Redundant Multi-DoF Robot Arm Co-operation Through the Body Integration System

The human arm has seven DoF. If the human arm were more redundant, it would improve workability. However, intuitive manipulation of redundant arms is difficult due to the complexity of the input system or the limitations of the human arm. In this study, we constructed a system in which multiple operators integrate their bodies to intuitively operate a redundant multi-DoF robotic arm. The robotic arm was assembled by connecting two arms, and the roles of each section –distal arm and proximal arm– were assigned to different operators. First, vibrotactile feedback methods to the users based on the operation movement were investigated to compensate for the recognition of the partner’s movement. Three types of feedback methods —the actions of both oneself and one’s partner, the actions of the partner, and none— were compared in order to improve the body awareness. It was shown that feedback of the movement from the partner who operates the proximal robotic arm significantly enhanced the sense of body ownership. Then, the proposed co-operation of the redundant robotic arm was evaluated in the workability. Two types of manipulation methods —a single-operator system that switched the target robotic arm and a multi-DoF body-integration system used by two people— were compared through an object-manipulation task involving obstacle avoidance. It was shown that the two-person co-operation through body integration system to be faster than the single-person operation.