Leg-wheel hybrid locomotion for multi-legged robot

Leg-wheel hybrid locomotion on rough terrain for a hexapod robot is realized by continuous transition between wheeled and legged locomotion based on sensor feedback. In basic positioning on a flat surface, the robot is supported by three legs and moves using its wheels. Upon sensing an obstacle, the robot's support and swing legs change as a tripod gait to cross over the obstacle. We define the three dimensional model of the motion on a slope for stability estimation, and its analysis indicates that the maximum obstacle height depends on the robot's height and the slope gradient. Even if the slope is steep, the robot can climb over a higher step on it by moving the robot's center of gravity (COG) based on the analysis. The experimental results on ASTERISK H confirm the advantage of proposed motion by comparing to the fixed COG motion.