Tensegrity Wrist Mechanism using Three Layers of Rigid Bodies and Strings.

The paper begins with a literature survey on musculoskeletal structure of human wrist, which has three different functions of layer and joints such as distal radius/ulna layer as a mechanism base, radio-carpal joint and mid-carpal joint. Based on the considerations of anatomical structure of the human wrist, a new type of wrist mechanism is proposed by stacking up the structures of two class-one tensegrity systems sequentially. A few advantages obtained by using the tensegrity structures are found such as it is lightweight, it shows a compliance property when the external forces are exerted, and it does not have any contacts between rigid bodies stacked in the proposed wrist mechanism. Finally, we show that the tensegrity wrist acts like the biaxial universal joint having both flexion/extension and abduction/adduction.