The Research On Anti-swing And Pinpoint Control Of Gantry Crane Based On Sliding Mode Variable Structure Control

Gantry cranes are widely used in industry for load transfer. However, as its unique structure, it unavoidably causes swaying as working, which may cause load damage and other types of hazards, and hence reduces the operation efficiency. So how to reduce the swaying promptly is a representative question studied in control filed home and abroad. This thesis can be divided into three sections as follows:Firstly, based on Lagrange equations, a three-dimensional mathematical model is derived for typical underactuated mechanical gantry crane system, and the linearized three-dimensional mathematical model is also presented with the linearization conditions, besides, MATLAB results demonstrate the effectiveness of the mathematical model.Secondly, the sliding mode variable structure approach is applied to control the position and load swing of a3D gantry crane system, and it adopts a modified constant speed reaching law, which can not only reduce effectively the tremble caused by variable structure control but make the crane system come to a stable equilibrium state quickly. Comparing with the PID control, the fast and accurate positioning without overshoot and better anti-swing control can be provided for a crane system by the controller which is designed by variable structure control based on sliding model.Finally, through simulation experiment in different load quality, different crane weight, different friction coefficient and external disturbance of system, we draw a conclusion that the sliding mode variable structure control has stronger robustness than the other general control, and is feasible for practical application.