奇异性是机构的固有性质，严重影响其运动、力传递性能。六自由度并联机构中应用最广的是Stewart并联机构，它的奇异曲面方程高度非线性，为奇异性分析带来了较大困难。为此，以一种支链冗余的可重构Stewart并联机构为研究对象，基于Grassmann线几何理论辨识了重构前、后的奇异位形，并提出了奇异消除方法。首先，运用Grassmann线几何的线簇秩理论，辨识出机构重构为“3-2-1”和“2-2-2”构型时的36种奇异位形，并揭示它们的几何条件及关联性。其次，通过剖析奇异性机理，提出了一种基于拓扑重构的奇异位形消除方法；在此基础上，通过引入局部传递指标以度量奇异区域，还能够避免机构在运动过程中接近奇异位形。最后，通过数值算例及虚拟实验，验证了新方法的有效性，为Stewart可重构并联机构的实际应用奠定了理论基础。

 Singularity is an inherent property of mechanisms, which severely affects their motion and force transmission performance. Among six-degree-of-freedom parallel mechanisms, the Stewart parallel mechanism is the most widely used, yet its singular surface equation is highly nonlinear, posing significant challenges for singularity analysis. To address this issue, a reconfigurable Stewart parallel mechanism with limb redundancy is taken as the research object. Based on Grassmann line geometry theory, the singular configurations before and after reconfiguration are identified, and a singularity elimination method is proposed. First, using the line cluster rank theory of Grassmann line geometry, 36 types of singular configurations are identified for the mechanism reconfigured into the “3-2-1” and “2-2-2” configurations, and their geometric conditions and interrelations are revealed. Second, by analyzing the singularity mechanism, a singularity elimination method based on topological reconfiguration is proposed. On this basis, a local transmission index is introduced to measure singular regions, thereby preventing the mechanism from approaching singular configurations during motion. Finally, numerical examples and virtual experiments validate the effectiveness of the proposed method, laying a theoretical foundation for the practical application of Stewart reconfigurable parallel mechanisms.