Analysis of tendon tension and hysteresis by tendon twisting and development of anti‐twist tendon mechanism of robotic surgical instruments

Abstract

Background: Control of the joints of robotic surgical instruments is difficult owing to hysteresis, and tendon twisting due to axial rotation of surgical tools also causes hysteresis. Therefore, a new mechanism is needed to prevent tendon twisting.Methods: Tendon tension and hysteresis change were analysed by observing the movement of the joint depending on whether the tendons twisted for the same input signal. An anti-twist tendon mechanism to prevent twisting was developed.A 3-mm needle driver applied with the proposed mechanism was manufactured. Results:The anti-twist mechanism makes no tension change because of twisting or friction between the tendon and the system, that is, the operating performance was the same regardless of rotation. Conclusion:The proposed mechanism has been verified and can be applied to small surgical instruments 3 mm in size. These findings can be applied in the development of instruments for precise surgeries such as microsurgery.