Exechon机器人中的并联模块2-UPR-SPR机构由内副P驱动（U：虎克铰，P：移动副，R：转动副，S：球铰），运动部分质量大且对刚度有一定影响。提出外副驱动的2-PUR-PSR并联机构，具有和2-UPR-SPR相同的自由度数目和性质，采用螺旋理论分析了2-PUR-PSR并联机构的自由度，确定了其两条转轴，建立了位置逆解模型。基于螺旋理论得到描述机构运动/力传递性能的局部传递指标和全域优质运动/力传递空间比指标。借助空间模型法对2-PUR-PSR并联机构进行尺度综合，获得性能分布图谱，确定最优尺寸区域。2-PUR-PSR并联机构在加工、装配等方向有较好的应用前景。
The 2-UPR-SPR parallel module of the Exechon manipulator is actuated by inner prismatic pairs, which leads to heavy moving weight and negative effects on stiffness (where U denotes a universal joint, P a prismatic joint, R a revolute joint, and S a spherical joint). A 2-PUR-PSR parallel manipulator with fixed linear actuators is proposed, which has the same degrees of freedom and numbers of joints as the 2-UPR-SPR parallel module. Kinematic analysis and dimensional synthesis of the proposed manipulator are discussed. First, the mobility and inverse kinematic module of the 2-PUR-PSR parallel manipulator are analyzed. Then, based on screw theory, the local transmission index and global transmission workspace are obtained, which can be used to describe the motion/force transmission performance. Finally, the optimal design space is used to conduct dimensional synthesis. The atlases of performance are obtained to determine the optimum region. The 2-PUR-PSR parallel manipulator has great potentials in applications like machining and assembling.
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