一种可用于微创手术的并联机构运动学分析与性能优化

与串联机构相比，并联机构具有刚度好，精度高，响应快等优点，适合用于医疗领域。微创穿刺活检等手术要求机器人机构能够输出远中心运动。提出了一种用于微创手术的新型远中心并联机构，其分支内部包含平行四边形闭环子链。采用螺旋理论对机构自由度进行了分析，证明其能输出两个转动运动和一个移动运动，且所有运动均通过远端固定中心。对机构进行位置分析，建立了驱动参数与末端参数之间的映射。通过速度分析建立了雅可比矩阵，并分析得到了机构的奇异位形，包括逆解奇异、正解奇异和混合奇异。应用搜索法分析了机构的工作空间。采用运动/力传递指标对机构进行了性能分析，绘制工作空间内的性能图谱。以优质空间大小为目标对机构进行了尺度优化。

Kinematics Analysis and Performance Optimization of a Parallel Manipulator for Minimally Invasive Surgery

Compared with serial manipulators, parallel manipulators have the advantages of good rigidity, high precision and quick response, which are suitable for medical field. Operations in minimally invasive biopsies require robotic manipulators that can output remote center of motion. A novel parallel manipulator with remote center of motion is proposed for minimally invasive surgery. Each limb of the parallel manipulator includes a closed-loop parallelogram. Mobility analysis is carried out based on screw theory, which shows the manipulator has two rotational and one translational degrees of freedom passing through a fixed remote center. Mapping between the input parameters and the end-effector output parameters is obtained through position analysis. Jacobian matrix is established based on velocity analysis, which is used to determine the singular configurations of the manipulator. It has inverse singularities, direct singularities and combined singularities. Workspace is obtained using a search method. Performance analysis is conducted based on the motion/force transmission index. Performance distributions in the workspace are sketched. Optimal design is carried out to improve the global performance of the parallel manipulator.