Visual Representation of the Compactness of a Stephenson-II Six-Bar Linkage Exoskeleton Using Solution Region Synthesis Theory

Abstract

With the increase of sensors and actuators, the size and weight of intelligent robots are becoming larger and bulkier. Especially for wearable robots, excessively large exoskeleton dimensions will reduce the portability and the wearing experience for patients. In this paper, we propose an evaluation criterion for describing the spatial compactness of the hinge points in a multi-link mechanism and design a compact Stephenson-II linkage exoskeleton based on the solution region synthesis theory. We combine the method of solution regions, the single value mapping method of the Burmester curve, and the proposed compactness evaluation criteria, to achieve the visual representation of the compactness of the Stephenson-II linkage. Under the guidance of the proposed method, a linkage finger exoskeleton based on four natural grasping positions was designed, and a rigid-soft parallel hand device was developed. A series of kinematics/dynamics simulations and gripping experiments are conducted to verify the mechanical properties of the hand device. The approach to visualize the spatial compactness of the Stephenson-II six-bar linkage in this paper can offer insights into the optimization of the spatial structure of other intelligent robots.