6-DOF Minimally Invasive Surgery Master Manipulator Design And Resistance Compensation Control

Minimally invasive surgery has become the mainstream surgical method at this stage due to its short recovery period and small wound.However,traditional minimally invasive surgery also has problems such as uncoordinated hands and eyes,poor flexibility,and long-term operation fatigue.The medical assistance system of master-slave remote operation has improved these problems.The master manipulator,as an instrument that directly interacts with the doctor,directly affects the safety and comfort of the operation.Therefore,this article focuses on the master manipulator.First of all,this article designs the master manipulator based on the principle of simplifying control and improving comfort.Based on the master manipulator’s requirements for operating comfort and high spatial flexibility,it is determined that the master manipulator configuration is selected as the tandem type,and the different joint configurations are finally determined to be the first two The joint axis is selected as the vertical direction to reduce the number of gravitational moments that need to be compensated,and the pressure of gravity compensation is relieved by adding counterweights to the structure.The master manipulator is divided into three parts: arm,wrist,and posture,and designed separately.The modular joint adopts wire drive transmission mode,which satisfies the principle of low moment of inertia and lightweight design of the master manipulator joint,and is designed with preload.The pre-tightening of the wire rope is completed by the reel,and the final processing and assembly complete the construction of the master manipulator platform.The parameter model of the master manipulator is established by using the improved DH modeling method.Based on the model,the transfer relationship between the various members of the master manipulator is established,so as to derive the master manipulator ’s forward and inverse kinematics equations and dynamic equations,and obtain the joint motion information and The relationship between joint driving forces and the obtained inverse dynamic equation are linearized,combined with the linear friction model to construct the observation matrix,combined with the least square method to complete the identification of the main hand dynamics and friction.The passive movement of the active hand will produce additional force on the human hand.This resistance will cause the doctor to fatigue under the condition of long-term operation.To solve this problem,a resistance compensation control is proposed.Based on the identification result,the active hand movement time is calculated.The generated resistance information is compensated by the drive motor.Finally,an experimental platform for the master manipulator compensation control is built,and the force generated by the master manipulator on the human hand under the two conditions of opening and closing the compensation control is collected,and the comparative analysis draws a conclusion that the compensation control effectively compensates for the resistance.