Tensegrity-based Biologically-inspired Wing Design With Application In Underwater Gliders

As a new type of unmanned underwater autonomous vehicle,underwater glider has been widely used in the field of marine environmental observation for its advantages of low power consumption and long duration mission.However,the traditional underwater glider relies on buoyancy propulsion and glides with fixed rigid flat wing,which is unable to resist the current disturbance and has weak maneuverability.The hybrid-propulsion underwater glider has problems of high noise and weak concealment due to the introduction of propeller.In this paper,we develop a tensegrity wing to achieve large-amplitude deformation and propulsive force as the propeller of the glider.Tensegrity is a structure composed of bars and cables.The main research work and results of this paper are as follows:Firstly,the internal structure and movement characteristics of manta ray’s pectoral fins are analyzed to meet the requirements of large deformation and large thrust bionic wings for underwater gliders.Based on the biological parameters of manta ray’s pectoral fins,a Tensegrity-based bionic fin is designed.The dynamic modeling was carried out,and the motion law of the bionic fin and the tension change law of the elastic rope were analyzed from the static equilibrium condition and the external excitation respectively,which verified the feasibility of the Tensegrity structure as the foundation of the bionic fin structure.In addition,the relationship between the modal frequency of the bionic fin and the stiffness of the elastic rope is established,and the reasonable choice of the stiffness of the elastic rope makes the modal frequency of the bionic fin consistent with the hydrodynamic resonance frequency,so as to achieve resonance energy saving.Secondly,the double-layer Tensegrity structure is used as the basic skeleton of the bionic fin,and Multiple Cable-routed actuation(MC)wiring is used to drive the bionic fin,so that each structural unit can achieve large deformation.Based on the structural parameters determined in the preliminary analysis,the mechanical structure design of Tensegrity bionic fin joint,cam and other key components is completed.At the same time,the motion control scheme of the bionic fin was designed,and the selection of key components such as the actuation cam was completed.With the overall design goal of light weight,simple control and deformation,the 3D model design of the bionic fin was completed.Finally,each fin was driven by an actuation cam in the air to complete the swing test.In order to solve the problems of the structure in the experiment,such as the slight oscillation,small swing amplitude and asymmetry of left-right swing,the bionic fin was designed to reduce the weight and the wiring method was improved,so that each fin could achieve the large deformation.On this basis,the platform of bionic wing propulsion experiment was designed and built,and the swing performance of the bionic wing in the air was analyzed.The experimental results show that the bionic wing has good performance of large-amplitude deformation.