基于灵巧度的手术机械臂尺寸与结构优化

Dexterity-based optimization of dimension and structure for a surgical robot

为了通过优化机械臂的尺寸来提高其运动性能,提出了一种基于运动学综合性能指标的机构尺寸和结构的优化方法。通过分析手术机械臂运动学雅可比矩阵奇异值,建立了全域空间条件数均值与全域空间条件数波动值的综合灵巧度指标,对远心点调整机构的尺寸进行了优化。基于对关节结构的有限元分析,优化其结构,实现了机械臂的轻量化设计。优化结果显示:优化后机械臂远心点的工作空间仍满足手术操作的需求,综合灵巧度指标提高了14.8%,被动关节质量减少了21.9%,一阶固有频率和最大应力指标也都有所提高。优化结果很好地满足了微创手术对机械臂灵活性及轻量化的要求。

To improve the kinematic performance of robotic arms by optimizing their size, an optimization method of mechanism size and structure based on kinematic comprehensive performance index was proposed. By analyzing the singular value of kinetic Jacobian matrix on the surgical robotic arm, a comprehensive dexterity index function based on the average and volatility of the condition number was established. The dimensional parameters of the re- mote center mechanism were optimized. Based on finite element analysis on the joint structure, the structure was optimized and the lightweight design of the robotic arm was achieved. Optimization results show that the workspace at the remote center of the robot arm after optimization still met operational requirements, the index of comprehen- sive dexterity increased by 14. 8%, and the mass of passive joints decreased by 21.9%. In addition, first-order and maximum stress indices improved. The optimization results properly meet the requirements of minimally inva- sive surgery for the flexibility and light weight of a robot arm.