Abstract: Pipelayer is a kind of engineering machinery, which is used in the pipe laying and lifting
operation, and it would create a dangerous swing sharply under the external incentives. This can not
only reduce the lifting precision, but also cause collisions between hanging objects and structures. So
it has great importance for safety of pipelayer operation to analysis its system dynamic characteristic,
control and predict shimmy. First the article describes the working environment of pipelayer, then
proposes summary and comparison of relevant research of domestic and foreign. In this paper, the
mathematical model of hanging objects is established, and MATLAB is used to do data analysis. The
result shows that length of the sling, external excitation, landing speedcan lead to a great impact on
the dynamic response, shimmy frequency and angel of inner and outer surfaces.

Key words: pipelayer, nonlinear equations, dynamic analysis, MATLAB