因实际生产的零件不可避免具有误差，装配体实际上是具有误差的系统，故在产品设计阶段对装配体进行误差分析具有重要意义． 文中从装配体的实际几何物理意义出
发，提出在每个误差特征的名义位置和实际位置处分别建立名义局部坐标系和实际局部坐标系，得到了装配体的递推误差分析模型; 由于几何尺寸误差通常较小，可根据刚体运动学的微分变换原理将递推误差分析模型线性化，并以具有并联尺寸链的复杂装配体为例，得到了线性化的误差分析解析式． 采用文中方法进行误差分析时，通过对不同类型的复杂装配体建立相应的系数矩阵，可极大减少计算的工作量，也易于编程实现． 文中最后给出了上述误差分析方法的一个应用实例．

In the process of production,the errors of the components of an assembly are inevitable,that is to say,the assembly is actually a system with errors.Hence,it is of great importance to conduct the tolerance analysis of assemblies during the design phase.In this paper,on the basis of the actual geometrical and physical meaning of assemblies,the thought of building the nominal and actual local coordinate systems respectively at the nominal and actual positions of each variable feature is proposed,and in this way,a recursive model is constructed for the tolerance analysis of assemblies.Since the errors of geometrical dimension are usually small,the constructed recursive model is linearized according to the differential transformation of rigid body kinematics,and by taking a complex assembly with parallel dimension chains as an example,a linearized analytic equation of tolerance analysis is obtained.When the above-mentioned new approach is applied to a tolerance analysis,by establishing a common coefficient matrix for different complex assemblies,the calculation work can be reduced and the programming can be facilitated.At last,this paper elaborates on the application of the new approach by using an example.