Hyper-Redundant Manipulator Capable of Adjusting Its Non-Uniform Curvature with Discrete Stiffness Distribution

Seongil Kwon,Keri Kim,Yonghwan Moon,Jeongryul Kim

doi:10.3390/app12010482

Abstract

Hyper-redundant manipulators are widely used in minimally invasive surgery because they can navigate through narrow passages in passive compliance with the human body. Although their stability and dexterity have been significantly improved over the years, we need manipulators that can bend with appropriate curvatures and adapt to complex environments. This paper proposes a design principle for a manipulator capable of adjusting its non-uniform curvature and predicting the bending shape. Rigid segments were serially stacked, and elastic fixtures in the form of flat springs were arranged between hinged-slide joint segments. A manipulator with a diameter of 4.5 mm and a length of 28 mm had been fabricated. A model was established to predict the bending shape through minimum potential energy theory, kinematics, and measured stiffnesses of the flat springs. A comparison of the simulation and experimental results indicated an average position error of 3.82% of the endpoints when compared to the total length. With this modification, the manipulator is expected to be widely used in various fields such as small endoscope systems and single-port robot systems.

Highlights

Academic Editor: Dario RichiedeiMinimally invasive surgery (MIS) is common medical practice owing to its convenience for surgeons and reduced patient trauma and recovery time [1,2,3]
The specifications of the manipulator targeted in this study are as follows: a 2-degrees of freedom (DoF) bending motion should be possible to realize intuitive movement; elastic fixtures a 2-DoF bending motion should be possible to realize intuitive movement; elastic fixtures should be placed in the middle of segments; there must be a hollow through which surgical should be placed incan the pass
We proposed a special shape of flat spring to meet the or limit degrees of freedom

Summary

Introduction

Invasive surgery (MIS) is common medical practice owing to its convenience for surgeons and reduced patient trauma and recovery time [1,2,3]. The internal structure of the human body is diverse, and there are cases in which a surgical tool may have to pass through narrow and winding paths. In order to reach the target position and perform the necessary operations, we require surgical tools with flexible bodies [4]. Hyper-redundant manipulators used in MIS take an underactuated form that transmit power using tendons from the outside. This is advantageous for miniaturization and entering narrow and winding passages, due to its flexibility

Methods

Results

Discussion

Conclusion