具有部分解耦运动特性的空间移动并联机构型综合

Type Synthesis of Spatial Translational Parallel Mechanisms with Partially Decoupled Kinematic Characteristics

摘要:

机构承载能力与其运动耦合性密切相关,而已有的型综合方法较少兼顾考虑机构运动耦合性和承载能力。本文基于驱动力螺旋理论建立运动解耦特性与驱动力螺旋之间的关系,提出了一种具有部分解耦运动特性的空间移动并联机构型综合方法。根据驱动力螺旋与关节运动之间的关系,建立机构运动耦合性方程;根据并联机构运动特性和支链连接度,综合得到具有空间移动运动的基础支链,并提出了构建产生不同驱动力螺旋支链的方法;将机构动平台所需力线矢分解成若干个力线矢,重新合成后得到了机构所需的驱动力螺旋矩阵;根据不同驱动力螺旋的支链类型,综合得到符合驱动力螺旋矩阵支链,组装得到所期望的机构;分析综合得到的机构自由度和运动学,验证了所提方法的正确性。研究结果为设计不同承载能力的解耦并联机构提供依据。

Abstract:

The load-bearing capacity of a mechanism is closely related to its kinematic coupling,yet existing type synthesis methods seldom take both the kinematic coupling characteristics and the load-bearing capacity into account. The spatial geometric relationship between partially decoupled motion characteristics and the actuation wrench based on the actuation wrench matrix was established,and then a type synthesis method for translational parallel mechanisms with partially decoupled motion characteristics was proposed. Firstly,based on the actuation wrench theory,the coupling equation of the mechanism was established. Secondly,according to the kinematic characteristics of the translational parallel mechanism and the degree of connection of a branch,the basic branch with spatial translational was synthesized,and the branch types producing different actuation wrenches were given. Once again,the required force line vectors for the moving platform were decomposed into several force line vectors,and the required actuation wrench matrix was obtained by resynthesizing the force line vectors. Then,according to the type of branch producing different actuation wrenches,the branches conforming to the actuation wrench matrix were synthesized,and the spatial translational parallel mechanisms with partially decoupled motion characteristics were assembled. Finally,the correctness of the proposed method was verified through the analysis of degrees of freedom and mechanisms' kinematics. The research results can provide a basis for designing parallel mechanisms with different capacities.