WheTLHLoc: Small-Scale Hybrid Locomotion Robot With Stair Climbing Capability

Abstract This paper discusses the theoretical analysis and the experimental validation of the step and stair climbing capability of wheel-track-leg hybrid locomotion (WheTLHLoc), a small-scale hybrid locomotion robot with overall size of 450 × 350 × 130 mm and maximum payload of 0.5 kg. The architecture of this robot combines two tracks, two rotating legs, two actuated wheels, and two passive omni wheels. The robot is capable of performing different locomotion modes: wheeled locomotion on flat and compact grounds with maximum speed of 0.9 m/s, tracked locomotion on soft and yielding terrains with maximum speed of 0.1 m/s, mixed use of tracks, legs, and wheels to overcome obstacles. In particular, the process of step and stair climbing is analyzed considering static stability and non-slipping conditions. The experimental campaign on the first prototype has confirmed the effectiveness of the proposed climbing maneuver for steps up to 165 mm and the operative flexibility of the WheTLHLoc robot.