Research On Hydrodynamic Performance Of Flexible Active Deformation Bionic Propulsion

With the deepening of the exploration of marine resources,the functionality of underwater robots has gradually become prominent.As an important part of underwater robots,propellers have always been an important factor restricting the development of underwater robots in multiple directions.At present,the main propulsion method used by underwater robots is still propeller propulsion,and its propulsion efficiency is generally40%-60%,and it has many shortcomings that affect its concealment.Fish swimming in the water has a higher fit with the water body,with lower water disturbance noise and better maneuverability.Bionic propulsion can be used as the main propulsion method of underwater robots.In this paper,a typical fish propelled by MPF mode is used as a bionic object,and its motion mode is extracted to establish a three-dimensional model of bionic wave fin.The analysis method of numerical calculation and experimental cross-validation is used to analyze the hydrodynamic characteristics of wave fin from the perspective of mechanics and flow field.Its influencing factors,and based on this research,designed and produced a set of underwater bionic propeller principle prototypes to verify the feasibility and correctness of the research content.This paper first introduces the theoretical methods of hydrodynamic performance analysis of wave fin bionic propulsion,including basic equations,numerical algorithms,dynamic mesh methods,UDF methods and so on.In addition,approximate processing methods are used to reasonably approximate the shape and motion state of the model,simplify the model,and improve calculation efficiency.Secondly,analyze the law of wave propulsion of the bionic object,establish the motion equation of the bionic wave fin and the three-dimensional surface model.Using the elastic smoothing model and local mesh reconstruction technology,the RANS calculation method of the hydrodynamic performance of the zero-thickness bionic wave fin is established,and the reasons for the thrust of the bionic wave fin are explained from the pressure factors and flow field factors.The influence of wave parameters such as wavelength,amplitude and frequency of motion parameters,as well as external parameters such as incoming flow velocity and diving depth,on its hydrodynamic performance are studied,so that the calculation results are closer to the actual working environment of the bionic wave fin.Then,design the bionic wave fin test mechanism,the mechanical structure adopts the transmission mode of "steering gear-swing rod-bionic wave fin",and the control adopts the data transmission mode of "computer-decoder-steering gear",which better solves the mechanical structure and movement.Control problems.The test content corresponds to the numerical calculation content,and the results are highly consistent.Finally,based on numerical values and experimental results,a set of prototypes of underwater wave fin bionic propellers were designed and produced,including the main design contents such as shape design,mechanical structure design,and control mechanism design.In order to verify the feasibility and reliability of the prototype design,a series of pool motion tests were carried out.The results showed that the prototype can smoothly complete straight,in-situ turns,and angled turns,which meets the design expectations.