Realization of Surfing Robot with Approximate ZMP Estimation Method without Force Sensor (A Study on the Standing Stability of Robot Under Environmental Change in Direction of Gravity without Force Sensor)

Abstract

This study proposes how a humanoid robot can perform surfing without force sensor. Usually, it is impossible to control surfing robot only with its center of mass information, because the change of gravity direction cannot be measured without force sensor. However, this study attempts to clarify the possibility of the control for the humanoid surfing without force sensor by using estimated joint torque information from its motor current. Several control methods are proposed to realize the surfing robot without force sensor by using approximate ZMP estimation method based on the motor current information. These experimental results show not only contribution of sensorless control method but also interesting stability discussions that consists of both static stability and dynamic stability problem. All of both cases are for maintaining its standing stability under change in direction of gravity.