Optimization of Vibration Reduction on the Mast by Active Stay System

An investigation of vibration reduction at the top of the mast by active control system is presented. Two typical external excitations, impact and random dynamic load, are considered. For each type of load, a cost function is defined and its optimal law is solved. Besides, an active stay system is designed to offer an active force on the mast.By comparing the direct stiffness increment and fixed stay auxiliary methods, it is shown that the active stay system has the fastest decay property among these methods for impact induced motion. For random exciting load, it has superior effect of peak suppressed in spectral density response than other two methods and its standard variations much lower than other cases compared. In addition, the lateral translation and slope accelerations at the top of the mast reduced by the active stay system is also the most effective. Numerical examples demonstrate that the active stay system with optimal law is a powerful and feasible scheme for mast vibration reduction.