Study On Variable Structure Control Of Dynamic Fixed Floating Bridge

When dynamic fixed floating bridge operate in river,they are disturbed violently by water and wind, so constructing a dynamics model and realizing precise position fixed for dynamic fixed floating bridge in river have become an urgent problem need to be solved in the research of dynamic fixed floating bridge.The characteristics of motion and disturb acted on dynamic fixed floating bridge in river are analyzed in the paper,combining theoretical knowledge of multi-rigid dynamics modeling,construct the dynamic model disturbed by water and wind.For the need of actual control, be further simplified dynamics model bythe needs of actual control.Floating bridge itself is a complex multi-body system. When acted on uncertainty disturb, it is hard to realize accurate position fixed. The variable structure control is suitable to resolve the control problem of complex systems ,beacause of the nature of nonlinear switch control. In addition, its sliding mode has the notable advantages of invariance with internal parameters change and external disturb of the system Thus when there are strong interference in resolving control problem of complex systems, variable structure control become an effective method.The variable structure control techniqueis applied to position control of dynamic fixed floating bridge in river on the basis of dynamics model constructed above.First,according to the control theory of variable structure control, combining the study object in this paper, variable structure controller are designed for the dynamic fixed system of floating bridge.Tendency ration sliding mode is used as switching function when designing the variable structure controller.Then, simulation are carried out to the dynamic fixed control system of floating bridge. And by analyzing simulation results , reliability and validity of the dynamic model established in this paper are verified .At last, for the inherent chattering problems of variable structure control,design a variable structure controller of boundary layer, eliminating the high frequency chattering of the system. In conclusion,in order to avoid blindness when debug system parameters, using ant colony optimization algorithm optimize parameters of variable structure control.By the optimization controller, carry out simulation research again.The simulation results show that,on one hand,the dynamics model constructed in the paper can reflect truly the motion state of floating bridge in river,on the other hand, the variable structure controller contructed in this paper has nice control effects for resisting on the disturb of water and wind when realizing precision dynamic fixed of floating bridge in the river.