含恰约束支链的驱动变胞机构构型综合与分析

Type Synthesis and Analysis of Class of Actuated Metamorphic Mechanisms with Suitable Constrained Branch

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,通过开启与锁死驱动副的方式,基于3-RRR球面机构(Sm),利用螺旋理论提出了一类含主动混联恰约束支链的多模式驱动变胞并联机构。针对所综合的3-SPS/SmPU驱动变胞并联机构,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建立其运动学模型。此种通过开启与锁死驱动副实现并联机构变胞的方法也适用于其他变胞并联机构的构型综合,其变胞方式简便易行,全构态逆运动学求解简单,且该类变胞并联机构可有效避免变胞过程中的约束奇异和支链奇异。

Different from the existing methods by using constraint singularity or the chain singularity to synthesis metamorphic parallel mechanisms,based on the 3-RRR spherical parallel mechanism(Sm),according to the method of screw theory,a class of multi-mode actuated metamorphic parallel mechanisms with active hybrid suitable constrained branched chain by way of opening and locking actuated kinematic pair was presented.Using the screw theory,the degree freedom of the whole configurations of 3-SPS/SmPU multi-mode actuated metamorphic parallel mechanism of the proposed actuated metamorphic parallel mechanism with active hybrid suitable constrained branched chain was analyzed,the mechanism kinematics was studied according to the structure characteristics and geometric constraints of 3-SPS/SmPU actuated metamorphic parallel mechanism.The method of type synthesis multi-mode actuated metamorphic parallel mechanism with active hybrid suitable constrained branched chain can be also applied to type synthesis other actuated metamorphic parallel mechanisms,the metamorphic method was simple and effective,the inverse kinematics of the whole configurations was easy to solve,and constraint singularity and the chain singularity could be avoided effectively in the metamorphic process.