| Minimally invasive surgical robot overcomes the shortcomings of traditional minimally invasive surgery in observation,amenity,operation and flexibility,and has been widely used in assisting doctors to perform surgical operations.However,existing minimally invasive surgical robots still lack a force feedback function,which is unable to tell the doctor about the contact force between the surgical instrument and the patient’s tissue.Doctors cannot use tissue touch to identify tissue properties or lesions,and it becomes difficult for doctors to apply precise forces when performing delicate operations.At present,there are still some problems in the research on the robot human detection of minimally invasive surgery,such as insufficient measurement dimension,low range and accuracy,and poor compatibility with instruments,which limit the further improvement of the quality and efficiency of robot-assisted minimally invasive surgery.This thesis carried out corresponding research on the design criteria of mechanical manpower detection in minimally invasive surgery,designed six-dimensional micro force/torque sensors and force-sensing surgical instruments,and carried out static calibration of force sensing units and performance testing experiments of surgical instruments,to verify the feasibility and effectiveness of the developed key technologies of force-sensing surgical instruments.The main work of this thesis is as follows:The interaction force between surgical instruments and tissues and organs was analyzed.The overall requirements of minimally invasive surgical robots and the kinematic and dynamic characteristics of the wrist of surgical instruments were summarized,the forces on different parts of the surgical instruments were analyzed,and the force detection dimension and the positioning of the force detection unit were defined in the execution of typical technical operations.The range of the interaction force and the detection principle of the optical fiber force sensor are summarized to provide design requirements for the micro sensor.A set of six-dimensional micro force/torque sensor is designed.A Stewart platform with elastic hinges was designed to detect the six-dimensional force/moment component of the interacting force.A parameter optimization method considering the homogeneity of the generalized force and sensitivity is proposed to optimize the geometric parameters of the Stewart platform structure with multiple objectives in order to best adapt to the given external load.The optical measurement system of the sensor was constructed by using fiber Bragg grating detection method and optical sensing demodulation instrument,and the prototype of the sixdimensional micro force/torque component sensor was designed and assembled.A new type of six-dimensional force-sensing surgical instrument was developed.The coupling between the clamping force and the external force/moment is removed by the decoupling pulley in the clamping force detection unit.Two degrees of freedom wrist mechanism,one degree of freedom clamp mechanism and instrument shaft assembly were designed to provide four degrees of freedom motion of yaw,pitch,opening and closing,and roll for surgical instruments.Design the transmission,drive and interface units of surgical instruments,complete the design and assembly of the system assembly and principle prototype of the new force-sensing surgical instruments.Complete static calibration experiment and motion performance test of surgical instruments.A special static calibration platform was designed and the linear relationship between the output sensing unit and the wavelength variation of optical fiber was found by means of weight loading.The static calibration matrix was solved based on the least square method and the measurement range and accuracy of the force sensing unit were calculated.The motion performance of surgical instruments was tested by wrist trajectory tracking experiment and master-slave teleoperation experiment. |
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