Design of a rehabilitation mechanism based on linkage mechanisms

Abstract. To help patients with unilateral limb movement disorders recover to normal life as soon as possible, this article, based on the principles of institutional innovation and analysis of existing designs, proposes the design of a novel linkage-type rehabilitation mechanism. This mechanism is designed to assist users in completing self-passive training by driving the affected limb with the healthy limb. The core of the mechanism is a single-degree-of-freedom linkage motion chain, which integrates a leg mechanism, an arm mechanism, and a back transmission mechanism. The main work of this paper includes the following: first, proposing the overall design concept of the rehabilitation mechanism and clarifying the synergistic working principle of each subsystem; second, designing an eight-bar leg mechanism based on human factor engineering data, whose end trajectory closely fits a normal gait trajectory; next, designing a six-bar arm mechanism that can work in coordination with the leg mechanism and a back transmission mechanism that ensures the cranks of the leg and arm mechanisms operate at a constant speed; and finally, conducting model simulation analysis and prototype experiments to verify the design. The results show that the rehabilitation mechanism can complete the predetermined coordinated movements. The contribution of this article is to provide a novel design for a rehabilitation mechanism, explore different development directions for similar products, and offer new ideas for the design of human–machine collaborative rehabilitation mechanisms.