Design of 22-DOF pneumatically actuated upper body for child android 'Affetto'

Abstract

Child robots have been used in a lot of studies on human-robot social/physical interaction because they are suitable for safe and casual experiments. However, providing many compliant joints and lifelike exteriors to enhance their interaction potential is difficult because of the limited space available inside their bodies. In this paper, we propose an upper body structure that consists of slider crank and parallel mechanisms for linear actuators and serial mechanisms for rotary actuators. Such combinations of several joint mechanisms efficiently utilize the body space; in total, 22 degrees of freedoms were realized in an upper body space equivalent to that of an 80cm tall child. A pneumatic drive system was adopted in order to fully verify the behavioral performance of the body mechanism. The proposed redundant and compact upper body mechanism can be a platform for testing the effectiveness of future exteriors for the little child android 'Affetto', which was developed in order to integrate several key characteristics for achieving advanced human-robot interaction.