Research On Multi-arm Cooperative Strategy Of Minimally Invasive Surgical Robot In Suture And Knot Operation

In recent years,as minimally invasive surgery is becoming more and more popular among doctors,the adjuvant medical surgery robot,which can improve the flexibility and precision of doctors' operation,is increasingly accepted by doctors and appears in various surgical fields.Compared with rigid surgical instruments,flexible surgical instruments,which can not only meet the requirements of doctors' degrees of freedom but also accurately achieve the target posture in a small space,have gradually come into the field of vision of doctors.Based on the kinematics control of the robot system,this paper studies the cooperative strategy of each robot arm in the operation of minimally invasive surgery suture and knot.According to the structural characteristics of discrete flexible surgical instruments,the motion law of each discrete joint was analyzed,and the spatial motion relationship of each flexible body was obtained.The relationship between the driving line length of each joint and the posture of the end-effector was obtained by using space geometry and projection method,and the forward kinematics equation of the flexible surgical instrument was obtained.By analyzing the characteristics of the forward kinematics equation,the matrix operations is used to obtain the equations with parameters,Newton iteration method is used and the initial point of iteration is selected to solve the equations skillfully to obtain the solution of the inverse kinematics equation.Monte Carlo method is used to solve the workspace of surgical instruments.The changes of motion and terminal posture of each joint of the surgical instrument during minimally invasive surgery were analyzed,and the task cooperative allocation criteria based on non-cross collision and wrist deflection Angle of the surgical instrument were proposed.In the case of fixed incision position,the task division of surgical instruments at each incision can be carried out according to this criterion and combined with the kinematics analysis of surgical instruments,which is conducive to the division of suture operation on the premise of satisfying the safety.To analyze the position of each surgical instrument and coordinate the operation relationship during the knotting operation of minimally invasive surgery,and to allocate the task of each surgical instrument at each incision,so as to optimize the suture operation.The forward and inverse kinematics equations are verified.Given the initial length of the wire rope,the position of the end of the surgical instrument was obtained by using the relationship of pure geometric angles and the proposed kinematics equation.The two positions were the same.By simulating master-slave control mode to verify the flexible surgical instruments inverse kinematics equation,and calculate the program run faster,the simulation results show that the Win10 system operation,4 GB of memory,Inteli5-3470 processor(3.20 GHz)under the electronic computer required to complete a kinematics time less than 3 ms,equation error is less than 0.0001 mm,proved that the inverse kinematics equation method described in this article the right;The movement experiment of flexible surgical instruments was designed to verify the actual operation of surgical instruments and analyze the causes of errors.The simulation of the operation process of suture and knotting and the simulated task assignment of the surgical instruments at the selected incision proved the suitability and safety of the task assignment.