Research On Design Method Of Six-dimensional Force/Torque Sensor For Endoscope Surgical Robot

Compared with traditional endoscopic surgery,endoscopic surgery robot has significantly improved in observation,operation,comfort,flexibility and accuracy.However,there is still no force feedback function in endoscopic surgical instruments,which makes it impossible to accurately measure the interaction force between surgical instruments and human tissues during surgery.Doctors cannot accurately obtain force feedback information when performing some delicate operations,so the lack of force feedback has become a major limitation in the development of endoscopic surgical robots.In order to overcome the limitation of force feedback of endoscopic surgery robot and solve the problems in measurement dimension,measurement range and sensitivity of relevant research work at home and abroad,this thesis designed a six-dimensional miniature force/moment sensor for typical technical operation of endoscopic surgery.The technical operation needed for laparoscopic surgery was analyzed to clarify the requirements of force detection technology in technical operation.According to the relevant data provided by clinicians,the detection position,measurement range and measurement accuracy of interaction force between surgical instruments and patient tissues and the detection principle of optical fiber sensor were studied,and the design requirements of micro-six-dimensional force/torque sensor were formulated.Stewart platform is selected as the elastic structure of the six-dimensional miniature force/moment sensor,and the characteristic matrix of the structure is studied,that is,the relationship between the six-dimensional applied load and the axial forces of the six connecting rods of Stewart platform.The isotropy of Stewart platform is analyzed,and the mathematical expressions of the isotropy of force,moment and sensitivity are obtained.The dimension parameters of Stewart platform structure were determined according to the clinical requirements of endoscopic surgery,and multi-objective optimization of sensor Angle parameters was carried out by non-dominated genetic algorithm to obtain the optimal structural design parameters.Then according to the optimization algorithm to get the design parameters of the Stewart platform elastomer force/torque sensor is designed,considering the stiffness and sensitivity sensor requirements,choose in during the design of the elastomer elastic hinge hinge instead of a ball,open to the outside connecting rod choose C type,and excavated to facilitate pasting fiber on the back of the connecting rod,The three-dimensional model of the elastic body is established and the finite element analysis is carried out.The gap between the theoretical value and the finite element analysis value is analyzed,so as to determine the force of the elastic body and establish the sensor prototype.Finally,the sensor calibration device,calibration method and calibration matrix were studied,and the special calibration platform was processed to simulate the force by adding or reducing the weight.Determined by temperature compensation fiber experimental temperature compensation coefficient,load fiber paste in the groove on the reverse of the connecting rod,feel the strain of elastomer cause changes in the wavelength of light signal,using the optical wavelength demodulation devices will light signals and force signals through calibration matrix,linear static decoupling calculation method based on least square method,get the calibration matrix,Realize the measurement of six-dimensional external load.