In this chapter, we introduce modeling and control for wheeled mobile robots and tracked vehicles. The target environment is rough terrains, which includes both deformable soil and heaps of rubble. Therefore, the topics are roughly divided into two categories, wheeled robots on deformable soil and tracked vehicles on heaps of rubble.
After providing an overview of this area in Sect. 50.1, a modeling method of wheeled robots on a deformable terrain is introduced in Sect. 50.2. It is based on terramechanics, which is the study focusing on the mechanical properties of natural rough terrain and its response to off-road vehicle, specifically the interaction between wheel/track and soil. In Sect. 50.3, the control of wheeled robots is introduced. A wheeled robot often experiences wheel slippage as well as its sideslip while traversing rough terrain. Therefore, the basic approach in this section is to compensate the slip via steering and driving maneuvers. In the case of navigation on heaps of rubble, tracked vehicles have much advantage. To improve traversability in such challenging environments, some tracked vehicles are equipped with subtracks, and one kinematical modeling method of tracked vehicle on rough terrain is introduced in Sect. 50.4. In addition, stability analysis of such vehicles is introduced in Sect. 50.5. Based on such kinematical model and stability analysis, a sensor-based control of tracked vehicle on rough terrain is introduced in Sect. 50.6. Sect. 50.7 summarizes this chapter.
Experiments of wheeled rovers in a sandbox covered with loose soil
Author Field Robotics Group, Tohoku University
Video ID : 185
The lunar and Martian surfaces are covered with loose soil, and the wheels of rovers can get stuck on such surfaces. To avoid the problem, it is necessary to conduct thorough investigations into the contact and traction mechanics between the wheels and the soil. To this end, we conduct various experiments using wheeled rovers in a sandbox covered with loose soil. In the experiments, the slippage and sinkage of wheels with various geometries are measured. Based on these experimental observations, analysis and modelling of the motion behavior of wheels ensued.