Mechanical modeling and analysis of the knot-tying in cornea grafting microsurgery

According to the images of surgeons' clinic operations, the movements of knot-tying in clinic surgery were decomposed into 4 main procedures. The mechanical model of knot performing was constructed and simplified into a symmetrical form of tensed force. Considering critical slip condition, friction between sutures as well as node-to-node contact for the effect of tensile force, the static equilibrium equations for knot s movements were constructed and the feasible rang of force exerting on it was obtained. Based on it, a motion equation was constructed to represent the tracks of sutures' end and its simulation was performed. By comparing simulations under different tensile force conditions, the optimal path of end-operator was planned on cornea grafting microsurgery robot for tying knot.