An enhanced approach to control stability in an active column critical to buckling

This paper studies the approach to control uncertainties in a simple column structure critical to buckling by actively stabilising the column. The buckling behaviour of a slender column, built in vertically at the base and pinned at the upper end is examined with and without additional active stabilisation. When the column is loaded by an axial compressive force equal to its individual critical buckling load, a critically stable equilibrium state occurs. When loaded above its critical buckling load, the passive column may buckle due to imperfections or lateral disturbance forces. The active stabilisation concept is based on the idea to force the column into its second bending de ection mode which enables the column, theoretically, to carry a load three times higher than the critical buckling load of a straight column with the same constraints. For that, actively controlled forces which are acting close to the column's clamped base increase the column's strength against buckling in real-time. It can be shown that the column can be stabilised in two directions in one plane with a combined feedforward and feedback control, even when the axial compressive force exceeds the original critical buckling load.