Characteristics of cable pulley system for interventional surgical robot
                                                            YIN Jie, QI Fei, JU Feng, CHEN Bai
          （College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China）


Abstract: Aiming at the problem of nonlinear friction in the movement of the interventional surgical robot， the transmission characteristics of the cable pulley system were investigated. The classical Capstan equation was used for analysis of the force of the cable in the transmission process. After the analysis of the relationship between friction and wrapping angle， the relationships between friction and material contact characteristics were also established by power law. Then， the input force and output force of the cable in the transmission process were measured by the tension sensor， and the friction of the cable system was tested by changing the wrapping angle. Finally， the accuracy of the transmission model was analyzed. The results indicate that the friction of the pulley cable system is related to the contact characteristics of the material and wrapping angle. When usin g the polymer material as the driving cable and considering viscoelastic deformation， the frictional force of the rope is small and the system transmission efficiency can reach 90%， which ensures the precision of the force control.
Key words: interventional surgical robot; force control; cable pulley system