Abstract
Multi-DOF manipulators consist of many actuators. Then, it is difficult to increase output power without they becomes heavier. As a measure for this problem, several mechanisms called "Weight compensation system" have been developed. But these mechanisms cannot be installed in the manipulators which have the roll axis located between two pitch axes. The reason is that there is no reference point of gravity direction in such linkage. In this paper, we propose the new weight compensation mechanism used parallel motion mechanism with bevel gears. It has reference point of gravity direction that is independent from rotation around roll axis, and it is able to be installed the roll axis between two pitch axes.
