Slipknot-gauged mechanical transmission and robotic operation.

Abstract

Mechanical transmission is essential in force-related activities ranging from the daily tying of shoe laces¹ to sophisticated surgical² and robotic operations^3,4. Modern machines and robots typically use complex electronic devices designed to sense and limit force⁵, some of which still face challenges when operating space is limited (for example, in minimally invasive surgeries)⁶ or when resources are scarce (for example, operations in remote areas without electricity). Here we describe an alternative slipknot-based mechanical transmission mechanism to control the intelligent operation of both human and robotic systems. Through topological design, slipknot tying and release can encode and deliver force with a consistency of 95.4% in repeating operations, which circumvents the need for additional sensors and controllers. When applied to surgical repair, this mechanism helped inexperienced surgeons to improve their knotting-force precision by 121%, enabling them to perform surgical knots as good as those of experienced surgeons. Moreover, blood supply and tissue healing after surgery were improved. The mechano-intelligence exhibited in slipknots may inspire investigations of knotted structures across multiple length scales. This slipknot-gauged mechanical transmission strategy can be widely deployed, opening up opportunities for resource-limited healthcare, science education and field exploration.