Development Of The Celiac Minimally Invasive Surgery Robotic Executing System And Research On Its Control Algorithm

Robot minimally invasive surgery not only has the strengths of traditionalminimally invasive surgery: Small wound, less pain, less bleeding and rapidpostoperative recovery, but also solves many problems existing in traditional minimallyinvasive surgery, such as master-slave control surgery can reduce the doctor’s fatigueand resolve the problems of "chopstick effect" in traditional minimally invasive surge ry;the robot can also achieve subtler surgical operation which can greatly expand thedoctor’s surgical capacity. It is because of these unparalleled advantages, that roboticminimally invasive surgery has been widely recognized in the field of surgery, a ndmany domestic and foreign medical institutions both showed great desire to use theminimally invasive surgical robot. Researching and developing a minimally invasivesurgical robotic system with independent intellectual property not only has highacademic value, but also can bring enormous social and economic benefits, which is thepurpose and significance of the research work presented in this thsis.By analyzing the operating environment of minimally invasive surgery, the paperpresented the basic requirements of the minimally invasive surgical robot mechanismdesign, and developed a surgical robot execution system consisting of surgicalmanipulator system and micro-instruments. In order to meet the intraoperative spatiallyinvariant point required by the minimally invasive surgery, a new romote-center-of-motion(RCM) mechanism, parallelogram RCM mechanism, was designed by improvingcomposite parallelogram mechanism. In addition, a wire-driven modular joint withsingle-degree-of-freedom was also developed, which has been used for the wristmechanism design of the micro-instruments. The motion test of micro-instruments wristshows that the joint has good flexibility and can fully meet the design requirements ofthe micro-instruments wrist mechanism.In order to meet the dexterity requirements of robotic manipulator in minimallyinvasive surgery, the paper constructed comprehensive evaluation index of the dexterityby using the jacobian matrix singular value, and established the optimization modelbased on the index. By using sequential quadratic programming algorithm, theoptimization problem was solved and the optimization results show that the manipulatorhas a good isotropy and operability in its work space, which can meet the requirementsof dexterity for the minimally invasive surgery. In addition, the paper improved thegradient projection algorithm by using the closed inverse solution equation of thepositioning mechanism, and achieved the preoperative positioning planning of the twoinstruments manipulators based on the improved gradient projection algorithm. The performance of the preoperative planning in the animal experiments showed that theplanning method has a good guidance for preoperative positioning of the robot system.For the minimally invasive surgery robot systems developed in this paper, amaster-slave control algorithm based on the separation of the position and posture waspresented. By separating position and posture of the master-slave kinematic mapping,the control algorithm simplified the6-DOF serial mechanism inverse kinematicsproblem into two3-DOF serial mechanism inverse kinematics problem, which cangreatly reduce the difficulty of the inverse kinematics solving problem of the system. Inaddition, trajectory tracking control algorithm based on the position increment of themaster hands was realized by using the control algorithm, which successfully solved themotion consistency problem, remapping problem and the position instruction smoothingprocessing problems. Moreover, a wrist posture partitioning algorithm was presentedbased on the position of the instrument tip unchanged, and the algorithm can achieve thefast and safe replacement of the micro-instruments during minimally invasive surgery.On the basis of the above researchments, the minimally invasive surgical roboticsystem developed in the paper was integrated.The calibration and test results of theparallelogram RCM mechanism showed that the mechanism was able to meet theminimally invasive surgery requirements for the stability of the remote center position.The master-slave control algorithm was verified by using actual data obtained in theoperation, the results indicated that the proposed master-slave control algorithmsatisfied the requirements of the master-slave trajectory tracking. At last, the wholeoperation performance of minimally invasive surgical robot system was verified by theactual animal gallbladder removal experiment, and the operation effect suggested thatthe robot system has a good operation performance and it has the basic ability to clinicaloperation.