Design Of The Control System For A Laparoscopic Arm Of Minimally Invasive Surgical Robot

With the continuous development of robot technology and medical science,a wide range of surgical robots are being proposed and applied in the surgical operation.Robot-assisted surgery has the advantages of small trauma,high reliability and quick recovery after operation.However,at present,the manipulator arm and the laparoscopic arm system of the surgical robot are usually designed independently,which is time-consuming and laborious.For this purpose,this paper designs a universal and easy to perform control system for laparoscopic arm of minimally invasive surgical robot.According to the structure and functional requirements of the laparoscopic arm,the appropriate electrical components are selected for the joints.In order to realize good communication,the CAN bus is used in the system.The hardware control system based on the combination of PC and amplifiers is designed and the appropriate control hardware is selected.Moreover,a control cabinet of laparoscopic arm is built to make the experimental operation easy and protect the hardware.Based on the structural features of laparoscopic arm,this paper establish the kinematic coordinates on the theory of screws and develop the kinematics,inverse kinematics models.After building the mechanism model and kinematics model by SimMechanics and Simulink,this paper has verified the correctness of kinematics model by comparing the outputs and the errors between inputs and outputs.In order to make the laparoscopic arm move smoothly according to the expected trajectory,linear and circular interpolation trajectory planning are carried out in the Cartesian space for the movement of the end of the laparoscopic arm.And the fifth-degree polynomial interpolation trajectory planning are carried out in joint space for the joint motion.And we carried out the simulation experiment by Matlab software.In order to meet software control system functional requirements,firstly,we have used the CME 2 software to configure the drive and motor parameters for the realization of the servo system function and the follow-up program preparation;then we installed the CMO module,the CAN card driver and the data acquisition card's LabVIEW driver to build the development environment of the control system software.Finally,we have designed the human-computer interaction interface and realize the data acquisition function and joint motion control of the laparoscopic arm system in the LabVIEW development environment.Combined with the operation of the laparoscopic arm system requirements,we built and debugged the laparoscopic arm experimental platform.We measured the movement range of the passive joint and proved that the position of the arm is satisfied the requirements.And We measured the range of motion and forward and backward errors of before and after the compensation motion of the active joints.We draw the conclusion that the reverse error is the main source of error and motion error after compensation motion can meet the requirements.Through the Matlab software to compare the theoretical trajectory of the two motion methods,we verified The rationality of using PVT mode for multi-joint linkage control.And compared the actual end trajectory and the ideal end trajectory of multi-joint linkage control using PVT mode,we verified the feasibility of the software program and the accuracy of the end position control of the laparoscopic arm.The fixed-point-experimental results show that the fixed point of laparoscopic arm mechanism is real.