Study On The Adsorption Of Abalone Abdominal Foot And The Design And Experiment Of Bionic Sucker

As an important terminal actuator component in the automation industry,vacuum sucker is not only widely used in the industrial field,but also in people's daily life.Due to the huge demand of vacuum sucker,wide range of applications and great differences in use environment,it is of great practical significance to further improve the adsorption performance of vacuum sucker and meet the actual needs of different industries.In order to survive and develop better,organisms in nature have fully adapted to their own living environment through continuous evolution for a long time.As one of the basic abilities of many animals,adsorption capacity is the key to ensure their survival.Abalone as a common aquatic organism,its gastropod has a strong adsorption capacity,which can be firmly adsorbed on the reef surface in water.Based on the idea of engineering bionics,the abalone gastropod is used as the bionic prototype.Firstly,the morphology and adsorption ability of abalone gastropod are studied,and then the bionic sucker is designed according to the surface morphology of abalone gastropod,so as to improve the adsorption and sealing of vacuum sucker.In this paper,the macroscopic and microscopic morphology of abalone abdominal foot surface was observed by microscope,and it was found that the abdominal foot surface was composed of a large number of fibers perpendicular to the surface.In order to analyze the composition and proportion of various forces in the adsorption force of abalone abdominal foot,the basic adsorption principles and corresponding calculation methods of several common adsorption forces in aquatic adsorptive organisms,such as vacuum negative pressure,van der Waals force and capillary force,were studied.Five kinds of force measuring plates were designed and processed for abalone adsorption tensile test,and the hooks used to pull up abalone were designed and manufactured by 3D printing method.The abalone with mass range from 50 g to 60 g was selected for tensile test,and each force plate was tested for 10 times.According to the test results,the composition of the adsorption force of abalone abdominal foot and the proportion of each force were analyzed and calculated.According to the analysis results,the adsorption force of abalone abdominal foot is mainly composed of vacuum adsorption force and van der Waals force,in which vacuum negative pressure accounts for the largest proportion,which is about 60% of the total adsorption force.Van der Waals force generally accounts for about 20% of the total adsorption.The liquid bridge force accounts for only about 1% of the total adsorption force.The main function of the liquid bridge force is to fill the gap between the abalone abdominal foot and the adsorption surface,improve the sealing between the abdominal foot and the force measuring plate,thus indirectly improve the adsorption performance of the abdominal foot.In the adsorption force of abalone abdominal foot,the adsorption caused by vacuum negative pressure is mainly divided into three parts,namely,the adsorption of abalone abdominal foot as a whole as a sucker,the local vacuum adsorption of abalone abdominal foot and the equivalent adsorption caused by friction between abdominal foot and force plate to prevent sucker shrinkage and deformation and leakage.These three effects account for about one-third of the vacuum negative pressure adsorption force respectively.Six kinds of glass plates with different surface shapes were selected as force measuring plates to test the adsorption capacity of abalone.According to the experimental results,the adsorption force of abalone's gastropod on the glass plate with different surface roughness is not significantly different,and the adsorption force of abalone's gastropod on the glass plate with different surface morphology is significantly different.When the surface morphological characteristics of glass plate and the morphology between adjacent shapes change too quickly,that is,the corner is sharp,it is difficult for the abalone abdominal foot to form a good adhesion state with the adsorption surface completely,so the improvement of adsorption is not obvious.When the surface morphology of the glass plate changes slowly and the rotation angle is too slow,the abalone abdominal foot can form a good adhesion state with it,thus increasing the adsorption area of abalone abdominal foot on its surface and increasing the adsorption force of abalone abdominal foot.When the abalone abdominal foot is adsorbed on the surface of the glass plate with the shape of pits,the abdominal foot and each pit form an independent sucker structure,so that the adsorption capacity of the abdominal foot is significantly improved.The actual vacuum sucker in industry is selected as the prototype,the three-dimensional model of the standard sucker is established,and the force on the bottom surface of the standard sucker is analyzed by finite element analysis software.The morphological characteristics of the abalone abdominal foot during adsorption were extracted,and the bionic shape was designed on the bottom of the standard sucker.A total of 16 kinds of bionic suckers were designed and analyzed by finite element method.From the analysis results,it can be seen that the width of the sealing ring and the distance between the striped groove structure and the center of the sucker have great influence on the adsorption of the bionic sucker,while the distribution angle and number of grooves have little influence on the adsorption of the sucker.The bionic sucker with the width of sealing ring is 1.5mm and the distance between striped groove and the center of sucker is 20 mm has better adsorption performance,and the bionic no.8 sucker has the best adsorption performance.According to the 3D model of standard and bionic suckers,the mold for pouring suckers is designed,the mold is processed and manufactured by 3D printing,and the standard and bionic sucker entities are obtained by pouring.The vacuum suction cup adsorption and sealing test bench was designed and built,and the adsorption tensile and sealing test were carried out for standard sucker and bionic sucker entity.The experimental results show that the bionic no.8 sucker has good adsorption performance,and its maximum adsorption force is 5.32% higher than that of the standard sucker at 40% vacuum.In the sucker tightness test,the leakage of bionic no.8 sucker is the smallest,which is 53.2% less than that of the standard sucker.The results show that the bionic no.8 sucker has good adsorption and sealing performance,which is consistent with the finite element simulation results.A high-speed camera was used to film the whole process of the sucker from adsorption to being pulled up.From the analysis,it can be seen that the key to improving the adsorption performance of the sucker is to prevent the force on the edge of the sucker from contracting and sliding inward and to connect the inner cavity of the sucker with the outside atmosphere.The ring sealing ring structure of the bionic sucker edge can effectively improve the sealing performance of the sucker edge,and the striped groove structure of the sucker can provide more space for the inward contraction of the sucker edge when the edge is extruded and raised.Slow down the degree of relative extrusion at the edge of the sucker,reduce the probability that the interior of the sucker is connected with the outside due to the uplift of the edge of the sucker,thus improving the adsorption capacity of the bionic sucker.