Research On Master-slave Control For Multi-arm Thoracic And Abdominal Minimally Invasive Surgical Robot

With the development and integration of robotics and minimally invasive surgery,minimally invasive surgical robots have emerged to solve the problems of inconsistent hand-eye movements and easy fatigue of the surgeon in the traditional minimally invasive surgery.The most commonly used minimally invasive laparotomy robot is the master-slave remote operation mode,in which the surgeon sits in front of the console and the eye observes the operation in the abdominal cavity in real time through the screen in front of the console,while the foot and hand manipulate the foot pedal and master operator,respectively,to follow the movement of the surgical robot according to the observed situation.In this paper,a master-slave control system composed of master manipulator,robot platform and vision system is established according to the characteristics and surgical requirements of multi-arm laparoscopic minimally invasive surgery robot.In accordance with the basic requirements of the master-slave operation,the distributed hardware structure of upper and lower processors will be selected for the construction of the hardware system,and the software structure will be partitioned by function,and the program development GUI will be constructed.Then,the kinematic model of the master manipulator and the remote centre mechanism is established by analysing the structural parameters of the master manipulator and the remote centre mechanism by the DH parameter method.The inverse kinematics solution is obtained,and the workspace of the remote center mechanism is analysed by means of the kinematics model.It is verified that the robot workspace meets the working requirements of abdominal minimally invasive surgery.After the establishment of the kinematics model,the positioning error model based on the kinematics geometric parameters is established by differential transformation,and the distance error model based on the kinematics geometric parameters is further obtained.By calibrating the infrared binocular camera,the calibrated kinematic geometric parameters are obtained using the particle swarm optimization algorithm,and then the robot error is compensated in real time.After establishing the kinematic model,the master-slave control algorithm is designed,including the hand-eye coordination algorithm,proportional incremental control algorithm,multi-arm switching control and speed planning.The coordinated control of the master manipulator and the endoscopic instrument is established by hand-eye calibration and homogeneous transformation.Incremental control is used to realise the redirection function of the main manipulator during the operation,ensuring that the operator can always operate comfortably.Proportional control is used to realise the large scale adjustment movement of the instrument and the small scale movement of the lesion area.Aiming at the single-arm,double-arm,triple-arm and quadruple-arm surgical applications of the robot platform,the unique design of the hardware interface is combined with the program to realise the requirements of detection and switching control.Finally,the experiments of small ring accurate sleeve column and S-shaped path sleeve ring,suture experiment and electric knife cutting animal tissue in vitro verified the actual effect of hand-eye coordination,precise control ability after robot error compensation,smooth robot operation after speed planning,and flexibility and reliability of master-slave control.