A Set of Basic Movement Primitives for Anthropomorphic Arms

Abstract

According to increasing demands on accomplishing the complicated tasks anthropomorphic arms are facing and the diversity of the anthropomorphic arm platform, a novel and unified task-motion planning method for anthropomorphic arms is investigated in this paper. Firstly, inspired by the discovery of the movement primitive in human arm motion from Neurophysiology, a three-level task-motion planning framework “joint space-movement primitive space-task space” is proposed, which can plan and describe complicated tasks in a flexible modular manner. Next, a human arm triangle space is proposed to intuitively represent the instantaneous status of the movement primitive. Based on that, the kinematics of the anthropomorphic arm containing human arm triangle space is established, which lays a solid foundation for the complete control of the motion process for arms. Then, four basic movement primitives, “moving on a working plane”, “switching different working planes”, “translating the hand”, and “rotating the hand about a fixed axis”, are designed according to the composition motion principle of rigid body and a human arm motion principle that the human arm tends to move on a fixed plane. All kinds of the complicated tasks can be achieved by combining these four movement primitives appropriately. Because the human arm triangle space is structure-and-dimension-independent of the specific arm, the proposed method is applicable to different anthropomorphic arm platforms, thus has the advantage in generality. Finally, the superiority of this method is verified by comparing with a traditional method.