Macroeconomic Uncertainty And Robust Control

Since the founding of China,there have been several serious imbalances between supply and demand situations,which have caused a serious impact on the economic system of our country.So it is very important to effectively control the economic system.In order to carry out this regulation more effectively,it is necessary to make a correct theoretical analysis on the balance between the total supply and the total demand of our society.And more important,it is urgently needed to conduct some quantitative studies on the basis of theoretical research and qualitative analysis.However,China's economic system reform has not been perfect yet,and there are still deficiencies in the adjustment of structure,making the macroeconomic system model structure constantly changing.So the model established by the predecessors fails to accurately describe the current economic development situation.In practical engineering,a control system often contains uncertainties,belonging toone of the two categories:parameter uncertainty and external disturbance.Similarly,the economic system is also influenced by the uncertainties.This thesis will touch upon some important issues for an economic system affected by these two kinds of uncertainties.First,based on the study of the national total supply and demand equilibrium model established by Huang Guoshi of Xiamen University,this thesis presents a modified supply-demand model by taking into account the uncertainties caused by the parameter perturbations of an economic system in the modeling process.By introducing the concept of linear interval,the uncertainties are equivalently described by linear intervals.The model parameters are estimated and validated by using the multivariate linear regression and the two-stage least squares.The collected data shows that the modified model is more applicable to China's situation.Second,this thesis studies how to coordinate the monetary and fiscal policies for an economic system with perturbations to ensure that the national aggregate demand curve can track the desired trajectory.The coordination between the monetary and fiscal policies is transformed into the robust tracking control problem whose solvability is then expressed in the form of linear matrix inequalities(LMIs).The simulation via the collected data,gives rise to a useful suggestion of a rational combination of the fiscal expenditure and money supply to keep healthy development of China's economy.Finally,this thesis also considers the mixed effects of uncertainties and external perturbations,and designs a robust controller by using the H_? control method to ensure that the national total supply and demand equilibrium system can maintain the original movement trajectory.