Experimental Research And Modeling Of The Steering Terramechanisc For Lunar Rovers

Wheel of the lunar rover, which contacts directly on the moon, can not onlycarry the whole weight of rover, generate traction force and feedback the necessaryterrain information on the moon, but also has very important influence on movingability, steering flexibility and adaptability on terrain. The research of steeringmechanics has vital significance to improve the performance and stability ofplanetary exploration rover. Predicting the wheel-soil interaction performanceaccording to terramechanics knowledge is of great importance to the mechanicaldesign/evaluation/optimization, dynamics simulation, soil parameter identificationand control of planetary rovers.The experimental research of the effect on the terramechanics based on thewheel configuration parameters and wheel operation parameters was carried on byusing single-wheel test bed for wheels. Aim at four main wheel configurationparameters, including wheel width, wheel radii, lug height, lug numbers, based ondifferent design parameters, the effect of the wheel configuration parameters on thewheel sinkage and wheel steering torque was performed. The influences of verticalload and steering velocity were also studied. Experimental results are shown withfigures and tables for analyzing the wheel’s driving performance in deformable soiland drawing conclusions. It is found that the increase of the wheel width lead to theincrease of the steering torque and thereby severely affect the flexibility inmaneuvering the steering. The experimental results and conclusions are very usefulfor optimization of wheel mechanical design and improvement/verification ofwheel-soil interaction mechanics model.Based on the experiment, the subject has measured the sand parameters, such ascohesion modulus, friction modulus, subsidence index, inside cohesive force and theinternal friction Angle et. Based on the classical basic stress model, has establishedintegral models for sinkage and torque while the wheel is steering, the sinkagemodel has solved the problem that subsidence index is unsuited to the loose sand byturning the subsidence index into a function, the concept of the effects of bulldozingand cavitation is introduced into the torque model, and the model deduced by theoryis modified; And the mechanical model can predicted the experiment data well.