Bionic Research In Mars Rover Wheel Based On Plantar Morphological Characters Of Ostrich Foot

Based on the superior performance of plantar surface morphology of ostrich foottraveling in sand environment, Focused on ostrich plantar surface morphology, this paperstudied the surface/sand interaction law as well as the coordinated strategy between two toesof ostrich foot during touching ground process. Combined with Bionic principle, theengineering bionic technology was employed to design a kind of Mars Patroller bionic wheelstructure which has high passing ability on soft grounds. Meanwhile further analysis andevaluation were carried out on the through performance of this Bionic wheel.Using three-dimensional laser scanner to obtain ostrich plantar surface and construct athree-dimensional data point cloud geometry.Geomagic Studio reverse engineering softwarewas employed for geometry processing. The ostrich plantar surface was divided into fourtypical feature areas, namely the forefoot gradual surface, the middle groove and the heelspherical cap of the third toe plantar surface, and the Ⅳ toe plantar surface. In combinationwith the discrete element EDEM software and finite element software Patran/Nastran, thenumerical simulation of ostrich plantar surface and analysis on the deformation of theplantar surface under static compression were conducted to explore the sand fixation andlimitation mechanism of ostrich foot surface. The analysis results show that the sand mobilityalong the longitudinal direction is lower than the transverse direction. The plantar surfacemorphology played a positive role in reducing the slip degree when ostrich feet travel on sand.On the plantar surface of ostrich foot, the middle groove on the third toe plantar surface hadthe best effects of sand flow fixation, under which the forces within the sand particle groupspresented the grid-patterned stable tight distribution.Reversing engineering software Geomagic studio and the point cloud filteringcapabilitie in Digital design module of3D design software Catia were combined with thesurface fitting module in MATLAB to model the three typical surfaces of the third toe,and theⅣ toe plantar surface. An ellipsoid model was used to fit the heel spherical cap by using thenonlinear regression module of SAS software because the heel spherical cap looked like a partof an ellipsoid from appearance. The plantar surface morphology of ostrich foot weresuccessfully transformed from the biological model to the mathematical model. As a result,The forefoot gradual surface, the middle groove of the third toe plantar surface and the Ⅳ toeplantar surface mathematical equations were obtained as below: Z=428.2+1.26x+2.317y+0.0066x2-0.00023xy+0.01735y2, R2=0.9485;Z=340.7-2.208x+3.016y-0.017x2+0.0009xy+0.04339y2, R2=0.9607;x2/47.47082+y2/30.18522+(z+70)2/702=1, R2=0.95;Z=307.2+0.28x+1.081y+0.003587x2-0.0009xy+0.0213y2, R2=0.953.According to the features of three typical surface on the third toe and the connectiontype among three typical curved surface, a bionic wheel drum wheel surface travelling on sandin three-dimensional design software Catia with the respect of structural characteristics ofMars Patroller and the mechanism for travelling on sand,as well as the usage of Bionic theory..The high-precision, low-load wheel loam slot test system were adopted to test the physicalwheel model. Traction, slip rate and wheel rut were studied for comparing theperformance of ordinary wheel and bionic wheel, linking. With the help of discrete elementsoftware PFC, the wheel/soil simulation system were built the dynamic numerical simulationon the bionic wheel. The results of dynamic numerical simulation and analysis on the tractionand subsidence resistance of the bionic drum wheels were compared with the testing result inwheel/soil system. the results show that, in the same conditions, bionic drum wheel surfacecan increase the traction performance with about300%when compared with ordinary drumwheel surface.Using high-speed camera system and Simi Motion analysis software, the angularvariation rule between the third toe and the Ⅳ toe plantar of ostrich foot was explored duringthe process of touching and leaving ground when running on different angles slope. It is aimedat to seek the optimal angle between two toes when interacting with sand. Taking advantage ofthe plantar surface on Ⅳ toe and optimal angle between two toes to build the bionic prototypewith the help of the engineering bionics technology. The bionic wheel monomer on gradualsurface of bionic drum wheel was designed in Catia software. Then, make monomers weregiven a reasonable distribution gradual surface of the bionic wheel to complete Mars Patrollerbionic wheel structure design. Experiments were conducted in soil-bin tostudy the traction andanti-slip properties of the bionic wheel. The results show that, under the same experimentalconditions, Mars Patroller wheel with a bionic round prickly thorn has a better throughperformance than that wheel without a bionic round prickly thorn.