机器人辅助微创手术器械丝传动张力传递研究

Study on the Tension Transmission of Steel Cable-driven Surgical Instrument for Robot-assisted Minimally Invasive

机器人辅助微创手术器械一般采用丝传动来实现手术器械大长径比结构下的动力传递,传力过程中钢丝绳的张力传递损失会引起手术器械关节运动误差,因此研究丝传动张力变化是保证手术器械运动精度的前提。根据手术器械结构特点,引入导轮与钢丝绳的半径比及张力倾斜角来表征钢丝绳弯曲刚度,通过对钢丝绳与导轮接触区域与非接触区域的受力分析,得到了钢丝绳的张力比计算公式。试验结果表明,应用所提出的张力比计算公式获得的张力值与传感器直接测得的张力值比较吻合。此外,应用张力比计算公式分析了包角、摩擦因数、半径比、张力倾斜角等结构参数对钢丝绳张力变化的影响。该研究工作可为手术器械的精确运动控制及结构设计提供理论指导。

The surgical instruments for robot-assisted minimally invasive surgery generally use steel cable-driven to achieve the power transmission under the structure of large length diameter ratio.The tension loss of steel cable in the process of force transmission will cause motion error of surgical instruments.Therefore,the research on the tension change of steel cable is the premise to ensure the motion accuracy of surgical instruments.According to the structural characteristics of surgical instruments,the radius ratio of pulley to steel cable and tension inclination angle are introduced to characterize the bending stiffness of steel cable.Through the force analysis of contact area and non-contact area between steel cable and pulley,the calculation formula for calculating the tension of steel cable is obtained.The experimental results show that the tension value obtained by using the tension formula proposed here is in good agreement with the tension value directly measured by the sensor.In addition,the influence of structural parameters such as wrap angle,friction coefficient,radius ratio and tension inclination angle on the tension change of steel cable is analyzed.This study can provide theoretical guidance for precise motion control and structure design of surgical instruments.