| In the Earth’s environment, it is difficult to accurately simulate the interaction relationsof Wheel and lunar soil and traction performance test of lunar rover under the complexenvironment of the moon surface. For this reason, this essay proposes the establishment ofthe dynamic simulation system of the interaction between irregular structure wheel and looselunar soil simulant to solve the traction performance problems when wheel runs on the lunarsoil and to provid an important theoretical and technical basis for further research andoptimization of wheel configuration of deep space exploration vehicles (such as rovers).This essay takes the rectangular lug wheel as the prototype design.Based on lug themain contact site between wheel and soil, the foot toenail of ostrich is selected as the bionicprototype, which is the key part for ostrich to run on sand swiftly. With the help of reverseengineering technology and the principle of bionics, three typical edge characteristic curvesof the ostrich foot toenail can be obtained, which are then closed to a plane. By stretching theplane along the surface of the wheel, a single bionic lug can be designed And then, along therim surface, all18lugs are to be formed, and the design of bionic wheel is completed.Using Clump command in discrete element analysis software PFC2D and the FISHlanguage, a two-dimensional dynamic simulation system of the interaction between irregularstructure wheel and loose lunar soil simulant is established. Through the comparisonbetween rectangular lug wheel experiment and simulation results, it is verified that thesimulation system can meet the requirement of accuracy. And traction simulation results ofthe rectangular lug wheel and bionic lug wheel show that, under condition of the same sliprate, the former has bigger traction and that when the slip rate is50%, compared with thelatter, the tractive force of the former will increase by5.2%. At the same time, the former hasa better effect of consolidating soil, which provides more excellent adhesion property for themovement of wheel. For the subjects with invariant cross section structure, thetwo-dimensional simulation system can be used to make a preliminary research andexploration. Based on the theory of terrain vehicle mechanics the interface codes, and thecombination of embedded FISH language in PFC3D, the computer aided design softwareCATIA and3D Discrete Element Method simulation software PFC3D, finally, the dynamicsimulation system of interactions between rigid wheel with irregular structure and looselunar soil stimulant was established, and the reliability and validity of the wheel modelestablished by CATIA is checked. The dynamics simulation between the rectangular lugwheel and lunar soil interaction, is comparedwith laboratory soil test, it shows that, theresults of both3D dynamic simulation and laboratory soil test are basically consistent. Thisarticle also improves the function of three-dimensional dynamic simulation system,establishes three different types of Lunar soil surface environment and Analyzesobstacle-navigation performance from a qualitative perspective.At the same time, by compiling FISH language and using PFC3D IV module,post-processing functions on three-dimensional dynamic simulation system is expanded anddeveloped. Comparative simulation of Bionic wheel and rectangular wheel is carried outusing the three-dimensional dynamic simulation system. Simulation results show that Bionicwheel has better traction and performance against subsidence, which is more obvious in thelarger slip rate and that it has better smoothness resistance. In addition, this essay also raisedthe multiscale numerical methods,using full matrix and degradation matrix instead ofparticles, which is quick, effective and instructive. Meanwhile, through Delphi software userinterface is established toinitially improve the functionality of the simulation system, andprovide theoretical basis and technical support for a further study of wheel and soilinteraction. |
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