Abstract: This paper deals with the random problem of the kinematic errors in a spatial linkage due to aberrations in the linkage parameters and clearancs in the joints. First, the stochastic models of the usual joints are established through introducing the concepts of clearance characteristic element and "clearance space". After deriving the probability density function of the joint clearance and making the probabilistic analysis of the resulted kinematic errors, the sampling formulas of the independent variables of the clearance characteristic elements are further deduced. Through Monte Carlo simulation, the numerical characteristics and distribution of the kinematic errors are then analysed by means of computer. For illustration the spatial RCSR linkage is taken as a numerical example.

Key words: 概率分析, 间隙运动副, 空间机构误差, 蒙特卡罗模拟