Steep slope climbing using feet or shins for six-legged robots

Two methods for a six-legged robot of climbing steep slope are proposed. In the first method the robot lands its feet. Four legs land abreast on the lower side of the slope. Two legs land abreast on the upper side. The outer pair of the lower legs and one upper leg move together, and the inner pair of the lower legs and the other upper leg also move together. The robot walks on the slope in all directions like tripod gait. Because two of the lower legs are always placed below the robot's center of gravity, this method can support the robot stably. The second method uses the robot's shins to increase ground contact area. Two lower legs and two upper legs land their shins on the slope. These legs push the body upward. The remaining two legs land their feet and make a space under the body for the above-mentioned four legs to step forward. Owing to larger friction force, the second method allows the robot to climb steeper slope than the first method. The slope climbing ability of these methods is tested using three kinds of slope: artificial grass, nonslip mat and desktop wood.