platform,realizing the adjustment of propulsion direction. The moving platform which is drivenby three parallel actuating cylinders has a simple and compact structure and the largeworking space. In addition, three actuating cylinders are involved in manipulation atthe same time, the vector propeller has high dynamic stiffness, and the motor load issmall. The SPS mechanism can convey torque and rotational speed of main motor tothe propeller which motions following the moving platform, so the main motor don’tmove following the moving platform, it reduces moving inertia of the movingplatform and the motor load, and makes structure layout optimization on the basis ofguarantee the reliability.(2) According to the specific AUV geometry size, sports space and other designrequirements, I have analyzed kinematics and carried on the dimension synthesis ofthe parallel mechanism on the propeller by using Newton euler method, the size of themain components are obtained. With the analysis object of propeller pitching andswerving movement, based on the acceleration, speed curve of the propeller swing, Ihave calculated the change process of three RPS branched chain length speed andswing Angle with time, the maximum acceleration of the RPS branched chain isobtained in the movement process.(3) The key components of vector propeller have been designed and checked, such as propeller shaft, the spline on the SPS branched chain, connecting rods of ballhinges on the actuating cylinders and lead screw nut pair.(4) The article has calculated pressure compensator working volume andconfirmed the design of its connection structure. In view of structure characteristicsand movement way of the vector propeller, the article presented the scheme ofpressure compensator design and layout.