应用隐函数存在定理 ,推导出平面闭链 RRRRP五杆机构柔性工作空间边界的条件 ,即输出杆与相连的连架杆共线 ,以及另一连架杆与相连的滑块导路垂直 .利用三角不等式推导出平面闭链 RRRRP五杆机构存在无条件曲柄的不等式条件 ,分析平面闭链 RRRRP五杆机构在保证无条件曲柄存在条件下 ,其工作空间边界曲线的构成及其特征 .在此基础上提出了平面闭链 RRRRP五杆机构的工作空间求解算法 .通过算例验证了数学模型的正确性 . The existence theorem of implicit function is used to derive the condition of flexible working space boundary of RRRRP five-bar linkage in planar closed-chain, that is, the output rod is collinear with the connected frame rod and the other frame rod is perpendicular to the connected slider guideway. Inequality The inequality conditions of the unconstrained crank with planar closed-chain RRRRP five-bar mechanism are deduced, and the composition and characteristics of the workspace curve of planar closed-chain RRRRP five-bar mechanism in the presence of unconditional crank are analyzed. On this basis, The Algorithm of Working Space Solving for Five-bar Mechanism of Planar Closed-chain RRRRP The correctness of the mathematical model is verified by an example.