Abstract:Abstract:Objective This paper proposed the pushing transmission models in the tendon-sheath actuation endoscopic flexible instrument in push-push configuration and explored the key influencing factors. Methods The force and displacement transmission models were built and simulated. For validation, a tendon-sheath transmission-testing platform was designed. Besides, the influencing factors, such as the transmission velocity,the ratio of the tendon-sheath diameters, the radius of the curvature, are explored using this setup. Results There are nonlinear phenomenon in the force and displacement transmission. The model simulation result accord quite well with the experiment result. Above-mentioned factors have great effect on the force transmission, smaller effect on the displacement transmission. Conclusions Proposed models can give reliable predictions of the force and displacement transmission in the endoscopic flexible instrument in push-push configuration to provide the doctors the end feedback, which will ensure the safe operation and improve the surgical result. For better design and control of the flexible instrument, the transmission velocity, the ratio of the tendon-sheath diameters, the radius of the curvature must be considered.