| With the rapid development of robotics technology,more and more researches have been done on robot-assisted minimally invasive surgery.In order to increase the reliability of robot-assisted surgery,more and more researchers are engaged in robot-assisted surgery.This paper focuses on the robot structure itself,and carries out the corresponding structural innovation design and analysis and verification for the existing problems of some new minimally invasive surgical robot structures.The research contents include the following:(1)According to the operation process,working condition and environment of the minimally invasive operation of the abdominal cavity,the surgical requirements that need to be met are obtained,and the two-degree-of-freedom centering mechanism and the one-degree-of-freedom surgical instrument moving mechanism in the telecentric mechanism are respectively configured.A new type of remote translational actuation mechanism has been innovatively designed to reduce the impact on end surgical instruments.Subsequently,the driving torque of the mechanism is estimated.Finally,the ANSYS simulation software is used to analyze the static force of the most important members of the mechanism.(2)Through the design requirements of surgical instruments,the design of the surgical instrument drive box is designed,and the rope drive mode is selected.It is innovative to propose linear drive using rectangular rods,and calculate the linear drive distance according to the range of motion of the end surgical tool..The motion coupling of the existing surgical tools is analyzed,and the decoupling mechanism is designed by using the characteristics of the planetary gear train,and the dimensional relationship of the mechanism is determined.Subsequently,the overall layout of the rope drive was designed.Finally,the rotational torque required by each of the end surgical tools is estimated to provide a basis for motor selection.(3)The designed telecentric mechanism and surgical instruments were analyzed by positive kinematics.The exponential product formula is used to solve the forward kinematics of the mechanism,and the positive kinematics relationship matrix obtained by the solution is used to obtain the random end value of each driving angle by Monte Carlo method to obtain the corresponding end position vector,thereby obtaining the motion working space of the entire mechanism.(4)In order to verify the kinematics accuracy of the designed mechanism,the gap error model of the mechanism is established by the principle of virtual work,and the rod length error model of the mechanism is established by the loop increment method.In solving the gap error model,the mechanism of joint constraint and force couple is solved by the theory of spin quantity.Subsequently,the sensitivity coefficients of each error source are established,and the error distribution curve and sensitivity histogram are obtained by using Matlab.Finally,an error model is established for the axial winding of the rotation degree of the surgical tool,and the relationship between each parameter and the output error is obtained,and the appropriate parameters are determined. |
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