Dynamic characteristic was analyzed for the hydraulic anti-sway system,and established the mathematical model of crane system by using Lagrange equation. For crane load swing problems, established the Parametric oscillation model of crane, through coordinate transformation, transformed the differential equation of crane into the standard form of Hill equation, and with research on Hill equation we can get the condition about damped oscillation. With the introduction of the parameter plane, the stable map of Hill equation can be drawed, i.e. the map of load damped oscillation. We used MATLAB-Simulink to simulate. The vertical motion of hoist has obvious influence on load sway. Through controlling cable length lifting motor has some good help to lowering sway angl of crane load.
