Three-dimensional nonlinear force-sensing method based on double microgrippers with E-type vertical elastomer for minimally invasive robotic surgery

Abstract

SUMMARYThis paper presents a new type of forceps that consist of two microgrippers with the capability of direct force sensing, which enables grasping and manipulating forces at the tip of surgical instrument for minimally invasive robotic surgery. For the prototype design of the forceps, a double E-type vertical elastomer with four strain beams is presented, whose force-sensing principle is expounded. Thus, the forceps with the elastomer can be considered a compliant component, which provides tiny displacements that allow large strain, and the overall diameter is 10 mm. The sizes of the elastomer and forceps are successively determined by analyzing the relationship of several parameters and strain. Then, the linearity analysis of strain beams determines the positions to apply gauges for sensing. The two-dimensional force decoupling models for a single microgripper are proposed based on piecewise analytical polynomials of the strain difference and employed to develop a new three-dimensional force nonlinear decoupling algorithm based on double microgrippers, which realizes single-axial grasping and three-axial pulling forces. Finally, the required force-sensing performance of the proposed method is successfully verified in theory using finite-element simulations.

Surgical Microgrippers: A Survey and Analysis

“…Yu et al [104] presented a multi-DOF surgical type of forceps with an overall diameter of 10 mm, an overall length approximately of 27 mm, and a width of 8 mm for MIS. The authors focused their work on force feedback in order to reduce the risk of damage to the tissues due to the uncontrollable force magnitude.…”

Progress in Probe-Based Sensing Techniques for In Vivo Diagnosis

“…Hou et al developed a biocompatible piezoresistive triaxial force sensor chip, which was integrated into the grip of a continuum robot to sense the grasping force of the MIS [ 49 ]. Yu et al presented surgical forceps that consisted of double grippers with 3D pulling and grasp force sensing, and a simple structure with a double E-type strain beam was used as the substrate to minimize the size of the robot [ 50 , 51 ]. The main principle of these force sensing devices was to transform the voltage changes in the strain gauges into the force with a mathematical model.…”

Piezoresistive Elastomer-Based Composite Strain Sensors and Their Applications

“…[152][153][154] Robotic systems based on elastomers find application in robotic surgery for example in the form of forceps with microgrippers and embedded sensors for minimally invasive robotic surgery. 155 Artificial skin finds application also in the field of soft robotics such as for example a robotic arm with embedded elastomer sensors such as those based on PDMS for detecting the curvature during flexing and relaxing the robotic arm. 156 A conductive elastomer sensor was used by Yang et al for position sensing in a robotic gripper and could provide feedback that would regulate the pressure of the actuator.…”