Laser-Profiled Continuum Robot with Integrated Tension Sensing for Simultaneous Shape and Tip Force Estimation

Abstract

The development of miniaturised continuum robots has a wide range of applications in minimally invasive endoluminal interventions. In order to navigate inside tortuous lumens without impinging on the vessel wall and causing tissue damage or the risk of perforation, it is necessary to have simultaneous shape sensing of the continuum robot and its tip contact force sensing with the surrounding environment. Miniaturisation and size constraint of the device have precluded the use of conventional sensing hardware and embodiment schemes. In this paper, we propose the use of optical fibres for both actuation and tension/shape/force-sensing. It uses a model-based method with structural compensation, allowing direct measurement of the cable tension near the base of the manipulator without increasing the dimensions. It further structurally filters out disturbances from the flexible shaft. In addition, a model is built by considering segment differences, cable interactions/cross talks and external forces. The proposed model-based method can simultaneously estimate the shape of the manipulator and external force applied onto the robot tip. Detailed modelling and validation results demonstrate the accuracy and reliability of the proposed method for the miniaturised continuum robot for endoluminal intervention.

Advancement of Flexible Robot Technologies for Endoluminal Surgeries

“…Moreover, the use of optical fibers for both actuation and tension, shape, and force sensing of a continuum manipulator was presented. A model-based estimation method has been developed to simultaneously estimate the shape and tip force [213]. When sensors are directly embedded in a surgical instrument, maintaining a small size, ease of sterilization, and robustness are tasks that are still difficult to attain.…”

FBG-Based Estimation of External Forces Along Flexible Instrument Bodies

“…The problem of estimating externally applied forces on robotic manipulators is not new. There has been an abundance of works carried out on rigid link robots (Jung et al, 2006;Colome et al, 2013;Daly and Wang, 2014;Hu and Xiong, 2018), and more recently, on soft/continuum robots (Yasin and Simaan, 2020;Sadati et al, 2020;Xu and Simaan, 2010;Gao et al, 2020). Regarding the latter, most of the previous works focused on estimating the contact force at the tip of the manipulator/instrument, rather than along the whole body.…”

Design of 3D-Printed Flexible Joints With Presettable Stiffness for Surgical Robots

“…Moreover, stiffness control of flexible continuum manipulators based on kinematics and statics model [10] or the force feedback of continuum manipulators [32], [33] also attracted a lot of attention in this field. Whether from the perspective of precise control or potential development value, it is an indispensable part to establish the kinematics and statics model of the designed continuum manipulator.…”