Proposal of Experimental Reproduction Method of Variable Gravity and Gait Analysis of Biped Robot

Paper number

IAC-11,A1,6,16,x11910

Author

Mr. Yusuke Matsumoto, Keio University, Japan

Coauthor

Mr. Tatsuhiko Ikeda, Keio University, Japan

Coauthor

Dr. Terumasa Narukawa, Keio University, Japan

Coauthor

Dr. Masaki Takahashi, Keio University, Japan

Coauthor

Dr. Shin Yamada, Japan Aerospace Exploration Agency (JAXA), Japan

Coauthor

Dr. Hiroshi Ohshima, Japan Aerospace Exploration Agency (JAXA), Japan

Coauthor

Prof. Meigen Liu, Keio University, Japan

Year

2011

Abstract

In the future, human plan to go to the moon or other planets. When astronauts construct lunar base and live on the moon, one of the biggest differences between the moon and the earth is the gravity. Due to the difference of the gravity, walking becomes difficult and astronauts might fall to the ground, possibly damage the life support system. In order to reduce the risk of falling, it is necessary to analyze the influence of gravity to walking. 

 This paper proposes method to simulate walking under variable gravity on the earth, which can be applied to astronauts training. Major method to simulate walking under variable gravity is lifting of the hip (Lifting method). However, lifting method has a problem that only body is supported and four limbs are not supported. Because four limbs are powered by normal gravity, lifting method is not enough to simulate walking under variable gravity. In order to analyze the influence of lack of leg support, this paper compares the gait of lifting method and the gait under variable gravity, based on a compass-like biped robot’s passive walking. Furthermore, we propose a new method (Hybrid-support method) to simulate walking correctly under variable gravity. In addition to lifting method, legs are actuated from hip and ankle joints to support the mass against the gravity. With hybrid-support method, it is shown that simulation results conform to the gait under variable gravity.
 
 This study also aims at analyzing the influence of gravity to walking under variable gravity by passive walking. Passive walking is phenomenon that the biped robot walks down on a slight slope without active control or energy input. This means that passive walking is powered only by gravity. Therefore, passive walking is considered to be the best method to analyze the influence of gravity to walking. This study uses a simple compass-like biped robot. The gait of the robot is influenced by varying the gravity. From the simulation results, it is shown that the length of stride is not influenced by gravity but gait speed is proportional to the square root of gravity.

 In conclusion, this paper proposed hybrid-support-method to simulate the gait under variable gravity and analyzed the influence of gravity to walking.

Abstract document

IAC-11,A1,6,16,x11910.brief.pdf

Manuscript document

(absent)