Analysis of Effects of Leg Inertia Distribution on Contact Stability and Dynamic Performance During Bipedal Walking

Abstract

This paper analyzes the effects of leg inertia distribution on contact stability and dynamic performance during bipedal walking. Recently, to ensure that the leg inertia distribution is mainly concentrated on the hip, biped robots have been developed with legs designed based on the design principle of placing the leg actuators near the pelvis. It is often mentioned that the dynamic performance of biped robots is improved by concentrating leg inertia distribution on the hip. However, it is not clear which aspect of the dynamic performance is improved and how it affects contact stability during walking. In this study, to analyze the improved dynamic performance and effects on the contact stability by concentrating the leg inertia distribution on the hip, the contact condition margins and maximum walking velocity for each model with various leg inertia distributions are calculated using the estimated contact wrench in walking simulations. The Linear Inverted Pendulum Model and the centroidal dynamics with full-body kinematics model, which have different degrees of model accuracy, are used as walking pattern generation models for walking simulations. As a result, it is confirmed that the contact stability and dynamic performance are improved as the leg inertia distribution is concentrated on the hip from the simulation results.