Study On The High-performance Adsorption Mechanism Of Leech Sucker And The Design Of Bionic Sucker

With the continuous improvement of industrial production and automation level,vacuum equipment has been widely used.The development of high-performance vacuum suckers has become increasingly important in industrial manufacturing.Therefore,it is of great significance to develop a new type of suction cup with high reliability and strong adsorption performance.Many organisms have evolved suction cups structure with superior performance in adapting to the natural environment.These biological suction cups have not only strong adsorption power but also have strong surface adaptability.It is of great significance to develop a bionic sucker with high adsorption performance based on the adsorption mechanism of these biological suckers.As a typical multi-sucker creature,leeches like to adsorb on various rough surfaces such as the grass or the bottom of rocks on the river bank.The leech can also use its front and back suction cups to crawl in an inchworm style.In this paper,guided by the engineering bionic theory,the structure of the sucker of leeches and its adsorption capacity were studied.In this paper,based on the surface structure and morphological characteristics of the sucker of leeches,a bionic design of the existing sucker is carried out to obtain a bionic vacuum sucker with high adsorption performance.The high-performance adsorption mechanism of leeches' suckers was studied.Used the stereomicroscope and SEM to observe the surface morphology and cross-sectional structure of the biological sucker.Observations found many wrinkles and pits with a diameter of 0.5-1.5 ?m on the sucker surface.The morphological changes during the autonomous adsorption,autonomous desorption process and the pull-off process of the posterior sucker were compared and analyzed.An electronic tensile testing machine was used to test the leeches' posterior sucker adsorption forces on different vacuum conditions and different roughness surfaces.The tests found that negative vacuum pressure played an important role in the adsorption of leeches.Besides,the tests also found that leeches have good adsorption properties on rough surfaces.The adsorption mechanism of leeches on rough surfaces is analyzed.The analysis found that the high-performance adsorption and sealing of leeches on the rough surface is formed by the combined action of vacuum negative pressure adsorption,micron-scale pit structure adsorption,mucus sealing,and tissue deformation sealing.Based on the high-performance adsorption mechanism of the leech sucker,the morphological elements of the leech sucker surface are analyzed and extracted.A partial orthogonal polynomial regression design method was used to formulate a test plan for the adsorption force of the bionic sucker.The bionic suction cup and its mold were modeled and processed according to the test mentioned above plan.Nine groups of bionic suction cups and 1set of standard suction cups for comparison test were obtained.The adsorption performance of the standard suction cup and the bionic suction cups were tested.The test results showed that the adsorption force of the bionic sucker is significantly greater than that of the standard sucker.The adsorption force of the optimal combination of factors is improved by nearly 50% compared to the standard sucker.Based on the adsorption force test results,the range analysis and regression equation fitting were carried out.The response surface graph of each factor level to the suction cup adsorption force was drawn using the fitting equation.The response surface showed that the adsorption force of the bionic sucker would increase with the increase of the pit diameter and row spacing of the hemispherical pit structure.The increase of the single row of hemispherical pits showed a trend of increasing and then decreasing.In order to study the mechanism of the performance improvement of the bionic sucker,the force status of the standard sucker and the bionic sucker in the adsorption state was analyzed through the FEM and the ANSYS Workbench simulation platform.Besides,the pull-off process of the standard and bionic suction cups was observed.The research results showed that: The bionic sucker increases the contact area between the working surface of the sucker and the surface of the substrate and uses hemispherical pits to deform to form a secondary sucker,allowing the sucker to obtain a greater adsorption force;increases the contact pressure between the suction cup and the surface of the substrate to improve the sealing performance;increases the frictional stress between the suction cup and the surface of the substrate,the hemispherical pits desorb row by row,to reduces the damage to the enclosed space of the suction cup by the tensile force.