Kinematic Model Improvement of multi-degree-of-freedom Robotic Surgical Tool that Consists of Elastic Materials for further Accuracy

Abstract

To enhance surgeons’dexterity in minimally invasive surgery, the authors have developed a four degree-of-freedom robotic surgical tool that has diameter of 3.5 mm using superelastic materials in previous study. The most notable feature of the tool is that the mechanism consists of multiple elastic elements, thus the tool has simpler and smaller structure than that of conventional robotic surgical tools. The developped robotic surgical tool showed promising results in evaluation, however, the control accuracy was found to be diminished when the tool bends in multi-degree-of-freedom. We have identified the cause of this issue as a mismatch of kinematic model and actual model because the current kinematic model was implemented without considering the interaction between springs. In this study, we applied Shooting method to solve the shape calculation on segmented mechanism model, and compared the results with FEM analysis. The results showed a better accuracy with the proposed method.