以型转化理论为基础 ,通过引入等效连杆长度及广义约束角的概念 ,提出了求解平面连杆机构输出变量误差统计分布规律的通用算法—虚拟变量法 ,并编制了相应的通用程序。对任意复杂平面机构 ,通过调用基本杆组单元的子程序 ,根据型转化约束方程 ,可方便的求解输出变量误差的统计特征量。 Based on the theory of transformation, the concept of equivalent connecting rod length and generalized restraining angle is introduced. A universal algorithm for calculating the statistical distribution of output variable errors of planar linkage mechanism is proposed, and a corresponding general procedure is developed. For any complex plane mechanism, the statistical feature of the output variable error can be easily solved by calling the subroutine of the basic rod set unit according to the type transformation constraint equation.