Design of New Drive Mechanism for Dynamic Movement of Humanoid Robot Legs

Abstract

In this study, we propose a novel design method for the humanoid robot leg, aiming to enhance its capabilities in performing dynamic, human-like movements. Performing human-like movements means being able to move flexibly in environments designed for humans. The proposed design method utilizes a Quasi-Direct-Drive (QDD) motor with higher efficiency compared to conventional high reduction actuator, and the driving part of the joint composed of a pair of differential gears adopts a Double Actuator - Double Joint method, allowing for higher torque output than that of a Single Actuator - Single Joint. The configuration of this driving parts is characterized by positioning all actuators above the knee joint, which ensures the center of mass is situated as close to the center of the body as possible. Additionally, the driving range of each joint is designed to be similar to that of a human. Applying our mechanism to a single leg, we conducted a simulation experiment to observe changes in actuation torque in response to variations in mass distribution within the driving part. Furthermore, we discovered that the use of differential gears allows for more efficient power distribution in the motor compared to traditional robot legs.