| Minimally Invasive Surgery(MIS)with small wound,less pain,rapid recovery,less postoperative complications and shorter hospitalization time,is widely used in the world.However,the traditional minimally invasive surgery causes some difficulties for doctor,such as rotational motion around the fixed point causes the hand-eye uncoordination problem,the flexibility of surgical instrument is low,long-term surgical operation which is achieved by holding surgical instrument causes the doctor fatigue,the fine operation is hard to be complished for hands tremor.Robot-assisted MIS can greatly resolve these problems mentioned aboved,improve the operation environment and the quality of surgery.Therefore the study on the slave mechanism and control of the celiac MIS system is carred on in this paper.Mechanism synthesis of RCM mechanism of celiac MIS robot is studied.A novel uncoupled and isotropic 2-Do F parallel mechanism(PM)of MIS robot is presented in this paper,forward and inverse kinematic models are established based on screws theory,fully uncoupled,isotropic characteristic,singularity,compactness,and worksapce of the PM are analyzed.A serial RCM mechanism with modular design of MIS robot is presented.The serial RCM mechanism kinematics is established,the relationships between the parameters of the RCM mechanism and the mechanism performances of the serial RCM mechanism are bulit,the four indexes: the improved global kinematics indice,the mechanism compact performance indice,the improved global comprehensive stiffness performance indice and the improved global dynamics indice are chosen as the optimizational objective functions,workspace,mechanism parameters and mass are regarded as the comstraint conditions,the multi-objectives optimization is accomplished by NSGA-?algorithm.Lastly,by comprehensive comparison of two RCM mechansims,the serial RCM mechansim is chosen to design MIS robot prototype.The mechanical body of the Celiac MIS robot is studied.In order to improve the stiffness of the serial RCM mechanism,reduce the collision pro bability and provide guidance for the concrete structure design,the mechansim parameters of the serial RCM mcchanism and the structure parameters of the links are chosen as the optimized parameters,the global kinematics performance index and the global comprehensive stiffness performance index are regarded as the optimized goals,the mutli-objective optimization is accomplished by the NSGA-?.Based on the optimized results,the prototype of MIS robot is desiged.The prototype design of MIS robot consists of the passive arm design,RCM mechanism design and surgical instrument design.One mechanical decoupling method called three section platform design is proposd to remove the coupling motion between the linear platform and the interface of surgical instrment in the process of the RCM mechanism.Another mechanical decoupling method called hollow line design is proposd to remove the coupling motion between wrist and the forceps in the process of the surgical instrment.Two kinds of mechanical decoupling method are put forward to improve the independence of the motor and reduce the complexity of the control algorithm.Finally,the safe design of MIS robot is achieved.Nolinear PID joint control of the Celiac MIS robot is studied.D ynamics model of the MIS robot is established by Lagrange method and is validated by Matlab simulation.In order to improve the control stability and accuracy of the Joint,two joint nonlinear PID control laws with new saturated function of the celiac MIS robot are put forward,global asymptotically stable conditions of the two Nonlinear PID laws are proved.The integral of the absolute position error and integral of the absolute input control error are chosen as the optimization functions,the global asymptotic stability conditions and the rated output torque of each motor are regardes as constraint conditions.Optimization results showed that position error of Nonliear PID control law which has new saturated function is less than the one which has the traditional saturated function.Robustness testing for model uncertainties,disturbance rejection and noise suppression is investigated.The PID control law with best robustness is validated by experiment.Master-slave control of the celiac MIS robot system is studied.Forward and inverse kinematic models of manipulators holding surgical instrument and endscopic are established based on the screw theory and validated by simulation.The Master-slave control algorithm is deduced based on kinematics model,which consisits of motion consistency control,the relative position control and the proportional control.The motion control algorithm of manipulator holding endscopic based on endscopic and the motion control algorithm of manipulator holding surgical instrument based on endscopic are derivated in the moiton consistency control.Two moiton control alogrithms are validated by the Simulink and SimMechanic simulation of Matlab.In order to accomplish Minimally Invasive Surgery,three auxiliary functions which are master-slave posture registration function,safety replacement function of surgical instrument and the Master-salve remapping function are achieved.Intergration and experiments of the Celiac MIS robot system are studied.Based on the integration of the Celiac MIS robot,the position change of the RCM point,absolute position accuracy and repetitive positioning accuracy of the MIS robot are tested,experiment results validate the effectiveness of the MIS robot design.The deoupled performance experiments are achieved,experiment results validate the effectiveness of the two mechanical decoupled methods.The experiment of Nonlinear PID is done,expeirment results validate the effectiveness of the Nonliear PID control law.Trajactory tracking,lantern ring,and wear line experiments are complished,experiment results verify effectiveness of master-slave mapping control alogrithm.Pig gallbladder and pig kidney removal experiments verify the effectiveness of the overall MIS robot system. |
PDF Full Text Request