| The traditional percutaneous needle insertion surgery is difficult and time-consuming,and it depends on the experience and technology of doctors excessively.In order to reduce the time and difficulty of the surgery and the influence of human factors,it is of great clinical value to study the key technologies of the percutaneous needle insertion surgery robot guided by three-dimensional ultrasound system.According to the needs of doctors,this paper designs two operation modes for the ultrasonic scanning robotic arm: master-slave operation mode and human-robot cooperation drag mode.Doctors can choose a reasonable and comfortable mode to operate according to their habits and operation occasions.Based on the above two operation modes,this paper mainly studies two corresponding control technologies,that is,the master-slave control technology and the human-machine cooperative drag control technology.First,based on Ether CAT bus technology and Twin CAT motion control system,the real-time control system of ultrasonic scanning robotic arm is constructed.The hardware adopts the distributed structure,and the real-time communication between Beckhoff Industrial Control Computer and each joint module is realized by Ether CAT bus.At the same time,the hierarchical structure of the software system is designed.The functional module is designed between different levels and within each level to optimize the software system structure.Second,by analyzing the structure of the ultrasonic scanning robotic arm,the analytical solution of forward and inverse kinematics is obtained.Combined with the analysis of differential kinematics,the geometric Jacobian matrix describing the linear mapping between joint velocity and terminal generalized velocity is solved.For the case that the poster of robotic arm is represented by Euler angles,the solution method of analytical Jacobian matrix is obtained and the relationship between the two Jacobian matrices is given.At the same time,the statics of the ultrasonic scanning robotic arm is analyzed by the duality of kinematics and statics.This part provides the mathematical basis for the following control theory.Third,for the master-slave operation mode,a master-slave control system and algorithm are developed.The master hand collects the motion information of doctor's hand and then transmits it to the control system,which maps the information to the slave hand to perform the motion.The real-time algorithm of master-slave control is designed by using the master-slave mapping strategy based on differential motion increment and inverse Jacobian matrix,and the error feedback link is introduced to compensate the accumulated errors.In addition,a master-hand shake filtering algorithm and a master-slave control human-computer interaction interface are also designed.The master-slave control experiment is completed by using the ultrasonic scanning robotic arm experiment platform,Omega.7 master hand and Bechoff industrial computer.Finally,for the human-machine cooperative drag mode,a variable parameter admittance control system based on fuzzy inference system is designed.The input of the system is the doctor's interaction force signal collected by the sensor,and the output is the end velocity of the robotic arm which is mapped to the desired joint velocity by the inverse Jacobian matrix,then the drag function is realized by using the joint velocity controller.At the same time,based on the estimation of the operator's control intention,a fuzzy inference system is designed to realize the online adjustment of virtual damping parameters.In addition,the gravity compensation algorithm of the input force signal of the control system is deduced,and the simulation verification of the drag control algorithm is completed by using the robot simulation software Coppliasim and MATLB for programming. |
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