Research On Human-robot Cooperative Control Of Joint Replacement Robot

As more and more medical robots come into clinical applications,orthopedic surgery assisted robots have attracted more and more attention.Orthopedic surgery is more suitable for introducing robots into the surgery because of the physical properties of rigid bones.In recent years,orthopedic surgical robots have also become the most approved medical robot category by the FDA(US Food and Drug Administration).Joint replacement surgery is an important field in orthopedic surgery.The purpose of this surgery is to completely or partially remove the joint bone tissue of the patient and replace the artificial joint to restore the function of the affected limb.Compared with traditional artificial surgery,robot-assisted joint replacement surgery can improve the success rate of surgery,but there are currently no mature joint replacement robot products in China.The main content of this thesis is the human-robot cooperative control method in joint replacement surgery.Aiming at the man-machine cooperation task in joint replacement surgery,a tendon-driven tandem six-joint robot is designed and developed,and two variable admittance collaborative control methods are proposed to improve the operator's ability of boundary control of the robot in man-machine collaboration.Experiments and simulations are performed on the above methods.The specific work is summarized as follows:The working characteristics of human-robot collaboration in joint replacement surgery are analyzed,a rope transmission scheme is selected for the robot,the configuration of the robot is determined,and the parameters of the transmission components are analyzed and calculated.Completion of forward and inverse calculation of joint replacement robot,calculation of Jacobian matrix,singularity analysis,analysis of workspace,dynamic simulation.The prototype integration was completed,the basic control code was written,and the basic interactive experiments were implemented on the robot platform to verify the basic functions of the joint replacement robot system.A variable admittance control method based on dynamic reference points for joint replacement surgery is proposed.This method does not change the damping and mass parameters under admittance control,and instead chooses a dynamic reference point,and the virtual spring on the reference point improves the operator's boundary control ability when dragging the robot.Further interactive experiments were performed on the small robot platform.Ten experimenters were randomly selected to operate the small robot to complete the interactive experiment.The results show that this method can improve the operator's boundary control ability.A variable admittance control method based on human hand motion prediction is proposed.NDI vision tracking equipment is used to collect hand movement information,and after processing the data to a certain extent,long short term memory neural networks are used to learn and predict human movements.Through the prediction information,the admittance damping is changed,so that the damping of the admittance controller in the direction perpendicular to the prediction direction becomes a certain multiple,thereby giving the robot the constraint of flexibility and moving in the prediction direction.Thereby,the compliance of the robot to the desired motion trajectory of the robot is improved.The validity of the method is verified by simulation.