Design And Implementation Of Compound Driven Underwater Robot

Marine ranch aquaculture has accelerated the green and efficient development of marine resources as a substitute for traditional aquiculture methods along with the increasing emphasis given to the sustainable development of marine resources.Since the marine environment is complex,changeable,and dangerous,the underwater robot to perform underwater operations is essential for the construction of marine ranches.Hence,this paper designed a hybrid-driven underwater robot to meet the needs of observing aquatic products in marine ranches.The robot is highly flexible and practical with the ability to propel through the water and crawl underwater.Specific research contents are presented as following:(1)An overall design scheme was proposed for the hybrid-driven underwater robot focused on the needs of monitoring operations in marine ranches.To be specific,floating,and crawling modules of the robot were designed respectively,including the carrier frame,crawling chassis,and the structural design of the traveling mechanism.Meanwhile,underwater motors and other components were selected together with the presentation of the propeller layout.Then,the robot design was completed by integrating these two modules as a whole,which provided a calculation model for solving the hydrodynamic coefficients.(2)A coordinate system was established to define the motion parameters of the robot and derive the coordinate transformation matrix.After that,the hydrodynamic coefficient to be obtained was analyzed through the establishment of the robot’s space motion equation and the hydrodynamic equation.Moreover,the principal theory and solution process of numerical simulation calculation were elaborated,providing a theoretical basis for the calculation of hydrodynamic coefficient using CFD.(3)The required hydrodynamic coefficient was solved via numerical simulation.First of all,the direct navigation and towing experiment was performed on the robot at varying speeds by means of numerical simulation to calculate corresponding resistance parameters.Next,horizontal and vertical oblique navigation experiments were numerically simulated under different drift angles(attack angles).And the hydrodynamic coefficients corresponding to oblique navigation were calculated through data fitting.At last,the force and torque variation laws were acquired from the numerical simulation experiment of the plane mechanism performed on the robot under five working conditions using the dynamic mesh technique and UDF compilation.And a six-degree-of-freedom space motion equation was established using calculated hydrodynamic coefficients.(4)Underwater crawling motion of the robot was modeled and simulated for performing physical experiments.The fluctuation range of the buoyancy center of the robot’s stable motion was first calculated under the conditions of underwater walking straight and underwater climbing in accordance with underwater crawling resistance following the principle of moment balance.It was then verified to be accurate through simulating motion stability under via the dynamic software.Furthermore,the analysis of the obstacle crossing simulation of the robot proved that the robot is equipped with the obstacle crossing obstacle within the range of the buoyancy center.Finally,land tests and underwater crawling experiments were carried out on the robot,respectively,proving that the robot is in conformity with the design requirements for it can walk straight,turn around,climb over slopes of 15 degrees and an obstacle of 50 mm underwater.