Study On The Obstacle-climbing Capability Of Lunar Rover Based On Half-rotating Mechanism

The kinematics analysis was done according to the characteristics of the lunar rover basedon half-rotating mechanism. The coordinate systems of single wheel-leg and the whole vehiclewere established; the coordinate transformation matrixs of forward kinematics was deduced,and the undulation of lunar rover was analyzed.The maneuverability of lunar rover was studied. The force models of lunar rover on plains-walking and climbing-walking were established. With the forward kinematics analysis, thenormal forces between the wheel-legs and ground were simulated. Then the steering principlewas described and the forces of steering-walking were simulated.The obstacle-climbing capability on hard land was studied. A new judging standard of theobstacle-climbing capability was presented. Pointed out that the larger the friction feasibleregion, the stronger the obstacle-climbing ability, and when the friction feasible region thewheel-legs suffered did not exist, the mechanism would not have the obstacle-climbingcapability under the initial conditions. The obstacle-climbing force model under frictionconstraints was established when giving the slope angle and obstacle height, the single wheel-leg and two wheel-legs forward obstacle-climbing capability were simulated through themethod of finding the wheel-leg’s friction feasible region.On the basis of the existed studyof Bekker compaction model, Janosi shear model, andTerzaghi bear model, the relationships of the sinkage, vertical load and the driving force wereanalysed.The obstacle-climbing capability on soft land was studied. The error that the width ofsinkage caused can be eliminated by iteration, and whether the solution space region ofmechanics exist or not would not be influenced by the error that the width of sinkage caused.Combined with kinematics analysis and the analysis processes on hard land, the single wheel-leg and two wheel-legs forward obstacle-climbing capability on the soft land were simulatedthrought the method of iteration using the width of sinkage.