Kinematics and tip-over stability analysis for a mobile humanoid robot moving on a slope

When a mobile robot performs some special tasks, such as carrying a heavy load, moving on a slope or rough terrain, particularly contacting with the environment, it may become unstable even overturn. First, the paper presents a mobile humanoid robot whose upper human-like body is mounted on the mobile platform supported by three wheels (two driving wheels and one caster wheel) and subjected to nonholonomic kinematic constraints. Then the kinematics of the mobile platform and the upper human-like body are studied and tip-over stability of the motion on a slope is analyzed. Following that, two cases are studied with different postures of the upper body and two arms in accordance with the motion on a slope. Computer simulations are carried out and the influences of different robotic postures on the tip-over stability are analyzed through simulation results.