New Adaptive Segmented Wheel for Locomotion Improvement of Field Robots on Soft Terrain

In this paper, a new adjustable segmented wheel is proposed whose platform is composed of a complex closed-loop scissor mechanism wrapped over adjustable spokes. The new platform composed of four proposed wheels is specified to avoid halting, to increase traction force and to adjust body orientation while interacting soft or composite terrains. The soil contact model (SCM), extended from Bekker’s theory is implemented to derive the wheel-soil interaction formulations. Furthermore, the Lagrange approach is used to derive the unmanned ground vehicle (UGV) dynamics including interaction forces. The best configurations of adjustable wheel are tabulated according to the terrain properties and the motion types. Finally, the proposed UGV is compared with a typical ordinary UGV to investigate traction forces and halting avoidance. Based on the simulation results and primary tests of the experimental setup, it can be inferred that this new mechanism can effectively adapt itself to different terrain conditions in order to pass the soft concave regions, climb the soft obstacles and move on the composite terrains.