A Class Of Nonlinear Discrete Dynamic Systems Based On U Model

In process of industrial production,most control processes suffer different nonlinear problems,for example,in the field of petrochemical industry and the process of heating furnaces and reactors,due to the serious nonlinearity,the general approximate linearization method cannot be applied directly.The research on control methods of nonlinear systems is currently an important research field.The main difficulty encountered in controlling nonlinear systems is that there is no proper framework of general mathematical models to accurately express the structure of nonlinear systems.Based on a large number of domestic and foreign literatures,this paper proposes control algorithm for nonlinear systems,and conducts some simulations and experimental research with the proposed algorithm.The main research work of this paper is as follows:(1)For a class of nonlinear dynamic systems,the controller output solution problem is transformed into a polynomial equation with the output of the current controller in the design of the generalized predictive controller based on U model,which reduces the difficulties encountered in the design of nonlinear control system to a certain extent.In this paper,the secant method is used to solve the current controller output.This method does not need to calculate the derivative and avoid the problems in the solution of the Newton-Raphson algorithm,it can reduce the complexity and time of calculation,while can have a faster convergence rate.(2)For a class of nonlinear dynamic systems,the nonlinear dynamic model is described by the structure of the U model which is a control-oriented model composed of the past input data of the controlled object,an improved generalized predictive control algorithm is proposed and the corresponding simulation research is conducted by using the control algorithm.