The Combination of Knee Limiting Braces and Origami Structures

In ACL postoperative rehabilitation, standardized knee motion-limiting braces often fail to adapt to individual leg morphology differences, which hinder rehabilitation and user experience. To address these issues, this study aims to propose a dynamically conforming arc-Miura fold-inspired design to replace conventional skin-fitting straps. The research first elaborates on the overall design concept, highlighting two key advantages of the arc-Miura structure: improved anatomical conformity (adapting to heterogeneous skin surfaces via controlled deformation) and mechanical efficiency (evenly distributing forces through tessellated geometry). Subsequently, the interface design between the Miura fold and the rigid brace frame is detailed, including a U-shaped groove for smooth kinematic transition and a triangular linkage mechanism with modular scalability and fold-driven actuation. The motion mechanism of the arc-Miura structure is systematically analyzed: based on a single input parameter (folding angle A1B1), the correlation formulas between A1B1 and key parameters (arc radius Ri, structural span L, cumulative angle nx) are derived, and the ring-forming characteristics in the fully folded state are explored, leading to the adoption of a semi-arc structure to avoid excessive overlap. Parameter optimization is conducted by investigating the influence of core parameters (a1, a2, I1, I1') on crease distribution, and constraint conditions for thigh and calf adaptation are established. Through algorithm optimization, structural parameters suitable for the thigh and calf are obtained, with their performance ranges meeting ergonomic requirements. This study systematically explores the integration of origami structures with knee-limiting braces, addressing the limitations of conventional braces in dynamic conformity and mechanical efficiency. Through design, analysis, optimization, and prototype fabrication, it provides a novel solution for improving knee brace ergonomics, demonstrating the feasibility of origami engineering in optimizing wearable device performance.