A novel 4-RPTR parallel mechanism was presented,which can perform three-dimensional translations and rotation about X axis. Based on screw theory, the principles that the mechanism can perform the above motions were analyzed, the mobility of mechanism was calculated, and the drive input joints was chosen and discussed, the singularity of the parallel mechanism were analyzed. By use of multi-body system kinematics theory, the kinematics equation was set up, the forward and inverse position kinematics solutions were discussed and proved by use of numerical simulation. The 4-RPTR parallel mechanism replenishs four-DOF parallel mechanism family, its four branch

is the same, and its structure is semi-symmetric and simple, and the parallel mechanism can be applied in the fields of industrial assembly robots, coordinate measuring machines, posture adjusters, parallel machine tools, work platforms.

提出一种能实现空间三维平移和绕X轴旋转的4-RPTR型四自由度并联机构，运用螺旋理论分析了该并联机构的三维平移和一维转动的机构学原理，计算了机构自由度，进行了驱动输入选取与论证，并进行了奇异分析，运用多体系统运动学理论建立了该并联机构的运动学方程，进行了正反求解的讨论与数值验证。该并联机构是对三平移一转动四自由度并联机构的重要补充，它是一种支链完全相同的半对称并联机构，结构简单，可应用于工业装配机器人、坐标测量机、姿态调节器、并联机床、工作台等领域。

并联机构, 运动学, 奇异性, 螺旋理论