Research On Adaptive System For The Construction Control Of Long-Span Bridges

This thesis studied and analyzed the construction control of long-span bridges on the basis of improved algorithm for adaptive control system.Adaptive control is a kind of complex feedback control which accords with the analysis method of nonlinear system.In the process of object control,it presents a multivariable time-varying feedback control.Bridge construction monitoring(especially for the long-span bridges)is a complex system engineering based on modern control theories,and the aim is to ensure the quality and security of bridge and bridge construction.The core of the adaptive control system is the selection and use of the adaptive control model to choose the appropriate control method in view of the bridge construction process.So that it is able to adapt the nonlinear variation,predict,adjust,and make it close to the goal of theoretical design.Taking Longjingchong Bridge and Wuwei Second Bridge as the engineering background,the thesis adapted the adaptive control system to control and analyze the bridge construction process.The thesis analyzed the bridge construction with the finite element software MIDAS in different phases,and identified,estimated and corrected the design parameters and errors with the help of MATLAB software.It used Least Squares Method,Kalman Filter and Grey System Theory and improved algorithm to immediately adjust the model parameters such as laying elevation,prestressing force(inclined hanger forces),and so on in order to make the actual state of the bridge structure match with the ideal state.According to the characteristics of bridges construction,the thesis put forward the improved algorithm on the basis of the theory of improved model reference adaptive control to forecast the deflection deformation and internal force of bridge construction,and applied the method into the construction of continuous beam bridge and cable-stayed bridge.By monitoring,the practice has proved that construction of the closed accuracy and precision of the internal force met the design requirements and the feasibility of this method was verified.