Abstract: Geared system plays a critical role in wind power, aerospace, car, shield tunneling machine and other mechanism equipment. The dynamic characteristics of system will directly affect the performance of mechanism equipment. However, due to complicated structures, richness of internal and external excitations and nonlinear factors, and complex work environment, the dynamic analysis of gear train is more complex than that of other mechanical systems. In addition, owing to errors of manufacturing, processing, and assembling, wear, lubrication, operating environment and other factors, the internal and external excitations and system parameters are always uncertain. Those uncertain factors should be considered in the dynamic analysis of geared system. Many researchers have carried out extensive and in-depth research on the uncertain dynamic analysis of geared systems. The advances of research are reviewed from the description of uncertain factors, method for solving dynamic equations, analysis of dynamic characteristics, reliability analysis and optimization design, and experiments of uncertain analysis. Some critical issues for further study are also summarized.

Key words: dynamics, gear train, random error, statistical analysis, uncertainty