具有连续转轴的对称2R1T三自由度并联机构型综合

为综合出更多具有连续转轴的并联机构新机型，提出一种具有连续转轴的两转一移（2R1T）并联机构型综合新方法。运用螺旋理论，给出该类机构约束螺旋的空间布置，提出并联机构连续转轴的判别条件，确定分支运动副类型及空间位置关系。基于分支约束力与分支运动副之间的几何位置关系，证明了该类机构能够实现连续转动。利用该方法对具有平面上任意直线为连续转轴的对称两转一移并联机构进行综合，并仿真验证了研究结果的正确性。该综合方法简单、有效。

Type Synthesis of 2R1T Symmetrical Parallel Mechanism with Continuous Rotation Axes

To get more parallel mechanisms with continuous rotation axes (CRAs), a new synthesis method which could synthesize 2 rotations and 1 translation (2R1T) parallel mechanisms with continuous rotation axes lying on a plane is proposed. Based on screw theory, the space distribution of the constraint forces of this kind of parallel mechanism (PM) is given out. The discriminative conditions of continuous rotation axe are proposed, and the types of kinematic pairs of the branch and their spatial positions are specified. Based on the geometrical relation of the kinematic pairs of the branch and the constraint force of the branch, the principle of the moving platform's continuous rotation is explained. Using the proposed method, the symmetrical 2R1T parallel mechanisms with any line on a plane as CRA are synthesized systematically. The case analysis of the synthesized mechanism is carried out, which verified the correctness of the synthesized mechanisms. The synthesis method is simple and effective.