Design Of Rigid And Flexible Robot Based On Spiral Balloon And Fiber Bragg Grating Sensing

Natural orifice transluminal endoscopic surgery(NOTES)receives great popularity,which has the same benefit as traditional MIS,but has a small trauma,low invasiveness,shortened hospital time and desired cosmetic benefit.Currently,flexible surgical robot has achieved great success.However,subject to the natural cavity,it is still challenge to achieve high stability and combination of rigid and flexible characteristics of the robot,failing to fulfill requirements of multiple surgical operations.To meet the operation requirements of NOTES,driven by spiral balloon structure,based on shape memory polymer(SMP)backbone and helical configuration of optic fiber with multiple fiber Bragg grating(FBG)sensors,this paper explains the mechanism design,component and motion feature of the robot structure.Finally,a rigid and flexible robot prototype is fabricated and tested.Content of this paper is illustrated as follows:Firstly,center on needs of NOTES operations,we propose a bio-inspired structure made of spiral-woven silicone balloons,draws up the overall plan for the stiffness controllable flexible robot,also designs and analyzes its driving structure,SMP rigidflexible transfer backbone,and stiffness control system.The FBG sensing system is also designed.The integrative spiral structure effectively increases the flexibility and stability of the robot,thus reducing invasiveness and widening adaptability.The SMP backbone in glassy state provides a high stability for surgical operations,improving load capacity of the robot.The sensing system increases safety of the operation.Then,we present a practical FBG sensing system based on helical configuration of single optic fiber.The sensing principle and encapsulation method of FBG sensor are briefly described.Helical FBG sensing network is put forward,briefly introduced,elaborates in detail,and optimizes.The strain-curvature model is established,for analyzing the three-dimensional shape reconstruction of robot.It is theoretically proved that the differential temperature compensation model deduces the temperature effect on FBG sensor,demonstrating the feasibility of temperature elimination.Finally,following the overall plan,we fabricate a stiffness controllable robot prototype,mainly involving the design of its driving unit,analysis and selection of the hardware composition,and design of software components.Bending and torsion experiments of FBG sensors are conducted,thus demonstrating the feasibility of curvature and torsion sensing.SMP backbone experiments,different balloon inflating experiments and helical propulsion movement are performed and verified.Thus,demonstrating the feasibility of spiral-balloon structure and FBG sensing system.