Design, Measurement and Shape Reconstruction of Soft Surgical Actuator Based on Fiber Bragg Gratings

Abstract

Soft actuators are the components responsible for organs and tissues adsorptive fixation in some surgical operations, but the lack of shape sensing and monitoring of a soft actuator greatly limits their application potential. Consequently, this paper proposes a real-time 3D shape reconstruction method of soft surgical actuator which has an embedded optical fiber with two Fiber Bragg Grating (FBG) sensors. First, the design principle and the sensing of the soft actuator based on FBG sensors are analyzed, and the fabrication process of soft actuator which has an embedded optical fiber with two FBG sensors is described. Next, the calibration of the FBG sensors is conducted. Based on curvatures and curve fitting functions, the strategy of 3D shapes reconstruction of the soft actuator is presented. Finally, some bending experiments of the soft actuator are carried out, and the 3D shapes of the soft actuator at different bending states are reconstructed. This well reconstructed 3D shape of a soft actuator demonstrates the effectiveness of the shape reconstruction method that is proposed in this paper, as well as the potential and increased applications of these structures for real soft surgical actuators.

A Contact Force Sensor Based on S-Shaped Beams and Optoelectronic Sensors for Flexible Manipulators for Minimally Invasive Surgery (MIS)

“…Recently, state-of-the-art flexible manipulators [23][24][25][26][27][28] have integrated various sensing modalities such as shape and stretch sensing units, tactile sensing units and multi-axis force/torque sensors. For example, the continuum manipulators are integrated with light intensity modulation based fibre optic sensors to measure force/torque [19,23] as well as the manipulators' shape [29] based on stretch sensing elements [49].…”

“…However, it is typically difficult to miniaturise the overall size of the manipulator due to the space needed to house the optical fibres. The Fibre Bragg Grating (FBG) sensing elements are widely used to measure contact forces and the shape of the flexible manipulators [25][26][27]. This element helps to cut down the size of the manipulator without the loss of outstanding sensing modalities.…”

“…This structure can measure contact force components in every segment and estimate arbitrary shapes using orientation information. Conventional shape sensing methods employing fibre optic and FBG assume constant curvature model [25][26][27] whereas our approach does not need such an assumption since an arbitrary shape can be estimated by composition of a series of relative orientation matrices. Consequently, this may achieve precise closed-loop motion control as well as acquisition of accurate contact force information [31][32][33].…”

Optical Fiber Sensor Performance Evaluation in Soft Polyimide Film with Different Thickness Ratios

“…According to a previously determined model [25,28,29], the FBG sensor is located deviation from the central axis, as presented in the dashed line E–F in Figure 2b. h 1 represents the range from the FBG sensor to the outer arc of polyimide film, and h 2 represents the range from the FBG sensor to the inner arc of the polyimide film.…”

Special Issue on Precision Dimensional Measurements

“…It has the capability for absolute positioning based on a vernier-type structure. He et al propose a real-time 3D shape reconstruction method of soft surgical actuator which has an embedded optical fiber with two Fiber Bragg Grating (FBG) sensors [19].…”