Normalized energy stability margin and its contour of walking vehicles on rough terrain

Some stability criteria for walking vehicles on rough terrain are discussed. Several criteria for stability margin have been proposed previously and they can be roughly divided into three categories. The paper compares them with each other and concludes that a stability criterion based on energy consideration is the most reasonable for practical use through simple experiments. The existing stability margin is apparently inadequate because it varies with weight of the vehicle with the same posture, while weight doesn´t affect its resistance to a tumble. Therefore, an improved stability margin normalized by weight is proposed. At the same time, a helpful tool to derive the desirable posture for walking vehicles is described which can maximize the proposed stability margin on rough terrain.