Research On The Modeling And Control Of Cement Particle Size

The cement grinding is an indispensable part in the industrial production of cement,but it is difficult to achieve a satisfactory result for the strong coupling,large delay and inertia which cause the cement product quality fluctuates greatly.The particle size distribution of the cement is an important control index in the production of the cement grinding,which directly determine the quality of the cement.In order to keep the cement grinding process operate efficiently and stalely,this paper focused on the multiple intervals particle size distribution of cement to build the model and research the control algorithm,and an automatic control system for particle size of cement grinding is developed,the main contents of the article are as follows.?.In order to describe the complex dynamic process of cement grinding completely,the granularity system is divided into two sub models of 3?m and 3-32?m to build the model separately.The main factors which affecting the particle size are analyzed and the main control variables are confirmed,and then the standard working conditions is ascertained.For building the model of less than 3?m with small control hysteresis,the structure of the model is assumed as a difference equation first,and then based on the data of actual operation of the production process,the order of the model is obtained by the AIC pricing criterion and the parameters in the model are identified by genetic algorithm.For building the model of 3-32?m with large control delay,a transfer function with control delay is set as the model,based on the engineering background preset a lag interval and obtain the best parameters of the model by the least square algorithm.?.For the sake of achieving a stable control result of cement particle size,the advanced control algorithm is studied based on(1).Aiming at the problem of controlling volatility of particle size less than 3?m,based on PID control and simultaneous perturbation stochastic approximation(SPSA)algorithm,we give the random disturbed to the parameters of PID controller and apply the observed I/O data to search the optimal PID parameters by the SPSA optimization algorithm to control the granularity less than 3?m stalely and quickly.For the large lag coefficient and control instability of the 3-32?m granularity,the state transformation is used to change the model with no time delay,and then the sliding mode control of the discrete system is designed and the condition of stability is given by Lyapunov to realize the stability control with large lag.?.According to the on-line particle size analyzer of cement,combined with expert control and Bang-Bang control and the two advanced control methods,a kind of automatic control system for cement grinding granularity is designed.The control scheme is given for different working conditions and the automatic control system is designed by VB based on the user requirements and functions.The practical application shows the superiority of the system.