三构态驱动变胞并联球铰设计与分析

不同于现有利用约束奇异和支链奇异实现的变胞并联机构,本文通过开启与锁死驱动副的方式,利用有限旋量法提出了一种可以实现一维转动、二维转动和三维转动的三构态驱动变胞并联球铰。根据螺旋理论分析机构各构态的自由度,利用机构的结构特征和几何约束关系分析其运动学。基于驱动变胞并联球铰(Sm),通过串联P副和U副,形成SmPU变胞支链,提出一种八模式3-SPS/SmPU驱动变胞并联机构。此种通过开启与锁死驱动实现驱动变胞球铰的方法也适用于其他变胞运动副的综合,变胞方式简便易行,且该类变胞运动副可有效避免变胞过程中的约束奇异以及支链奇异。

Design and Analysis of Actuated Metamorphic Parallel Spherical Joint of Three Configurations

Different from the existing methods by using constraint singularity or the chain singularity to synthesis metamorphic parallel mechanisms, an actuated metamorphic parallel spherical joint of full rotation of the one-dimensional, two-dimensional and three-dimensional rotation by way of opening and locking actuated kinematic pair was presented through the method of finite screw. Using the screw theory, the degree freedom of three configurations of the actuated metamorphic parallel spherical joint was analyzed, the mechanism kinematics was studied according to the structure characteristics and geometric constraints of the actuated metamorphic parallel spherical joint. Finally, SmPU actuated metamorphic chain was obtained according to integrating the actuated metamorphic parallel spherical joint (Sm) with P kinematic pair and U kinematic pair serial limb. Based on the SmPU actuated metamorphic chain, 3-SPS/SmPU actuated metamorphic parallel mechanism of six motion modes was presented. The method of the type synthesis actuated metamorphic parallel spherical joint can also be applied to type synthesis other actuated metamorphic parallel joints, the metamorphic method was simple and effective, and constraint singularity and the chain singularity could be avoided effectively in the metamorphic process.