| With the development of minimally invasive surgery,robot assisted percutaneous surgery plays an indispensable role in surgery.Robot-assisted percutaneous surgery is an important surgery that plays a vital role in minimally invasive surgery as well as in fields of applications such as biopsy,liver and kidney puncture,brachytherapy.This paper mainly focus on temperature compensation of fiber optic force sensor and the impedance control based on the force sensor information.The main contributions of this paper are as follows:(1)The method of temperature compensation is based on optical fiber force sensor.The fiber optic force sensor is integrated at the tip of puncture needle,and the temperature changes greatly when the needle tip punctures into the tissue.In order to obtain accurate force of needle tip,it is significant to eliminate the effect of temperature on fiber optic force sensor.Therefore,we establish compensation mathematical model by collecting temperature-signal experimental data to overcome the impact of temperature during the puncture course.(2)The impedance control is feasible for the robot-assisted percutaneous.The main challenge is that the organs punctured by the robot needle are generally non-uniform elastic tissue,which is prone to shift and nonlinear deformation under the action of force.Moreover,the needle cross layered discontinuous tissue for percutaneous puncture of soft tissue,their mechanical properties and boundary conditions are different.Therefore,an impedance control strategy for puncture robot is proposed,which based on experimental data to identify the impedance control model parameter of puncture and achieve controlling the interaction between the needle and soft tissue by adjusting the speed.(3)The robot needle puncture experiment operates on soft tissue.The robot needle control experiments were test on pig liver,pork tissue to verify the algorithm performance by changing the impedance control.We observed the stability and adaptability of the control system by changing impedance control parameters.In this paper,a new type of optical fiber sensor is used to measure the puncture force of needle in real time,then feedback the information to the impedance controller to realize the position and force control.The experimental results on biological tissue samples show that the proposed algorithm can effectively reduce the puncture force and improve the safety of puncture. |
