The Design Method And Experimental Research Of Ultrasonic Scalpel For Surgical Robot

As an energetic surgical instrument with both cutting and hemostatic functions,ultrasonic scalpel has many advantages such as high cutting accuracy,reliable vessel closure,small thermal damage and good safety,which can well meet the high requirements of traditional minimally invasive surgery(MIS)for cutting and hemostatic instruments.With the further research and promotion of MIS robots,robotassisted minimally invasive surgery has replaced the traditional MIS.However,no mature ultrasonic scalpel can be applied in MIS robots,so based on the existing ultrasonic scalpel research theory,this paper designed an ultrasonic scalpel for surgical robots.On the other hand,it is difficult for the existing ultrasonic scalpel to seal large blood vessels with diameter more than 3mm.In order to solve this problem,this paper puts forward a design scheme of ultrasonic scalpel with enhanced hemostasis.Focusing on these two themes,the following work is carried out in this paper:Firstly,the main factors influencing the cutting,hemostasis and vibration of ultrasonic scalpel for surgical robot were summarized,and the performance indexes suitable to the requirements were put forward.Based on the theory of electromechanical equivalent circuit,the equivalent circuit model of the transducer was constructed,and the necessary dimensions of the transducer were calculated.Based on the theory of ultrasonic wave and finite element method,this paper designs and analyzes the arbor,puts forward a new arbor structure,and simulates the fatigue life of the arbor.Then,a prototype ultrasonic scalpel for surgical robot was made,and its impedance and amplitude characteristics were measured.In vitro tissue cutting and vessel closure experiments were carried out with an ultrasonic scalpel prototype,and the good cutting and hemostatic performance of ultrasonic scalpel was verified.Finally,the whole structure of ultrasonic instrument for surgical robot was designed.Secondly,to solve the problem of insufficient ability of existing ultrasonic scalpel to seal large vessels,a new ultrasonic scalpel based on longitudinal torsional vibration was proposed.The parameters of the enhanced hemostasis type ultrasonic scalpel were analyzed and optimized to obtain the optimal structure size,and the vibration characteristics of the traditional longitudinal ultrasonic scalpel and the enhanced hemostasis type ultrasonic scalpel were simulated and compared.Finally,the prototype of the traditional longitudinal ultrasonic scalpel and the enhanced hemostasis type ultrasonic scalpel were manufactured to carry out the hemostatic performance comparison experiment on the premise of ensuring the same experimental conditions.Through temperature characteristic experiment and thermodynamic simulation,it is proved that the enhanced hemostasis type ultrasonic scalpel in this paper can achieve the same hemostatic effect under the premise of less thermal damage to tissues.