Gravity Canceled Flexible Joint Mechanism(Mechanical Systems)

Abstract

In this paper, we propose a mechanism which is named "gravity canceled flexible joint," since a passive flexible joint attracts attention by its collision safety. Manipulators with a passive flexible joint are expected to work in a human environment. However, manipulators with the passive flexible joint have some problems. One is that there is steady position error because of displacement of flexible joints by self-weight. Moreover, the manipulator power and the back drivable range are reduced by self-weight. Mechanical self-weight compensation become efficient for overcoming this problem. Therefore, this paper proposes the passive flexible joint with self-weight compensation mechanism that equips the features with compactness and durability. In order to satisfy these requirements, this research focuses on a end cam. By using the end cam, nonlinear rotational spring is able to design from determining a pressure angle of end cam. Both the self-weight compensation and the passive flexibility are achieved by end cams. From position control experiments, it is clarified that the proposed mechanism can compensate steady position error and showed utility as a joint mechanism.